|Publication number||US2794328 A|
|Publication date||Jun 4, 1957|
|Filing date||Jun 29, 1954|
|Priority date||Jun 29, 1954|
|Publication number||US 2794328 A, US 2794328A, US-A-2794328, US2794328 A, US2794328A|
|Inventors||Carlyle S Herrick|
|Original Assignee||Gen Electric|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (24), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
June 4, 1957 C. S. HERRICK VARIABLE TEMPERATURE REFRIGERATION Filed June 29, 1954 3 [)6 Va 77 cprz- Ca r/fy/e 8. fferrick,
His A i-torn ey.
Unite rates Carlyle S. Herrick, Alplaus, N. Y., assignor to General Electric Company, a corporation of New York Application dune 29, 1954, Serial No. 440,623
7 Claims. (Cl. 62-115) This invention relates to refrigeration systems and specifically to a method and apparatus to secure variable temperature levels in such systems.
Refrigeration systems, which are capable of providing automatic variable temperature levels, are desirable in heat pump construction and in commercial and domestic refrigerators. It is desirable that a reverse refrigeration system or heat pump employ a refrigerant mixture whose composition is varied automatically to maintain a constant system capacity over a wide variation in the evaporator temperatures. A conventional refrigeration system, which employs a single refrigerant, will not operate at constant capacity over such temperature variations.
Accordingly, it is an object of my invention to provide a new and improved refrigeration system in which a pair of partly miscible refrigerants are employed.
It is another object of my invention to provide a refrigeration system which circulates a variable mixture of refrigerants in response to the load upon the system.
It is another object of the invention to provide a refrigeration system in which the composition of the refrigerant mixture is determined by the evaporator temperature.
It is a further object of the invention to provide a novel method of refrigeration in which the composition of the refrigerant mixture in the refrigeration system is varied automatically to produce different temperature levels of refrigeration.
In carrying out my invention in one form, the composition of the refrigerant mixture is varied with the evaporator temperature to maintain a constant capacity refrigeration system.
These and various other objects, features and advantages of the invention will be better understood from the following description taken in connection with the accompanying drawing in which:
Fig. l is a schematic view of one form of a refrigeration system which embodies my invention; and
Fig. 2 is a schematic view of a second form of a refrigeration system.
In Fig. 1 of the drawing, a refrigeration system, which may be used in heat pump construction or in commercial or domestic refrigerators and which is indicated generally at 10, comprises a compressor 11 which communicates on its high pressure side with a condenser 12. The condenser 12 is connected to a liquid running receiver 13 in which a pair of partly miscible refrigerants are in a mixture 14 to be circulated through an outlet 15 and an expansion valve 16 to an evaporator 17. The expansion valve 16 is shown to be of a conventional type which is operated by a pressure tube 18 and diaphragm 19. A temperature-operated or thermostatic control valve or sections of capillary tubing could be employed as the expansion device. The evaporator 17 is connected to the inlet or low pressure side of the compressor 11.
A storage receiver 20 is provided in the system to contain an additional supply of the same refrigerants in two separate partly miscible phases or layers 21 and 22. Each atent of these phases 21 and 22 contain both refrigerants in different proportions. The storage receiver 20 is connected to the liquid receiver 13 through a tube 23 with a liquid control valve 24. A vapor space 25 is provided in the top of receiver 20 in which a float 26 may be positioned to actuate valve 24 through a suitable electrical or mechanical connection. A capillary tube 27 connects receiver 20 to outlet 15 between expansion valve 16 and evaporator 17 to circulate slowly a continuous stream of refrigerant phase 21 thereto under gravity head. Tube 23 will replenish the refrigerants in receiver 20 from refrigerant mixture 14 in receiver 13. Vapor space 25 in receiver 2t communicates with the inlet side of the compressor 11 through a tube 28 which is connected to the outlet of evaporator 17. The pressure and composition of the refrigerants in receiver 20 determine the temperature therein which is controlled by evaporator pressure through tube 28. In a reversed refrigeration system or heat pump, the outdoor temperature will regulate indirectly the composition of each of the refrigerant phases 21 and 22.
The pair of refrigerants, which are employed in the refrigeration system, may be miscible at condenser temperature but must be only partly miscible at customary evaporator temperatures. The pair of partly miscible refrigerants forms two separate phases in which each phase is rich in one of the refrigerants and contains also a substantial amount of the second refrigerant. The amount of the second refrigerant in each phase is controlled by the temperature. It is desirable to have a wide variation of phase composition with temperature in the customary evaporator temperature range. The two phases must also have different densities so that separation is possible by gravity. The pair of refrigerants must have difierent volatilities so that the refrigerating capacities of the system may be altered.
The following pairs of refrigerants are given as examples of suitable refrigerant mixtures to be employed in such a variable temperature system: ammonia (NHa) and Freon 12 (CFzClz), ammonia (NI-Ia) and Freon 114 (C2F4C1z), ammonia (NI-I3) and perfluorocyclobutane (C4Fs), ammonia (NHa) and Freon 115 (CzFsCl), ammonia (NI-I3) and perfluoropropane (CaFs), sulfur dioxide (S02) and perfluorocyclobutane (CiFa), methylbromide (CH3B1') and perfluorocyclobutane (C4Fa), methylene chloride (CHzClz) and perfluoropropane (CaFs), ethylchloride (C2H5Cl) and perfluoropropane (CsFs), perfluoropropane (CsFs) and methylbromide (CH3Br), perfluoropropane (CaFa) and methylchloride (CI-IaCl), perfluoropropane (CaFa) and Freon 21 (CHFCIz perfluoropropane (CaFs) and Freon 31 (CHzFCl), perfluorobutane (C4Fm) and Freon 21 (CHFClz), perfluorobutane (Cribs) and methylchloride (CHaCl), perfluorobutane (C4F10) and methylene chloride (CHzClz), perfiuorobutane (C4F1n) and ethylchloride (C2H5Cl), Freon 115 (CzFsCl) and methylene chloride (CHzClz), and Freon 115 (CzFsCl) and sulfur dioxide (S02).
In the operation of the refrigeration system which is shown in Fig. 1 of the drawing, compressor 11 pumps refrigerant mixture 14 through condenser 12 to liquid running receiver 13. Refrigerant mixture 14, which is miscible at condenser temperature, is then circulated through outlet 15, expansion valve 16, and evaporator 17 to the inlet side of compressor 11. The storage receiver 20, in which an additional supply of mixture 14 is con tained in two separate partly miscible phases 21 and 22, is connected to both receiver 13 and outlet 15. The capillary tube 27 from the receiver 20 provides a slow, continuous circulation of phase 21 to outlet 15 to vary the composition of refrigerant mixture 14 in response to the system load. Refrigerant phase 21 is shown to be the operating phase while phase 22 is the storage phase. An increase in the outdoor temperature increases the concentration of the low capacity refrigerant in phase 21 while .a decrease inroutdoor' temperature 111161363565 the concentration of the. high capacity refrigerant .in phase 21. Storage .phase .22 gives :up .oraccepts .fthe neces sary quantities of such refrigerants toaffect these .changes. Thus, the capacity of the refrigeration system remains automatically constant over 'a wide rangeof temperature variations with the addition of only phase 21. Ifit is desired, phase 22 may be the operating phase While phase 21 is the storage phase.
Refrigerant mixture 14 is withdrawn from receiver 13 through tube 23Iand control valve 24 to replenish the refrigerants in receiver 20 which are circulated to the system from phase 21 thereof. Valve24 may be actuated by .any'suitable controls, such as, for example, float 26 which is positioned in receiver 20 and connected mechanically or electrically to valve 24. The withdrawal of a portion ofphase 21 causes the float 26 to be depressed downwardly to open the valve 24. The composition of refrigerant mixture 14 is determined by the system load through the pressure variations of the evaporator. However, the volume of the refrigerant mixture remains constant in the refrigeration system through the addition of refrigerant phase 21 and the corresponding withdrawal of circulating mixture 14.
In Fig. 2 of the drawing, a modified refrigeration system is shown in which anenlarged tubular section 30 is positioned in tube 23 between receivers 13 and 20. The outlet 15 is provided with a heat exchange coil 31 which is positioned within section 30 to cool refrigerant mixture 14 which passes from receiver 13 to storage receiver and to separate mixture 14 into refrigerant phases 21 and 22. The cooling of refrigerant mixture 14 reduces the amount thereof which flashes to vapor at valve 24 to provide better composition control. The refrigeration system of Fig.2 is otherwise similar in structure and operation to the refrigeration system which is disclosed inFig. 1.
As will be apparent to those skilled in the art, the objects of my invention are attained by the use of a refrigerant mixture which is varied with the evaporator temperature to maintain a constant capacity refrigeration 'system.
While other modifications of this inventionand variations of apparatus which may be employed in 'the scope of the invention have not been described,'the invention is intended to include all such .as maybe embraced within the following claims.
What I .claim as new :and desire to secure by Letters Patenttof the United States is:
1. In a refrigeration system including a compressor, a condenser, andan evaporator, a supply of .partlymiscible refrigerants, means tocirculate said supply, .a second supply of partly miscible refrigerants in separate phases, meansto. selectively control the composition of said phases, means connected to said'second supply and said circulating means to supply at least one of said phases to said first mentioned refrigerants to vary the composition thereof, and means to circulate a part of said first refrigerant supply to said second refrigerant supply to replenish the volume thereof.
2. In a refrigeration system including a compressor, a condenser, and an evaporator, a supply of partly miscible refrigerants, means to circulate said supply, a second supply'of partly miscible refrigerants .in separate phases, means connectedto said second supply and said circulating means to supply at least one of said phases to said first refrigerants, and means to circulate a partof said first refrigerant supply to said second refrigerant supply to replenish the volume thereof.
3. In a refrigeration system including a compressor, a condenser, and an evaporator, a pair of liquid receivers, a supply of partly miscible: refrigerants in one of said receivers, means to circulate said supply, a second supply of partly miscible refrigerants in separate phases in said second receiver, means to selectively control the composition of said phases, means connected to said second supply and said circulating means to continuously supply at least one of said phases to said first refrigerants to vary the composition thereof, and means connecting the pair of receivers to circulate a part of said first refrigerant supply so said second receiver.
4. A method of refrigeration which comprises circulating a first supply of partly miscible refrigerants in a refrigeration system, providing a second supply of partly miscible refrigerants in separate phases, circulating one of the phases to the first refrigerant supply to change the composition thereof, and varying the composition of the phases in response to the system load.
5. A method of refrigeration which comprises circulating a first supply of partly miscible refrigerants in a refrigeration system, providing a second supplyof partly miscible refrigerants in separate phases, circulating one of the phases to the first refrigerant supply to change the composition thereof, varying the composition of the phases in response to the system load, and circulating a part ofthe first refrigerant supply to the second refrigerant supply to replenish the volume thereof.
6. A refrigeration system comprising a -:compressor,ta condenser connected to said compressor, a liquid receiver connected to said condensena supply of partly-miscible refrigerants in said receiver, an evaporatorgmeans .conmeeting said receiver to said evaporator, means :connecting said evaporator to said compressor, a vstorage receiver, a supply of ,partly' miscible refrigerants in separate phases within said storage receiver, said storage receiver connected to said liquid receiver and said connecting means between the liquid receiver and the evap-' orator, and means connecting said storage receiver and said connecting means between the evaporator and the compressor to selectively control the composition of the phases within thelstorage receiver. t
7. A refrigeration system comprising ,,a compressor, a condenser connected to said compressor, a liquid receiver connected to said condenser, a supply of partly miscible refrigerants in said 'creceiver, an evaporator, means connecting said receiver to said evaporator, means connecting said evaporator to said=compressor, a storage receiver, a supply of partly miscible refrigerants in separate phases within said storage receiver, and cooling means connecting said storage'receiverand said liquid receiver, means connecting said storage receiver andsaid connecting means between the liquid receiver and the evaporator, and means connecting said storage receiver and said counecting means between the evaporator and the compressor to selectively control the composition of the phases within the storage receiver.
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|U.S. Classification||62/114, 62/513, 62/198, 62/509, 62/502|
|Cooperative Classification||F25B2400/23, F25B2600/2509, F25B2400/16, F25B9/006, F25B2700/04, F25B2400/13|