U.S. patent application number 17/587775 was filed with the patent office on 2022-06-16 for hydrogen fueling systems and methods.
This patent application is currently assigned to Ivys Inc.. The applicant listed for this patent is Ivys Inc.. Invention is credited to Bryan Gordon, Christopher John O'Brien, Darryl Edward Pollica.
Application Number | 20220186882 17/587775 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-16 |
United States Patent
Application |
20220186882 |
Kind Code |
A1 |
Pollica; Darryl Edward ; et
al. |
June 16, 2022 |
HYDROGEN FUELING SYSTEMS AND METHODS
Abstract
According to aspects, hydrogen fueling systems and methods are
provided, including vehicle-to-vehicle communication techniques,
hydrogen cooling techniques and/or hydrogen dispenser control
techniques that facilitate improving aspects of a hydrogen fueling
station.
Inventors: |
Pollica; Darryl Edward;
(Melrose, MA) ; O'Brien; Christopher John;
(Waltham, MA) ; Gordon; Bryan; (Goffstown,
NH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ivys Inc. |
Waltham |
MA |
US |
|
|
Assignee: |
Ivys Inc.
Waltham
MA
|
Appl. No.: |
17/587775 |
Filed: |
January 28, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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17374268 |
Jul 13, 2021 |
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17587775 |
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63195435 |
Jun 1, 2021 |
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63131953 |
Dec 30, 2020 |
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63057163 |
Jul 27, 2020 |
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63057159 |
Jul 27, 2020 |
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63057150 |
Jul 27, 2020 |
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63051181 |
Jul 13, 2020 |
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International
Class: |
F17C 9/00 20060101
F17C009/00 |
Claims
1. A hydrogen cooling system comprising: a first reservoir
comprising a first tank configured to hold first coolant comprising
at least one phase-change material; a refrigeration unit coupled to
the first reservoir to chill the first coolant to cause the
phase-change material held by the first tank to change from a first
state to a second state; and a first heat exchanger configured to
thermally couple the first coolant held by the first reservoir and
hydrogen gas flowing through the heat exchanger via heat exchange
with the first coolant.
2. The hydrogen cooling system of claim 1, wherein the first heat
exchanger comprises an annular heat exchanger having at least one
coil.
3. The hydrogen cooling system of claim 2, wherein the annular heat
exchanger is positioned within the first tank of the first
reservoir.
4. The hydrogen cooling system of claim 3, wherein the annular heat
exchanger is positioned within the first tank so that the at least
one coil is in contact with the at least one phase-change material
to transfer heat from the hydrogen gas flowing through the at least
one coil to the at least one phase change material held by the
first tank.
5. The hydrogen cooling system of claim 1, wherein the first
coolant comprises a second coolant that does not transition from a
first state to a second state when chilled by the refrigeration
unit.
6. The hydrogen cooling system of claim 5, wherein the first heat
exchanger is configured to receive the second coolant, and wherein
the hydrogen gas is chilled based at least in part via heat
exchange with the second coolant.
7. The hydrogen cooling system of claim 6, wherein the first heat
exchanger includes an annular heat exchanger comprising: a shell
through which the second coolant is circulated; and at least one
coil through which the hydrogen gas flows, wherein the annular heat
exchanger chills the hydrogen gas via heat exchange between the
hydrogen gas flowing through the at least one coil and the second
coolant circulated through the shell.
8. The hydrogen cooling system of claim 1, wherein the
refrigeration unit is a small-capacity refrigeration unit.
9. The hydrogen cooling system of claim 8, wherein the first
reservoir is a large-volume reservoir.
10. The hydrogen cooling system of claim 8, wherein the first
reservoir is a small-volume reservoir.
11. The hydrogen cooling system of claim 1, wherein the at least
one phase change material held by the first tank comprises a first
phase-change material that changes from the first state to the
second state at less than or equal to -10.degree. C.
12. The hydrogen cooling system of claim 1, wherein the at least
one phase change material held by the first tank comprises a first
phase-change material that changes from the first state to the
second state at less than or equal to -20.degree. C.
13. The hydrogen cooling system of claim 1, wherein the at least
one phase change material held by the first tank comprises a first
phase-change material that changes from the first state to the
second state at less than or equal to -30.degree. C.
14. The hydrogen cooling system of claim 1, wherein the at least
one phase change material held by the first tank comprises a first
phase-change material that changes from the first state to the
second state at less than or equal to -40.degree. C.
15. The hydrogen cooling system of claim 7, wherein the first
reservoir is integrated in a housing of the refrigeration unit.
16. The hydrogen cooling system of claim 15, wherein the at least
one phase change material is held by the first tank separately but
thermally coupled to the second coolant.
17. The hydrogen cooling system of claim 1, further comprising: a
second reservoir comprising a second tank configured to hold second
coolant comprising at least one phase change material; and a second
heat exchanger configured to thermally couple the second coolant
held by the second reservoir to hydrogen gas flowing through the
second heat exchanger via heat exchange with the second coolant,
wherein the refrigeration unit is coupled to the second reservoir
to chill the at least one phase change material held by the second
tank to cause the at least one phase change material to change from
a first state to a second state.
18. A hydrogen cooling system comprising: a first reservoir
comprising a first tank configured to hold first coolant comprising
at least one phase-change material; a second reservoir comprising a
second tank configured to hold second coolant; a refrigeration unit
coupled to the first reservoir to chill the at least one
phase-change material to cause the at least one phase-change
material to change from a first state to a second state, and
coupled to the second reservoir to chill the second coolant; a
first heat exchanger configured to thermally couple the first
coolant and hydrogen gas flowing through the first heat exchanger
to chill the hydrogen gas to a first temperature via heat exchange
with the first coolant; and a second heat exchanger configured to
thermally couple the second coolant and the hydrogen gas chilled to
the first temperature to chill the hydrogen gas to a second
temperature via heat exchange with the second coolant and to
provide the chilled hydrogen gas to at least one first
dispenser.
19. The hydrogen cooling system of claim 18, wherein the first heat
exchanger comprises a first annular heat exchanger having at least
one coil, wherein the annular heat exchanger is positioned within
the first tank of the first reservoir so that the at least one coil
is in contact with the at least one phase change material to
transfer heat from the hydrogen gas flowing through the at least
one coil to the at least one phase change material.
20. The hydrogen cooling system of claim 19, wherein the second
heat exchanger includes a second annular heat exchanger comprising:
a shell configured to circulate the second coolant; and at least
one coil configured to receive the hydrogen gas at the first
temperature, wherein the hydrogen gas is chilled to the second
temperature via heat exchange between the hydrogen gas and the
second coolant circulating through the shell.
21. The hydrogen cooling system of claim 20, wherein the at least
one phase-change material comprises a first phase-change material
that changes from the first state to the second state at less than
or equal to 0.degree. and greater than or equal to -10.degree. C.
so that the first annular heat exchanger chills the hydrogen gas to
between 0.degree. and -10.degree. C., and wherein the second
annular heat exchanger chills the hydrogen gas to below -10.degree.
C.
22. The hydrogen cooling system of claim 20, wherein the at least
one phase-change material held by the first tank comprises a first
phase-change material that changes from the first state to the
second state at less than or equal to 0.degree. and greater than or
equal to -20.degree. C. so that the first annular heat exchanger
chills the hydrogen gas to between 0.degree. and -20.degree. C.,
and wherein the second annular heat exchanger chills the hydrogen
gas to below -20.degree. C.
23. The hydrogen cooling system of claim 22, wherein the second
annular heat exchanger chills the hydrogen gas to -30.degree. C. or
less.
24. The hydrogen cooling system of claim 22, wherein the second
annular heat exchanger chills the hydrogen gas to -40.degree. C. or
less.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. .sctn.
120 and is a continuation (CON) of U.S. application Ser. No.
17/374,268, entitled "HYDROGEN FUELING SYSTEMS AND METHODS" filed
on Jul. 13, 2021, which claims priority under 35 U.S.C. .sctn. 119
to U.S. Provisional Application Ser. No. 63/195,435, filed Jun. 1,
2021 and titled HYDROGEN FUELING SYSTEMS AND METHODS, to U.S.
Provisional Application Ser. No. 63/131,953, filed Dec. 30, 2020
and titled VEHICLE COMMUNICATION IN HYDROGEN GAS DISPENSING
SYSTEMS, to U.S. Provisional Application Ser. No. 63/057,163, filed
Jul. 27, 2020 and titled VEHICLE TO DISPENSER COMMUNICATION METHODS
AND APPARATUS, to U.S. Provisional Application Ser. No. 63/057,150,
filed Jul. 27, 2020 and titled HYDROGEN DISPENSER METHODS AND
APPARATUS, to U.S. Provisional Application Ser. No. 63/057,159,
filed Jul. 27, 2020 and titled HYDROGEN COOLING METHODS AND
APPARATUS, to U.S. Provisional Application Ser. No. 63/051,181,
filed Jul. 13, 2020 and titled VEHICLE TO DISPENSER COMMUNICATION
METHODS AND APPARATUS, each application of which is herein
incorporated by reference in its entirety.
BACKGROUND
[0002] Hydrogen fuel cell vehicles (HFCV) are emerging as a
zero-emission alternative to internal combustion engine vehicles.
HFCVs operate by providing compressed hydrogen to a fuel cell stack
which converts the hydrogen into electricity to drive an electric
motor. Similar to internal combustion engine vehicles, HFCVs are
equipped with fuel tanks that must be refilled periodically. To
safely and/or efficiently dispense hydrogen gas to a vehicle, a
number of parameters are typically required, including tank volume,
measured pressure and measured temperature. Conventionally, fueling
parameters are communicated between a hydrogen gas dispenser and
the vehicle using the set of protocols specified by the Infrared
Data Association (IrDA) for optical line-of-sight (LOS) wireless
communication. IrDA provides a communication scheme with a low bit
error rate suitable for communication between a dispenser on a
vehicle.
[0003] HFCVs often have fuel tanks that utilize Compressed Hydrogen
Storage Systems (CHSS), which are very sensitive to high
temperatures. Many current fueling protocols adopted by hydrogen
refueling stations require gaseous hydrogen fuel to be cooled
between -40.degree. C. to -17.5.degree. C. prior to dispending to
the vehicle in order to ensure the vehicle's CHSS maintain their
bulk gas temperatures below 85.degree. C. regardless of ambient or
previous driving conditions. Current fueling stations typically
employ one of two types of heat exchangers to cool hydrogen gas for
dispensing into the fuel tank of an HFCV.
[0004] A first conventional heat exchanger includes a large cast
aluminum block (typically, in a range between 600-1000 kg) that is
buried underneath the fuel dispenser and that is cooled to very low
temperatures by a refrigeration or condenser unit (also referred to
as a "chiller" or "cooler") via refrigeration tubing about which
the aluminum block was cast. The aluminum block is also cast with
stainless steel tubing through which hydrogen gas is passed to cool
the hydrogen gas before dispensing the hydrogen into the fuel tank
of the vehicle. Specifically, heat exchange between the hydrogen
gas flowing through the stainless-steel tubing and the chilled
aluminum block cools the hydrogen gas to the low temperatures
needed for HFCV dispensing.
[0005] A second conventional heat exchanger employs a
diffusion-bonded heat exchanger that uses a conventional
plate-to-plate configuration that is designed for high pressure.
The diffusion-bonded heat exchanger is fluidly coupled to a
reservoir of coolant that is brought down to the low temperatures
needed for hydrogen gas dispensing by a large refrigeration unit
(chiller). Chilled coolant from the reservoir is passed through the
diffusion-bonded heat exchanger along with hydrogen gas to cool the
hydrogen gas before dispensing into the fuel tank of the HFCV.
SUMMARY
[0006] Some embodiments include a hydrogen gas fueling station
comprising a roadside unit positioned at the fueling station and
configured to communicate with a first on-board unit associated
with a first vehicle, and a first dispenser communicatively coupled
to the roadside unit and configured to dispense hydrogen gas via a
first nozzle, the first dispenser configured to provide first
nozzle information corresponding to the first nozzle to the first
vehicle when the first vehicle has engaged with the first nozzle,
wherein the roadside unit is configured to receive feedback from
the first vehicle responsive to the first nozzle identification
information via a first connection established with the first
on-board unit.
[0007] Some embodiments include method of performing
vehicle-to-nozzle pairing comprising establishing a first
connection between a roadside unit positioned at a fueling station
and a first on-board unit associated with a first vehicle, engaging
a first nozzle of a first dispenser with a first vehicle, providing
first nozzle information corresponding to the first nozzle to the
first vehicle, receiving feedback from the first vehicle responsive
to the first nozzle identification information via the first
connection, and associating the first connection with the first
nozzle based on the received feedback.
[0008] Some embodiments include a fueling station comprising a
roadside unit positioned at the fueling station and configured to
communicate with a plurality of on-board units associated with
respective vehicles via a respective wireless connection
established between the roadside unit and each of the plurality of
on-board units, and at least one controller configured to process
fueling information received via each respective wireless
connection and configured to cause at least one action to be
performed based on the received fueling information.
[0009] Some embodiments include a method comprising establishing a
wireless connection between a roadside unit positioned at a fueling
station and each of a plurality of on-board units associated with
respective vehicles, receiving fueling information via each
wireless connection, and performing at least one action at the
fueling station in response to the received fueling
information.
[0010] Some embodiments includes fueling station comprising a
roadside unit positioned at the fueling station and configured to
communicate with a plurality of on-board units associated with
respective vehicles via a respective wireless connection between
the roadside unit and each of the plurality of on-board units, and
at least one controller coupled to the roadside unit, the at least
one controller configured to process fueling information received
via each respective wireless connection and configured to cause at
least one action to be performed based on an expected refueling
demand determined from the received fueling information.
[0011] Some embodiments include a method comprising establishing a
wireless connection between a roadside unit positioned at a fueling
station and each of a plurality of on-board units associated with
respective vehicles, receiving fueling information via each
wireless connection, and performing at least one action at the
fueling station based on an expected refueling demand determined
from the received fueling information.
[0012] Some embodiments include a fueling station comprising a
roadside unit positioned at the fueling station and configured to
communicate with a first on-board unit associated with a first
vehicle via a first wireless connection established between the
roadside unit and the on-board unit, and at least one controller
configured to receive a nozzle reservation request via the first
wireless connection and configured to negotiate a nozzle
reservation via the first wireless connection.
[0013] Some embodiments include a method comprising establishing a
wireless connection between a roadside unit positioned at a fueling
station and a first on-board unit associated with a first vehicle,
receiving a nozzle reservation request via the first wireless
connection, and negotiating a nozzle reservation via the first
wireless connection.
[0014] Some embodiments include a fueling station comprising a
first roadside unit positioned at the fueling station and
configured to communicate with a plurality of on-board units
associated with respective vehicles via a respective wireless
connection between the roadside unit and each of the plurality of
on-board units, and at least one controller coupled to the first
roadside unit, the at least one controller configured to process
fueling information received from the roadside unit via each
respective wireless connection, determine status information
indicative of refueling capability of the fueling station, and
provide the status information to at least one of the plurality of
on-board units via the respective wireless connection.
[0015] Some embodiments include a method comprising establishing a
wireless connection between a roadside unit positioned at a fueling
station and each of a plurality of on-board units associated with
respective vehicles, receiving fueling information received via
each respective wireless connection, determining status information
indicative of refueling capability of the fueling station, and
providing the status information to at least one of the plurality
of on-board units via the respective wireless connection.
[0016] Some embodiments include a hydrogen cooling system
comprising a large-volume reservoir for holding coolant, a
small-capacity refrigeration unit coupled to the large-volume
reservoir to reduce a temperature of coolant held in the
large-volume reservoir, and a heat exchanger configured to
thermally couple coolant held by the large-volume reservoir to
hydrogen gas flowing through the heat exchanger via heat exchange
with the coolant.
[0017] Some embodiments include a hydrogen cooling system
comprising a large-volume reservoir for holding coolant, a
small-capacity refrigeration unit fluidly coupled to the
large-volume reservoir to reduce the temperature of coolant held in
the large-volume reservoir, and a heat exchanger fluidly coupled to
the large-volume reservoir and a hydrogen gas source, the heat
exchanger configured to cool hydrogen gas from the hydrogen gas
source using coolant from the large-volume reservoir.
[0018] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configured to dispense
hydrogen gas via a second nozzle, a large-volume reservoir for
holding coolant, a small-capacity refrigeration unit coupled to the
large-volume reservoir to reduce a temperature of coolant held in
the large-volume reservoir, a first heat exchanger coupled to the
large-volume reservoir and configured to chill hydrogen gas via
heat transfer with coolant held by the large-volume reservoir and
provide chilled hydrogen gas to the first dispenser for dispensing
via the first nozzle, and a second heat exchanger coupled to the
large-volume reservoir and configured to chill hydrogen gas via
heat transfer with coolant held by the large-volume reservoir and
provide chilled hydrogen gas to the second dispenser for dispensing
via the second nozzle.
[0019] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configure to dispense
hydrogen gas via a second nozzle, a large-volume reservoir for
holding coolant, a small-capacity refrigeration unit coupled to the
large-volume reservoir to reduce a temperature of coolant held in
the large-volume reservoir, and a first heat exchanger coupled to
the large-volume reservoir and configured to chill hydrogen gas via
heat transfer with coolant held by the large-volume reservoir and
provide chilled hydrogen gas to the first dispenser for dispensing
via the first nozzle and to the second dispenser for dispensing via
the second nozzle.
[0020] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configure to dispense
hydrogen gas via a second nozzle, a first large-volume reservoir
for holding coolant, a second large-volume reservoir for holding
coolant, a small-capacity refrigeration unit coupled to the first
large-volume reservoir and the second large-volume reservoir to
reduce a temperature of coolant held in the first large-volume
reservoir and the second large-volume reservoir, a first heat
exchanger coupled to the large-volume reservoir and configured to
chill hydrogen gas via heat transfer with coolant held the first
large-volume reservoir and provide chilled hydrogen gas to the
first dispenser for dispensing via the first nozzle, and a second
heat exchanger coupled to the second large-volume reservoir and
configured to chill hydrogen gas via heat transfer with coolant
held by the second large-volume reservoir and provide chilled
hydrogen gas to the second dispenser for dispensing via the second
nozzle.
[0021] Some embodiments include a hydrogen cooling system
comprising a first reservoir comprising a first tank configured to
hold first coolant comprising at least one phase-change material, a
refrigeration unit coupled to the first reservoir to chill the
first coolant to cause the phase-change material held by the first
tank to change from a first state to a second state, and a first
heat exchanger configured to thermally couple the first coolant
held by the first reservoir to hydrogen gas flowing through the
heat exchanger via heat exchange with the first coolant.
[0022] Some embodiments include a hydrogen cooling system
comprising a first reservoir comprising a first tank configured to
hold first coolant comprising at least one phase change material, a
second reservoir comprising second tank configured to hold second
coolant, a refrigeration unit coupled to the first reservoir to
chill the at least one phase change material to cause the phase
change material to change from a first state to a second state, and
coupled to the second reservoir to chill the second coolant, and a
first heat exchanger configured to thermally couple the first
coolant and hydrogen gas flowing through the heat exchanger to
chill the hydrogen gas to a first temperature via heat exchange
with the first coolant, and a second heat exchanger configured to
thermally couple the second coolant and the hydrogen gas chilled to
the first temperature to chill the hydrogen gas to a second
temperature via heat exchange with the second coolant and to
provide the chilled hydrogen gas to at least one first
dispenser.
[0023] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configured to dispense
hydrogen gas via a second nozzle, a large-volume reservoir for
holding coolant, a single small-capacity refrigeration unit fluidly
coupled to the large-volume reservoir to reduce the temperature of
coolant held in the large-volume reservoir, a first heat exchanger
fluidly coupled to the large-volume reservoir and a hydrogen gas
source, the first heat exchanger configured to provide cooled
hydrogen gas for dispensing by the first dispenser via the first
nozzle, and a second heat exchanger fluidly coupled to the
large-volume reservoir and a hydrogen gas source, the heat
exchanger configured to provide cooled hydrogen gas for dispensing
by the second dispenser via the second nozzle.
[0024] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configure to dispense
hydrogen gas via a second nozzle, a large-volume reservoir for
holding coolant, a small-capacity refrigeration unit fluidly
coupled to the large-volume reservoir to reduce the temperature of
coolant held in the large-volume reservoir, and a first heat
exchanger fluidly coupled to the large-volume reservoir and a
hydrogen gas source, the first heat exchanger configured to provide
cooled hydrogen gas to the first dispenser for dispensing via the
first nozzle and to the second dispenser for dispensing via the
second nozzle.
[0025] Some embodiments include a hydrogen fueling system
comprising a first dispenser configured to dispense hydrogen gas
via a first nozzle, a second dispenser configure to dispense
hydrogen gas via a second nozzle, a first large-volume reservoir
for holding coolant, a second large volume reservoir for holding
coolant, a small-capacity refrigeration unit fluidly coupled to the
first large-volume reservoir and the second large-volume reservoir
to reduce the temperature of coolant held in the first and second
large-volume reservoirs, a first heat exchanger fluidly coupled to
the first large-volume reservoir and a hydrogen gas source, the
first heat exchanger configured to provide cooled hydrogen gas for
dispensing by the first dispenser via the first nozzle, and a
second heat exchanger fluidly coupled to the second large-volume
reservoir and a hydrogen gas source, the heat exchanger configured
to provide cooled hydrogen gas for dispensing by the second
dispenser via the second nozzle.
[0026] Some embodiments include a hydrogen cooling system
comprising a first reservoir comprising a first tank holding at
least one phase change material, a refrigeration unit coupled to
the first reservoir to chill the at least one phase change material
to cause the phase change material held by the first tank to change
from a first state to a second state, and a first heat exchanger to
receive hydrogen from a hydrogen gas source and provide hydrogen
gas to at least one first dispenser, the first heat exchanger
coupled to the first reservoir to chill the hydrogen gas from the
hydrogen gas source to provide chilled hydrogen to the at least one
first dispenser.
[0027] Some embodiments include a hydrogen cooling system
comprising a first reservoir comprising a first tank configured to
hold first coolant comprising at least one phase-change material, a
second reservoir comprising a second tank configured to hold second
coolant, a refrigeration unit coupled to the first reservoir to
chill the at least one phase-change material to cause the at least
one phase-change material to change from a first state to a second
state, and coupled to the second reservoir to chill the second
coolant, a first heat exchanger configured to thermally couple the
first coolant and hydrogen gas flowing through the first heat
exchanger to chill the hydrogen gas to a first temperature via heat
exchange with the first coolant, and a second heat exchanger
configured to thermally couple the second coolant and the hydrogen
gas chilled to the first temperature to chill the hydrogen gas to a
second temperature via heat exchange with the second coolant and to
provide the chilled hydrogen gas to at least one first
dispenser.
[0028] Some embodiments include a hydrogen cooling system
comprising a first reservoir comprising a first tank holding at
least one phase change material, a second reservoir comprising
second tank holding at least one non-phase change coolant, a
refrigeration unit coupled to the first reservoir to chill the at
least one phase change material to cause the phase change material
held by the first tank to change from a first state to a second
state, and coupled to the second reservoir to chill the at least
one non-phase change coolant, a first heat exchanger to receive
hydrogen from a hydrogen gas source, the first heat exchanger
coupled to the first reservoir to chill the hydrogen gas to a first
temperature via heat exchange with the at least one phase change
material, and a second heat exchanger to receive the hydrogen gas
at the first temperature from the first heat exchanger, the second
heat exchanger coupled to the second reservoir to chill the
hydrogen gas via heat exchange with the at least one non-phase
change material to chill the hydrogen gas to a second temperature
and provide the hydrogen gas to at least one first dispenser.
[0029] Some embodiments include an annular heat exchanger
comprising a shell having a coolant inlet and a coolant outlet, at
least one coil comprising nickel alloy tubing concentrically
arranged within the shell, the at least one coil having a hydrogen
inlet and a hydrogen outlet, and a plurality of copper fins brazed
to the at least one nickel alloy coil using silver or silver alloy,
wherein the annular heat exchanger is configured to chill hydrogen
gas that is caused to flow through the at least one coil via the
hydrogen inlet and the hydrogen outlet by heat exchange with
coolant that is caused to circulate through the shell via the
coolant inlet and the coolant outlet.
[0030] Some embodiments include annular heat exchanger comprising a
shell having a coolant inlet and a coolant outlet, at least one
coil comprising tubing concentrically arranged within the shell,
the tubing having a wall thickness between 0.03 and 0.06 inches and
a length between 30 and 50 feet, the at least one coil further
comprising a hydrogen inlet and a hydrogen outlet and having
between 20 and 35 turns, and a plurality of fins attached to the at
least one coil, wherein the annular heat exchanger is configured to
chill hydrogen gas that is caused to flow through the at least one
coil via the hydrogen inlet and the hydrogen outlet via heat
exchange with coolant that is caused to circulate through the shell
via the coolant inlet and the coolant outlet.
[0031] Some embodiments include a hydrogen gas dispenser configured
to receive hydrogen gas from a hydrogen gas supply and provide the
hydrogen gas to a fuel tank of a vehicle during a fueling event,
the hydrogen gas dispenser comprising at least one nozzle
configured to engage with the fuel tank to dispense hydrogen gas to
the fuel tank during the fueling event, a valve bank comprising a
plurality of fixed-size orifice valves arranged in parallel, the
bank configured to receive hydrogen gas from the hydrogen gas
supply and to deliver hydrogen gas passing through one or more of
the plurality of fixed-size orifice valves that have been opened,
and a dispenser controller coupled to the bank and configured to
selectively open or close the plurality of fixed-size orifice
valves to deliver gas at desired target pressures and/or target
flow rates to the at least one nozzle.
[0032] Some embodiments include a hydrogen gas dispenser configured
to receive hydrogen gas from a hydrogen gas supply and provide the
hydrogen gas to a fuel tank of a vehicle during a fueling event,
the hydrogen gas dispenser comprising at least one nozzle
configured to engage with the fuel tank to dispense hydrogen gas to
the fuel tank during the fueling event, a variable-size valve
comprising a valve stem that when rotated changes a size of the
valve opening, the variable-size valve coupled to receive hydrogen
gas from the hydrogen gas such that changing the size of the valve
opening results in a change in a flow rate of hydrogen gas passing
through the valve opening, a direct drive servo motor coupled to
the valve stem of the variable-size valve, the direct drive servo
motor configured to rotate the valve stem to change the size of the
valve opening, wherein one rotation of the direct drive servo motor
results in one rotation of the valve stem, and a dispenser
controller coupled to the direct drive servo motor and configured
to cause the direct drive servo motor to rotate to change the size
of the valve opening to provide hydrogen gas at desired flow rates
based on target pressures and/or target flow rates of the fuel tank
of the vehicle during the fueling event.
[0033] Some embodiments include coaxial tubing for piping hydrogen
gas between components of a hydrogen fueling station, the coaxial
tubing comprising inner tubing configured to allow hydrogen gas to
be piped between one or more components of the hydrogen fueling
station, middle tubing arranged concentrically about the inner
tubing such that when phase change material is contained in the
middle tubing, the phase change material is positioned to thermally
couple to hydrogen gas flowing through the inner tubing, and outer
tubing arranged concentrically about the middle tubing such that
when coolant is conveyed through the outer tubing, the coolant
thermally couples to the phase-change material when present.
[0034] Some embodiments include a hydrogen fueling system
comprising coaxial tubing comprising inner tubing configured to
allow hydrogen gas to be piped between one or more components of
the hydrogen fueling station, middle tubing arranged concentrically
about the inner tubing so that a phase change material contained in
the middle tubing thermally couples to hydrogen gas flowing through
the inner tubing, and outer tubing arranged concentrically about
the middle such that when coolant is conveyed through the outer
tubing, the coolant thermally couples to the phase-change material
contained in the middle tubing, and a chiller system configured to
chill coolant to a temperature sufficient to cause a state
transition of the phase-change material, the chiller system coupled
to the coaxial tubing to convey chilled coolant through the outer
tubing to cause the state transition of the phase-change material
contained in the middle tubing.
BRIEF DESCRIPTION OF DRAWINGS
[0035] Various aspects and embodiments of the disclosed technology
will be described with reference to the following figures. It
should be appreciated that the figures are not necessarily drawn to
scale. Items appearing in multiple figures are indicated by the
same reference number in all the figures in which they appear.
[0036] FIG. 1 illustrates a block diagram of an exemplary hydrogen
gas dispensing system including a fueling station and a vehicle
communicatively coupled to the fueling station, in accordance with
some embodiments;
[0037] FIG. 2A illustrates a plurality of vehicles in-range and
out-of-range of a fueling station, in accordance with some
embodiments;
[0038] FIG. 2B illustrates a plurality of vehicles within a zone of
communication of a fueling station, in accordance with some
embodiments;
[0039] FIG. 3 illustrates a vehicle hopping technique, in
accordance with some embodiments;
[0040] FIG. 4A illustrates an exemplary communication sequence
between a fueling station and one or more vehicles, in accordance
with some embodiments;
[0041] FIG. 4B illustrates an exemplary method of taking action at
a fueling station based on fueling information received via a
controller area network, in accordance with some embodiments;
[0042] FIG. 4C illustrates an exemplary method of performing nozzle
reservation via a controller area network, in accordance with some
embodiments;
[0043] FIG. 5 illustrates a block diagram of an exemplary hydrogen
gas dispensing system including a fueling station and a plurality
of vehicles communicatively coupled to the fueling station, in
accordance with some embodiments;
[0044] FIG. 6 illustrates a method of performing vehicle-to-nozzle
pairing, in accordance with some embodiments;
[0045] FIG. 7 illustrates a method of performing vehicle-to-nozzle
pairing comprising electrically transmitting a nozzle
identification to a vehicle, in accordance with some
embodiments;
[0046] FIG. 8 illustrates a block diagram of an exemplary gas
dispensing system using the vehicle-to-nozzle pairing method
illustrated in FIG. 7, in accordance with some embodiments;
[0047] FIG. 9 illustrates a method of performing vehicle-to-nozzle
pairing comprising delivering a flow signature to a vehicle, in
accordance with some embodiments, in accordance with some
embodiments;
[0048] FIG. 10 illustrates a method of performing vehicle-to-nozzle
pairing comprising electrically transmitting a nozzle
identification and delivering a flow signature to a vehicle, in
accordance with some embodiments;
[0049] FIG. 11 illustrates a hydrogen cooling system comprising a
refrigeration unit, coolant reservoir and high UA heat exchanger,
in accordance with some embodiments;
[0050] FIG. 12 illustrates an exemplary process for maintaining and
recovering a target temperature of coolant in a hydrogen cooling
system configured for hydrogen gas refueling, in accordance with
some embodiments;
[0051] FIG. 13 is a plot of recovery times as a function of
refrigeration unit (chiller) capacity at three different ambient
temperatures using a 100-gallon tank as the coolant reservoir;
[0052] FIGS. 14A-E illustrate aspects of an annular high UA heat
exchanger for hydrogen refueling using a shell-and-tube
configuration, in accordance with some embodiments;
[0053] FIG. 15 illustrates a coil for an annular high UA heat
exchanger that has been finned to increase the heat transfer
efficiency of the coil, in accordance with some embodiments;
[0054] FIGS. 16A-F illustrate different configurations for an
annular high UA heat exchanger, in accordance with some
embodiments;
[0055] FIG. 17 illustrates a hydrogen cooling system comprising a
refrigeration unit having an integrated coolant reservoir, in
accordance with some embodiments;
[0056] FIG. 18 illustrates a hydrogen cooling system configuration
in which a refrigeration unit provides cooling to a coolant
reservoir shared by multiple dispensers, each dispenser coupled to
a respective heat exchanger, in accordance with some
embodiments;
[0057] FIG. 19 illustrates a hydrogen cooling system configuration
in which a refrigeration unit provides cooling to a coolant
reservoir shared by multiple dispensers that share a heat
exchanger, in accordance with some embodiments;
[0058] FIG. 20 illustrates a hydrogen cooling system configuration
in which a refrigeration unit provides cooling to multiple coolant
reservoirs and heat exchangers coupled to respective dispensers, in
accordance with some embodiments;
[0059] FIG. 21 illustrates a hydrogen cooling system utilizing
phase change material (PCM) to increase the thermal energy capacity
of a coolant reservoir, in accordance with some embodiments;
[0060] FIG. 22 illustrates a dual-stage hydrogen cooling system
comprising a bulk PCM reservoir and a polishing reservoir, in
accordance with some embodiments;
[0061] FIG. 23 illustrates an annular heat exchanger configured to
hold PCM for hydrogen cooling, in accordance with some
embodiments;
[0062] FIG. 24 illustrates a hydrogen cooling system utilizing
annular heat exchanger configured to hold PCM for hydrogen cooling,
in accordance with some embodiments;
[0063] FIG. 25 illustrates a hydrogen cooling system comprising a
refrigeration unit have an integrated coolant reservoir configured
to contain both PCM and conventional coolant, in accordance with
some embodiments;
[0064] FIG. 26A illustrates coaxial tubing that integrates PCM and
conventional coolant to provide hydrogen cooling, in accordance
with some embodiments;
[0065] FIG. 26B illustrates an exemplary hydrogen fueling system
employing the coaxial tubing illustrated in FIG. 26A;
[0066] FIG. 27 illustrates the pressure profile of an exemplary
fueling protocol;
[0067] FIG. 28 illustrates a hydrogen dispenser comprising a bank
of fixed-size orifice valves to control the flow rate of hydrogen
gas, in accordance with some embodiments;
[0068] FIG. 29 illustrates a method for performing a fueling event
employing a bank of fixed-size orifice, in accordance with some
embodiments;
[0069] FIG. 30 illustrates a dual-nozzle dispenser employing a bank
of fixed-size orifice, in accordance with some embodiments;
[0070] FIG. 31 illustrates a hydrogen dispenser comprising a flow
control valve having a direct drive servo motor paired with a
variable-size orifice valve, in accordance with some
embodiments;
[0071] FIG. 32 illustrates a method for performing a fueling event
employing a flow control valve having a direct drive servo motor
paired with a variable-size orifice valve, in accordance with some
embodiments; and
[0072] FIGS. 33A and 33B illustrate views of a flow control valve
having a direct drive servo motor paired with a variable-size
orifice valve, in accordance with some embodiments.
DETAILED DESCRIPTION
[0073] Existing communication between a vehicle and a hydrogen
fueling station is generally limited to a LOS link between the
vehicle and the hydrogen dispenser, conventionally implemented
using a one-way IrDA connection established between an infrared
transmitter disposed near the vehicle's fuel tank and an infrared
receiver on the dispenser nozzle brought into close proximity when
the nozzle is inserted into the vehicle's fuel tank. Once this
unidirectional communication link is established, the vehicle can
transmit fueling parameters such as tank volume and current tank
conditions such as tank pressure and temperature. This conventional
approach has a number of drawbacks recognized by the inventors,
including limited bandwidth, unidirectionality, equipment
reliability and cost (approximately $3K per nozzle), etc.
[0074] The inventors have recognized that vehicle-to-vehicle and
vehicle-to-infrastructure communications, referred to as V2X, can
be employed to expand the communication capabilities between
vehicles and hydrogen fueling stations to improve the refueling
process in a number of ways, including providing a higher
bandwidth, bi-directional communication channel capable of safely
and securely exchanging a much richer set of data between vehicles
and fueling stations. According to some embodiments, a vehicle is
equipped with an on-board unit (OBU) configured to wirelessly
communicate with a road-side unit (RSU) located at a fueling
station to exchange, among other data, fueling parameters, status
information on the fueling station, and the like.
[0075] The inventors have further developed techniques to determine
which vehicle is engaged with which nozzle at a fueling station, a
process referred to as vehicle-to-nozzle pairing. As discussed
above, conventional systems employed an IrDA communication link
between a vehicle and a dispenser established between an IrDA
transmitter disposed proximate the vehicle's fuel and tank and an
IrDA receiver (typically a circular array of IrDA receivers)
disposed on the nozzle dispenser. Because an IrDA link could only
be established between a nozzle and the vehicle to which the nozzle
was engaged, there was no ambiguity to resolve. However, in a V2X
wireless network, a fueling station may communicate with numerous
vehicles within a zone of communication of the fueling station. As
a result, the fueling station typically needs to resolve which
vehicle is engaged at a given nozzle prior to performing a
refueling event. According to some embodiments, vehicle-to-nozzle
pairing comprises providing nozzle information to a vehicle and
receiving feedback from the vehicle via a wireless connection
(e.g., a V2X connection) in response to receiving the nozzle
information via a V2X connection established between the fueling
station and the vehicle. The feedback from the vehicle may be used
to associate the nozzle with the wireless connection to perform
vehicle-to-nozzle pairing. The inventors have also recognized the
importance of allowing refueling events to be performed
anonymously. To ensure that vehicle anonymity can be maintained,
the inventors have developed vehicle-to-nozzle pairing techniques
and refueling processes that do not require a vehicle to provide
information that identifies the vehicle or its operator, examples
of which are described in further detail below.
[0076] Following below are further detailed descriptions of various
concepts related to, and embodiments of, vehicle communication
systems and methods for facilitating refueling of hydrogen fuel
cell vehicles. It should be appreciated that the embodiments
described herein may be implemented in any of numerous ways.
Examples of specific implementations are provided below for
illustrative purposes only. It should be appreciated that the
embodiments and the features/capabilities provided may be used
individually, all together, or in any combination of two or more,
as aspects of the technology described herein are not limited in
this respect.
[0077] FIG. 1 illustrates an exemplary system in which a fueling
station is configured to communicate with a vehicle via wireless
connection established between the vehicle and the fueling station
(e.g., via wireless V2X communication). System 1000 comprises a
hydrogen fuel cell vehicle (HFVC) 1100 having at least one hydrogen
fuel tank 1110 for storing hydrogen gas used to power vehicle 1100.
Vehicle 1100 is also equipped with an engine control module (ECM)
1160 (e.g., the vehicle's computer system) configured to obtain and
monitor tank parameters of the hydrogen fuel tank(s) 1110. ECM 1160
is communicatively coupled to on-board unit (OBU) 1150 to allow
wireless connections to be established between other vehicles and
infrastructure, such as fueling station 1200. OBU 1150 includes one
or more transceivers configured to transmit and receive information
wirelessly, for example, to communicate with roadside units, other
OBUs, or any other devices configured for wireless communications
(e.g., mobile devices such as smart phones, navigation systems,
etc.). OBU 1150 is typically mounted in or on the car or may be,
alternatively, a mobile unit that can be positioned to
communicatively couple with ECM 1160.
[0078] Fueling station 1200 comprises one or more hydrogen
dispensers (e.g., dispensers 1220a, 1220b, etc.) that dispense
hydrogen fuel stored at and/or generated by fueling station 1200
via nozzles (e.g., nozzles 1225a, 1225b, etc.) configured to engage
with the fuel tank of an HFVC. Fueling station 1200 further
comprises road-side unit (RSU) 1250 (alternatively referred to as a
wayside unit) configured to communicate with vehicles equipped with
an OBU (e.g., vehicle 1110 equipped with OBU 1150). RSU 1250 also
includes one or more transceivers configured to transmit and
receive information wirelessly, for example, to communicate with
OBUs, other RSU's or any other devices configured for wireless
communications. RSU may be coupled to one or more controllers
(e.g., one or more processors, chips or chip sets, programmable
logic controllers, systems-on-chip (SOC), etc.) configured to
perform any one or combination of vehicle communication techniques
described herein. As used herein, an RSU coupled to one or more
controllers refers to communicative coupling between any of the
controllers that are part of the RSU (e.g., on-unit processors,
co-processors, PLC's, etc.) and/or any controllers that are
communicatively coupled to the RSU (e.g., via a wired or wireless
communication link) at the fueling station. Furthermore, acts
described herein as being performed by the RSU refer to acts
performed by the RSU and/or any controller to which the RSU is
coupled at the fueling station.
[0079] In the embodiment illustrated in FIG. 1, RSU 1250 is
connected to a network at the fueling station (e.g., via a station
PLC or network switch) to allow information exchange between RSU
1250 and the dispensers or other components of fueling station
1200. System 1000 allows V2X communication between vehicle 1100 and
fueling station 1200 by establishing a wireless connection 1050
between OBU 1150 and RSU 1250 over which information may be
exchanged (e.g., fueling information such as tank parameters, fuel
availability, navigation information, payment information,
etc.).
[0080] According to some embodiments, V2X communication may be
accomplished using the 5.9 GHz band allocated for dedicated
short-range communication (DSRC). However, V2X may implemented in
other ways such as via 4G, 5G, 802.11x or using other suitable
standards and/or protocols operating in the same or different radio
frequency bands, as the aspects are not limited to any particular
type of V2X communication. Wireless connection 1050 does not
require LOS so that fueling station 1200, via RSU 1250, can
broadcast and/or exchange data with any OBU with which a connection
has been established that is within range of RSU 1250 (e.g., within
a kilometer of the fueling station), or within a larger zone of
communication using a vehicle hopping technique, examples of which
are described in further detail below. It will be understood that
fueling station is illustrated to show schematically a exemplary
communication coupling of certain components of the fueling
station, and that fueling station may include other components not
illustrated, such as hydrogen cooling systems (e.g., any of the
exemplary hydrogen cooling systems described herein).
[0081] FIG. 2A illustrates an example environment in which RSU 1250
employed at fueling station 1200 can communicate with multiple
vehicles (e.g., vehicles 1100a-1100d) within range of the RSU
(denoted schematically as range 1255). The range of the RSU will
depend in part on the frequency band used by the RSU to communicate
with OBUs and regulatory limits on that frequency band (e.g., power
requirements limiting transmission power, etc.), and may range from
tens to hundreds of yards to a kilometer or more. For example,
according to some embodiments, RSUs and OBUs operate in the 5.9 GHz
band (5.850-5.925 GHz band) allocated for DSRC, which can provide
ranges on the order of a kilometer or more. According to some
embodiments, OBUs and RSUs operate in the 5.9 GHz band and are IEEE
1609, IEEE 802.11P and SAE J2735 compliant to facilitate safe and
secure exchange of information, further details of which are
discussed below.
[0082] In FIG. 2A, vehicles 1100a-d are within range of RSU 1250
and can communicate with fueling station 1200 via the vehicle's
respective OBU. Vehicle 1100a, for example, may be at the fueling
station and vehicles 1100b-d may be on the road or otherwise
located within range of RSU 1250. Typically, RSUs and OBUs exchange
security information (e.g., digitally signed certificates) to
ensure that a given RSU and OBU are authorized to exchange
information and to authenticate the units at both ends of an
exchange. Once a connection is established, the OBU can securely
transmit tank information to the RSU such as tank volume,
receptacle type, fueling commands, measure pressured and
temperature information and/or additional information about the
vehicle (e.g., location). Fueling station 1200 may transmit
information to vehicles via established connections between RSU
1250 and corresponding OBUs, such as status information regarding
fuel availability, current wait times, fueling station location,
etc. Additional information such as nozzle reservation information,
navigation directions, etc., may be exchanged between the fueling
station and the vehicles within range 1255, some examples of which
are discussed in further detail below.
[0083] According to some embodiments, establishing wireless
connections and information exchange occur in a wireless access in
vehicular environment (WAVE) that enables safe and secure
communications between RSUs and OBUs, as discussed in further
detail in Appendix A of U.S. Provisional Application No. 63/131,953
('953 Provisional) incorporated by reference herein. Alternatively,
or in addition to, other wireless communication channels and
protocols may be used to establish connections and exchange
information between a fueling station and vehicles within a zone of
communication of the fueling station, some further examples of
which are described in Appendix A of the '953 Provisional.
[0084] The V2X environment illustrated in FIG. 2A may be used to
establish a controller area network (CAN) that allows fueling
station 1200, via RSU 1250, to communicate with multiple vehicles
to obtain fueling parameters to inform a refueling event, collect
data that facilitates predicting the demand on the fueling station
based on the fueling needs of vehicles in the area, advise vehicles
as to optimal timing and/or location for a refueling event,
schedule a refueling event, etc. According to some embodiments,
information exchanged via the CAN may be used to implement further
functionality such as establishing automatic payment, providing
navigation guidance to fueling stations, transmitting fueling
station availability, performing nozzle reservation, etc. For
example, by evaluating tank information received from multiple
in-range vehicles, fueling station can predict near-term demand and
take one or more actions at the fueling station in response, such
as powering down certain components of the fueling station (e.g.,
one or more components of a hydrogen cooling system) to save on
power consumption, optimizing filling of storage tanks to better
handle expected fueling events, model usage trends over time,
establish peak demand, low demand and/or average demand metrics,
etc., examples of which are described in further detail below.
[0085] According to some embodiments, a fueling station can
communicate with vehicles that are out-of-range using a technique
referred to herein as vehicle hopping by which messages between a
fueling station and a destination vehicle may be routed through one
or more intermediary vehicles. For example, FIG. 3 schematically
illustrates an exemplary CAN 3000 comprising RSU 3250 at a fueling
station 3200 and a plurality of OBUs 3150a-e deployed in respective
vehicles 3100a-e. In exemplary CAN 3000, vehicle 3100a is within
range of RSU 3250 and has established a direct connection 3050a
with OBU 3150a. Vehicles 3100b and 3100c are within range of
vehicle 3100a and direct connections 3050b and 3050c have been
established between OBU 3150a and OBUs 3150b and 3150c,
respectively. Vehicle 3100d is within range of vehicle 3100b and a
direct connection 3050d has been established between OBU 3150b and
OBU 3150d. Similarly, vehicle 3100e is within range of vehicle
3100c and direction connection 3050e has been established between
OBU 3150c and OBU 3150e.
[0086] The direct connections established in CAN 3000 can be
utilized to establish an indirect connection between RSU 3250 and
any of the OBUs in the network, even those that are not within
range of RSU 3250. According to some embodiments, established
direct connections are used as pass-throughs that enable RSU 3250
to establish an indirect connection and thereafter route messages
to and receive messages from any of the OBUs in the network via
secure indirect connections. According to some embodiments, the
communication protocol allows for the same security features to be
used to ensure that indirect connections are also safe and secure
(e.g., authorized and authenticated). After an indirect connection
is established, information can be exchanged via this indirect
connection by routing messages from vehicle to vehicle until the
messages reach the specified destination.
[0087] By using vehicle hopping techniques, a fueling station can
expand its zone of communication to exchange information with
vehicles over a wider geographic area. For example, FIG. 2B
illustrates the environment illustrated in FIG. 2A in which
vehicles 1100a-d are within range 1255 of RSU 1250 and wireless
connections have been established between RSU 1250 and each
in-range vehicle. However, in the example schematically illustrated
in FIG. 2B, the fueling station's zone of communication has been
expanded to allow RSU 1250 to exchange information with
out-of-range vehicles 1100e-k using vehicle hopping techniques. For
example, vehicles 1100e and 1100h are within range 1155b of vehicle
1100b and direct connections are established between the OBUs of
the respective vehicles. RSU 1250 can therefore establish an
indirect connection with vehicles 1100e and 1100h to transmit
messages to and receive messages from vehicles 1100e and 1100h by
routing messages through vehicle 1100b. Similarly, vehicles 1100i
and 1100j are within range 1155e of vehicle 1100e and direct
connections are established between the OBUs of the respective
vehicles and RSU 1250 can establish an indirect connection with
vehicles 1100i and 1100j by vehicle hopping via vehicles 1100b and
1100e. Indirect connections can likewise be established between RSU
1250 and vehicle 1100k by vehicle hopping from vehicle 1100b to
1100h, and between RSU 1250 vehicle 1100g and 1100f by vehicle
hopping via vehicle 1100d. Thus, RSU 1250 can communicate with
vehicles over a larger geographic area to expand the reach of
fueling station 1200 (e.g., to form a larger CAN 2000), which can
in turn improve the fueling station's ability to predict demand,
can allow for a richer set of data to be obtained and/or may
facilitate providing services to a larger set of vehicles.
[0088] FIG. 4A illustrates an exemplary V2X communication sequence,
in accordance with some embodiments. Act 1410 comprises
establishing a wireless connection between an RSU located at a
fueling station and an OBU of a vehicle. The connection process,
also referred to herein as OBU/RSU pairing, may be initiated either
by an OBU transmission received by the RSU or a via an RSU
broadcast to OBUs within range. As discussed above, in
consideration of privacy considerations, some embodiments employ a
communication architecture that allows for a secure connection to
be established (and subsequent messages to be exchanged) while
preserving vehicle anonymity. For example, the above-mentioned WAVE
architecture enables OBUs to establish authorized and authenticated
connections with RSUs without requiring vehicle specific
identification information to be relayed to the fueling station. In
this way, V2X communications can be implemented while maintaining
the privacy of the vehicle and its operator. According to some
embodiments, upon the express or implied consent of the vehicle
operator, information identifying the vehicle or the vehicle
operator may be exchanged to allow certain services to be provided,
such as automatic payment, nozzle reservation, etc., as discussed
in further detail below.
[0089] Referring again to act 1410, to establish a wireless
connection, an OBU and an RSU may exchange security information
(e.g., signed digital certificates) confirming that the OBU and RSU
are both authorized to establish a connection and to authenticate
the OBU and RSU devices. The specifics of the security information
exchange will depend on the protocol supporting the V2X
communication. According to some embodiments, the V2X communication
is a DSRC connection that complies with, for example, IEEE 1609,
IEEE 802.11P, SAE J2735 and/or any of the protocols discussed in
the '953 Provisional, and the security information exchange is
implemented via WAVE. Once a connection has been established, data
can be securely exchanged between the OBU and the RSU. As discussed
above, some embodiments implement OBU/RSU pairing without requiring
vehicle or vehicle operator identification, thereby allowing a
secure connection to be established and subsequent data exchange to
be conducted while maintaining vehicle anonymity.
[0090] Act 1420 comprises exchanging data between the OBU and RSU
over the established connection. In many conventional systems,
information exchange between a vehicle and a fueling station was
limited to data that could be transmitted over a IrDA link, which
was limited not only in bandwidth but was also typically limited to
unidirectional transmission of data from the vehicle to the
dispenser nozzle. Establishing a V2X connection allows a richer set
of information to be exchanged between a vehicle and a fueling
station. For example, conventional IrDA links were sufficient for
transmitting a minimum set of tank parameters needed by the fueling
station to refuel the vehicle. According to some embodiments, a V2X
connection has orders of magnitude higher bandwidth, allowing for
significantly more information to be exchanged bi-directionally
between a fueling station and a vehicle. According to some
embodiments, the RSU at a fueling station (e.g., RSU 1250) may
obtain tank information from the vehicle via the OBU over the
established connection in real-time or near real-time.
[0091] As discussed above, some embodiments of a V2X communication
system allow for a many-to-many connections to be established
(e.g., an RSU may establish a direct connection with a plurality of
OBU within range of the RSU and/or may establish an indirect
connection with one or more out-of-range OBUs via vehicle hopping,
as discussed above in connection with the exemplary embodiments
illustrated in FIGS. 2A, 2B and 3). Accordingly, acts 1410 and 1420
may be repeated to establish secure connections (direct or
indirect) between a fueling station and multiple vehicles within a
zone of communication of the RSU at the fueling station. As a
result, information can be exchanged between a fueling station, via
its RSU, and multiple vehicles that can be used to improve service
at the fueling station.
[0092] Act 1430 comprises performing one or more actions at the
fueling station based at least in part on information exchanged
between the RSU and one or more OBUs associated with vehicles
within the zone of communication of the fueling station. According
to some embodiments, a fueling station may obtain tank information
from multiple vehicles in the vicinity and evaluate the information
to perform one or more predictive actions at the fueling station
based on an expected demand at the fueling station. For example,
information exchanged in act 1420 may indicate that several
vehicles in the vicinity are low on fuel and will likely need to
refuel at the station in the near-term. In response, the fueling
station may evaluate the status of the fueling systems (e.g.,
assess the current capacity of the fueling station to deliver
hydrogen fuel at certain temperature levels). On the other hand,
information exchanged in act 1420 may suggest that there are no
HFCVs in the area or that those that are within range of the
fueling station are not currently in need of refueling. Based on
the predicted demand, fueling station 1200 can ready itself to best
meet the predicted demand (e.g., power up or power down certain
components of the fueling station such as components of the
hydrogen fueling station), alert vehicles in the vicinity as to
status, wait times, etc., prepare for future fueling demands at the
fueling station and/or identify trends or patterns in fueling
demands to optimize the ability of the fueling station to meet
fueling demands throughout the day.
[0093] The inventors have developed a number of predictive
techniques and responsive operations to facilitate optimal fueling
station performance (i.e., to maximize availability and/or minimize
refueling times) to handle changing fueling demands throughout the
day, examples of which are discussed in further detail below. Any
one or combination of optimizations may be performed, including but
not limited to, minimizing energy consumption, maximizing fuel
availability, reducing refueling times, conducting dispenser
scheduling (e.g., nozzle reservations), ascertaining demand trends,
planning for peak demand hours, providing navigation information to
vehicles, redirecting vehicles to other fueling stations, etc.,
examples of which are discussed in further detail below.
[0094] The one or more actions performed at the fueling station may
include a fueling event in which the fueling station delivers fuel
to the tank of one of the vehicles. For example, the data exchanged
in act 1420 may include feedback from a vehicle to which a
dispenser nozzle has been engaged from which the fueling station
performs vehicle-to-nozzle pairing, examples of which are described
in connection with FIGS. 5-10 below. The data exchanged in act 1420
may also include tank information from the vehicle that the fueling
station uses to refuel the vehicle after the vehicle has been
paired with the nozzle engaged with the vehicle's fuel tank. Act
1440 comprises disconnecting the RSU and the OBU, which may be
performed with or without a fueling event with the vehicle. For
example, the RSU and an OBU may disconnect after the corresponding
vehicle has refueled, or the RSU and an OBU may disconnect when the
vehicle drives out-of-range or out of the zone of communication of
the RSU without the vehicle having come to and/or refueled at the
fueling station. In the latter case, for example, tank information
may be obtained from a vehicle in act 1420 indicating that the
vehicle has a full tank and the fueling station may use this
information to perform one or more predictive actions and may
subsequently disconnect with the OBU when the vehicle drives out of
range.
[0095] FIG. 5 illustrates a system 5000 comprising a fueling
station 2200 configured to refuel HFCVs and communicate with
vehicles within a zone of communication of the fueling station. At
an exemplary point in time, a first vehicle 1100a may be located at
fueling station 2200 prior to a fueling event and a plurality of
vehicles including vehicles 1100b and 1100c may be located within a
zone of communication of fueling station 2200. Fueling station 2200
includes RSU 2250, which may be similar to or the same as RSU 1250
described in connection with FIG. 1 (e.g., an RSU configured to
communicate with OBUs associated with vehicles within a zone of
communication of the RSU). In the example illustrated in FIG. 5,
wireless connections 2050a, 2050b and 2050c are established between
RSU 2250 and OBUs of respective vehicles 1100a, 1100b and
1100c.
[0096] Fueling station 2200 comprises a first dispenser 2220a and a
second dispenser 2220b configured to dispense hydrogen gas via a
first nozzle 2225a and second nozzle 2225b, respectively. While
exemplary dispensers 2220a and 2220b are shown having a single
nozzle, one or both of dispensers 2220a and 2220b may include
multiple nozzles via which hydrogen gas may be dispensed.
Furthermore, while exemplary fueling station 2200 is illustrated as
including two dispensers, some embodiments include fewer or
additional dispensers. For example, a fueling station may include
one single-nozzle or multi-nozzle dispenser or may include multiple
single-nozzle or multi-nozzle dispensers, as the aspects are not
limited to any particular configuration of dispensers and
nozzles.
[0097] In the embodiment illustrated in FIG. 5, dispensers 2220a-b
are communicatively coupled to RSU 2250 via station network
component 2210 (which may be the same as or similar to network
component 1210 described in connection with FIG. 1). In the
embodiment illustrated in FIG. 5, dispensers 2220a-b are fluidly
coupled to hydrogen storage component 2205 that stores hydrogen gas
to be dispensed by the dispensers through their respective nozzles.
According to some embodiments, the dispensers may also include
hydrogen storage within the dispenser or may be a standalone
appliance that produces, stores and dispenses hydrogen gas in a
self-contained dispenser appliance, some examples of which are
described in U.S. Pat. No. 10,236,522 titled "Hydrogen Gas
Dispensing Systems and Methods," which is herein incorporated by
reference in its entirety.
[0098] Wireless connections (e.g., wireless connections 2050a,
2050b and 2050c) may be established between RSU 2250 and the
respective OBU of any vehicle within the zone of communication of
the fueling station. For example, wireless connections 2050a and
2050b may be direct connections to vehicles 1100a and 1100b and
wireless connection 2050c may be an indirect connection to vehicle
1100c via vehicle 1100b using vehicle hopping techniques. Once a
wireless connection has been established, information can be
exchanged between vehicles and the various components of the
fueling station including, but not limited to, any one or
combination of fueling information (e.g., tank parameters), fueling
station status (e.g., hydrogen gas availability, predicted fill
times, etc.), navigation information, payment information, etc. In
exemplary system 5000, vehicle 1100a is located at fueling station
2200 for refueling. When nozzle 2225a is engaged with vehicle 1100
via fuel receptacle 1125, dispenser 2200a provides first nozzle
information 1025 corresponding to nozzle 2225a to the first
vehicle. Responsive to first nozzle information 1025, feedback from
vehicle 1100a is provided via wireless connection 2050a that the
fueling station can use to pair nozzle 2225a with vehicle 1100a to
initiate a fueling event.
[0099] Because RSU 2250 may have established wireless connections
with multiple vehicles (e.g., vehicle 1100b, 1100c, etc.), the
fueling station needs to resolve which vehicle has engaged with
which nozzle (e.g., the fueling station needs to identity which of
the vehicle that it is communicating with has engaged with the
nozzle so that it can ascertain which tank parameters belong the
vehicle engaged for refueling). By providing nozzle information and
receiving feedback responsive to the nozzle information,
vehicle-to-nozzle pairing can be performed without requiring the
vehicle to provide identification information specific to the
vehicle or the vehicle's operator. An exemplary method that allows
vehicle-to-nozzle pairing to be performed anonymously is described
below in connection with FIG. 6. It should be appreciated that a
vehicle may voluntarily provide identification information for the
vehicle or vehicle operator (e.g., to perform automatic payment),
but aspects of the inventors' contribution allow for
vehicle-to-nozzle pairing and the subsequent fueling event to be
performed anonymously without requiring such information.
[0100] FIG. 6 illustrates an exemplary method of performing
vehicle-to-nozzle pairing, in accordance with some embodiments.
Method 1600 may be performed, for example, in the context of the
system illustrated in FIG. 5. Act 1610 comprises establishing a
wireless connection between a fueling station and a vehicle. For
example, act 1610 may be performed by establishing a first
connection between an RSU positioned at the fueling station and a
first OBU associated with a first vehicle, such as a V2X connection
discussed above in connection with FIG. 4A. Act 1610 may be
performed to establish a wireless connection between the fueling
station and any vehicle within the zone of communication of the
fueling station (e.g., fueling station may establish one or more
direct connections and/or one or more indirect connections via
vehicle hopping). Accordingly, act 1610 may be repeated to
establish connections with any number of vehicles with a zone of
communication of the fueling station.
[0101] Act 1620 comprises engaging a dispenser nozzle with a
vehicle to begin a refueling process. For example, a vehicle
operator or fueling station personnel may attach a dispenser nozzle
to a fuel receptacle of the vehicle. Because a wireless connection
may be established with multiple vehicles in a zone of
communication of the fueling station, the fueling station may not
be able to ascertain which vehicle has engaged with the dispenser
nozzle. For example, a fueling station may obtain tank information
(e.g., tank size, measured tank pressure and temperature, etc.)
from multiple vehicles via respective wireless connections but be
unable to determine which information corresponds to the vehicle
that has engaged with the dispenser nozzle for refueling.
Accordingly, the fueling station may need to resolve the correct
pairing between dispenser nozzle and vehicle to safely and
correctly refuel the vehicle. At conventional fueling stations, a
dispenser nozzle could only receive tank information from the
vehicle to which the nozzle was engaged due to the LOS limitations
of the IrDA link over which this information is transmitted so that
vehicle-to-nozzle pairing was accomplished simply by engaging the
dispenser nozzle with the vehicle and establishing the IrDA
link.
[0102] Act 1630 comprises providing nozzle information
corresponding to the dispenser nozzle to the vehicle engaged with
the dispenser nozzle. Nozzle information may comprise information
of any type (or of multiple different types) and may be provided in
any suitable manner, such as transmitting nozzle information
electronically to the vehicle (e.g., via a low power radio
frequency transmitter, such as an RFID tag), delivering nozzle
information as a fluid flow signature (e.g., a hydrogen gas flow
pattern), or a combination of both, as discussed in further detail
below in connection with FIGS. 7-9. According to some embodiments,
at least some of the nozzle information provided in act 1630 is
changed or varied each time the nozzle is engaged with a vehicle.
In exemplary act 1630, nozzle information is provided via the
dispenser nozzle so that only the vehicle engaged with the
respective dispenser nozzle receives the nozzle information so that
the corresponding vehicle-to-nozzle pairing can be correctly
resolved.
[0103] Act 1640 comprises receiving feedback from the vehicle
responsive to the nozzle identification information via the
wireless connection. The feedback from the vehicle will depend on
the manner in which nozzle information was provided to the vehicle.
For example, the nozzle information may include a nozzle ID (e.g.,
a nozzle ID number) provided to the vehicle (e.g., electronically)
that the vehicle parrots back to the fueling station via the
wireless connection established between the fueling station RSU and
the vehicle OBU. As another example, the nozzle information may
include a fluid flow signature delivered to the fuel tank that
causes changes in tank parameters (e.g., tank pressure) transmitted
by the vehicle to the fueling station via the RSU/OBU wireless
connection. As yet another example, nozzle information may include
both a nozzle ID and a fluid flow signature so that feedback
received from the vehicle via the wireless connection comprises
both the nozzle ID and changes in transmitted tank parameters
resulting from delivering the flow signature to the vehicle's fuel
tank.
[0104] Act 1650 comprises associating the wireless connection
between the fueling station and the vehicle (e.g., a V2X connection
between the fueling station RSU and the vehicle OBU) with the
corresponding dispenser nozzle based on the received feedback to
pair the dispenser nozzle with the vehicle. Thereafter, the fueling
station knows that fueling information (e.g., tank parameters)
received over the wireless connection corresponds to the vehicle
engaged with the paired nozzle and can be used to initiate a
fueling event with that vehicle via the paired nozzle (act 1660).
For example, fueling information received via the wireless
connection over which the feedback was received may be routed via
the fueling station's communication network to the dispenser having
the paired nozzle so that the dispenser can control the fueling of
the vehicle's tank, aspects of which are described in further
detail below.
[0105] By providing nozzle information to the vehicle and receiving
feedback from the vehicle responsive to the nozzle information, the
fueling station can accomplish vehicle-to-nozzle pairing without
requiring the vehicle to provide vehicle identification or vehicle
operator identification information to the fueling station.
However, in some circumstances, the vehicle may provide (or may
have provided) identification information voluntarily in order to
perform actions such as automatic payment, nozzle reservation, etc.
Thus, vehicle-to-nozzle pairing method 1600 allows for, but does
not require, vehicle anonymity. If vehicle identification
information is provided to the fueling station, this information
may be used during vehicle-to-nozzle pairing (e.g., to confirm that
a vehicle that has made a nozzle reservation is the same vehicle
engaged with the nozzle) and/or may be used during the fueling
event (e.g., to perform automatic payment), as discussed in further
detail below.
[0106] According to some embodiments, a vehicle may engage with a
dispenser nozzle prior to establishing a wireless connection with
the fueling. In such circumstances, the act of engaging the
dispenser nozzle with the vehicle and/or the act of providing
nozzle information to the vehicle may trigger the fueling station
or the vehicle to initiate establishing a wireless connection
between, for example, a fueling station RSU and the vehicle's OBU.
As such, act 1610 need not be performed first, but instead may be
performed after the vehicle engages, or in response to the vehicle
engaging with a dispenser nozzle at the fueling station and/or
after or in response to nozzle information being provided by the
dispenser via the nozzle to the vehicle, as the aspects are not
limited in this respect.
[0107] FIG. 7 illustrates an exemplary vehicle-to-nozzle pairing
method in which providing nozzle information to a vehicle includes
electrically providing a nozzle ID to the vehicle that corresponds
to the nozzle engaged with the vehicle. In exemplary method 1700,
acts 1610 and 1620 may be the same as or similar to acts 1610 and
1620 described in connection with FIG. 6. Act 1730 comprises
providing nozzle information to the vehicle at least in part by
electrically transmitting a nozzle ID to the vehicle corresponding
to the nozzle engaged with the vehicle (e.g., by performing act
1620). Electrically transmitting a nozzle ID may be performed using
any type of electrical-based communication (e.g., electrical,
electro-optical, electromagnetic, etc.) including, but not limited
to, direct electrical communication, radio frequency communication,
optical communication and/or any suitable wired or wireless
communication technique suitable for transmitting a nozzle ID. It
should be appreciated that act 1730 may also include providing
additional nozzle information, either electrically or otherwise, to
vehicle, as the aspects are not limited to transmitting any
particular nozzle information to the vehicle.
[0108] The nozzle ID may be any type of identifier that can be used
to differentiate the nozzle from the other nozzles at the fueling
station at a given moment in time. According to some embodiments, a
nozzle ID corresponding to a given nozzle is changed each time a
nozzle is engaged with a vehicle. For example, the nozzle ID can be
changed for each nozzle by configuring the respective dispenser(s)
(e.g., a dispenser controller or other computing unit) to generate
a random or pseudo-random number and assign the generated number to
a nozzle that has been engaged with a vehicle, select from a set of
predetermined nozzle IDs, or perform any other suitable technique
of assigning a nozzle ID to each nozzle so that no two nozzles are
assigned the same nozzle ID at the same time and so that the nozzle
ID of a nozzle changes periodically, after each fueling event
and/or in response to some other event, as the aspects are not
limited in this respect. According to some embodiments, nozzle IDs
assigned to different nozzles are changed periodically (e.g.,
hourly, daily, etc.) as an alternative, or in addition to, changing
the nozzle each time a nozzle is engaged with a vehicle.
[0109] Act 1740 comprises receiving feedback from the vehicle
responsive to providing nozzle information, including receiving the
nozzle ID that was provided to the vehicle in act 1730 as feedback
via a wireless connection established between the vehicle and
fueling station (e.g., a V2X connection established in act 1610
between the fueling station RSU and the vehicle's OBU), For
example, the vehicle may parrot the nozzle ID received from the
nozzle (e.g., via a nozzle transmitter such as an RFID tag,
Bluetooth.RTM. transmitter, IrDA transmitter, etc.) back to the
fueling station via the wireless connection between the fueling
station and the vehicle. As discussed above, a wireless connection
between the fueling station may be established before or after the
nozzle is engaged with the vehicle and/or before or after the
nozzle ID is electrically transmitted to the vehicle, and may be
triggered by performing either of these acts in circumstances where
a wireless connection is not already established.
[0110] Act 1750 comprises associating the wireless connection
established between the fueling station and the vehicle with the
dispenser nozzle engaged with the vehicle based at least in part on
receiving the nozzle ID via the wireless connection. According to
some embodiments, when a nozzle ID is received via the wireless
connection, the fueling station may associate the wireless
connection with the dispenser nozzle identified by or corresponding
to the received nozzle ID so that information received from the
vehicle via the wireless connection (e.g., fueling information such
as tank parameters, fueling protocols, etc.) may be routed to the
dispenser comprising the corresponding nozzle to control a
subsequent fueling event (e.g., a fueling event initiated in act
1660 as discussed above in connection with FIG. 6).
[0111] According to some embodiments, the fueling station
distributes information received over each established wireless
connection between the fueling station and vehicles within the zone
of communication to each of the dispensers. When a nozzle ID is
received via one of the wireless connections, the fueling station
may indicate to the dispenser comprising the corresponding nozzle
which wireless connection the nozzle ID was received over so that
the dispenser knows to use information received via that wireless
connection to control a subsequent fueling event via the identified
nozzle. Accordingly, associating a wireless connection with a
nozzle engaged with a vehicle may include routing fueling
information received via the wireless connection to the
corresponding dispenser, or indicating to the corresponding
dispenser which fueling information presently being distributed to
the dispenser should be used to control a fueling event at the
corresponding nozzle.
[0112] FIG. 8 illustrates an exemplary system configured to
electronically transmit a nozzle ID to a vehicle to facilitate
vehicle-to-nozzle pairing, in accordance with some embodiments. The
system illustrated in FIG. 8 may be similar in many respects to the
system illustrated in FIG. 5. In this exemplary system, dispensers
are configured to electronically transmit a nozzle ID to a vehicle
engaged with the nozzle. For example, to electronically transmit a
nozzle ID corresponding to the respective nozzle to a vehicle,
nozzle 2225a' may comprise a nozzle ID transmitter 2227a and nozzle
2225b' may comprise a nozzle ID transmitter 2227b configured to
connect, either wirelessly or via a physical "wired" connection, to
a receiver located at the vehicle (e.g., ID receiver 1127 located
proximate the fueling receptacle 1125 of vehicle 1100a).
[0113] According to some embodiments, nozzle ID transmitters 2227a
and 2227b include a wireless transmitter for wirelessly
transmitting a nozzle ID to a wireless receiver of a vehicle
engaged with the nozzle. In embodiments configured to communicate
wirelessly, wireless nozzle ID transmitters and receivers may
communicate using any suitable communication technology including,
but not limited to, radio frequency communication, optical
communication, etc., provided the communication range is limited to
prevent unintentional communication links from being established
between a dispenser nozzle and a vehicle to which the nozzle has
not been engaged. For example, wireless nozzle ID transmitters may
comprise a low power RFID transmitter (e.g., an RFID tag)
positioned on the nozzle so that a corresponding wireless receiver
on the vehicle can receive information from the transmitter only
when the nozzle is engaged with the fueling receptacle of the
vehicle (or when the vehicle's ID receiver is in such close
proximity to ensure that only that vehicle can receive nozzle
information from the nozzle). As another example, wireless nozzle
ID transmitters may comprise an IrDA transmitter that similarly
prevents a communication link from being established unless and
until the corresponding nozzle has been engaged with the vehicle.
Thus, in the exemplary system illustrated in FIG. 7, vehicle 1100
that has engaged with nozzle 2225a' via fueling receptacle 1125 is
the only vehicle capable of receiving information 1025', which
includes the nozzle ID corresponding to nozzle 2225a'.
[0114] According to some embodiments, nozzle ID transmitters 2227a
and 2227b include a physical connection for transmitting a nozzle
ID to a receiver of a vehicle engaged with the nozzle via a "wired
connection" using any suitable electrical connection between the
nozzle ID transmitter and the receiver at the vehicle. For example,
the dispenser nozzle may be configured so that when the nozzle is
correctly engaged with the fueling receptacle so that the nozzle
can dispense fuel to the vehicle's fuel tank, the nozzle ID
transmitter also makes a physical connection with the receiver at
the vehicle to create a wired link over which information 1025'
(including the nozzle ID) may be transmitted.
[0115] According to some embodiments, each time a nozzle is engaged
with a vehicle the nozzle is assigned a different nozzle ID. For
example, dispensers 2225a' and 2225b' may change the nozzle ID
corresponding to a nozzle each time the nozzle is engaged with a
different vehicle. The nozzle ID can be changed for each nozzle by
configuring dispensers (e.g., a dispenser controller or other
computing unit) to generate a random or pseudo-random number and
assign the generated number to a nozzle that has been engaged with
a vehicle, select from a set of predetermined nozzle IDs, or any
other suitable manner of assigning a nozzle ID to each nozzle so
that no two nozzles are assigned the same ID at the same time.
According to some embodiments, nozzle IDs assigned to different
nozzles are changed periodically (e.g., hourly, daily, etc.) as an
alternative, or in addition to, changing the nozzle each time a
nozzle is engaged with a vehicle.
[0116] In response to receiving a nozzle ID, the vehicle may
transmit the nozzle ID back to the fueling station via a wireless
connection established between the fueling station and the vehicle.
For example, in the system illustrated in FIG. 8, a nozzle ID
corresponding to nozzle 2225a' is provided to the vehicle via link
1025' established between transmitter 2227a and receiver 1127 after
the nozzle was engaged with fueling receptacle 1125 of the vehicle.
In response to receiving the nozzle ID, vehicle 1100 provides
feedback to fueling station 2200 at least in part by causing OBU
1150 to transmit the received nozzle ID to fueling station RSU 2250
via wireless connection 2050. It should be appreciated that other
information may be provided over communication link 2050, including
dispenser information, dispenser and/or nozzle status, fuel station
information and/or status, etc., as the aspects are not limited to
transmitting a nozzle ID. Based on the received feedback, RSU 1250
can ascertain that communication link 2050 is the communication
link with vehicle 1100 engaged with nozzle 2225a'.
[0117] FIG. 9 illustrates an exemplary vehicle-to-nozzle pairing
method in which providing nozzle information to a vehicle includes
delivering a fluid flow signature to the vehicle via the dispenser
nozzle. Exemplary method 1900 includes establishing a connection
between the fueling station (act 1610) and engaging a dispenser
nozzle with the vehicle (act 1620) that may be performed in the
manner described above in connection with FIGS. 6 and 7. As
discussed above, establishing a connection between the fueling
station may be performed before or after engaging a dispenser
nozzle with the vehicle. Act 1930 comprises receiving fueling
information, including tank parameters of the vehicle (e.g., tank
size, measured tank pressure, measured tank temperature, etc.), via
the established connection. Act 1930 may be performed any time
after the connection is established with the fueling station,
either before the nozzle is engaged with the vehicle, after the
nozzle is engaged with the vehicle, or both (in circumstances in
which the connection is established prior to engaging the nozzle).
According to some embodiments, the fueling station monitors the
fueling information received via the connection throughout the
period in which the fueling station and vehicle remain connected
via the connection established in act 1610. For example, the
vehicle may continuously and/or regularly (e.g., in real-time or
near real-time) transmit updated tank parameters via the
established connection so that the fueling station receives
up-to-the-instant or sufficiently current updated fueling
information from the vehicle and can monitor changes thereof. That
is, act 1930 may be performed repeatedly (e.g., continuously and/or
regularly) throughout the vehicle-to-nozzle pairing process (and
throughout a fueling event, as discussed in further detail below),
and may also monitor tank parameters prior to vehicle engagement
with a nozzle (e.g., any time or throughout the period of time that
the vehicle and the fueling station have an established wireless
connection.
[0118] Act 1940 comprises delivering a fluid flow signature to the
vehicle via the dispenser nozzle. For example, the dispenser may
control the flow of hydrogen gas through the nozzle in a specific
on/off pattern so that the fuel tank of the vehicle engaged with
the nozzle experiences the delivered fluid flow signature. The
fluid flow signature may be any pattern of flow that results in one
or more detectable changes in the tank parameters (e.g., a
detectable change in measured tank pressure) in response to the
fluid flow signature being delivered to the fuel tank of the
vehicle engaged to the nozzle. According to some embodiments, the
fluid flow signature delivered via a nozzle is changed each time
the nozzle is engaged with a different vehicle and/or the fluid
flow signature delivered via the nozzle may be changed periodically
(e.g., hourly, daily, etc.). The specific fluid flow signature
delivered via a nozzle may be assigned in any manner, either
statically or dynamically, so that no two nozzles deliver the same
fluid flow signature at the same time (or during a same interval of
time), thus allowing the nozzle to be identified based on the fluid
flow signature delivered to the vehicle currently engaged with the
nozzle.
[0119] Act 1950 comprises associating the connection established in
act 1610 with the nozzle engaged with the vehicle based at least in
part on one or more tank parameters received via the connection
established in act 1610. As discussed above, act 1930 may be
repeated at any desired frequency so that the fueling station can
monitor changes in one or more tank parameters over time to match
those changes to the expected response of the fuel tank to the
fluid flow signature delivered to the vehicle in act 1640. For
example, the fueling station may monitor one or more tank
parameters received via the established connection and may
associate the connection with the nozzle that delivered a given
fluid flow signature (e.g., the specific fluid flow signature
delivered in act 1940) when changes in the one or more tank
parameters match an expected response of the fuel tank to receiving
the given fluid flow signature. That is, when changes in the one or
more tank parameters received via the established connection
reflects the expected response to the fluid flow signature, the
fueling station can ascertain which connection is associated with
the vehicle engaged at the corresponding nozzle, thus allowing or
facilitating the vehicle-to-nozzle pairing to be resolved.
[0120] For example, referring again to FIG. 5, providing nozzle
information 1025 may include dispenser 2220a controlling nozzle
2225a to deliver a gas flow pattern corresponding to the nozzle to
fueling receptacle 1125 of vehicle 1100a. The hydrogen gas flow
pattern then causes changes to the tank parameters that are
reflected in the vehicle tank data received by vehicle ECM 1160 and
transmitted to RSU 2250 via OBU 1150 over established wireless
connection 2050a. Fueling station 2200 may be configured to monitor
tank data received from each of the vehicles with which the fueling
station has established a connection. When changes in received tank
data from a vehicle matches expected changes resulting from
delivering a fluid flow pattern, the fueling station associates the
wireless connection over which the matched tank data was received
with the nozzle that delivered the corresponding flow pattern,
thereby pairing the vehicle and the nozzle.
[0121] FIG. 10 illustrates an exemplary vehicle-to-nozzle pairing
method which provides nozzle information to a vehicle both by
electrically transmitting (e.g., via wireless optical or radio
frequency transmission) a nozzle ID and by delivering a fluid flow
signature to the vehicle via the dispenser nozzle. For example,
when a vehicle engages with a nozzle (act 1620), the dispenser may
electrically transmit a nozzle ID corresponding to the nozzle to
the vehicle that uniquely identifies the nozzle (act 1730') and may
deliver a flow signature to the vehicle to cause an identifiable
change in tank parameters of the vehicle (act 1940'). As a result,
feedback transmitted from the vehicle and received by the fueling
station via a wireless connection established in act 1610 may
include both the nozzle ID (act 1740') and tank information (act
1930').
[0122] Act 10050 comprises associating the connection over which
the feedback was received with the nozzle engaged with the vehicle.
For example, act 10050 may include any of the actions described in
connection with acts 1750 and 1950 of FIGS. 7 and 9, respectively,
to resolve the correct vehicle-to-nozzle pairing. Basing
vehicle-to-nozzle pairing on both types of feedback allows the
fueling station to confirm the association and/or may enable
vehicle-to-nozzle pairing when one or the other technique is not
available. For example, some vehicles may not include the receiver
needed to receive the electrically transmitted nozzle ID, or the
receiver may currently be inoperable, but vehicle-to-nozzle pairing
could still be accomplished via flow signature techniques.
[0123] As discussed, the V2X communication techniques discussed
above allow a fueling station to establish a controller area
network (CAN) communicatively connecting vehicles in-range of the
fueling station's RSU (e.g., as described in connection with the
CAN illustrated in FIG. 2A) and/or communicatively connecting
vehicles in a larger zone of communication using vehicle hopping
(e.g., as described in connection with the CAN illustrated in FIG.
2B and vehicle hopping techniques described in connection with FIG.
3). As a result, a fueling station can receive a rich set of
information from vehicles at, near and/or at a distance from the
fueling station that can be used to perform a wide range of actions
at the fueling station, some examples of which are discussed in
further detail below. In the following discussion of exemplary
actions taken by the fueling station, the described actions may be
performed by the fueling station via any one or combination of
components at the fueling station including, but not limited, any
one or combination of components connected to the fueling station
network such as one or more fueling station controllers, dispenser
controllers, system controllers for sub-systems of the fueling
station (e.g., controllers for hydrogen cooling systems, hydrogen
gas supply systems, dispenser island systems, etc.), or any other
suitable component or combination of components.
[0124] According to some embodiments, based on information received
from vehicles in the CAN, the fueling station can predict the
near-term demand on the fueling station from the number of vehicles
needing refueling and can configure the fueling station to meet
those demands and/or to reduce energy consumption when the
information indicates the ability to do so. FIG. 4B illustrates an
exemplary method performed in response to receiving fueling
information via a CAN comprising a road-side unit at a fueling
station and a plurality of on-board units associated with
respective vehicles with which the road-side unit has established
respective wireless connections (e.g., by performing acts 1410 and
1420 as discussed above in connection with FIG. 4A). The fueling
information received by performing act 1420 may include any
information or combination of information from the vehicle that
facilitates determining an expected demand at the fueling station
including, but not limited to one or more tank parameters that
allow the fueling station (e.g., via one or more controllers
coupled to road-side unit) to determine how much fuel a vehicle
presently has, location of the vehicle to determine how far the
vehicle is from the fueling station, whether a vehicle is moving
towards or away from the fueling station, proximity of a vehicle to
another fueling station, etc.).
[0125] In the embodiment illustrated in FIG. 4B, this received
fueling information is used by the fueling station (e.g., via the
one or more controllers) to estimate the expected refueling demand
at the fueling station so that the fueling station can prepare the
fueling station to meet the expected demand (act 1432). In act
1434, the expected demand determined from the received fueling is
used to power up one or more components of the fueling station
(e.g., to meet an expected increase in demand) or power down one or
more components of the fueling station in view of an expected
decrease in demand. For example, if the fueling information
obtained from the CAN indicates that the fueling station is likely
to experience of period of little or no demand, the fueling station
may respond by powering down one or more components of the fueling
station. As another example, the fueling station may be in a
reduced power consumption state (e.g., one or more components of
the fueling station may have been powered down to reduce power
consumption) and in response to information received via the CAN
indicating relatively near-term demand, the fueling station may
power up one or more components of the fueling station to ensure
that the fueling station is able to meet the demand.
[0126] According to some embodiments, the fueling station may
respond to information received via the CAN to disable operation of
one or more refrigeration units (e.g., power down one or more
refrigeration units or one or more components of a refrigeration
unit), associated pumps, etc. of a hydrogen cooling system to
reduce power consumption at the fueling station when information
received via the CAN indicates a level of demand that allows the
fueling station to operate in a reduced power state. For example,
disabling operation of a refrigeration unit may comprise powering
down or turning off one or more components of the refrigeration
unit to save on power that would otherwise be consumed to reduce
and/or maintain the temperature of coolant used by a hydrogen
cooling system to chill hydrogen gas. Disabling operation of a
component (e.g., a refrigeration unit, dispenser, pump, motor,
etc.) may involve powering down or turning off some portions of the
component while keeping some portions of the component powered
up.
[0127] According to some embodiments, the fueling station responds
to information received via the CAN to enable operation of one or
more refrigeration units (e.g., power up one or more refrigeration
units or one or more components of a refrigeration unit),
associated pumps, etc. of a hydrogen cooling system when
information received via the CAN indicates the need to do so to
meet the likely near-term refueling demands on the fueling station.
For example, enabling operation of a refrigeration unit may
comprise powering up or turning on one or more components of the
refrigeration unit that were previously disabled to resume reducing
and/or maintaining the temperature of coolant used by a hydrogen
cooling system to chill hydrogen gas. Enabling operation of a
component (e.g., a refrigeration unit, dispenser, pump, motor,
etc.) refers generally to powering up or turning on portions of the
component needed to operate and/or resume operation. Further
examples of using information received via the CAN to reduce power
consumption, optimize performance and/or otherwise configure
components of the fueling station are discussed in further detail
in connection with the exemplary hydrogen cooling systems described
below.
[0128] According to some embodiments, the fueling station may
respond to information received from the CAN to provide information
to vehicles with which the fueling station has established a
connection such as status information on the fueling station or
status information of another fueling station, fuel availability,
estimated wait times, the availability of fuel at different
temperature classes, estimated wait times, navigation information
to the fueling station or other fueling stations, etc. (e.g., when
performing act 1420 in the exemplary methods illustrated in FIGS.
4A-C). In this manner, status information may be broadcast to all
vehicles to which a fueling station is connected and/or information
specific to a given vehicles may be transmitted over the respective
wireless connection so that different information is transmitted to
different vehicles based on the specific information provided by
the corresponding vehicle over its established connection.
[0129] Any combination of the above information may be transmitted
from the fueling station RSU to OBUs of vehicles having established
connections with the RSU, and the vehicles' ECM can display this
information to the vehicle operator and/or recommend that the
operator of the vehicle drive to the fueling station when the
conditions at the fueling station are favorable and/or suitable or
recommend that the operator of the vehicle continue to a different
fueling station where conditions may be more favorable and/or
suitable. In embodiments in which navigation information to one or
more fueling stations is provided, this navigation information can
be used to guide the operator of the vehicle to the fueling station
that can best meet the current needs of the vehicle. In this way,
helpful fueling information may be provided to vehicles to assist
in refueling vehicles and/or current fueling demands of vehicles in
a zone of communication can be distributed across multiple fueling
stations to optimally meet that demand.
[0130] According to some embodiments, the fueling station may
respond to information received from the CAN to perform nozzle
reservation for a vehicle so that the vehicle can be assured of
having an available nozzle at which to refuel when the vehicle
arrives at a fueling station (e.g., at a specified reservation
time, within a specified reservation window, any time after a
specified earliest reservation time, etc.). FIG. 4C illustrates an
exemplary method performed in response to receiving a nozzle
reservation request via a CAN comprising an RSU at a fueling
station and one or more OBUs associated with a respective
vehicle(s) with which the road-side unit has established a wireless
connection (e.g., by performing acts 1410 and 1420 as discussed
above in connection with FIG. 4A), in accordance with some
embodiments.
[0131] In the exemplary nozzle reservation method illustrated in
FIG. 4C, for example, the RSU at a fueling station receives a
request via the OBU of a vehicle to reserve a nozzle for a
refueling event (act 1424) during data exchange with the OBU (act
1420). The request may include the amount of fuel needed, the
required or preferred temperature class of the fill, a time or time
periods for the reservation, or the fueling station may determine
the parameters of the request from other information received from
the vehicle (e.g., tank volume and current tank pressure, tank
temperature, location of the vehicle if provided, etc.). In act
1426, the fueling station (e.g., via one or more controllers
coupled to the RSU) negotiates the reservation with the
vehicle.
[0132] Negotiating the reservation may include any processing
needed to confirm a nozzle reservation for the requested
reservation and may include both data exchange (e.g., act 1426 as
part of data exchange 1420) and performing action at the fueling
station (e.g., act 1426 as part of act 1430). For example,
negotiating the reservation may include one or any combination of
determining whether there is one or more dispensers at the fueling
station that are capable of fulfilling the reservation or can be
made ready to fulfill the reservation, further data exchange with
the OBU to obtain additional information, modifying one or more
parameters of the requested reservation, proposing one or more
parameters for the requested reservation, providing a reservation
identifier, confirming the reservation, etc. Once the nozzle
reservation has been negotiated, one or more actions may be
performed at the fueling station to prepare for fulfilling of the
reservation (act 1436) including, but not limited to, associating
information with the reservation, informing one or more dispensers
of the reservation, powering up one or more components of the
fueling station to make sure that the requested fueling event can
be performed when the vehicle arrives for its reservation, etc.,
examples of which are described in further detail below. When the
vehicle with the reservation arrives at the fueling station, the
fueling station fulfills the reservation (act 1438) by performing a
fueling event via a reserved dispenser.
[0133] A fueling station may prepare for a reservation (e.g., may
perform act 1436) in any number of suitable ways. For example, if
multiple dispenser nozzles are ready and available (or can be made
to be ready and available prior to the reservation time) to perform
the reserved fueling event, each available dispenser may be
informed of the reservation. In this way, any of the available
dispensers may still be used to perform intervening fueling events
so long as at least one dispenser remains ready to fulfill the
reservation. As such, vehicles that may arrive at the fueling
station prior to the reservation need not be inconvenienced by
inadvertently pulling up to a specific dispenser that has been
temporarily dedicated to fulfilling a reservation and instead can
utilize the dispenser unless and until only one dispenser nozzle
remains that can fulfill the reservation. The dispenser numbers,
for example, of dispensers that can fulfill the reservation may be
conveyed to the vehicle with the reservation so that the vehicle
can refuel at any of those dispensers. Dispenser availability can
be updated (e.g., by performing further data exchange 1420) as
needed prior to the reservation in the event that intervening
vehicles utilizing one or more dispensers to refuel cause that
dispenser to be unavailable to fulfill the reservation. According
to some embodiments, a single dispenser (or a single nozzle of a
multi-nozzle dispenser) is assigned to fulfill a reservation and
therefore may be unavailable to other vehicles during some
prescribed time unless the dispenser is capable of performing one
or more refueling events and still be able to fulfill the
reservation.
[0134] According to some embodiments, the reservation request
received by the fueling station via the established connection
(e.g., act 1424) may include identification information associated
with the vehicle or the vehicle's operator and this identification
information may then be associated with the reservation (e.g.,
during act 1426 or 1436). That same identification information may
then be conveyed to the fueling station during vehicle-to-nozzle
pairing using any of the techniques described in the foregoing to
confirm that the vehicle engaged at a nozzle has reserved the
nozzle (e.g., when a single nozzle is assigned to fulfill the
reservation) and/or to indicate that the subsequent refueling event
fulfills that reservation (e.g., when any available dispenser can
be used to fulfill the reservation).
[0135] According to some embodiments, nozzle reservation may be
performed anonymously. For example, when a vehicle requests a
nozzle reservation and the fueling station confirms the reservation
(e.g., by performing acts 1424 and 1426), the fueling station may
associate the established connection with the vehicle to that
reservation (e.g., by assigning a unique reservation number to the
established connection). Thus, when the fueling station associates
that established connection with a given nozzle during
vehicle-to-nozzle pairing using any of the techniques describe
above, the fueling station can confirm that this connection also
has the reservation associated with it. Anonymous nozzle
reservation can therefore be performed both when a single dispenser
is dedicated to the reservation or when any available dispenser can
be used to fulfill the reservation. According to some embodiments
using the above technique for anonymous nozzle reservation, the
same connection with the fueling station over which the reservation
request was made may need to be maintained through to the
completion of the refueling event. However, according to some
embodiments, when a reservation is made, the fueling station may
assign a unique number to that reservation (e.g., a pseudo-random
number of sufficient length that ensures the reservation cannot be
spoofed) and convey that reservation number to the vehicle (e.g.,
during reservation negotiation 1426). Should the established
connection be disconnected (either inadvertently or intentionally
in act 1440), the vehicle may convey the unique reservation number
to the fueling station when a connection between the vehicle and
the fueling station is established prior to a fueling event (e.g.,
during act 1610 of refueling event 1600 illustrated in FIG. 6) so
that the connection established for the refueling event need not be
the same connection over which the reservation was made.
[0136] According to some embodiments, a V2X connection with a
vehicle and a fueling station is used to exchange payment
information to allow automatic payment for a fueling event. For
example, the vehicle may provide debit or credit card information
or other information needed to perform any type of electronic
payment to the fueling station over the established connection
(e.g., via data exchange 1420) to facilitate secure transmission of
payment information that allows the fueling system to process
payment for a fueling event without needing the vehicle operator to
interact with the dispenser (e.g., by inserting a debit or credit
card into the dispenser) and/or fueling station personnel to pay
for the fueling event, facilitating simpler and more convenient
transactions and/or more efficient fueling events.
[0137] According to some embodiments, a fueling station uses
information received from vehicles via the CAN to optimize a
fueling event for individual vehicles. As discussed above, the
increased bandwidth of V2X communications allows for a richer set
of information about a vehicle to be transmitted to the fueling
station (e.g., via data exchange 1420). For example, in addition to
the limited set of tank parameters (e.g., tank pressure, tank
temperature, tank size, etc.) transmitted via conventional LOS
communications established between the vehicle and the dispenser
via the nozzle, information about the specific fueling preferences,
requirements and/or capabilities may be transmitted to the fueling
station so that the dispenser can optimize a fill according to the
preferences, requirements and/or capabilities of a specific vehicle
conveyed to the fueling station via an established V2X connection.
As a result, a dispenser may be configured to deliver a faster fill
when information received from the vehicle confirms that the
dispenser can do so safely.
[0138] According to some embodiments, a fueling protocol for the
vehicle may be transmitted to the fueling station via the
established V2X communication that can be used by the dispenser to
optimize a fueling event for the vehicle. The fueling protocol may
include, among other information, target tank pressure as a
function of time that the dispenser should follow when performing a
fueling event. This pressure profile can be used by the dispenser
controller to vary the flow rate of hydrogen delivered to the fuel
tank of a vehicle to follow the pressure profile specified by the
fueling protocol. In this way, a dispenser can be configured to
refuel a vehicle in accordance with the fueling protocol specified
by the vehicle, further details of which are discussed in
connection with the exemplary dispenser controllers described
below.
[0139] According to some embodiments, information received by a
fueling station via a CAN (e.g., via data exchange 1420) may be
used to develop trend data on demand (e.g., time of day of peak
demand, average demand for the fueling station, weekday vs. weekend
demand, predominant type of vehicle being refueled during different
times, etc.) that can be used to optimize the fueling station. For
example, trend data can be used to create daily demand schedules
that can be used by the fueling station to guide in the powering up
or powering down one or more components of the fueling station.
This information may be used to supplement and/or confirm current
demand information received via the CAN. For example, the fueling
station may determine from information received via the CAN that
there may be little or no near-term demand but may decide to keep
one or more components powered-up based the proximity in time to
peak demand time captured by the trend data. Trend data may be used
in multiple other ways such as determining an optimal configuration
of components (e.g., hydrogen cooling system configuration),
scheduling delivery of hydrogen gas, to guide in optimally
configuring a new fueling station deployment or in other ways, as
the aspects are not limited in this respect.
[0140] As discussed above, many current fueling protocols adopted
by hydrogen refueling stations require hydrogen fuel to be cooled
between -40.degree. C. to -17.5.degree. C. prior to dispensing to
the vehicle to ensure the vehicle's fuel tank maintains bulk gas
temperatures below 85.degree. C. regardless of ambient temperatures
or previous driving conditions. As discussed above, existing
hydrogen gas fueling stations typically employ either a large
chilled aluminum block that provides a thermal reservoir to cool
hydrogen gas prior to dispensing or a diffusion-bonded heat
exchanger that cools hydrogen gas by circulating chilled coolant
through a plate-to-plate configuration. The inventors have
recognized that while each technique has some advantages, both have
significant drawbacks. Aluminum block heat exchanger systems are
massive (e.g., 600-1000 kg) and costly (e.g., $100-150K per
installation), and typically require breaking ground to bury the
aluminum block beneath the dispenser, which may limit the locations
for these installations and increases the cost. Additionally,
contact resistance between the aluminum block and the
stainless-steel tubing causes heat transfer inefficiency resulting
in a low UA (overall heat transfer coefficient, U, multiplied by
the heat transfer area, A) heat exchanger. Thus, aluminum block
heat exchangers have relatively long fueling times (e.g., 5
minutes). Aluminum block heat exchangers generally are employed on
a per dispenser basis so that multiple installations are required
for fueling stations having multiple dispensers, making the
aluminum block heat exchanger solution difficult and costly to
scale. One advantage of aluminum block heat exchangers is that once
cooled, the large thermal mass of the aluminum block allows the low
temperature of the aluminum block to be maintained with relatively
low energy output (e.g., 19 kW) so that relatively small capacity
refrigeration units can be used maintain the target temperature of
the aluminum block.
[0141] Conventional high UA heat exchanger systems (e.g., cooling
systems that employ diffusion-bonded plate-to-plate heat
exchangers) are typically even costlier (e.g., $200K per
installation), but these systems provide for a high UA heat
exchange allowing for faster fill times (e.g., on the order 2
minutes for some installations). Conventional diffusion-bonded heat
exchanger systems employ relatively low volume coolant reservoirs
(e.g., between 20-50 gallons) and large-capacity refrigeration unit
(e.g., 35-70 kW capacity chillers) are required to maintain the low
temperature of this low thermal mass coolant reservoir to meet peak
fueling demands. Use of large-capacity chillers has a number of
drawbacks. In particular, large-capacity chillers are themselves
expensive and consume significant power and to the cost of
operating these refrigeration units. Also, the large size of these
chillers often prevents installation of the chiller proximate the
dispenser. As a result, the coolant reservoir and chiller are
typically installed some distance from the dispenser and must be
connected to the heat exchanger at the dispenser with lengths of
tubing.
[0142] The inventors have designed and developed high UA hydrogen
cooling systems that address one or more of the above drawbacks
associated with conventional hydrogen cooling systems. For example,
the inventors have appreciated that the conventional approach of
using a small-volume coolant reservoir and large-capacity
refrigeration unit (chiller) results in both large and costly
hydrogen cooling systems. The inventors recognized that by
increasing the volume of the coolant reservoir, the thermal energy
capacity of the reservoir can be increased, thus taking advantage
of the high thermal mass characteristics of aluminum block heat
exchangers without incurring the heat transfer inefficiency and
other drawbacks of that solution. According to some embodiments, a
heat exchanger system comprises a coolant reservoir of between
50-700 gallons (e.g., a 100-gallon tank of a coolant such as
glycol) to increase the thermal energy storage capacity of the
reservoir. As used herein, a large-volume reservoir refers to
reservoir with an equal to or greater than 50 gallon holding
capacity (in some embodiments, preferably greater than 80 gallons,
and in some embodiments, preferably 100 gallons or larger).
[0143] The inventors further recognized that the increased thermal
storage capacity of the large volume reservoir allows for the use
of a significantly smaller refrigeration unit. Specifically,
because increasing the volume of the reservoir increases the
thermal energy capacity, the volume of the reservoir can be sized
to handle peak demand so that the refrigeration unit need only be
sized to handle the base load refueling needs of the fueling
station. According to some embodiments, a small-capacity
refrigeration unit is used to cool a large volume coolant
reservoir, both sized according to the needs of the fueling system.
As used herein, a small-capacity refrigeration unit (chiller)
refers to a refrigeration unit have a capacity of greater than 3 kW
and less than or equal to approximately 21 kW. The capacity of a
refrigeration unit is often stated in terms of tons where each ton
provides an additional 3.517 kW capacity approximately. Thus, a
small-capacity refrigeration unit refers to between, and including,
between approximately 1-ton and 6-ton refrigeration units.
[0144] Furthermore, the inventors have appreciated that aspects of
this design for hydrogen cooling (e.g., large volume reservoirs and
small chillers relative to conventional approaches) provides a
flexible design approach that can be optimized according to the
performance needs of a particular fueling station. For example, a
fueling station requiring higher performance may size-up the
capacity of the refrigeration unit to reduce recovery times and/or
increase the volume of the coolant reservoir to increase the peak
capacity of the station (e.g., the number of back-to-back fills
that can be performed). Fueling stations requiring less demanding
recovery times and/or that need less peak capacity capabilities can
be sized down accordingly to provide a lower cost solution that
meets the performance requirements of the fueling station, as
discussed in further detail below.
[0145] The inventors have further appreciated that aspects of the
above-described combination of components facilitate compact
designs that allow for compact hydrogen cooling system that can be
installed proximate the dispenser (e.g., next to or adjacent to one
or more dispensers) delivering chilled hydrogen into fuel tanks of
HFCVs. Additionally, using a large-volume reservoir/small-capacity
refrigeration/high UA heat exchanger combination provides a
flexible arrangement that can configured in different ways and
optimized for a particular fueling station, providing a highly
flexible, scalable and cost-effective solution to hydrogen
cooling.
[0146] According to some embodiments, the hydrogen cooling system
according to these techniques is provided in which a large-volume
coolant reservoir, small-capacity refrigeration unit and heat
exchanger are integrated and deployed as a single compact unit
(e.g., integrated within the same housing). According to some
embodiments, this integrated hydrogen cooling unit is located
proximate the dispenser(s) (e.g., adjacent to one or more
dispensers, or located on the canopy over the dispensers) for which
the unit provides cooling. According to some embodiments, a single
hydrogen cooling system provides cooling for a plurality of
dispensers. For example, a fueling station may comprise one or more
islands, each island having multiple dispensers (e.g., multiple
nozzles by which a respective multiple number of vehicles can be
simultaneously refueled). The multiple dispensers on each island
may share a single hydrogen cooling system, which cooling system
may be an integrated unit or may be of a different design, as the
aspects are not limited in this respect. According to some
embodiments, a single small-capacity refrigeration unit may be
coupled to a single large-volume reservoir or multiple large-volume
reservoirs. Using either configuration, each large-volume reservoir
may provide coolant for one or multiple exchangers that are in turn
coupled to one or multiple dispensers. A number of exemplary
configurations are illustrated and described in further detail
below.
[0147] The inventors have further appreciated that the thermal
energy capacity of a hydrogen cooling system may be increased by
using phase change material (PCM) that stores latent heat energy
during transition from one state to another (e.g., energy is stored
by the phase change material during a change from a liquid to a
solid as a result of cooling the phase change material) to increase
the heat energy capacity of the reservoir. The latent heat energy
stored by the PCM is released as the PCM changes state when
absorbing heat from a hydrogen gas to cool the hydrogen for
dispensing to the fuel tank of a vehicle. That is, heat removed
from hydrogen gas (or heat removed from conventional coolant that
has absorbed heat from hydrogen gas) results in state change of the
PCM rather than heating of the PCM (or conventional coolant) and
thus provides a thermal buffer for the hydrogen cooling system. As
a result, the increased heat energy capacity resulting from PCM
techniques can be used to increase the back-to-back fill capacity
of the hydrogen cooling system and/or to decrease the size and
expense of the refrigeration unit needed to meet the fueling
requirements of a specific refueling station. The inventors have
recognized that a class of PCMs known as eutectics characterized by
having a low temperature phase change are well suited for hydrogen
gas cooling applications, however, other PCMs may be used in some
embodiments, as discussed in further detail below.
[0148] It will be understood that all materials change state at
some temperature and are therefore strictly speaking phase change
materials. However, as used herein, a phase change material refers
to a coolant that has a phase change temperature in the range of
intended temperatures of the hydrogen cooling system and that
exists in a first state at ambient temperatures and is caused to
transition to a second state when chilled by components of a
hydrogen cooling system to store heat energy via the state
transition. Similarly, a non-PCM coolant (e.g., glycol) is a
material that has a phase change temperature outside the range of
intended temperatures of the hydrogen cooling system and that
exists in a first state at ambient temperatures and remains in that
first state when chilled by components of the hydrogen cooling
system.
[0149] According to some embodiments, the above-described hydrogen
cooling systems can employ conventional plate-to-plate diffusion
bonded heat exchangers. However, diffusion-bonded heat exchangers
are by themselves expensive, costing anywhere from $40-100K, thus
potentially limiting the scalability and/or flexibility of these
solutions. To facilitate further reduction in the cost of a
hydrogen cooling system, the inventors have developed a high UA
annular heat exchanger designed for high pressure heat exchange
that, according to some embodiments, can be used in place of
expensive diffusion-bonded heat exchangers, thereby further
lowering the cost of the hydrogen cooling system and improving the
scalability and flexibility of the solution, facilitating further
optimization capabilities in the design, configuration and
deployment of the hydrogen cooling system. As used herein, an
annular heat exchanger refers to a heat exchanger in which the
tubing through which hydrogen gas is formed into an annular coil,
examples of which are described in further detail below.
[0150] According to some embodiments, the tubing of the coil of an
annular heat exchanger is made from a material (e.g., a nickel
alloy) that is compatible with hydrogen and that can withstand the
pressure conditions of a hydrogen fueling environment and is
designed to have a thin wall thickness to increase heat transfer
efficiency of the coil. According to some embodiments, the annular
coil is finned (e.g., copper fins) to increase the surface area of
the coil to increase heat transfer efficiency. According to some
embodiments, the annular heat exchanger is of a shell-and-tube
configuration comprising an outer shell (e.g., a cylindrical shell)
through which coolant is pumped and the coil of tubing is
positioned within the outer shell so that hydrogen gas flowing
through the coil transfers heat to the coolant flowing through the
outer shell. According to some embodiments, an annular heat
exchanger comprises a plurality of coils to increase the heat
transfer capacity of the heat exchanger.
[0151] Following below are further detailed descriptions of various
concepts related to, and embodiments of, hydrogen cooling systems
for refueling of hydrogen fuel cell vehicles. It should be
appreciated that the embodiments described herein may be
implemented in any of numerous ways. Examples of specific
implementations are provided below for illustrative purposes only.
It should be appreciated that the embodiments and the
features/capabilities provided may be used individually, all
together, or in any combination of two or more features/capability,
as aspects of the systems and techniques described herein are not
limited in this respect.
[0152] FIG. 11 illustrates a block diagram of a hydrogen cooling
system, in accordance with some embodiments. The block diagram in
FIG. 11 is not drawn to scale and is meant to illustrate how
components of an exemplary hydrogen cooling system 110 are coupled
to each other and to components of a fueling station in some
embodiments. Hydrogen cooling system comprises refrigeration unit
112 coupled to reservoir 114 of coolant and configured to bring the
coolant down to low temperatures (e.g., in a range from -40.degree.
C. to -17.5.degree. C.) to facilitate fast and safe fueling of
HFCVs. As discussed above, such refrigeration units are also
referred to as chillers or coolers and, unless otherwise specified,
refrigeration unit, condenser unit, chiller and cooler will be used
interchangeably to refer to this component configured to chill
coolant that is in turn used by heat exchanger 116 to chill
hydrogen gas for dispensing into the fuel tank of an HFCV. It
should be appreciated that refrigeration unit may be any type of
cooling source ranging from using HFC's, CO.sub.2, glycol chiller
systems or cryogenic gas, cascaded refrigeration units, etc.
[0153] Heat exchanger 116 may be any component with sufficiently
high heat transfer efficiency to meet the performance requirements
of a fueling station. According to some embodiments, an annular
heat exchanger designed for high heat transfer efficiency and to
operate under the high-pressure conditions of hydrogen gas
refueling is used to implement heat exchanger 116, examples of
which are described in further detail below. According to some
embodiments, a conventional plate-to-plate heat exchanger, for
example, a diffusion-bonded heat exchanger designed for the high
pressures of hydrogen gas refueling may be used to implement heat
exchanger 116. Use of an annular heat exchanger may be preferable
for many fueling stations due to its lower cost, size and/or
flexibility (e.g., the suitability of an annular heat exchanger to
be used in conjunction with embodiments employing PCMs), but
aspects are not limited in this respect.
[0154] During a refueling event, chilled coolant from reservoir 114
and hydrogen gas from hydrogen source 122 are pumped through heat
exchanger 116 (e.g., via pumps 115) where the chilled coolant
absorbs heat from the hydrogen gas as the coolant and hydrogen gas
pass through the heat exchanger. Hydrogen source 122 refers to any
source from which heat exchanger receives hydrogen. For example,
hydrogen source 1122 may be a bank of hydrogen storage tanks at the
fueling station. According to some embodiments, hydrogen source 122
may be the dispenser in configurations where the hydrogen cooling
system is coupled downstream of the dispenser flow control valve,
examples of which are described in further detail below. The
chilled hydrogen gas may then be provided to dispenser(s) 120 for
delivery during to the fuel tank of an HFCV during a fueling event.
The coolant is recirculated back to the reservoir. Refrigeration
unit 112 is operated to maintain the desired temperature of the
reservoir and/or to recover the temperature of the reservoir
coolant to the desired temperature as one or more refueling events
increases the temperature of the reservoir coolant. For example,
coolant many be circulated between refrigeration unit 112 and
reservoir 114 to maintain or recover the desired temperature, a
refrigeration coil may be positioned within the reservoir to
maintain/recover the temperature, etc. Any of the techniques
described below in connection with FIG. 12 may be used to maintain
and/or recover a target temperature of coolant in coolant reservoir
114.
[0155] FIG. 17 illustrates a hydrogen cooling system comprising a
chiller system having a refrigeration unit and a coolant reservoir
integrated in the same housing, in accordance with some
embodiments. In the embodiment illustrated in FIG. 17, hydrogen
cooling system 1700 comprises chiller system 1712 having a
refrigeration unit 1711 and a coolant reservoir 1714 integrated in
the same housing 1709. Refrigeration unit 1711 may include an
evaporator and a condenser having one or more cascaded stages
coupled to chill coolant held in the reservoir tank. It should be
appreciated that refrigeration unit 1711 is exemplary and any
suitable refrigeration unit capable of chilling coolant to target
temperatures may be used, as the aspects are not limited in this
respect. Chiller system 1712 may be coupled to one or more heat
exchangers 1716 to provide chilled coolant via supply line(s) that
can be circulated through the heat exchanger(s) to absorb heat from
hydrogen gas from hydrogen gas source 1705 flowing through the heat
exchanger(s) 1716 to provide chilled hydrogen gas to one or more
dispensers 1720 of a fueling station. Coolant that has absorbed
heat from hydrogen gas flowing through the heat exchanger(s) may
then be returned to coolant reservoir 1714 and refrigeration unit
1711 can be operated to recover the temperature of the coolant
reservoir, for example, using any of the techniques described below
in connection with FIG. 12 for maintaining and/or recovering a
target temperature of coolant in coolant reservoir 1714. According
to some embodiments, one or more heat exchangers 1716 may also be
integrated in housing 1709 to provide a single compact hydrogen
cooling unit that can be, for example, installed on a dispenser
island to provide hydrogen cooling for one or more dispensers on
the island (e.g., between a pair of dispensers deployed at the
dispenser island that share the hydrogen cooling system), some
examples of which are described in further detail below. According
to some embodiments, the hydrogen cooling system is coupled
downstream of the flow control valve of the sensor so that hydrogen
gas from hydrogen gas source 1705 is provided to dispenser 1720 and
after flowing through the dispenser flow control valve is provided
to heat exchanger 1716 and cooled hydrogen is provided to the
dispenser nozzle for dispensing. This hydrogen gas flow path is
illustrated by dotted lines.
[0156] As discussed above, conventional high UA hydrogen cooling
systems are implemented using small-volume reservoirs (e.g., less
than 50 gallons) and large-capacity refrigeration units (e.g.,
greater than 35 kW capacity chillers), resulting in large,
expensive, high power solutions. The inventors have recognized
advantages in deploying large-volume reservoirs and small-capacity
refrigeration units to facilitate more compact, less expensive
and/or lower power hydrogen cooling systems to provide highly
flexible and scalable hydrogen cooling solutions suitable for a
wide range of fueling stations and HFCV refueling (e.g., light,
medium and heavy duty). A large-volume reservoir acts a thermal
buffer and facilitates the use of smaller refrigeration units. The
combination of a large-volume reservoir and small-capacity
refrigeration unit allows for sizing of the cooling system to meet
the performance needs of a particular fueling station. Hydrogen
cooling systems comprising large-volume reservoirs (i.e., greater
than 50 gallons, such as between 80-120 gallons for many systems,
or even larger volume reservoirs such as between 500 and 700
gallons for some medium and heavy duty applications) and
small-capacity refrigeration units (i.e., less than or equal to 21
kW, many configurations of which may employ 10 kW capacity
refrigeration units or less) can be optimized for a range of
fueling station needs, including industrial (e.g., fork lifts,
off-road vehicles, etc.), light duty (e.g., passenger vehicles,
etc.), medium-duty and heavy-duty (busses, cargo vans, semi-trucks,
etc.) applications with fueling pressures of 0 to 87.5 MPa and fuel
delivery temperatures ranging from -20-40.degree. C., examples of
which are discussed in further detail below.
[0157] FIG. 12 illustrates an exemplary process for maintaining
and/or recovering a target temperature of coolant in a hydrogen
cooling system configured for hydrogen gas refueling, in accordance
with some embodiments. As discussed above, a large-volume reservoir
may be used to store coolant that is chilled to low temperatures to
store thermal energy for use in cooling hydrogen gas for dispensing
into HFCVs. The temperature of the bulk coolant in the reservoir is
maintained and recovered using a small-capacity refrigeration unit
that may be operated according to the exemplary process 200. In act
210, the hydrogen cooling system checks to see whether the
temperature of the coolant is less than or equal to a target
temperature at which the reservoir is to be maintained. Because the
reservoir will lose some amount of heat even in the absence of a
fill event, the hydrogen cooling system may be configured to check
the temperature and operate the refrigeration unit (act 215) in the
event that the coolant temperature has increased above some
threshold temperature above the target temperature. The threshold
temperature may be chosen appropriately to avoid excessive cycles
of running the refrigeration unit throughout the day. Additionally,
the threshold temperature may be a variable threshold that changes
depending on information from the fueling station such as time of
day, current demand, predicted demand, etc. This information may be
provided by the fueling station, for example, based on information
received via the vehicle communication techniques described in the
foregoing.
[0158] Operating the refrigeration unit may include one or more
tasks such as turning the refrigeration unit on, turning on pumps
that circulate coolant through the refrigeration unit, circulating
coolant through refrigeration coils, or other acts needed to engage
the process of cooling the bulk coolant that may depend on the type
of refrigeration unit and the type of coolant (e.g., direct
refrigeration, circulation of a coolant, use of refrigeration
coils, use of cryogenic gas, etc.). Operation of the chiller may
continue until the bulk coolant temperature in the reservoir is
sufficiently lowered (e.g., until the temperature reaches a desired
target temperature). According to some embodiments, acts 210 and
215 are performed periodically in accordance with a cooling
schedule based on one or more factors, based on information from
the fueling station (e.g., received via vehicle communication
techniques), etc.
[0159] In addition to maintenance, the chiller may also be used to
recover the temperature of the bulk coolant in the reservoir after
a fill event. In particular, detection of the initiation of a
fueling event (e.g., when a dispenser nozzle is removed from its
holder and/or engaged with a vehicle) in act 220 may result in
operating the chiller (e.g., act 215 as discussed above) and
operating the heat exchanger (act 230) to cool down the hydrogen
gas before dispensing into the fuel tank of the vehicle. Operating
the heat exchanger may include turning on pumps or other components
needed to circulate coolant and pass hydrogen gas through the heat
exchanger so that the coolant can absorb heat from the hydrogen
gas. In act 240, chilled hydrogen gas is dispensed into the vehicle
according a fueling protocol determined by communication between
the dispenser and the vehicle using any of the techniques described
herein. In exemplary process 200, both the refrigeration unit and
the heat exchanger are operated. However, in some embodiments, the
refrigeration may not be operated during or throughout a fueling
event and may instead be operated after the refueling event or
according to a predetermined schedule based on, for example,
historic data regarding peak and low demand hours, the number of
vehicles in the area that may need refueling, whether the
refrigeration unit is being used to chill a different reservoir of
coolant, energy costs at different times of the day and/or based on
any other relevant information available to the refueling
station.
[0160] After the refueling event is completed, operation of the
heat exchanger may stop (e.g., pumps and/or other components may be
turned off or powered down) but the refrigeration may remain
operational to recover the target temperature of the bulk coolant
in the reservoir (e.g., acts 210 and 215 may performed until the
target temperature of the bulk coolant is recovered). As discussed
above, according to some embodiments, the refrigeration may not be
operated during the fueling event, but instead may be operated
after the refueling event (or switched over from a different
reservoir) and/or according to a cooling schedule that takes into
consideration one or more factors discussed above to optimize
operation of the fueling station.
[0161] It should be appreciated that the performance
characteristics of process 200 (or any of the alternatives
discussed above) will depend on the volume of the reservoir (e.g.,
the amount of heat energy the reservoir can store) and the capacity
of the refrigeration unit. As discussed above, the capacity of a
refrigeration unit refers to the cooling capacity (heat rejection)
of the chiller and is typically measured in kilowatts, but is also
frequently indicated by tonnage. Typical refrigeration units will
have approximately 3.517 kW of cooling capacity (heat rejection)
per ton (e.g., a 2-ton chiller would have a cooling capacity of
approximately 7 kW, a 3-ton chiller would have a cooling capacity
of 10.6 kW, a 5-ton chiller would have a cooling capacity of
approximately 17.6 kW, etc.).
[0162] FIG. 13 is a plot of recovery times as a function of
refrigeration unit (chiller) capacity at three different ambient
temperatures using a 100-gallon tank as the coolant reservoir,
which is this example holds a glycol coolant. As illustrated, by
increasing the capacity of the chiller, recovery times can be
reduced. The flexibility of this approach facilitates a
cost-benefit analysis allowing higher performance fueling stations
to be deployed at higher costs as well as lower cost installments
where higher performance may not be needed. As discussed in
connection with process 200 illustrated in FIG. 2, the chiller may
be operated during a refueling event. In such embodiments, the bulk
temperature of the reservoir undergoes recovery during the
refueling event itself. For example, a 3-ton chiller for chilling
hydrogen at 25.degree. C. ambient temperature has a recovery time
of just over 5 minutes. If, for example, the chiller is operated
during a refueling event that takes 3 minutes to complete, the
temperature of the bulk coolant may require only an additional 2
minutes of recovery time. It should be further appreciated that the
bulk coolant temperature in the reservoir need not be fully
recovered to the lowest target temperature before performing a
subsequent refueling event. For example, for a 7 kW refrigeration
unit, a first refueling event may deliver hydrogen gas at
-40.degree. C., a second back-to-back refueling event may deliver
hydrogen gas at -30.degree. C., and a third back-to-back refueling
event may deliver hydrogen gas at -20.degree. C., etc. As a result,
multiple back-to-back fills can be performed before a dispenser
will need to be temporarily taken offline to allow the temperature
of the coolant to recover. The number of back-to-back fills that
can be performed will depend on the volume of the reservoir, the
capacity of the chiller (both of which can be sized to meet the
demands of a particular fueling station) and the temperature class
requirements of the fueling station.
[0163] As discussed above, using a large-volume reservoir as a
thermal buffer allows the use of a small-capacity refrigeration
unit that can be sized for average as opposed to peak load,
facilitating a highly scalable cooling system that can be
configured to meet the demands of fueling stations with different
performance requirements. This scalability allows cooling systems
that can service light, medium and heavy-duty fueling requirements
at a lower cost. The large-volume reservoir and small-capacity
refrigeration unit also facilitates a wide variety of configuration
options such a single coolant reservoir for multiple heat
exchanger/nozzle pairs, shared heat exchangers for multiple
nozzles, multiple coolant reservoirs for a single refrigeration
unit, etc., examples of which are described in further detail
below.
[0164] As discussed above, costs may be also be reduced by
replacing conventional diffusion bonded (plate-to-plate) heat
exchangers with an annular heat exchanger that has been adapted to
operate in the high pressure and high UA hydrogen fueling
environment. By providing a lower cost high UA heat exchanger,
scalability and flexibility of a hydrogen cooling system can be
further improved. For example, conventional bonded heat exchangers
are costly, making employing a single heat exchanger a significant
expense that often renders scaling up cost prohibitive. By
contrast, an annular heat exchanger can be provided at
significantly reduced cost and facilitate configurations in which
an annular heat exchanger may be provided for each nozzle dispenser
at a fueling station, or shared between dispensers at each
refueling island, examples of which are described in further detail
below.
[0165] FIG. 14A illustrates an annular high UA heat exchanger for
hydrogen refueling using a shell-and-tube configuration, in
accordance with some embodiments. Exemplary annular high UA heat
exchanger 400 comprises a shell 410 through which coolant is
circulated via coolant inlet 415a and coolant outlet 415b in the
direction generally indicated by arrow 417. For example, coolant
from a coolant reservoir may be pumped in via inlet and 415a and
returned to the reservoir or provided to a chiller via outlet 415b,
depending on the configuration of the hydrogen cooling system. As
shown in FIG. 14B, a coil 450 formed of a metal or metal alloy
tubing (e.g., nickel, nickel alloy, copper, copper alloy or another
type of alloy, etc.) is positioned within the shell through which
hydrogen gas is pumped via hydrogen inlet 405a and hydrogen outlet
405b. For example, hydrogen gas from the hydrogen gas source of the
fueling station may be pumped into coil 450 via inlet 405a in the
direction generally indicated by arrow 407 and provided via outlet
405b to a dispenser nozzle to refuel a HFCV. As illustrated
schematically by arrows 407 and 417, hydrogen gas and coolant are
pumped through heat exchanger 400 in a counter-flow arrangement to
facilitate heat transfer from the hydrogen gas to the coolant. Heat
exchanger 400 also includes PRD port 413 to and thermocouple
420.
[0166] FIG. 14B illustrates annular heat exchanger 400 without the
outer shell, illustrating the tubing of coil 450 wrapped about
baffle 460. By providing the tubing with multiple turns or wraps,
hydrogen gas can be pumped through a long length of tubing with
significant surface area exposure to coolant flowing through the
shell, allowing for high UA heat exchange in a relatively compact
space. According to some embodiments, the tubing for coil 450 has a
total length of between 30 and 50 feet and comprises between 20 and
35 turns or wraps. However, it should be appreciated that the
number of wraps of the tubing forming coil 450 may be configured to
meet the requirements of a given heat exchanger and are not limited
to the exemplary values provided herein. Heat exchanger 400 also
includes baffle 460 to force the coolant through a relatively tight
area, increasing both the velocity and turbulence of the coolant to
promote heat transfer and increase the heat transfer efficiency of
the heat exchanger. Baffle 460 may be provided with a series of
pilot holes to prevent air pockets or "dead zones" from forming
along the baffle that could reduce the heat transfer efficiency of
the exchanger.
[0167] FIG. 14C illustrates a view of tubing 450 showing a turn at
a inlet side of the coil to illustrate exemplary dimensions of the
tubing. As shown, tubing 450 has an outer diameter OD, inner
diameter ID and a wall thickness t. According to some embodiments,
tubing 450 has an outer diameter of between 4.5 and 5.5 inches, an
inner diameter of between 3 and 4 inches, and a thin wall thickness
between 0.03 and 0.08 inches, and more preferably between 0.04 and
0.06 inches (whereas conventional wall thicknesses are on the order
of 0.1 inches, which generally provides inefficient heat transfer
that is generally not sufficient for hydrogen refueling without
significantly increasing the length of the coil tubing) to increase
heat transfer efficiency. However, the dimensions of tubing 450 may
be scaled up or down and the individual parameters may be chosen to
meet the requirements of a given heat exchanger and are not limited
to the exemplary values described herein for the illustrative
embodiments illustrated.
[0168] FIGS. 14D and 14E illustrate top view and a side views of
heat exchanger 400, respectively, illustrating the positioning of
coil 450 within shell 410 that is wrapped about baffle 460 to
provide a high UA heat exchanger in accordance with some
embodiments. Heat exchanger 400 has a length L and a height H (that
includes the height of feet 470a and 470b). According to some
embodiments, the length L may be between 30 and 50 inches (e.g.,
approximately 38-39 inches) and the H is between 10 and 15 inches
(e.g., approximately 12-13 inches). However, the dimensions of heat
exchanger 400 may be chosen to meet the requirements of a given
heat exchanger and are not limited to the exemplary values
described for the exemplary embodiments illustrated herein.
[0169] According to some embodiments, coil 450 is made of a
material that is compatible with hydrogen and that is capable of
withstanding the pressure conditions of hydrogen refueling at thin
wall thickness, such as a nickel alloy or the like. For example, a
nickel alloy material is resistant to corrosion and is therefore
suitable for the hydrogen refueling environment. As discussed
above, to increase heat transfer efficiency, coil 450 may be
manufactured with a thin wall thickness (e.g., t equal to
approximately 0.044 inches) to reduce the amount of material
between the hydrogen and the coolant. Using a thin wall thickness
facilitates a more compact design for the heat exchanger by
reducing the length of tubing needed to achieve the amount of
cooling. For example, conventional tube thicknesses on the order of
0.1 inches required doubling or tripling the length of the tubing
needed to achieve suitable cooling for many hydrogen refueling
applications. Thin wall thickness for the tubing also reduces the
time to cool hydrogen to target temperatures. Hydrogen refueling
applications often have short windows (e.g., approximately 30
seconds) to hit the temperature target for the hydrogen and
providing a thin wall thickness for the tubing reduces the time to
cool the hydrogen to target.
[0170] In addition, coil 450 may be finned to increase the surface
area of the coil to substantially increase the heat transfer
efficiency. FIG. 15 illustrates a coil that has been finned to
create more surface area via which heat from the hydrogen gas
flowing through the tubing can be transferred to the coolant
flowing through the shell in which the coil is positioned (e.g., in
the exemplary configuration illustrated in FIGS. 14A-E). In
particular, circular or elliptical fins are attached
circumferentially to provide fins about the tubing that are spaced
apart along the length of the coil to provide additional surface
area for heat exchange between hydrogen gas pumped through the
tubing and coolant pumped through the shell. In the embodiment
illustrated in FIG. 15, copper fins (e.g., exemplary copper fins
455) are attached to tubing 450 to provide a plurality of
transverse fins around and in contact with the tubing at a
relatively small spacing along the length of the coil. According to
some embodiments, multiple fins 455 (or all of the fins) may be
formed by a single continuous coil that spirals about tubing 450 to
provide a finned coil for the heat exchanger. Finning coil 450 can
increase the heat transfer capacity from approximately 5 kW to 75
kW, facilitating the provision of a high UA heat exchanger for
hydrogen refueling.
[0171] Finning of tubing 450 may be achieved by attaching the fins
to the tubing using a brazing process. The inventors recognized
that high temperature brazing can result in annealing of the metal
during the brazing process, thereby reducing the strength of the
material resulting in the risk of rupturing during use under the
high-pressure conditions of hydrogen fueling. According to some
embodiments, a silver alloy braze is used that allows fins to be
attached to the tubing at relatively low temperatures that prevents
annealing of the metal materials during the brazing process,
thereby maintaining the integrity of the coil. A silver alloy braze
is also compatible with coil and fin materials, for example, nickel
alloy tubing and copper fins. According to some embodiments,
finning and bending of the tubing into a coil is performed during
the same process. Table I illustrates materials and parameters for
an exemplary coil (e.g., coil 450) for an annular high UA heat
exchanger suitable for hydrogen fueling applications, in accordance
with some embodiments. It should be appreciated that the materials
and values given in Table I are merely exemplary and that different
materials and different values may be used to provide the coil for
an annular high UA heat exchanger, as the aspects are not limit to
any particular choice of material, dimensions and/or values for the
coil.
TABLE-US-00001 TABLE I Tubing Material Nickel Alloy Total Length 35
feet Coil Length 17.375 inches Number of Wraps 27 Pitch .625 inches
Outer Diameter 4.9 inches Inner Diameter 3.6 inches Wall Thickness
.044 inches Fin Material Copper Braze Silver Alloy Heat Transfer
Capacity 75 kW
[0172] According to some embodiments, an annular heat exchanger is
provided without the outer shell (FIGS. 16C, 16D) and/or without a
baffle (FIGS. 16D, 16E) to facilitate different configurations of
heat exchangers, examples of which are described in further detail
below. FIG. 16A illustrates the cross-section of an annular high UA
heat exchanger illustrating the annular configuration of heat
exchanger 400 illustrated in FIGS. 14A-F. In particular, the
exemplary configuration illustrated in FIG. 16A comprises outer
shell 410 containing heat exchanger coil 450 positioned about
baffle 460. The return tube 455 for the cooled hydrogen gas is
passed through the center of heat exchanger and provided to the
outlet of the heat exchanger for dispensing to the vehicle. FIG.
16B illustrates the cross-section of an annular high UA heat
exchanger having an outer coil 450a and an inner coil 450b to
increase the heat transfer capacity of the annular heat exchanger.
The components of the heat exchanger whose cross-section is
illustrated in FIG. 16B may be scaled up to provide a larger-sized
heat exchanger with increased heat transfer capacity for fueling
stations having higher performance requirements (e.g., fueling
stations for some medium-duty or heavy-duty installations for which
very high performance is needed).
[0173] FIGS. 16C and 16D illustrate the cross-section of
embodiments of annular heat exchangers without an outer shell for
the single coil and multiple coil configurations, respectively. In
particular, the cross-section of the annular heat exchanger
illustrated in FIG. 16C comprises a coil 450 and baffle 460 with
the return path 455 for the hydrogen passing through the center,
and the cross-section of the annular heat exchanger illustrated in
FIG. 16C comprises outer coil 450a and inner coil 450b, both
implemented without an outer shell. FIGS. 16D and 16E illustrate
the cross-section of embodiments of annular heat exchangers both
without an outer shell and a baffle for the single coil and
multiple coil configurations, respectively. In particular, the
cross-section of the annular heat exchanger illustrated in FIG. 16D
comprises a coil 450 with the return path for the hydrogen passing
through the center, and the cross-section of the annular heat
exchanger illustrated in FIG. 16E comprises outer coil 450a and
inner coil 450b, both without and outer shell or baffle. It should
be appreciated that multiple coil configurations may have
additional coils, as the aspects are not limited to the number of
coils provided. The coils may be formed using any of the techniques
described above in any combination.
[0174] As discussed above, annular high UA heat exchangers
facilitate reducing the cost of a hydrogen cooling system of a
fueling station. Additionally, the reduced cost annular heat
exchanger improves the flexibility and/or scalability of a hydrogen
cooling system that can be configured to meet the needs and
requirements of a given fueling station. FIG. 18 illustrates a
hydrogen fueling system utilizing a hydrogen cooling system
comprising a refrigeration unit configured to provide cooling for a
coolant reservoir that is shared by multiple dispensers, wherein
each dispenser has a respective high UA heat exchanger, which are
preferably annular heat exchangers configured according to one or
more techniques described in the foregoing. In particular, a
dispenser island 1800 of a fueling station comprises a first
dispenser 1820a and a second dispenser 1820b. A large-volume
coolant reservoir 814 comprising insulated tank 817 capable of
holding a large volume of coolant (e.g., a 50-600 gallon tank, and
more preferably between 80-120 gallons) is positioned between the
first and second dispensers to store coolant to chill hydrogen gas
prior to being dispensed by dispensers 1820a and 1820b to a fuel
tank of an HFCV. A single small-capacity refrigeration unit 812
(e.g., a refrigeration unit having a heat rejection capacity of
between 1 kW and 21 kW, and more preferably less than 10 kW) is
provided for dispenser island 1800 to maintain the coolant at low
temperatures via refrigeration coil 813 (e.g., between -40.degree.
C. and -17.5.degree. C.). Refrigeration unit 812 may be sized to
handle the average load of the fueling station because the
large-volume insulated tank operates as a substantial thermal
buffer. For example, a fueling station with a relatively small
average load may implement the hydrogen cooling system using a 1 kW
capacity refrigeration unit, while a fueling station with larger
average loads may implement the hydrogen cooling system using a
higher capacity refrigeration unit (e.g., 3 kW, 7 kW, 10 kW, etc.)
depending on the average load of the fueling station and/or on the
performance requirements of the fueling station. In this way, the
hydrogen cooling system can be scaled up to meet the needs of a
given fueling station. According to some embodiments, the
small-capacity refrigeration unit may be sized to up to 21 kW
(e.g., 12 kW, 15 kW, 20 kW, etc.) and the reservoir may be sized up
to 600 gallons or more for some medium or heavy-duty fueling
applications.
[0175] The hydrogen cooling system further comprises an annular
high UA heat exchanger for each of dispensers 1820a and 1820b.
Specifically, in the exemplary embodiment illustrated in FIG. 18,
annular heat exchanger 816a is fluidly coupled to dispenser 1820a
and annular heat exchanger 816b is fluidly coupled to dispenser
1820b so that chilled hydrogen can be dispensed via nozzles 1825a
and 1825b, respectively. To provide hydrogen gas at targeted
temperatures for refueling, each heat exchanger 816a, 816b is also
fluidly coupled to a hydrogen gas source 805 at the fueling station
and coupled to coolant held in insulated tank 817 of coolant
reservoir 814 shared by dispensers 1825a and 1825b. Coolant
reservoir 815 may comprise one or more pumps 815 that circulate
chilled coolant held in insulated tank 817 through the heat
exchangers. One or more pumps may also be provided to pump hydrogen
gas from hydrogen gas source 805 through heat exchangers 816a and
816b when respective dispenser nozzles 1825a and 1825b are engaged
with the fuel tank of an HFCV for fueling and/or hydrogen gas may
flow through heat exchangers 1825a and 1825b via the pressure
gradient at hydrogen source 805. In the exemplary embodiment
illustrated in FIG. 18, the heat exchangers are illustrated as
located within the insulated tank. However, the heat exchanger may
be located external to the reservoir (e.g., as illustrated in FIG.
11). Placement of the heat exchanger (e.g., internal or external to
the tank) may depend on the specific design configuration of a
particular fueling station, and the aspects are not limited to any
particular placement of the heat exchangers.
[0176] As discussed above, heat exchanger 816a, 816b are preferably
annular heat exchangers including any one or combination of
features described herein. According to some embodiments, heat
exchangers 816a and 816b may comprise a finned coil of tubing made
of a material compatible with hydrogen (e.g., nickel alloy tubing
with copper fins) designed for high heat transfer efficiency. For
example, the coil of tubing may be formed with thin walls (e.g.,
less than 0.07 inches, and more preferably less than 0.05 inches)
to facilitate a high heat transfer of capacity (e.g., a heat
transfer capacity of greater than 25 kW and more preferably greater
than 50 kW, such as a heat transfer capacity of approximately 75 kW
or more). According to some embodiments, annular heat exchangers
816a and 816b each comprise multiple coils to increase the heat
transfer capacity of the heat exchanger. It should be appreciated
that heat exchangers 816a and 816b may be dimensioned in any manner
suitable for the given fueling station, as the aspects are not
limited to any specific annular heat exchanger design.
Additionally, heat exchangers 816a and 816b may have the same or
different design from one another to achieve desired dispensing
characteristics of the dispenser to which it is coupled.
[0177] Hydrogen gas source 805 may be one or more hydrogen gas
storage tanks shared by all of the dispensers at the fueling
station, shared by a subset of the dispensers at the fueling
station or may comprise multiple individual hydrogen gas storage
tanks at each of the dispensers (which may in turn receive hydrogen
gas from a primary hydrogen storage tank or source, or may be
standalone dispenser units), as the aspects are not limited to any
particular configuration for the hydrogen gas source. In the
exemplary embodiment illustrated in FIG. 18, dispensers 1820a and
1820b are separate dispenser units (e.g., implemented within
separate housings and separate dispenser controllers), however,
according to some embodiments, dispensers 1820a and 1820b may be
implemented as a single unit (e.g., within a single housing) having
multiple nozzles, as the aspects are not limited in this respect.
Dispenser 1820a and 1820b may be conventional dispensers or may be
dispensers configured with the innovative dispenser controllers
and/or valves described in further detail below. The
above-described configuration provides a compact hydrogen cooling
system that can be implemented on a per island basis to provide
hydrogen cooling for multiple nozzles. This configuration may be
repeated for each island at the fueling station. According to some
embodiments, refrigeration unit 812 may be integrated in a single
housing with reservoir 914 between the dispensers, may be
positioned adjacent to reservoir 914, or reservoir 914 may be
integrated within refrigeration unit 812 (e.g., as illustrated in
FIG. 17), as the aspects are not limited in this respect. According
to some embodiments, refrigeration unit 812 may be coupled to
reservoirs at more than one island. It should be appreciated that
the components of the hydrogen fueling system illustrated in FIG.
18 (as with all of the systems described herein) are not drawn to
scale and are not intended to indicate relative sizes of the
components, but rather to show the coupling and arrangement of
these components.
[0178] The hydrogen cooling system may either be coupled upstream
or downstream from flow control valves 1880a and 1880b of the
respective dispensers. The two different hydrogen flow paths for
upstream and downstream configuration are illustrated in solid and
dotted lines, respectively. Specifically, as shown by the solid
lines, according to some embodiments in which the hydrogen cooling
system is coupled upstream of the flow control valve, hydrogen gas
from hydrogen gas source 805 is provided to the inlet of heat
exchangers 816a, 816b and chilled hydrogen gas from the heat
exchangers is provided to flow control valves 1880a and 1880b,
respectively. Chilled hydrogen gas flowing through the flow control
valves is provided to nozzle 1825a and 1825b for dispensing to a
vehicle during a fueling event. As shown by the dotted lines,
according to some embodiments the hydrogen cooling system is
coupled downstream of the flow control valve, hydrogen gas from
hydrogen gas source 805 is provided to flow control valves 1880a,
1880b and hydrogen gas flowing through the flow control valves is
provided to the inlet of heat exchangers 816a, 816b respectively.
Chilled hydrogen gas from the heat exchangers is provided to
dispenser nozzles 1825a, 1825b for dispensing to a vehicle during a
hydrogen fueling event. This solid and dotted line convention is
also used in the embodiments illustrated herein to illustrate that
either upstream or downstream coupling of a hydrogen cooling system
can be used in any configuration that utilizes a hydrogen cooling
system. As used herein, when a heat exchanger is described as
providing hydrogen gas to the dispenser, it refers to both upstream
configurations in which hydrogen gas from the heat exchanger is
provided to the dispenser upstream of the flow control valve and
downstream configuration in which hydrogen gas from the heat
exchanger is provided to the dispenser downstream of the flow
control valve.
[0179] FIG. 19 illustrates a hydrogen fueling system utilizing a
hydrogen cooling system comprising a refrigeration unit configured
to provide cooling for a coolant reservoir that is shared by
multiple dispensers, in accordance with some embodiments. The
exemplary hydrogen fueling system illustrated in FIG. 19 may be
similar in one or more respects to the hydrogen fueling system
described in connection with FIG. 18. In FIG. 19, a small-capacity
refrigeration unit 912 is provided to chill coolant (e.g., via
refrigeration coil 913) held in large-volume reservoir 914
comprising insulated tank 917 shared by dispensers 1920a and 1920b
on dispenser island 1900. In the embodiment illustrated in FIG. 19,
dispensers 1920a and dispenser 1920b share a single heat exchanger
916. Specifically, a single heat exchanger is fluidly coupled to
hydrogen source 905 and coupled to coolant held in tank 917 to
chill hydrogen gas when hydrogen from hydrogen source 905 and
coolant from the tank circulate through the heat exchanger. An
outlet of heat exchanger 916 is fluidly coupled to both dispensers
to provide chilled hydrogen to nozzles 1925a and 1925b for
refueling. The individual components of the hydrogen refueling
system illustrated in FIG. 19 may be implemented using any of the
techniques described herein. According to some embodiments, heat
exchanger 916 may be a high UA annular heat exchanger (e.g., any of
the annular heat exchangers described in the foregoing) to provide
a lower cost solution to chilling hydrogen). However, according to
some embodiments, heat exchanger 916 may be another type of high UA
heat exchanger such as a diffusion-bonded heat exchanger, as the
aspects are not limited in this respect. The components of the
hydrogen cooling system can be arranged apart, proximate or
adjacent, in the same housing or integrated together in any of the
configurations discussed in the foregoing (e.g., as described in
connection with the hydrogen fueling station illustrated in FIG.
19).
[0180] FIG. 20 illustrates a hydrogen fueling system utilizing
hydrogen cooling system comprising a refrigeration unit configured
to provide cooling for a plurality of coolant reservoirs
corresponding to respective dispensers, in accordance with some
embodiments. The exemplary hydrogen fueling system illustrated in
FIG. 20 may comprise individual components that are the same as or
similar to the components described in connection with FIGS. 18 and
19 that are sized appropriately for the configuration illustrated
in FIG. 20. In this configuration, a small-capacity refrigeration
unit 2012 is coupled to a first coolant reservoir 2014a comprising
insulated tank 2017a and a second coolant reservoir 2014b
comprising insulated tank 2017b, each coolant reservoir servicing a
respective dispenser 2020a and 2020b. Each of dispensers 2020a and
2020b has its own heat exchanger 2016a, 2016b (preferably of the
annular heat exchanger type), respectively, to chill hydrogen gas
from hydrogen source 2005 and provide the chilled hydrogen to
respective dispenser nozzle's 2025a and 2025b.
[0181] As discussed above, it should be appreciated that the
exemplary hydrogen fueling systems shown in FIGS. 18-20 are
illustrated schematically and the relative sizes of the components
are not drawn to scale but are intended instead merely illustrate a
set of components and coupling therebetween to illustrate an
exemplary configuration using one or more aspects of the techniques
developed by the inventors to implement a flexible and highly
scalable hydrogen cooling system for a wide range of hydrogen
fueling applications from light duty to medium and heavy duty
deployments. It should be further appreciated that the
small-capacity refrigeration unit, large-volume coolant reservoir
and high UA heat exchanger combination of components is amenable to
other configurations suitable for a given fueling station and that
the components can be sized and configured as discussed herein to
scale up or down to meet the performance requirements of a
particular fueling station installment.
[0182] As discussed above, the inventors have further appreciated
that the thermal energy capacity of a hydrogen cooling system may
be increased by using phase change materials (PCM) as a coolant,
either alone or in conjunction with one or more other coolants. As
also discussed above, phase change materials store energy when
cooled so that the material transitions from one state to another
(e.g., from a liquid to a solid, or from a gas to a liquid) that
can be released upon when the material is heated so as to
transition back to the previous state (e.g., from a solid to a
liquid, or from a liquid to a gas). As a result, heat transferred
from hydrogen gas during the chilling process for a fueling event
goes into state change rather than heating up the material. Thus, a
PCM coolant can be used like a thermal battery that can be
"charged-up" by causing it to transition from its ambient
temperature state to its low temperature state, and that stored
thermal energy can be released as the PCM absorbs heat from
hydrogen gas (or another coolant that has absorbed heat from
hydrogen gas) that goes into changing the state of the PCM back to
its ambient temperature state. Therefore, a reservoir of PCM
material can absorb more heat from hydrogen gas (or another coolant
that has absorbed heat from hydrogen gas) without increasing its
temperature, allowing for longer periods of continuous hydrogen
chilling without needing to recover the temperature of the PCM
and/or other coolant in the reservoir.
[0183] In addition, PCM material provides better thermal control
over the hydrogen gas because it will maintain the temperature of
its low temperature state transition until the material has
transitioned back to its ambient temperature state. As discussed
above, back-to-back fills (i.e., without a recovery period) using
conventional coolants result in increasingly higher temperature
hydrogen gas fills until the maximum temperature at which hydrogen
gas can be dispensed is reached and no further fueling can take
place until the refrigeration unit recovers the target temperature
of the coolant in the reservoir. Because the temperature of the PCM
will be maintained at its low temperature state transition
temperature, back-to-back fills can be performed at that
temperature until the PCM has been thoroughly transitioned to its
ambient temperature state.
[0184] The inventors have recognized that PCMs can therefore be
used to optimize the hydrogen cooling system for specific hydrogen
fueling needs in a number of ways, including increasing the number
of back-to-back fills that can be performed, reducing the size of
the coolant reservoir, reducing the size of the refrigeration unit
(which can be operated during the night or other off-peak hours
when demand is low and/or energy is cheaper to bring the PCM to its
low temperature state), or some combination of the above, as
discussed in further detail below.
[0185] FIG. 21 illustrates an example a hydrogen cooling system
using a PCM as a coolant to chill hydrogen gas, in accordance with
some embodiments. Hydrogen cooling system 2100 comprises a
refrigeration unit 2112 that chills coolant stored in a reservoir
2114 comprising insulated tank 2117 to hold PCM coolant, components
that may be similar or the same as, or different from, those
described in the foregoing and that, in accordance with some
embodiments, can be optimally sized in different ways as a result
of the use of PCM. Refrigeration unit 2112 is configured to chill
the PCM coolant to a temperature that causes the PCM to transition
to its low temperature state, e.g., via refrigeration coil 2113 or
via any other refrigeration techniques, thereby storing energy by
the transition of the PCM to its low temperature state.
[0186] According to some embodiments, the PCM's low temperature
state is as a solid so that refrigeration unit 2112 freezes the PCM
material to bring the reservoir down to the target temperature. In
such embodiments, heat exchanger 2116 may be an annular heat
exchanger comprising one or more coils according to techniques
described herein, but with no outer shell (e.g., as shown in the
exemplary configurations illustrated in FIGS. 16C-F. In such a
configuration, the coil(s) of heat exchanger 2116 may be positioned
within the reservoir in contact with the PCM that in the low
temperature state will form a solid mass about the coil to absorb
heat from hydrogen gas provided by a hydrogen gas source to an
inlet of the heat exchanger to provide chilled hydrogen gas to one
or more dispensers of a fueling station. As discussed above, the
use of a PCM reservoir allows an increased number of back-to-back
fills to be achieved without increasing the temperature of the PCM
due to the increased thermal capacity of the PCM (i.e., absorbed
heat energy goes into changing the state of the PCM instead of
increasing its temperature). The increased thermal capacity of the
PCM reservoir also allows the volume of the reservoir to be reduced
and/or the capacity of the refrigeration unit 2112 to be reduced,
thereby providing a more compact and/or less expensive hydrogen
cooling system. According to some embodiments, the PCM is a
eutectic compound (e.g., a mixture of materials) that has a state
transition at approximately the temperature of the lowest
temperature class fill at which the dispenser is configured to
dispense hydrogen gas (e.g., approximately -40.degree. C. for T40
class fills). However, it should be appreciated that such PCMs may
be chosen to have other low temperature state transitions (e.g.,
less than -10.degree. C., less than or equal to -20.degree. C.,
less than or equal to -30.degree. C., less than or equal to
-40.degree. C., etc.), as the aspects are not limited in this
respect.
[0187] With respect to the refrigeration unit 2112, because the PCM
reservoir does not need to be brought back to the target
temperature as frequently, a smaller capacity refrigeration unit
can be utilized and operated relatively infrequently when the PCM
reservoir needs to be brought back to its low temperature state.
For example, the refrigeration unit may be operated overnight or
during off hours (e.g., when energy is cheaper), when substantially
all of the PCM has transitioned to its ambient temperature state
(e.g., before or after the temperature of the ambient PCM has
reached a temperature in which no further low temperature fills can
be performed) and/or when the fueling station determines recovering
the temperature and/or low temperature state of the PCM is needed
via the vehicle communication techniques described above. The above
described benefits (increasing the back-to-back fill capacity,
reducing the volume of the reservoir, reducing the capacity of the
refrigeration unit, increasing the number of reservoirs coupled to
the refrigeration unit and/or increasing the number of dispenser
nozzles sharing the reservoir) can be used in any combination, thus
providing a highly flexible and modular hydrogen cooling system
that can meet the needs of a wide variety of fueling stations,
including providing different configurations of components for
different dispenser islands within the same fueling station,
providing multiple independent hydrogen cooling systems within the
same fueling station, or a single hydrogen cooling system
configured for light, medium or heavy duty refueling needs.
[0188] The inventors have further recognized that PCMs can be used
in combination with conventional coolants in a variety of ways to
take advantage of the increased thermal capacity of PCMs. According
to some embodiments, a dual-stage hydrogen cooling system is
provided comprising a bulk PCM reservoir for storing a PCM to chill
hydrogen gas from a hydrogen source to a first temperature and a
polishing reservoir for storing a conventional (non-PCM) coolant
(e.g., glycol) to chill hydrogen gas from the bulk PCM reservoir to
a second temperature for dispensing to a HFCV during a fueling
event. According to some embodiments, a coolant reservoir combines
a conventional coolant and a PCM material to take advantage of the
increased thermal capacity of the PCM when brought to its low
temperature state. According to some embodiments, a PCM is
integrated into the heat exchanger (e.g., within a baffle of
annular heat exchanger) configured to also circulate a conventional
coolant to chill hydrogen gas via both the integrated PCM and the
circulated conventional coolant. Examples of hydrogen cooling
systems utilizing one or more these techniques is discussed in
further detail.
[0189] FIG. 22 illustrates an exemplary dual-stage cooling system
comprising a bulk PCM reservoir 2214a that includes an insulated
tank 2217a for storing a PCM having a phase change at a first
temperature (e.g., between -20.degree. C. and -10.degree. C.,
between -10.degree. C. and 0.degree. C., etc.), and a polishing
reservoir 2214b that includes an insulated tank 2217b for storing a
conventional coolant. In the exemplary embodiment illustrated in
FIG. 22, a refrigeration unit 2112 is coupled to PCM reservoir
2214a to chill the PCM to cause a phase change of the PCM (e.g.,
via refrigeration coil 2213a) at the first temperature, and the
refrigeration unit 2112 is also coupled to polishing reservoir
2214b to chill the conventional coolant to a target temperature for
hydrogen gas dispensing (e.g., via refrigeration coil 2213b). Bulk
PCM reservoir 2214a may further comprise annular heat exchanger
2216a coupled to receive hydrogen gas from a hydrogen source (which
may either be a hydrogen gas storage tank or a dispenser depending
on whether hydrogen cooling is coupled upstream or downstream of
the dispenser flow control valve) and provide chilled hydrogen at
the first temperature via heat exchange between the hydrogen gas
and the PCM as the hydrogen gas flows through one or more coils of
heat exchanger 2216a. A second annular heat exchanger 2216b may be
coupled to coolant held by polishing reservoir 2214b and hydrogen
gas provided by annular heat exchanger 2216a to chill the hydrogen
gas from the first temperature to a target temperature for
dispensing to an HFCV. Second annular heat exchanger may be
deployed internal to polishing reservoir 2214b or may be deployed
external to the polishing reservoir as discussed in the
foregoing.
[0190] Annular heat exchanger 2216a may be formed using one or more
coils using any of the techniques described above so that the one
or more coils are thermally coupled to the PCM (e.g., in contact
with the PCM), for example, using the annular configurations
illustrated in FIGS. 16C-F that do not include an outer shell.
Thus, for exemplary dual-stage hydrogen cooling system 2200, a
first stage chills hydrogen gas from hydrogen gas source to a first
intermediate temperature between the temperature of the stored
hydrogen gas at the source and the target temperature for
dispensing to a HFCV, and a second stage chills hydrogen gas from
the intermediate temperature to the target temperature for
dispensing. The use of a bulk PCM reservoir for chilling hydrogen
to an intermediate temperature allows generally less expensive PCMs
to be used and allows for flexibility in the choice of PCM. Because
polishing reservoir need only reduce the temperature of hydrogen
gas from the intermediate temperature to the target temperature
rather than all the way from the temperature of the hydrogen gas
from the hydrogen source, each fueling event requires less energy
to cool the hydrogen gas, reducing the temperature increase of the
coolant from each fill, thereby decreasing recovery times and
increasing the back-to-back fill capacity of the hydrogen cooling
system.
[0191] In the exemplary embodiment illustrated FIG. 22, a single
refrigeration unit is employed to chill both the bulk PCM reservoir
and the polishing reservoir. However, according to some
embodiments, different refrigeration units are used to chill the
bulk PCM reservoir and the polishing reservoir, respectively, or
different stages of a multi-stage (e.g., cascaded) refrigeration
unit may be used to chill the different stages of the hydrogen
cooling system. Additionally, it should be appreciated that the
coupling of the refrigeration unit 2112 to the reservoirs
illustrated in FIG. 22 is schematic to illustrate that
refrigeration unit 2112 provides refrigeration for both reservoirs,
but that refrigeration unit 2112 may be coupled to stages of the
hydrogen cooling system so that the reservoirs can be chilled
independently of one another. For example, refrigeration unit 2112
may be independently coupled to bulk PCM reservoir 2214a and
polishing reservoir 2214b so that the stages can be independently
cooled. Because bulk PCM reservoir 2214a may only need to
infrequently recover the low temperature state of the PCM, it may
be advantageous to be able to chill the bulk PCM reservoir and the
polishing reservoir independently. According to some embodiments,
the stages of the hydrogen cooling system may be chilled
simultaneously, as the aspects are not limited in this respect.
[0192] According to some embodiments, a single bulk PCM reservoir
provides intermediate cooling for multiple polishing reservoirs.
For example, a single bulk PCM reservoir may provide intermediate
cooling for a plurality of polishing reservoirs where each of the
plurality of polishing reservoirs are shared by multiple dispensers
of a dispenser island, or where each of the plurality of polishing
reservoirs is used by a single respective dispenser. The
flexibility of dual-stage hydrogen cooling systems allows for many
different configurations and optimizations for both the sizing of
the one or more refrigeration units and for the volume of both the
PCM reservoir and the one or more polishing reservoirs to meet the
needs of a particular fueling station. It should be appreciated
that the use of a multi-stage cooling system can be implemented in
other configurations and the aspects are not limited to any
particular configuration, combination of elements and/or types of
PCM and conventional coolants.
[0193] FIG. 23 illustrates an exemplary annular heat exchanger
configured to hold a PCM internally to take advantage of the
increased thermal capacity of PCMs to chill hydrogen flowing
through one or more coils of the heat exchanger, in accordance with
some embodiments. Annular heat exchanger 2316 may share similar
aspects to the annular heat exchangers described in connection with
FIGS. 14D-E and 15. Specifically, exemplary annular heat exchanger
2316 comprises an outer shell 2310 through which coolant can be
circulated via coolant inlet 2315a and coolant outlet 2315b, and an
inner coil 2350 (e.g., a finned coil of tubing) through which
hydrogen gas can be circulated via hydrogen inlet 2305a and
hydrogen outlet 2305b. For annular heat exchanger 2316, inner
portion 2360 is configured to hold a PCM material 2321 (e.g., a
baffle may be configured to store PCM) such that inner coil 2350 is
thermally coupled to PCM 2321 when the inner portion 2360 contains
the PCM. As a result, hydrogen gas flowing through coil 2350
transfers heat to both conventional coolant circulating through the
heat exchanger and PCM 2321 held internally. It should be
appreciated that PCM may be held internal to the heat exchanger in
other ways, as the aspects are not limited in this respect.
[0194] FIG. 24 illustrates an exemplary hydrogen cooling system
that utilizes an annular heat exchanger of the type described above
in connection with FIG. 23, in accordance with some embodiments. In
particular, hydrogen cooling system 2400 comprises reservoir 2414
that includes insulated tank 2417 configured to hold a conventional
non-PCM coolant. Hydrogen cooling system 2400 further comprises
annular heat exchanger 2416 configured to hold a PCM material, for
example, using an inner portion of the heat exchanger as described
in connection with heat exchanger 2316 illustrated in FIG. 23. Heat
exchanger 2416 may be coupled to receive hydrogen gas from a
hydrogen gas source via an inlet to one or more coils of the heat
exchanger, and further coupled to receive non-PCM coolant from the
reservoir to circulate the coolant through the heat exchanger to
absorb heat energy from the hydrogen gas flowing through the
coil.
[0195] Refrigeration unit 2412 may be coupled to reservoir 2414 to
chill the non-PCM coolant in insulated tank 2417 (e.g., via
refrigeration coil 2413 or other refrigeration techniques) and the
PCM within heat exchanger 2416. When hydrogen gas and coolant are
pumped through heat exchanger 2416, heat from the hydrogen gas is
absorbed by the coolant and the PCM held internal to the heat
exchanger. As such, the heat transfer load of a fueling event will
be shared by the PCM and non-PCM coolants, resulting in a reduction
in the temperature increase of the non-PCM coolant in the
reservoir. Therefore, the exemplary PCM technique used by hydrogen
cooling system can be used to increase the back-to-back fill
capacity of the fueling system, decrease the recovery time of the
coolant reservoir, allow for a reduction in the size of the
refrigeration unit and/or volume of the reservoir, or facilitate an
optimization that achieves some combination of these benefits. It
should be appreciated that exemplary hydrogen cooling system 2400
may be used in any of the variety fueling system configurations
described herein (e.g., the hydrogen fueling systems illustrated in
FIGS. 18-21) allowing for further optimization and customization of
the resulting hydrogen fueling system.
[0196] FIG. 25 illustrates another exemplary hydrogen cooling
system utilizing PCMs to increase the thermal energy capacity of a
coolant reservoir, in accordance with some embodiments. Fueling
system 2500 may utilize a similar configuration as exemplary
fueling system 1700 described in connection with FIG. 17 in that a
coolant reservoir is integrated with a refrigeration unit to form
an integrated chiller system. In particular, in the embodiment
illustrated in FIG. 25, a chiller system includes a refrigeration
unit comprising an evaporator and a condenser that chills coolant
held in integrated reservoir 2514. Reservoir 2514 may be configured
to hold both a PCM and a conventional (non-PCM) coolant and chiller
system 2512 is arranged to chill both the PCM and the conventional
coolant held in the reservoir. For example, reservoir 2514 may
contain both a low temperature eutectic PCM and a conventional
coolant such as glycol that are chilled to a target temperature
that causes the PCM to transition to its low temperature state
(e.g., a solid). A heat exchanger 2516 may be coupled to chiller
system 2512 and hydrogen gas source 2505 to chill hydrogen gas with
coolant pumped from reservoir 2514 and circulated through the heat
exchanger via supply and returns lines. The chilled hydrogen gas
may then be provided to one or more dispensers 2520 for fueling of
HFCVs. The increased thermal energy capacity of the PCM is capable
of providing benefits described in the foregoing. It should be
appreciated that a coolant reservoir containing both PCM and
conventional coolant may be used in any of the other configurations
described above and is not limited for use in the integrated
chiller system illustrated in FIG. 25 (e.g., as a separate coolant
reservoir as illustrated in FIGS. 18-20, for example).
[0197] FIGS. 26A and 26B illustrate coaxial tubing that includes
PCM to facilitate aspects of hydrogen gas cooling, in accordance
with some embodiments. FIG. 26A illustrates a cross-section of
coaxial tubing 2675 that can be used to transport hydrogen from
components of a fueling station to one or more dispensers to
provide chilled hydrogen to dispensers for delivery to the fuel
tank of an HFCV during a fueling event. In the embodiment
illustrated in FIG. 26, coaxial tubing 2675 comprises three
concentric tubes: an inner tube 2650 through which hydrogen gas can
flow; a middle tube 2660 to contain a PCM; and outer tube 2670
through which a conventional (non-PCM) coolant can flow. Inner tube
2650 may be the same or similar to conventional piping used to
transport hydrogen between components of the fueling system or may
include a different type of tubing. It should be appreciated that
the relative diameters of the different tubing levels illustrated
in FIG. 26A is exemplary and tubing can be selected to have any
suitable diameters, as the aspects are not limited in this respect.
Using this configuration, hydrogen gas can be cooled as it flows
through the inner tube 2650 of coaxial tubing 2675.
[0198] In particular, hydrogen gas flowing through inner tube 2650
transfers heat to PCM contained in middle tube 2660 that has been
chilled to its low temperature state via chilled coolant flowing
through outer tube 2670. For example, coolant may be chilled to a
temperature sufficient to cause a state transition of the PCM to
its low temperature state using any of the refrigeration techniques
discussed herein and thereafter pumped through outer tube 2670 to
chill the PCM to cause a state transition. According to some
embodiments, coolant from a coolant reservoir that has been chilled
to a desired temperature by a refrigeration unit may be pumped
through outer tube 2670 to cause the PCM to change state and then
circulated back to the reservoir for temperature recovery. As
discussed above, once the PCM has been chilled to its low
temperature state, heat absorbed from hydrogen flowing through
inner tube 2650 will go into transitioning the PCM to its ambient
temperature state rather than heating the PCM. As a result, chilled
coolant may only need to be pumped through outer tube 2670 when the
PCM has substantially transitioned to its ambient temperature state
or when the fueling system determines that the low temperature
state of the PCM should be fully recovered.
[0199] FIG. 26B illustrates a hydrogen fueling system in which
coaxial tubing is employed to provide chilled hydrogen to one or
more dispensers for delivery to a fuel tank of an HFCV during a
fueling event. In the embodiment illustrated in FIG. 26B, hydrogen
fueling system 1600 comprises hydrogen gas source 2605, chiller
system 2612 and one or more dispensers 2620. Coaxial tubing 2675 is
fluidly coupled to components of the chiller system 2612 to
dispenser(s) 2620 to provide chilled hydrogen for dispensing.
Coaxial tubing 2675 may also be employed to transport hydrogen
directly from hydrogen source 2605 to the one or more dispensers,
as discussed in further detail below. Chiller system 2612 may
include any combination of refrigeration unit and coolant reservoir
described herein and may employ any of the cooling techniques
discussed above to provide chilled coolant to outer tube 2660 of
coaxial tubing 2675 at a sufficiently low temperature to cause PCM
contained in middle tube 2660 to transition to its low temperature
state. Heated coolant may be returned to chiller system 2612 via a
return line (not shown) or any suitable return path. The chilled
PCM absorbs heat from hydrogen gas from the hydrogen gas source
2605 as it flows through inner tube 2650 of coaxial tubing 2675 to
deliver chilled hydrogen to dispenser(s) 2620.
[0200] According to some embodiments, chiller system 2612 also
comprises a heat exchanger that pre-cools hydrogen gas from
hydrogen gas source 2605 before being provided to coaxial tubing
2675. In embodiments employing a heat exchanger, the heat transfer
load of chilling hydrogen gas may be shared between the heat
exchanger and coaxial tubing 2675 so that a lower UA heat exchanger
can be employed at reduced cost relative to embodiments of high UA
exchangers discussed herein. As discussed in connection with the
other PCM techniques discussed above, use of PCM in a coaxial
tubing facilitates increasing back-to-back fills, reducing the size
and cost of components of the hydrogen cooling system, or some
combination of each. According to some embodiments, coaxial tubing
2675 may be used to transport hydrogen gas from hydrogen gas source
2605 (e.g., one or more storage tanks) to the one or more
dispensers and chiller system 2612 may be coupled at the connection
of the coaxial tubing to the hydrogen gas source so that hydrogen
cooling may be performed via a direct transport link between the
hydrogen gas source 2650 and the one or more dispensers. Coaxial
tubing 2675 may be used to connect components of a hydrogen fueling
station in other ways, as the use of coaxial tubing is not limited
to any particular arrangement.
[0201] As discussed above, a fueling event includes a dispenser at
a hydrogen fueling station delivering hydrogen from a hydrogen
source at the fueling station to a fuel tank onboard a HFCV. When
the nozzle of the dispenser is engaged with the vehicle fuel tank,
the dispenser is activated to control the flow of hydrogen into the
fuel tank of the vehicle. As discussed above, tank parameters such
as tank pressure, tank volume, tank temperature, etc. are typically
communicated to the dispenser so that the dispenser can safely
refill the tank. Fueling protocols are established for safely
refueling a HFCV and dispensers are configured to control the flow
of gas into the tank according to a corresponding fueling protocol.
FIG. 27 illustrates a typical fueling protocol for an HFCV. During
a startup up time, the dispenser delivers gas to perform certain
start actions. After the start-up time, the dispenser will enter an
active filling stage in which the dispenser attempts to maintain a
constant pressure ramp rate to the vehicle as illustrated by the
linear ramp of the pressure profile between the start and end of
fueling points of the exemplary fueling protocol illustrated in
FIG. 27, which is interrupted by two dwell time safety checks in
which the dispenser is required to stop the flow of hydrogen to
ensure there is no leaking. Fueling protocols typically specify a
tolerance (referred to as the pressure corridor) that a dispenser
is allowed to deviate from the specified pressure profile of the
fueling protocol (e.g., between +7 MPa/min and -2 MPA/min from the
target pressure profile of the fueling protocol. Thus, hydrogen
fueling involves controlling the dispenser to maintain a constant
pressure ramp (e.g., bar per minute) as opposed to maintain a
particular mass flow rate (e.g., kg per minute). Because hydrogen
is compressible, the mass flow rate of the hydrogen is not
constant. According, the dispenser must be able to control vary the
area through which hydrogen gas flows to allow the mass flow rate
to vary to maintain the desired pressure profile of the fueling
protocol. Some fueling protocols may provide target hydrogen flow
rates instead of or in addition to target pressures.
[0202] The inventors have developed dispenser techniques to
facilitate dispenser control of hydrogen gas to a fuel tank of a
HFCV. According to some embodiments, a dispenser comprises a bank
of fixed-sized orifice valves that can be turned off and on in any
desired combination to control the mass flow rate of hydrogen gas
to the vehicle to achieve the pressure profile (e.g., a constant
pressure ramp) of a fueling protocol. According to some
embodiments, a variable-size orifice solenoid valve paired to a
direct drive servo motor is employed to control the mass flow rate
of hydrogen to match the pressure profile of a corresponding
fueling protocol. As discussed above, either the fixed-sized
orifice solution or the variable-size orifice solution can be
employed in any of the dispenser illustrated above in connection
with the exemplary fueling stations.
[0203] FIG. 28 illustrates a fixed-orifice dispenser comprising a
valve bank of fixed-size orifice valves that can be controlled to
be open or closed to provide a desired flow area to achieve a
target pressure and/or target flow rate during a fueling event, in
accordance with some embodiments. As used herein, a fixed-size
orifice valve refers to an orifice having a fixed-size opening or
flow area paired with a valve that can be opened or closed.
According to some embodiments, a valve bank may include one or more
fixed-size orifices that are not paired with a valve. For example,
in addition to one or more fixed-size orifice valves, a valve bank
may include one or more fixed-size orifices such that when a
dispenser is enabled to dispense hydrogen gas (e.g., by opening a
master valve to the valve bank) a minimum flow rate of hydrogen
will be delivered to the nozzle via the one or more fixed-size
orifices without needing to open a respective associated valve.
[0204] In the embodiment illustrated in FIG. 28, exemplary
dispenser 2820 comprises valve bank 2880 that includes a plurality
of fixed-size orifice valves 2885a-2885e arranged in parallel that
can be turned on and off under control of dispenser controller
2890. As used herein, arranged in parallel means that the same
hydrogen gas does not flow through any of the fixed-size orifice
valves that are so arranged. As a result, the hydrogen gas provided
at output 2880b is the sum of the hydrogen gas flowing through the
fixed-size orifice valves that are arranged in parallel. A supply
of hydrogen gas, either from a hydrogen gas source directly for
ambient fills or in configurations in which hydrogen cooling is
performed downstream of valve bank 2880, or via a hydrogen cooling
system (e.g., any of the exemplary hydrogen cooling system
described herein) in configurations in which hydrogen cooling is
performed upstream of valve bank 2880, is provided to a main fuel
valve, which is turned on when dispenser nozzle 2825 is engaged
with the fuel tank interface 2811 of HFCV 2810 to provide hydrogen
gas at input 2880a of bank 2880. The flow of hydrogen gas is
governed by which of the fixed orifice valves the controller opens
to pass hydrogen gas from the supply to the dispenser nozzle 2825
and into the fuel tank of the HFCV.
[0205] According to some embodiments, dispenser controller 2890 is
configured to control the pressure of hydrogen gas dispensed to the
HFCV, for example, according to a pressure profile of a hydrogen
fueling protocol. Thus, dispenser controller receives the target
pressure 2892 (or target flow rate) indicative of the desired tank
pressure of the fuel tank of HFCV (or target flow rate to the tank)
at a given instant during the fueling event, which target pressure
and/or target flow rate may vary over the course of the fueling
event in accordance with the fueling protocol. To achieve the
desired pressure, controller 2890 may be configured to receive the
supply pressure 2891 of the hydrogen gas from the gas supply, a
measured pressure downstream of the valve bank and/or the tank
pressure of the fuel tank of the HFCV. As discussed above, tank
parameters may be received via a communications link established
between the nozzle and the fuel tank, via a communications link
established between the vehicle and a fueling station network
and/or or may be received via other means (e.g., tank pressure may
be measured directly by nozzle 2825). Thus, controller 2890 may
receive the tank pressure 2893 at a given instant in time. Using
the supply pressure 2891 and either the measured pressure 2894, the
tank pressure 2893, or both, and the known pressure differential
across each of the fixed orifices, controller 2890 determines which
combination of fixed orifices valves 2885a-e should be opened to
provide a hydrogen gas flow rate that most closely matches the
hydrogen gas flow rate that will deliver the target pressure 2892
(or target flow rate) to the tank (e.g., a constant pressure ramp
during the course of the fueling event). Controller 2890 may also
receive measurements from one or more sensors 2870 to ensure that
the dispenser is delivering the desired flow rate of hydrogen gas.
For example, sensor(s) 2870 may include a pressure sensor, a mass
flow rate sensor or both as a check to make sure that the hydrogen
gas is being delivered as intended.
[0206] It should be appreciated that bank 2880 may include any
number of fixed-size orifice valves of any size. For example, bank
2880 may include a plurality of orifices at different fixed sizes,
a plurality of orifices at a same size or any combination of
different and same size orifices to achieve the desired granularity
in control over the flow rate of hydrogen between the hydrogen
supply and the dispenser nozzle. Fixed-size orifice valves are
relatively inexpensive and have few moving parts and therefore can
provide a cost effective and reliable dispenser solution for
dispensing hydrogen gas to a HFCV vehicle. Additionally, valve bank
2880 may include one or more fixed-size orifices without an
associated valve that allows hydrogen flow whenever supply hydrogen
is provided to the valve bank 2880 (e.g., whenever the main fuel
valve of the dispenser is opened), some examples of which are
described in further detail below in connection with FIG. 30.
[0207] FIG. 29 illustrates a method of controlling hydrogen gas
flow during a fueling event using a valve bank containing a
plurality of fixed-size orifice valves arranged in parallel, in
accordance with some embodiments. In act 2910, a fueling event may
begin when, for example, a nozzle at a dispenser is engaged with
the fuel tank of a vehicle or a fuel event is otherwise initiated.
According to some embodiments, vehicle-to-nozzle pairing is
performed during act 2910 using any of the techniques discussed
herein, or vehicle-to-nozzle pairing may be performed using
conventional techniques (e.g., via IrDA when the dispenser nozzle
is engaged with the vehicle). In act 2920, the dispenser is
prepared to perform the fueling event and may include receiving
tank parameters from the vehicle, engaging relevant portions of a
hydrogen cooling system to provide chilled hydrogen gas, opening a
master valve to allow hydrogen gas from the supply (e.g., hydrogen
gas stored in a bank of storage tanks) to flow to the dispenser
(e.g., a stop flow valve of the valve bank of the dispenser),
obtaining a fueling protocol for the fueling event or any other
tasks to prepare the dispenser to perform the fueling event.
According to some embodiments, components of a hydrogen cooling
system are arranged upstream from the dispenser so that chilled
hydrogen is supplied to the dispenser. In some embodiments, one or
more components of a hydrogen cooling system (e.g., a heat
exchanger) are provided downstream from the dispenser flow control
system (e.g., downstream of the valve bank) prior to being
delivered to the nozzle so that the dispenser is supplied hydrogen
gas at approximately the temperature at which the hydrogen gas is
stored. To begin fueling, the dispenser controller may be
configured to allow a prescribed amount of hydrogen to flow through
the dispenser for delivery to the fuel tank of the vehicle via the
nozzle during a start-up period.
[0208] In act 2930, the dispenser controller receives or obtains
input from one or more sensors or otherwise receiving information
for the fueling event. For example, the dispenser may be configured
to receive supply pressure of the hydrogen gas at the input of the
dispenser, measured pressure and/or flow rate downstream of the
valve bank and/or tank pressure of the fuel tank of the vehicle,
and a target pressure of the fuel tank (or a flow rate to the tank)
that the dispenser controller seeks to achieve. As discussed in the
foregoing, the target pressure and/or hydrogen flow rate may be
obtained from a fueling protocol that provides a pressure profile
the dispenser should follow during the refueling event. The
dispenser controller may also obtain other input such as hydrogen
flow rate at or near the nozzle (e.g., downstream from the
dispenser valve system), temperature or other input in connection
with the fueling event.
[0209] In act 2940, the dispenser controller controls the plurality
of fixed-sized orifice valves based on the input received by the
dispenser controller including, but not limited to, opening one or
more of the plurality of fixed-size orifice valves, closing one or
more of the plurality of fixed-size orifice valves, or maintaining
the existing combination of open and closed fixed-sized orifice
valves to deliver hydrogen flow through the valve bank that matches
the target pressure and/or target flow rate or follows the target
pressure profile as closely as possible. According to some
embodiments, the dispenser controller uses the supply pressure of
hydrogen gas at or near the input to the valve bank (upstream of
the valve bank), the measured pressure and/or flow rate downstream
of the valve bank and/or the current tank pressure of the fuel tank
of the vehicle, and the current target pressure and/or hydrogen
flow rate to determine the combination of open and closed
fixed-size orifice valves that will deliver hydrogen at a flow rate
that will result in bringing the measured pressure or tank pressure
towards the target pressure or the target flow, respectively. For
example, the dispenser controller may use the difference between
the measured pressure and/or current tank pressure and the current
target pressure to selectively open or close one or more of the
fixed-size orifice valves or maintain the current combination of
open and closed valves to minimize the difference between the
current tank pressure and the current target pressure. However, the
dispenser controller can determine the combination of open and
closed fixed-size orifice valves in other suitable ways to follow a
target pressure and/or flow rate profile for the fueling event. The
dispenser controller may be configured to continuously monitor the
input received (e.g., received in act 2930) to control the valve
bank to adjust the hydrogen flow rate to follow the target pressure
and/or flow rate profile for the fueling event until the fill is
complete (act 2945).
[0210] A fill may be completed when the nozzle is disengaged from
the fuel tank, the dispenser determines that the fuel tank is full
(e.g., the tank pressure has reached its maximum tank pressure), or
the dispenser otherwise determines that the delivery of hydrogen
gas should be terminated. To end the fueling event (act 2950), the
dispenser controller may close the master valve (e.g., stop flow
valve) to the valve bank, close the plurality of fixed-sized
orifice valves, or otherwise stop the dispensing of hydrogen gas to
the fuel tank of the vehicle. By using the supply pressure,
measured pressure and/or current tank pressure and target pressure
and/or target flow rate to control the fueling event, the dispenser
can perform a fueling event according to a desired fueling protocol
to the resolution of the valve bank based on the number of valves
and/or combination of different orifice sizes, which can be
designed to achieve a desired granularity in different flow
rates.
[0211] FIG. 30 illustrates a hydrogen fueling system comprising a
dispenser utilizing a valve bank of fixed-size orifice valves
implementing a dual-nozzle configuration, in accordance with some
embodiments. Hydrogen fueling system 3000 comprises a dispenser
3020 that controls flow of hydrogen gas to a pair of nozzles
configured for performing fueling events for two different types of
vehicles. According to some embodiments, dispenser 3020 may be
configured with two separate flow paths to deliver hydrogen gas to
nozzle 3025a configured for use with a first type of vehicle (e.g.,
cargo trucks, etc.) and to deliver hydrogen gas to nozzle 3025b
configured for use with a second type of vehicle (e.g., passenger
busses). It should be appreciated that the dual nozzle
configuration can be configured to deliver hydrogen to any type of
vehicle, as the aspects are not limited in this respect.
[0212] In the embodiment illustrated in FIG. 30, valve bank 3080
comprises fixed-size orifice valves 3085a and 3085b, fixed-size
orifice 3084 and full flow valve 3083. According to one example
configuration, the size of the orifice for fixed-size orifice valve
3085a may be 0.038 inches (allowing 750 grams/min of flow) and the
size of the orifices for fixed-size orifice valve 3085b and
fixed-size orifice 3084 may both be 0.022 inches (allowing 250
grams/min of flow). However, these values are merely exemplary and
any size orifices may be chosen depending on the requirements of
the dispenser. In the embodiment illustrated in FIG. 30, nozzles
3025a and 3025b may have an associated nozzle fixed-size orifice
valve 3085c and 3085d, respectively, that are sized according to
the type of vehicle that the nozzle is configured to refuel to
allow a maximum flow rate to be delivered to the nozzle. According
to some embodiments, the size of the orifice for fixed-size orifice
valve 3085c may be 0.058 inches (allowing for a maximum flow rate
of 1800 grams/min) and the size of the orifice for fixed-size
orifice valve 3085d may be 0.082 inches (allowing for a maximum
flow rate of 3600 grams/min). Fixed-size orifice 3084 has no
associated valve so that whenever stop flow valve 3005 is opened
and one of nozzle valves 3085c, 3085d is opened, a minimum flow
rate dictated by the size of this orifice (e.g., 250 g/min) will be
delivered to the corresponding nozzle. Full flow valve 3083 has no
associated orifice so that hydrogen gas will flow through the valve
bank at full flow and will be limited by the orifice of the nozzle
valve of whichever of nozzle 3025a, 3205b has been engaged with a
vehicle.
[0213] As one example fueling event using this configuration, all
of the valves may be closed to begin with and the either nozzle
valve 3085c or 3085d will be opened depending on which nozzle has
been engaged with a vehicle of the corresponding type. According to
some embodiments, the nozzles themselves are different so that they
cannot be mistakenly engaged with the wrong type of vehicle. When
stop flow valve 3005 is opened to begin the fueling event, hydrogen
gas will flow only through orifice 3084 at the maximum flow rate of
the orifice (e.g., 250 g/min). Dispenser controller 3090 may then
select which of fixed-size orifice valves 3085a, 3085b and/or full
flow valve 3083 to open to deliver hydrogen gas at different flow
rates ranging from the maximum flow rate of orifice 3084 to the
maximum flow rate of the nozzle valve 3085c, 3085d engaged with a
vehicle during the fueling event. For the exemplary orifice sizes
discussed above, dispenser controller 3090 can deliver a flow rate
of 250 g/min, 500 g/min, 1000 g/min, 1500 g/min and full flow rate
that is limited to 1800 g/min for nozzle 3025a and that is limited
to 3600 g/min for nozzle 3025b. However, it should be appreciated
that any number of fixed-size orifice valves of any size can be
used to delivered flow rates to any type of desired vehicle, as the
aspects the dual-nozzle dispenser configuration are not limited in
this respect.
[0214] According to some embodiments, a variable-size orifice valve
paired to a direct drive servo motor is employed to control the
mass flow rate of hydrogen to match the pressure profile of a
corresponding fueling protocol. Many conventional hydrogen flow
control valves employ pressure regulator valves that are opened and
closed pneumatically based on the pressure differential across the
valve. Pressure regulator valves are frequently used in hydrogen
fueling applications because there are no electrical components and
are by design safe for hydrogen fueling environments. The inventors
recognized that the use of pressure regulator valves have
drawbacks, some associated with slow response times to pressure
changes at the hydrogen gas supply. Typical hydrogen sources at a
fueling station comprise a bank of cascaded tanks at different
pressures that are successively opened during a fueling event. As a
result, the supply pressure will decrease as hydrogen flows from
the first tank and then will spike each time a successive tank is
engaged to deliver hydrogen. Conventional dispenser controllers
using pressure regulator valves typically cannot handle such large
changes in supply pressure and as a result are forced to stop the
flow of hydrogen gas, reset the pressure regulators and then start
the flow again. As a result, hydrogen fueling stations typically
must be paired with a specific dispenser tuned to the specific
storage bank at that fueling station, resulting in costly, time
consuming and inflexible deployment of a hydrogen dispenser that
must be matched to a specific fueling station. Some hydrogen gas
dispenser utilize stepper motors to open and close the valve
opening, but stepper motor solutions also suffer from slow response
times and lack of control.
[0215] According to some embodiments, a variable-size orifice valve
is paired with a direct drive servo motor providing high resolution
and highly responsive control over the variable-size orifice valve,
thereby addressing a number of drawbacks of conventional dispensers
that utilize variable-size orifice valves that are paired with
stepper motors and/or rely on pressure regulators to control
hydrogen flow into the fuel tank of an HFCV during a fueling event.
As used herein, a direct drive servo motor refers to a servo motor
that has a one-to-one rotational relationship with the valve to
which it is paired. That is, each 360.degree. rotation of the
direct drive servo motor results in a 360.degree. rotation of the
valve stem. By contrast, stepper motors or other geared motors have
a many-to-one rotational relationship with the valve to which it is
paired. That is, a 360.degree. rotation of the valve stem requires
multiple rotations of the stepper motor due to gear reduction. For
example, a typical stepper motor may have a twenty-to-one
rotational relationship with the valve so that the stepper motor
rotates twenty times (i.e., 7200.degree. of rotation) to effect one
rotation of the valve stem (i.e., 360.degree.). As a result,
pairing the valve with a direct driver servo motor results in
significantly fast response times. Additionally, direct drive servo
motors according to some embodiments can operate at significantly
higher rotations per minute (RPMs) than stepper motors, further
increasing the speed increase and responsive improvement over
conventional stepper motor solutions. That is, direct drive servo
motors according to some embodiments not only effect more change in
the valve opening on each rotation, but also rotate faster.
[0216] According to some embodiments, a direct drive servo motor
includes an encoder that measures the rotation of the direct drive
servo motor. Because the servo motor is direct drive, the encoder
allows the position of the valve to be measured (i.e., how many
degrees the valve has been opened). The measured valve position
allows the dispenser controller to operate in a closed feedback
loop, facilitating precise control and fast response times at a
high degree of resolution. According to some embodiments, the
encoder measures rotation with one degree of resolution or less
(0.5 degrees or less, more preferably 0.3 degrees or less, and more
preferably at 0.1 degrees of resolution), allowing the valve
position to be precisely determined. According to some embodiments,
the encodes measures rotation down to 0.1 degree of resolution,
allowing for highly precise control.
[0217] Hydrogen dispensers employing a flow control valve having a
direct drive servo motor paired with variable-size orifice valve
and control techniques described herein provide high resolution and
fast response times that allow the dispenser to be deployed at
virtually any fueling station independent of the characteristics of
the hydrogen gas source (e.g., independent of the characteristics
of the supply bank), eliminating the need to match and custom tune
the dispenser for a specific hydrogen supply bank or hydrogen
source configuration and allowing for the design of standalone
hydrogen dispensers that are agnostic to the fueling station
configuration and hydrogen supply characteristics, facilitating
simple cost effective deployment across a wide range of different
fueling stations. Because the flow control valve using the direct
drive servo motor techniques described herein can respond quickly
and precisely, the dispenser controller does not need to stop flow
when a different supply tank is switched to and the dispenser need
not know that specifics of the number, trigger levels or pressure
changes that will result from a particular storage bank because the
dispenser controller can respond quickly to pressure spikes and
continue to deliver hydrogen gas at the desired pressure.
[0218] FIG. 31 illustrates a dispenser employing a flow control
valve comprising a variable-size orifice valve paired with a direct
drive servo motor that can be controlled to vary the size of the
valve opening to provide a desired flow area that delivers a flow
rate that achieves a target pressure and/or target flow rate during
a fueling event, in accordance with some embodiments. In the
embodiment illustrated in FIG. 31, exemplary dispenser 3120 employs
flow control valve 3100 comprising a direct drive servo motor 3180
coupled to variable-size valve 3185 to vary the size of the valve
opening based on control signals 3195 from dispenser controller
3190. Dispenser 3120 may also include a stop flow valve 3105 that
is closed to stop hydrogen flow when the dispenser is not being
used and that is opened at the beginning of a fueling event. One or
more of the inputs to the dispenser 3120 and dispenser controller
3190 may be similar to or the same as those described in connection
the dispenser illustrated in FIG. 28. For example, a supply of
hydrogen gas, either from a hydrogen gas source directly for
ambient fills or in configurations in which hydrogen cooling is
performed downstream of valve 3185, or via a hydrogen cooling
system (e.g., any of the exemplary hydrogen cooling system
described herein) in configurations in which hydrogen cooling is
performed upstream of valve 3185 via a hydrogen cooling system
(e.g., any of the exemplary hydrogen cooling system described
herein), is provided to the dispenser when dispenser nozzle 3125 is
engaged with the fuel tank interface 3111 of HFCV 3110.
[0219] Dispenser controller 3190 may be configured to control the
pressure of hydrogen gas dispensed to the HFCV, for example,
according to a pressure profile of a hydrogen fueling protocol. For
example, dispenser controller 3190 may receive the target pressure
and/or target flow rate 3192 indicative of the desired tank
pressure of the fuel tank of HFCV and/or the desired flow rate to
be delivered at a given instant during the fueling event, which
target pressure and/or target flow rate may vary over the course of
the fueling event in accordance with the fueling protocol. To
achieve the desired pressure, controller 3190 may be configured to
receive the supply pressure 3191 of the hydrogen gas from the gas
supply, a measured pressure and/or measured flow rate downstream
from the flow control valve (e.g., measured by a sensor(s) in
sensor(s) 3170 and/or the tank pressure 3193 of the fuel tank of
the HFCV. As discussed above, tank parameters may be received via a
communications link established between the nozzle and the fuel
tank, via a communications link established between the vehicle and
a fueling station network and/or or may be received via other means
(e.g., tank pressure may be measured directly by nozzle 3125).
Thus, dispenser controller 3190 may receive the tank pressure 3193
at a given instant in time.
[0220] In the embodiment illustrated in FIG. 31, direct drive servo
motor includes an encoder that measures valve position 3183 (e.g.,
how many degrees the valve has been opened) and provides the valve
position measurement 3183 to dispenser controller 3190. Using the
supply pressure 3191, measured pressure and/or measured flow rate
3194 and/or tank pressure 3193, dispenser controller 3190
determines the flow area that achieves a hydrogen gas flow rate
that will deliver the target pressure and/or target flow rate 3192
to the tank (e.g., a constant pressure ramp during the course of
the fueling event). Because the dispenser controller can determine
the current flow area of the valve from the valve position
measurement (e.g., the area of the valve opening may be determined
from the number of degrees that the valve is opened using the known
valve characteristics), dispenser controller 3190 can provide
signal 3195 (e.g., a voltage or current signal) that will cause the
direct drive servo motor 3180 to precisely control valve 3185 to
achieve the determined flow area. Controller 3190 may also receive
measurements from one or more sensors 3170 to ensure that the
dispenser is delivering the desired flow rate of hydrogen gas. For
example, sensor(s) 3170 may include a pressure sensor (to provide
the measured pressure 3194), a mass flow rate sensor or both as a
check to make sure that the hydrogen gas is being delivered as
intended (or as part of the control feedback loop).
[0221] FIG. 32 illustrates a method of controlling hydrogen gas
flow during a fueling event using a variable-size valve paired with
a direct drive servo motor, in accordance with some embodiments.
Acts 3210 and 3220 may include some or all of the actions described
for act 2910 and 2920 in connection with the fueling method
illustrated in FIG. 29. For example, a fueling event may begin (act
3210) when, for example, a nozzle at a dispenser is engaged with
the fuel tank of a vehicle or a fuel event is otherwise initiated.
Vehicle-to-nozzle pairing may be performed using any suitable
technique. In act 3220, the dispenser may be prepared to perform
the fueling event by receiving tank parameters from the vehicle,
engaging relevant portions of a hydrogen cooling system to provide
chilled hydrogen gas, opening a master valve (e.g., a stop flow
valve) to allow hydrogen gas from the supply (e.g., hydrogen gas
stored in a bank of storage tanks) to flow to the dispenser,
obtaining a fueling protocol for the fueling event and/or any other
tasks to prepare the dispenser to perform the fueling event.
[0222] According to some embodiments, components of a hydrogen
cooling system are arranged upstream from the dispenser so that
chilled hydrogen is supplied to the dispenser. In some embodiments,
one or more components of a hydrogen cooling system (e.g., a heat
exchanger) are provided downstream from the dispenser flow control
system (e.g., downstream of the variable-size valve) prior to being
delivered to the nozzle so that the dispenser is supplied hydrogen
gas at approximately the temperature at which the hydrogen gas is
stored. To begin fueling, the dispenser controller may cause the
direct drive servo motor to open the valve a small amount (e.g.,
bring the valve to an almost closed position) and then slowly open
the valve until an initial target pressure and/or target flow rate
is achieved. By initially opening the valve slowly, large spikes
that could potentially overheat the tank or damage components of
the dispenser are prevented. Once the initial target pressure is
reached, the dispenser controller control loop follows a desired
pressure and/or target flow rate profile based on input received by
the dispenser controller in act 3230.
[0223] For example, the dispenser may be configured to receive
supply pressure of the hydrogen gas at the input of the dispenser,
measured pressure and/or flow rate downstream of the flow control
valve and/or tank pressure of the fuel tank of the vehicle, a
target pressure of the fuel tank (or target flow rate to be
delivered) that the dispenser controller seeks to achieve, flow
rate and feedback from the direct drive servo motor (e.g., valve
position from an encoder). As discussed in the foregoing, the
target pressure and/or target flow rate may be obtained from a
fueling protocol that provides a pressure and/or flow rate profile
the dispenser should follow during the fueling event. The dispenser
controller may also obtain other input such as the hydrogen gas
pressure and/or hydrogen flow rate at or near the nozzle (e.g.,
downstream from the dispenser valve system), or other input in
connection with the fueling event.
[0224] In act 3240, the dispenser controller sends signals to the
direct drive servo motor (e.g., voltage or current signals
indicative of the direction and amount that the direct drive servo
motor should change the valve position) based on the input received
in act 2930. According to some embodiments, the dispenser
controller uses the supply pressure of hydrogen gas at or near the
valve input, the measured pressure downstream of the flow control
valve and/or current tank pressure of the fuel tank of the vehicle,
the current target pressure and/or target flow rate, current flow
rate and valve position in a closed feedback loop to adjust the
valve position (e.g., via signals from the dispenser controller to
the direct drive servo motor) to deliver hydrogen gas at the target
pressure. As the target pressure and/or target flow changes (e.g.,
according to a fueling protocol) and/or as the supply pressure
changes, the feedback loop tracks the target pressure and/or flow
rate by adjusting the valve position accordingly until it is
determined that the fill is complete in act 3245, for example, when
the nozzle is disengaged from the fuel tank, the dispenser
determines that the fuel tank is full (e.g., the tank pressure has
reached its maximum tank pressure), or the dispenser otherwise
determines (or is instructed) that the delivery of hydrogen gas
should be terminated. To end the fueling event (act 3250), the
dispenser controller may signal the direct drive servo motor to
bring the valve to a fully closed position (and close any master
valve that may be present) and/or otherwise stop the dispensing of
hydrogen gas to the fuel tank of the vehicle.
[0225] FIG. 33 illustrate view of flow control valve comprising a
variable-size valve paired with direct drive servo motor, in
accordance with some embodiments. Exemplary flow control valve 3300
comprises a valve 3330 having a valve opening or orifice 3334 whose
size can be varied from fully closed to fully opened by rotating
valve stem 3335. A direct drive servo motor 3310 is coupled to
valve stem 3335 via valve coupling 3320 so that its rotation causes
valve stem 3335 to rotate to change the size of valve orifice 3334.
Hydrogen gas flows through the valve orifice via inlet 3332a and
3332b. As discussed above, a direct drive servo motor has a
one-to-one rotational relationship with valve so that each
360.degree. rotation of the direct drive servo motor 3310 cause a
corresponding 360.degree. rotation of valve stem 3335. According to
some embodiments, the valve opening is moved from fully opened to
fully closed in between 7-10 rotations of the valve stem and the
direct drive servo motor is configured to rotate at a speed that
moves the valve opening from fully opened to fully closed in
between 1 and 5 seconds. For example, according to some
embodiments, direct drive servo motor 3310 (which may have the
ability to rotate at up to 6200 RPM according to some embodiments)
is configured to rotate at a maximum of approximately 200 RPM so
that the direct drive servo motor is capable of causing valve
opening 3334 to move from fully opened to fully closed in
approximately 2 seconds. Because a direct drive servo motor will
often have a higher maximum RPM (e.g., 600 RPM, 1200 RPM, 4800 RPM,
6200 RPM, etc.) than the maximum RPM at which the motor will
typically be operated at (e.g., 100 RPM, 200 RPM, 300 RPM, etc.),
using a direct drive servo motor allows a variable-size orifice
valve to be operated slower or faster depending on the specific
requirements of a dispenser, fueling protocol and/or fueling event
(e.g., between 1 and 10 seconds, or longer if desired). Compared to
conventional control valves that can move a valve opening from
fully opened to fully closed on the order of minutes, the ability
of a direct drive servo motor to move a valve opening from fully
opened to fully closed on the order of seconds provides for
significantly faster response times.
[0226] For hydrogen fueling applications, a valve that allows for a
wide range of flow rates is beneficial and, in some cases, may be
required. According to some embodiments, a variable-size orifice
valve (e.g., valve 3330 in flow control valve 3300) has a range
from 0-90 g/min to facilitate control of hydrogen flow for hydrogen
fueling. For example, some exemplary variable-size orifice valves
may be capable of proving 0 g/min at the fully closed position and
90 g/min at the fully opened position. According to some
embodiments, a variable-size orifice valve has a smaller or larger
flow rate range (e.g., 0-40 g/min, 0-60 g/min, 0-80 g/min, 0-100
g/min, 0-120 g/min, etc), as the aspects are not limited to any
particular range provided the range is suitable for hydrogen
fueling. Additionally, the electrical components of the servo motor
may be rated for use in hazardous environments to ensure that the
electrical components operate safely in a hydrogen fueling
environment.
[0227] Having thus described several aspects and embodiments of the
technology set forth in the disclosure, it is to be appreciated
that various alterations, modifications, and improvements will
readily occur to those skilled in the art. Such alterations,
modifications, and improvements are intended to be within the
spirit and scope of the technology described herein. For example,
those of ordinary skill in the art will readily envision a variety
of other means and/or structures for performing the function and/or
obtaining the results and/or one or more of the advantages
described herein, and each of such variations and/or modifications
is deemed to be within the scope of the embodiments described
herein. Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments described herein. It is,
therefore, to be understood that the foregoing embodiments are
presented by way of example only and that, within the scope of the
appended claims and equivalents thereto, inventive embodiments may
be practiced otherwise than as specifically described. In addition,
any combination of two or more features, systems, articles,
materials, kits, and/or methods described herein, if such features,
systems, articles, materials, kits, and/or methods are not mutually
inconsistent, is included within the scope of the present
disclosure.
[0228] The above-described embodiments can be implemented in any of
numerous ways. One or more aspects and embodiments of the present
disclosure involving the performance of processes or methods may
utilize program instructions executable by a device (e.g., a
computer, a processor, controller, or other device) to perform, or
control performance of, the processes or methods. In this respect,
various inventive concepts may be embodied as a computer readable
storage medium (or multiple computer readable storage media) (e.g.,
a computer memory, one or more floppy discs, compact discs, optical
discs, magnetic tapes, flash memories, circuit configurations in
Field Programmable Gate Arrays or other semiconductor devices, or
other tangible computer storage medium) encoded with one or more
programs that, when executed on one or more computers, controllers
or other processors, perform methods that implement one or more of
the various embodiments described above. The computer readable
medium or media can be transportable, such that the program or
programs stored thereon can be loaded onto one or more different
computers or other processors to implement various ones of the
aspects described above. In some embodiments, computer readable
media may be non-transitory media.
[0229] The terms "program" or "software" are used herein in a
generic sense to refer to any type of computer code or set of
computer-executable instructions that can be employed to program a
computer or other processor to implement various aspects as
described above. Additionally, it should be appreciated that
according to one aspect, one or more computer programs that when
executed perform methods of the present disclosure need not reside
on a single computer or processor, but may be distributed in a
modular fashion among a number of different computers or processors
to implement various aspects of the present disclosure.
[0230] Computer-executable instructions may be in many forms, such
as program modules, executed by one or more computers or other
devices. Generally, program modules include routines, programs,
objects, components, data structures, etc. that perform particular
tasks or implement particular abstract data types. Typically the
functionality of the program modules may be combined or distributed
as desired in various embodiments.
[0231] Also, data structures may be stored in computer-readable
media in any suitable form. For simplicity of illustration, data
structures may be shown to have fields that are related through
location in the data structure. Such relationships may likewise be
achieved by assigning storage for the fields with locations in a
computer-readable medium that convey relationship between the
fields. However, any suitable mechanism may be used to establish a
relationship between information in fields of a data structure,
including through the use of pointers, tags or other mechanisms
that establish relationship between data elements.
[0232] When implemented in software, the software code can be
executed on any suitable processor or collection of processors,
whether provided in a single computer or distributed among multiple
computers.
[0233] Further, it should be appreciated that a computer may be
embodied in any of a number of forms, such as a rack-mounted
computer, a desktop computer, a laptop computer, or a tablet
computer, as non-limiting examples. Additionally, a computer may be
embedded in a device not generally regarded as a computer but with
suitable processing capabilities, including a Personal Digital
Assistant (PDA), a smartphone or any other suitable portable or
fixed electronic device.
[0234] Also, a computer may have one or more input and output
devices. These devices can be used, among other things, to present
a user interface. Examples of output devices that can be used to
provide a user interface include printers or display screens for
visual presentation of output and speakers or other sound
generating devices for audible presentation of output. Examples of
input devices that can be used for a user interface include
keyboards, and pointing devices, such as mice, touch pads, and
digitizing tablets. As another example, a computer may receive
input information through speech recognition or in other audible
formats.
[0235] Such computers may be interconnected by one or more networks
in any suitable form, including a local area network or a wide area
network, such as an enterprise network, and intelligent network
(IN) or the Internet. Such networks may be based on any suitable
technology and may operate according to any suitable protocol and
may include wireless networks, wired networks or fiber optic
networks.
[0236] Also, as described, some aspects may be embodied as one or
more methods. The acts performed as part of the method may be
ordered in any suitable way. Accordingly, embodiments may be
constructed in which acts are performed in an order different than
illustrated, which may include performing some acts simultaneously,
even though shown as sequential acts in illustrative
embodiments.
[0237] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0238] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0239] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Multiple elements listed with "and/or" should be construed in the
same fashion, i.e., "one or more" of the elements so conjoined.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can
refer, in one embodiment, to A only (optionally including elements
other than B); in another embodiment, to B only (optionally
including elements other than A); in yet another embodiment, to
both A and B (optionally including other elements); etc.
[0240] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0241] Also, the phraseology and terminology used herein is for the
purpose of description and should not be regarded as limiting. The
use of "including," "comprising," or "having," "containing,"
"involving," and variations thereof herein, is meant to encompass
the items listed thereafter and equivalents thereof as well as
additional items.
[0242] The terms "approximately," "about," and "substantially" may
be used to mean within .+-.20% of a target value in some
embodiments, within .+-.10% of a target value in some embodiments,
within .+-.5% of a target value in some embodiments, and yet within
.+-.2% of a target value in some embodiments. The terms
"approximately," "about," and "substantially" may include the
target value.
[0243] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively.
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