US2282878A - Air conditioning system - Google Patents

Description

y 1942- A. B. NEWTON 2,282,878

AIR CONDITIONING SYSTEM Filed May 6, 1938 3 Sheets-Sheet 1 I87 Ho Zhwmtor attorney May 12, 1942. A. B. NEWTON AIR CONDITIONING SYSTEM Filed May 6, 1958 3 Sheets-Sheet 2 m m w w R m I T A m 4 R m 3 m .H m k flfl w w m m ,7 A J n. J J

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AIR CONDITIONING SYSTEM Filed-May 6, 1968 5 Sheets-Sheet 3 Snnentor attorney AlwinlBa Newihmm Patented May 12, 1942 AIR CONDITIONING SYSTEM Alwin B. Newton, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application May 6, 1938, Serial-No. 206,411

30 Claims.

This invention relates in general to air conditioning and is more particularly concerned with automatic controls therefor.

The primary object of this invention is to provide an air conditioning system which operates automatically to heat a conditioned space during the heating season, and to cool and dehumidify' the space in a manner to maintain proper temperature and humidity conditions during the cooling season.

More specifically it is an object of this invention to provide a heating and cooling system for a space which consists of a refrigeration system operating on a normal cycle for cooling the space, and which operates on a reversed cycle for heating the space.

In the air conditioning art it is desirable to utilize direct expansion cooling coils in a conditioner for cooling the air being passed to the space, as these coils are very compact and efficient. In larger systems it is desirable to utilize instead of a single cooling coil, a direct expan-' sion typ heat exchanger which is formed of a plurality of parallel passes, for thereby decreasing the pressure drop. Direct expansion coils of this type present a problem of distributing the liquid refrigerant equally to the various passes,

for if the refrigerant is not equally distributed,

either some of the passes will become flooded, and permit the flow of liquid refrigerant to the compressor, or the expansion valve will become closed for preventing flow of refrigerant to all of the passes. In order to distribute refrigerant equally to the various passes it has become common to utilize distributorv devices consisting of restricted inlet orifices for each pass. This arrangement is quite satisfactory for coils which operate only as evaporators. In reversible cycle systems it is desirable to use a single heat exchanger in the air stream as an evaporator during the cooling cycle and as a condenser during the heating cycle. When the heat exchanger is operating as a condenser, the restrictprs used for distributing the liquid refrigerant when the heat exchanger operates as an evaporator are unnecessary, and in fact are undesirable as they create an additional pressure drop within the system. It is an object of this invention to provide a distributor device for a multiple pass heat exchanger which acts to distribute properly the liquid refrigerant to the various passes when the heat exchanger is operating as an evaporator, and which automatically permits by-passing of refrigerant around the distributor restrictions when the heat exchanger is operating as a condenser.

Another object is the provision of a distributor device for a multiple pass unit which utilizes the velocity of the liquid refrigerant leaving the expansion valve for aiding in the distribution of the liquid refrigerant to the various passes.

It is common to utilize valves for changing the direction of flow of refrigerant through a reversible cycle system for reversing the operation of the system. These valves must necessarily be sufficiently large to handle gaseous refrigerant and due to the high pressures involved these valves require considerable power for changing from one position to another. It is a further object of this I invention to provide a reversible cycle system with change-over valves which are operated from one position to another by the pressures within the system, thereby providing for convenient control of the system operation.

A still further object of this invention is the provision of a reversible cycle system of the type which utilizes a single heat exchanger for dissipating heat during the cooling cycle, and for absorbing heat during the heating cycle, with a control arrangement for varying the supplyof water or other heat exchange medium to this heat exchanger in accordance with the cooling and heating loads on the system, to thereby supply just the proper amount of heat exchange medium to meet the needs of the system, thus reducing operating cosm thereof.

Another object of this invention is the provision of a system of the general type with a con trol arrangement for automatically controlling the supply of heat exchange medium in accordance with the demand therefor, and which places the system out of operation when the demand for heat exchange medium varies to a predetermined value.

Still another object of this invention is the provision of a control arrangement for an air conditioning system which maintains proper temperature and humidity conditions within a space by placing a cooling device into and out of operation automatic reversible cycle air conditioning sysgem embodying the novel features of my invenion,

Figure 2 is an elevation in section of one of the refrigerant pressure operated three-way changeover valves, 7

Figure 3 is an'elevation in section showing the expansion valve and distributor arrangement for the direct expansion cooling coils, and

Figure 4 is a view similar to Figure 1 showing a modified piping arrangement for the system.

Referring to Figure 1, reference character! indicates an air conditioning chamber having a fresh air inlet 2, and a return air inlet .3 which communicates with a space to be conditioned 4. The discharge end of the chamber l is connected in opposition and the vertical position assumed by the connecting member I6 is an indication of r the degree of superheat of the refrigerant at the fitting 2|. w

to a fan which acts to draw air through the chamber I and discharge it through suitable duct means into the space 4. Located within the chamber I is a heat exchange device generally indicated as 6, this heat exchange device bein adapted to operate as an evaporator for cooling the space, or as a condenser for heating the,

space. The heat exchange device 6 preferably is formed of a plurality of separate cooling coils or refrigerant passes I, 8, 9, and III. The right hand ends of these coils are connectedto a suitable header ll while the left hand ends of these coils are connected to a combined expansion valve and distributor device indicated as l2.

.Referring now to Figure 3, this figure indicates the construction of the combined expansion valve and distributor device l2. Referring to the expansion valve portion of this device this valve may be of the same type shown in my copending application Serial No. 192,818, filed February 26,

1938. This expansion valve 'may comprise a -a connecting member l6. The diaphragm or bellows I4 is sealed to the lower surface of the diaphragm casing l3 and the lower end thereof is closed by means of a cup member l1. The bellows I5 is similarly sealed to the upper end of casing l3, and its open end is closed by means of a cup member 18. Both the bellows l4 and the bellows l5 are sealed as by soldering to the member l6 so as to provide a unitary fluid tight device. The cup member 11 is provided with a fitting 19 which is connected by a pipe 20 to a fitting 2| located on the header H. A passage 22 is provided within the fitting 19 for placing the interior of the bellows 14 into communication with the interior of header H. The pressure within bellows I4 is therefore equal to the pressure within'this header. Also located within the fitting 2| is a thermostatic bulb 23 which is connected to a capillary tube 24 located within the pipe 29, this tube 24 being attached to the fitting l9 in a manner to communicate with a passage 25 in this fitting. This passage 25 is connected by means of a coiled tube 26 located within the bellows l4 to the interior of the bellows I5. The

bulb 23 contains a suitable volatile fill which preferably is the same as the refrigerant used in the system. The arrangement just described therefore will cause a pressure to exist within ,the bellows l5 which is indicative of the temperature in the header ll, while the pressure with the bellows I4 is equal to the pressure within said header. 7 4

Connected to the member I6 is a rod 21 which extends upwardly through the cup member l8, this rod being threaded at its upper end as 29 which is supported by means of a spring retainer 38. A sealing bellows 3| is provided for within the header II the bellows l4 will expand and, the bellows l5 will contract, while upon an increase in temperature at bulb 23 the pressure expansion of this bellows and contraction of the bellows I 4.

The bellows l4 and therefore act The member I 6 is provided with a pin 32 which an opening 34 into the valve chamber 35. This lever is pivoted to the. valve chamber casing at 36 and carries a valve member 31 cooperating with a valve port 38 located in a nipple 39. A spring 40 is provided for urging the lever 33 in a direction tending to maintain the valve member amount of superheat of the refrigerant leaving the coils 1, 8, 9, and II! should increase, the pressure within bellows l5 will increase; this'causing downward movement of the member I6, and'due to engagement of pin 32 with lever 33 the valve member 31 will be moved away from port 38 to increase the supply of liquid refrigerant to the coils. Conversely upon decrease in the amount of superheat, the member 16 will move downwardly, thereby permitting valve member 31 to approach port 38 under the action of spring 48. By adjusting the-nut 28 any desired degree of superheat may be maintained.

Referring now to the distributor device 42 this device consists of a member 43 having a chamber noted that the nipple 39 is formed to provide a venturi and that the chamber 44 is in direct alignment-with the valve port 38, so that the stream of liquid passing through the valve is discharged'into the chamber 44 at high velocity. This high velocity discharge of refrigerant into the chamber 44 causes the liquid refrigerant to become a homogeneous mixture of liquid and gas within this chamber and to. pass through the restricted passages 45 into the coils 1, 8, 9, and I0. Due to this action of refrigerant within the chamber 44, both the gaseous and liquid refrigerant will be divided equally between the various coils. This arrangement'therefore provides for the passing of the proper amount of liquid refrigerant to each coil and thereby prevents the flooding of one coil and the starving of another.

Each of the passages or connections 46 communicate through a passage 41 with a chamber 48 formed between the member and a cap member 49. This chamber 48 is connected to a discharge connection 50. Each of these passages I shown and carrying a nut 28 engaging a spring w ithin bellows I5 will increase thereby causing", 4

41 is also provided with a ball valve member 5| which is urged against its seat by means of a spring 52 located within a recess 53 located within the cover member 49. The purpose of the passages 41 and the valve members 5| is to permit the passag of refrigerant from the coils 1, 8, 9, and HI into the outlet connection 50 when the coils 1, 8, 9, and H) are acting as condensers.

This arrangement avoids the necessity of pass-' device 42 will become apparent as this description proceeds.

Reference character 55 indicates a compressor which may be driven by means of an internal combustion engine 56 through any suitable drive means such as pulleys 51 and 58 over which run belts 59. The discharge of the compressor 55 is connected by means of a discharge line 60' and pipes GI and 62 to three- way valves 63 and 64,

respectively. Other ports of these three-way valves are connected by pipes 65 and 66 to a suction line 6' I leading to the inlet of the compressor 55.

Referring now to Figure 2 this figure shows a preferred construction for the three- way valves 63 and 64. Each of these valves may consist of a valve casing 68 containing a transverse partition 69 having a valve port 18 therein. v This valve port III places the passages II and I2 within the casing 68 into communication. The lower end of the casing 68 is provided with a cap member 73 having therein an inlet passage I4 and providing a valve port 'I5-which is in alignment with the port 18. Reference character I6 indicates a valve member which is adapted selectively tocover the valve port I8 or the valve port I5. This valve member is slidably mounted upon a valve stem H which is joined to a piston I8 which in turn is fitted into a suitable cylinder or guide formed in the casing 68 above the valve port I0. The valve stem 11 at its lower end is secured to a guide member I9 located in passage 14 below the valve port I5. The valve stem 11 is also threaded at 88 to receive the nut 8| which abuts spring 82, the lower end of this spring in turn abutting the valve member I6. The spring 82 therefore serves to urge the valve member I6 downwardly on the stem I1 and against the guide member I9 for normally causing movement of the valve member 16 with movements of the stem 11. A second spring 83 is located above the valve port I8 and serves to urge the valve stem upwardly for biasing the valve member 16 against the valve port I0.

Mounted above the valve casing 68 is adiaphragm 84 which may be formed of any suitable flexible material which is resistant to the refrigerant utilized in the system. This diaphragm.

is covered by means of a cap member 85 which is secured to the valve casing 68. this cap member being formed to provide a chamber 86 communicating with a port 81 leading to a valve port 88 which in turn communicates through apassage 89 with the passage -I2. A valve member 96 cooperates with the port 88 and is operated by means of a plunger 9I of a solenoid 92. The diaphragm 84 is secured to the valve stem 11 by means of a nipple 93, this nipple having a passage 94 communicating with a passage 95in the valve stem 11. A restriction 96 is located within the passage 95 so as to permit only a restricted flow of refrigerant from the inlet passage I4 through the passages 95 and 94 into the diaphragm chamber 86. If desired, this restriction may be covered with a suitable strainer.

Assiuning that solenoid 92 is deenergized, the valve member 98 will cover the valve port 88 and thus prevent any escape of refrigerant through the passage 89. The passage I4 it will be noted is connected to the discharge side of the compressor and consequently the pressure at the inlet of passage 95 is relatively high. This high pressure refrigerant will pass through the restriction 96 and passages95 and 94 into the diaphragm chamber 86 thus urging the diaphragm 84 downwardly which in turn urges the valve stem 11 and the valve member I6 "downwardly for covering the valve port I5. This will place the passages -II and I2 into communication. Now if the solenoid 92 is energized, the valve member 90 will be withdrawn from the port 88 thus permitting flow of refrigerant from the diaphragm chamber 86 into the passage I2. This passage I2 it will be noted is connected to the inlet of the compressor and consequently the pressure within this passage is relatively low. Due to the action of the restriction 96, refrigerant will pass from the chamber 86 into the passage I2 at a faster rate than the refrigerant will pass from passage 14 into the chamber 86. Consequently the pressure above the diaphragm 84 will be reduced, thus permitting the :spring 83 to move valve stem 11 and the valve member I6 upwardly for uncovering the valve port 15 and covering valve port III. This will place the ports II and 14 into communication. From the description thus far, it should be apparent that the port II is selectively connected to ports 12 or 14 under the control of the solenoid 92. The purpose of this arrangement will becomeapparent as this description proceeds. I

At this time it should be observed that when one of the valves 63 or 64 is in the position shown in Figure 2, wherein'its port I4 is covered by the valve member 16, the port I2 is in communication with the passage 'II and the passage I4 is covered. As pointed out previously, the passage I4 is con-. nected to the discharge side of the compressor while the passage I2 is connected to the inlet or the suction side of the compressor.- If for some reason the discharge pressure of the compressor should become excessive, the valve member I6 will be urged upwardly on the valve stem 11; due to the yielding of a spring 82. This will permit flow of high pressure refrigerant around the valve member I6, through the port I0, and passage 12 to the inlet of the compressor. This arrangement therefore provides for automatic unloading of the compressor when the head pressure becomes excessive, thereby preventing damage to the compressor or other parts of the system. It should be noted that piston I8 is limited in its downward movement by shoulder 18a. This limits the amount that spring 82 may be compressed, and thus provides a definite pressure at which spring 82 will yield for unloading the compressor.

Referring again to Figure 1, the passage II of the three-way valve 63 is connected by a pipe 91 to an evaporator condenser 98 and the corresponding passage of three-way valve 64 is connected by a pipe 99 to the header II of heat exchanger 6. The three way valves 63 and 64 therefore provide for selective communication of the heat exchangers 6 and 98 with either the inlet or outlet of the compressor 55. This arrangement provides for causing the heat exchanger 6 to operate eitheras a condenser or as an evaporator for thereby either cooling or heating the space.

Reference character I88 indicates an auxiliary evaporator which contains a heat exchange coil IIII connected by a pipe I02 to the exhaust manifold I83 of internal combustion engines 56. The coil I III is therefore heated by exhaust gases from engine 56. Located above the coil IOI is a spray pipe I04, and located below the coil I8I is-a sump for collecting refrigerant which has been sprayed over the coil IN. This sump is provided with a float valve I for maintaining at least a predetermined amount of liquid refrigerant therein. This float valve controls the flow of refrigerant into pipe I96 which leads through a check valve I2I,and I22.

an in contact I23 and with an out contact I01 into receiver I08. This receiver in turn is connected by pipe I08 to'the expansion valve I2 for heat exchanger 6 and to the expansion valve I I for the evaporator-condenser 88. This evaporator-condenser is also'connected by pipe III' changer 6.

The solenoids of the three- way valves 63 and 64 are controlled by means of a relay I II which includes a relay coil I I8 which operates through a suitable armature a series of switch arms II8, I20, The switch arm I I8 cooperates with I24, which the switch arm I20 cooperates with an in contact I and anfout" contact I26. The

switch arm I2I cooperates with an in" contact I21, and switch arm I22 cooperates with an in contact I28. When the relay coil I I8 is energized in a manner which will be described hereinafter, the switch arms H8, I20, HI, and I22 will be brought into engagement with their respective in contacts. However, when relay coil H8 is deenergized, the switch arms will disengage their respective in contacts and the switch arms I I8 and I20 will engage the out contacts I24 and I26, respectively.

Reference character I indicates a step-down transformer having a primary I3I connected across line wires I32 and I33. The secondary I34 of the transformer I30 has one terminal connected to the switch arm I20 by a wire I35, and its other terminal is connected by wires I36 and I31 to the solenoids of three- way valves 63 and 64. The in contact I25 of the relay I I1 is connected by wire I38 to thesolenoid of three-way valve 64, and the out contact I26 is connected by wire I38 to the solenoid of three-way valve 63. By this arrangement it will be apparent that when relay coil H8 is energized, 'the switch arm I20 will engage contact I25 and energize the solenoid of three-way valve 64 as follows: transformer secondary I34, wire I35, switch arm I20, contact I25, wire I38, solenoid of valve 64, and wire I36 to the other side of transformer secondary I34. At this time therefore the solenoid of valve 64 will be energized while the solenoid of valve 63 will be deenergized. Similarly when the relay coil I II is deenergized, the switch arm I20 will engage contact I2'I for energizing the solenoid of three-way valve 63 while deenergizing the solenoid of threeway valve 64. It will therefore be seen that whenever the solenoid of valve 63 is energized, the solenoid of valve 64 is deenergized and vice versa.

During the cooling season the relay coil 8 of the relay I I1 will be deenergized, this causing engagement of switch arm I20 with contact I2I for energizing the solenoid of three-way valve 63 while deenergizing the solenoid of valve 64. This will cause the valve member I6 of the three-way valve 63 to cover its port I0 thus placing its passages II and I4 into communication. The threeway valve 64 however will assume the position shown in Figure 2 wherein the passages II and I2 are placed into communication. For these positions of the three- way valves 63 and 64, refrigerant will flow from the compressor 55 through discharge line 60 and pipe 6| into three-way valve 63, passing from this valve through pipe 81 into the evaporator-condenser 88. At this time this I, 8, 8, and I0 wherein it evaporates for cooling the air passing through chamber I. From the header II, the evaporated refrigerant will flow through pipe 88 and through the three-way valve 64 to pipe 65 and through suction line 61 back to the compressor 55. At this time it will be apparent that the heat exchanger 86 will operate as a condenser and the heat exchanger 6 in the conditioning chamber I will act as an evaporator for cooling and dehumidifying the air passing to the space 4.

During the heating season the relay coil II8 of relay I I1 will be energized for causing engagement of the switch arm I20 with contact I25, thus energizing the solenoid of three-way valve 64 and deenergizing the solenoid of three-way valve 63. This will cause the solenoid valve 63 to assume the position shown in Figure 2 wherein the passages II and I2 are in communication, and will cause the three-way valve 64 to assume a position in which the passages II and I4 are in communication. With the valves 63 and 64 in these positions,

refrigerant will flow from the compressor through discharge line 60 and pipe 62 into the three-way valve 64and then through pipe 88 and header II to the coils I, 8, 8, and I0. These coils will now act as condensers for condensing the refrigerant and delivering up its latent heat of evaporation to the air being heated. The liquefied refrigerant will flow from each of these coils into the respective passages 46 of the distributor device 42, and

will pass through passages 41 and check valves 5| into the chamber 48 from which it passes through pipe I I6 to the inlet of pump II4.

This refrigerant is then forced into the spray pipe I 04 by the pump I I4 and is sprayed over the pipe IOI which is heated by exhaust gases from the engine 56. This will re-evaporate a portion of the sprayed refrigerant and this re-evaporated portion will pass from the auxiliary evaporator through pipe I40 and to the pipe 88 and back through the coils I, 8, 8, and I0 for transferring the heat of the exhaust gases to the air passing through the conditioning chamber I. The unevaporated portion of the sprayed refrigerant in the auxiliary evaporator I00 collects in the sump of this device and is recirculated through pipe I I5 and pump II4 for being again sprayed over the coil IIII. This arrangement. provides for very eflicient heat transfer between exhaust gases of the engine and the high pressure refrigerant in the system.

Liquid refrigerant will also pass from the auxiliary evaporator I00 through pipe I06 and check valve I0'I into the receiver I08 andwill pass from this receiver through pipe I08 to the expansion.

reversing the operation of a refrigeration system under the control of therelay I". When this relay H1 is energized-the heat exchanger 6 in the conditioning chamber will operate as a. condenser for heating the air and the heat exchanger 98 will operate as an evaporator for absorbing heat from an outside source. -Also at this time the exhaust heat from the engine will be transferred to the exchanger 6 due to the action of the auxiliary evaporator I00. When the relay I I1 is deenergized however, the heat exchanger 6 will operate as an evaporator for cooling the air passing through chamber I and the heat exchanger 98 will operate as a condenser for dissipating the heat absorbed by the heat exchanger 6.

Referring now to the internal combustion engine 56 this engine may be of any desired type and is shown as including an intake manifold I, a throttle valve I42, a generator I43, and a starting motor I44. Reference character I45 indicates a relay for controlling the starting motor I44 in a.

manner to cause operation of the starting motor for starting the engine when the ignition circuit is closed, and for deenergizing the starting motor after the engine has started. This relay I45 may be of any desired type and if desired may be of the type shown and described in Patent No. 1,773,913 issued to L. K. Loehr et al. on August 26, 1930. This starting relay is so arranged that upon the closing of a control circuit, a magnetic device is energized which causes closing of a switch in the starter circuit. For this purpose the relay I45 is connected to a storage battery .I46 by means of wires I41 and I48, and by a wire I49 to the starting motor I44. This relay I45 is also provided with a lockout circuit for preventing energization of the starting motor I43 when the engine is in operation as evidenced by operation of the generator I43. For this purpose the relay I45 is connected by wires I50 and I5I to the generator I43. The wire I5I is additionally connected to the storage battery I46 through a reverse current relay I43a for charging said storage battery. The storage battery I46 is additionally connected by wire I52, switch arm I52a, wire I53, and wire I53a to the contact I28 of relay II1, and the cooperating switch arm I22 is connected by wires I54 and I55 to the control terminal of the relay I43. This wire I55 is also connected to the spark coil I56. By this arrangement, when the relay H1 is energized the spark coil I56 will be energized and also the starting relay I45 will be energized for causing operation of the starting motor. This in turn will cause starting of the engine 56 and the relay I45 in response to this starting of the engine will deenergize the starting motor I44 and maintain this motor deenergized so long as the engine is in operation. When the relay I45 and spark coil I56 are deenergized however, as by deenergization of relay I I1, the engine will stop.

The throttle valve I42 of the engine 56 may be positioned by means of a proportioning motor I51. This motor may be of any desired type and preferably is of the type shown and described in Patent No. 2,028,110 issued to D. G. Taylor on January 14, 1936. This type of motor is adapted to be controlled by means of one or more potentiometer controllers and will assume intermediate positions corresponding to the position of the slider of a potentiometer controller upon its resistance.

-Proportioning motor I51 is arranged to be controlled by means of a winter thermostat I58 and a summer thermostatl59. Referring to the Winter thermostat I58, this may be of any desired type and is shown as comprising a bellows I60 which is connected by a capillary tube I 6| to a control bulb I62 located within the return air inlet 3. The bellows 60 may actuate a bell crank lever I63 having an actuating arm I64 and a control arm or slider I65 which cooperates with a resistance I66 to form a control potentiometer for motor I51. The bulb I62, tube I6I, and bellows I60 are charged with a suitable volatile fill for causing the pressure within bellows I60 to in rease upon increase in return air or space temperature. Thus as the space temperature increases, the pressure within bellows I60 will increase for causing movement of slider I65 to the right across resistance I 66. Upon decrease in temperature however the bellows I60 will contract under the biasing action .01 a spring I61 thu moving slider I65 to the left across resistance I66. This instrument may be so designed and adJusted as tocause the slider I65 to engage the extreme right-hand end of resistance I66 when the space temperature is at 72 F. while engaging the left-hand end of resistance I66 when the space temperature falls to 70 F. The winter thermostat I58 is also provided with an auxiliary switching means for energizing the relay II1 when the space temperature falls below 72 F. This switching means is diagrammatically illustrated as comprising -a mercury switch I68 mounted upon the actuating arm I64 in such a manner that its electrodes are unbridged when the slider I65 engages the right-hand end of resistance I66 while causing these contacts to be bridged whenever the slider I 65 moves away from this extreme right-hand position. The mercury switch I68 is connected in series with the transformer secondary I34 and relay coil II 8 bywires I10, HI, and I12. It will be apparent that when the space temperature is above 72 F., the electrodes of mercury switch I68 will be unbridged thus deenergizing relay 'coil I I8, while when the space temperature is at 72 coil I I8 will be energized.

Referring to the summer thermostat I59, this instrument may be formed similarly to the thermostat I58. It comprises a bellows 3I5, bulb 3I6 located in return air duct 3, and connecting tubing 3". It further includes a slider I 13 operated by bellows 3I5 and which cooperates with a resistance I14 to form a control potentiometer. This instrument may be so designed and adjusted as to cause the slider I13 to engage the righthand end of resistance I14 when the space temperature is at 75 or below while engaging the left-hand end of resistance I 14 when the space temperature rises to 82 F.

Referring now to the connections between the thermostats I58 and I59 and the motor I51, it will be noted that the left-hand end of resistance I66 and the right-hand end of resistance I14 are connected by wires I15, I16, and I11 toterminal B of the proportioning motor I 51, while the righthand end of resistance I66 and the left-hand end of resistance I14 I19, and I to terminal W of motor I51. The slider I65 of thermostat I58 is connected by wire I8I to the contact I23 .of relay H1, and the slider I13 of thermostat I59 is connected by wire I82 to the contact I24. The switch arm II 9 of this relay is connected to terminal R of motor I51 by wire I83.

Referring again to the motor I 51, this motor will operate in a direction for opening the throttle valve I 42 as the resistance between terminals R and B is decreased, and will operate to close the throttle valve I42 as the resistance between or below, the relay are connected by wires I18,

terminals R and W is decreased. With the thermostats I88 and I88 in the positions shown the space temperature is at71 F., which causes the slider I88 of thermostat I58 to engage the center of resistance I88. For this valueof temperature, the switch I88 is tilted so that its elec trodes are bridged, this energizing the relay II1 thus causing the switch arm II8 to engage the contact I23. This, it will be noted, disconnects terminal R of motor I51 from the thermostat I58 and connects this terminal of the motor to the slider I85 of thermostat I58. Due to the slider I88 engaging the center of resistance I58, the resistance connected between terminals R and W and between terminals R and B of the motor are equal. Accordingly the motor I51 has assumed mid-position in which the throttle valve I42 is half open. If the space temperature decreases, the slider I85 will move to the left across resistance I88 thus decreasing the resistance connected between terminals R and B of the motor,

while increasing the resistance connected between terminals R and W. This will cause the motor I51 to rotate in a direction for opening the throttling valve I42 wider thereby increasing the speed of the engine. Upon an increase in space temperature the slider I85.w ill move to the right across resistance I88 for causing motor I51 to move the throttle valve I42 to a further closed position.

When the space temperature rises above 72 F. the electrodes of mercury switch I58 will become unbridged thus deenergizing the relay H1. The resulting engagement of switch arm II9 with contact I24 will completely disconnect the slider I85 of thermostat I58 from the proportioning motor I51, and will connect the potentiometer slider I13 of thermostat I59 to this motor. If the space temperature is below 75 F., the slider I18 of thermostat I59 will engage the ght-hand end of resistance I14 and this will substantial short circuit from terminal R of the motor through wire I83, switch arm II9, contact I24, wire I82, slider I13, wire I18, and Wire I11 to terminal B of the motor thus causing this motor to run to a position in which the throttle omplete a engaged from contact I28, the energizing circuit for the starting relay I48 and the engine ignition willnot be closed through this relay II1.

Consequently the engine 58 will not operate at this time unless placed into operation by the space relative humidity controller I81.

Referring to this humidity controller I81. this controller maybe of any desired type and is shown diagrammatically as comprising a bell crank lever I88 having an arm I88 carrying a mercury switch I88. Attached to the lever I88 valve is wide open. As the space temperature increases above 75' F., the slider I13 will move to the left across resistance I14 and the motor I51 will follow up this movement for moving throttle valve I42 towards closed position.

It should be noted that contact I21 of relay I I1 is connected by a wire I84 to the line wire I88 and the switch arm I2I is connectedby wire I85 to the pump motor H5. This pump motor H5 in turn is connected by a wire I88 to the line wire I32. Thus when the switch arm I2I engages contact I21 the pump motor II 5 will be energized.

From the foregoing description it should be apparent that when the space temperature is above 72 F. the mercury switch I88 of thermostat I58 will be in open position, this causing deenergization-of the relay II1. This will cause the switch arm II9 to engage the contact I24 for placing the summer thermostat I59 in control of the engine-throttle valve. Also due to switch arm I28 engaging contact I25, the solenoid of three-way valve 53 will be energized and the solenoid of three-way valve 54 will be deenergized. This will position these valves in a manner to cause the system to operate on the cooling cycle.

Due to the switch arm I2I being disengaged from contact I21 the pump II5 will not operate at this time. Also due to switch arm I22 being disis a humidity responsive device which may consist of a plurality of strands "I of hair or other moisture responsive material. ,A spring I82 is also provided for biasing the lever I88 in a direction to maintain the strands I8I taut. Uponanincrease in relative humidity, these strands will increase in length this permitting rotation of lever I88 in a direction for tilting the mercury switch I88 to closed position. Upon a decrease 'in relative humidity, the strands I8 I will shrink thus rotating lever I88 for tilting mercury switch I98 to open position. The mercury switch I88 is connected by wires I83 and I94 to the wires I88 and I54 thus placing the switch I88 in parallel relationship with the switch arm-J22 and contact I2I of the relay H1. The humidity contro1ler'I81 may be adjusted in a manner to cause closure of mercury switch 88 only when the relative humidity rises to a predetermined value such as 60%. Thus when the system is operating on the cooling cycle, the engine 58 will remain at rest so long as the relative humidity is below 60%. When this relative humidity rises above this value, closure of the mercury switch I88 will cause closure of the engine starting circuit thereby placing engine 58 into operation. At this time the engine speed will be dependent upon the space temperature. Thus if the space tempera-. ture is at F. or below the engine will be run at high speed for operating the heat exchanger 8 at a lowtemperature for providing maximum dehumidiflcation. This will reduce the space relative humidity relatively quickly thus causing the humidity controller I81 .to stop the engine vide for doing a larger amount of cooling thus preventing the space temperature from becoming excessive. If desired, instead of utilizing a plain type humidity controller as shown, a compensated humidity controller such as shown in my co-pending application Serial No. 199,217, filed March 31, 1938, may be utlized. "This type of humidity controller is automatically adjusted in accordance with space temperature for lowering the control point of the humidity controller upon increase in space temperature. Thus with -a controller of'this type, if the space temperature becomes excessive, the humidity controller will place the compressor into operation even though the space relative humidity has not increased.

If the space temperature should now fall below 72 F. the mercury switch I88 of thermostat I88 will close, this energizing the relay II1. Due to Due to this action, the engine,

the resulting engagement of switch arm II9 with contact I23, the thermostat I58 will be placed in control of the throttle valve motor I51 while the thermostat I59 will be disconnected from this motor. Also due to the switch arm I20 engaging contact I25 the solenoid of three-way valve 64 will be energized and the solenoid of three-way valve 83 will be deenergized. This will cause the valves 83 and 54 to assume positions for causing operation of the system on the heating cycle for heating the space. switch arm I2I with contact I21 will start the refrigerant circulating pump H5, and engagement of switch arm I22 with contact I28 will complete the engine starting circuit thus placing the engine 55 into operation. Thus when the space temperature is above 72 F. the threeway valves 53 and 54 will be in position for operating the system on the cooling cycle, the summer thermostat 59 will be placed in control of the engine throttle valve, and the starting and stopping of the engine will be placed under the control of the humiditycontroller I81. When the space temperature falls below 72 F. the threeway valves 83 and 64 will be positioned for operating the system on the heating cycle, the engine will be placed into operation, the circulating pump II will be placed into operation, and the throttle valve motor I51 will be placed under the control of the winter thermostat I58.

The heat exchanger 98 it will be understood operates as an evaporator during the cooling cycle for absorbing heat from the water passing therethrough, and acts as a condenser during the cooling cycle'for dissipating the heat absorbed from the conditioned space. An additional feature of the present invention lies in a control arrangement for automatically varying the supply of water or other heating and cooling medium to the heat exchanger 98 in accordance with the demand for either heating or cooling. Referring now to the control arrangement, ref- In addition, engagement of erence character I95 indicates a water supply control valve, this valve being connected to the water inlet of the heat exchanger 98 by pipe I96.

The water outlet for the heat exchanger 98 is connected by a pipe I91 to the water jacket of engine 58, and outlet of this water jacket is connected by a pipe I98 to waste. This pipe I98 it will be understood-may return the water to its source if the source of water supply is from a well or pond. If city water is utilized, this pipe I 98 may be connected to a sewer.

The valve I95 is actuated by means of a suitable proportioning motor generally indicated as I99, this motor being under the conjoint control of a winter controller 200, a summer controller 20l, and an engine temperature responsive thermostat 202. Referring to the motor I99, this motor may be of the type shown and described in the Taylor patent and is diagrammatically indicated as comprising a main operating shaft 203 which is driven through a gear train 204 by means of a reversible electric motor indicated as comprising rotors 205 and 206 cooperating with field coils 201 and 208. The rotor 206 and coil 208 form a motor for driving the shaft 203 in one direction, and the rotor 205 and coil 201 form a motor for driving the shaft 203 in the opposite direction. The shaft 203 carries a crank 209 which is connected to the valve stem of valve I95. This shaft also operates "a balancing potentiometer 2I0 comprising a slider 2H and a balancing resistance 2I2. I

Energization of the field coils 201 and 208 is controlled by means of a balancing relay 2|3 which comprises a pair of serially connected relay coils 2 and 2| 5 which actuate through a suitable armature, a switch arm 2I8 cooperating with contacts 2" and 2I8. The switch arm 2|8 is connected by wire 2|9 to the secondary 220 of step-down transformer 22|, the primary 222 of which is connected across the line wire I32 and I33. The other terminal of secondary 220 is connected by wires 223 and 224 to the connected ends of field coils 201 and 208. The contact 2" is connected by wire 225 to the field coil 201, and the contact 2I8 is connected by wire 228 to the field coil 208. In addition the relay coils 2 and 2 I5 are connected in series across the transformer secondary 220 by means of wires M8, 221, 228, 229, 230, 23I, and 223. when the relay coils 2|4 and 2|5 are equally energized, the

switch arm 2|6 will assume mid-position in which it is disengaged from contact 2" and contact 2|8. If the relay coil 2|5 should become energized more highly than coil 2 the switch arm 2|8 will engage contact 2I8 and this will energize the motor field 208 for driving the operating shaft 203 in a direction. for opening the valve I95. If relay coil 2| 4'becomes energized more highly than coil 2| 5, the switch arm 2I6 will engage contact'2l1 for energizing motor field 201 this driving the shaft 203 in a direction for closing valve I95.

Referring to the controller 200, this controller includes a bellows 232fwhich operates a bell crank lever 233 having an actuating arm 234 and a slider 235 which cooperates with resistance.

236to form a control potentiometer. The bellows 232 is connected by a tube 231 to. the pipe 91 adjacent the heat exchanger 98. The actuating arm 234 may be biased against the bellows 232 by means of a spring 238. This spring may be so adjusted as to cause the slider 235 to engage the right-hand end of resistance 238 when the pressure within bellows 232 is below a predetermined value. If Freon is used as the refrigerant in the system, this value may be approximately 116 lbs. per sq.-inch. ,When the pressure within bellows 232 rises to 120 lbs. per sq. inch the bellows will expand against the action of spring 238 for causing the slider 235 to engage the left-hand end of resistance 236. The bellows- 232 may also actuate a second slider 239 cooperating with a resistance 240. This slider 239 is indicatedas being actuated with. slider 235 by means of an insulated connection 24I.

The Winter pressure controller 20I may be formed similarly to the pressure controller 200 and comprises a first slider 242 cooperating with a resistance 243 to form a control potentiometer,

end of this resistance when the pressure risesto 55 lbs. per sq. inch.

Referring to the thermostat 202 this thermostat may be formed similarly to the controllers 200 and 20| and consists of a bellows 250 for operating sliders 25I and 252 which cooperate with resistances 253 and 254, respectively. The bellows 250 is connected by a capillary tube 255 engaging, the left-hand end of resistance 263 when the engine temperature rises to 170 F.

Referring now to the connections between the relay 2I3 and the various controllers it will be noted that the left-hand end of resistance 236, the right-hand end of resistance 243, and the left-hand end of resistance 253 are connected to the relay coil 2I4 by wires 228, 251, 258, 259, and 250. Also the relay coil 2 is connected to'the upper end of the balancing resistance 2I2 by wire 26I and resistance 262. The lower end of balancing resistance 2| I, the right-hand end of resistance 236, the left-hand end of resistance 243, and the right-hand end of resistance 253 are connected to the relay coil 2I5 by wires 229, 230, 264, 265, 266, and 261. The resistances 2I2,

236, 243, and 253 are therefore connected in this exchanger. If the demand for heat increases, the engine speed will be increased this tending to reduce the pressure within heat exchanger 98. This decrease in pressure within heat exchanger 98 will cause movement of the slider 242 to the right across resistance 243. This will have the effect of decreasing the portion of resistance 243 which is connected in parallel with relay coil 2I4, and will/increase the portion of this resistance which is connected in parallel with relay coil 2 I5. This will cause the switch arm 2I6 to engage contact 2" for energizing motor field 201, which rotates shaft 203 in a direction for opening the valve I95 and increasing the supply of water to the heat exchanger 98. This action has the effect of increasing the amount of heat supplied to the reversed cycle of the refrigeration system. As the shaft 203 rotates for opening valve I95, the slider 2 of the balancing potentiometer will move downwardly on resistance 2I2 thereby decreasing the portion of this resistance which is conparallel with the serially connected relay coils across the transformer secondary 220. The junctions of relay coils 2 and 2I5 are connected by wires 268, 269, 210, 21I, 212, 213, and 214 to the sliders 2II, 239, 244, and 252. The resistances 240, 245, and 254 it will be noted are connected to the sliders 235, 242, and 25I, respectively. The sliders 2, 235, 242, and 25I therefore are each connected to the junction of relay coils 2 and 2I5. It will be apparent that this arrangement will cause each of these sliders to divide their respective resistances into one portion which is connected in parallel with relay coil 2, and a second portion which is connected in parallel with the relay coil-2| 5. Thus movement of any of the sliders on their resistances will vary the relative energization of the relay coils 2I4 and 2I5.

With the parts in the positions shown, the system is operatingon the heating cycle. quently the heat exchanger 98 is nowacting as an evaporator and the refrigerant pressure therein is therefore relatively low, this pressureat this time being 52.5 lbs. per sq. inch as indicated by the slider 242 of controller 20I engaging the center of resistance 243. Due to this low pressure the slider 235 of controlled 200 is engaging the right-hand end of resistance 236. Also at this time the engine: temperature is below 160 F. as indicated by the slider 25I engaging the right-hand end of resistance 253. With the slider 235 in the position shown, the slider 239 is engaging the right-hand end of resistance 240 and therefore the entire resistance 240 is connected in series with the slider 235. Due to this resistance being connected in series with slider 235, a very small amount of current will flow through this slider and consequently the position of this slider will have substantially no effect upon the position assumed by motor I99.

Also with the slider 25I of thermostat 202 in the position shown, the entire resistance 254 is connected in series with slider 25I, causing this extreme position of slider 25I to have but a slight effect upon the motor position.

With slider 242' in the mid-position shown, only one-half of the resistance 245 is in circuit with this slider, and consequently movement of slider 242 will have a substantial effect upon the motor position. As previously mentioned,

. with the parts in'the position shown, the heat exchanger 98 is operating as an evaporator for absorbing heat from the water passing through Consenected in parallel with relay coil 2I5, while increasing the portion of this resistance which is connected in parallel with relay coil 2, this action thus tending to balance out the initial unbalancing action of the controller 20I It will be apparent thatwhen shaft 203 rotates an amount proportionate to the movement of slider 242 on resistance 243, the relay coils 2 and 2I5 will again become balanced for causing switch arm 216 to disengage contact 2" for stopping the motor at this point. Upon an increase in pressure within heat exchanger 98, the slider 242 will move ,to the left across resistance 243 and this will cause movement of the motor I99 in a direction for closing the valve I95 an amount proportionate to the pressure increase. It should therefore be apparent that the controller 20I will act, to cause opening of the valve I95 as the refrigerant pressure in heat exchanger 98 falls below 55 lbs. per sq. inch and will cause the valve I95 to be wide open when the refrigerant pressure falls to 50 lbs. per sq. inch. This action tends to maintain the refrigerant pressure substantially constant and thus supplies just enough heating water to the heat exchanger to meet the demands of the system.

When the system is operating on the cooling cycle, the heat exchanger 98 will operate as a condenser and therefore the refrigerant pressure therein at this time will be relatively high. This the left-hand end of resistance 243 will byitself' be incapable of maintaining the valve I in closed position. During the cooling cycle the controller 200 will control the valve I95 in a manner to maintain the refrigerant pressure within heat exchanger 98 between 116 and 120 lbs. per sq. inch. Thus if the refrigerant pressure rises to 120 lbs. per sq. inch, the slider 235 will engage the left-hand end of resistance 236 and at this time the resistance 240 will be entirely out of circuit with slider 235. Due to engagement of slider 235 with the left-hand end of resistance 236, the relay coil 2 will be substantially short-circuited while the entire resistances 236 will be connected in parallel with relay coil 2I5. Thi will cause switch arm 216 to engage ant pressure is at 120 lbs. per sq. inch, the valve I95 will be wide open. As the cooling load on the system decreases, less water will be required for condensing the refrigerant and consequently the refrigerant pressure will decrease; This decrease in pressure will cause slider 235 to move to the right across resistance 236 thus inserting a portion of this resistance in parallel with relay coil 2I4 and decreasing the portion of this resistance which is in parallel with relay coil 2I5. This will cause relay coil 2I5 to become more highly energized than coil 2I4 thus causing switch arm 2I6 to engage contact 2I8 for energizing motor field 208. Energization of motor field 208 will cause rotation of shaft 203 for closing valve I95 and, this rotation of shaft 203' will cause movement of slider 2II upwardly across resistance 2I2, thus tending to rebalance energization of relay coils 2I4 and 2I5. Therefore as the refrigerant pressure decreases, the valve I95 will be closed an amount proportionate to the de-.

crease in pressure and will tend to become completely closed when the refrigerant pressure falls to 116 lbs. per sq. inch. This action will proportion thewater supply to heat exchanger 98 during the summer cycle in accordance with the demand for cooling water.

In the event that either the controller 200 or 2III fails to supply enough water to heat exchanger 98 for preventing overheating of the engine 56, the slider I of the engine thermostat 292 will move from the extreme position shown towards the left across resistance 253. This will remove a portion of the resistance 254 from circuit with slider 25! thereby increasing the effect of slider 25I on the motor I99. Also the movement of slider 25I to the left across resistance 268 will decrease the portion of this resistance which is in parallel with relay coil 2I4 and increase the portion of this resistance which is in parallel with relay coil 2I5 thus causing switch arm 2I6 to engage contact 2!! for thereby opening the valve I 95. In response to this opening movement of the valve I95, the balancing potentiometer III] will rebalance the relay coils 2I4 and 2I5 when the valve I95 has been opened an amount proportionate to the movement of slider 25I on resistance 253.

The controllers 200, 2M, and 202 therefore conjointly control the valve motor I99 in a manner to increase the supply of water to heat exchanger 98 as the pressure increases when the system is operating on the summer cycle; to increase the supply of water when the refrigerant pressure decreases below a predetermined value when the system is operating on the cooling cycle; and to increase the supply of water at any time in the event that the engine becomes overheated. Due to the action of the auxiliary rheostats associated with each of these controllers, these controllers automatically reduce their effect upon the valve motor as they become satisfied, thereby transferring the control of the valve motor to any controller which is not satisfied.

It should be noted that switch arm I52a is connected into the engine starting and ignition circuit, and is actuated by the crank 209 in a manner to stop the engine whenever valve I95 is wide open. As valv I95 is opened wide when the compressor head pressure becomes excessive on the cooling cycle, when the suction pressure becomes excessive on the heating cycle, or when the engine overheats, this arrangement'provides a safety control for stopping the engine if any one of these conditions occurs. This will prevent damage to the engine from overheating, prevent freezing of water in heat exchanger 98 during I the heating cycle, and will stop the engine upon .energization of this failure of cooling water during the cooling cycle.

Referring to the resistance 262 which i interposed between the upper end of the balancing resistance 2I2 and the relay coil 2I4, the purpose of this resistance is to balance out the effect upon the relay coilsof the auxiliary rheostats. This resistance 262 should be one-half the value of the balancing resistance 2I2.

Operation of Figure 1 With the parts in the positions shown, the space temperature is approximately 71 F. as indicated by the slider gaging the center of its resistance I66. Due to the space temperature being below 72 F. the mercury switch I68 is closed and relay II! is energized. In the manner previously described,

relay has placed the potentiometer of thermostat I58 in control of the throttle valve motor I5'I, way valves 63 and 64 for causing operation of the system on the heatmg-cycle, has caused energization of the pump H4. and has placed the engine 56 into operation. Due to the system operating on the heating cycle, the heat exchanger 98 is operated asan evaporator and consequently the refrigerant pressure therein is relatively low as indicated by the slider 242 of controller 20I engaging the center of its resistance. This has caused the valve I to behalf open. Due to the slider I65 of winter thermostat I58 engaging the center of resistance I66, the throttle valve motor I51 has assumed a position in which the throttle valve I42 is half open. The engine 56 is therefore operating at an intermediate speed.

If the heating load upon the system increases, the space temperature will fall which will cause movement of slider I65 to the left across resistance I66 thereby causing the motor I51 to open the throttle valve I42 wider. This willincrease in the refrigerant pressure within the heat exchanger 98 becoming lower and in response to this fall in refrigerant pressure, the winter pressure controller 20I will operate'to open valve I95 wider for supplying a larger amount of water to the heat exchanger thus tending to maintain a substantially constant pressure within heat exchanger 98 and balancing -the water supply against the heating load. This arrangement provides for supplying just the proper amount of water to meet the requirements of this system, thereby conserving on operating expenses of the system.

As the heating load on the system decreases, the space temperature will increase and in response to this increase in space temperature, the winter thermostat throttle valve I42 towards closed position for I65 ofthermostat I58 enhas positioned three- I58 will cause shifting of the reducing the engine speed. This action will' sure controller 20I will reduce the supply of water to heat exchanger 90.

When the space'temperature rises above 72 F. the mercury switch I68 of thermostat I58 will deenergize relay H1 and this will transfer the control of the throttle valve motor I51 from the thermostat I58 to the thermostat I59. Deenergization of relay II1 additionally will position three-wayvalves 63 and 64 for operating the system on the cooling cycle. Additionally this deenergization of relay II1 will stop the pump II and will place the engine starting circuit under the control of the space relative humidity controller I81. At this time the engine will be stopped and started in accordance with the relative humidity in the space and its speed when in operation will be determined by the thermostat I59.

As pointed out previously, when the relative humidity within the space rises to a predetermined value, the engine will be started by the controller I81. If the space temperature is relatively low, such as 75 F., the thermostat I59 will cause the throttle valve I42 to be wide open thus causing operation of the engine at full speed. This will result in reducing the temperature of the heat exchanger to a minimum value whereby this heat exchanger will perform a relatively large amount of dehumidification as compared to sensible heat cooling. This will result in reducing the relative humidity in a very short time to a value at which the controller I81 stops the engine. Due to this short period of operation, only a small amount of cooling will be performed. As the space temperature increases, the engine will be operated at slower and slower speeds during its periods of operation as determined by the humidity controller I81. Thus when the space temperature is at 82 F. the engine will be operated at low speed which will cause the temperature of the heat exchanger to be relatively high at which time only a slight amount of dehumidification is performed as compared to the sensible heat cooling performed. This will require the engine 56 to operate for a substantial period of time before the relative humidity controller stops the engine, and consequently a large amount of cooling will be performed for maintaining the space temperature at a proper value. i

It should be noted that this control system will provide for intermittent reheat in the event that reheat is necessary in order to obtain proper humidity conditions within a space. For instance during cool damp weather the humidity within the space may be excessive while the temperature is fairly low. At this time the humidity controller will cause operation of the engine for dehumidifying the space. If this engine operation results in the space temperature falling below 72 F., the thermostat I58 will reverse the operation of the system thus causing the heat exchanger to now heat the space instead of cooling it. This heating action will continue until .the space temperature rises above 72 F. at

which time the system will again be placed on the cooling cycle thus permitting the dehumidiaction to continue.

' 98 in a manner to maintain substantially a con- During the cooling cycle the pressure controller supply of cooling water to the heat exchanger stant refrigerant pressure within this heat exchanger. Also during both the heating and the cooling cycles the engine temperature responsive thermostat 202 will operate to increase the supply of cooling water to the heat exchanger 98 and the engine in the event that the engine should commence overheating. In addition, whenever valve I95 becomes wide open, switch arm I52a will stop the engine for preventing damage to the system due to failure of water supply, or to other improper operating conditions.

Figure 4 Referring to Figure 4 this figure shows a slightly modified system from that shown in Figure 1. In this figure the details of the various controllers and relays have not been illustrated and the portions of this figure which are identical to the system of Figure 1 are indicated by the same reference characters.

In Figure 4 the refrigeration system is substantionally the same as for Fig. 1. However, the auxiliary evaporator mm of Figure 4 differs from the auxiliary evaporator of Figure 1 in that it is provided with a second heat exchange coil 300, the inlet of which is connected by a pipe 30I to the outlet of the engine water jacket, a thermostat 302 being provided for maintaining the engine temperature at a proper value. The outlet of heat exchange coil 300 is connected by a pipe 303 to a radiator 304 and this radiator is connected by pipe 305 to a pump 306 which in turn is connected by pipe 301 to the inlet of the engine water jacket. The pump 306 may be driven by the engine 56, and this pump causes the engine cooling water to circulate through heat exchange coil 300, radiator 300 and back to the engine. Due to the spray of liquid refrigerant over the heat exchange coil 300, the engine cooling water will give up its heat to this sprayed refrigerant, thereby providing for cooling of the engine and transfer of the jacket heat of the engine to the air being heated.

It should be noted that the auxiliary evaporator I00a of Figure 4 is connected into the refrigeration system in a slightly different manner from that shown in Figure 1. In Figure 4 the auxiliary evaporator I00a is also utilized as a receiver for the refrigerant thereby eliminating use of the separate receiver I08 of Figurel. In Figure 4 when the system is operating on the heating cycle, refrigerant will pass from the compressor 55 through pipes and 62 into threeway valve 54 and from three-way valve 60 through pipe 99 into the header II of heat exchanger 6, and the condensed refrigerant will pass from the heat exchanger 6 through the pipe IIG (as in Figure 1) to the pump I I4 which sprays it into the auxiliary evaporator I 0.011. The evapo rated portion of the refrigerant will pass from auxiliary evaporator I00a through pipe 308 to the pipe 60, and this refrigerant will pass back into the heat exchanger 6 along with the refrigerant being delivered by the compressor 55. Also liquid refrigerant at the bottom of auxiliary evaporator I00a will be drawn through pipe I I6 by the pump, Ill and ,resprayed over the heating surface as occurs in Figure l. The unevaporated portion of the liquid refrigerant leaves the receiver formed in' the bottom of auxiliary evaporator I00a, and passes through pipe vI09a through the expansion valve 1 l and. thence into the heat exchanger 98. This refrigerant is evaporated in exchanger 98 and passes through pipe 91 to the three-way valve 63 and from there through pipes 66 and 61 to the compressor.

When the system is operating on the cooling cycle, refrigerant will pass from the compressor through pipes 60 and BI to the three-way valve 63 and then through pipe 9'! into the heat exchanger 98 wherein it is condensed. This condensed refrigerant then passes through pipe II I, check valve H2, and pipe H6 into the receiver formed in the bottom of auxiliary evaporator 19a, and from there passes through pipe l09a to the expansion valve device l2 of the heat exchanger 6. The refrigerant then flows from this heat exchanger through pipe 99, three-way valve 64, and pipes 65 and 61 to the compressor. When the system is operating on the cooling cycle the pump H4 is out of operation and consequently no liquid refrigerant is sprayed over the coils IOI and 399 in the auxiliary evaporator. The

either on the cooling or heating cycle. Also it chamber within this auxiliary evaporator will remain in communication with the discharge line 60 of the compressor and the refrigerant pressure will therefore become equal to the compressor head pressure. This refrigerant is already in the gaseous state and consequently will merely fill the auxiliary evaporator'lfloa without absorbing heat from the heat exchange coils Jill and 300.

Reference character 3H3 indicates a motor driven fan for blowing air, across the radiator 304. This fan may be controlled by means of a thermostat 3H responsive to the engine temperature. The thermostat 3 may be of usual form and is shown as including a bellows 3l2 connected to a control bulb 3|3 in the engine water jacket, the bellows 3l2 actuating a mercury switch 3. This mercury switch 3 is connected in series with the fan 310 as shown. The thermostat 3 may be designed in a manner to place the fan 3m in operation whenever the engine temperature exceeds a predetermined value such as 170 F. During the heating cycle of this system the auxiliary evaporator IOlla should cool the engine cooling water sufficiently to maintain the engine temperature below 170 F. and consequently the fan 3l0 will remain out of operation. However, when the system is operating on the cooling cycle, the auxiliary evaporator llllla is out of operation and this will cause the engine temperature to rise to a value at which the fan 3"! is placed into operation. At this time the fan 3H1 will be placed into and out of operation by the thermostat 3 in a manner to maintain a substantially constant engine temperature.

It should be noted that in Figure 4, the heat exchanger 98 and the engine water jacket are not connected in series as in Figure 1. For this reason the water supply valve I95 for the heat exchanger 98 is controlled only by the two refrigerant pressure controllers 290 and 20!.

It should now be apparent that this invention provides a completely automatic summer-winter air conditioning system which utilizes .a refrigeration system operating on a normal cycle for cooling the space and which operates on a reversed cycle for heating the space. It should further be apparent that this invention utilizes an internal combustion engine for driving the compressor, provides for utilizing the waste heat from this engine when the system is operating on the heating cycle, and provides for properly cooling the engine when the system is operating should be seen that this invention provides a reversible cycle refrigeration system for use in air conditioning installations which utilizes a multiple pass type of heat exchanger in the air stream, and which provides for proper distribution of the liquid refrigerant to the various passes while the system is operating on the cooling cycle and which provides for eliminating the pressure drop of the distributing device when the system is operating on the heating cycle. It will further be seen that my invention provides for maintaining proper space conditions during both summer and winter and automatically changes from heating -to cooling operation depending upon space conditions.

While throughout this description I have mentioned specific values of temperature and pressure at which the various instruments may be set, it will be understood that these values are illustrative only and may be varied as desired for difierent installations and applications of my invention. While I have shown and described preferred forms of my invention, I do not limit myself to the specific embodiments shown, as many modifications and adaptations of various features andsubcombinations of my invention will occur to those skilled in the art. I therefore desire to be limited only by the scope of the appended claims.

I claim as my invention:

1. A conditioning system comprising, in combination, a refrigeration system including actu ating means and heat exchange devices in heat exchange relationship with a space to be conditioned and with a medium outside of said space to be conditioned, means'including valve means for connecting said devices to each other and to said actuating means in difierent manners to selectively cool or heat said space, pressure actuated means including a chamber having a movable wall for shifting at least a portion of said valve means from one position to another upon change in pressure applied to said movable wall, and means including pilot valve means for utilizing pressure differences within said system for changing the pressure applied to said movable wall sufiiciently to cause shifting of said valve means.

2. A conditioning system comprising, in combination, a refrigeration system including actuating means and heat exchange devices in heat exchange relationship with a space .to be conditioned and with a medium outside of said space to be conditioned; means including valve means for connecting said devices to each other and to said actuating means in a manner to selectively cool or heat said space, pressure actuated means for shifting said valve means from one position to another, means including pilot valve means for utilizing pressure differences within said systems for actuating said pressure actuated means, and yieldable means associated with said valve means and actuating means therefor for permitting movement of said valve means independently of said actuating means when the pressures within a portion of said refrigeration'system become undesirable.

bination, actuating means, a first device in heat exchange relationship with a space for cooling or heating said space, a second device in heat exchange relationship with a medium exterior of said space, means including valve means for 3. A conditioning system comprising, in comconnecting said devices to each other and to said actuating means in a manner to selectively cause said first device.to operate as an evaporator while causing said second device to act as a condenser,

or for causing said first device to act as a condenser while said second device acts as an evaporator, pressure actuated means including a chamber'having a movable wall for shifting at least a portion of said valve means from one position to another upon change in pressure applied to said movable wall, and means including pilot valve means for utilizing pressure differences within said system for changing the pressure applied to said movable wall sufiiciently to cause shifting of said valve means.

4. A conditioning system comprising, in combination, a compressor, a first heat exchange device' in heat exchange relationship with said space, a second heat exchange device in heat exchange relation with medium external of said space, means including a three-way valve for selectively connecting said first and second devices to said compressor in a manner for causing said first device to operate as a condenser while said second device acts as an evaporator, or for causing said first device to act as an evaporator while said second device acts as a condenser, said threeway valve having a first port connected to the outlet of said compressor, a second port connected to the inlet of said compressor, and a valve member for selectively placing either of said ports in communication with a third port, actuating means for said valve member, and yieldable means for permitting movementof said valve member to a position placing said first and second ports in communication when the pressure at the outlet of the compressor becomes excessive.

5. In a conditioning system, in combination, a refrigeration system including actuating means, a first heat exchange device in heat exchange relationship with a space to be conditioned, a second heat exchange device in heat exchange relationship with a medium external to said space, said first heat exchange device being formed to provide a plurality of parallel passes for the flow of refrigerant therethrough, a first expansion valve for said first heat exchange device, a second expansion valve for said second heat exchange device, a distributor connected to the outlet of said first expansion valve, said distributor including a chamber receiving the jet of liquid refrigerant from said first expansionvalve, and a plurality of restricted connections leading from said chamber to each of said first heat exchange device passes, means including valve means for connecting said heat exchange devices to each other and to said actuating means in a manner to selectively cause said first heat exchange defor causing said first heat exchange device to act as a condenser.

6. In a conditioning system, in combination, a

refrigeration system including actuating means and heat exchange devices, one of said devices ineluding a plurality of parallel passes, a distributor for distributing liquid refrigerant to said passes, said distributor including a plurality of restricted passages interposed between a source of liquid refrigerant supply and said passes, means including valve means for selectively causing said one heat exchange device to operate as an evaporator or as a condenser, a plurality of by-pass passages for by-passing said restricted connections, and check valve means interposed in said by-pass passages.

7. In a conditioning system, in combination, a refrigeration system including actuating means and heat exchange devices, one of said heat ex: change devices including a plurality of passes, means including valve means for causing said one heat exchange device to operate either as an evaporator or as a condenser, a distributor device for distributing liquid refrigerant to said one heat exchange device when it operates as an evaporator and for collecting liquid refrigerant from said one heat exchange device when it acts as a condenser, said distributor device comprising an inlet for liquid refrigerant, a plurality of restricted passages connecting said inlet to said passes, an outlet for liquid refrigerant, a plurality of passagesconnecting said passes to said outlet, and check valve means associated with said last mentioned passages.

8. In a conditioning system, in combination, a refrigeration system including actuating means, a first heat exchange device in heat exchange relationship with a space to be conditioned and comprising a plurality of parallel passes for refrigerant fiow, a second heat exchange device, expansion valve means for said first and second heat exchange devices, means including change-over valve means for selective-- ly causing said first heat exchange device to operate as an evaporator while said second heat exchange device operates as a condenser, or for causing said first heat exchange device to operate a a condenser while said second heat exchange device operates as an evaporator, a distributor device connected to said first heat exchange device for distributing liquid refrigerant to said passes when said first device is operating as an evaporator and for collecting liquid refrigerant from said passes when said device acts as a condenser, said distributor device including a plu rality of restricted passages, by-pass passages around said restricted passages, check valve means associated with said by-pass passages for causing refrigerant to be forced through said restricted passages when said first heat exchange device operates as an evaporator, while allowing flow of refrigerant through said by-pass passages when said first heat exchange device acts as a condenser, pressure actuated means for actuating said change-over v"lve means, means including pilot valve means f utilizing pressure differences within the refrigeration system for actuat ing said pressure actuated means, means for supplying medium to said second heat exchange device to heat said second heat exchange device when acting as an evaporator and for cooling said second heat exchange device when acting as a condenser, and means responsive to the pressure of the-refrigerant in said second heat exheat exchange devices, one of said heat exchange devices being arranged to operate either as an evaporator or as a condenser, means for supplying medium to said one heat exchange device for supplying heat to said one heat exchange device while it is operating as an evaporator and to cool said one heat exchange device while it is operating as a condenser, means responsive to conditions which are measures of the demand for cooling or heating medium for controlling said supplying means, and means actuated by said controlling means for stopping said compressor upon a predetermined demand for said medium.

10. In a conditioning system, in combination, a refrigeration system including a compressor and heat exchange devices, one of said heat exchange devices being arranged to operate either as an evaporator or as a condenser, an internal.

combustion engine for driving said compressor, means for supplying medium to said one heat exchange device and to said internal combustion engine in series, said medium acting to supply heat for said one heat exchange device while it is operating as an evaporator, to cool said one heat exchange device while it is operating as a condenser, and to cool said internal combustion engine, and means responsive to the refrigerant pressure within said one heat exchange device and to the temperature of said internal combustion engine for controlling said supplying means in a manner to increase the supply of medium upon rise or fall in said pressure above or below predetermined values, and upon rise in temperature of said engine above a predetermined value.

11. In a summer-winter air conditioning system, in combination, a refrigeration system including a compressor, and heat exchange devices, change-over valve means for causing one of said heat exchange devices to operate as an evaporator or as a condenser, an internal combustion engine for driving said compressor, means for supplying medium to said one heat exchange device and to said internal combustion engine in series, said medium acting to supply heat for said one heat exchange device while it is operating as an evaporator, to cool said one heat'exchange device while it is operating as a condenser, and to cool said internal combustion engine, means responsive to the temperature of said space for starting said internal combustion engine and positioning said change-over valve means in a manner to operate said one heat exchange device as an evaporator when space temperature falls below a predetermined value while positioning said change-over valve means in a manner to operate said one heat exchange device as a condenser when the space temperature is above such value, means for starting said engine when the space relative humidity rises to a value requiring dehumidification, means responsive to space temperature for varying the output of said engine when in operation while said' one heat exchange device is operating as a condenser, and means responsive to the demand for cooling or heating medium for said ,one heat exchange device and to the demand for cooling of said engine for controlling said medium supplying means.

12. In a summer-winter air conditioning system, in combination, a refrigeration system including a compressor, and heat exchange devices, change-over valve means for causing one of said heat exchange devices to operate as an evaporator or as a condenser, an internal combustion engine for driving said compressor, means restarting said internal combustion engine and positioning said change-over valve means in a manner to operate said one heat exchange device as an evaporator when space'temperature falls below a' predetermined value while positioning said change-over valve means in a manner to operate said one heat exchange device as a condenser when the space temperature is above such value, means for starting said engine when the space relative humidity rises to a value requiring dehumidification, and means responsive to space temperature for varying the output'of said engine when in operation while.said one heat exchange device is operating as a condenser.

13. In a summer-winter air conditioning system, in combination, a refrigeration system including actuating means and heat exchange devices, change-over valve means for causing one of said heat exchange devices to operate as an evaporator or as a condenser, means responsive to space temperature for starting said actuating meansand positioning'said change-over valve means in a manner to operate said one heat exchange device as an evaporator when space temperature falls below a predetermined value, while positioning said change-over valve means to operate said one heat exchange device as a condenser when space temperature rises above said value, means for placing said actuating means in operation when space relative humidity rises to a value requiring dehumidification, and means re- I sponsive to space temperature for varying the output of said actuating means at this time.

14. In an air conditioning system, in combination, a cooling and dehumidifying means for cooling and dehumidifying the air passed to a space being conditioned, humidity influenced means for placing said cooling and dehumidifying means into operation when the humidity within the space rises to a predetermined value, and temperature responsive means for increasing the capacity of said cooling and dehumidifying means upon decrease in space temperature, and for decreasing the capacity of said cooling and dehumidifying means upon increase in space temperature.

15. In a conditioning system, in combination, a reversible cycle refrigeration system including a compressor and a heat exchanger in heat exchange relationship with a space to be conditioned, change-over valve means for selectively causing said refrigeration system to cool or heat said space, an auxiliary evaporator associated with said change-over valve means and said heat exchanger in a manner to receive condensed refrigerant from said heat exchanger when'said change-over valve means is positioned for operating said heat exchanger as a condenser, means for causing refrigerant evaporated in said auxiliary evaporator to be returned to said heat exchanger, an internal combustion engine for driving said compressor, means for supplying waste heat from said engine to said auxiliary evaporator, and space condition responsive means for controlling said engine and said change-over valve means.

16. In a conditioning system, in combination, a reversible cycle refrigeration system including a compressor and heat exchangers in heat exchange relationship with a space to be conditioned and with medium outside of said space, change-over valve means for changing the flow of refrigerant through said refrigeration system in a manner to cause said system to cool said space when said change-over valve means is in one position, and to heat said space when said change-over valve means is in another position,

an auxiliary evaporator associated with one of gine for driving said compressor, means for supplying waste heat from said engine to said auxiliary evaporator, and means including said change-over valve means for placing said auxiliary evaporator out of operation when the system is operating for cooling the space.

1'1. In a conditioning system, in combination, a reversible cycle refrigeration system including a compressor and heat exchangers in heat exchange relationship with a space to be conditioned and with medium outside of said space, change-over valve means for changing the fiow of refrigerant through said refrigeration system in a manner to cause said system to cool said space whensaid change-over valve means is in one position, and to heat said space when said change-over valve means is in another position, an auxiliary evaporator associated with one of said heat exchangers for receiving liquid refrigerant therefrom and for returning evaporated refrigerant thereto, an internal combustion engine for driving said compressor, means for supplying waste heat from said engine to said auxiliary evaporator, a pump associated with said last mentioned heat exchanger and said auxiliary evaporator for aiding circulation of refrigerant therebetween, and means for placing said pump out of operation when said system is operating to cool the space.

18. In a conditioning system, in combination, a reversible cycle refrigeration system including a compressor and heat exchangers in heat exchange relationship with a space to be conditioned and with medium outside of said space, change-over valve means for changing the fiow of refrigerant through said refrigeration system in a manner to cause said system to cool said space when said change-over valve means is in one position, and to heat said space when said change-over valve means is in another position an auxiliary evaporator associated with one said heat exchangers for receiving liquid refrigerant therefrom and for returning evaporated refrigerant thereto, an internal combustion engine for driving said compressor, means for supplying waste heat from said engine to said auxiliary evaporator, a pump associated with said lastmentioned heat exchanger and said auxiliary evaporator for aiding circulation of refrigerant therebetween, and temperature responsive means for controlling said internal combustion engine and said pump in a manner to place said engine and pump in operation when the temperature to which said temperature responsive means responds falls to a predetermined value.

19. In a heating system, in combination, a condenser in heat exchange relationship with a zone to be heated, an evaporator for absorbing heat from outside of said zone, a compressor connected to said condenser and evaporator, an internal combustion engine for driving said compressor, an auxiliary evaporator receiving heat from said internal combustion engine, means including a pump for passing liquid refrigerant from said condenser to said auxiliary evaporator to be heated, an evaporator for absorbing heat from outsideof said aone,a compressor connected to said condenser and evaporator, an auxiliary evaporator receiving heat from an outside source, said auxiliary evaporator including heat exchange surface, and means for passing condensed refrigerant from said condenser over said heat exchange surface, for returning evaporated refrigerant from said auxiliaryevaporator to said condenser, and for collecting unevaporated,

refrigerant which has passed over said heat exchange surface and recirculating it over said surface.

21. In a heating system, in combination, a'condenser in heat exchange relationship with a zone to .be heated, an evaporator for absorbing heat from outside of said zone, a compressor connected to said condenser and evaporator, an internal combustion engine for driving said compressor, an auxiliary evaporator, means for passing liquid refrigerant from said condenser to said auxiliary evaporator and for passingevaporated refrigerant from said auxiliary evaporator to said .condenser, a heat exchange device in said auxiliary evaporator, means for passing cooling water from said engine through said heat exchange device, supplemental cooling means for said cooling water, and means for placing said supplemental cooling means into'and out of operation.

22. A conditioning system comprising, in combination, a compressor, a first heat exchange device in heat exchange relationship with said space, a second heat exchange device in heat exchange relation with medium external of said space, means including a three-way valve for selectively connecting said'first and second devices to said compressor in a manner for causing said first device to operate as a condenser while said second device acts as an evaporator, or for causing said first device to act as an evaporator while said second device acts as a condenser, said three-way valve having a first port connected to the outlet of said compressor, a second port connected to the inlet of said compressor, and a valve member for selectively placing either of said ports in communication with a third port, pressure actuated means including a chamber having a movand temperature responsive means for placing said pump into and out of operation.

denser in heat exchange relationship with a zone able wall for shifting said valve member from one position to another upon change in pressure applied to said movable wall, means including pilot valve means for utilizing pressure differences within the refrigeration system for changing the pressure applied to said movable wall for thereby changing the position of said valve member, and yieldable means for permitting movement of said valve member to a position placing said first and second ports in communication when the pressure at the outlet of the compressor becomes excessive.

23. In a reversible refrigeration system, in combination, a compressor, heat exchange devices, one being in heat exchange relationship with a space and another being in heat exchange relationship with a medium external to said space, valve means for selectively causing said system to heat or cool said space, said valve means communicating with the inlet and outlet of said compressor and normally placing said inlet and outlet out of direct communication, and means for positioning at least a portion of said valve means in a manner to place said inlet and outlet in direct communication when the pressure at the outlet of the compressor becomes excessive for thereby relieving such excessive pressure.

24. In a reversible refrigeration system, in

combination, a first heat exchanger, a second heat exchanger, a compressor having an inlet and an outlet, selective valve means communicating with the inlet and outlet of the compressor for selectively connecting the outlet of the compressor to the first heat exchanger and the inlet to the second heat exchanger or connecting the inlet to the first heat exchanger and the outlet to the second heat exchanger, piping means including expansion valve means between said heat exchangers, means for supplying medium for cooling said first heat exchanger when it acts as a condenser and for supplying heat thereto when it acts as an'evaporator, a valve for controlling the flow of said medium, a motor for positioning said valve, and control means responsive to the pressure of the refrigerant in said first heat exchanger for controlling said motor in a manner to open said valve upon rise in pressure above a predetermined high value or upon fall in pressure below a predetermined low value.

25. A refrigeration system including actuating means and heat exchange devices, one of said heat exchange devices being arranged to operate either as an evaporator or as a condenser, means for supplying medium to said one heat exchange device for providing a source of heat when said one heat exchange device is acting as an evaporator and for cooling said one heat exchange device when it acts as a condenser, a valve for controlling the flow of said medium at all times, a motor for positioning said valve, and control means responsive to conditions which are measures of the demand for heating or cooling of the refrigerant in said one heat exchanger for controlling said motor in a manner to open said valve upon demand for heating or cooling.

26. In a reversible refrigeration system, in combination, compressing means andheat exchange devices, said compressing means comprising a.

compressor mechanism and a driving mechanism therefor, reversing means for causing one of said heat exchange devices to operate either as an evaporator or as a condenser, means for passing medium into heat exchange relationship with one of said mechanisms and through said one heat exchange device for thereby cooling said one mechanism and either cooling or heating said heat exchange device, a valve for controlling the flow of said medium, a motor for positioning said valve, means responsive to the temperature of said one mechanism for controlling said motor in a .manner to open said valve upon rise in temperature of said one mechanism, and means responsive to conditions which are a measure of the de- I mand for heating or cooling of said one heat exchange device for controlling said motor in a manner to open said valve independently of said temperature responsive means upon demand for either heating or cooling of said one heat ex change device.

27. In a reversible refrigeration system, in combination, compressing means and heat exchange devices, said compressing means comprising a compressor mechanism and a driving mechanism therefor, reversing means for causing one of said heat exchange devices to operate either as an evaporator or as a condenser, means for passing medium into heat exchange relationship with one of said mechanisms and through said one heat exchange device for thereby cooling said one mechanism and either cooling or heating said heat exchange device, valve means for controlling the flow of said medium through said one heat exchange device and into heat exchange relationship with said one mechanism, means responsive to the temperature of said one mechanism for controlling said valve means in a manner to increase the flow of said medium upon increase in said temperature, means responsive to demand for cooling of said one heat exchange device for controlling said valve means in a manner to increase the flow of medium independently of said temperature responsive means upon increase in demand for cooling of said one heat exchange device, and means responsive to the demand for heating of said one'heat exchange device for controlling said valve means in a manner to increase the flow of medium independently of said temperature responsive means upon increase in demand for heating of said one heat exchange device.

28. In a reversible refrigeration system, in combination, compressing means and heat exchange devices, said compressing means comprising a compressor mechanism and a driving mechanism therefor, reversing means for changing the system from heating to cooling and vice versa, means for supplying medium to at least one of said heat exchange devices when the system is cooling and for furnishing heat to at least one of said heat exchange devices when the system is heating, means for also passing said medium in heat exchange relationship with one of said mechanisms for cooling the same, a valve for controlling the flow of said medium, a motor for positioning said valve, thermostatic means responsive to the temperature of said one mechanismfor controlling said motor in a manner to open said valve upon rise in temperature of said one mechanism, and means responsive to' the demand for said medium by said heat exchange devices for opening said valve independently of said thermostatic means.

29. In an air conditioning system, in combination, a direct expansion cooling coil for cooling and dehumidifying the airin a space, a variable capacity compressing means connected to said cooling coil, a first controller for placing said compressing means into and out of operation, a second controller for varying the capacity of said compressing means, a device responding to the relative humidity of the air in said space for controlling said first controller to start the compressor when relative humidity rises to a predetermined value, and a thermostat responding to space temperature for controlling said second controller in a manner to reduce the capacity of the compressing means upon rise in temperature.

30. In a system of the class described, in combination, a heat exchange device, a compressing means connected to said heat exchange device,

said compressing means including a compressing mechanism and a driving mechanism therefor,

controlling means for varying the supply of heat

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