GB2126706A - Combined adsorption and absorption heat pump - Google Patents
Combined adsorption and absorption heat pump Download PDFInfo
- Publication number
- GB2126706A GB2126706A GB08225142A GB8225142A GB2126706A GB 2126706 A GB2126706 A GB 2126706A GB 08225142 A GB08225142 A GB 08225142A GB 8225142 A GB8225142 A GB 8225142A GB 2126706 A GB2126706 A GB 2126706A
- Authority
- GB
- United Kingdom
- Prior art keywords
- heat
- heat pump
- condenser
- pump
- adsorption
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B29/00—Combined heating and refrigeration systems, e.g. operating alternately or simultaneously
- F25B29/006—Combined heating and refrigeration systems, e.g. operating alternately or simultaneously of the sorption type system
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Sorption Type Refrigeration Machines (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
Abstract
An absorption heat pump comprising a generator (1), a condenser (4), an evaporator (3) and an absorber (2) is coupled to an adsorption heat pump (16) comprising an adsorber (19) and an evaporator/condenser (20), and wherein there are means (8) for transferring heat of condensation from the condenser (4) alternately to the external load (28, 29) and to the evaporator/condenser (20). There are means (18) for transferring heat of adsorption and sensible heat from the adsorber (19) to the generator (1). <IMAGE>
Description
1
GB 2 126 706 A 1
SPECIFICATION A tandem heat pump
This invention relates the coupling of an adsorption heat pump with an absorption heat 5 pump.
Absorption heat pumps which are capable of pumping heat from temperatures below 0°C have poor coefficients of performance (C.O.P.). Thus an ammonia/water machine which pumps heat from 10 —5°C to 50°C could require a heat input temperature of about 130°C and might have a C.O.P. of about 1.4. If it were possible to drive such a heat pump with the output of an adsorption heat pump, pumping heat from the same source, 15 then the overall C.O.P. would be much improved. Unfortunately, however a very high temperature lift of the adsorption heat pump would be required in order to achieve this and it would not be possible to use a water/zeolite system as the 20 adsorbate/adsorbent (which is of course cheap as far as adsorbate is concerned) because of the freezing point limitations.
However we have devised a compromise wherein the heat used to drive the absorption heat 25 pump is first used to drive an adsorption heat pump which is used to pump heat from the condenser of the absorption heat pump to its generator. Heat pumped in this way induces a similar flow of heat from the evaporator of the 30 absorption heat pump to its absorber. The overall effect is to increase the C.O.P. of the system by the heat pumped by the adsorption unit.
Thus, if the C.O.P. of the absorption heat pump is 1.4 and that of the adsorption heat pump is 1.4 35 the overall C.O.P. will be about 1.8.
In accordance with this invention a process of operating an absorption heat pump coupled to an adsorption heat pump is one wherein heat of condensation is delivered from the condenser of 40 the absorption heat pump alternately to the external load and to the adsorption heat pump for use in vaporising adsorbate to be adsorbed by adsorbent and wherein heat of adsorption and sensible heat are transferred from the adsorption 45 heat pump to the generator of the absorption heat pump.
When the heat of condensation is delivered from its condenser to the load the absorption heat pump operates normally, that is to say absorbate 50 is driven off from the generator by heat supplied indirectly from the adsorber, vaporised absorbate is condensed in the condenser, rejecting heat of condensation, condensed absorbate after being expanded is sent to the evaporator where it 55 evaporates and from the evaporator vaporised absorbate is delivered to the absorber where the heat of absorption is rejected. Weak working fluid solution is pumped from the absorber to the generator and strong working fluid solution is 60 delivered from the generator to the absorber via an expansion valve.
When the heat of condensation is delivered to the adsorption heat pump this heat is used to vaporise adsorbate which is then adsorbed by adsorbent causing evolution of heat of adsorption. The heat of adsorption is used to supply heat to the generator of the absorption heat pump.
The transference of heat in the process of the invention is usually by indirect heat exchange. Thus, heat of condensation evolved in the condenser of the absorption heat pump may be transferred by way of a heat exchanger heat pump may be transferred by way of a heat exchanger located within the condenser, conduits having valves and a pump to a heat exchanger, located in the evaporator/condenser of the adsorption heat pump. Similarly heat is supplied to the adsorbent in the adsorber preferably by indirect heat exchange and heat may be transferred from the adsorber to the generator of the absorption heat pump through heat exchangers located within the adsorber and the generator interconnected by conduits, valves and pumps. Heat may be supplied to the adsorber for desorbing the adsorbent by means of a resistive heater or by means of the circulation through a heat exchanger of heat transfer fluid heated by a boiler.
In the adsorber the preferred adsorbent/adsorbate system is Y-zeolite molecular sieve/water. Alternatively 4A-zeolite molecular sieve/water, 3A-zeolite molecular sieve/water can be used.
The working fluid used in the absorption heat pump is preferably a solution of ammonia (absorbate) in water (absorbent).
A suitable heat transfer fluid for use in the heat exchangers and in the connecting conduits is a low vapour pressure liquid, for example a silicon liquid, e.g. Dow Syltherm 800. Other suitable fluids are thermally stabilised aromatic hydrocarbons.
In the preferred process of the invention there are three distinct stages. During desorption of the adsorbate from the adsorbent in the adsorber, the absorption heat pump works in its normal manner and heat is delivered to the load both from the condenser and from the absorber. Relatively low temperature heat is accepted at the evaporator. The desorbed adsorbate is condensed in the evaporator/condenser of the adsorption heat pump and the heat of condensation is transferred by heat exchange to the generator of the absorption heat pump.
In the next stage after desorption of the adsorbate, the absorption heat pump still works in its normal manner as outlined immediately above, but sensible heat is transferred by heat exchange from the adsorber to the generator of the absorption heat pump.
In the last stage when the temperature of the adsorber has dropped to an appropriate level, the heat of condensation from the condenser of the absorption heat pump is transferred by heat exchange to the evaporator/condenser of the adsorption heat pump where condensed adsorbate is evaporated and is adsorbed by the adsorbent. The heat of adsorption thus produced is transferred by heat exchange to the generator of the adsorption heat pump.
65
70
75
80
85
90
95
100
105
110
115
120
125
2
GB 2 126 706 A 2
Since in the two pumps the ratios of the heats of the evaporation to the heats of sorption are similar the coupled pumps are closely in thermal balance. The effect of pumping heat from the 5 condenser in the absorption heat pump to its generator is to cause heat accepted by its evaporator to be transferred to its absorber and from there to the external load. When considering the system as a whole heat is only accepted from 10 a low temperature source via the evaporator of the absorption heat pump and heat is pumped via the adsorption heat pump in two stages. This allows the use of water as the working fluid in the adsorption heat pump even when the temperature 15 of the heat source is below 0°C and allows the C.O.P. of the system as a whole to be substantially improved.
Apparatus for carrying out the process of the invention comprises an absorption heat pump 20 coupled to an adsorption heat pump wherein there are means for transferring by heat exchange heat of condensation from the condenser of the absorption heat pump alternately to the external load and to the evaporator/condenser of the 25 adsorption heat pump. There are also means for transferring heat of adsorption and sensible heat from the adsorption heat pump to the generator of the absorption heat pump.
The absorption heat pump is conventional and 30 comprises a generator, an absorber, an evaporator and a condenser.
The evaporator is designed to house the absorbate solution and to receive heat from a low temperature source, e.g. ambient air, either 35 directly or indirectly.
There is an absorber in communication, e.g., by conduit, with the evaporator. The transfer of heat generated in the absorber to the load is preferably by means of a heat exchanger.
40 Connected to the absorber in the usual manner for an absorption system is a generator. There are two separate conduits connecting together the absorber and the generator, one conduit being provided with an expansion valve. Weak working 45 fluid is conveyed from the absorber to the generator through the non-valved conduit by a solution pump, whilst strong working fluid from the generator is conveyed to the absorber through the conduit having the expansion valve. 50 The absorption system includes a condenser communicating e.g. by conduits with both the generator and the evaporator. Absorbate vapour passes from the generator to the condenser where it condenses. Condensed absorbate passes to the 55 evaporator after passing through an expansion valve.
The adsorption heat pump can be a series of trays housing adsorbent below which is a condenser/evaporator. Such a form of adsorption 60 heat pump is described in our copending patent application, GB.8222333. In this form of adsorption heat pump adsorbate when desorbed from the adsorbent is allowed to condense in the condenser/evaporator. At another stage in the 65 process of using this adsorption heat pump, when heat is supplied to the condenser/evaporator the condensed adsorbate is evaporated and this rises and is adsorbed by the adsorbent housed in the trays. The heat of adsorption can be transferred elsewhere by means of a heat exchanger associated with the trays.
The means for transferring heat in the apparatus of the invention are preferably heat exchangers. There are heat exchangers associated with all four units of the absorption heat pump and with the two units of the adsorption heat pump. Preferably these heat exchangers are located inside each unit. Thus, for example a heat exchanger is located within the condenser of the absorption heat pump rather than outside this condenser. Conduits and where necessary, valves and pumps are used to interconnect the various heat exchangers.
Preferably there is a header tank connected to the conduits interconnecting the heat exchangers. This tank contains heat transfer fluid and this will enable any lost heat transfer fluid in the system to be replenished.
The apparatus suitable for carrying out the process of the invention is shown schematically in the accompanying drawing.
The absorption heat pump comprises a generator 1, connected by conduits 9 and 10 to an absorber 2. Absorber 2 is connected by conduit 13 to an evaporator 3 which in turn is connected by conduit 14 to condenser 4. A conduit 16 connects the condenser 4 with the generator 1. A circulating pump 11 is provided in conduit 9 and there is an expansion valve 12 in conduit 10 and an expansion valve 15 in conduit 14. There are heat exchangers 5, 6, 7 and 8 located respectively in generator 1, absorber 2, evaporator 3 and condenser 4.
The absorption heat pump 16 comprises trays of Y-type zeolite molecular sieve in the upper part 19 which is the adsorber and in which heat exchangers 17 and 18 are located. In the lower part 20 of the heat pump 16 which is the evaporator/condenser is located a heat exchanger 21. This heat exchanger 21 is connected by conduit 22 and valve 24 to heat exchanger 8 and also connected to this heat exchanger 8 by conduit 25, valve 26 and circulation pump 27. Conduits 22 and 25 are also connected respectively to conduits 28 and 29 which lead to the external load, conduit 29 being provided with a valve 30.
Heat exchanger 18 is connected to heat exchanger 5 by means of conduits 31 and 32, the former being provided with a valve 33 and a circulation pump 34. Conduit 32 is connected to conduit 25 by means of conduit 35 having valve 36.
There is a header tank 37 housing heat transfer fluid which in this case is Dow Syltherm 800 and this tank 37 is connected by conduit 38 to conduit 22.
Heat is supplied to the adsorber 19 at about 300°C through the heat exchanger 17 through which Dow Syltherm 800 circulates, the heat
70
75
80
85
90
95
100
105
110
115
120
125
130
3
GB 2 126 706 A 3
being derived from a boiler.
The apparatus operates as follows:
Whilst water is desorbed from the zeolite in the adsorber 19 by application of heat at high 5 temperature through heat exchanger 17, valves 24,26 and 33 are closed and valves 30 and 36 are opened.
The absorption heat pump will be working normally, i.e., low temperature heat at about 10 —5°C will be accepted through heat exchanger 7 in the evaporator 3 and delivered at a temperature of about 50°C to the external load through heat exchanger 6 located in the absorber 2. Weak working fluid, i.e., aqueous ammonia, will be 15 pumped from absorber 6 by pump 11 through conduit 9 to the generator 1 whilst strong aqueous ammonia passes from the generator 1 through conduit 10, expansion valve 12 to the absorber 2. Ammonia vapour also passes through 20 conduit 16 from the generator 1 to the condenser 4 where it condenses rejecting heat of condensation. Liquid ammonia passing through conduit 14 expands through expansion valve 15 and passes to the evaporator 3 where it 25 evaporates. From the evaporator 3 vaporised ammonia passes to the absorber 2 where it is absorbed in the aqueous ammonia solution, giving up heat of absorption to the heat exchanger 6.
Externa! heat is also provided by the heat of 30 condensation in the condenser 4 being transferred to heat exchanger 8 from which heat is abstracted for delivery to the external load through the flow of heat transfer fluid through conduits 28 and 29, pump 27 and open valve 30.
35 The water vapour desorbed from the zeolite is condensed in the condenser/evaporator 20 and the heat of condensation is transferred from the heat exchanger 21 through flow of heat transfer fluid via conduits 25,35 and 32, valve 36 being 40 open, to the heat exchanger 5 in the generator and back to the condenser/evaporator 20 via conduit 31, circulation pump 34, conduits 38 and 22 and open valve 23.
In the next stage at the conclusion of the 45 desorption operation valve 36 is shut and valve 33 is opened. Valve 30 remains open and valves 24 and 26 remain closed.
Sensible heat from the adsorber 19 is now transferred to the generator 1. This is achieved by 50 the circulation of the heat transfer fluid from heat exchanger 18 through conduit 31 via valve 33 by means of pump 34 to the heat exchanger 5 and back to the heat exchanger 18 via conduit 32. During this operation the absorption heat pump 55 still operates as before.
In the final stage when the temperature of the adsorber 19 has reached 150°C, valve 30 is closed and valves 24 and 26 are opened. Valve 36 remains closed and valve 33 remains open. 60 With pump 27 operating the heat of condensation from the condenser 4 is transferred from the heat exchanger 8 to heat exchanger 21 by flow of heat transfer fluid through conduit 22, open valve 24 to the heat exchanger 21 and back 65 to the heat exchanger 8 by way of conduit 25,
open valve 26 and pump 27. Whilst this is happening no heat is being delivered to the external load from the condenser 4.
The heat received by heat exchanger 21 located in the evaporator/condenser 20 causes water (adsorbate) to evaporate and this is adsorbed by the zeolite in the adsorber 19. The heat of adsorption thus produced is transferred from heat exchanger 18 to heat exchanger 5 located in the generator by means of the circulation of the heat transfer fluid through conduit 31, open valve 33, pump 34 and back via conduit 32.
During this operation the absorption heat pump works as before with the exception that the heat of condensation is transferred to the evaporator/condenser 20 rather than being supplied to the external load.
The three stages of the process of the invention can be repeated indefinitely and heat pumped from a temperature about —5°C (received in the evaporator 3) to a temperature of about 50°C (delivered from condenser 4 and absorber 2).
Automatic means, e.g., temperature sensors and a microprocessor, can be provided for opening and shutting the valves when required.
Claims (10)
1. A process of operating an absorption heat pump comprising a generator, a condenser, an evaporator and an absorber, said absorption pump being coupled to an adsorption heat pump comprising an adsorber and an evaporator/condenser which comprises delivering heat of condensation from the condenser of the absorption heat pump alternatively to the external load and to the evaporator/condenser for vaporisation of the adsorbate and transferring heat of adsorption and sensible heat from the adsorber of the adsorption heat pump to the generator of the absorption heat pump.
2. A process according to claim 1 wherein the absorbent in Y-zeolite molecular sieve and the adsorbate is water.
3. A process according to either of claims 1 and 2 wherein the working fluid in the absorption heat pump is aqueous ammonia.
4. A process according to any one of the preceding claims wherein the heat is transferred by indirect heat exchange.
5. A process of operating an absorption heat pump coupled to an adsorption heat pump substantially as hereinbefore described with reference to the drawing.
6. An apparatus suitable for carrying out the process according to any one of the preceding claims in which an absorption heat pump comprising a generator, a condenser, an evaporator and an absorber is coupled to an adsorption heat pump comprising an adsorber and an evaporator/condenser and wherein there are means for transferring heat of condensation from the condenser of the absorption heat pump alternately to the external load and to the evaporator/condenser of the adsorption heat
70
75
80
85
90
95
100
105
110
115
120
125
4
GB 2 126 706 A 4
pump and means for transferring heat of adsorption and sensible heat from the adsorption heat pump to the generator of the absorption heat pump.
5
7. An apparatus according to claim 5 wherein the means for transferring heat comprise heat exchangers.
8. An apparatus according to either of claims 6
and 7 wherein the adsorber comprises a series of 10 trays one above each other.
9. An apparatus according to any one of claims 6 to 8 which includes a header tank capable of supplying heat transfer fluid to the system.
10. An apparatus according to claim 6
15 substantially as hereinbefore described with reference to the drawing.
Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1984. Published by the Patent Office. 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08225142A GB2126706B (en) | 1982-09-03 | 1982-09-03 | Combined adsorption and absorption heat pump |
| EP83305035A EP0105603A3 (en) | 1982-09-03 | 1983-08-31 | A tandem heat pump |
| NO833154A NO833154L (en) | 1982-09-03 | 1983-09-02 | TANDEM-HEAT. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08225142A GB2126706B (en) | 1982-09-03 | 1982-09-03 | Combined adsorption and absorption heat pump |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2126706A true GB2126706A (en) | 1984-03-28 |
| GB2126706B GB2126706B (en) | 1986-02-05 |
Family
ID=10532673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08225142A Expired GB2126706B (en) | 1982-09-03 | 1982-09-03 | Combined adsorption and absorption heat pump |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0105603A3 (en) |
| GB (1) | GB2126706B (en) |
| NO (1) | NO833154L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5575835A (en) * | 1995-08-11 | 1996-11-19 | W. L. Gore & Associates, Inc. | Apparatus for removing moisture from an environment |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4438427C2 (en) * | 1994-10-27 | 1998-02-12 | Zae Bayern Bayerisches Zentrum Fuer Angewandte Energieforschung Ev | Multi-stage chiller or heat pump |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2088276A (en) * | 1931-12-08 | 1937-07-27 | Siemens Ag | System for the conversion of heat |
| DE2939423A1 (en) * | 1979-09-28 | 1981-04-16 | Alefeld, Georg, Prof.Dr., 8000 München | METHOD FOR OPERATING A HEATING SYSTEM CONTAINING AN ABSORBER HEAT PUMP AND HEATING SYSTEM FOR CARRYING OUT THIS METHOD |
| US4309980A (en) * | 1980-03-07 | 1982-01-12 | Thermal Energy Storage, Inc. | Closed vaporization heat transfer system |
| GB2076523B (en) * | 1980-05-22 | 1984-12-05 | Exxon Research Engineering Co | Absorption heat pump |
| GB2091411B (en) * | 1980-12-05 | 1984-11-28 | Exxon Research Engineering Co | Combined adsorption and absorption heat pumps |
| GB2114730A (en) * | 1982-01-29 | 1983-08-24 | Exxon Research Engineering Co | Absorption heat pump |
-
1982
- 1982-09-03 GB GB08225142A patent/GB2126706B/en not_active Expired
-
1983
- 1983-08-31 EP EP83305035A patent/EP0105603A3/en not_active Withdrawn
- 1983-09-02 NO NO833154A patent/NO833154L/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5575835A (en) * | 1995-08-11 | 1996-11-19 | W. L. Gore & Associates, Inc. | Apparatus for removing moisture from an environment |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0105603A2 (en) | 1984-04-18 |
| NO833154L (en) | 1984-03-05 |
| GB2126706B (en) | 1986-02-05 |
| EP0105603A3 (en) | 1985-08-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU618509B2 (en) | Absorption refrigeration method and apparatus | |
| US5816070A (en) | Enhanced lithium bromide absorption cycle water vapor recompression absorber | |
| KR100214255B1 (en) | Dual temperature heat pump apparatus and system | |
| EP0061888B1 (en) | Staged adsorption/resorption heat pump | |
| US4594856A (en) | Method and device for pumping heat | |
| EP0482738A1 (en) | Combined mechanical refrigeration and absorption refrigeration method and apparaus | |
| JPS59208368A (en) | Heat pump | |
| US5024063A (en) | Branched gax absorption vapor compressor | |
| WO1997040327A1 (en) | Compression absorption heat pump | |
| US4448030A (en) | Combined staged air conditioner and heat store | |
| US5016444A (en) | One-and-a-half effect absorption cycle | |
| US5027616A (en) | Air-cooled absorption type cooling and heating apparatus | |
| US4470269A (en) | Absorption refrigeration system utilizing low temperature heat source | |
| GB2126706A (en) | Combined adsorption and absorption heat pump | |
| GB2076523A (en) | Absorption heat pump | |
| JP2006125713A (en) | Adsorption heating and hot water supply equipment | |
| JPS6036851A (en) | Method of operating two mode heat pump and heat pump | |
| GB2138121A (en) | Sorption heat pumps | |
| JP2002098436A (en) | Refrigeration equipment | |
| GB2114730A (en) | Absorption heat pump | |
| GB2157415A (en) | Coupled heat pumps | |
| JP2018096673A (en) | Absorption type heat exchanging system | |
| JPS59167663A (en) | Recovery device for waste heat from heat pump | |
| JPS6238200Y2 (en) | ||
| JPH0147714B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |