Jack JONES & Yi CHAO
Chemisorbent Thermal Change Generator
NASA Demonstrates Novel
Ocean-Powered Underwater Vehicle
ScienceDaily (Apr. 8, 2010) — NASA, U.S. Navy and university
researchers have successfully demonstrated the first robotic
underwater vehicle to be powered entirely by natural,
renewable, ocean thermal energy.
The Sounding Oceanographic Lagrangrian Observer Thermal
RECharging (SOLO-TREC) autonomous underwater vehicle uses a
novel thermal recharging engine powered by the natural
temperature differences found at different ocean depths.
Scalable for use on most robotic oceanographic vehicles, this
technology breakthrough could usher in a new generation of
autonomous underwater vehicles capable of virtually indefinite
ocean monitoring for climate and marine animal studies,
exploration and surveillance.
Researchers at NASA's Jet Propulsion Laboratory, Pasadena,
Calif.; and the Scripps Institution of Oceanography,
University of California, San Diego, completed the first three
months of an ocean endurance test of the prototype vehicle off
the coast of Hawaii in March.
"People have long dreamed of a machine that produces more
energy than it consumes and runs indefinitely," said Jack
Jones, a JPL principal engineer and SOLO-TREC co-principal
investigator. "While not a true perpetual motion machine,
since we actually consume some environmental energy, the
prototype system demonstrated by JPL and its partners can
continuously monitor the ocean without a limit on its lifetime
imposed by energy supply."
"Most of Earth is covered by ocean, yet we know less about the
ocean than we do about the surface of some planets," said Yi
Chao, a JPL principal scientist and SOLO-TREC principal
investigator. "This technology to harvest energy from the
ocean will have huge implications for how we can measure and
monitor the ocean and its influence on climate."
SOLO-TREC draws upon the ocean's thermal energy as it
alternately encounters warm surface water and colder
conditions at depth. Key to its operation are the carefully
selected waxy substances known as phase-change materials that
are contained in 10 external tubes, which house enough
material to allow net power generation. As the float surfaces
and encounters warm temperatures, the material melts and
expands; when it dives and enters cooler waters, the material
solidifies and contracts. The expansion of the wax pressurizes
oil stored inside the float. This oil periodically drives a
hydraulic motor that generates electricity and recharges the
vehicle's batteries. Energy from the rechargeable batteries
powers the float's hydraulic system, which changes the float's
volume (and hence buoyancy), allowing it to move vertically.
So far, SOLO-TREC has completed more than 300 dives from the
ocean surface to a depth of 500 meters (1,640 feet). Its
thermal recharging engine produced about 1.7 watt-hours, or
6,100 joules, of energy per dive, enough electricity to
operate the vehicle's science instruments, GPS receiver,
communications device and buoyancy-control pump.
The SOLO-TREC demonstration culminates five years of research
and technology development by JPL and Scripps and is funded by
the Office of Naval Research. JPL developed the thermal
recharging engine, building on the buoyancy engine developed
for the Slocum glider by Teledyne Webb Research, Falmouth,
Mass. Scripps redesigned the SOLO profiling float and
performed the integration. The 84-kilogram (183-pound)
SOLO-TREC prototype was tested and deployed by the JPL/Scripps
team on Nov. 30, 2009, about 161 kilometers (100 miles)
southwest of Honolulu.
The performance of underwater robotic vehicles has
traditionally been limited by power considerations. "Energy
harvesting from the natural environment opens the door for a
tremendous expansion in the use of autonomous systems for
naval and civilian applications," said Thomas Swean, the
Office of Naval Research program manager for SOLO-TREC. "This
is particularly true for systems that spend most of their time
submerged below the sea surface, where mechanisms for
converting energy are not as readily available. The
JPL/Scripps concept is unique in that its stored energy gets
renewed naturally as the platform traverses ocean thermal
gradients, so, in theory, the system has unlimited range and
endurance. This is a very significant advance."
SOLO-TREC is now in an extended mission. The JPL/Scripps team
plans to operate SOLO-TREC for many more months, if not years.
"The present thermal engine shows the great promise in
harvesting ocean thermal energy," said Russ Davis, a Scripps
oceanographer. "With further engineering refinement, SOLO-TREC
has the potential to augment ocean monitoring currently done
by the 3,200 battery-powered Argo floats." The international
Argo array, supported in part by the National Oceanic and
Atmospheric Administration, measures temperature, salinity and
velocity across the world's ocean. NASA and the U.S. Navy also
plan to apply this thermal recharging technology to the next
generation of submersible vehicles.
To learn more about SOLO-TREC, visit
http://solo-trec.jpl.nasa.gov
.
US2009013691
WO2008140962
PHASE CHANGE MATERIAL THERMAL POWER GENERATOR
Inventor: JONES JACK A [US] ; CHAO YI
Applicant: CALIFORNIA INST OF TECHN [US] ; JONES JACK A
[US] (+2)
EC: F03G7/05 IPC:
F03G7/05; F03G7/00
Abstract -- An energy
producing device, for example a submersible vehicle for
descending or ascending to different depths within water or
ocean, is disclosed. The vehicle comprises a
temperature-responsive material to which a hydraulic fluid is
associated. A pressurized storage compartment stores the fluid
as soon as the temperature-responsive material changes
density. The storage compartment is connected with a hydraulic
motor, and a valve allows fluid passage from the storage
compartment to the hydraulic motor. An energy storage
component, e.g. a battery, is connected with the hydraulic
motor and is charged by the hydraulic motor when the hydraulic
fluid passes through the hydraulic motor. Upon passage in the
hydraulic motor, the fluid is stored in a further storage
compartment and is then sent back to the area of the
temperature-responsive material.
Description
BACKGROUND
[0004] There are many thousands of ocean research buoys that
presently bob up and down in the world's oceans, performing
scientific research on temperature, salinity, global warming,
ocean currents, and pollution. A graph of recent locations of
these battery-powered buoys is shown in FIG. 1. At present,
each buoy, which costs about $25K each, can travel between
sea-level and about 1000 to 2000-m depths, and they are
considered disposable after the batteries wear out, typically
after some months of use.
[0005] There are also many gliding submersibles for the Navy
and for research purposes. Each of these gliding vehicles cost
about $100K, and the batteries last a period of months before
these vessels are also disposed after the batteries run out. A
typical gliding path is shown in FIG. 2 and may cover depths
from sea level to about 700-m.
[0006] For most places in the world's temperate and tropical
oceans, the temperature of the ocean at sea level (typically
15.degree. C. to 30.degree. C.) is significantly warmer than
the ocean below about 500-m depth (typically 4.degree. C. to
7.degree. C.). There is a need to have a floater or glider
that can use the oceans' temperature differences to generate
electricity, thus allowing these submersibles to last a period
of many years, instead of just months.
[0007] U.S. Pat. No. 5,291,847 discloses a submersible system
that uses ocean temperature differences to supply buoyancy
changes. This system uses a phase change material (PCM) that
melts above 10.degree. C. and freezes at temperatures below
10.degree. C. The expansion upon melting causes a liquid to be
compressed and stored, so that it can be released to an
external bladder to create positive buoyancy when desired.
Conversely, when the PCM freezes, it contracts and can accept
fluid from the external bladder to cause the submersible to
sink.
[0008] FIG. 3 (Jack A. Jones and Yi Chao, Novel Thermal
Powered Technology for UUV Persistant Surveillance,
Presentation to the ONR Joint Review of Unmanned Systems
Technology Development, Panama City, Fla., Feb. 10, 2006,
incorporated herein by reference in its entirety) shows an
ocean thermal energy conversion (OTEC) system that uses
hydraulic fluid from a phase change material (PCM) device, so
that when the PCM compresses the liquid, it is stored in a
high pressure bellows inside a pressurized nitrogen chamber.
When electricity is desired, a valve is opened and the fluid
pushes a piston that turns a generator to produce electricity.
[0009] In particular, PCM (10) expands when melted above
10.degree. C., thus forcing out a hydraulic fluid (20) past a
check valve (30). The hydraulic fluid (20) is then stored in a
bellows (40) that is pressurized (e.g., a 200 Bar pressure) by
gas in a chamber (50) external to the bellows (40).
[0010] When valve (60) is open, the hydraulic fluid (20)
passes through and presses against a piston (70) that pushes
geared rack and pinion teeth (80) against another set of gears
(90) which will spin fast due to the gear ratio. A generator
(100) is turned by the last gear in the gear train to produce
power that charges a battery (110). Later, the hydraulic fluid
(20) passes through valve (120) into a fixed volume chamber
(130), thus allowing the piston (70) to return to its original
position. When the PCM is cooled to below 10.degree. C., it
freezes and contracts, thus allowing the hydraulic, fluid to
pass through check valve (140) into the volume (150)
surrounding the PCM tubes (10).
[0011] The device of FIG. 3 proved to be too heavy,
inefficient, complicated and expensive to fabricate.
Commercially available, high-force, rack and pinion gears, as
well as high-pressure pistons, as represented by (70), (80),
(90), and (20) have a very large mass typically of over 15 kg.
Furthermore, the required high ratio gears shown as (80),
(90), and (100) typically have a very low efficiency of 0.5 or
lower. Because the system has so many custom pieces that must
be precisely aligned, it is both complicated and expensive to
fabricate.
SUMMARY
[0012] According to a first aspect, an energy producing device
is disclosed, the device comprising: a temperature-responsive
material adapted to undergo density changes in response to
temperature changes; a hydraulic fluid operatively associated
with the temperature-responsive material, the hydraulic fluid
adapted to be controlled within the energy producing device in
accordance with the density changes of the
temperature-responsive material; a first pressurized storage
compartment configured to store the hydraulic fluid upon the
density change of the temperature-responsive material; a
hydraulic motor fluidically connected with the first
pressurized storage compartment; a first valve adapted to
allow hydraulic fluid passage from the first pressurized
storage compartment to the hydraulic motor; an energy storage
component connected with the hydraulic motor, the energy
storage component being chargeable by the hydraulic motor upon
passage of the hydraulic fluid through the hydraulic motor
thus obtaining conversion of hydraulic energy to electrical
energy; and a second pressurized storage compartment
configured to store the hydraulic fluid after passage of the
hydraulic fluid in the hydraulic motor.
[0013] Further embodiments of the present disclosure are
provide in the written specification, drawings and claims of
the present application.
[0014] The thermal power generator according to the disclosure
may have potential application as an Ocean Thermal Energy
Conversion (OTEC) device. It has quite reasonable efficiencies
compared to other OTEC devices that use the temperature
differences between the upper warm ocean, and cooler deeper
water which is pulled up from below. This might have niche
applications in the commercial electric market for remote
areas.
BRIEF DESCRIPTION OF THE
DRAWINGS
[0015] FIG. 1 shows a
graph of recent locations of battery-powered buoys.
[0016] FIG. 2 shows a
typical gliding path of a submersible.
[0017] FIG. 3 shows a
schematic cross-sectional view of an ocean thermal energy
conversion (OTEC) system that uses hydraulic fluid from a
phase change material.
[0018] FIG. 4 shows a
schematic view of a first embodiment of the system according
to the present disclosure.
[0019] FIG. 5 shows a
schematic view of a second embodiment of the system according
to the present disclosure.
DETAILED DESCRIPTION
[0020] In accordance with the present disclosure, a simplified
system is provided with the use of a hydraulic motor to
replace the piston and a generator to produce electricity.
[0021] As shown in FIG. 4, the PCM (200) melting causes the
hydraulic fluid (210) to be stored in a gas spring bellows
(220) (e.g., at a pressure of 3000 psia) when the fluid is
flowed past valve (230), see path 1. When power is desired,
valve (240) is opened and the fluid passes through a hydraulic
motor (250) (path 2), thus eliminating all the pistons and
gears of FIG. 3 above, and allowing a more simple, efficient
and lightweight operation and charging of battery (255).
[0022] The battery (255) can be used to power scientific
measuring equipment, communications, imaging, etc. It can also
be used for electrically-powered buoyancy control and for
directional control equipment.
[0023] Applicants have noted that a commercially available
hydraulic motor can replace the complicated components
represented by (20), (70), (80), and (90) in FIG. 3. According
to one of the embodiments of the present disclosure, the total
mass for this portion of the system can be reduced from over
15 kg to only about 1 kg, and the total cost can be reduced
from over $30,000 to only about $30, or a factor of about
1000, Furthermore, the mechanical efficiency can be increased
from about 0.5 to about 0.9. A hydraulic gear motor is most
suitable as a lightweight, efficient, and low cost motor, as
shown by (250) in FIG. 4. After the fluid leaves the hydraulic
motor (250), it is stored in a low pressure (e.g. 20 psia)
spring bellows device (260) (sec also path 2), and is
ultimately returned to the PCM vessel (200) when valve (270)
is opened, see path 3. A typical high pressure for chamber
(220) in FIG. 4 is 1000-5000 psi, and a typical low pressure
chamber (260) in FIG. 4 is about 10-200 psi.
[0024] Upon reading of the above description and review of the
embodiment of FIG. 4, the person skilled in the art will
understand that further embodiments can be contemplated with a
different location of the valves shown in FIG. 4 and with a
different number of valves.
[0025] The device shown in FIG. 4 has a higher efficiency and
is much less expensive, and easier to build.
[0026] FIG. 5 shows a further embodiment of the present
disclosure, where both electricity and buoyancy control are
produced if the lower pressure fluid is vented to an external
bladder at depth.
[0027] In particular, as shown in FIG. 5, when the fluid (210)
leaves the hydraulic motor (250), path 2, it is allowed to
pass through valve (280) into an external expandable chamber
or bladder (290) on the submersible, thus causing the
submersible to rise. Since the bladder (250) is external to
the submersible, when it expands, more external water is
displaced. According to Archimedes Principle of Buoyancy, the
submersible will become more buoyant when it displaces for
external water.
[0028] The same valve (280) is later used to move the fluid to
the low pressure (e.g., 10 psia) gas bellows chamber (260)
when descent of the submersible is desired. Ultimately, when
the PCM (200) is cooled, valve (280) is again operated so that
the fluid travels in path 4 back to the chamber (200). This
operation allows the generation of electricity, as well as
direct buoyancy change for the submersible.
[0029] Accordingly, what has been shown is a phase change
material thermal power generator. While this phase change
material thermal power generator has been described by means
of specific embodiments and applications thereof, it is
understood that numerous modifications and variations could be
made thereto by those skilled in the art without departing
from the spirit and scope of the disclosure. It is therefore
to be understood that within the scope of the claims, the
disclosure may be practiced otherwise than as specifically
described herein.
[0030] In particular, the thermal power generator may be
stationary, and be alternately cooled and heated by flowing
water. Furthermore, the thermal power generator may create a
high pressure fluid not by changing phase of a material, but
rather, by virtue of density differences caused in a liquid by
heating.
US5463879
Heat cascading regenerative
sorption heat pump
Inventor: JONES JACK A
Applicant: CALIFORNIA INST OF TECH
Abstract -- A simple heat
cascading regenerative sorption heat pump process with
rejected or waste heat from a higher temperature chemisorption
circuit ("HTCC") powering a lower temperature physisorption
circuit ("LTPC") which provides a 30% total improvement over
simple regenerative physisorption compression heat pumps when
ammonia is both the chemisorbate and physisorbate, and a total
improvement of 50% or more for LTPC having two pressure
stages. The HTCC contains ammonia and a chemisorbent therefor
contained in a plurality of canisters, a
condenser-evaporator-radiator system, and a heater,
operatively connected together. The LTPC contains ammonia and
a physisorbent therefor contained in a plurality of
compressors, a condenser-evaporator-radiator system,
operatively connected together. A closed heat transfer circuit
("CHTC") is provided which contains a flowing heat transfer
liquid ("FHTL") in thermal communication with each canister
and each compressor for cascading heat from the HTCC to the
LTPC. Heat is regenerated within the LTPC by transferring heat
from one compressor to another. In one embodiment the
regeneration is performed by another CHTC containing another
FHTL in thermal communication with each compressor. In another
embodiment the HTCC powers a lower temperature ammonia water
absorption circuit ("LTAWAC") which contains a
generator-absorber system containing the absorbent, and a
condenser-evaporator-radiator system, operatively connected
together. The absorbent is water or an absorbent aqueous
solution. A CHTC is provided which contains a FHTL in thermal
communication with the generator for cascading heat from the
HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by
transferring heat from the generator to the absorber. The
chemical composition of the chemisorbent is different than the
chemical composition of the physisorbent, and the absorbent.
The chemical composition of the FHTL is different than the
chemisorbent, the physisorbent, the absorbent, and ammonia.
BACKGROUND OF THE INVENTION
1. Technical Field
This invention is directed towards regenerative heat pump
system and method using a working fluid or refrigerant and an
adsorbent material.
2. Discussion of the Invention
Heat pumps using solid adsorbent beds are well known as shown
by U.S. Pat. Nos. 4,610,148, 4,637,218 4,694,659, 5,025,635,
5,046,319 and 5,079,928. In general since sorbents take up the
working fluid when cooled and desorb the working fluid when
heated, heat pumps are said to be heat driven. Often in
adsorbent and chemisorbent heat pumps two beds of sorbents are
used, one to adsorb the working fluid while the other bed is
desorbing the working fluid. Alternate heating and cooling of
the beds is the conventional procedure. When used in air
conditioning, heat from an interior room may be used to
evaporate the working fluid in an evaporator with heat
rejection to the environment at ambient temperatures.
In all of such systems the efficiency of the apparatus is
measured by its coefficient of performance or "COP". By the
term "COP" as used herein is meant the ratio of heating or
cooling work performed divided by the amount of power required
to do the work. Since cooling COP.sub.S, or COP.sub.CS, are
generally lower than heating COP.sub.S, or COP.sub.HS, many
systems are rated on their cooling COP.sub.S.
U.S. Pat. No. 4,637,218 mentions cooling COP.sub.S between 1
and 2 and heating COP.sub.S between 2 and 3. In U.S. Pat. No.
4,637,218 a hot coolant is pumped from a hot 204.4.degree. C.
sorbent compressor to a cooler 37.8.degree. C. sorbent
compressor, while at the same time cold coolant is pumped from
the cooler sorbent compressor to the hotter sorbent
compressor. Both compressors exchange heat yielding a typical
heat regeneration efficiency of about 80%. The remainder of
the heat is supplied by a boiler at about 204.degree. C.
U.S. Pat. No. 4,610,148 reports a theoretical heating COP of
about 3 and a cooling COP of about 2, and, a calculated
operating COP.sub.H of about 2.6 and a calculated operating
COP.sub.C of about 1.6.
FIG. 3 of U.S. Pat. No. 4,694,659, which is concerned with a
dual sorbent bed heat pump, shows heating and cooling COP's as
a function of a dimensionless thermal wavelength parameter.
Cryogenic cooler systems for sorption refrigerators using a
sorption compressor, a heating/cooling loop and a
Joule-Thomson expansion valve, or "J-T" valve, with methane as
a refrigerant gas and charcoal as the adsorbent, are disclosed
in articles entitled "High Efficiency sorption Refrigerator
Design", and, "Design and Component Test Performance of an
Efficient 4 W, 130 K Sorption Refrigerator" in Advances In
Cryogenic Engineering, Vol. 35, Plenum Press, New York, 1990.
Desorption occurs at 4.46 MPa (646 psia), i.e. P.sub.H, and
adsorption at 0.15 MPa (22 psia), i.e. P.sub.L, or a pressure
ratio of about 30, i.e. P.sub.H /P.sub.L =30. Methane is
expanded from 4.46 MPa to 0.15 MPa to achieve cooling below
130.degree. K. (-143.degree. C.). The sorbent is heated from
240.degree. K. (-33.degree. C.) to 600.degree. K. (327.degree.
C.) to desorb the methane.
U.S. Pat. Nos. 4,875,346 and 5,157,938 disclose cryogenic
refrigeration systems in which heat is transferred by helium
heat transfer gas from a higher temperature circuit to a lower
temperature circuit. When heat is to be transferred, helium is
charged to annular gas-gaps between concentric higher and
lower temperature circuits. The helium heat transfer fluid is
not recycled in a closed loop bt exhausted to a vacuum such as
outer space leaving a vacuum in the gas-gaps when no heat is
to be transferred between circuits. The working fluids used in
the system are xenon, krypton and oxygen.
U.S. Pat. No. 4,732,008 uses heat from a high condenser and
high absorber of a higher temperature solution pair to heat a
low generator of a lower temperature solution pair.
U.S. Pat. No. 4,827,728 uses a heat exchanger for heating the
generator of the absorption circuit with heat rejected from
the condenser and absorber of a medium absorption circuit.
U.S. Pat. Nos. 5,025,635 and 5,079,928 transfer heat with a
heat transfer fluid from one chemisorbent to another
chemisorbent, e.g. from MgBr.sub.2 to CoBr.sub.2 to CoCl.sub.2
to CaBr to SrBr.sub.2.
U.S. Pat. No. 5,042,259 discloses a regenerative hydride heat
pump system for regenerating the sensible heat of the system
which involves a series of at least four canisters containing
a lower temperature performing hydride and a series of at
least four canisters containing a higher temperature
performing hydride. Each canister contains a heat conductive
passageway through which a heat transfer fluid is circulated
so that sensible heat is regenerated.
Gas Research Institute Report No GRI-88/0273 of October 1988,
entitled Solid-Vapor Adsorption Refrigeration System
Development, discusses solid-vapor inorganic complex compounds
such as hydrates and amines and cycles for use in industrial
refrigeration applications. Vapor pressure plots of compounds
CC260-1260 and CC260-1300, which are solid inorganic complex
compounds and are useful adsorbents for use in this invention,
are found on pages 23 and 29 of Report No. GRI-88/0273.
U.S. Department of Energy, Paper No. DE91 010442, entitled
Development of a High-Efficiency, Gas-Fired, Absorption Heat
Pump for Residential and Small-Commercial Applications,
September 1990, by Phillips Engineering Co. discusses the
generator-absorber heat-exchange (GAX) cycle using
ammonia-water as the fluid pair; and FIG. 14 thereof is a
schematic flow diagram of the GAX absorption unit.
Chemisorbents useful for the higher temperature circuit of
this invention are set forth in U.S. Pat. Nos. 4,848,994,
5,025,635 and 5,079,928.
A two staged adsorption system is disclosed in an article
entitled "Improving Adsorption Cryocoolers By Multi-stage
Compression And Reducing Void Volume", Cryogenics, 1986, Vol
26, page 456, by S. Bard. Refrigerant is passed between carbon
adsorbent stages. However, a circuit for the heat transfer
fluid for regenerating heat was not shown. It is understood
that the heat was simply exhausted and not regenerated.
U.S. Pat. No. 5,025,635 discloses staged adsorbers each
containing different adsorbents, i.e. MgBr.sub.2, CoBr.sub.2,
CoCl.sub.2, CaBr.sub.2 and SrBr.sub.2 in a single housing
U.S. Pat. No. 5,079,928 mentions that some reactors in a
staged system can be combined into a single reactor.
Regenerative heat transfer fluid circuits for a single stage
system are disclosed in U.S. Pat. No. 5,046,319.
Other references of interest are U.S. Pat. Nos. 4,732,008,
4,827,728 and 4,848,994, and an article entitled "Sorption
Cooler Technology Development At JPL", Cryogenics, 1990, Vol
30, page 239, by J. A. Jones.
SUMMARY OF THE INVENTION
The following terms are used herein. By the term
"chemisorbent" as used herein is meant chemical absorbent. By
the term "chemisorption" as used herein is meant chemical
absorption. By the term "physisorbent" as used herein is meant
physical absorbent or physical adsorbent. By the term
"physisorption" as used herein is meant physical absorption or
physical adsorption. The term "canister" is used for the
reactor containing the chemisorbent. The term "compressor" is
used for the reactor containing the physisorbent or physical
adsorbent.
Accordingly, there is provided by the principles of this
invention a heat cascading regenerative sorption heat pump
process with waste or rejected heat from a higher temperature
chemisorption circuit powering a lower temperature physical
adsorption circuit. The process comprises providing a higher
temperature ammonia chemisorption circuit containing ammonia
and a chemisorbent having a first chemical composition
operable for chemisorbing and desorbing ammonia. The ammonia
chemisorption circuit comprises a plurality of canisters each
containing the chemisorbent, first condensing means, first
evaporating means for cooling a low temperature load, first
heating means for heating the chemisorbent to a first upper
temperature for desorption of ammonia, and first cooling means
for cooling the chemisorbent, operatively connected together.
Each canister has a heat transfer element in thermal
communication with, but not in fluid communication with, the
chemisorbent therein.
The process further comprises providing a lower temperature
ammonia physical adsorption circuit containing ammonia and a
physical adsorbent having a second chemical composition
operable for physically adsorbing and desorbing ammonia, the
second chemical composition being different than the first
chemical composition. The ammonia physical adsorption circuit
comprises adsorption/desorption means containing the physical
adsorbent and having a first part for desorbing ammonia and a
second part for adsorbing ammonia, second condensing means,
second evaporating means for cooling a low temperature load,
second heating means for heating the physical adsorbent in the
first part of the adsorption/desorption means to a second
upper temperature for desorption of ammonia, and second
cooling means for rejecting heat therefrom, operatively
connected together.
The process also comprises providing at least one first closed
heat transfer circuit containing a first heat transfer liquid
which is different than the chemisorbent, the physical
adsorbent and ammonia. The first closed heat transfer circuit
comprising the heat transfer element of at least one canister,
and heat exchange means in thermal communication with the
first part of the adsorption/desorption means but not in fluid
communication with the physical adsorbent.
In the process, cooling the chemisorbent by the first cooling
means is by flowing the first heat transfer liquid through the
heat transfer element of the at least one canister thereby
cooling it and the chemisorbent therein. In this process,
heating the first part of the adsorption/desorption means and
the physical adsorbent therein by the second heating means to
a second upper temperature for desorption of ammonia is by
flowing the first heat transfer liquid from the at least one
canister through the heat exchange means thereby heating the
first part, and thereby cascading heat from the higher
temperature ammonia chemisorption circuit to the lower
temperature ammonia physical adsorption circuit. The process
further includes regenerating heat within the
adsorption/desorption means by transferring heat from the
first part thereof to the second part thereof.
In one embodiment, the first heating means for heating the
chemisorbent to a first upper temperature for desorption of
ammonia provides the entire net heat added to the process.
In another embodiment, rejecting heat from the lower
temperature ammonia physical adsorption circuit is by
transferring heat from the second part of the
adsorption/desorption means to a third low temperature heat
sink, thereby cooling the second part.
In one embodiment the chemisorbent is selected from the group
consisting of MgCl.sub.2, CaBr.sub.2, SrBr.sub.2, CoBr.sub.2,
and solid inorganic ammoniated complex compounds. In another
embodiment, the chemisorbent is a solid inorganic complex
compound selected from the group consisting of alkaline earth
metal chlorides, bromides and chlorate salts, metal chlorides,
bromides and chlorate salts in which the metal is Cr, Mn, Fe,
Co, Ni, Ca, Ta or Re, a double chloride salt selected from
NH.sub.4 AlCl.sub.4, NaAlCl.sub.4, (NH.sub.4).sub.2
ZnCl.sub.4, (NH.sub.4).sub.3 ZnCl.sub.5, K.sub.2 ZnCl.sub.4,
CsCuCl.sub.3, and K.sub.2 FeCl.sub.5, and NaBr and NH.sub.4
Cl. Non-limiting examples of some useful ammoniated complex
compounds, the limits of the ligand and temperature ranges are
given in U.S. Pat. No. 4,848,994, which is hereby incorporated
herein by reference.
In another embodiment, the physical adsorbent is selected from
the group consisting of activated carbon, zeolite, alumina and
silica gel.
In one embodiment heating the at least one canister to the
first upper temperature comprises heating it directly with the
first heating means.
In another embodiment, the heating the at least one canister
to the first upper temperature comprises heating the flowing
first heat transfer liquid with the first heating means
thereby producing a heated flowing first heat transfer liquid,
and flowing the heated first heat transfer liquid to the at
least one canister, and transferring heat from the heated
flowing first heat transfer liquid to the at least one
canister.
In one embodiment, the first low temperature heat load is an
interior space in a structure, and the second low temperature
heat load is also an interior space in the structure.
In one embodiment, the process further comprising regenerating
heat within the higher temperature chemisorption circuit by
transferring heat from at least one hotter temperature
canister to at least one cooler temperature canister.
In another embodiment, the process further comprising, after
the flowing first heat transfer liquid has transferred heat to
the first part of the adsorption/desorption means,
regenerating heat within the higher temperature chemisorption
circuit by transferring heat from the flowing first heat
transfer liquid to at least another one of the canisters.
In one embodiment, the first condensing means is also the
second condensing means, the first evaporating means is also
the second evaporating means, and the first low temperature
heat load is also the second low temperature heat load.
In one embodiment, the second upper temperature is lower than
the first lower temperature. In another embodiment, the second
upper temperature is higher than the first lower temperature.
In one embodiment, after flowing the first heat transfer
liquid to the heat exchange means of the first part of the
adsorption/desorption means, the process further comprises
flowing the first heat transfer liquid through the heat
transfer element of at least one other canister.
In one embodiment, the third low temperature heat sink is the
ambient environment.
In another embodiment, the adsorption/desorption means is a
plurality of physical adsorption compressors each containing
the physical adsorbent, and the process comprises heating at
least one compressor to a second upper temperature and
desorbing ammonia from the physical adsorbent therein. In this
embodiment, the heat exchange means is in thermal
communication with the at least one compressor and the process
further comprises heating the at least one compressor to the
second upper temperature by transferring heat from the flowing
first heat transfer liquid to the heat exchange means, and
transferring heat from the heat exchange means to the at least
one compressor, thereby cascading heat from the higher
temperature ammonia chemisorption circuit to the lower
temperature ammonia physical adsorption circuit. In a further
embodiment, regenerating heat within the physical adsorption
circuit is by transferring heat from the at least one
compressor to the at least one other compressor; and cooling
at least one compressor by transferring heat therefrom to a
third low temperature heat sink.
In one embodiment, after flowing the first heat transfer
liquid to the heat exchange means of the at least one
compressor, the process further comprises flowing the first
heat transfer liquid through the heat transfer element of at
least one other canister.
In another embodiment, the process further comprising
providing a second closed heat transfer circuit containing a
second heat transfer liquid, the second closed heat transfer
circuit comprising a heat transfer element in thermal
communication with each compressor but not in fluid
communication with the physical adsorbent. A further
embodiment comprises regenerating heat within the physical
adsorption circuit by flowing the second heat transfer liquid
through the heat transfer element of each compressor and
transferring heat between the flowing second heat transfer
liquid and the heat transfer elements. In another further
embodiment, transferring heat from the heat exchange means to
the at least one compressor comprises transferring heat from
the heat exchange means to the flowing second heat transfer
liquid, and then transferring heat from the flowing second
heat transfer liquid to the heat transfer element of the at
least one compressor.
In one embodiment, the process further comprises directing the
flowing second heat transfer liquid to and from the heat
transfer elements of the compressors in a predetermined order
so that the flowing second heat transfer liquid exiting from
the third heat sink flows first to the heat transfer element
of the compressor operating at the second lower temperature,
then in series to the heat transfer elements of the other
compressors, and then back to the third heat sink.
In another embodiment, the process further comprises
activating and deactivating the first heating means in a
predetermined order, directing the flowing first heat transfer
liquid to and from the canisters in a predetermined order,
directing the flowing second heat transfer liquid to and from
the heat transfer elements of the compressors in a
predetermined order, and sequentially advancing the
predetermined order of compressors being heated to the second
upper temperature. In a further embodiment, directing the
flowing first heat transfer liquid to and from the canisters
in a predetermined order is such that the flowing first heat
transfer liquid exiting from a canister cooling from the first
upper temperature transfers heat indirectly to a compressor
operating at the second upper temperature. In another
embodiment, directing the flowing first heat transfer liquid
to and from the canisters in a predetermined order is such
that the flowing first heat transfer liquid exiting from a
canister operating at the first lower temperature transfers
heat indirectly to a compressor operating at the second upper
temperature.
Further examples of control of regenerative adsorption heat
pump processes are described in U.S. Pat. No. 5,046,319 and
U.S. patent application Ser. No. 07/855,642 filed Apr. 30,
1992, which are hereby incorporated herein by reference.
Further examples of control of chemisorbent heat pump
processes are described in U.S. Pat. No. 5,042,259 which is
hereby incorporated herein by reference.
In one embodiment, the number of the at least one first closed
heat transfer circuit is equal to the number of the canisters.
In another embodiment, the number of the at least one first
closed heat transfer circuit is two. In one embodiment,
wherein the number of the at least one first closed heat
transfer circuit is two, the process further comprises
performing heating of the at least one canister to the first
upper temperature in one of the closed first heat transfer
circuits, and performing heating the at least one compressor
to the second upper temperature in the other one of the closed
first heat transfer circuits.
In one embodiment, the process further comprises providing a
second closed heat transfer circuit containing a flowing
second heat transfer liquid, the second closed heat transfer
circuit having a heat transfer element in thermal
communication with each compressor but not in fluid
communication with the physical adsorbent, and the heat
exchange means comprises a plurality of heat exchangers, the
number of heat exchangers being equal to the number of
compressors, and further comprising pairing a heat exchanger
with each compressor. In this embodiment transferring heat
from the flowing first heat transfer liquid to the heat
exchange means comprises directing the flowing first heat
transfer liquid from the canister cascading heat to the lower
temperature ammonia chemisorption circuit, to the heat
exchanger paired with the compressor receiving cascading heat
from the higher temperature ammonia physical adsorption
circuit, and directing the flowing second heat transfer liquid
to the heat exchanger paired with the compressor receiving
cascading heat thereby producing a heated flowing second heat
transfer liquid, and thereafter flowing the heated second heat
transfer liquid to the heat transfer element of the compressor
receiving cascading heat.
In a further embodiment, the process includes controlling the
second upper temperature during desorption of the physical
adsorbent in each compressor so that the pressure in the
compressor during such desorption is equal to pressure in the
canisters during desorption of the chemisorbent in the
canisters.
In one embodiment of this invention the heat cascading
regenerative sorption heat pump process further comprises
providing each canister with a heat transfer element in
thermal communication with the chemisorbent therein but not in
fluid communication with the chemisorbent, and providing each
compressor with a heat transfer element in thermal
communication with the physical adsorbent therein but not in
fluid communication with the physical adsorbent. In this
embodiment the process includes providing a plurality of heat
exchangers, the number of which are equal to the number of the
compressors. Each heat exchanger has a first section in
thermal communication with the a second section. The process
includes pairing a heat exchanger with each compressor. The
process further comprises providing a plurality of first
closed heat transfer circuits each containing a first heat
transfer liquid, the number of the first closed heat transfer
circuits being equal to the number of the canisters. Each
first closed heat transfer circuit comprises the heat transfer
element of one canister, the first section of at least one of
the heat exchangers, and pumping means for flowing the first
heat transfer liquid therein. The process also includes
providing a second closed heat transfer circuit containing a
second heat transfer liquid. The second closed heat transfer
circuit comprises the heat transfer elements of the
compressors, the second sections of the heat exchangers, and
pumping means for flowing the second heat transfer liquid
therein. The process includes flowing the first heat transfer
liquid through the heat transfer element of at least one
canister, and then to the first section of one heat exchanger.
Heating the at least one compressor to the second upper
temperature comprises transferring heat from the flowing first
heat transfer liquid in the first section to the flowing
second heat transfer liquid in the second section, and
transferring heat from the flowing second heat transfer liquid
to the heat transfer element of the compressor being heated to
the second upper temperature. The process also includes
regenerating heat within the physical adsorption circuit by
flowing the second heat transfer liquid from the heat transfer
element of the hottest compressor to the heat transfer element
of another compressor, thereby transferring heat from the
physical adsorbent in one compressor to the physical adsorbent
in another compressor. The process further includes cooling
the second heat transfer liquid by transferring heat therefrom
to a third low temperature heat sink and flowing the cooled
second heat transfer liquid to one of the compressors thereby
cooling it.
In one embodiment the heat transfer fluid is selected from the
group consisting of mixtures of diphenyl and diphenyl oxide,
ortho-dichlorobenzene, ethylene glycol, methoxypropanol,
silicon oils, and water. Examples of such heat transfer fluids
are the Dowtherm.TM. fluids.
In another embodiment, the compressors have two pressure
stages with a lower stage operating over a low to intermediate
pressure range and a higher stage operating over an
intermediate to high pressure range. In a further embodiment,
the low temperature heat load being cooled by the process is a
refrigerator and freezer combination.
Further examples of staged regenerative sorption heat pump
processes are described in my patent application Ser. No.
8/113,611, filed AUG. 27, 1993, which is hereby incorporated
herein by reference.
There is also provided by the principles of this invention a
heat cascading regenerative sorption heat pump process with
rejected heat from a higher temperature chemisorption circuit
powering a lower temperature water absorption circuit. The
process comprises providing a higher temperature ammonia
chemisorption circuit containing ammonia and a chemisorbent,
the chemisorbent having a first chemical composition operable
for chemisorbing and desorbing ammonia. All of the higher
temperature ammonia chemisorption circuit described above with
the lower temperature physical adsorption circuit can also be
used in this embodiment.
The process further comprises providing a lower temperature
ammonia water absorption circuit containing ammonia and an
absorbent selected from the group consisting of water and
absorbent aqueous solutions operable for absorbing and
desorbing ammonia. The absorbent having a second chemical
composition operable for physically absorbing and desorbing
ammonia, the second chemical composition being different than
the first chemical composition. The lower temperature ammonia
water absorption circuit comprises absorption/desorption means
containing the absorbent and having a first part for desorbing
ammonia and a second part for absorbing ammonia, second
condensing means, second evaporating means for cooling a low
temperature load, second heating means for heating the first
part of the absorption/desorption means and the absorbent
therein to a second upper temperature for desorption of
ammonia, and second cooling means for rejecting heat
therefrom, operatively connected together.
The process also comprises providing at least one first closed
heat transfer circuit containing a first heat transfer liquid,
the first heat transfer liquid being different than the
chemisorbent, the absorbent and ammonia, the first closed heat
transfer circuit comprising the heat transfer element of at
least one canister, and heat exchange means in thermal
communication with the first part of the absorption/desorption
means but not in fluid communication with the absorbent.
In the process cooling the chemisorbent by the first cooling
means is by flowing the first heat transfer liquid through the
heat transfer element of the at least one canister thereby
cooling it and the chemisorbent therein. In this process,
heating the first part of the absorption/desorption means and
the absorbent therein by the second heating means to a second
upper temperature for desorption of ammonia is by flowing the
first heat transfer liquid from the at least one canister
through the heat exchange means thereby heating the first
part, and thereby cascading heat from the higher temperature
ammonia chemisorption circuit to the lower temperature ammonia
water absorption circuit. The process further includes
regenerating heat within the absorption/desorption means by
transferring heat from the first part thereof to the second
part thereof.
In one embodiment, the first heating means for heating the
chemisorbent to a first upper temperature for desorption of
ammonia provides the entire net heat added to the process.
In another embodiment, rejecting heat from the lower
temperature ammonia water absorption circuit is by
transferring heat from the second part of the
absorption/desorption means to a third low temperature heat
sink, thereby cooling the second part.
In one embodiment, the chemisorbent is selected from the group
consisting of MgCl.sub.2, CaBr.sub.2, SrBr.sub.2, CoBr.sub.2,
and solid inorganic ammoniated complex compounds.
In another embodiment, the absorbent for the lower temperature
circuit is water.
In one embodiment, the first part of the absorption/desorption
means is a generator for separating a strong aqueous ammonia
solution into a gaseous ammonia stream and a weak aqueous
ammonia solution stream, and the second part of the
absorption/desorption means is an absorber for absorbing a
gaseous ammonia stream in the weak aqueous ammonia solution
stream. In a further embodiment, the ammonia water absorption
circuit containing ammonia is an AHE circuit, and in another
embodiment it is an GAX circuit.
In another embodiment, the second upper temperature is lower
than the first lower temperature.
In one embodiment the heat transfer fluid is selected from the
group consisting of mixtures of diphenyl and diphenyl oxide,
ortho-dichlorobenzene, ethylene glycol, methoxypropanol,
silicon oils, and water. Examples of such heat transfer fluids
are the Dowtherm.RTM. fluids.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and a
physisorption circuit of this invention.
FIG. 2 is schematic flow diagram of the heat
transfer circuit of FIG. 1 with a separate working fluid
circuit for the chemisorption side and a physisorption side.
FIG. 3 is schematic flow diagram of FIG. 1 with
designated points of temperature to be used with the
discussion of Table 1.
FIG. 4 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and a
physisorption circuit of another embodiment of this
invention.
FIG. 5 is schematic flow diagram of a single
working fluid circuit for the chemisorption side and a
physisorption side for use with the heat transfer circuit of
FIGS. 1 and 4.
FIG. 6 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and a two stage
physisorption circuit of still another embodiment of this
invention.
FIG. 7 is schematic flow diagram of a single
working fluid circuit for a two stage physisorption side for
use with the heat transfer circuit of FIG. 6.
FIG. 8 is schematic flow diagram of another
embodiment of this invention having two separate working
fluid circuits for a two stage physisorption circuit for use
with the heat transfer circuit of FIG. 6.
FIG. 9 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and a
physisorption circuit of yet another embodiment of this
invention.
FIG. 10 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and a liquid
absorption circuit of an embodiment of this invention.
FIG. 11 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit with heat
regeneration during the chemisorption cycle and a liquid
absorption circuit of an embodiment of this invention.
FIG. 12 is schematic flow diagram of the heat
transfer circuit of a chemisorption circuit and liquid
absorption circuit of another embodiment of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the drawings, like
characters are employed to designate like parts. With
particular reference first to FIG. 1, a schematic flow diagram
is shown, generally designated by numeral 20, of the heat
transfer fluid circuit of one embodiment of this invention for
a heat cascading regenerative sorption heat pump system. In
this embodiment waste heat from a higher temperature ammonia
chemisorption circuit 22 is used to power a lower temperature
ammonia physisorption circuit 23.
As shown in FIG. 1, the higher temperature chemisorption heat
transfer fluid circuit 22 comprises two canisters 24A and 24B,
check valves 25A, 25B, 25C and 25D, manifolds 27 and 28, the
chemisorption sides of heat exchangers 29A, 29B, 29C and 29D,
solenoid valves 30A, 30B, 30C and 30D (i.e. valve set 30), and
external heat source 32.
Chemisorption canisters 24A and 24B, contain heat transfer
elements 33A and 33B, respectively, surrounded by
chemisorbents 34A and 34B for ammonia. One end of heat
transfer element 33A is connected to lines containing check
valves 25A and 25B, which are connected to the inlet of
manifold 27, and the outlet of manifold 28, respectively. One
end of heat transfer element 33B is connected to lines
containing check valves 25C and 25D, which are connected to
the inlet of manifold 27 and the outlet of manifold 28,
respectively. The outlets of manifold 27 are connected to the
chemisorption side of heat exchangers 29A, 29B, 29C and 29D,
which are connected to solenoid valves 30A, 30B, 30C and 30D,
respectively, which are connected to inlets of manifold 28.
The other ends of heat transfer elements 33A and 33B are
connected to reversible pump 35, by lines 37A and 37B. A first
heat transfer fluid is pumped through heat transfer elements
33A and 33B, and the chemisorption side of heat exchanger 29A,
29B 29C and 29D by pump 35.
External heat source 32 comprises vessel 38 containing bath
heat transfer medium 39 and heating unit 40. Heating unit 40
heats bath medium 39 which in turn heats the first heat
transfer fluid as it is being pumped through lines 37A and
37B. Heating means 40 can be gas or oil heat or any other heat
source desired.
The lower temperature physisorption heat transfer fluid
circuit 23 comprises pump 42, manifold 43, solenoid valves 44A
44B, 44C and 44D (i.e. valve set 44), the physisorption side
of heat exchangers 29A, 29B, 29C and 29D physisorption
compressors 45A, 45B, 45C and 45D, check valves 46A, 46B, 46C
and 46D, solenoid valves 47A 47B, 47C and 47D (i.e. valve set
47), manifold 48 and radiator 51.
Physisorption compressors 45A 45B, 45C and 45D, contain heat
transfer elements 49A, 49B, 49C and 49D respectively,
surrounded by physisorbent 50A, 50B, 50C and 50D, respectively
for ammonia.
The outlet of pump 42 is connected to the inlet of manifold
43. The outlets of manifold 43 are connected to solenoid
valves 44A, 44B, 44C and 44D, which are connected to the
physisorption side of heat exchangers 29A, 29B, 29C and 29D,
respectively, which are connected to one of the ends of heat
transfer elements 49A, 49B, 49C and 49D, respectively. The
other ends of heat transfer elements 49A, 49B, 49C and 49D are
connected to lines containing check valves 46A, 46B, 46C and
46D, and also to lines containing solenoid valves 47A, 47B,
47C and 47D. Solenoid valves 47A, 47B, 47C and 47D are
connected to the inlets of manifold 48. The outlet of manifold
48 is connected to radiator 51 which is connected to the inlet
of pump 42.
The outlet of check valves 46A, 46B, 46C and 46D are also
connected to the physisorption side of heat exchangers 29A,
29B, 29C and 29D, respectively.
A second heat transfer fluid is pumped through the
physisorption side of heat exchangers 29A, 29B, 29C and 29D,
heat transfer elements 49A, 49B, 49C and 49D, and radiator 51,
by pump 42.
Heat from the first heat transfer fluid in higher temperature
chemisorption side of heat exchangers 29A, 29B, 29C and 29D
heats the second heat transfer fluid as it is being pumped in
counter-current flow through the physisorption side thereof,
which in turn heats the physisorption compressors 45A, 45B,
45C and 45D.
Briefly stated, and understood by one skilled in the art, in
operation, heated heat transfer fluid is directed by pump 35
to one of heat transfer elements 33A and 33B, then through one
of heat exchangers 29A, 29B, 29C and 29D as a result a
corresponding one of solenoid valves 30A, 30B, 30C and 30D
being open while the remaining valves of valve set 30 are
closed, and then through the remaining heat transfer elements.
In a similar manner, another heated heat transfer fluid flows
through one of heat exchangers 29A, 29B, 29C and 29D, as a
result one of solenoid valves 44A, 44B, 44C and 44D being open
while the remaining valves of valve set 44 are closed, then
through a corresponding one of heat transfer elements 49A,
49B, 49C and 49D, and then serially through the remaining heat
transfer elements as a result of one of solenoid valves 47A,
47B, 47C and 47D being open while the remaining valves of
valve set 47 are closed, before flowing through radiator 51
and back to pump 42. Radiator 51 rejects heat to a low
temperature heat sink such as the environment, as indicated by
arrow 52.
For example, if valve 30A is open, valves 44D and 47D will
also be open and all other solenoid valves closed thereby
causing, in series order from pump 42, to compressor 45C which
is the coolest, to compressor 45B which is being cooled, to
compressor 45A which is the hottest, to compressor 45D which
is being heated, and then to radiator 51.
Referring to FIG. 1, solenoid valves 30A, 30B, 30C, 30D, 44A,
44B, 44C and 44D, 47A, 47B, 47C and 47D, are controlled by
controller means 41 so that only one of valve set 30, only one
of valve set 44, and only one of valve set 47, are open for a
predetermined period of time during the base part and extended
or bottoming part of each phase. Controller means 41 also
controls reversible pump 35 so that the heat transfer fluid
pumped therein flows in a first direction for a predetermined
period of time, stops pumping for a predetermined period of
time, or pumps in a reverse direction for a predetermined
period of time. Controller means 41 further prevents heat
cascading during the extended or bottoming part of any phase
by stopping pump 35, and pumping the heat transfer fluid
directly from pump 42 to a predetermined compressor and
therefrom directly to radiator 51. Controller means 41 also
controls external heating unit 40 so that heating of heat
transfer medium 39 occurs only as need to maintain its
temperature to a predetermined value.
A schematic flow diagram for the working fluid or ammonia
circuits that are used in conjunction with the heat transfer
circuit of FIG. 1, is shown in FIG. 2, comprises higher
temperature chemisorbent ammonia circuit 55 and lower
temperature physisorbent ammonia circuit 56. Ammonia circuit
55 comprises chemisorbents 24A and 24B, check valves 58A and
58B, condenser 59, Joule-Thomson expansion means 60,
evaporator means 62 containing a charge of liquid ammonia 61,
check valves 63A and 63B, and preferably vapor regenerators
64A and 64B, and auxiliary heat exchanger 65. Briefly stated,
and understood by one skilled in the art, in operation
desorbed high temperature, high pressure ammonia from one of
canisters 24A and 24B, flows through vapor regenerators 64A
and 64B, through check valves 58A and 58B to condenser 59.
Heat is rejected from condenser 59 to a low temperature heat
sink such as the environment, as indicated by arrow 53, and
the liquid ammonia is condensed to form a low temperature,
high pressure liquid. The ammonia liquid is further cooled in
auxiliary heat exchanger 65 and then expanded through
Joule-Thomson valve 60 to form a low temperature, low pressure
liquid, which is collected in evaporator means 62. A low
temperature heat load, as indicated by arrow 54, vaporizes the
liquid ammonia 61 to form a low temperature, low pressure
ammonia gas. The low temperature, low pressure ammonia gas
flows through one of check valves 63A and 63B into one of
canisters 24A and 24B.
Similarly ammonia circuit 56 comprises physisorbents 50A, 50B,
50C and 50D, check valves 66A, 66B, 66C and 66D, condenser 67,
Joule-Thomson expansion means 68, evaporator means 69
containing a charge of liquid ammonia 71, check valves 70A,
70B, 70C and 70D, and preferably vapor regenerators 72A, 72B,
72C and 72D, and auxiliary heat exchanger 73. Briefly stated,
and understood by one skilled in the art, in operation
desorbed high temperature, high pressure ammonia from one or
more but not all of compressors 45A, 45B, 45C and 45D, flows
through vapor regenerators 72A, 72B, 72C and 72D, through
check valves 66A, 66B, 66C and 66D to condenser 67 whereupon
heat is rejected from condenser 67 to a low temperature heat
sink such as the environment, as indicated by arrow 74, and
the gaseous ammonia is condensed to form a low temperature,
high pressure liquid. The ammonia liquid is further cooled in
auxiliary heat exchanger 73 and then expanded through
Joule-Thomson valve 68 to form a low temperature, low pressure
liquid, which is collected in evaporator means 69. A low
temperature heat load, as indicated by arrow 75, vaporizes the
liquid ammonia 61 to form a low temperature, low pressure
ammonia gas. The low temperature, low pressure ammonia gas
flows through one or more but not all of check valves 70A,
70B, 70C and 70D into compressors 45A, 45B, 45C and 45D.
In all the circuits described herein the check valves open and
close automatically whenever the pressure on the upstream side
of the valve is greater than the pressure on the downstream
side of the valve.
With regard to the system shown in FIG. 2, estimated
temperatures at various times during the cycle are listed in
Table 1 along with indicated flow direction of the heat
transfer fluid through reversible pump 38, the opened solenoid
valve in each of valve sets 30, 44, and 47, and comment on the
canisters and compressors conditions. The location of
temperature points T1 to T7 are shown on FIG. 3. Points T1,
T2, T3 and T4 are fixed, while points TS, T8 and T7 are
located proximate the compressor corresponding to the opened
solenoid valve of valve set 30. For example, if valve 30C is
open, temperatures T5-T7 refer to the temperature of points
proximate to compressor 45C. In this particular embodiment,
referring to FIGS. 1 and 2, it is assumed that the bath heat
transfer medium is maintained at 225.degree. C., radiator 51
cools the heat transfer fluid to 40.degree. C., chemisorbents
34A and 34B are MgCl.sub.2 and the canister pressure range is
from 5 to 15 bar, physisorbents 50A-D are carbon and the
compressor pressure range is also from 5 to 15 bar, and the
working fluid for both the higher and lower temperature
circuits is ammonia. As can be seen from Table 1, for this
embodiment, the maximum temperature reached in the
physisorption compressors is between the maximum and minimum
operating temperatures of the chemisorption canisters.
FIG. 4 is a schematic flow diagram of another embodiment of
the heat transfer fluid circuits of this invention in which
solenoid valve sets 30, 44 and 47 of FIG. 2 are replaced with
four-way solenoid valves 76, 77 and 78, respectively. If
desired, check valves 25A-D can be replaced with multiple-way
solenoid valve 79. Controller means 86 controls valves 76, 77
and 78 so that only one of the four inlet or outlet passages
of each valve is in fluid communication with lines 76L, 77L
and 78L, respectively. Controller means 86 further controls
valve 79 so that heat transfer element 33A is in fluid
communication with only one of lines 76L or 79L at a time, and
heat transfer element 33B is in fluid communication with the
other one of lines 76L or 79L at the same time. Controller
means 86 opens the valves 76, 77, 78 and 79 for a
predetermined period of time. Controller means 86 also
controls reversible pump 35 so that the heat transfer fluid
pumped therein flows in a first direction for a predetermined
period of time, stops pumping for a predetermined period of
time, or pumps in a reverse direction for a predetermined
period of time. Controller means 86 further prevents heat
cascading during the extended or bottoming part of any phase
by stopping pump 35, and pumping the heat transfer fluid
directly from pump 42 to a predetermined compressor and
therefrom directly to radiator 51. Controller means 86 also
controls external heating unit 40 so that heating of heat
transfer medium 39 occurs only as need to maintain its
temperature to a predetermined valve. Other than as mentioned
above the operation of the system of FIG. 4 is similar to that
described for FIGS. 1 to 3. Higher and lower temperature
ammonia working fluid circuits 55 and 56 of FIG. 2 can also be
used with the heat transfer fluid circuits of FIG. 4.
When the systems FIGS. 1 to 4 are operated, with
ammonia-MgCl.sub.2 as the working fluid-chemisorbent pair,
with desorption at 220.degree. C. and 15 bar, with adsorption
at 180.degree. C. and 5 bar, the chemisorbent system has a
COP.sub.C of about 0.3; and with ammonia-carbon as the working
fluid-physisorbent pair, with desorption at 175.degree. C. and
15 bar, and with adsorption at 40.degree. C. and 5 bar, the
physisorbent system has a COP.sub.C of about 1.0; with a
combined COP.sub.C of about 1.3.
FIG. 5 is another embodiment of the ammonia working fluid
circuit of this invention, generally designated by numeral 80,
in which higher temperature chemisorption circuit 22 and lower
temperature physisorption circuit 23 share the same condenser
59, Joule-Thomson valve 60, evaporator means 62, ammonia
source 61 and auxiliary heat exchanger 65. If desired, circuit
80 can be used as the ammonia circuit for the heat transfer
circuits of FIGS. 1 and 4.
FIG. 6 is yet another embodiment of this invention, in which
single stage compressors 45A-D of FIG.8 are replaced with two
stage physisorption compressors 82A, 82B, 82C and 82D having
first stage carbon physisorbents 83A, 83B, 83C and 83D, and
second stage carbon physisorbents 84A, 84B, 84C and 84D,
respectively, separated by non-permeable partition 85A, 85B,
85C and 85D, respectively. The operation of the heat transfer
circuit of FIG. 6 is the same as that described for FIGS. 1, 3
and 4. The operation of the ammonia working fluid circuit for
the higher temperature chemisorption circuit can be the same
as that described and shown for circuit 55 of FIG. 2, however,
the operation of the ammonia working fluid circuit for the
lower temperature physisorption circuit is not the same as
that described and shown for circuit 56 of FIG. 2 but rather
is illustrated in FIG. 7.
FIG. 7, shows a schematic flow diagram for the ammonia circuit
of a two stage compression regenerative heat pump process,
generally designated by numeral 81. For ease of illustration,
only the ammonia working fluid circuit for the lower
temperature physisorption circuit is shown in FIG. 7. As can
be seen the circuit has four first stage compression zones
containing carbon physisorbents 83A, 83B, 83C and 83D, and
four second stage compression zones containing carbon
physisorbents 84A, 84B, 84C and 84D.
A quantity of ammonia 71, as the working fluid, contained in
evaporator 69 is vaporized at a low pressure and conveyed
through line 87. Line 87 is in heat transfer communication
with line 94 in auxiliary heat exchanger 73. Line 87, which is
connected to the inlet of manifold 89, the outlets of which
are connected to first stage inlet check valves 90A, 90B, 90C
and 90D, which are connected to vapor regenerators 91A, 91B,
91C and 91D, respectively, which are in fluid communication
with first stage compression zone carbon physisorbent 83A,
83B, 83C and 83D, respectively.
First stage compression zone carbon physisorbents 83A, 83B,
83C and 83D, and second stage compression zone carbon
physisorbents 84A, 84B, 84C and 84D, respectively, are
separated by partitions 85A, 85B, 85C and 85D, respectively,
and housed in compressors 82A, 82B, 82C and 82D, respectively.
Each partition prevents direct fluid communication between the
first stage and second stage compression zones within the
compressor.
Vapor regenerators 91A, 91B, 91C and 91D are also connected to
first stage outlet check valves 92A, 92B, 92C and 92D,
respectively, which are connected to the inlets of manifold
93, the outlet of which is connected to the inlet of manifold
95, the outlets of which are connected to second stage inlet
check valves 96A, 96B, 96C and 96D, which are connected to
vapor regenerators 97A, 97B, 97C and 97D, respectively, which
are in fluid communication with second stage compression zone
carbon physisorbents 84A, 84B, 84C and 84D, respectively.
Vapor regenerators 97A, 97B, 97C and 97D are also connected to
second stage outlet check valves 98A, 98B, 98C and 98D,
respectively, which are connected to the inlets of manifold
99, the outlet of which is connected to condenser 67, which is
connected to line 94. Line 94 is connected to expansion valve
68, which is connected to evaporator 69, thereby forming a
closed ammonia working fluid loop. Solenoid valves 76, 77, 78
and 79, pump 35 and external heat source 40 are controlled by
controller 86 in the same manner as described for FIG. 4.
When the system of FIGS. 6 and 7 is operated, with
ammonia-MgC1.sub.2 as the working fluid-chemisorbent pair,
with desorption at 220.degree. C. and 15 bar, with adsorption
at 180.degree. C. and 5 bar, the chemisorbent system has a
COP.sub.C of about 0.3; and with ammonia-carbon as the working
fluid-physisorbent pair in both physisorption stages, with
desorption at 175.degree. C. and 15 bar in the second stage,
and with adsorption at 40.degree. C. and 5 bar in the first
stage, the physisorbent system has a COP.sub.C of about 1.2;
with a combined COP.sub.C of about 1.5.
FIG. 7 shows only the ammonia physisorption circuit. The
ammonia chemisorption circuit to be used with FIG. 7 is not
shown in FIG. 7. In one embodiment, the chemisorption circuit
and the physisorption circuit can share the same ammonia vapor
recovery section as shown in FIG. 5 where the chemisorbent
canisters and the physisorption compressors share the same
condenser and evaporator means. In another embodiment the
chemisorption circuit and the physisorption circuit can be
independent as shown in FIG. 2 where the chemisorbent
canisters and the physisorption compressors each have their
own condenser and evaporator means.
FIG. 8 is a schematic diagram of another embodiment of this
invention, generally designated by numeral 159, showing the
working fluid circuit for a two stage compression
series/series regenerative heat pump process for cooling a
refrigeration space and a freezer space. FIG. 8 also has four
first stage and four second stage compression zones. The
working fluid circuit for the system of FIG. 8 is the same as
that for the system of FIG. 7 except for the addition of
second evaporator circuit 160. As shown in FIG. 8, branching
off of line 161 is line 162, which is connected to condenser
167, which is connected to line 164, which is in heat transfer
communication with line 176 in auxiliary heat exchanger 173,
which is connected to Joule-Thomson expansion valve 168, which
is connected to evaporator 169.
Evaporator 169, which contains a supply of liquid ammonia 171,
receives heat from a refrigerator zone, as indicated by arrow
175, thereby cooling the refrigerator zone. Ammonia vapor
flows from evaporator 169 to line 176, which is connected to
manifold 95, which delivers ammonia vapor to the second stage
compression zones at an intermediate pressure, thereby forming
a second closed working fluid loop.
Evaporator means 69 receives heat from a freezer zone, as
indicated by arrow 75, thereby cooling the freezer zone.
The heat transfer fluid circuit for the system of FIG. 8 is
the same as that for the system of FIG. 7, namely that shown
in FIG. 6.
Evaporator means 89 produces ammonia gas at about -18.degree.
C. and about 2 bar. Evaporator means 169 produces ammonia gas
at about +5.degree. C. and about 5 bar. Condensers 74 and 174
cool the ammonia gas and produce a condensate at about
38.degree. C. and about 15 bar.
FIG. 8 shows only the ammonia physisorption circuit. The
ammonia chemisorption circuit to be used with FIG. 8 is not
shown in FIG. 8. In one embodiment, the chemisorption circuit
and the portion of the ammonia vapor recovery physisorption
circuit downstream of the upper stage physisorption
compressor, i.e. line 88, and the upstream of the lower stage
physisorption compressor, i.e. line 87 can share the same
ammonia vapor recovery section. In other words condenser 67
and evaporator means 69 of FIG. 8 can be deleted and lines 87
and 88 of FIG. 8 can be connected to lines 57B and 57A,
respectively, of FIG. 5, and condenser 59 and evaporator means
62 used instead. In another embodiment the ammonia vapor
recovery circuit for the chemisorption circuit and the
physisorption circuit can be independent as shown in FIG. 2
where the chemisorbent canisters have their own condenser and
evaporator means.
FIG. 9 is another embodiment of this invention in which heat
transfer fluid circuit 23 of the lower temperature
physisorption side is the same as that shown in FIG. 1, but
single heat transfer fluid circuit 22 of FIG. 1 is replaced
with two separate heat transfer fluid loops, generally
designated collectively by numeral 101, each having its own
pump, external heat source, and four-way solenoid valve. In
operation flow from pump 102A is directed through heat
transfer element 33A in canister 24A to four-way solenoid
valve 103A which directs the heat transfer fluid to either
heat exchanger 29A or 29B, or directly back to pump 102A.
External heat source 104A is turned on when canister 24A is to
be heated. In a similar manner, flow from pump 102B is
directed through heat transfer element 33B in canister 24B to
four-way solenoid valve 103B which directs the heat transfer
fluid to either heat exchanger 29C or 29D, or directly back to
pump 102B. External heat source 104B is turned on when
canister 24B is to be heated.
Referring to FIG. 9, solenoid valves 44A, 44B, 44C and 44D,
47A, 47B, 47C, 47D, 103A and 103B are controlled by controller
means 105 so that only one valve of valve set 44 is open, and
only one valve of valve set 47 is open, so that inlet line
108A is in fluid communication with the only one of outlet
lines 107A, 107B or 107P, so that inlet line 108B is in fluid
communication with the only one of outlet lines 107C, 107D or
107R, for a predetermined period of time during the base part
and bottoming part of each phase. Controller means 105 further
prevents heat cascading during the bottoming part of each
phase by stopping pump 102A and 102B, and pumping the heat
transfer fluid directly from pump 42 to a predetermined
compressor and therefrom directly to radiator 51. Controller
means 105 also controls external heat sources 104A and 104B so
that heating of heat transfer fluid in lines 108A and 108B
occurs only as need to maintain the temperature of canisters
24A and 24B at a predetermined value.
When the system of FIG. 9 is operated, with CoBr.sub.2 as the
working fluid-chemisorbent pair, with desorption at
215.degree. C. and 15 bar, with adsorption at 175.degree. C.
and 5 bar, the chemisorbent system has a COP.sub.C of about
0.35; and with ammonia-carbon as the working
fluid-physisorbent pair, with desorption at 170.degree. C. and
15 bar, and with adsorption at 40.degree. C. and 5 bar, the
physisorbent system has a COP.sub.C of about 1.0; with a
combined COP.sub.C of about 1.35.
The operation of the heat transfer circuits for all of the
above described embodiments illustrated in FIGS. 1 to 9 is
determined by heat and ammonia sorption rates for the
particular system in use and the cycling of the solenoid
valves is control in a predetermined manner to achieve maximum
efficiency for the system.
FIG. 10 is a schematic flow diagram of one embodiment of this
invention, of a heat transfer fluid circuit of a higher
temperature chemisorption circuit, generally designated by
numeral 110, powering a lower temperature absorber heat
exchange (AHE) system, generally designated by numeral 111.
The heat transfer fluid circuit of higher temperature
chemisorption circuit 110 comprises heat transfer elements 33A
and 33B, solenoid valves 148A and 148B, pump 150, external
heat sources 152A and 152B, and controller means 154. Means
154 controls the flow of heat transfer fluid through heat
transfer elements 33A and 33B by opening and closing solenoid
valves 148A and 148B for a predetermined period of time,
respectively. Means 154 also control external heat sources
152A and 152B so that only one is actually heating its
corresponding canister (24A or 24B) at a time. As shown in
FIG. 10, canister 24A is being heated, solenoid valve 148B is
open and 148A closed thereby directing hot heat transfer fluid
from canister 24B to coil 117 in generator 115, to pump 150
and back to canister 24B. After a predetermined period of time
the chemisorbent in canister 24A is desorbed a predetermined
amount, external heat source 152A is turned off and 152B
turned on, valve 148B is closed and 148A opened, and the
process repeated in a similar manner for heating canister 24B.
In AHE system 111 ammonia-water solution 113 at about
116.degree. C. and 15 bar in generator 115, is heated by waste
heat provided by higher temperature heat transfer fluid loop
of chemisorption circuit 110, and specifically by heating coil
117. Heat from rectifier section 147 of generator 115 is
transferred to the environment by radiator 118 as .indicated
by arrow 120. Distilled and rectified high pressure ammonia
vapor 119 at about 15 bar is removed from the generator
through line 121 and charged to condenser 123 wherein the heat
of condensation is transferred to the environment as indicated
by arrow 124, and low temperature, high pressure ammonia
condensate 125 at about 38.degree. C. is formed. The liquid
ammonia is cooled further in heat exchanger 127, expanded
through Joule-Thomson valve 129, and charged to evaporator
means 131 wherein the heat of evaporation is provided by low
temperature heat load, such as an interior building space, as
indicated by arrow 132, to vaporize the ammonia liquid and
produce a low temperature, low pressure ammonia gas 133 at
about 5.degree. C. This gas is heated in heat exchanger 127
and then charged to absorber 139 through line 140. A stream of
weak high pressure ammonia-water solution 113 from generator
115 is cooled in heat exchanger 135, expanded through
Joule-Thomson valve 137, and charged to absorber 139 together
with a stream of cooled, low pressure ammonia vapor conveyed
by line 140 from heat exchanger 127. The ammonia vapor stream
is absorbed by the weak ammonia-water solution stream in
absorber 139 at about 38.degree. C. to produce strong
ammonia-water solution 141 which is collected in absorber 139,
with the heat of absorption being exhausted to the environment
as indicated by arrow 142. A stream of strong ammonia-water
solution 143 is pumped by pump 144 at about 15 bar through
heat exchanger 135 to distillation section 145 of generator
115 wherein ammonia is stripped from the solution at about 15
bar along with some water vapor. Most of the water vapor is
separated from the ammonia vapor in rectifier section 147 with
the separated water returning to distillation section 145 and
the bottom section of generator 115, thereby completing the
absorption-desorption cycle.
When the system of FIG. 10 is operated, with SrBr.sub.2 as the
working fluid-chemisorbent pair, with desorption at
160.degree. C. and 15 bar, with chemisorption at 120.degree.
C. and 5 bar, the chemisorbent system has a COP.sub.C of about
0.35; and with AHE system 111 as the lower temperature
circuit, with desorption in generator 115 at 115.degree. C.
and 15 bar, and with absorption in absorber 139 at 38.degree.
C. and 5 bar, the AHE system has a COP.sub.C of about 0.6;
with a combined COP.sub.C of about 1.1.
FIG. 11 is a schematic flow diagram of another embodiment of
this invention similar in some respects to FIG. 10, of a heat
transfer fluid circuit of a higher temperature chemisorption
circuit, generally designated by numeral 180, powering a lower
temperature absorber heat exchange (AHE) system, generally
designated by numeral 111. In this embodiment, lower
temperature AHE circuit 111 is the same as that described for
FIG. 10.
The heat transfer fluid circuit of higher temperature
chemisorption circuit 180 comprises heat transfer elements 33A
and 33B, three-way solenoid valves 182 and 184, pumps 188 and
188, external heat sources 190A and 190B, and controller means
192. Means 192 controls the flow of heat transfer fluid
through heat transfer elements 33A and 33B by directing flow
through three-way solenoid valves 182 and 184 for
predetermined periods of time, and activating pumps 188 and
188. Means 192 also control external heat sources 190A and
190B so that only one is actually heating its corresponding
canister (24A or 24B) at a time.
In FIG. 11, while canister 24A is being heated by external
heat source 190A, pumps 188 and 188 are activated, solenoid
valve 182 is open to flow only from line 193C to 193A,
solenoid valve 184 is open to flow only from line 194B to
194C, thereby directing hot heat transfer fluid from canister
24B to coil 117 in generator 115, to pump 188 and back to
canister 24B. After a predetermined period of time the
chemisorbent in canister 24A is desorbed a predetermined
amount, external heat source 190A is turned off, pump 188 is
deactivated, solenoid valve 182 is opened to flow only from
line 193B to 193A, solenoid valve 184 is opened to flow only
from line 194A to 194B, thereby directing hot heat transfer
fluid from canister 24A to pump 188, to canister 24B and back
to canister 24A. Heat is regenerated during this phase by
transferring heat from hotter canister 24A to cooler canister
24B. After a predetermined period of time heat regeneration is
completed and pump 188 is deactivated.
In the next phase, canister 24B is heated by external heat
source 190B, pump 188 is activated, solenoid valve 182 is
opened to flow only from line 193C to 193A, solenoid valve 184
is opened to flow only from line 194A to 194C, thereby
directing hot heat transfer fluid from pump 188 to canister
24A, to coil 117 in generator 115 and back to pump 188. After
a predetermined period of time the chemisorbent in canister
24B is desorbed a predetermined amount, the chemisorbent in
canister 24A is absorbed a predetermined amount, external heat
source 190B is turned off, solenoid valve 182 is opened to
flow only from line 193B to 193A, and solenoid valve 184 is
opened to flow only from line 194A to 194B, thereby directing
hot heat transfer fluid from canister 24B, to canister 24A, to
pump 188 and back to canister 24B. Heat is regenerated during
this phase by transferring heat from hotter canister 24B to
cooler canister 24A. After a predetermined period of time heat
regeneration is completed and pump 188 is deactivated, thereby
completing a cycle in higher temperature chemisorption circuit
180. The cycle is then repeated.
The operation of AHE system 111 is the same as described for
FIG. 10.
It has been calculated that when the system of FIG. 11 is
operated, with either ammonia-CaBr.sub.2 or ammonia-SrBr.sub.2
as the working fluid-chemisorbent pair, either with or without
heat regeneration in higher temperature chemisorption circuit
180, with desorption at 15 bar, with chemisorption at 5 bar,
the chemisorbent system will have a COP.sub.C ranging from
about 0.40 to about 0.43; see Tables 2 to 5. Combined with AHE
system 111 as the lower temperature circuit, with desorption
in generator 115 at 15 bar, and with absorption in absorber
139 at 38.degree. C. and 5 bar, with the AHE system having a
COP.sub.C of about 0.6, the combined COP.sub.C will be from
about 1.00 to about 1.03.
Tables 2 to 5 represent analytical computer calculations using
a computer program designated RSORB, for two different choices
of higher temperature chemisorbents of FIG. 11.
The input and output data of Table 2 correspond to
chemisorbent 24A and 24B being CaBr.sub.2 with no internal
heat regeneration in the chemisorption circuit.
The input and output data of Table 3 correspond to
chemisorbent 24A and 24B being CaBr.sub.2 with internal heat
regeneration in the chemisorption circuit.
The input and output data of Table 4 correspond to
chemisorbent 24A and 24B being SrBr.sub.2 with no internal
heat regeneration in the chemisorption circuit.
The input and output data of Table 5 correspond to
chemisorbent 24A and 24B being SrBr.sub.2 with internal heat
regeneration in the chemisorption circuit.
When the chemisorption circuit is operated with internal heat
regeneration, as in Tables 3 and 5, each desorption step is
required to be followed by a regeneration step which comprises
circulating the heat transfer fluid through the loop
comprising canister 24A and 24B and pump 188, during which
external heat sources 190A and 190B are off. This heat
regeneration step is omitted for the data presented in Tables
2 and 4.
The cooling coefficients of performance, or COP.sub.C, for
these four embodiments are generally seen to be from about
0.40 to about 0.43 or a specific power from about 2.50628 to
about 2.31714 as shown in Tables 2 to 5.
FIG. 12 is a schematic flow diagram of another embodiment of
this invention, of a heat transfer fluid circuit of a higher
temperature chemisorption circuit, generally designated by
numeral 180, powering a lower temperature generator-absorber
heat exchange (GAX) system, generally designated by numeral
211. The operation of higher temperature chemisorption circuit
180 is the same as that described for FIG. 11.
In lower temperature GAX system 211, a weak ammonia-water
solution 213 in the bottom portion of generator 215, is heated
by waste heat provided by higher temperature heat transfer
fluid loop of chemisorption circuit 180, and specifically by
heating coil 117, to produce ammonia vapor 219 at about
50.degree. C. and about 15 bar. The high pressure ammonia
vapor 219 flows from the generator through line 221 to
condenser 223 wherein the gaseous ammonia stream is cooled and
condensed, the heat of condensation transferred to the
environment as indicated by arrow 224, and a low temperature,
high pressure ammonia condensate 225 at about 40.degree. C.
and about 15 bar is formed. A stream of liquid ammonia from
condenser 223 is expanded through Joule-Thomson valve 229 to
produce low temperature, low pressure ammonia liquid 233 at
about 4.degree. C. and about 5 bar, which is then charged to
evaporator means 231. A low temperature heat load, such as an
interior building space, provides the heat of evaporation, as
indicated by arrow 232, to vaporize the ammonia liquid in
evaporator means 231 and produce low temperature, low pressure
ammonia gas 233 at about 4.degree. C. and about 5 bar, which
is charged to absorber 239 through line 240.
A stream of weak high pressure ammonia-water solution 214 from
generator 215 at about 150o.degree. C. and about 15 bar is
expanded through Joule-Thomson valve 237, and charged to
absorber 239 and contacted with the stream of low pressure
ammonia vapor conveyed by line 240 from evaporator 231. The
ammonia vapor stream is absorbed by the weak ammonia-water
solution stream in absorber 239 to produce strong
ammonia-water solution 241 which is collected in the bottom of
absorber 239. A heat transfer fluid is pumped in a closed loop
through heat exchange means 250 in heat exchange section 252
of absorber 239, and through heat exchange means 254 in heat
exchange section 253 of generator 215. A portion of the heat
of absorption is exhausted to the environment as indicated by
arrow 242. Another portion of the heat of absorption is
recovered by pumping a stream of strong ammonia-water solution
243 is pumped by pump 244 at about 40.degree. C. and about 5
bar from the bottom section of absorber 239 through heat
exchange section 235 of absorber 239, to section 245 of
generator 215 wherein ammonia is stripped from the strong
solution at about 150.degree. C. and about 15 bar, thereby
forming ammonia vapor stream 219 and weak ammonia-water
solution 213 which is collected in the bottom section of
generator 215, thereby completing the absorption-desorption
cycle.
The operation of the heat transfer circuits for the
embodiments illustrated in FIGS. 10 to 12 is determined by
heat and ammonia sorption rates for the particular system in
use, and is controlled in a predetermined manner by
controllers 154 and 192 to achieve maximum efficiency for the
system.
TABLE 1
__________________________________________________________________________
Pump
Opened Sol- Time Temperature (.degree.C.) at Point 35 enoid
Valve (min) T1 T2 T3 T4 T5 T6 T7 Flow 30 44 47 Comment
__________________________________________________________________________
Phase
1 0 170 180 220 225 175 75 R-L A D D 45A being heated 1 180
225 175 220 170 175 90 R-L A D D 45A being heated 2 220 225
170 180 165 215 175 R-L A D D 24A & 45A desorbing, 24B
sorbing 2.01-3 Off D C 45C bottoming Phase 2 3.01 220 225 170
180 175 75 L-R D C C 45D being heated 4 175 220 180 225 170
175 90 L-R D C C 45D being heated 5 170 180 220 225 165 215
175 L-R D C C 24B & 45D desorbing, 24A sorbing 5.01-6 Off
C B 45C bottoming Phase 3 6.01 170 180 220 225 175 75 R-L C B
B 45A being heated 7 180 225 175 220 170 175 90 R-L C B B 45A
being heated 8 220 225 170 180 165 215 175 R-L C B B 24A &
45C desorbing, 24B sorbing 8.01-9 Off B A 45C bottoming Phase
4 9.01 220 225 170 180 175 75 L-R B A A 45A being heated 10
175 220 180 225 170 175 90 L-R B A A 45A being heated 11 170
180 220 225 165 215 175 L-R B A A 24B & 45B desorbing, 24B
sorbing 11.01-12 Off A D 45C bottoming
__________________________________________________________________________
R-L
= Flow from right to left through pump 35 of FIG. 3 L-R = Flow
from left to right through pump 35 of FIG. 3
TABLE 2 ______________________________________ CaBr.sub.2
AMMONIA CHEMISORPTION STAGE NO INTERNAL HEAT REGENERATION
______________________________________ INPUTS JT temperature
(K.) 277.00000 JT cooling load (W) 10548.00000 Effective
ambient temperature (K.) 200.00000 Sorbent density (gm/cc)
1.00000 Void volume (%) 70.00000 Heat of formation (kcal/mol)
10.51000 Cp of sorbant with gas (cal/gm K) 0.56300 Sorbant low
temperature (K.) 404.00000 Sorbant high temperature (K.)
441.00000 Sorbant low pressure (atm) 5.00000 Sorbant high
pressure (atm) 15.00000 Delta (Mgas/Msorbant) 0.22500 Gas
molecular weight 17.00000 Total cycle time to heat and cool
(sec) 360.00000 Core density (gm/cc) 2.71000 Compressor case
density (gm/cc) 7.92000 Core Cp (cal/gm K) 0.24000 Compressor
case Cp (cal/gm K) 0.12000 Compressor case yield strength
(ksi) 100.00000 Compressor ID (cm) 5.00000 Core volume (%)
10.00000 HX precooling temperature (K.) 311.00000 Low pressure
enthalpy at precool (cal/gm) 294.00000 High pressure enthalpy
at precool (cal/gm) 0.00000 HX efficiency (fraction) 0.98000
Low pressure gas cp in HX (cal/gm K) 0.56000 OUTPUTS Gas flow
rate (gm/sec) 8.58606 Compressor case thickness with four fold
safety (cm) 0.02215 Total compressor lengths (cm) 788.39558
Sorbent mass (kg) 13.93213 Metal core mass (kg) 4.19512 Metal
case mass (kg) 2.18196 Total compressor mass (kg) 20.30921
Compressor radiator area (sq meters) 20.68946 Compressor
radiator mass (kg) 103.44730 Sorbent and gas sensible heat (W)
3372.19811 Sorbent heat of formation (W) 22518.49049 Core heat
required (W) 432.95875 Case heat required (W) 112.59483 Total
heat required (W) 26436.24218 Specific power (W/W) =
1/COP.sub.c 2.50628 ______________________________________
TABLE 3 ______________________________________ CaBr.sub.2
AMMONIA CHEMISORPTION STAGE WITH INTERNAL HEAT REGENERATION
______________________________________ INPUTS JT temperature
(K.) 277.00000 JT cooling load (W) 10548.00000 Effective
ambient temperature (K.) 200.00000 Sorbent density (gm/cc)
1.00000 Void volume (%) 70.00000 Heat of formation (kcal/mol)
10.51000 Cp of sorbent with gas (cal/gm K) 0.32100 Sorbent low
temperature (K.) 404.00000 Sorbent high temperature (K.)
441.00000 Sorbent low pressure (atm) 5.00000 Sorbent high
pressure (atm) 15.00000 Delta (Mgas/Msorbent) 0.22500 Gas
molecular weight 17.00000 Total cycle time to heat and cool
(sec) 360.00000 Core density (gm/cc) 2.71000 Compressor case
density (gm/cc) 7.92000 Core Cp (cal/gm K) 0.00000 Compressor
case Cp (cal/gm K) 0.00000 Compressor case yield strength
(ksi) 100.00000 Compressor ID (cm) 5.00000 Core volume (%)
10.00000 HX precooling temperature (K.) 311.00000 Low pressure
enthalpy at precool (cal/gm) 294.00000 High pressure enthalpy
at precool (cal/gm) 0.00000 HX efficiency (fraction) 0.98000
Low pressure gas Cp in HX (cal/gm K) 0.56000 OUTPUTS Gas flow
rate (gm/sec) 8.58606 Compressor case thickness with four fold
safety (cm) 0.02215 Total compressor lengths (cm) 788.39558
Sorbent mass (kg) 13.93213 Metal core mass (kg) 4.19512 Metal
case mass (kg) 2.18196 Total compressor mass (kg) 20.30921
Compressor radiator area (sq meters) 19.12809 Compressor
radiator mass (kg) 95.64046 Sorbent and gas sensible heat (W)
1922.69200 Sorbent heat of formation (W) 22518.49049 Core heat
required (W) 0.00000 Case heat required (W) 0.00000 Total heat
required (W) 24441.18249 Specific power (W/W), = 1/COP.sub.c
2.31714 ______________________________________
TABLE 4 ______________________________________ SrBr.sub.2
AMMONIA CHEMISORPTION STAGE NO INTERNAL HEAT REGENERATION
______________________________________ INPUTS JT temperature
(K.) 277.00000 JT cooling load (W) 10548.00000 Effective
ambient temperature (K.) 200.00000 Sorbent density (gm/cc)
1.26000 Void volume (%) 70.00000 Heat of formation (kcal/mol)
10.54000 Cp of sorbent with gas (cal/gm K) 0.57500 Sorbent low
temperature (K.) 393.00000 Sorbent high tmperature (K.)
433.00000 Sorbent low pressure (atm) 5.00000 Sorbent high
pressure (atm) 15.00000 Delta (Mgas/Msorbent) 0.26600 Gas
molecular weight 17.00000 Total cycle time to heat and cool
(sec) 360.00000 Core density (gm/cc) 2.71000 Compressor case
density (gm/cc) 7.92000 Core Cp (cal/gm K) 0.24000 Compressor
case Cp (cal/gm K) 0.12000 Compressor case yield strength
(ksi) 100.00000 Compressor ID (cm) 5.00000 Core volume (%)
10.00000 HX precooling temperature (K.) 311.00000 Low pressure
enthalpy at precool (cal/gm) 294.00000 High pressure enthalpy
at precool (cal/gm) 0.00000 HX efficiency (fraction) 0.98000
Low pressure gas Cp in HX (cal/gm K) 0.56000 OUTPUTS Gas flow
rate (gm/sec) 8.58606 Compressor case thickness with four fold
safety (cm) 0.02215 Total compressor lengths (cm) 526.88089
Sorbent mass (kg) 11.73158 Metal core mass (kg) 2.80358 Metal
case mass (kg) 1.45819 Total compressor mass (kg) 15.99335
Compressor radiator area (sq meters) 22.90356 Compressor
radiator mass (kg) 114.51781 Sorbent and gas sensible heat (W)
3135.23145 Sorbent heat of formation (W) 22480.97263 Core heat
required (W) 312.80454 Case heat required (W) 81.34765 Total
heat required (W) 26010.35626 Specific power (W/W) =
1/COP.sub.c 2.46590 ______________________________________
TABLE 5 ______________________________________ SrBr.sub.2
AMMONIA CHEMISORPTION STAGE WITH INTERNAL HEAT REGENERATION
______________________________________ INPUTS JT temperature
(K.) 277.00000 JT cooling load (W) 10548 00000 Effective
ambient temperature (K.) 200.00000 Sorbent density (gm/cc)
1.26000 Void volume (%) 70.00000 Heat of formation (kcal/mol)
10.54000 Cp of sorbent with gas (cal/gm K) 0.37400 Sorbent low
temperature (K.) 393.00000 Sorbent high temperature (K.)
433.00000 Sorbent low pressure (atm) 5.00000 Sorbent high
pressure (atm) 15.00000 Delta (Mgas/Msorbent) 0.26600 Gas
molecular weight 17.00000 Total cycle time to heat and cool
(sec) 360.00000 Core density (gm/cc) 2.71000 Compressor case
density (gm/cc) 7.92000 Core Cp (cal/gm K) 0.00000 Compressor
case Cp (cal/gm K) 0.00000 Compressor case yield strength
(ksi) 100.00000 Compressor ID (cm) 5.00000 Core volume (%)
10.00000 HX precooling temperature (K.) 311.00000 Low pressure
enthalpy at precool (cal/gm) 294.00000 High pressure enthalpy
at precool (cal/gm) 0.00000 HX efficiency (fraction) 0.98000
Low pressure gas Cp in HX (cal/gm K) 0.56000 OUTPUTS Gas flow
rate (gm/sec) 8.58606 Compressor case thickness with four fold
safety (cm) 0.02215 Total compressor lengths (cm) 526.88089
Sorbent mass (kg) 11.73158 Metal core mass (kg) 2.80358 Metal
case mass (kg) 1.45819 Total compressor mass (kg) 15.99335
Compressor radiator area (sq meters) 21.59143 Compressor
radiator mass (kg) 107.95714 Sorbent and gas sensible heat (W)
2039.26359 Sorbent heat of formation (W) 22480.97263 Core heat
required (W) 0.00000 Case heat required (W) 0.00000 Total heat
required (W) 24520.23621 Specific power (W/W) = 1/COP.sub.c
2.32463 ______________________________________