US2342566A - Air conditioning apparatus - Google Patents

Description

Feb. 22, 1944. E. R. WOLFERT AIR CONDITIONING A PPARATUS Filed Jan. 17, 1944 2 Sheets-Sheet l NOW WMQOQQOb QQNQ Il nl,

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l Innen for E DWARD RWOLFERT Feb. 22, 1944. E. RWOL'FERT 2,342,566

AIR CONDITIONING APPARATUS Filed Jan. 17, 1944 2 Sheets-Sheet 2 In /6 f2 M f l A, 6 y, L

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ATTOR Patented Feb'. 22, l1944 .un CONDITIONING APPARATUS Edward R.Wolfert. Springeld, Mass., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 17, 1944, Serial No. 518,513

9 Claims. (Cl. 6Z--129) This application is a continuation-impart ofl my application Serial No. 400,161, iiled June 28,

My invention relates to air conditioning apparatus, more particularly to a reversible cycle refrigerating system for either heating or cooling air for comfort, and it has for an object to provide improved apparatus of the character set forth.

. Another object is to provide a reversible cycle refrigerating system which is simple, inexpensive and reliable.

A more particular object is to provide a reversible cycle refrigerating system, for either heating or cooling an enclosure, `which may be manufactured at only a small additional cost above that of a refrigerating system adapted for cooling only.

A further object is to provide a reversible cycle -refrige'rating system for either heating or cooling an enclosure, and which system has provision for transferring heat from the condensed refrigerant to the expended refrigerant in the suction conduit during both the heating and the cooling cycle.

'I'he reversible cycle refrigerating system of my invention comprises the usual compressor, two heat exchangers to serve as the condenser and the evaporator, and an expansion device connected between the two heat exchangers. The expansion device comprises a passage of considerable length and restricted ilow area and which is constantly open and provides constant restriction to ilow. Such device is preferably a tube which is commonly referred to in the art as a capillary tube. Means including a reversing valve is provided for connecting the compressor discharge to one heat exchanger to serve as the condenser and connecting the compressor suction or inlet to the other heat exchanger which serves as the evaporator during the heating cycle, and for reversing the connections to the two heat exchangers for the cooling cycle. The connecting means just mentioned includes a suction conduit which is connected between the compressor suction or inlet and the reversing valve and which contains suction gas during both cycles 'of operation. This conduit is arranged in heat transfer relation to the expansion device to provide transfer of heat `from the expanding gas to the suction gas during both cycles of operation.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in accordance with the vaccompanying drawings, forming a part of this application, in which:

Fig. 1 -is a diagrammatic view oi a reversible cycle refrigerating system in accordance with my invention;

Fig. 2 is a sectional view of the reversing valve;

Fig. 3 is a detail sectional view showing the shaped end of the capillary tube;

Fig. 4 is a perspective view of a windowmounted unit containing a reversible cycle refrigerating system in accordance with my invention; and

Fig. 5 is a diagrammatic view of a reversible cycle refrigerating system incorporating a modied'form of heat exchanger;

Referring to the drawings in detail, I show a reversible cycle refrigerating system including two heat exchangers Ili and II which may be of the conventional cross-finned serpentine coil type. Provision is made for conveying air over the coil I0 and delivering the same to the-en closure to be air conditioned. The coil Il serves as the evaporator during-the cooling cycle and as the condenser during the heating cycle. Provision is also made for conveying outside air over the coil I I and for discharging the same to outdoors or other place exterior oi the enclosure. The coil II serves as the condenser during the cooling cycle and as the evaporator during the heating cycle. The runs or tubes of each coil are preferably connected to provide a refrigerant path extending from the top through the-successively lower adjacent runs to the bottom of the coil, so that. when the coil is serving as the condenser, the condensed refrigerant flows by gravity to the bottom o! the coil.

The refrigerating system also includes al motorcompressor unit I2 which is preferably enclosed within a fluidtight.casing I3, as shown, and as is now well known in the art. It further includes a reversing valve Il which is adapted to place the compressor suction and discharge in communication with the coils III and II, respectively, or with the coils II and Ill, respectively. Conduits I5 and I6 connect the reversing valve with the upper ends of the coils I0 and II, respectively. A suction line, including a conduit I1, a reservoir or accumulator I8 and a conduit I9, connects the reversing valve to the compressor s'uction or inlet, and a discharge conduit 2l connects the reversing valve to the compressor discharge. The accumulator I8 is adapted to retain larger particles and bodies of liquid. while the vanorized refrigerant, together with some liner particles of liquid entrained therein. readily passes from the top of the accumulator into the conduit I9.

While any suitable construction of reversing valve may be used so far as the present invention is concerned, I prefer to use the one which is shown in Fig. 2 and which will be readily apparent from the drawings. It includes an axiallymovable valve member 22 having annular ribs or ridges 23 and 24 which extend into annular recesses 25 and 23 communicating with the conduits I1 and 2|, respectively. The reversing valve is provided with a knob 21 which is screwthreaded into the movable member 22 and which is adapted to move the same axially. When the movable valve member 22 is moved to the left so that the ribs 23 and 24 seat against the left-hand sides of the recesses 25 and 26, as shown in Fig. 2, the conduit I6 is placed in communication with the conduit 2| and the conduit I is placed in communication with the conduit I1. When the movable valve member 22 is moved to the right to seat the ribs 23 and 24 against the righthand sides of the recesses, the conduit I3 is placed in communication with the conduit I1, and the conduit I5 is placed in communication with the conduit 2I through the passage and the ports formed in the valve member 22, as shown in Fig. 2.

In accordance with the present invention, I provide an expansion device which comprises a passage of considerable length and restricted flow area, and which is constantly open and provides constant restriction tov now. I prefer a tube having such characteristics and which is commonly referred to in the art as a capillary tube. The capillary tube serves as the expansion device during both the heating and the cooling cycle, the direction of flow being different for the two cycles. The tube is shown at 21 and is connected at its opposite ends to the lower ends of the coils III and I I.

' The capillary tube 21 is of suitable length and bore to provide the desired impedance or restriction to flow. For example, I have used and found satisfactory a tube twenty-eight inches long -and having a bore of .055 inch, in a window-mounted unit oi' the type shown in Fig. 4 having a capacity of 6000 B. t. u. per hour when operating as an air-cooled room cooler and circulating 1.67 cubic feet per minute of Freon 12 or dichlorodifluoromethane at 39 pounds per square inch and 72 degrees F.

'A strainer 23 is connected between the coil I0 and the tube 21 to strain the refrigerant when flowing from the former to the latter, and a strainer 29 is connected between the coil II and the tube 21 for straining the refrigerant when flowing to the tube in the opposite direction. Each' end of the tube 21 is shaped to provide asuitable inlet. ThisI shaping is preferably in accordance with Patent No. 2,134,542 of C. F. Alsing, and is shown in Fig. 3. 'I'he end or edge of the wall forming the tube is preferably of somewhat reduced thickness, which is preferably provided by tapering or inclining the outer surface of the tube wall, as indicated at 23a. The end or edge is rounded, as indicated at 29a, the curving or lrounding extending from the inner surface or bore of the tube to the inclined or tapered outer surface. The end of the capillary tube 21 extends into a connecting conduit portion 3l whose internal diameter is somewhat greater than the external diameter of the tube 21. By rounding the edge, the accumulation of lint or other foreign particles at the inlet is practically eliminated, since any such particles, by reason of the rounding, slide of! the rounded edge and are either drawn into the bore of the tube and carried through, or slide of! the outside into the larger space-provided by the connecting conduit portion 3|.

The capillary tube 21 is arranged in heat transfer relation to the conduit I3, which is a1- ways a part of the suction line, preferably by soldering the two together for a suitable length, thereby providing a heat exchanger 30.

The system shown and described may be mountedin any suitable air conditioning unit or installation. It is well suited to be incorporated in a portable self-contained unit, `such as the unit 32 shown in Fig. 4, mounted in a window 33a, as is well known in the art. The unit ls shown from the interior of the room which it serves, the room air inlet being shown at 33 and the outlet being shown at 34. The knob 21a for actuating the reversing valve I4 is seen at the right-hand end of the unit. The apparatus is arranged within the unit 32 in any suitable manner, the coil IIJ contacting the room air owing from the inlet 33 to the outlet 34 and the coil II contacting outside air which enters and leaves through the outdoor side of the unit. For example, the arrangement disclosed and claimed in the patent of J. L. Ditzler and R. E. Holmes,

No. 2,329,342, issued September 14, 1943, may

be used.

Operation When the refrigerating system is tobe used for cooling the enclosure, the reversing valve I4 is positioned as shownin Fig. 2, in which position the compressor discharge conduit 2| is placed in communication with the conduit I6 leading to the outside air coil II and the suction conduit I1 is placed in communication with the conduit I5 leading to the conditioned air coil I0. The refrigerant compressed by the motor-compressor unit I2 now flows as indicated in Fig. 1 by the solid line arrows, first through the conduit 2|, through the connecting passage in the reversing valve I4 and the conduit I6 to the outdoor air coil II. In the latter, the high-pressure, hightemperature refrigerant gives up heat to a stream of outdoor or outside air circulated over the coil and is thereby condensed. The condensed refrigerant then flows through the strainer 29 and enters the capillary tube at the left-hand end. As it ows through the tube 21, its pressure is gradually reduced. Therefrigerant discharged from the capillary tube 21 flows through the strainer 23 in reverse direction and enters the conditioned air coil I0 at the lower end. It then flows through the successive turns until it reaches the upper end. As it flows through the coil l0, it cools the air flowing over the coil, and is vaporized by the heat extracted therefrom. The vaporized refrigerant is discharged from the top of the coil and passes through the conduit I5, the connecting passage of the reversing valve I4 and the suction line (including the conduits I1 and I9 and the accumulator I8) to the inlet or suction conduit of the motor-compressor unit I2.

In the heat exchanger 30,' the vaporized refrigerant flowing through the suction conduit I9 extracts heat from the expanding refrigerant nowing in the capillary tube 21, whose temperature is substantially above the temperature of the vaporized refrigerant since its pressure has not yet been fully reduced. The heat extracted from the refrigerant in the capillary tube increases by like v,heat transfer.

amolmttothecapacityoftherefrigeranttoabsorb heat in the coil Il. During the cooling cycle, the streams of refrigerant ilow in opposite or counterilow relation through the heat exchanger 2li thereby providing more eiiicient and effective To heat the enclosurel the reversing valve Il is moved to the right, thereby'placingnthe discharge conduit 2i vin communication with the conduit Il and placing the suction conduit I1 in communication with the conduit I8. The direction of now of refrigerant through the compressor and the suction and discharge conduits remainsthesameasduringthecoollngcycle,but the direction of now through the coils and the capillary tube is reversed and is indicated by the dotted-line arrows.

The compressed refrigerant flows through the discharge conduit 2|. the connecting 'e of the reversing valve Il and the conduit Ii into the conditioned air coil Il. As it flows through the coil Il, it gives up superheat and latent heat to the air circulating over the coil and is condensed. The heated air is. delivered to the enclosure to maintain the latter at' a comfortably warm temperature. The condensed refrigerant flows through thesuccessive tubes to the bottom of the 21 iextends from the-left-hand end, first along anunattached portion, then along the conduit 29a in upstream direction, along the conduit Itb in downstream direction, and then along an unattached portion to the right-hand end. The remainder f the refrigerating system shown in Fig. 5 is similar to that shown in Figs. l Vto 4.

Fig. 's-'operation .L The operation of the embodiment shown in Fig. 5 is the same as that of the rst embodiment exceptas to the heatv transfer taking yplace in the heat exchanger 30a. Duringthe cooling coil I l from which itfiows through thestrainer/ 28 and enters the right-hand end oi' capillary tube 21. It l5 discharged from the latter atthe Y left-hand end, flows through the strainer 29 in reverse direction, and enters the lower end of the outside -air coil II. .As it ilows through the latter, it absorbs heatfrom the outside air flowing over the coil- I l and is thereby vaporized. The vaporlzed refrigerant is discharged from the upper end of the coil, ows through the conduit Il, the connecting passage of the reversing valve Il, the suction conduit I1, the accumulator Il, and the suction conduit Il lto the motor-compressor unit I2,vwherein it is recompressed.

As the vaporized refrigerant ilows through the portion of the suction conduit I! which is in heat transfer relation to the capillary tub -21 it extracts heat from the expanding refrigerant in the latter. During the heating cycle, the flow of refrigerant through the capillary tube 21 is reversed, while the vaporized refrigerant continues to flow in' the same direction through the suction conduit I. 'Ihe two streams flow in the saine direction, from right to left, as seen in Fig. 1. Accordingly, the amount of heat transferred from the expanding refrigerant in the capillary tube to the vaporized refrigerant in the suction conduit is not as great as during the cooling cycle, when the streams ilow in opposite directions. However, a substantial amount of heat is transferred to the vaporinedrefrigerant, by v which it is carried vas Superheat to the coil I. where it is transferred to the airbeing heated.

In Fig. 5, I show a reversible cycle refrigerating system in which the heat exchanger has been modified to provide the sameeheat transfer from the expanding refrigerant in the capillary tube to the vaporized refrigerant in the suction line for both the heating andthe cooling cycle.

'Ihe heat exchanger designated 30a, comprises 'two suction conduits, Ila and Ilb, which convey the vaporized refrigerant from the accumulator Il to the motor-compressor unit I2. The capillary tube 21 has a portion soldered to each of the conduits Ila and IIb in what may be termed a symmetrical t. The capillary tube cyclepthe expanding refrigerant inthe capillary tube flows in counterflow heat transfer relation to the vaporized refrigerant in the conduit I9a and then flows in heat transfer relation to the vaporized refrigerant in the suction conduit lsb in .concurrent flow relation. During the heating cycle, the condensed refrigerant enters the right-hand end ofthe capillary tube, flows in counterilow heat transfer relation to the vaporized refrigerant in thesuction conduit I9b and then in concurrent flow heat transfer relation to the vaporized refrigerant in the conduit Isa.

VThe character of the heat flow is the same for both \cycles, first countex'flow and then concurrent flow.y A f While I have,shown my invention in several formsit will b e obvious to those skilled in the art that it is 'notsolimited but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall 4be 'placed thereupon as are specicall'y set forth in the appended claims.

What I- claim is:

1. In a reversible cycle refrigerating system for heating or cooling air for an enclosure, the combinationv of a compressor first and 'second heat exchangers, the second heat exchanger being arranged to heat or cool a-ir for the enclosure, a capillary tube connected betweensaid heat exchangers and serving to expand refrigerant from condensing pressure to evaporatlng pressure during both the heating and the cooling cycle, va suction. conduit connected to the suction of said' compressor, and means including a reversing lvalve for selectively lconnecting said suction conduit and -the discharge o f said compresser to said first vand said second heat exchanger, respectively, during the heating cycle,

or to said second and said first heat exchanger,

respectively, during the --cooling cycle, said suction conduit and said capillary tube being varranged in heat transfer relation to transfer heat from the expanding refrigerant'in the capillary tube to the expended refrigerant in the suction conduit during both the .heating cycle and cooling cycle.

2. In a reversible cycle refrigerating systein for heating or cooling air for anenclosure, the combination of a compressor, first and second heat exchangers, the'second heat exchanger being arranged to heat or cool air for theenclosure, a suction conduit connectedto the suction of said compresson'means including reversing valve mechanism for selectively connecting said suction conduit and the discharge of said compressor to said first and second heat exchanger, respectively,A for heating air for the enclosure, or to said second and said rst heat exchanger, re-

spectively, for cooling air for the enclosure, and

and restricted bore and arranged'for at least a portion of its length in yheat transfer relation to said suction conduit for expanding refrigerant from condensing pressure to evaporating pressure during the heating cycle and providing a passage of considerable length and restricted bore and arranged for at least a portion o! its length in heat transfer relation to said suction conduit for expanding'the refrigerant from condensing pressure toevaporating pressure during the cooling cycle.

3. In a reversible cycle refrigerating system for'heating and cooling air for an enclosure, the combination of a compressor, tlrstand second heat exchangers, the second heatv exchanger be `ing arranged to heat or cool air for the enclosure, an expansion device having a constantly I open passage of considerable length and restricted flow area providing constant restric- `first heat exchanger, respectively, during the cooling cycle, lsaid-suction conduit and said passage being arranged in heat transfer relation for transferring heat from they expanding refrigerant in said passage to the expended refrigerant in said suction conduit during both the heating cycle and the cooling cycle.

4. In a reversible cycle refrigerating system for heating or cooling air for. an enclosure, the

combination of a compressor, first and second heat exchangers, the second heat exchanger .being arranged for heating or cooling air for an enclosure, an expansion'device having a constantly open passage of considerable length and restrictediiow area providing constant restriction to flow, said passage being connected between said heat'exchangers andserving to expand refrigerant from condensing pressure to evaporating pressure during both the heating and the cooling cycle, means including a reversing valve for connecting the suction or inlet and the discharge of the compressor tol said first and said second heat exchanger, respectively, during the heating. cycle and to said seeond and said first heat exchanger, respectively,

during the cooling cycle, anda i'eservoir or accumulator connected in the suction line between the reversing valve and the suction or inlet of the compressor for separating'and retaining liquid portions from the refrigerant received from @o that heat exchanger which. is serving as the evaporator.

5. In a reversible cycle refrigerating system for heating or cooling air for an enclosure, the

combination of a compressor, first and second g5 heat exchangers, the second heat exchanger being arranged for heating or cooling air for an enclosure, ,capillary tube means connected between said heat exchangers and providing a constant restriction to flow when operating on tor.

suction of the compressor for retaining therein` `variable quhntities of liquid refrigerant occasioned by variation in operating conditions.

6. In a reversible cycle refrigerating system for heating 'or cooling air for' an enclosure, the combination of a compressor, first and second heatexch'angera the second heat exchanger being arranged .for heating or cooling air for an enclosure, a capillary tube connected between said heat `exchangers and providing a constant restriction expansion device during both 'the y heating and the cooling cycle, means including areversing valve for connecting thev suction and thedischarge of the compressorto said first and said second heat exchanger, respectively, during the heating cycle andto said second and said ilrst heat exchanger, respectively, during the cooling cycle,l and a reservoir or accumulator connected in the suction line between the` reversing valve and the suction or inlet of the compressor for separating and retainingliquid portions from the refrigerant received from that heat exchanger which is serving as the evapora- 7. The combination set forth in claim 6 wherein said capillary tube is in heat transfer relation to a portion of the suction line between `the accumulator and the compressor inlet.

8. In a reversible cycle refrigerating system i for heating or cooling air for an enclosure, the combination of a compressor, first and second heat exchangers, the second heat exchanger being arranged to heat or cool air for the enclos-` sure, a capillary tube connected between' said a heat exchangers and serving to expand refrig- '1\erant fromV condensing pressure to evaporating ipressure during both the heating andthe cooland said first heat exchanger, respectively, for

the cooling cycle, said capillary tube being ar ranged in heat transfer relation to said branches of the suction conduit in such manner that the refrigerant flowing through the capillary 'tube flows in counterilow relation to the refrigerant in one branch and in concurrent flow relation to the refrigerant in the other branch.

9. 'I'he combination set forth in claim 8 wherein the refrigerant flowing through the capillary tube flows iirst in counterflow relation to the refrigerant in one branch of the suction'conduit and then in concurrent ilow relation to the refrigerant in the other branch.

EDWARD R. WOLFERT.

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