US2244312A

US2244312A - Refrigeration system

Info

Publication number: US2244312A
Application number: US199216A
Authority: US
Inventors: Alwin B Newton
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1938-03-31
Filing date: 1938-03-31
Publication date: 1941-06-03
Anticipated expiration: 1958-06-03

Description

June 3, 1941.

A. B. NEWTON 2,244,312 REFRIGERATION SYSTEM Filed March 31, 1938 2 Sheets-Sheet l 3noentor Lon dttorneg Allwiin 113. NH

fi f

June 3, 1941. T N 2,244,312

REFRIGERATION SYS TEM Filed March 51, 1938 2 Sheets-Sheet 2 ZSnventor Alwilm B. Newton attorney of the condensers being positioned of the type above described Patented June 3, 1941 UNITED STATES PATENT OFFICE Alwin B. Newton,

I Minneapolis-Honeywell Minneapolis, Minn., a corporation of Delaware Application March 31, 1938, Serial No. 199,216 19 Claims- (CL 62-4 This invention relates to a tem and more particularly system of the mechanical type.

One of the objects of this invention is the provision .of a novel arrangement for more efliciently operating a refrigeration system.

, More specifically it is an tion to provide a refrigeration system of the mechanical type wherein the condenser is positioned in a location subject to wide temperature varia ions and wherein means are provided for circulating refrigerant from the condenser to the evaporator without the use of the compressor during such times as the temperature of the air surrounding the condenser is lower than the temperature to be maintained in the space being cooled by the evaporator.

Another object of this invention is the provision of a refrigeration system having a pair of condensers connected together in parallel, one in a location subject to widetemperature variations, whereby the condenser which frigerant being compressed.

A further object is the provision of a system using two condensers arranged in parallel with a pump separate from the compressor for circulating refrigerant through the system with the compressor out of operation when the temperature of the air surrounding the condenserwhich is positioned in the location subject to wide temperature variations becomes lower than the it is desired to maintain in the air ing the evaporator.

other objects will become apparent upon a study of the specification, claims, and appended drawings wherein like reference characters represent like parts in the various views and wherein: k

Figurel is a schematic view of one form of refrigeration system embodying my invention;

Figure 2 is a view similar to Figure 1 but illussurround- I trating a different control means forthe'refrig crating apparatus; 8

and v Figure 3 isa modification Figure l'wherein two condensers are provided, these condensers being arranged in parallel.

Referring more specifically to Figure 1, a compressor is represented by the reference characobject of this inven-' is surrounded by the cooler, -air will be more effective in condensing the retemperature which refrigerating systo a refrigerating of the system of ter Hi, this compressor being driven by any suit- I ablemeans as by a motor II, this motor being controlled in a manner to be hereinafter described. Connected to th high pressure side ture Regulator Company,

of the compressor "I is a pipe l2 leading to a condenser IS, the outlet of the condenser being connected to a receiver it. A pipelS is connected to the outlet of the receiver I4 and leads to the inlet of a pump l6, this pump being connected to a driving motor H. The outlet of the pump I8 is connected by means of a pipe l9 to an expansion valve 20 which controls the flow of refrigerant into the evaporator coil 2|. The evaporated refrigerant flows from the evaporator coil 2| through a pipe 22 back to the inlet of the compressor ill. The evaporator coil 2| is shown as being mounted in a suitable fixture 2i and located within the fixture is a thermostat 25. This thermostat is shown to comprise a bellows 26 which is filled with a suitable volatile fluid, this bellows controlling the position of a lever 21 which is pivoted at 28 and biased by means of a spring 29 into engagement with the top of the bellows. Carried by the lever 21 is a mercury switch 39, this switch including contacts 3i and 32 and a mercury element 83. when the temperature within the fixture 24 is at a high enough value, the bellows 26 is expanded as illustrated and switch 30 is accordingly tilted to the position wherein the contacts 3i and 32 are electrically connected by the mercury element 32. Upon a drop in temperature in the box, the bellows 26 contracts and after the temperature drops to a predetermined value the switch a will be tilted circuit through the contacts 3| and 32 is interl2 through which the flows is a bellows 35.

rupted.

Connected to the pipe high'pressure refrigerant pivoted at 31 and biased by means of a spring 38 into engagement :with the upper portion of the bellows, the lever 86 carrying a mercury switch 29; When the pressure of the refrigerant leaving the compressor is below an excessively high value the switch 89 will be tilted to the position illustrated wherein contacts ment therein. However, when the pressure becomes excessive the mercury switch will be tilted in the opposite direction whereupon the circuit through the contacts 40 and II will be interrupted. v

The condenser I! will preferably be positioned in a location which is subject to wide temperature variations such as outside the building for example. Positioned adjacent the condenser is a thermostat 45 which is subject to the temperaof the air surrounding the condenser i3.

to a position wherein the I ill and II are electrically connected to the mercury ele- I the compressor The thermostat 45 may include a bellows 46 provided with a suitable volatile fill, this bellows controlling the position of a lever 41 pivoted at 48 and biased by means of a spring 49 into engagement with the upper portion of the bellows 46. Carried by the lever 41 is a mercury switch 52, this

switch including contacts

53, 54, 55, and 56. When the temperature adjacent the condenser I3 is above a predetermined value, the bellows 46 is expanded and the switch 52 is tilted in the directionshown so that

contacts

55 and 56 are connected bymeans of the mercury element in the switch 52. However, when the temperature adjacent the condenser falls to apredetermined low value, the contraction of the bellows 46 will cause the mercury switch 52 to .be tilted in the .other direction wherein the

contacts

53 and 54 are connected together by the mercury element. i

For supplying power to the motors I I and I1 line wires 60 and 6| are provided, these line wires being connected to a suitable source of power (not shown). When the temperature within the fixture 24 is above a predetermined value and switch 30 is in the position shown and when the temperature adjacent the condenser I 3 is highenough so that switch 52 is tilted to the position shown, the motor II which drives the compressor I will be energized by means of the following circuit: ,.from line 60 through conductors 62, mercury switch 30, conductor 63,

terminals

55 and 56 of mercury switch 52, conductor 64, the mercury switch 39, it being assumed that the pressure on the discharge side of the compressor is not excessive at this time, conductor 65 through motor II and conductor 66 to the line wire 6|. No current flows through the motor I! at this time so that the cooling of the fixture by the evaporator 2| is effected by the compressor I II in the conventional manner. The pump I6 is shown as being a centrifugal pump so that the flow of refrigerant therethrough is not impededby reason of the fact that this pump isnot operating at this time. In the event however, that a pump of the positive displacement type were used in place of the centrifugal pump I6, a valve controlled by-pass could be provided around the pump to permit the flow of refrigerant through the system when the pump is not in operation. The compressor In will continue to operate as long as the

switches

30, 39, and 52 remain tilted in the directions illustrated. Should the temperature of the fixture get sufliciently low so that switch is tilted in the opposite direction the motor III will shut down. Likewise should the discharge pressure of the refrigerant leaving the compressor become excessively high. the switch 39 will be tilted by the bellows in a position to interrupt operation of the compressor motor.

Should now the temperature of the air surrounding the condenser' I3 become sufllciently ,low, or in other words, lower than the temperature which it is desired to maintain in the fixture 25, the bellows 46 will contract sufllciently to tilt switch 52 in a position wherein the

contacts

53 and 54 are connected together by the mercury element. in this direction interrupts the circuit through motor, thus placing the compressor out of operation.. If the temperature of the fixture is still above the desired value a circuit will be established through the motor IT as follows: from the line wire 60 through con- This tilting of the switch 52' ductor 62, the mercury switch 30, conductor 63,

contacts

54 and 53 of mercury switch 52, conductor 68 through the motor I1, and conductor 66 to the line wire 6|. The motor I1 is now placed in operation and causes pump I6 to pump refrigerant from the condenser I3 through the evaporator'coil 2| and back to the condenser I3. A suitable by-pass I0 controlled by a check valve 'II is provided for permitting the refrigerant to by-pass the compressor III when the compressor is not operating. This valve will permit flow of refrigerant through the valve II in the direction of the arrow but will not permit flow in the reverse direction so that when the compressor I0 is inoperation the pressure on the left side of the valve will be considerably higher than on the oppositeside so that no refrigerant flows through the by-pass I0. However, when the compressor I0 is shut down and pump I6 is in operation the pressure on the left side of the valve will be lower than on the right side so that refrigerant will by-pass the compressor III. This bypass and check valve fII might be omitted if the valves of the compressor are not excessively stiif so that refrigerant can flow through the compressor in response to operation of the pump I6. A fan I2 is driven by the motor I1 and causes a circulation of air over the condenser I3 when the motor I! is operating to facilitate the cooling thereof.

It should now be apparent that when the pump I6 is operating due to the reason that the temperature of the fixture is above the desired value and that the temperature of the air surrounding the condenser is below the value which it is desired to maintain in the fixture 24, then the system is operating as a simple heat transfer system, the heat of the fixture being transferred to the cold air surrounding the condenser, I3. This provides for great economy or operation since the pump I6 can be operated with a considerably less expenditure of energythan the compressor I0 while at the same time effecting the necessary cooling of the fixture 24 when the temperature of the air surrounding the condenser is at a low enough value. It will therefore be seen that with this system, thetemperature of the fixture is cooled very economically when the temperature of the air surrounding the condenser is sufliciently low.

Referring now to Figure 2 the refrigeration system except for the control means is illus-L trated as being identical with that of Figure 1. Instead of the thermostat 25 responsive to the temperature of the air within the fixture 24, a device responsive to the suction pressure of the compressor is provided, this device giving an indication of the temperature of the evaporator. This device maycomprise a bellows 15 connected by means of a pipe I6 to the pipe 22 connecting the evaporator to the inlet of the compressor ID. The bellows 15 controls the position oi a mercury switch 18 mounted on alever I6 pivoted at 86, this lever being biased by means of a spring 8| into engagement with the upper por-:

tion of the bellows 15. When the pressure on the low side of the system falls to a predetermined value the bellows 15 will contract and move the mercury switch to a position wherein the circuit through the contacts 83 and I4 interrupted by the mercury element.

When the suction pressure is high enough so that the switch I8 is tilted in the position illu s-- trated the evaporator coil temperature will be above the desired value, it being understood that the suction pressure is an indication of evaporator temperature and the compressor motor II will be placed in operation, assuming that the temperature of the air surrounding the condenser I3 is not too low and that the pressure on the discharge side of the compressor is not too high, by means of the following circuit: from the line conductor 89, the mercury switch 39, conductor 90,

contacts

55 and 55 of the mercury switch 52, conductor 9|, compressor motor II, and conductor 92 to the line 6|. The compressor will continue to operate until either the suction pressure in the system drops to a predetermined low value indicating that the coil temperature has dropped to a low enough value, until the pressure on the high pressure side of the system exceeds a certain yalue, or until the temperature of the air surrounding the condenser l3 drops to a sufficiently low value. Assume now that the temperature of the air surrounding the condenser is at such a low value that switch 52 is tilted to the position wherein the contacts '53 and 54' are connected together by the mercury element, I

that the switches 39 and 18 are in the positions illustrated, the motor II will be energized through the following circuit: from the line wire 60 through conductor 85, switch 18, conductor 89, switch 39, conductor 90,

contacts

54 and 53 of the mercury switch 52, conductor 94, the motor I! and conductor 95 to the line wire 6|. The compressor 10 at this time is not operating since the circuit through the contacts 55 and 58 of the switch 52 has been interrupted and thepump 16 will circulate refrigerant through the system in the same manner as in Figure 1. .It will now be apparent that the systems of Figure 1 and Figure 2 operate in a, similar manner except that in Figure 1 the operation of the compressor l and the pump I6 is controlled by the temperature of the fixture 24 whereas in Figure 2 they are controlled in accordance with the suction pressure of the system or in other words, according to the temperature of the evaporator coil.

Referring now to Figure 3, a refrigeration system similar to that of Figure 1 is illustrated except that the means for condensing the refrigerant comprises a pair of condensers I00 and HH arranged in parallel, both of these condensers having their inlets connected to the discharge side of the compressor l0 and their outlets connected to the receiver l4. The compressor I00 may be located outside the building as illustratedwhere it is subjected to variations in outdoor temperature whereas the condenser llH may be located inside the building adjacent the compressor II! which in turn may be remotely located from the cooling chamber 24 as for example, in the basement of a building. The temperature of the air surrounding the condenser ID! will fluctuate relatively little throughout the year Whereas the temperature of the air surrounding the evaporator I00 may fluctuate between relatively high and low values depending upon the season of the year. During those portions of the year where the outdoor temperature is relatively condenser I!!!) will have relatively little or no condensing effect on the refrigerant and most of the condensing will take place within the condenser I0l-. These condensers should each. have sufficient capacity so that either one of the condensers may do all the condensing of the refrigerant that is necessary for satisfactory operation of the system.

During cool weather the outdoor temperature will drop below the temperature of the air surhigh, the

-60 through conductor 86, mercury switch 18,

rounding the condenser l0l so that a considerable portion of the condensing of the refrigerant may take place in the condenser {00. When the temperature outdoors falls below the temperature which it is desired to maintain in the fixture 24, the thermostat 45 which responds to outdoor temperature will transfer the control of the system from the compressor Ill to the pump IS in the same manner as has been set forth in connection with Figure 1, and the system will then operate as an ordinary heat transfer system for transferring the heat from the fixture 24 to the outdoor air by means of the condenser 100 without the necessity of operating the compressor l0.

Accordingly with this system, variations in relative indoor and outdoor temperatures are most effectively utilized for efficiently operating the .refrigerating system so that when the outdoor temperature is lower than the indoor temperature the condensing will take place in the condenser exposed to the outdoor air and conversely when the outdoor temperature becomes. relatively high most or all of the condensing of the refrigerant will take place in the condenser- II. It will be unlikely in a system of the type shown in this figure that the air surrounding the condenser llll will ever become lower than the temperature which it is desired to maintain in the fixture 24 so that the pump l5 responds only to the outdoor temperature. However, if for some reason or other the temperature surrounding the condenser I0! should at certain times be lower than the temperature of the air surrounding the condenser I00 and should also be lower than the temperature it is desired to maintain'in the fixture 24, the pump l6 may be operated both in response to the indoor and outdoor temperature so that when either of these temperatures is lower than the temperature that it is desired to maintain in the fixture 24 the pump will be operated and the compressor placed out of operation. The controller 25 responsive to the temperature of the fixture 24 may if desired be replaced by a. suction pressure controller 'as in Figure 2.

Having described the preferred forms of my invention, many modifications may become apparent to those skilled in the art. For example, any other suitable system for controlling the operation of the compressor may be substituted 4 for those illustrated. If desired, pump l6 might be operated whenever the compressor operates as well as' at other times, thus assisting in the circulation of the refrigerant. In such case, when the compressor and pump are in operation simultaneously, or if the fan 12 be run continuously, the condenser associated therewith may be operated as an evaporative condenser. The systems illustrated may be used with multiple coil installations as well as with single coil installations as illustrated. It should therefore be under stood that my invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, means for causing a circulation of refrigerant from the condenser to the evaporator and back to the condenser, and means responsive to the temperature of the air surrounding said condenser for interrupting operation of the compressor when the temperature drops to a low predetermined value and causing operation of said refrigerant circulating means. a 2. A refrigerating system including a compressor, a condenser and an evaporator, said com- 3. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, means independent of the operation of the compressor for causing circulation of refrigerant from the condenser to the evaporator and back to the condenser, controlling means for the compressor and said circulation causing means, said controlling means including means responsive to the temperature of the air surrounding said condenser for causing operation of the compressor when said temperature is above a predetermined value and for interrupting operation of the compressor and causing operation of the circulation causing means when said temperature is below a predetermined value.

4. A refrigeration system including a compressor, a condenser, and an evaporator, said condenser being positioned in a location subject to temperature variations, means independent of the operation of the compressor for circulating refrigerant from the condenser to the evaporator and back to the condenser, means responsive to a condition which is a measure of the demand for cooling for controlling the operation of the compressor or the circulating means, and means responsive to the temperature of the air surrounding =said condenser for placing the compressor or the circulating means under the control of said last named means.

5. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, a pump separate from the compressor for circulating refrigerant from the condenser to the evaporator and back to the condenser, means responsive to a condition which is a measure of the demand for cooling by the evaporator for selectively controlling the operation of the compressor or the pump, and means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of said condition responsive means when the temperature is above a predetermined value and for placing the pump under the control of said condition responsive means when the temperature is below a predetermined value.

6. A refrigeration system including a compressor, a condenser and an' evaporator, said condenser being positioned in a location subject to temperature variations, a pump separate from the compressor for circulating refrigerant from the condenser to the evaporator and back to the condenser, means responsive to a condition which is a measure of the demand for cooling by the evaporator for selectively controlling the operation of the compressor or the pump, means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of said condition responsive means when the temperature is above a predetermined value and for placing the pump under the control of said condition responsive means when the temperature is below a predetermined value, and means operated conjointly with said pump for causing a circulation of air past said condenser.

7. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, a pump for causing a circulation of refrigerant from the condenser to the evaporator and back to the condenser when the compressor is not operating, means responsive' to the temperature of the air being cooled by the evaporator selectively in control of the compressor and the pump, and means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of the first named temperature responsive means when the temperature of the air surrounding the condenser is above a predetermined value and for placing the pump under the control of the first named temperature responsive means when the temperature of the air surrounding the condenser is below a predetermined value.

8. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, 2. pump for causing a circulation of refrigerant from the condenser to the evaporator and back to the condenser when the compressor is not operating, means responsive to the temperature of the air being cooled by the evaporator selectively in control of the compressor and the pump, means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of the first named temperature responsive means when the temperature of the air surrounding the condenser is above a predetermined value and for placing the pump under the control of the first named temperature responsive means when the temperature of the air surrounding the condenser is below a predetermined value, and means operated conjointly with the pump for causing a circulation of air over said condenser.

9. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, a pump for causing a circulation of refrigerant from the condenser to the evaporator and back to the condenser when the compressor is not operating, means responsive to the pressure on the suction side of the refrigeration system for selectively controlling the operation of the compressor and the pump, and means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of the pressure responsive means when the temperature of thejair surrounding the condenser is above a predetermined value and for placing the pump under the control of the pressure responsive means when the temperature of the air surrounding the condenser is below a predetermined value.

10. A refrigeration system including a compressor, a condenser and an evaporator, said condenser being positioned in a location subject to temperature variations, a pump for causing a circulation of refrigerant from the condenser to pressor, an evaporator, and a pair pressor, an evaporator, and a pair of parallelly densers to the evaporator the evaporator and back to the condenser when the compressor is not operating, means responsive to the pressure on the suction side of the refrig-' eration system for selectivelycontrolling the operation of the compressor and the pump, means responsive to the temperature of the air surrounding the condenser for placing the compressor under the control of the pressure responsive means when the temperature of the air surrounding the condenser is above a predetermined value and .for placing the pump under the control of the pressure responsive means when the temperature of the air surrounding the condenser is below a. predetermined value, and means operated conjointly with said pump for causing a circulation of air over said condenser.

11. A refrigeration system including a comof parallelly arranged condensers, one of said condensers being located adjacent said compressor and the other of said condensers being positioned in a location subject to wide temperature variations, means independent of the operation of the compressor for circulating refrigerant from the condensers to the evaporator and back to the con- 25 densers, means responsive to a condition which is a measure of the demand for cooling by the evaporator for controlling the operation of the compressor or the circulating means, and means responsive to the temperature of the air surrounding said last named condenser for selectively placing the compressor or the circulating means under the control of said last named means.

12. Av refrigeration system including a comarranged condensers, one of said condensers being located adjacent said compressor and the other of said condensers being positioned in a location subject to wide temperature variations, means independent of the operation of the compressor for circulating refrigerant from the conand bacls to the condensers, means responsive to a condition which is a measure of the demand for cooling by the evaporator for controlling the operation of the compressor or the circulating means, means responsive to the temperature of the air surrounding said last named condenser for selectively placing the compressor or the circulating means under the control of said last named means, and means operated conjointly with said circulating means for causing a circulation of air over said last named condenser.

13. A refrigeration system includin a compressor, an evaporator, and a pair of parallelly arranged condensers, one of said condensers being located adjacent saidvcompressor and the other of said condensers being positioned in a location subject to wide temperature variations, a pump for causing a circulation of refrigerant from the condensers to the evaporator and back to the condensers, means responsive to the temperature of the air being cooled by the evaporator for controlling the operation of the compressor and the pump, and means responsive to the temperature of the air surrounding said last named condenser for placing the compressor under the control of the first named temperature responmined value and for placing the pump control of the first named temperature responsive means when the temperature of the air surtor for controlling evaporator and circulating rounding said condenser is below a predetermined value. 1 v

14. A refrigeration system including a compressor, an evaporator, and a pair of parallelly arranged condensers, one of said condensers being located adjacent said compressor and the other ofvsaid condensers being positioned in a location subject to wide temperature-variations,

a pump for causing a circulation of refrigerant from the condensers to the evaporator and back to the condensers, means responsive to the temperature of the air being cooled by the evaporathe operation of the compressor and the pump, means responsive to the temperature of the air surrounding said last-named condenser for placing the compressor under the first named temperature responthe temperature of the air surrounding said condenser is above apredetermined value and for placing the pump under the con- 'trol of the first named temperature responsive means when the isbelow a predetermined value, and means operated conjointly with the pump for causing a circulation of air over said last named condenser. c h

15. In a refrigerationsystem, an evaporator, a condenser positioned in a location subject to variations in temperature, a first means for causing a circulation of refrigerant through the condenser and evaporator and causing operation of the evaporator to effect cooling even though the temperature at the location of the condenser is not relatively low, a second meansfor causing a circulation of refrigerant through the condenser and evaporator and causing operation of the evaporatorto effect cooling only when the temperature at the location of the condenser is relatively low, and means responsive to location of the condenser for'controlling the operation of the first circulating means.

16. In a refrigeration system, an evaporator, a condenser positioned in a location subject to vari-' circulation of refrigerant through the condenser and evaporator and causingoperation of the evaporator to effect cooling even thoughthe temperature at the location of the condenser is not relatively low, a second means for causing a circulation of refrigerant through the condenser and evaporator and causing operation of the evaporator to effect ture at the location of the condenser is relatively low, and means for controlling operation of the first and; second circulating means, said means including means responsive to a condition which is a measure of the demand: for cooling by the means responsive to the temperature at the location of the condenser.

1'7. A refrigeration system pressor, an evaporator and condensing means, said condensing means being cooled by a medium subject to temperature variations and which at times falls below the necessary operating temperature of the evaporator, whereby at times oom- 'pression of the refrigerant is necessary for condensing while at other times the refrigerant may be condensed! without compression, and means 7 actuated when compression .of the refrigerant is not operating.

18. A refrigeration system in: means, condensing means,

including evaporatand circulating temperature of the air surrounding said condenser the temperatureat the cooling only when the temperaincluding a complacing means for circulating refrigerant from the conin a manner to prevent substantial compression oi the refrigerant thereby. .19. A refrigeration system including evaporating means, condensing means, means including a compressor for withdrawing evaporated refrigerevaporating means, compressin it, the compressed refrigerant into ant from the and d WIN B. NEWTON.