U.S. patent application number 16/091812 was filed with the patent office on 2019-04-25 for transport refrigeration unit with battery boost.
This patent application is currently assigned to Carrier Corporation. The applicant listed for this patent is CARRIER CORPORATION. Invention is credited to Yu H. CHEN, Robert A. CHOPKO, Greg DELDICQUE.
Application Number | 20190120530 16/091812 |
Document ID | / |
Family ID | 58549280 |
Filed Date | 2019-04-25 |
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United States Patent
Application |
20190120530 |
Kind Code |
A1 |
CHOPKO; Robert A. ; et
al. |
April 25, 2019 |
TRANSPORT REFRIGERATION UNIT WITH BATTERY BOOST
Abstract
A transport refrigeration unit (26) includes a compressor (58)
constructed and arranged to compress a refrigerant and an electric
compressor motor configured to drive the compressor. A generator
(54) of the unit is configured to provide electric power to the
compressor motor during standard set point conditions, and an
energy storage device of the unit is configured to supplement the
electric power to the compressor motor during temperature pulldown
conditions.
Inventors: |
CHOPKO; Robert A.;
(Baldwinsville, NY) ; CHEN; Yu H.; (Manlius,
NY) ; DELDICQUE; Greg; (Fayetteville, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CARRIER CORPORATION |
Palm Beach Gardens |
FL |
US |
|
|
Assignee: |
Carrier Corporation
Palm Beach Gardens
CT
|
Family ID: |
58549280 |
Appl. No.: |
16/091812 |
Filed: |
April 4, 2017 |
PCT Filed: |
April 4, 2017 |
PCT NO: |
PCT/US2017/025911 |
371 Date: |
October 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62318602 |
Apr 5, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 27/00 20130101;
F25D 11/003 20130101; F25B 31/02 20130101; F25B 13/00 20130101 |
International
Class: |
F25B 27/00 20060101
F25B027/00; F25B 13/00 20060101 F25B013/00; F25D 11/00 20060101
F25D011/00; F25B 31/02 20060101 F25B031/02 |
Claims
1. A transport refrigeration unit comprising: a compressor
constructed and arranged to compress a refrigerant; an electric
compressor motor configured to drive the compressor; a generator
configured to provide electric power to the compressor motor during
standard set point conditions; and an energy storage device
configured to supplement the electric power to the compressor motor
during temperature pulldown conditions at least one heat exchanger
operatively coupled to the compressor; at least one fan configured
to provide air flow over the at least one heat exchanger; and at
least one electric fan motor configured to drive the at least one
fan, and wherein the generator is configured to provide electric
power to the at least one fan motor during standard set point
conditions.
2-3. (canceled)
4. The transport refrigeration unit set forth in claim 1, wherein
the energy storage device is configured to supplement the electric
power to the at least one fan motor during temperature pulldown
conditions.
5. The transport refrigeration unit set forth in claim 4, wherein
the at least one heat exchanger includes an evaporator heat
exchanger, the at least one fan includes an evaporator fan, and the
at least one electric fan motor includes an evaporator fan
motor.
6. The transport refrigeration unit set forth in claim 5, wherein
the at least one heat exchanger includes a condenser heat
exchanger, the at least one fan includes a condenser fan, and the
at least one electric fan motor includes a condenser fan motor.
7. The transport refrigeration unit set forth in claim 1, wherein
the refrigerant is a natural refrigerant.
8. The transport refrigeration unit set forth in claim 6, wherein
the refrigerant is a natural refrigerant.
9. The transport refrigeration unit set forth in claim 1, wherein
the energy storage device is a battery.
10. The transport refrigeration unit set forth in claim 9, wherein
the battery has a voltage potential with a range of about 48V to
250V.
11. A method of operating a transport refrigeration unit
comprising: utilizing one of an electric generator and an energy
storage device to provide electric power generally during steady
state conditions; and providing supplemental power from the other
of the electric generator and the energy storage device during a
temperature pull down state.
12. The method set forth in claim 11, wherein the energy storage
device is a battery.
13. The method set forth in claim 11, wherein the supplemental
power is provided to a compressor motor.
14. The method set forth in claim 11, wherein the compressor motor
is an alternating current motor and the supplemental power is
delivered through an inverter.
15. The method set forth in claim 14, wherein the electric
generator has a maximum power output that is less than a system
power load during the temperature pull down state.
16. The method set forth in claim 11 further comprising: charging
the energy storage device by the electric generator during part
load operating conditions.
17. The method set forth in claim 11 further comprising: driving
the electric generator by a combustion engine.
18. The method set forth in claim 14, wherein an evaporator fan
motor and a condenser fan motor of the transport refrigeration unit
are direct current motors.
19. The method set forth in claim 11, wherein the electric
generator provides the power to a compressor motor, an evaporator
fan motor and a condenser fan motor during steady state
conditions.
20. The method set forth in claim 11, wherein the energy storage
device provides the power to a compressor motor, an evaporator fan
motor and a condenser fan motor during steady state conditions.
21. A transport refrigeration unit comprising: a compressor
constructed and arranged to compress a refrigerant; an electric
compressor motor configured to drive the compressor; a generator
configured to provide electric power to the compressor motor during
standard set point conditions; and an energy storage device
configured to supplement the electric power to the compressor motor
during temperature pulldown conditions; at least one heat exchanger
operatively coupled to the compressor; at least one fan configured
to provide air flow over the at least one heat exchanger; and at
least one electric fan motor configured to drive the at least one
fan, and wherein the energy storage device is configured to provide
electric power to the at least one fan motor during standard set
point conditions.
Description
BACKGROUND
[0001] The present disclosure relates to transport refrigeration
units and, more particularly, to all-electric transport
refrigeration units.
[0002] Traditional refrigerated cargo trucks or refrigerated
tractor trailers, such as those utilized to transport cargo via
sea, rail, or road, is a truck, trailer or cargo container,
generally defining a cargo compartment, and modified to include a
refrigeration system located at one end of the truck, trailer, or
cargo container. Refrigeration systems typically include a
compressor, a condenser, an expansion valve, and an evaporator
serially connected by refrigerant lines in a closed refrigerant
circuit in accord with known refrigerant vapor compression cycles.
A power unit, such as a combustion engine, drives the compressor of
the refrigeration unit, and may be diesel powered, natural gas
powered, or other type of engine. In many tractor trailer transport
refrigeration systems, the compressor is driven by the engine shaft
either through a belt drive or by a mechanical shaft-to-shaft link.
In other systems, the engine of the refrigeration unit drives a
generator that generates electrical power, which in-turn drives the
compressor.
[0003] With current environmental trends, improvements in transport
refrigeration units are desirable particularly toward aspects of
environmental impact. With environmentally friendly refrigeration
units, improvements in reliability, cost, and weight reduction are
also desirable.
SUMMARY
[0004] A transport refrigeration unit according to one,
non-limiting, embodiment of the present disclosure includes a
compressor constructed and arranged to compress a refrigerant; an
electric compressor motor configured to drive the compressor; a
generator configured to provide electric power to the compressor
motor during standard set point conditions; and an energy storage
device configured to supplement the electric power to the
compressor motor during temperature pulldown conditions.
[0005] Additionally to the foregoing embodiment, the transport
refrigeration unit includes at least one heat exchanger operatively
coupled to the compressor; at least one fan configured to provide
air flow over the at least one heat exchanger; and at least one
electric fan motor configured to drive the at least one fan, and
wherein the generator is configured to provide electric power to
the at least one fan motor during standard set point
conditions.
[0006] In the alternative or additionally thereto, in the foregoing
embodiment, the transport refrigeration unit includes at least one
heat exchanger operatively coupled to the compressor; at least one
fan configured to provide air flow over the at least one heat
exchanger; and at least one electric fan motor configured to drive
the at least one fan, and wherein the energy storage device is
configured to provide electric power to the at least one fan motor
during standard set point conditions.
[0007] In the alternative or additionally thereto, in the foregoing
embodiment, the energy storage device is configured to supplement
the electric power to the at least one fan motor during temperature
pulldown conditions.
[0008] In the alternative or additionally thereto, in the foregoing
embodiment, the at least one heat exchanger includes an evaporator
heat exchanger, the at least one fan includes an evaporator fan,
and the at least one electric fan motor includes an evaporator fan
motor.
[0009] In the alternative or additionally thereto, in the foregoing
embodiment, the at least one heat exchanger includes a condenser
heat exchanger, the at least one fan includes a condenser fan, and
the at least one electric fan motor includes a condenser fan
motor.
[0010] In the alternative or additionally thereto, in the foregoing
embodiment, the refrigerant is a natural refrigerant.
[0011] In the alternative or additionally thereto, in the foregoing
embodiment, the refrigerant is a natural refrigerant.
[0012] In the alternative or additionally thereto, in the foregoing
embodiment, the energy storage device is a battery.
[0013] In the alternative or additionally thereto, in the foregoing
embodiment, the battery has a voltage potential with a range of
about 48V to 250V.
[0014] A method of operating a transport refrigeration unit
according to another, non-limiting, embodiment includes utilizing
one of an electric generator and an energy storage device to
provide electric power generally during steady state conditions;
and providing supplemental power from the other of the electric
generator and the energy storage device during a temperature pull
down state.
[0015] Additionally to the foregoing embodiment, the energy storage
device is a battery.
[0016] In the alternative or additionally thereto, in the foregoing
embodiment, the supplemental power is provided to a compressor
motor.
[0017] In the alternative or additionally thereto, in the foregoing
embodiment, the compressor motor is an alternating current motor
and the supplemental power is delivered through an inverter.
[0018] In the alternative or additionally thereto, in the foregoing
embodiment, the electric generator has a maximum power output that
is less than a system power load during the temperature pull down
state.
[0019] In the alternative or additionally thereto, in the foregoing
embodiment, the method includes charging the energy storage device
by the electric generator during part load operating
conditions.
[0020] In the alternative or additionally thereto, in the foregoing
embodiment, the method includes driving the electric generator by a
combustion engine.
[0021] In the alternative or additionally thereto, in the foregoing
embodiment, an evaporator fan motor and a condenser fan motor of
the transport refrigeration unit are direct current motors.
[0022] In the alternative or additionally thereto, in the foregoing
embodiment, the electric generator provides the power to a
compressor motor, an evaporator fan motor and a condenser fan motor
during steady state conditions.
[0023] In the alternative or additionally thereto, in the foregoing
embodiment, the energy storage device provides the power to a
compressor motor, an evaporator fan motor and a condenser fan motor
during steady state conditions.
[0024] The foregoing features and elements may be combined in
various combinations without exclusivity, unless expressly
indicated otherwise. These features and elements as well as the
operation thereof will become more apparent in light of the
following description and the accompanying drawings. However, it
should be understood that the following description and drawings
are intended to be exemplary in nature and non-limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Various features will become apparent to those skilled in
the art from the following detailed description of the disclosed
non-limiting embodiments. The drawings that accompany the detailed
description can be briefly described as follows:
[0026] FIG. 1 is a perspective view of a tractor trailer system
having a transport refrigeration unit as one, non-limiting,
embodiment of the present disclosure;
[0027] FIG. 2 is a schematic of the transport refrigeration
unit;
[0028] FIG. 3 is an electrical schematic of the transport
refrigeration unit illustrating power loads; and
[0029] FIG. 4 is a flow chart of a method of operating the
transport refrigeration unit.
DETAILED DESCRIPTION
[0030] Referring to FIG. 1, a tractor trailer system 20 of the
present disclosure is illustrated. The tractor trailer system 20
may include a tractor or truck 22, a trailer 24 and a transport
refrigeration unit 26. The tractor 22 may include an operator's
compartment or cab 28 and a combustion engine 42 which is part of
the powertrain or drive system of the tractor 22. The trailer 24
may be coupled to the tractor 22 and is thus pulled or propelled to
desired destinations. The trailer may include a top wall 30, a
bottom wall 32 opposed to and space from the top wall 30, two side
walls 34 space from and opposed to one-another, and opposing front
and rear walls 36, 38 with the front wall 36 being closest to the
tractor 22. The trailer 24 may further include doors (not shown) at
the rear wall 38, or any other wall. The walls 30, 32, 34, 36, 38
together define the boundaries of a cargo compartment 40. It is
contemplated and understood that the cargo compartment may also be
divided into two or more smaller compartments for different
temperature cargo requirements.
[0031] Referring to FIGS. 1 and 2, the trailer 24 is generally
constructed to store a cargo (not shown) in the compartment 40. The
transport refrigeration unit 26 is generally integrated into the
trailer 24 and may be mounted to the front wall 36. The cargo is
maintained at a desired temperature by cooling of the compartment
40 via the transport refrigeration unit 26 that circulates air into
and through the cargo compartment 40 of the trailer 24. It is
further contemplated and understood that the transport
refrigeration unit 26 may be applied to any transport container and
not necessarily those used in tractor trailer systems. Furthermore,
the transport container may be a part of the trailer 24 and
constructed to be removed from a framework and wheels (not shown)
of the trailer 24 for alternative shipping means (e.g., marine,
rail, flight, and others).
[0032] The transport refrigeration unit 26 may be an all-electric
transport refrigeration unit 26, and may include a compressor 58,
an electric compressor motor 60, a condenser heat exchanger 64 that
may be air cooled, a condenser fan assembly 66, a receiver 68, a
filter dryer 70, a heat exchanger 72, a thermostatic expansion
valve 74, an evaporator heat exchanger 76, an evaporator fan
assembly 78, a suction modulation valve 80, and a controller 82
that may include a computer-based processor (e.g., microprocessor).
Operation of the transport refrigeration unit 26 may best be
understood by starting at the compressor 58, where the suction gas
(i.e., natural refrigerant) enters the compressor at a suction port
84 and is compressed to a higher temperature and pressure. The
refrigerant gas is emitted from the compressor 58 at an outlet port
85 and may then flow into tube(s) 86 of the condenser heat
exchanger 64.
[0033] Air flowing across a plurality of condenser coil fins (not
shown) and the tubes 86, cools the gas to its saturation
temperature. The air flow across the condenser heat exchanger 64
may be facilitated by one or more fans 88 of the condenser fan
assembly 66. The condenser fans 88 may be driven by respective
condenser fan motors 90 of the fan assembly 66 that may be
electric.
[0034] By removing latent heat, the gas within the tubes 86
condenses to a high pressure and high temperature liquid and flows
to the receiver 68 that provides storage for excess liquid
refrigerant during low temperature operation. From the receiver 68,
the liquid refrigerant may pass through a subcooler heat exchanger
92 of the condenser heat exchanger 64, through the filter-dryer 70
that keeps the refrigerant clean and dry, then to the heat
exchanger 72 that increases the refrigerant subcooling, and finally
to the thermostatic expansion valve 74.
[0035] As the liquid refrigerant passes through the orifices of the
expansion valve 74, some of the liquid vaporizes into a gas (i.e.,
flash gas). Return air from the refrigerated space (i.e., cargo
compartment 40) flows over the heat transfer surface of the
evaporator heat exchanger 76. As the refrigerant flows through a
plurality of tubes 94 of the evaporator heat exchanger 76, the
remaining liquid refrigerant absorbs heat from the return air, and
in so doing, is vaporized.
[0036] The evaporator fan assembly 78 includes one or more
evaporator fans 96 that may be driven by respective fan motors 98
that may be electric. The air flow across the evaporator heat
exchanger 76 is facilitated by the evaporator fans 96. From the
evaporator heat exchanger 76, the refrigerant, in vapor form, may
then flow through the suction modulation valve 80, and back to the
compressor 58. A thermostatic expansion valve bulb sensor 100 may
be located proximate to an outlet of the evaporator tube 94. The
bulb sensor 100 is intended to control the thermostatic expansion
valve 74, thereby controlling refrigerant superheat at an outlet of
the evaporator tube 94. It is further contemplated and understood
that the above generally describes a single stage vapor compression
system that may be used for natural refrigerants such as propane
and ammonia. Other refrigerant systems may also be applied that use
carbon dioxide (CO2) refrigerant, and that may be a two-stage vapor
compression system.
[0037] A bypass valve (not shown) may facilitate the flash gas of
the refrigerant to bypass the evaporator heat exchanger 76. This
will allow the evaporator coil to be filled with liquid and
completely `wetted` to improve heat transfer efficiency. With CO2
refrigerant, this bypass flash gas may be re-introduced into a
mid-stage of a two-stage compressor.
[0038] The compressor 58 and the compressor motor 60 may be linked
via an interconnecting drive shaft 102. The compressor 58, the
compressor motor 60 and the drive shaft 102 may all be sealed
within a common housing 104. In some embodiments, the compressor
motor 60 may be positioned outside of the compressor housing 104,
and therefore the interconnecting drive shaft 102 may pass through
a shaft seal located in the compressor housing. The compressor 58
may be a single compressor. The single compressor may be a
two-stage compressor, a scroll-type compressor or other compressors
adapted to compress natural refrigerants. The natural refrigerant
may be CO2, propane, ammonia, or any other natural refrigerant that
may include a global-warming potential (GWP) of about one (1).
[0039] Referring to FIG. 2, the transport refrigeration unit 26
further includes a multiple energy source 50 configured to
selectively power the compressor motor 60, the condenser fan motors
90, the evaporator fan motors 98, the controller 82, and other
components 99 (see FIG. 3), which may include various solenoids
and/or sensors. The power may be transferred over various buses
and/or electrical conductors 106. The multiple energy source 50 may
include an energy storage device 52, and a generator 54
mechanically driven by a combustion engine 56 that may be part of,
and dedicated to, the transport refrigeration unit 26. The energy
storage device 52 may be at least one battery or battery bank. In
one embodiment, the energy storage device 52 may be secured to the
underside of the bottom wall 32 of the trailer 24 (see FIG. 1). It
is further contemplated and understood that other examples of the
energy storage device 52 may include fuel cells, and other devices
capable of storing and outputting electric power.
[0040] Referring to FIGS. 2 and 3, power management relative to the
multiple energy source 50 and controlled power distribution
relative to the various power loads may be configured/arranged to
minimize the size of the combustion engine 56 and minimize fossil
fuel consumption while still providing enough electric power to
meet temperature pulldown demands of the operating transport
refrigeration unit 26. The controller 82 through a series of data
and command signals over various pathways 110 may, for example,
control the electric motors 60, 90, 98 as dictated by the cooling
needs of the refrigeration unit 26. The controller 82 may further
control the electric power output of the generator 54 and the
batteries 52 in order to meet the varying load demands of transport
refrigeration unit 26.
[0041] In one example, the generator 54 and the battery or battery
bank 52 may be electrically arranged in series. The electric power
may be generally distributed through the bus 106, and may be direct
current (DC). A converter (not shown) may be arranged at the outlet
of the generator 54. The fan motors 90, 98 may be DC motors, and
the compressor motor 60 may be an alternating current (AC) motor
with an inverter (not shown) at the power input to the motor 60. In
one example, the generator 54 may have a maximum power output of
about 15 kW, the battery bank 52 may output electric power at about
10 kW, the steady state compressor motor 60 load may be about 10
kW, and the evaporator fan motor 98 and condenser fan motor 90 load
may be about 2 kW. It is further contemplated and understood that
various power conditioning devices may be configured throughout the
transport refrigeration unit 26 depending upon the current type and
voltage demands of any particular component.
[0042] In one embodiment, the generator 54 may be configured or
downsized to provide substantially all of the electric power
demands of the transport refrigeration unit 26 including the motors
60, 90, 98 during standard set point conditions (i.e., steady state
conditions). However, when the transport refrigeration unit 26 is
operating in a temperature pulldown state, the batteries 52 are
available as a `battery boost` to increase or supplement the DC
power through the bus 106 thereby satisfying the temporary increase
in power demand of, for example, the compressor motor 60. In this
embodiment, the voltage potential of the batteries 52 may be about
5 kW to 7 kW.
[0043] In another embodiment, the batteries 52 may be configured to
provide substantially all of the electric power demands of the
transport refrigeration unit 26 including the motors 60, 90, 98
during standard set point conditions (i.e., steady state
conditions). However, when the transport refrigeration unit 26 is
operating in a temperature pulldown state, the generator 54 is
available as a `battery boost` to increase or supplement the DC
power through the bus 106 thereby satisfying the temporary increase
or surge in power demand of, for example, the compressor motor 60.
In this embodiment, the voltage potential of the batteries 52 may
be about 15 kW.
[0044] The transport refrigeration unit 26 may further include a
battery charger 108 that may be powered by the generator 54 during
part-load operating conditions of the transport refrigeration unit
26 (i.e., partial compressor load conditions), and controlled by
the controller 82. The battery charger 108 may be controlled by the
controller 82 and is configured to charge the batteries 52 when
needed and during ideal operating conditions. By charging the
batteries 52 during reduced compressor load conditions, the size
and weight of the generator 54 and driving engine 56 may be
minimized.
[0045] Referring to FIG. 4, a method of operating the transport
refrigeration unit 26 may include a first block 200 of driving the
electric generator 54 by the combustion engine 56. In block 202,
the transport refrigeration unit 26 may utilize one of the electric
generator 54 and the energy storage device 52 to provide power to
the compressor motor 60, the evaporator fan motor 98, and the
condenser fan motor 90 during steady state conditions. Per block
204, supplemental power may be provided by the other of the
electric generator 54 and the energy storage device 52 during a
temperature pull down state which may typically require more power
than steady state conditions. In block 206, the energy storage
device 52 may be recharged by the generator 54 during part load
operating conditions of the transport refrigeration unit 26.
[0046] Benefits of the present disclosure when compared to more
traditional transport refrigeration units include lower fuel
consumption, and a refrigeration unit that may emit less noise and
may be lighter in weight. Yet further, the present disclosure
includes an energy storage device that is conveniently and
efficiently recharged to meet the power demands of the
refrigeration unit while meeting combustion engine power and
emission requirements that may be enforced by regulatory/government
agencies.
[0047] While the present disclosure is described with reference to
the figures, it will be understood by those skilled in the art that
various changes may be made and equivalents may be substituted
without departing from the spirit and scope of the present
disclosure. In addition, various modifications may be applied to
adapt the teachings of the present disclosure to particular
situations, applications, and/or materials, without departing from
the essential scope thereof. The present disclosure is thus not
limited to the particular examples disclosed herein, but includes
all embodiments falling within the scope of the appended
claims.
* * * * *