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Publication numberUS2153695 A
Publication typeGrant
Publication dateApr 11, 1939
Filing dateNov 14, 1933
Priority dateNov 14, 1933
Publication numberUS 2153695 A, US 2153695A, US-A-2153695, US2153695 A, US2153695A
InventorsLawrence A Philipp
Original AssigneeNash Kelvinator Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Air conditioning system
US 2153695 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

April 11, 1939. A. PHILIPP 2,153,695

AIR CONDITIONING SYSTEM Filed Nov. 14, 1953 l /EM i i/ wk ATTORNEY.

Patented Apr. 11, 1939 UNITED STATES AIR CONDITIONING SYSTEM Lawrence A. Philipp, Detroit, Mich assignor, by

.mcsne assignments, to Nash-Kelvinator Corporation, Maryland Detroit, lliicln, a corporation of Application November 14, 1933, Serial No. 697,938

27 Claims.

The present invention relates to refrigeration and more particularly to air conditioning system in which a refrigerating apparatus is utilized for conditioning the air and is based upon the subject matter disclosed and claimed in my copending applications, Serial Nos. 697,169, 697,170 and 697,171 and 697,172,'flled respectively on November 8, 1933.

One of the objects of the present invention to provide a refrigerating apparatus employing a plurality of heat absorbing elements, such as, for example, ,evaporators, and circulating refrigerating medium through the evaporators in such manner that the temperature differential between the same may be attained by providing for different suction pressures at the outlets of the evaporators, and to provide for interconnecting of the outlets of the evaporator soas to at times maintain substantially the same temperature at the evaporators.

Another object of the invention is to control the interconnection of the outlets of the evaporators in response to the relative humidity of the air which is to be conditioned by the evaporators.

Another object of the present invention is to provide a refrigerating system employing a plurality of evaporators which are arranged to be connected with a'plurality of sources of low pressure and which evaporators are at times each individually connected with a source of low pressure and which are at times interconnected with one another and with a plurality of these sources of reduced pressure.

Other and further objects and advantages will be apparent from the following disclosure, reference being had to the accompanying drawing wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawing: I

The figure in the drawing represents more or less diagrammatically my improved refrigerating apparatus and air conditioning system.

Referring to the drawing, I have illustrated the air conditioning system for cooling a room such as an office or a room in a dwelling. The room of the room are shown. A cabinet 24 is disposed within the room 26 and is provided, at the top, with an air inlet opening and an air outlet opening26. A fan 21 driven by a motor 28 causes air to circulate through the cabinet 24. A partition 29 depends from the top wall and extends from the front to the rear of the cabinet for directing air.

'Any form of heat absorbing element may be employed and I have herein illustrated an element comprising evaporators or evaporator sections 36 and 3|, each including a plurality of parallel coils provided with fins 32 for increasing the heat absorbing surface 30. The evaporator 3| has approximately as much heat absorbing surface as evaporator 36. Air from the room 26.

enters the cabinet 24 through the inlet 25 and approximately one half of the air is forced over um through the heat absorbing elements pro vides a plurality of sources of reduced pressure and is herein shown as comprising 'a multiple cylinder compressor 35 having a cylinder 36 and acylinder 31 .This compressor is of the reciproeating type and the cylinder 36 is provided with an inlet 38 and the cylinder 31 is provided with an inlet 39. The inlet 38 also communicates with the crank case of the compressor for withdrawlng gaseous refrigerant therefrom. The outlets for the compressed fluid are connected with one another at 46. The compressor is driven by a motor 42 andreduction gearing may be employed between the motor 42 and compressor 35 if so desired.

Gaseous refrigerant which enters the inlets 38 and 39 is compressed by this compressor, forced into a condenser 43 where it is cooled and liquefied whence it is conducted by a pipe 44 to what is known in the art as a high-side-type float 45. The high-side float forms a receiving chamber 46 for liquid refrigerant and the outlet thereof is controlled by a float actuated valve 41. When a predetermined quantity of liquid refrigerant is delivered to the chamber 46, the float 41 arises and admits the liquid refrigerant toqhe evapor- 56 is provided at the outlet of evaporator 36 and includes a liquid receiving chamber 5| whose outlet is controlled by a float valve 52. When a predetermined quantity of liquid refrigerant is delivered from evaporator 30 by pipe 53 to the chamber 5|, the float valve 52 rises to permit the passing of liquid refrigerant into evaporator 3| through a pipe 54. The outlet of evaporator 3| is connected to the inlet 38 of cylinder 36 by a pipe 55. The high-side-float 56 is also provided with a gaseous refrigerant outlet to which a pipe 51 is connected. Pipe 51 is connected to the chamber 58 of an oil trap 60 and gaseous refrigerant passing from evaporator 38 flows through pipe 51, chamber 58 and through a pipe 6| to the inlet 39 of cylinder 31. An oil outlet of chamber 58 is connected by a pipe 63 with the crank case of compressor and is arranged to deliver entrained oil to the crank case. The outlet of the oil trap is controlled by a float actuated valve 64 which opens the outlet after a predetermined quantity of oil'ls' collected within the chamber 58.

Suction pipes 55 and 51 for evaporator-s 3| and 36 are arranged to be interconnected by pipes 65,- valve 66 and pipe 61. The valve 66 comprises a solenoid core 68 which is arranged to open and close the valve 86. This core 68 when raised by an electro-magnet 68 opens the outlet of the valve 68 to establish connection between the pipe and pipe 51.

Gaseous refrigerant, which is withdrawn from evaporators 38 and 3|, is compressed by the com- .pressor 35, condensed in the condensers 43 and is delivered to float chamber 46. A part of the refrigerant vaporizes in evaporator 38,'the vaporized refrigerant passing through the chamber 5| into pipe 51 whence it is delivered to the inlet 38 of cylinder 31 and, the liquid refrigerant from evaporator 38 flows to the lower part of chamber 5| and through pipe 54 into evaporator 3|. The liquid refrigerant is therein vaporized and the gaseous refrigerant then passes by way of pipe 55 to the inlet 38 of cylinder 36. Moisture from the air condenses on the evaporators 38 and 3| and falls to the bottom of cabinet 24 and is conducted from the cabinet through a drain pipe 18.

The quantity of refrigerant circulated through the refrigerating apparatus and the relative quantities or rate of flow of refrigerant through the evaporators 38 and 3| are governed by the conditions of the air in the room 28. The motor 42 which drives the compressor 35 is cyclically operated and the duration of the phases of operation of the refrigerating apparatus is controlled by the temperature and the relative'humidity of the air in the room 28. It is 'well understood that comfortable temperature varies with the relative humidity of the air. For example, a temperatureof 83 F. of the air at 50% relative humidity is considered a comfortablecondition of the air. In accordance with the present invention, I desire to maintain the air between 82 F. and 84 F. when the relative humidity of the air is approximately 50% or less and for this purpose I provide a thermostat 12 which is connected by a tube 13 to a pressure operated snap switch 14. This switch 14 is arranged to close its contacts when the temperature of the air attains 84 F., and opens its contacts when the temperature is decreased to 82 F. The thermostat bulb 12 and the tube 13 contain a volatile fluid which expands and contracts due to increase and decrease in temperature. When the contacts of the switch 14 are closed a circuit is completed to the motor 42. Switch 14 first closes a relay circuit as follows: main 16, wires Hand 18, switch 14, wire 18, normally closed switch 88; electro-magnet coil 8| and main 82. Coil 8| attracts its armature 83 to cause the same to engage the contact 84 to complete the following motor-circuit: main 16, armature 83, contact 84, wire 85, motor 42 and main 82. The motor being operated, it will cause the compressor 35 to reduce the temperatures of evaporators 38 and 3| and when the temperature of the air at the thermostat 12 decreases to 82 F., the snap switch 14 will be opened to break the circuit through the coil 8| whereby the armature 83 will separate from contact 84 and interrupt the motor circuit.

When the relative humidity of the air in the room is below a predetermined maximum, thesuction lines 51 and 55 are interconnected through the pipes and 61, the valve 68 at this time being open. Under this condition the pressures of the refrigerants in-the evaporators 38 and 3| are substantially the same because either evaporator is connected with both cylinders 36 and 31 of the compressor 35 and consequently the temperatures of both evaporators are substantially the same.

The humidity of the air in the room changes due to changes in the environment and due to the direct adding of moisture to the air and, if the relative humidity of the air is high, a mean temperature of the air at 83 F. would be uncomfortable. In order to rectify this condition, I provide for cooling a portion of the air which passes through cabinet 24 to a lower temperature and for this purpose I utilize an instrument preferably a humidostat 81, which is connected in parallel with the snap switch 14 through wires 88 and 89. This circuit includes a contact 8| and a movable contact 82 which latter is actuated by an arm 83 of the humidostat 81. When the relative humidity of the air is too high, the humidostat 81 actuates its arm 83 to cose contact 82 with contact 8| and thereby completes a circuit to the coil 8|, paralleling the circuit including snap switch 14, as follows: main 16, wires 11 and 88, contacts 82 and 8|, wires 68 and 18, switch 88, coil 8| and main 82. It will be apparent therefore that although the temperature of the air is below 82 F. and. the snap switch 14 is open, a circuit is completed nevertheless through coil 8| to maintain the Inc-- tor 42 operating when the relative humidity oi the air in the room is too high. This condition will cause a prolonged operation of the compressor 42.

In case of a relative high humidity when the air approximates the desired temperature, it is desirable to remove the excess quantity of moisture from the air without materially lowering the temperature of the air. In order to accomplish this, I provide for varying the differential b tween evaporators 38 and 3| by increasing tlze pressure of the refrigerant and likewise the term perature of evaporator 38 and decreasing the pressure of the refrigerant and likewise decreasing the temperature of the eyaportor 3|. In this manner, a portion of the heat absorbing means is reduced considerably below the dew point of the air so as to cause a greater precipitation of moisture from the air at this portion. In order to vary the pressures in evaporators 30 and 3|, I provide for directly connecting evaporator 3| with the cylinder 36 and for directly connecting evaporator 38 with the cylinder 31 by closing the valve 68. The size of the cylinders 36 and 31 are computed relative to the sizes of the evaporators 3| and 38 so that, when these evaporators are directly connected to their respective cylinders, the temperature of evaporator 3| will be lowered below the temperature of evaporator 38. The operation of the valve 68 is governed by the humidostat 81. When the relative humidity of the air in the room is above a predetermined desired maximum, the circuit to the electro-magnet 68 is interrupted so that the valve 68 is closed. During normal operation, that is when the relative humidity of the air is below a predetermined maximum, the humidostat 81 is in a position to close a circuit to the coil 68 so as to cause the core 68 to establish intercommunication between suction pipes 55 and 51. The circuit to the electro-magnet 68 is traced'as follows: main 11, wires 88 and 85, contact 86, movable contact 81, wire 88, electro-magnet 68, wire 88 and main 82. Movable contact 81 is actuated by an arm |8| of the humidostat 81. Thus it is apparent from the foregoing that when the humidity of the air is not above apredetermined maximum, the evaporators 38 and 3| operate at substantially thesame tem- 25 creased sufliciently to actuate the snap switch 8|) pressor 35 and establish individual and independent connections between the respective evaporators and cylinders of the compressor whereby to cause an increased precipitation of moisturefrom the air.

Under some conditions, the relative humidity of the air to be conditioned may be such that the compressor would operate long enough to reduce the temperature of the air to such low degree as to provide an uncomfortably low temperature and, in order to prevent such a condition, 1 provide for stopping the compressor when the tem, perature of the air attains a predetermined low value below which temperature the air would be uncomfortable. For this purpose I provide a thermostat [83 which is connected with the snap switch 50 bya tube I84 Bulb I03 and tube It contain a volatile fluid which expands and con-,

tracts in response to increaseand decrease in temperature. when the temperature of the air in the room is decreased, for example, to 76 F".

the pressure in the bulb I03 and tube H is deto cause its contactsto be separated. Therefore,

so i .be broken by switch 80 and armature 83 will separegardless whether there is a demand for further ,dehumidification through the humidostat 81, the

circuit of coil. 8| through the humidostatf8l will rate from contact 84 to interrupt the motor circuit.

The fan motor 28 operates continuously, it beingconnected to the mains as follows: main 16, wires 11 and I06, motor 28, wires I81 and $9 and main 82.

From the foregoing it will be seen that I ha e provided a refrigerating apparatus which when employed in an air conditioning system, maintains a comfortable temperature under proper humidity conditions and in case the relative humidity is too high, the excess of moisture is removed from the air without materially lowering the. temperature of the air and in case of an extremely high humidity condition, the temperature of the air is lowered but not too cold for comfort or inefiicient operation.

While theform of embodiment of the present invention as herein disclosed constitutes a preferred'form, it is to be understood that other scope of the claims which follow.

I claim: 1. An air conditioning system comprising in combination, a refrigerating apparatusincluding a heat absorbing element about which air to be o d e is i cu ated mean c ne t d wit t e emnt for usin e ti m di m to c cu at ih eih' ou a econd h a sheathi me a ou whi h 'a o e s m t es i ulated. a s delineate w h he eco d do:

mer t for causing refrigerating medium to circus circulate therethrough, a secondheat absorbing saw sb i w i h s t mama' forms might be adopted, all coming within the.

circulated, means connected with the second element for causing refrigerating medium to circulate therethrough, means for controlling the circulating means for maintaining the air between predetermined high and low temperature limits, and means responsive to the humidity of the air to be conditioned for varying the circulation of refrigerating medium by first circulating means through the first heat absorbing element.

3. An air conditioning system comprising in combination, a refrigerating apparatus including a heat absorbing element about which air to be conditioned is circulated, means connected with the element for causing refrigerating medium to circulate therethrough, a second heat absorbing element about which air to be conditioned is circulated, means connected with the second element for causing refrigerating medium to circulate therethrough, means for controlling the circulating means for maintaining the air between predeternnned high and low temperature limits, and means responsive'to the humidity of the air to be conditioned for increasing the circulation of refrigerating medium by the first circulating 'means' through the first heat absorbing element and for impeding the circulation of refrigerating medium by the second circulating means through the second heat absorbing element.

4. An air conditioning system comprising in combination, a refrigerating apparatus including a heat absorbing element about which air to be conditioned is circulated, means connected with the element for causing refrigerating medium to circulate therethrough, a second heat absorbing element about which air to be conditioned is circulated, means connected with the second element for causing refrigerating medium to circulate therethrough, a by-pass for refrigerating medium between said elements, and means resnonsive to the relative humidity of the air to be conditioned for controlling the flow of refrigerating medium through said by-pass and for controlling the quantity of refrigerating medium circulated by both circulating means.

5. An air conditioning system comprising in combination, a refrigerating apparatus including a heat absorbing element about which air to be conditioned is circulated, means connected with the element for causing refrigerating medium to circulate therethrough, a second heat," absorbing element about which air to be conditioned is circulated, means connected with the secondelemansion. a r fr g ra ng easternmosn marsh: bgg lwhieh'air is ee'scadi es is ci cula e a emnressor for wi hdrawing us 0118 r f a m t su ers ar, a Second e p rst ab ut hi a r be cond ned i ci cula a s bed t le ram?! hastensmsswit from the s 1 eva orator. condensin be the com- P 7IS we mphasi a for irik med e ween sa e va orat ra id the be conditioned for controlling the flow of refrigerating medium through the by-pass.

7. An air conditioning system comprising in combination, a refrigerating apparatus including an evaporator about which air to be conditioned is circulated, a compressor for withdrawing gaseous refrigerant from the evaporator, a second evaporator about which air to be conditioned is circulated, a second compressor for withdrawing gaseous refrigerant from the second evaporator, condensing means disposed between the vcompressors and evaporators, a by-pass for refrigerating medium interconnecting the outlets of said evaporators, and means responsive to the humidity of the air to be conditioned for controlling the flow of refrigerating medium through the by- D 85 8. An air: conditioning system comprising in combination, a, refrigerating apparatus including an evaporator about which air to be conditioned is circulated, a compressor for withdrawing gaseous refrigerant from the evaporator, a second evaporator about which air to be conditioned is circulated, a second compressor for withdrawing gaseous refrigerant from the second evaporator, condensing means disposed between the compressors 'and evaporators, a by-pass' for refrigerating medium between said evaporators, and means responsive to the humidity of the air to be conditioned for controlling the flow of refrigerating medium through the by-pass and for controlling the quantity of refrigerant circulated by said compressors.

9. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of heat absorbing elements, a plurality of refrigerant circulating means connected with the heat absorbing elements, and means responsive to the relative humidity of the air to be conditioned for causing one of said circulating means to increase its effectiveness in circulating refrigerant through one of said elements.

10. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of heat absorbing elements, a plurality of refrigerant circulating means connected with the heat absorbing elements, and means responsiveto the relative humidity of the air to be condition'edfor causing one of said circulating means to increase its effectiveness in circulating refrigerant through one of said elements,vand for causing another of said circulating means to impede its effectiveness in circulating refrigerant through the first mentioned element.

11. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of heat absorbing elements, a plurality of refrigerant circulating means connected with the heat absorbing elements, and means for causing one of said circulating means'to increase its effectiveness in circulatingrefrigerant through one of said elements and for controlling the 'quantity of refrigerant circulated ,byisaid plurality "of circulating meansfsaid second means "being ret'ioned; 1.11 1- 7:

sponsive to the humidity of air to be "condi--- 12. An air; conditioning system comprising in 1 combination; a refrigerating apparatus including Y a plurality ofgevaporatorsaboutswhich air'to be: conditioned is circulated, meansfonwithdrawing. I gaseous refrigerantfrom said. evaporators and for compressingrxand' condensing: the: same and for forcing the, condense l refrigerant into. the era-pe rators,. said means-having a plurality; of suction 1 It: inl st ond tso nect m the ,outlet of one of;--.;

said evaporators to one of said inlets, a conduit connecting the outlet of another of said evaporators to another of said inlets, a conduit connecting one of said evaporators with both of said inlets, valve means for. controlling the flow of refrigerant through said latter conduit, and

means responsive to the relative humidity of the air to be conditioned for controlling said valve means.

. 13. An air conditioning system comprisingin I combination, a refrigerating apparatus including evaporators with the inlets of said means, valve controlled means for varying the suction effect atone of the inlets on one of saidevaporators, and means responsive to the relative humidity of the air to be conditioned for controlling said valve means.

14. An air conditioning system comprising in combination, a refrigerating apparatus including aplurality of evaporators about which air to be conditioned is circulated, means for withdrawing gaseous refrigerant from said evaporators and for c compressing and condensing the same andfor forcing the condensed refrigerant into the evaporators, said means having a plurality of suction inlets, conduits connecting the outlets of said evaporators with the inlets of said means, means for relatively varying the quantities of gaseous refrigerant withdrawn from said evaporators including valve means for controlling the flow through the conduits to said inlets, and means responsive to the relative humidity of the air to be conditioned for controlling said valve means.

15. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of evaporators about which air to be conditioned is circulated, means for withdrawing gaseous refrigerant from said. evaporators and for compressing and condensing the same and for forcing the condensed refrigerant into the evaporators, said means having a plurality of suction inlets, conduits connecting the outlets of said evaporators with the inlets of said means, means for relatively varying the quantities of gaseous refrigerant withdrawn from said evaporators including valve means for controlling the flow through the conduits to said inlets, and means responsive to the relative humidity of the air to be conditioned for controlling said valve means and for controlling the quantity of refrigerant circulated by first mentioned means.

16. An air conditioning system comprising in combination, a refrigerating apparatus including ment, the main function of which second element point,-;means'.for causing refrigerating medium to circulatethrough the first heat absorbingele- H ment,'-:,second means for causing refrigerating medium. .to. .circulate through .the second iheat absorbing element and means for controlling'the. quantity. of refrigerant circulated through :from

said heat ,absorbing elements and for relatively varying the; rate of flow. of refrigerant; through the said, elements, said last. mentioned means a be ing responsive to the relative humidity of the air to be conditioned.

17. In an air conditioning system, a refrigerating apparatus comprising in combination, a

heat absorber, means for circulating refrigerant through said heat absorber, a second heat absorber, second means for circulating refrigerant through the second heat absorber, each of the circulating means including a supply conduit for delivering refrigerant from the said means to the absorber and a return conduit for delivering refrigerant from the absorber to the said means, a conduit interconnecting the return conduits,

and means for controlling the flow of refrigerant 'a conduit interconnecting the return conduits,

and means responsive to a psychrometric condition of medium cooled for controlling the flow of refrigerant through the interconnecting conduit.

19. In an air conditioning system, a refrigerating apparatus comprising in combination, a heat absorber, means for circulating refrigerant through said heat absorber, a second heat absorber, second means for circulating refrigerant through the second heat absorber, each of the circulating means including a supply conduit for delivering refrigerant from the said means to the absorber and a return conduit for delivering refrigerant from the absorber to the said means, a conduit interconnecting the return conduits, a valve for controlling the flow of refrigerant through the interconnecting conduit, and means responsive to a psychrometric condition of medium cooled for controlling the valve. 1

20. In an air conditioning system, a refrigerating apparatus comprising in combination, a heat absorber, means for circulating refrigerant through said heat absorber for maintaining said absorber at a certain temperature, a second heat absorber, second means for circulating refrigerant through the second heat absorber for maintaining the second heat absorber at a diiferent temperature, means for interconnecting the first and second circulating means for changing the differential in temperature between the heat absorbers, and means for controlling the interconnecting means.

21. In an air conditioning system, a refrigerating apparatus comprising in combination, an evaporator, means for circulating volatile refrigerant through the evaporator for maintaining the evaporator at a certain temperature, a second evaporator, second means for circulating volatile refrigerant through the second evaporator for maintaining the second evaporator at a difierent temperature, means for interconnecting the first and second circulating means for changing the differential in temperature between the evaporators, and'means for controlling the interconnecting means.

22. In .an air conditioning system, a refrigerating apparatus comprising in combination, an

evaporator, means for circulating volatile refrigerant through the evaporator for maintaining the evaporator at a certain temperature, a second evaporator, second means for circulating volatile refrigerant through the second evaporator for maintaining the second evaporator at a different temperature, a conduit for interconnecting the first and second circulating means for changing the differential in temperature between, the evaporators, and means for controlling the flow of refrigerant through the conduit.

23. In an air conditioning system, a refrigerating apparatus comprising in combination, an evaporator, means for circulating volatile refrigerant through the evaporator for maintaining the evaporator at a certain temperature, a second evaporator, second means for circulating volatile refrigerant through the second evaporator for maintaining the second evaporator at a different temperature, a conduit interconnecting the circulating means for changing the differential in temperature between the evaporators, a valve for controlling the flow of refrigerant through the conduit, and means responsive to a psychrometric condition of medium cooled for controlling the valve,

24. In an air conditioning system, a refrigerating apparatus comprising in combination, a heat absorber, means for circulating refrigerant through said heat absorber for maintaining said absorber at a certain temperature, a second heat absorber, second means for circulating refrigerant through the second heat absorber for maintaining the second heat absorber at a different temperature, said heat absorbers being adapted to cool a common medium, and means responsive to a psychrometn'c condition of the medium cooled by said absorbers forchanging the differential in temperature between said absorbers.

25. In .an air conditioning system, a refrigerating apparatus comprising in combination, a heat absorber, means for circulating refrigerant through said heat absorber for maintaining said absorber at a certain temperature, a second heat absorber, second means for circulating refrigerant through the second heat absorber for maintaining the second heat absorber at a different temperature, said heat absorbers being adapted to'cool a common medium, a conduit interconnecting said first and second elements, and means responsive to a psychrometric condition of the medium cooled for controlling the flow of refrigerant through the conduit.

26. Refrigerating apparatus comprising heat absorbing means, refrigerant circulating means having an outlet and two inlets, conduit means associated with said heat absorbing means and said outlet, two additional conduits associated with said heat absorbing means and said two inlets, valve means for controlling communication between said two additional conduits and humidostatic means for controlling said valve means.

2'7. Refrigerating apparatus comprising heat absorbing means, refrigerant circulating means having an outlet and two inlets, conduit means associated with said heat absorbing means and said outlet, two additional conduits associated with said heat absorbing means and said two inlets, valve means for controlling communication between said two additional conduits and electromagnetic means for controlling said valve means.

LAWRENCE A. PHILIPP.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US6553778 *Jan 16, 2001Apr 29, 2003Emerson Electric Co.Multi-stage refrigeration system
Classifications
U.S. Classification62/198, 62/176.6, 62/196.2, 62/205, 236/44.00R, 62/193, 62/419, 62/208, 62/468, 62/220
International ClassificationF24F3/14
Cooperative ClassificationF24F3/1405, F25B2400/075
European ClassificationF24F3/14A