U.S. patent application number 12/849841 was filed with the patent office on 2011-02-10 for heat pump with intgeral solar collector.
This patent application is currently assigned to SOL XORCE LLC. Invention is credited to Michael H. Gurin.
Application Number | 20110030404 12/849841 |
Document ID | / |
Family ID | 43533718 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110030404 |
Kind Code |
A1 |
Gurin; Michael H. |
February 10, 2011 |
HEAT PUMP WITH INTGERAL SOLAR COLLECTOR
Abstract
The present invention generally relates to heat pumps that
utilize at least one thermal source operating with the same working
fluids. In one embodiment, the present invention relates to a
hybrid solar heat pump comprised of at least one microchannel heat
exchanger with integral solar absorber, at least one compression
(i.e., mass flow regulator) device as the heat pump for concurrent
compression to a higher pressure and mass flow regulator of the
working fluid, and at least one working fluid accumulator with the
entire system operating with the same working fluid. The present
invention also generally relates to heat pump systems that utilize
an inventory management system to provide both efficient and safe
operation under a wide range of operating conditions.
Inventors: |
Gurin; Michael H.;
(Glenview, IL) |
Correspondence
Address: |
MICHAEL H. GURIN
4132 COVE LANE, UNIT A
GLENVIEW
IL
60025
US
|
Assignee: |
SOL XORCE LLC
Glenview
IL
|
Family ID: |
43533718 |
Appl. No.: |
12/849841 |
Filed: |
August 4, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61231674 |
Aug 6, 2009 |
|
|
|
61231238 |
Aug 4, 2009 |
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Current U.S.
Class: |
62/235.1 ;
62/324.6; 62/434 |
Current CPC
Class: |
F25B 27/002 20130101;
Y02B 10/20 20130101; Y02A 30/272 20180101; Y02B 10/24 20130101 |
Class at
Publication: |
62/235.1 ;
62/434; 62/324.6 |
International
Class: |
F25B 27/00 20060101
F25B027/00; F25D 17/02 20060101 F25D017/02; F25B 13/00 20060101
F25B013/00 |
Claims
1. A heat pump system comprising one working fluid in at least one
thermodynamic cycle and one mass flow regulator circulating a
working fluid selected from at least one heat transfer fluid of
water, carbon dioxide, and ammonia; both a high-side pressure
circuit downstream of the one mass flow regulator and a low-side
pressure circuit upstream of the one mass flow regulator; and
wherein the one mass flow regulator consumes mechanical or
electrical power of greater than 20 watts.
2. The heat pump system of claim 1 further comprised of a
microchannel solar collector having a microchannel diameter of less
than 2.5 millimeters.
3. The heat pump system of claim 1 wherein the at least one mass
flow regulator increases microchannel solar collector working
fluid.
4. The heat pump system of claim 1 further comprised of at least
two heat exchangers, wherein the at least one mass flow regulator
is operable in a) power generation, b) heating, or c) cooling
mode.
5. The heat pump system of claim 2 wherein the microchannel solar
collector has at least two individually controlled circuits.
6. The heat pump system of claim 2 further comprised of a fluid
accumulator tank and wherein the fluid accumulator tank is between
the at least two individually controlled circuits.
7. The heat pump system of claim 2 wherein the microchannel solar
collector is operable in either solar absorbing or thermal emitting
mode.
8. The heat pump system of claim 1 further comprised of a power
generating expander, a fluid accumulator, a thermodynamic cycle
having a high-side and a low-side pressure with a high-side
pressure having an operating pressure of at least 50 psi greater
than a low-side pressure, wherein the one mass flow regulator is
operable for both increasing the working fluid pressure from the
low-side pressure to the high-side pressure and for removing or
adding working fluid from the thermodynamic cycle into the fluid
accumulator.
9. The heat pump system of claim 1 further comprised of at least
one heat exchanger for independent control of sensible cooling and
at least one heat exchanger for independent control of latent
cooling.
10. The heat pump system of claim 9 wherein the at least one heat
exchanger for independent control of sensible cooling and at least
one heat exchanger for independent control of latent cooling
designed to remove thermal energy from the thermodynamic cycle and
to displace any heat exchangers between the low-side pressure and
high-side pressure.
11. The heat pump system of claim 8 wherein the power generating
expander and the one mass flow regulator are both contained within
a hermetically sealed chamber.
12. The heat pump system of claim 11 wherein the one mass flow
regulator is designed to increase the operating pressure of any
working fluid leaking from the power generating expander.
13. The heat pump system of claim 12 having two overlapping
thermodynamic cycles comprised of a power generating thermodynamic
loop and a heat pump thermodynamic loop, wherein the any working
fluid leaking from the power generating expander is increased to a
pressure at least 5 psi greater than the low-side pressure of the
power generating thermodynamic loop.
14. The heat pump system of claim 11 wherein the power generating
expander is designed to provides all of the generated power in the
form of mechanical shaft power and further designed for the
mechanical shaft power to power the mass flow regulator.
15. The heat pump system of claim 14 further comprised of a back
pressure regulator for the heat pump thermodynamic loop wherein the
back pressure regulator is designed to vary the high-side pressure
of the heat pump thermodynamic loop to consume all of the
mechanical shaft power generated by the power generating
expander.
16. The heat pump system of claim 11 further comprised of an
electric motor wherein the electric motor is designed to generate
mechanical shaft power to operate the one mass flow regulator.
17. The heat pump system of claim 16 further comprised of an
electric motor decoupler designed to either electrically or
magnetically decouple the electric motor or mechanically disconnect
the electric motor from both the one mass flow regulator and the
power generating expander.
18. The heat pump system of claim 16 further comprised of an
electric motor coupled designed to either electrically or
magnetically engage the electric motor or mechanically connected
the electric motor to the one mass flow regulator.
19. The heat pump system of claim 1 further comprised of a fluid
accumulator tank in fluid communication with both high-side
pressure circuit and low-side pressure circuit, wherein the one
mass flow regulator is designed to switch between a mode to remove
working fluid from the high-side pressure circuit into the fluid
accumulator and a mode to add working fluid from the fluid
accumulator into the low-side pressure circuit, and wherein the
fluid communication with the fluid accumulator is designed to be
void of a second mass flow regulator consuming greater than 20
watts of mechanical or electrical power.
20. The heat pump system of claim 19 further comprised of a heat
exchanger in thermal communication with the fluid accumulator tank,
and wherein the working fluid is operable at a working fluid
pressure having a decrease in density per 10 degrees Fahrenheit
increase of at least one percent.
21. The heat pump system of claim 20 wherein the fluid accumulator
is further comprised of at least one fluid inlet port and at least
one fluid discharge port.
22. The heat pump system of claim 21 wherein the at least one fluid
inlet port into the fluid accumulator is in fluid communication
with the high-side pressure circuit and the at least one fluid
discharge port from the fluid accumulator is in fluid communication
with the low-side pressure circuit.
23. The heat pump system of claim 22 wherein the at least one fluid
inlet port is at least one inch higher than the at least one fluid
discharge port.
24. The heat pump system of claim 22 wherein the method of adding
working fluid into the at least one thermodynamic cycle is designed
to have volumetric displacement of working fluid in the fluid
accumulator with working fluid from the high-pressure circuit side
having a density of at least one percent lower than the working
fluid within the fluid accumulator.
25. The heat pump system of claim 24 wherein the method of adding
working fluid into the at least one thermodynamic cycle has an
increased rate of fluid addition of at least 5 percent by
preheating the temperature of the high-pressure circuit side by at
least 10 degrees Fahrenheit greater than the working fluid
temperature within the fluid accumulator.
26. The heat pump system of claim 24 further comprised of solar
collectors downstream of the one mass flow regulator consuming at
least 20 watts of power operable to increase the working fluid
temperature by at least 5 degrees Fahrenheit for adding working
fluid into the at least one thermodynamic cycle.
27. The heat pump system of claim 24 further comprised of solar
collectors downstream of the one mass flow regulator consuming at
least 20 watts of power operable to decrease the working fluid
temperature by at least 5 degrees Fahrenheit for removing working
fluid from the at least one thermodynamic cycle into the fluid
accumulator, wherein the solar collector is operable in a thermal
emitter mode.
28. The heat pump system of claim 24 further comprised of a thermal
source downstream of the one mass flow regulator consuming at least
20 watts of power operable to increase the working fluid
temperature by at least 5 degrees Fahrenheit for adding working
fluid into the at least one thermodynamic cycle.
29. The heat pump system of claim 24 further comprised of at least
one fluid valve control designed to add a circuit containing
working fluid or to decrease the temperature of working fluid
within the high-side circuit pressure and having a thermal sink
downstream of the one mass flow regulator consuming at least 20
watts of power and operable to add working fluid into the at least
one thermodynamic cycle high-side circuit pressure.
30. The heat pump system of claim 24 wherein the method of adding
working fluid into the at least one thermodynamic cycle has an
increased rate of fluid addition of at least 5 percent by cooling
the working fluid temperature within the fluid accumulator by at
least 5 degrees Fahrenheit.
31. The heat pump system of claim 22 wherein the method of removing
working fluid from the at least one thermodynamic cycle is designed
to have volumetric displacement of working fluid in the fluid
accumulator with working fluid from the high-pressure circuit side
having a density of at least one percent greater than the working
fluid within the fluid accumulator.
32. The heat pump system of claim 1 further comprised of two
overlapping thermodynamic cycles with a first thermodynamic cycle
as a power generating thermodynamic loop having a low-side pressure
circuit upstream of a power generating expander and a high-side
pressure circuit downstream of a power generating expander and a
second thermodynamic cycle having a low-side pressure circuit
upstream of the one mass flow regulator and a high-side pressure
circuit downstream of the one mass flow regulator, wherein the
high-side pressure circuit of the second thermodynamic cycle is at
least 5 psi greater than the low-side pressure circuit of the first
thermodynamic cycle.
33. The heat pump system of claim 1 further comprised of a solid
state conversion device including photovoltaic, thermophotovoltaic,
thermoelectric, or thermionic cell having a maximum junction
temperature; and a backpressure regulator designed to modulate the
operating pressure downstream of the one mass flow regulator
wherein the operating pressure maintains a phase change working
fluid temperature within 5 degrees Fahrenheit of the lesser of
solid state conversion device maximum junction temperature or
design temperature.
34. The heat pump system of claim 1 further comprising a second
thermodynamic cycle having a power generating expander in
mechanical communication with the one mass flow regulator
circulating the working fluid, and a combustor having combustor
exhaust, wherein the at least one thermodynamic cycle is the first
thermodynamic cycle and both the first thermodynamic cycle and
second thermodynamic cycle have the same working fluid, wherein the
heat pump system has a coefficient of performance greater than
1.20, and wherein the combustor is at least one thermal source for
the second thermodynamic cycle and the combustor exhaust is at
least one thermal source for the first thermodynamic cycle.
35. The heat pump system of claim 34 further comprising a solar
collector having the same working fluid as both the first
thermodynamic cycle and the second thermodynamic cycle; further
comprising a heat exchanger from a low-pressure circuit side of the
first thermodynamic cycle to a low-pressure circuit side of the
second thermodynamic cycle and wherein the second thermodynamic
cycle is void of any heat exchangers having thermal communication
between a high-pressure circuit side of second thermodynamic cycle
and low-pressure circuit side of second thermodynamic cycle.
36. The heat pump system of claim 35 wherein the working fluid is
carbon dioxide, wherein the high-side circuit pressure of the
second thermodynamic cycle is greater than 2000 psi, the high-side
circuit pressure of the first thermodynamic cycle is greater than
800 psi.
37. The heat pump system of claim 35 wherein the working fluid is
carbon dioxide, wherein the high-side circuit pressure of the
second thermodynamic cycle is greater than 2700 psi, wherein the
high-side circuit pressure of the first thermodynamic cycle is
greater than 1200 psi, wherein the high-side circuit pressure of
the second thermodynamic cycle is greater than 2.2 times the
low-side circuit pressure of the second thermodynamic cycle, and
wherein the high-side circuit pressure of the first thermodynamic
cycle is at least 5 psi greater than the low-side circuit pressure
of the second thermodynamic cycle.
38. The heat pump system of claim 35 further comprised of a heat
exchanger to transfer thermal energy from the second thermodynamic
cycle low-pressure circuit side to a regenerator of a
dehumidification system operable to provide latent cooling, and a
heat exchanger from the first thermodynamic cycle high-pressure
circuit side operable as a condenser and wherein the first
thermodynamic cycle is operable in a cooling mode and the second
thermodynamic cycle is operable as a mechanically interconnected
power source to the at least one mass flow regulator.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Patent
Application Ser. No. 61,231,674 filed Aug. 6, 2009, having the
title "Solar collector with expandable fluid mass management
system" and U.S. Patent Application Ser. No. 61,231,238 filed Aug.
4, 2009, having the title "Heat Pump with Integral Solar Collector"
and included as reference only without priority claims. Numerous
additions have been made since the filing of the provisional patent
applications cited earlier. These include FIGS. 9-14, and FIG. 17.
The combining of the two provisional filings have lead to some of
the original figures being renumbered to maintain like numerals for
like components.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a heat pump
system having a highly integrated mass management system and
external heat source to increase operating efficiency and reduce
capital cost. In all embodiments, the present invention utilizes
the same working fluid within all thermodynamic cycles, and the
present invention utilizes gravity to discharge a relatively cooler
and more dense fluid as displaced by a volumetrically equivalent
relatively warmer and less dense fluid.
BACKGROUND OF THE INVENTION
[0003] Due to a variety of factors including, but not limited to,
global warming issues, fossil fuel availability and environmental
impacts, crude oil price and availability issues, alternative
energy sources are becoming more popular today. One such source of
alternative and/or renewable energy is solar energy. One such way
to collect solar energy is to use a solar receiver to focus and
convert solar energy into a desired form (e.g., thermal energy or
electrical energy). Thermal energy harvested from the sun is known
in the art to be utilized in absorption heat pumps, domestic hot
water and industrial processes, power generating cycles through the
heating of a secondary heat transfer fluid, power generating cycles
through the direct heating of power generating working fluid such
as steam, and for heating. Furthermore, it is recognized that a
wide range of energy consumers can be supplied via electrical
and/or thermal energy such as air conditioning, refrigeration,
heating, industrial processes, and domestic hot water. Given this,
solar collectors that function in efficient manners are
desirable.
[0004] Traditional thermal activated processes effectively consider
every unit of energy into the system. Furthermore by definition
solar energy is a function of solar intensity and thus at the
minimum is absent during the nighttime, unless significant thermal
storage is utilized that is currently very expensive. Additionally,
it recognized in the art that vapor compressor heat pumps have
coefficients of performance "COP" substantially higher than
absorption heat pumps. And hot water heaters utilizing vapor
compressor driven heat pumps also have substantially higher COPs as
compared to direct heating of hot water having COPs less than
unity. In addition, traditional solar collectors, particularly flat
panel collectors, are temperature constrained due in large part to
declining efficiencies as a function of temperature and the
degradation of the working fluid which is often a mixture of a
glycol and water. Solar collectors typically fall into the category
of pump driven working fluid circulation or thermosiphon that
respectively have the deficiency of requiring a pump or orientation
of solar collector with respect to the "condenser".
[0005] Heat pumps also have significant limitations that limit
temperature including the requirement for oil lubrication that
would suffer oxidative destruction at the higher temperatures
desired within heat pumps. Additionally, the working fluid in
virtually all refrigerants is significantly expandable across a
wide operating temperature range.
[0006] The combined limitations of each individual component being
the solar collector and the heat pump presents significant
challenges that are further exasperated when high integration using
the same working fluid for both devices is realized.
[0007] Traditional solar systems utilize a non-expandable working
fluid under pressures less than 50 psia, or working fluids having
expandability ratios between the cold and hot temperatures of less
than 3. The traditional solar systems utilize a working fluid that
is a heat transfer fluid and thus isn't directly compatible as a
thermodynamic cycle working fluid. As noted, the density of the
working fluid by being expandable changes by an order of magnitude
as a function of operating pressure and temperature. Furthermore by
definition solar energy is a function of solar intensity and thus
at the minimum is absent during the nighttime, unless significant
thermal storage is utilized that is currently very expensive, the
system will experience substantial changes in density according to
operating and ambient conditions.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to the use of expandable
fluids for thermally activated processes. The expandable fluid when
heated has decreasing density given the same pressure, and
increasing the pressure creates heat of compression. The heat of
compression is realized in the art through the operation of a heat
pump. The further coupling of heat the expandable fluid using
either solar energy or other externally combusted fuels enables a
significant reduction of capital cost thus lowering the levelized
cost of energy, whether that energy be in the form of thermal or
electricity/mechanical energy. The change in density further
enables one power consuming device, which is a heat pump operable
as a turbocompressor, turbopump, or other configurations of
generally recognized compressors to perform a secondary function of
regulating the inventory of working fluid within the thermodynamic
cycle that the heat pump operates within.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a sequential flow diagram of one embodiment having
multiple configurations of an integrated solar collector and heat
pump in accordance with the present invention;
[0010] FIG. 2 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump having a supplemental
fluid accumulator in accordance with the present invention;
[0011] FIG. 3 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump having multiple thermal
sinks in accordance with the present invention;
[0012] FIG. 4 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump operating as a radiant
cooler in accordance with the present invention;
[0013] FIG. 5 is a sequential flow diagram of one embodiment of an
integrated solar collector switchable as a thermal source or sink,
and heat pump in accordance with the present invention;
[0014] FIG. 6 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump with an integrated
desiccant dehumidifier in accordance with the present
invention;
[0015] FIG. 7 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump with an integrated power
generating expander in accordance with the present invention;
[0016] FIG. 8 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump having multiple thermal
sinks and an integrated photovoltaic cell in accordance with the
present invention;
[0017] FIG. 9 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump configured as a domestic
hot water system in accordance with the present invention;
[0018] FIG. 10 is a sequential flow diagram of one embodiment of an
integrated solar collector with external combustion to superheat
working fluid and heat pump configured as a cooling system in
accordance with the present invention;
[0019] FIG. 11 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump configured with solar
collector as a preheat stage of external combustion stage in
accordance with the present invention;
[0020] FIG. 12 is a sequential flow diagram of one embodiment of an
integrated solar collector and heat pump configured with solar
collector as a superheat stage of external combustion exhaust gases
and heat pump heat of compression stages in accordance with the
present invention;
[0021] FIG. 13 is a sequential flow diagram of one embodiment of an
integrated power generation cycle with a heat pump cycle powered by
power generation cycle configured for cooling in accordance with
the present invention;
[0022] FIG. 14 is a sequential flow diagram of one embodiment of an
integrated power generation cycle with a heat pump cycle powered by
power generation cycle configured for cooling, and a working fluid
inventory management system in accordance with the present
invention;
[0023] FIG. 15 is a sequential flow diagram of one embodiment of an
integrated solar collector and inventory mass management system
operating with a mechanically driven pressure generating device in
accordance with the present invention;
[0024] FIG. 16 is a sequential flow diagram of one embodiment of an
integrated solar collector and inventory mass management system
operating in a hybrid thermosyphon approach in accordance with the
present invention; and
[0025] FIG. 17 is a sequential flow diagram of one embodiment of an
integrated solar collector and inventory mass management system
operating with a series of individually operated fluid circuit
branches in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The term "non-linear", as used herein, includes any surface
of a solar receiver whose surface shape is described by a set of
nonlinear equations.
[0027] The term "microchannel", as used herein, includes channel
dimensions of less than 2.5 millimeters.
[0028] The term "reflector", as used herein, includes a surface or
surface coating that reflects greater than 50% of at least one
portion of the incoming light spectrum, which includes the portions
of visible, infrared, and ultraviolet.
[0029] The term "in thermal continuity" or "thermal communication",
as used herein, includes the direct connection between the heat
source and the heat sink whether or not a thermal interface
material is used.
[0030] The term "multipass", "multi-pass", or "multiple passes", as
used herein, includes a fluid flow into at least one portion of a
heat exchanger and out of at least one other portion of a heat
exchanger wherein the at least one portion of the heat exchanger
and the at least one other portion of a heat exchanger can either
be thermally isolated from each other or in thermal continuity with
each other.
[0031] The term "boiler", as used herein, includes a heat exchanger
transferring thermal energy into a working fluid wherein the
working fluid is comprised of at least 5% vapor phase.
[0032] The term "superheater", as used herein, includes a heat
exchanger transferring thermal energy into a working fluid wherein
the heat exchanger is used to convert saturated steam into dry
steam.
[0033] The term "fluid inlet" or "fluid inlet header", as used
herein, includes the portion of a heat exchanger where the fluid
flows into the heat exchanger.
[0034] The term "fluid discharge", as used herein, includes the
portion of a heat exchanger where the fluid exits the heat
exchanger.
[0035] The term "expandable fluid", as used herein, includes the
all fluids that have a decreasing density at increasing temperature
at a specific pressure of at least a 0.1% decrease in density per
degree C.
[0036] The term "heat transfer fluid" is a liquid medium utilized
to convey thermal energy from one location to another. The terms
heat transfer fluid, working fluid, and expandable fluid are used
interchangeably.
[0037] The present invention generally relates to a solar collect
system having an integral working fluid management system that
enables the system to increase or decrease the mass of the working
fluid within the circulation loop of the closed loop system. The
present invention also generally relates to a heat pump system
having an integral solar collector that utilizes one working fluid
in common between the two elements.
[0038] Here, as well as elsewhere in the specification and claims,
individual numerical values and/or individual range limits can be
combined to form non-disclosed ranges.
[0039] The heat transfer fluid within the embodiments is preferably
a supercritical fluid as a means to reduce the pressure drop within
the heat exchanger. The supercritical fluid includes fluids
selected from the group of organic refrigerants (R134, R245,
pentane, butane), gases (CO2, H2O, He2), The specifically preferred
supercritical fluid is void of hydrogen as a means to virtually
eliminate hydrogen reduction or hydrogen embrittlement on the heat
exchanger coatings or substrate respectively. The particularly
preferred supercritical fluid has a disassociation rate less than
0.5% at the operating temperature in which the heat exchanger
operates. The specifically preferred heat transfer fluid is the
working fluid wherein the combined energy produced (i.e., both
thermal, and electrical) displaces the maximum amount of dollar
value associated with the displaced energy produced within all of
the integrated components including thermodynamic cycle operable
within a power generating cycle, vapor compression cycle, heat pump
cycle, absorption heat pump cycle, or thermochemical heat pump
cycle.
[0040] All of the embodiments can be further comprised of a control
system operable to regulate the mass flow rate of the working fluid
into the solar receiver, with the ability to regulate the mass flow
rate independently for each pass by incorporating a fluid tank
having variable fluid levels optionally interspersed between at
least one pass and the other. One method of control includes a
working fluid inventory management system. The control system
regulates the mass flow rate through methods known in the art
including variable speed pump, variable volume valve, bypass
valves, and fluid accumulators. The control system is further
comprised of at least one temperature sensor for fluid discharge
temperature and at least one temperature sensor for ambient air
temperature or condenser discharge temperature.
[0041] Exemplary embodiments of the present invention will now be
discussed with reference to the attached Figures. Such embodiments
are merely exemplary in nature and not to be construed as limiting
the scope of the present invention in any manner. The depiction of
heat exchangers predominantly as microchannel heat exchangers
having linear porting is merely exemplary in nature and can be
substituted by complex shaped porting of microchannel dimensions or
porting greater than defined by microchannel practice. The
depiction of solar collectors predominantly as flat panel
non-tracking solar absorbers with integral microchannel heat
exchangers is merely exemplary in nature and can be substituted by
tracking collectors of 1 axis or 2 axis type, vacuum evacuated
tubes or panels, switchable configuration between solar absorber or
solar radiator mode, low concentration fixed collector, or high
concentration tracking collectors. The depiction of heat pump as a
vapor compressor device is merely exemplary and can be substituted
with an absorption heat pump. The compressor type can include a
positive displacement device, a gerotor, a ramjet, a screw, and a
scroll. Furthermore, and importantly, the heat pump can be a
turbopump, a positive displacement pump where the selection of the
device to increase the working fluid pressure and operate as a mass
flow regulator is determined by the density at the inlet pressure
and discharge outlet. When the incoming working fluid has a density
greater than 50 kg per m3, or preferably greater than 100 kg per
m3, or specifically greater greater than 300 kg per m3. The
depiction of valves as standard mass flow regulators is merely
exemplary in nature and can be substituted by variable flow
devices, expansion valve, turboexpander, two way or three way
valves. The depiction of methods to remove heat from the working
fluid as a condenser is merely exemplary in nature as a thermal
sink and can be substituted by any device having a temperature
lower than the working fluid temperature including absorption heat
pump desorber/generator, process boilers, process superheater, and
domestic hot water. The depiction of desiccant dehumidifier as
liquid desiccant dehumidifier is merely exemplary and can be
substituted by an adsorption solid desiccant dehumidifier, and high
surface area hydrophilic powders. The depiction of geothermal as
thermal source can be low depth subsurface, moderate depth
geothermal wells, or high depth geothermal sources such as obtained
from oil wells. The depiction of expander as turbine is merely
exemplary as a method to reduce the pressure of the working fluid
enables the generation of mechanical or electrical energy and can
be substituted by turboexpander, positive displacement device, a
gerotor or geroller, a ramjet, screw, or scroll device. The
depiction of photovoltaic cell as single concentration device can
be substituted by thin film, low concentration device, Fresnel
lens, and high concentration devices.
[0042] The control system is further comprised of at least one
temperature sensor for fluid discharge temperature and at least one
temperature sensor for ambient air temperature or condenser
discharge temperature.
[0043] Exemplary embodiments of the present invention will now be
discussed with reference to the attached Figures. Such embodiments
are merely exemplary in nature. Furthermore, it is understand as
known in the art that sensors to measure thermophysical properties
including temperature and pressure are placed throughout the
embodiments as known in the art, most notably positioned to measure
at least one thermophysical parameter for at least one
thermodynamic state point. The depiction of solar collectors
predominantly as flat panel non-tracking solar absorbers with
integral microchannel heat exchangers is merely exemplary in nature
and can be substituted by tracking collectors of 1 axis or 2 axis
type, vacuum evacuated tubes or panels, switchable configuration
between solar absorber or solar radiator mode, low concentration
fixed collector, or high concentration tracking collectors. The
depiction of pump as a vapor compressor device is merely exemplary
and can be substituted with a positive displacement device, a
gerotor, a ramjet, a screw, and a scroll. Furthermore, and
importantly, the pump can be a turbopump, a positive displacement
pump where the selection of the device to increase the working
fluid pressure and operate as a mass flow regulator is determined
by the density at the inlet pressure and discharge outlet when the
incoming working fluid has a density greater than 10-50 kg per m3,
or preferably greater than 100 kg per m3, or specifically greater
greater than 300 kg per m3. The depiction of valves as standard
mass flow regulators is merely exemplary in nature and can be
substituted by variable flow devices, expansion valve,
turboexpander, two way or three way valves. The depiction of
methods to remove heat from the working fluid as a condenser is
merely exemplary in nature as a thermal sink and can be substituted
by any device having a temperature lower than the working fluid
temperature including absorption heat pump desorber/generator,
liquid desiccant dehumidifier, process boilers, process
superheater, and domestic hot water. With regard to FIGS. 1 through
17, like reference numerals refer to like parts.
[0044] The function of the mass management system is to serve as a
means of adding or removing the mass of expandable fluid from the
fluid accumulator into at least one circuit of the solar collector.
Hereinafter, the term "adding fluid" is increasing the mass of
expandable fluid into the fluid accumulator by at least 0.5% on a
weight basis. Hereinafter, the term "removing fluid" is decreasing
the mass of expandable fluid into the fluid accumulator by 0.5% on
a weight basis. It is understood that adding fluid into the fluid
accumulator is removing fluid from the at least one circuit of the
solar collector, hereinafter referred to as "remove fluid from the
solar collector". And removing fluid from the fluid accumulator is
adding fluid into the at least one circuit of the solar collector,
hereinafter referred to as "add fluid into the solar
collector".
[0045] Turning to FIG. 1, FIG. 1 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. The circles containing "A"
and "B" are state point indicators to provide continuity of working
fluid flow between the various alternate scenarios 1 through 4. In
the embodiment of FIG. 1 heat pump solar collector is comprised of
heat pump 10 in fluid communication with a solar collector 20 with
a temperature sensor 32 measuring the discharge temperature of the
working fluid from the heat pump 10. Another temperature sensor 30
measures the discharge temperature of the working fluid as it
leaves the solar collector 20 and prior to the fluid entering the
thermal sink 40 which is in fluid communication with the solar
collector 20. Another temperature sensor 31 measures the discharge
temperature after leaving the thermal sink 40. A pressure sensor 50
measures the discharge pressure from the heat pump 10, though the
actual placement of the pressure sensor 50 can be anywhere
downstream of the heat pump 10 discharge and upstream of a
pressure-reducing device including an expansion valve or
turboexpander. One exemplary method of control is to vary the
discharge pressure of the heat pump 10 such that the temperature of
the working fluid being discharged after the solar collector, which
enables the heat pump energy input to be minimized where the heat
pump 10 concurrently achieves the desired working fluid mass flow
requirement and discharge temperature prior to the solar collector.
The discharge pressure downstream of the heat pump 10 is a function
of the solar flux on the solar collector 20 as a method of
minimizing the operating costs of the heat pump with integral solar
collector as the heat pump requires mechanical and/or electrical
energy. The heat of compression resulting from the heat pump
provides a high coefficient of performance temperature gain (i.e.,
lift) that is subsequently increased further by the solar collector
20. The control system decreases the pressure gain to ensure that
the thermal sink 40 both achieves the required heat transfer and
discharge temperature such that the heat pump, when the solar
collector provides the majority of the heat source into the working
fluid, operates predominantly as a mass flow regulator resulting in
a reduced operating cost of the heat pump. Another advantage of
this embodiment is the elimination of a heat exchanger to transfer
thermal energy captured from the solar collector 20 into the
working fluid, and also eliminating a secondary heat transfer fluid
within the solar collector 20. The preferred working fluid is a
fluid that has virtually no (e.g., less than 1.0% preferred, less
than 0.5% specifically preferred, and less than 0.05% particularly
preferred) thermal degradation resulting particularly from solar
collector stagnation. One exemplary working fluid includes carbon
dioxide, with the particularly preferred embodiment having a heat
pump discharge pressure greater than the supercritical pressure of
carbon dioxide. Additional working fluids include refrigerants,
water, and gases. The particularly preferred embodiment is the
selection of carbon dioxide with a discharge pressure greater than
it's supercritical pressure and the solar collector 20 being a
microchannel device to achieve superior heat transfer with low
pressure drops. Another important design advantage is the selection
of a heat pump 10 device that either operates oil free, thus
eliminating the potential of hydraulic oil from disassociating
(i.e., breaking down) with the solar collector 20. Alternatively
the heat pump can utilize an electrostatic collector to collect any
lubricant utilized within the heat pump, with one exemplary being
ionic liquids. The ionic liquid has the further advantage of having
essentially no vapor pressure in combination of having
electrostatic attraction as a method of limiting the heat pump 10
lubricant from entering the solar collector 20. FIG. 1 shows four
alternative configurations such that "A" is the inlet of the
working fluid into the heat pump 10, and "B" is the discharge of
the working fluid downstream of the thermal sink 40. The first
alternate "alternate 1" depicts an expander 60 downstream of the
thermal sink 40 as a method of recovering at least a portion of the
mechanical/electrical energy expended during in order to obtain the
heat pump compression. This alternate configuration would be
typical for domestic hot water, air conditioning, refrigeration,
industrial processes including processes currently serviced by
traditional combustion powered boilers, furnaces, dryers, etc. The
expander's 60 discharge pressure is regulated by using feedback on
the measured pressure by pressure sensor 50 and discharge
temperature as measured by temperature sensor 33. It is further
anticipated that an external combustor can be downstream of the
solar collector 20 and upstream of the thermal sink 40 as a method
to further increase the working fluid temperature. This
configuration is especially desired for industrial or power
generation processes that involve heating of air (i.e., less dense
than working fluid thus requiring significantly larger heat
exchangers) as a method of superheating the working fluid to the
desired operating temperature of the thermal sink 40. The invention
utilizing the same working fluid for the heat pump as the solar
collector for temperatures exceeding 350C can only be done using a
small set of working fluids most notably ammonia and particularly
preferred carbon dioxide "CO2". Water is another alternative fluid,
though less desirable due to the discontinuous thermophysical
properties as the water transitions to steam. The second alternate
configuration replaces the expander with an expansion valve 90
where the expansion valve as known in the art can operate as a
variable controlled device, open/close switch, and modulated to be
a pulsing device to enhance heat transfer properties. The expansion
valve, which is a special type of fluid control valve 90 enabling
pressure reduction discharge pressure is regulated by using
feedback on the measured pressure by pressure sensor 52 and
discharge temperature as measured by temperature sensor 34. This
configuration, though not as efficient as alternate 1, has a lower
capital cost thus being implemented when the system scale or
financial return on investment doesn't justify the additional
expense of an energy recovery expander 60. The working fluid
downstream of the expansion valve provides cooling through an
evaporator 80 thus operating as an air conditioner, chiller,
refrigerator, or freezer which is dependent on the discharge
temperature as measured by temperature sensor 34. Alternate
configuration 3 simply depicts a closed loop system such that the
heat pump effectively operates as a mass flow regulator, whereby
the pressure gain between the heat pump 10 inlet is a nominal
amount solely to overcome pressure losses associated with the
working fluid passing through the entire circulation loop including
the solar collector 20. Alternate configuration 4 is further
comprised of a fluid accumulator 130 and a control valve 95 as a
method to buffer the inventory of working fluid within the
circulation loop. The fluid accumulator in its simplest form
operates as a temporary storage of working fluid when the operating
pressure within the circulation loop is within 10 psi of the
maximum operating pressure of any individual component. The
invention incorporates a control system to open and close valving
of the alternate 4 configuration, which is preferably configured as
a parallel circuit with any of the prior alternate configurations.
The preferred embodiment has an operating pressure at state point A
of less than the supercritical pressure of the working fluid, which
for CO2 is less than 1000 psi. The particularly preferred
embodiment has a working fluid pressure of less than 800 psi.
Another embodiment is the heat pump cycle operating as a fully
subcritical cycle in which state point A has an operating pressure
of less than 400 psi. The operating pressure at state point B is
preferred to be supercritical, which for CO2 is above 1200 psi as
to ensure low pressure drop throughout the solar collector 20. The
pressure differential across the heat pump 10 is varied such that
the working fluid has a compressibility greater than 10%, which is
dependent on realizing a heat of compression greater than 10
degrees Fahrenheit. The particularly preferred heat of compression
is the greater of 20 degrees Fahrenheit, or such that the
temperature downstream of heat pump 10 is at least 15 degrees
Fahrenheit higher than the ambient air temperature. The preferred
method of control is to operate the low-side pressure of the heat
pump when under Alternate 2 such that the expansion yields a
cooling temperature of at least 2 degrees Fahrenheit cooler than
the air conditioning or refrigeration set point. Under Alternate 2
it is further desirable to maximize the combined thermal heating by
first stage of heat of compression followed by the solar collector,
whereby the solar collector heating varies in real-time as a
function of the thermal sink mass flow rate (i.e., heating domestic
hot water, industrial process heating, etc.) and solar irradiance
flux. The low-side circuit pressure (i.e., upstream of heat pump
10) and pressure ratio under Alternate 1 is selected such that the
mechanical work realized by the expander 60 closely matches the
work input requirement of the heat pump 10 to minimize electricity
requirements.
[0046] Turning to FIG. 2, FIG. 2 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 2
heat pump solar collector the heat pump 10 upstream of the solar
collector 20 is further comprised of a fluid accumulator 130
configured predominantly as an emergency working fluid inventory
storage vehicle where an open/close fluid valve 90 enables a
partial stream of the working fluid, which is now at the higher
pressure as measured by pressure sensor 50 having a temperature as
measured by temperature sensor 31. The working fluid passes through
a condenser 70 in order to increase the density of the working
fluid prior to entering the fluid accumulator 130. The preferred
configuration of the condenser 70 is within the fluid accumulator
130, thus enabling the condenser (effectively a heat exchanger) to
operate as an evaporator/heater. The control system would switch
the condenser from cooling to heating mode once the heat pump
discharge pressure (i.e. working fluid pressure downstream of the
heat pump discharge) becomes at lower than the maximum operating
pressure minus an anti-cycling threshold. The control system would
then subsequently open the valve 90 once the working fluid within
the fluid accumulator 130 exceeds the target set point as measured
by temperature sensor 30.
[0047] Turning to FIG. 3, FIG. 3 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 3
heat pump solar collector depicts one scenario having parallel
circuits and multiple thermal sinks. The heat pump 10, as noted
earlier can operate as mass flow regulator (i.e., booster pump),
more traditional vapor compressor, or more traditional turbopump. A
control system operates the valves as a method of controlling the
mass flow within each parallel circuit. The top circuit is
controlled by valve 90 to enable the working fluid to pass through
the solar collector 20. The invention anticipates the solar
collector 20 operating either as a solar absorber or solar radiator
thus providing the ability to provide "free" heating or cooling
respectively by leveraging the high surface area. The working fluid
downstream of the solar collector 20 transfers thermal energy via a
heat exchanger 80, which can be manufactured using a wide range of
materials (e.g., conductive polymers, aluminum, stainless steel,
etc.) and designed using methods known in the art (e.g.,
microchannel, shell and tube, plate, etc.), into a thermal sink #2
41. The working fluid downstream of the heat exchanger 80 mixes
with working fluid that passes through valve 91, thus effectively
operating as a solar collector bypass valve, and sequentially
passes through a second thermal sink 40 that has a lower target set
point than thermal sink 41. Another thermal sink #3 42 as depicted
removes more thermal energy from the working fluid, though the
working fluid temperature will be at a lower temperature than the
two aforementioned thermal sinks 41 and 40. The last depicted valve
92 enables working fluid to enter the fluid accumulator 130. The
full working features as noted in FIG. 2 are not repeated visually
for the purpose of brevity. A key feature of the heat pump system
is the ability to adapt to changing solar conditions, ambient
weather conditions (e.g., such as changing temperatures and
humidity levels), and changing thermal load requirements (e.g.,
both heating and cooling). Fluid valves 90, 91, and 92 are
optimally variable flow valves enabling the full mass flow rate
achieved by the heat pump 10 to be segmented to meet the individual
heat transfer requirements of thermal sink 40, 41, and 42. As each
fluid valve is modulated the working fluid inventory within the
thermodynamic cycle varies, and thus the inventory management
within the fluid accumulator 130 must modulate fluid valves 92 and
93 to enable fluid to be added and removed from the thermodynamic
cycle high-side and low-side circuits.
[0048] Turning to FIG. 4, FIG. 4 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 4
heat pump solar collector operates as a radiant cooler. A heat pump
10 increases the operating pressure as measured by the pressure
sensor 50 of the working fluid which also has its temperature
increased due to heat of compression as measured by temperature
sensor 30. A secondary heat transfer fluid, such as domestic hot
water is circulated by a pump 160 through a heat exchanger 80 to
remove thermal energy of the working fluid through a thermal sink
40. This serves the purpose of providing the first stage of cooling
prior to reaching the solar collector 20 configured in the radiant
cooling (i.e., thermal emitting as opposed to solar absorbing)
mode. The inlet temperature into the solar collector 20 is measured
by temperature sensor 31 and the discharge temperature is measured
by temperature sensor 32. The solar collector 20 when operating as
a radiant cooler dissipates black body radiation to the sky and
therefore effectively operates as a precooler/subcooler to the
working fluid prior to reaching the expansion valve 91. The now
expanded working fluid provides cooling that absorbs thermal energy
from a thermal source in thermal communication with the evaporator
80. The heat pump 10 inlet pressure and temperature are measured
respectively by pressure sensor 51 and temperature sensor 33. An
alternate configuration for the thermal sink 40 is depicted in
alternate 1 as an air condenser utilizing condenser fans 100
instead of a secondary heat transfer fluid.
[0049] Turning to FIG. 5, FIG. 5 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 5
heat pump solar collector depicts another configuration for
switching the solar collector 20 between a thermal sink 40 and
thermal source mode. In this configuration the solar collector,
which is optionally under vacuum while operating in thermal source
mode, the solar collector has ambient air flowing over the solar
collector 20 surface area. The working fluid then subsequently
passes through the thermal sink 40. Two two-way valves 111 and 110
are depicted here to switch fluid flow direction such that the heat
pump can operate in air conditioning or heating mode, known in the
art as a reversible heat pump. The heat pump 10 has the common
evaporator 80 and expansion valve 91 (alternatively expander) and
condenser (which is depicted as either the thermal sink 40 or solar
collector 20). Configuration 1 depicts the solar collector 20
operating as a radiant cooler. Under such a radiant cooler mode,
the heat pump 10 consumes electricity as provided by either the
electrical grid or off-grid renewable energy. The heat pump
operating parameters such as high-side pressure and low-side
pressure are varied to meet the specific requirements of thermal
sink #1 40 and cooling levels required as realized by evaporator
80. Again, alternate 1 enables the use of condenser fans 100 to
accelerate the removal of heat from the working fluid, where the
thermal sink #1 40 is operable as an air side condenser.
[0050] Turning to FIG. 6, FIG. 6 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 6
heat pump 10 solar collector 20 is depicted further comprising a
liquid desiccant generator 120 and geothermal 140 as a thermal
sink. It is understood that the heat pump with integral solar
collector can operate with either the liquid desiccant generator
120 or the geothermal 140 heat sink, as well as the shown
combination. The heat pump 10 increases the operating pressure of
the working fluid in part by utilizing a controllable two way valve
111 to provide back pressure upstream of the solar collector 20,
while also serving as a mass flow control (i.e., working fluid
pump). The solar collector 20 increases the working fluid
temperature of the portion of the working fluid being transported
through the collector as determined by the control system and
regulated by the amount of fluid bypass again with the two way
valve position 111. The operation in FIG. 6 depicts the heat pump
10 operating as an air conditioning or refrigeration device to
provide the sensible cooling while the liquid desiccant generator
120 provides the latent cooling. The goal is thus to provide
cooling therefore a significant portion of the working fluid is
desired to bypass, whereby regulating fluid diode 700 prevents
backflow into the heat exchanger 80. The solar collector 20 boosts
the working fluid temperature through a heat exchanger 80 as
required to regenerate the liquid desiccant solution. The working
fluid having been transported through the parallel circuit is
combined upstream of the condenser 70 where the working fluid
temperature approaches the ambient temperature. It is understood
that the condenser 70 can be selected from the range of known
condensers including wet, air, evaporative, etc. FIG. 6 also
depicts a working fluid mass management control system though
represented for brevity by a control fluid valve 93 to enable
working fluid to enter or leave the fluid accumulator 130 as noted
in the earlier embodiments. The working fluid can then be
optionally subcooled through a heat exchanger 80 in thermal
communication with a shallow depth (i.e. surface as known in the
geothermal heat pump application, as compared to deep well
geothermal for power generation) geothermal 140 that serves as a
thermal sink upstream of the expansion valve 92. The fluid control
valve 92 operates as an expansion valve to decrease the operating
pressure while enabling rapid cooling of the working fluid that
subsequently absorbs heat through the evaporator 80.
[0051] Turning to FIG. 7, FIG. 7 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 7
heat pump solar collector depicts an integral power generating
cycle with an air conditioning/refrigeration thermodynamic cycle
where both systems operate on the same working fluid. Beginning the
cycle downstream of the heat pump 10, the heat pump 10 increases
the working fluid pressure to the same low side pressure of the
power generating cycle (which is downstream of the valve 91, fluid
diode 700 to prevent backflow and condenser 70). The working fluid
downstream of the heat pump 10 then passes through the condenser 71
to condense the working fluid prior to reaching the pump 160 as a
method of limiting cavitation. The pump 160 subsequently raises the
working fluid, which is now at a significantly higher density, to
the power generating high side pressure. The high pressure working
fluid, which has increased the working fluid temperature by the
heat of compression, now passes through the solar collector 20 to
vaporize and optionally to superheat the fluid as a means of
increasing the enthalpy and thermodynamic efficiency of the power
generating cycle. The now superheated working fluid enters the
expander (e.g., turbine) 150 inlet in order to produce shaft work
(i.e., mechanical energy) that can further be transformed into
electricity or hydraulic energy. As known in the art, the working
fluid enters the condenser 70 in order to reduce the pumping energy
requirements to return the relatively cool working fluid to the
high side pressure. It is understood that the turbine can be any
expander device, as the pump can also include a turbopump or
positive displacement devices. The control system regulates in real
time the mass flow of the working fluid that will further be
expanded in order to match the air conditioning/refrigeration
demands with thermal energy being transferred through the
evaporator 80. It is further understood that the pump 160, heat
pump 10, and expander 150 can operate at partial loads through
means as known in the art. The heat pump 10 can optionally have an
electric motor 1000 with a decoupling mechanism such as a decoupler
1010 to engage or disengage the electric motor. Though depicted
only in FIG. 7, it is understood that the electric motor/generator
1000 and decoupler 1010 can be implemented in all scenarios for
heat pump operation.
[0052] Turning to FIG. 8, FIG. 8 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector in
accordance with the present invention. In the embodiment of FIG. 8
heat pump solar collector depicts a hybrid solar thermal and
photovoltaic configuration. The precise objective of the integrated
heat pump and photovoltaic cell system is to operate with the
control system pressure and temperature control such that the
working fluid transforms from a liquid/supercritical to a
vapor/superheated fluid within the backside of the photovoltaic
cell 200. The operating pressure is dynamically modulated such that
the temperature at state point #2 is less than lesser of the
maximum junction temperature of PV cell 200 or desired operating
temperature. The working fluid subsequently passes through a solar
collector 20 to ensure that the working fluid doesn't create
cavitation in the heat pump 10. The now high pressure working fluid
also at the elevated temperature due to heat of compression is at
sufficiently high temperatures to drive a range of thermal sinks.
These thermal sinks include thermally activated chillers, such as
single, double or triple effect absorption chillers, and adsorption
chillers 230. Subsequently the working fluid passes through thermal
sinks requiring sequentially lower operating temperatures such as
process heat 240 and then domestic hot water 250. The control
system will enable the working fluid to pass through the condenser
70 in the event the working fluid temperature remains higher than
the ambient or wet bulb temperature, which would be obtained by
activating the condenser fans/motors. The working fluid now
transfers thermal energy by absorbing energy through the evaporator
80 and now returning to the backside of the PV cell 200 where
thermal energy is transferred into the working fluid through the
embedded microchannel heat exchanger 210.
[0053] Turning to FIG. 9, FIG. 9 is a sequential flow diagram of
one embodiment of a heat pump with integral solar collector and/or
combustor in accordance with the present invention. In the
embodiment of FIG. 9 heat pump solar collector depicts a hot water
or steam heat pump utilizing the same working fluid within the
entire system.
[0054] The specific implementation is a more efficient alternative
to traditional boilers, as the coefficient of performance "COP" is
greater than 1.0. The particularly preferred COP is greater than
1.20, and the specifically preferred COP is greater than 1.60. The
method of control includes a dynamic control system that ensures
the operating temperature of the working fluid downstream of the
solar collector 20, which is preferably a microchannel heat
exchanger, is less than the maximum working fluid temperature and
also to ensure that the working fluid is a vapor prior to entering
the heat pump 10. The optimal control system has the means to
control the discharge pressure, the mass flow rate, and bypass
valves including a variable fluid valve 91 to preferably a variable
position that modulates the transferring of heat from the working
fluid into the hot water/steam system supply B. Flow points A and B
are utilized to respectively indicate water/steam flow more clearly
where A is relatively cold temperatures as compared to B. Beginning
at the cold water source, two circulating pumps 161 and 162
regulate the mass flow rate into the two respective thermodynamic
cycles with second thermodynamic cycle (i.e., power generation) and
first thermodynamic cycle (i.e., heat pump). Optimally, the
thermodynamic cycle has a high-side and a low-side pressure with a
high-side pressure having an operating pressure of at least 50 psi
greater than a low-side pressure. The one mass flow regulator
(i.e., heat pump 10) is operable for both increase the working
fluid pressure from the low-side pressure to the high-side pressure
and for removing or adding working fluid from the thermodynamic
cycle into the fluid accumulator. The cold water discharged by
circulating pump 161 enters the heat exchanger 802, which is
downstream of the expander 150, thus concurrently operates as a
condenser in the power generation cycle. The power generation cycle
can operate as either a Brayton or Rankine cycle. At ambient
temperatures lower than 65 degrees Fahrenheit, the optimal cycle is
a Rankine cycle with a pressure ratio across the expander 150 of
greater than 2.2, and preferably greater than 2.7. Under ambient
conditions greater than 90 degrees Fahrenheit, a Brayton cycle is
preferred. Continuing the working fluid enters into heat exchanger
803, which is essentially a hybrid regenerator between the second
and first thermodynamic cycles. Heat is transferred from the second
thermodynamic cycle for the purpose of reducing the compressibility
of the working fluid, and thus minimizing compression energy (i.e.,
maximize power generation); while concurrently preheating the
working fluid prior to the heat pump 10, serving as both preheat
and eliminating the potential for cavitation or liquid-lock. The
now relatively warmer working fluid, which is compressible, is
increased to the high-side circuit pressure of the second
thermodynamic cycle by the circulating pump 160 (i.e., turbopump,
turbocompressor, etc.) whereby the working fluid is heated
externally by either or both solar collector 20 and supplemental
combustor 300 of fuel. The now superheated working fluid enters the
expander 150 to produce mechanical shaft power, which is used to
provide required energy to the heat pump 10. The discharge from the
expander remains hot, on the order of100 degrees Celsius below the
discharge temperature from heat exchanger 801, which this now
excess heat is transferred to heat the cold water/steam. The other
path for creating hot water/steam is circulated by circulating pump
162 into the heat exchanger 805, which obtains its thermal energy
from the heat pump 10 heat of compression followed by waste heat
recovery of combustor exhaust 301. The working fluid exiting heat
exchanger 805 is flow regulated by fluid valve 91 operable as an
expansion valve.
[0055] Turning to FIG. 10, which is the reconfiguration of FIG. 9
for producing chilled water or air conditoning instead of hot
water/steam, the thermal sources of solar collector 20 and
combustor 300 are transferred into the working fluid of the second
thermodynamic cycle to maximize power production to drive the
expander 150 via heat exchanger 801. The fundamental difference is
that the combustor exhaust 301 is now used to preheat the working
fluid entering the heat pump 10 to maximize the thermal lift via
heat exchanger 802, with the available thermal energy being
dissipated from the working fluid of the first thermodynamic cycle
through condenser 70 (which can effectively be any heat exchanger
providing heat to a wide range of devices such as absorption
chillers, or industrial process heat). The now "cooled" working
fluid is prepared to go through an expansion valve to provide
cooling.
[0056] Turning to FIG. 11, which is another reconfiguration of FIG.
9, for utilizing harvested solar thermal energy via the solar
collector 20. The preheated working fluid is further heated by
combusting fuel in the combustor 300. The now superheated working
fluid enters the expander 150 to maximize power production.
[0057] Turning to FIG. 12, which is yet another reconfiguration of
FIG. 9, depicts the combustor exhaust gas 301 serving as a second
stage of heating following the heat pump 10 heat of compression.
The heat exchanger 801 recovers the waste heat from exhaust gas,
which particularly under oxyfuel combustion has reduced volume for
enhanced heat transfer with a smaller heat exchanger, and the
configuration of the heat exchanger 801 as known in the art to
withstand corrosives resulting from condensable gas byproducts
(NOx, SOx, etc.). The working fluid is finally superheated by the
solar collector 20 prior to being discharged.
[0058] Turning to FIG. 13, which is yet another reconfiguration of
FIG. 9, but for produced chilled water, air conditioning or
refrigeration. The fundamental advantage of this configuration as
compared to provisional filing and prior art is the absence of a
regenerator, thus all heat transfer out of the second thermodynamic
cycle is at the low-side circuit pressure. Beginning the second
thermodynamic cycle at the discharge of the circulating pump 160
(i.e., turbopump, turbocompressor, etc.), the working fluid then is
heated either directly by flowing through microchannel solar
collectors (i.e., having integral microchannel heat exchanger 801)
or indirectly from combustor 300 through the heat exchanger 801.
The now superheated working fluid enters the expander 150 to
produce mechanical energy to drive directly the heat pump 10. The
now low-pressure working fluid has thermal energy transfer via heat
exchanger 804 to any of a wide range of thermally activated
chillers 230 (e.g., double effect, single effect absorption,
adsorption, etc.). Subsequent thermal energy is transferred to a
desiccant generator 900 via a heat exchanger 802, whereby the
desiccant generator handles the latent load. Any remaining waste
heat from the second thermodynamic power generating cycle is
removed by the condenser 70 in order to minimize circulating pump
160 energy requirements. The first thermodynamic cycle is optimized
for cooling by removing heat of compression through heat exchanger
805 (i.e., operable as a condenser), then pre-cooling through heat
exchanger 806 using ground source geothermal 910, and then using
evaporative cooling 920 via heat exchanger 807. The now pre-cooled
and sub-cooled working fluid is expander through fluid valve 91 to
provide cooling through heat exchanger 803 (i.e., operable as an
evaporator). Alternate 1 simply changes the order of the ground
source geothermal 910 and the evaporative cooler 920. It is
understood that this configuration does not require both geothermal
and evaporative precooling.
[0059] Turning to FIG. 14, a reconfiguration of FIG. 13, integrates
additional flexibility and adaptability to changing conditions.
Beginning with the heat pump 10 heat of compression and preventing
any backflow via fluid diode 700, the working fluid is directed
through the two way valve 110 downstream of the heat pump 10. The
two way valve 110, under conditions suitable for radiant cooling
directs working fluid into solar collector 20 with another
downstream fluid diode 700 again to prevent backflow. Alternatively
under conditions suitable for solar energy harvesting the working
fluid is diverted to the solar collector 20. When sufficient
thermal energy is available from the solar flux the working fluid
is directed to the expander 150 to produce power and again using a
fluid diode 700 to prevent backflow. When conditions do not meet
radiant cooling or solar harvesting, the heat pump 10 operates as a
traditional CO2 based heat pump providing heat of compression. The
now relatively warm working fluid can be utilized for a series of
thermal loads including thermal activated chiller 230, desiccant
generator 900 and domestic hot water 250, all via respectively heat
exchangers 805, 804, and 803. Any remaining waste heat is removed
via the condenser 70. In the event that cooling is required, the
working fluid is directed to heat exchanger 802 in which
evaporative cooling 920 removes additional thermal energy and now
returns back to the heat pump 10 inlet as surrounded by a series of
fluid diodes 700 preventing backflow. The working fluid mass
management system is depicted, where the fluid accumulator 130
obtains working fluid from the high-side circuit pressure and is
removed from the accumulator into the low-pressure circuit side
upstream of the heat pump 10. Alternate 1 simply depicts the heat
pump and expander on the same shaft, such to enable both the heat
pump 10 and expander 150 to be in one hermetically sealed chamber,
thus having an important secondary benefit of increasing the
operating pressure of any working fluid leaking from the power
generating expander 150. The two overlapping thermodynamic cycles
(i.e., power generating thermodynamic loop and a heat pump
thermodynamic loop) has the working fluid leaking from the power
generating expander increased to a pressure of at least 5 psi
greater than the low-side pressure of the power generating
thermodynamic loop.
[0060] Turning to FIG. 15, Removing Fluid from Accumulator (Adding
Fluid into Solar Collector): There are two methods to remove
working fluid from the fluid accumulator 130 with the first being
the use of the solar collector 20 to heat a portion of the working
fluid remaining in the main closed loop system by absorbing solar
flux and transferring this thermal energy via an embedded heat
exchanger within the solar collector 20, and the second being the
use of the condenser 70 as a heat source (as compared to the
traditional role as a heat sink). Utilizing the first method, the
heat pump 10 prevents backflow during normal operation, and the
control system activates the hot inlet valve 93 to the open
position when the solar collector 20 has heated the working fluid
to a target set point temperature (i.e., achieved a specified
density by way of the operating pressure and working fluid
temperature). The discharge fluid valve 93 is subsequently opened
by the control system to enable the relatively low density and
higher temperature working fluid to displace the relatively more
dense and lower temperature working fluid. The method of control
includes the ability to monitor heat pump 10 energy consumption by
methods known in the art including mass flow meter, kilowatt-hour
meter, pump performance maps with a known inlet and discharge
pressure, working fluid inlet temperature, and working fluid
discharge temperature. The control system can also utilize a
database of NIST thermophysical properties to precisely calculate
the amount of working fluid within the fluid accumulator 130, or
within the closed loop system.
[0061] Adding Fluid: The best method of adding fluid, (i.e.,
discharging fluid from the fluid accumulator into the at least one
circuit of the solar collector) centers around the condenser 70 in
thermal communication with heat exchanger 802 operating in reverse
mode as the removing fluid mode, thus as a thermal source instead
of a thermal sink. Under this method, the control system will begin
the process of using a relatively higher temperature and lower
density heat transfer fluid into the embedded heat exchanger of the
fluid accumulator 130 at which point of reaching either or both the
target set point temperature and/or target set point pressure the
cold fluid valve 90 is opened (this assumes that the resulting
pressure within the fluid accumulator is at least temporarily
higher than the closed loop system pressure).
[0062] Turning to FIG. 16, FIG. 16 is a sequential flow diagram of
one embodiment of a solar collector with integral mass management
system in accordance with the present invention. In the embodiment
of FIG. 16 the fluid accumulator discharges directly into the solar
collector preferably operating as a thermosiphon. Beginning with
the working fluid at state point A, at least a portion of the
working fluid passes through the hot inlet valve 93 when the fluid
accumulator is removing working fluid from the main closed loop of
the solar collector thermosiphon system. As with any thermosiphon
system it is critical that the fluid accumulator 130 be located
above the solar collector. The expandable working fluid having
entered the fluid accumulator 130 is cooled through the heat
exchanger 802, which is preferably contained within the fluid
accumulator. The heat transfer fluid utilized to cool the working
fluid is through the accumulator condenser 70. The then
subsequently cooled working fluid within the fluid accumulator 130
is discharged through the discharge valve 93 back into the solar
collector 20, when desired and controlled by a control system to
regulate the combination of mass flow rate of the working fluid and
the operating pressure of the working fluid within the safe margins
of operation. It is understood that temperature sensors can be
placed at each state point, including within the fluid accumulator
to enable the control system to regulate the flow of working fluid,
and heat transfer fluid to remove thermal energy from the working
fluid as a means of heating up a thermal sink including domestic
hot water, industrial processes, heating, and even power
generation. The depiction within FIG. 16, notably the right half of
the drawing shows the utilization of a heat transfer fluid that
ultimately is heated by the solar collector 20 (on the bottom right
side, which is effectively the same as solar collector 20
(graphically and physically above it) but showing the relative
height of each component to each other) whereby the working fluid
removed from the main closed loop transfers a portion of its
thermal energy to increase the density of the stored fluid and is
conserved by subsequent transfer of the thermal energy to increase
from state point T1 33.1 as it passes through valve 90 and the
fluid accumulator condenser 70 via heat exchanger 803, now becoming
state point D having a temperature sensor T2 33.2. This stage
effectively operates as a preheat of the heat transfer fluid, then
passes through the condenser 70 of the main loop now becoming state
point E having a temperature sensor T3 33.3 to continue the flow
through the solar collector 20. The operation of the solar
collector as a thermosiphon requires T1<T2<T3.
[0063] It is anticipated that the removal of working fluid from the
closed loop system into the fluid accumulator 130 can result from
the solar collector operating in essentially a stagnation mode
(thus being a safety precaution to limit the solar collector from
exceeding it's maximum operating pressure specifications), the
closing and/or evacuation of a parallel circuit within the closed
loop system, capturing at least a portion of the working fluid
"charge" within the closed loop system prior to maintenance of the
entire system, enabling the solar collector to operate at
relatively higher ambient temperatures, and/or enabling the solar
collector to operate at relatively lower operating pressure. The
counterpart is the addition of working fluid into the closed loop
system from the fluid accumulator 130 as a result of relatively
lower ambient temperatures, the opening and/or filling of a
parallel circuit within the closed loop system, enabling the solar
collector to operate at relatively lower ambient temperatures,
and/or enabling the solar collector to operate at relatively higher
operating pressure.
[0064] Turning to FIG. 17, the inventory management system with the
central element of fluid accumulator 130 is in thermal
communication with the condenser 70 via the heat exchanger 802.
Fluid is discharged from the fluid accumulator 130 via the
discharge fluid valve 93 into the low-pressure circuit side of the
heat pump 10. Fluid enters the fluid accumulator 130 either
directly through the cold fluid valve 90 or the hot fluid valve 93
respectively when inventory is desired to be increased and
inventory is desired to be decreased in the fluid accumulator 130.
In all cases fluid entering the fluid accumulator 130 is from the
high-pressure circuit side of the heat pump 10. When desiring
relatively hot working fluid, the working fluid is heated either by
the solar collector 20 or the combustor 300. The heat pump system
must adapt quickly when high-side pressure circuits 901 are opened
or closed, as well as low-side pressure circuits 902.
[0065] It is understood in this invention that a combination of
scenarios can be assembled through the use of fluid valves and/or
switches such that any of the alternate configurations can be in
parallel enabling the solar collector to support a wide range of
thermal sinks.
[0066] The power generating expander 150 is designed to provide all
of the generated power in the form of mechanical shaft power and
further designed for the mechanical shaft power to power the mass
flow regulator. The use of the fluid valves 90 serve as a back
pressure regulator for the heat pump thermodynamic loop enabling to
vary the high-side pressure of the heat pump thermodynamic loop to
consume all of the mechanical shaft power generated by the power
generating expander.
[0067] FIG. 7 depicts the use of an electric motor to generate
mechanical shaft power to operate the one mass flow regulator
(i.e., heat pump 10) when insufficient power is available from the
power generating expander 150. The electric motor has a method of
decoupling (i.e., magnetic, physical, or electrical decoupler)
designed to either electrically or magnetically decouple the
electric motor or mechanically disconnect the electric motor from
both the heat pump 10 and the power generating expander 150.
[0068] The fluid accumulator when operating in the thermosiphon
configuration is designed to be void of a second mass flow
regulator consuming greater than 20 watts of mechanical or
electrical power. This is particularly realized when the working
fluid is at a pressure where a decrease in density per 10 degrees
Fahrenheit increase is at least one percent. The configuration of
the fluid accumulator 130 is such that at least one fluid inlet
port is at least one inch higher than the at least one fluid
discharge port. The method of adding working fluid is designed to
have volumetric displacement of working fluid in the fluid
accumulator with working fluid from the high-pressure circuit side
having a density of at least one percent lower than the working
fluid within the fluid accumulator 130. Another method of adding
working fluid with an increased rate of fluid addition by at least
5 percent is by preheating the temperature of the high-pressure
circuit side at least 10 degrees Fahrenheit greater than the
working fluid temperature within the fluid accumulator. Yet another
method of adding working fluid is by using solar collectors 20
downstream of the heat pump 10 to increase the working fluid
temperature by at least 5 degrees Fahrenheit, or to increase the
rate of fluid addition by at least 5 percent through cooling the
working fluid temperature within the fluid accumulator by at least
5 degrees Fahrenheit. While removing working fluid is best done by
decreasing the working fluid temperature by at least 5 degrees
Fahrenheit, or by using volumetric displacement of the working
fluid in the fluid accumulator with working fluid from the
high-pressure circuit side having a density of at least one percent
greater than the working fluid within the fluid accumulator.
[0069] Optimal conditions of the overlapping thermodynamic cycle
has the high-side pressure circuit of the second thermodynamic
cycle at least 5 psi greater than the low-side pressure circuit of
the first thermodynamic cycle.
[0070] Another optimal condition is achieved when the power
generating system has solid state conversion devices including
photovoltaic, thermophotovoltaic, thermoelectric, or thermionic
cell. The high-side pressure is modified to not exceed a maximum
junction temperature using a backpressure regulator. The operating
pressure is selected to maintain a phase change working fluid
temperature within 5 degrees Fahrenheit of the lesser of solid
state conversion device maximum junction temperature or design
temperature.
[0071] The combined power generating and heat pump consuming
efficiency is realized when the second thermodynamic cycle is void
of any heat exchangers having thermal communication between a
high-pressure circuit side of second thermodynamic cycle and
low-pressure circuit side of second thermodynamic cycle.
[0072] The particularly preferred working fluid is carbon dioxide,
with the high-side circuit pressure of the second thermodynamic
cycle greater than 2000 psi, and the high-side circuit pressure of
the first thermodynamic cycle is greater than 800 psi. Another
embodiment is with the high-side circuit pressure of the second
thermodynamic cycle greater than 2700 psi, the high-side circuit
pressure of the first thermodynamic cycle is greater than 1200 psi,
the high-side circuit pressure of the second thermodynamic cycle is
greater than 2.2 times the low-side circuit pressure of the second
thermodynamic cycle, and the high-side circuit pressure of the
first thermodynamic cycle at least 5 psi greater than the low-side
circuit pressure of the second thermodynamic cycle.
[0073] Yet another embodiment is where a heat exchanger is used to
transfer thermal energy from the second thermodynamic cycle
low-pressure circuit side to the regenerator of the
dehumidification (i.e., desiccant generator) to provide latent
cooling, and a heat exchanger from the first thermodynamic cycle
high-pressure circuit side operable as a condenser and wherein the
first thermodynamic cycle is operable in a cooling mode and the
second thermodynamic cycle is operable as a mechanically
interconnected power source to the at least one mass flow
regulator.
[0074] Although the invention has been described in detail with
particular reference to certain embodiments detailed herein, other
embodiments can achieve the same results. Variations and
modifications of the present invention will be obvious to those
skilled in the art and the present invention is intended to cover
in the appended claims all such modifications and equivalents.
* * * * *