US2239019A - Absorption type refrigerating system - Google Patents

Description

April 22, 1941. E. H. RYDEN EI'AL 2,239,019

ABSORPTION TYPE REFRIGERATING SYSTEM Filed Aug. 12, 19:58 2 Sheets-Sheet 1 |NV1:'.NTOR ERIC H. RYDEN ALBERT c. SCHICKLER ATTORNEYS Patented Apr. 22, 1941 Eric H. Ryden, Bedford, and Albert C. Schickler.

Beechwood, Ohio, assignors to The Bryant Heater Company, Cleveland, Ohio, at corporatlon of Ohio Application August 12, 1938,8erial No. 224,458

- refrigerant, such as ammonia, from the absorb- 9 Claims.

This invention relates to intermittent absorption type refrigerating systems, its object being to provide improved means for producing at the proper times a. cooling eii'ect upon either or both of the boiler-absorber and receiver or condenser.

More particularly the invention has for its-ob- Ject to provide a secondary cooling system, independent of fluid connection with the primary refrigerating system, and so arranged as to be capable of receiving heat by transfer from the primary refrigerating system and to conduct the heat away for dissipation elsewhere.

A further object is to provide a secondary cooling system' of the kind described, charged with its own refrigerant separate and apart from.

the refrigerant in the primary system, and consisting of a closed circuit embodying a condenser at which the absorbed heat is dissipated, as well as an evaporator portion in heat transfer relation with a part of the primary refrigerating system, such as the boiler-absorber or the receiver or condenser, for the purpose of utilizing the effect of the secondary cooling system for the purpose of applying a cooling effect to the primary refrigerating system.

Further objects of the invention are in part obvious and in part will appear more in detail hereinafter.

In the drawings Fig. 1 represents, diagrammatically, one form of apparatus embodying the invention, the cooling effect being applied to the boiler-absorber alone; and Fig. 2 is a similar diagrammatic view of another system embodying the invention in which the cooling effect is applied both to the boiler-absorber and to the receiver or condenser.

While the invention may be applied for use with any form or arrangement of intermittent or cyclic absorption type refrigerating system. the drawings, forsimplicity of illustration and in no sense of limitation, illustrate an absorption type refrigerating system comprising the usual boiler-absorber i communicating by way of the pipe 2, liquid seal trap 3, rectifier t and Pipe 5 with the evaporator 6, which in turn communicates by pipe 7 with the condenser and receiver 8. The cooling'coils t of the evapora tor communicate by way of a pipe it with a liquid seal trap ii within the evaporator, saidtrap communicating by drain pipe 82 with the trap 3, the latter communicating by return pipe i3 with the boiler-absorber.

The primary refrigerating system described operates in the usual manner. Heat applied by ing liquid, such as water, and drives it by way of pipe 2 and trap 3 to the rectifier 4 from which entrained absorbing liquid returns to the boiler. The vapor continues by way of pipe 5 to the evaporator and by pipe 1 to the condenserrecelver where the liquefied refrigerant collects pending completion of the heating phase of the cycle.

Upon reversal, when burner i4 is turned oil and the supply of,heat ceases, the boiler-absorber cools down, resulting first in return of the liquefied refrigerant from the condenser-receiver by way of pipe 1 to the evaporator, followed by evaporation of the liquid in the evaporator and return of the vapor tothe boiler by way of pipe lit for absorption in the absorbing liquid.

, in the bottom of the evaporating coils 9 and the .pipe ila by which they communicate with the evaporator 8. When, at the beginning of the next refrigeratingv period, the condensate com.

ing from the condenser 8 is discharged into the evaporator 6 it forces the liquid in the coils 9 and pipe 90. up through pipe l0 into the trap vessel ii within the evaporator reservoir 6. This is merely a matter of displacement of liquid. Asthe level of liquid rises in evaporator 6 it also rises in the pipe ill, which finally overflows into. the vessel ii. At the end of this refrigerating'period the concentration of refrigerant in the liquid in vessel ii is very low. Said vessel communicates with the seal 3 by pipe i2, whose upper end is disposed inside of and near the bottom of vessel ii and whose lower end-is disposedbelow the liquid level in the seal 3. During the ensuing heating period the rising pressure in the refrigerating system compresses the vapor in conduit I 2 betw en its two sealed ends. The liquid therefore rises into the pipe I! both from the trap 3 and the receiver ll, finally spilling over from the receiver H past the bend at the top of the pipe i2, and starting a-siphoning effect at the upper end of the drain tube, causing the liquid to rise from vessel ii and flow by way of pipe "back to seal 3 and thence to the boiler-absorber.

The secondary cooling system forming the burner II to the boiler-absorber i distills the subject matter of the present invention may be effect alone upon the boiler-absorber. ring to the arrangement shown-in .Fig. 1, the

'secondarycooling system includes an evaporator a applied to one ormore of theparts of the primary refrigerating system which it is desired to cool, such as either the boiler-absorber or the condenser and receiver, or both thereof. In Fig.

1 the secondary cooling system is applied for its part suitably designed for transfer of heat to it from the boiler-absorber, such as a pipe i1 lying Referin the liquid space of the boiler-absorber below its normal liquid lever A-A. The evaporator 7 part may also include a pipe II in the vapor space in the boiler absorber above its normal liquid levelA-A and. if desired,.provided with heat transfer fins IO in-the vapor space for in-- creasing the heat transfer effect. Said two pipes Ii, ll, together forming the evaporator portion, communicate together or in parallel, with a riser pipe ll communicating with a liquid seal trap l9 beyond which a pipe extends upwardlyto the top of -'a condenser 2| which ins.

eludes coils or turns of pipe provided with heat radiating fins or'members 22 if desired. 'The condenser drains to a descending pipe 23 com-.

' municating with the liquid seal trap 24 which,

in turn, communicates with a descending pipe 25 having a downward bend 26 at the boilerabsorber communicating in parallel or with'each ofthe pipes ll, ii. The condenser 2| need not be directlyabove the boiler-absorber, as shown,

but spatially is independent thereof. Also, the

boiler-absorber I and the parts associated there- .-frigerating system. In other words. each is charged with its own refrigerant. The two refrigerants may be the same but, preferably, the refrigerant in the secondary cooling system should have a low vapor pressure at high temperatures. For example, when using ammonia When the burner II is turned off and the supply of heat ceases, liquid begins to flow down wardly tovthe bottom of the secondary cooling system producing a greater liquid column in pipe 23, trap 24 and pipe 25 than the liquid column in pipe 20. As the liquid from pipe 25 finally enters the evaporating portion l5, ll of the secondary cooling system, pressure is built up therein, blowing over the liquid'seal in the rising leg 20, toward the condenser. Circulation starts and continues, the liquid refrigerant evaporating in the evaporator tubes l5, II, the vapors rising through leg i8, i8, 20 to be liqueiied in condenser 2| and returned for reuse.-

The condenser 2| obviously is located at some place where its heat will be dissipated elsewhere than to the primary refrigerating system, such as to the atmosphere by a current of air flowing across the turns or coils of the condenser.

sulate the generator-absorber from the rest of the apparatus. The production of a. cooling effeet at the generator-absorber induces the return of the condensate to the evaporator of the primary system and the subsequent production of refrigeration therein.

The secondary system being inactive duringthe heating period, it-is possible to lower the concentration of the absorption liquid. No ab-- sorption loop communicating with the absorber .is required, so that it is unnecessary to store strong solution in this part of the system and the charge of refrigerant ordinarily required for i the absorption loop may be dispensed with.

in the primary refrigerating system, the refrigerant in the secondary cooling system may be methylene chloride (commonly known as carrene) or sulfur dioxide. Other refrigerants may i be used, however. a

In operation,"during the heating period, heat will be applied by burner H to the boiler-absorber and by the flame jets Ila thereof to the U -bendl28. In the primary refrigerating system the heating phase of the cycle goes on as usual. In the secondary cooling system, the effect of the heatapplied to the U-bend28 is to vaporize some of'the liquid in said'bend. The vapor produced in .the leg of the *U-bend com-1 municating with pipe '26 forces the liquid out of i this pipe through the trap 24 into. the lower part of condenser 2| and in the other leg of the U- bend forces the liquid out of the evaporator purging it of inertygas.

tubes i5, i1 upwardly through pipe II and trad is, establishing counterbalancing liquid columns,

one in pipe 23 and the lower partof condenser- 2| and the other in pipe 2| above the liquid seal trap it. when this condition is reached there will be no material circulation or flow in the secondary cooling but the liquid refrigerant remains trapped in condenser 2| at a Fig.2 illustrates another embodiment of the invention in which a cooling effect is produced by the secondary cooling system at both the boiler-absorber and the receiver or condenser.

Here, too, the primary refrigerating systenirectifier It to the evaporator 35 and to condenser-receiver 2!, from which the liquefied refrigerant is returned to the evaporator 35. During the refrigerating phase of the cycle the .vapors .return by way of pipe 22 to the trap 32 and thence by way of pipe 31 to the boiler-absorber beneath the level of liquid therein. 3| indicates the drain return pipe, operating as .before described.

Condenser receiver 36 is shown equipped at itsu'iglit-himd end with .a standard form of valve, communicating with a pipe extending along the upper portion of the space within said condenser receiver, said valve being usedboth for charging the system with refrigerant and for .The secondary cooling system, in this form of 1 the invention, includes a suitable evaporator portion at the boiler, shown as a double-walled hollow cylinder a forming a chamber it which pressure only slightly higher than that corre- I spending to the temperature ofair around the condenser 2|.

, communicates by h riser pipe 4| with a liquid seal trap ('2, communicating by an upward bend in the pipe I! with a liquid seal trap or'vessel, 4!. The rising leg also includes a pipe 45 lead! ing fromthe trap l2 to the top of the condenser 40 which drains to a reservoir 41 communicat:

'ing' by wayof a trap I} and pipe, with cham- I ber 46. Condenser-receiver 86 is jacketed, as at 60, to provide a second evaporator portion for the secondary cooling system, the chamber Si in the Jacket communicating by a rising pipe 52 with the top of the condenser 46, and also communicating by the pipe 53, with the reservoir 41.

The boiler-absorber 38 may be heat insulated from the rest of the apparatus, as by the insulating shield 64, and the vessel 44 may be disposed, as by the wall 65, in a separate flue duct from the main duct in the shield 54. Here, also, the burner 56 for heating the boiler-absorber may have one or more jets 66a located to heat vessel 44.

The operation of the primary refrigerating system shown in Fig. 2 is the same as that shown in Fig. 1, including both the heating and refrigerating phases of the cycle, as well as the. drain efiect. Description thereof, therefore, need not be repeated.

It will be assumed that in .the system shown in Fig. 2 the same refrigerants may be used for boththe primary and secondary systems, as in the form shown in Fig. 1. The secondary cooling system, in Fig. 2, is'charged with sufficient refrigerant to insure a liquid level in the reservoir 41 with the jacket chamber 6| and the several liquid seals completely filled, whilethe reservoir 41 should also have sumcient additional capacity to take up or receive all of the liquid refrigerant from chamber 8i when its liquid voltime is displaced during one part of the operating cycle of the machine.

So far as the operation of the secondary cooling system, is concerned, when burner 56 is lighted, heat is applied not only to the boiler absorber but also to the vessel 44, the liquid in which is forced by the pressure generated therein upwardly through pipe 43 into trap 42, to fill the same and establish a liquid seal in pipe 45 leading to the top of the condenser 46. The volume of vessel 41 is suiilciently large to insure a liquid seal height H at the trap 42 greater than the liquid seal height C that is formed at the same time at the trap 48, as the liquid in the chamber 40 is forced out of this vessel into reservoir 41 by the heat supplied tochamber 44 from the heated absorption solution in the generator-absorber 30. Thus, in a short time, chamber 40 contains only superheated vapor and practically no heat transfer takes place between the generator-absorber and the secondary cooling system. Any liquid that may come back through pipes 4i and '49 from the traps 42 and 48 respectively to chamber 46, is immediately re-evaporated and returned to said traps. The heating cycle, therefore, progresses without effact one way or the other at the boiler-absorber.

As the heating cycle continues, warm vapor of the primary refrigerant gradually finds its way to the condenser-receiver 36, causing evaporation of the secondary refrigerant in chamber The vapor produced in the secondary cooling system rises through pipe 52, is condensed in the condenser 46, flows by gravity to vessel 41 and returns by pipe 53 to chamber 5i to be reevaporated for accepting more heat from the condenser-receiving and carrying it away to the condenser 46 for dissipation there. During this phase of the cycle, therefore, a cooling effect is being produced at the condenser-receiver 86 by the conjoint operation of the evaporating chamber' 6i and condenser 46, but no cooling effectis being produced at the boiler-absorber.

when the burner 56 is shut off, the vessel 44 is cooled and the pressure therein lowers. The liquid in trap 42 and pipe 46 then returns to vessel 44, clearing the way in the rising leg 4|, 42,

chamber 40 by way of pipe 49 from the vessel 41,

as the result of the liquid head therein. Thus,

circulation of secondary refrigerant is estab- I lished from the evaporating chamber 48 by way communication with the system, one of said evaporator members being of rising leg 4i, 42, 45, to condenser 46, and by way of reservoir 41, trap 48 and pip 49 back again to the evaporating chamber 40, with the net effect of cooling the boiler-absorber by transfer of heat to the secondary cooling system for dissipation at the condenser 46. q

As the temperature of the generator-absorber, during this portion of the'cycle, is considerably higher than that of condenser 36 and its cooling jacket chamber 6i the chamber 5i becomes filled with secondary liquid refrigerant, which remains here, inactive, for the duration of the absorption or refrigerating period of the primary ref rigerating system.

This arrangement, therefore, without valves or other mechanically operating parts, alternately effects the cooling of both the condenser and the generator-absorber of an intermittently operating absorption type refrigerating system, using a single heat dissipating element, the condenser 46, to perform both functions.

With this arrangement it is possible to utilize a secondary cooling system charged with a refrigerant which permits the use of copper in the finned coil, and to use one finned coil for cooling both .the condenser and the generator-absorber, thus materially increasing efllciency of the apparatus. Also, the use in the secondary cooling system of a refrigerant having a lower vapor pressure than the refrigerant in the primary refrigerating system, makes it possible to reduce the maximum pressure in the secondary cooling system, as will be readily understood. Other advantages will be apparent to those skilled in the art.

What we claim is:

' 1. The combination with a primary refrigerating system of the intermittent absorption type including generator-absorber and condenser elements in circulatory communication with each other, of a secondary cooling system including a condenser member and two evaporator members both in closed circulatory communication with said condenser member and independent of communication with the primary refrigerating system, one of said evaporator members being in heat transfer relation with the said generatorabsorber element and the other with the said condenser element, and means whereby the generator-absorber-cooling evaporator member is efiective during only the refrigerating phase of the cycle.

2. The combination with a primary refrigerating system of the intermittent absorption type including generator-absorber and condenser elements in circulatory communication with each other, of a secondary cooling system including a condenser member and two evaporator membersboth in closed circulatory communication with said condenser member and independent 01' primary refrigerating in heat transfer relation with the said generatorabsorber element and the other with the said condenser element, and

means whereby the con- 4. The combination with a denser-cooling evaporator member is effective during only the heating phase of the circle.

' in heat transfer 3. The combination with a primary refrigerating system of the intermittentabsorption type including generator-absorber and condenser members, of a secondary cooling system comprising condenser and evaporator. members in sealed circulatory communication with each other and.

independent of communication with the primary refrigerating system, thesaid evaporator member being in heat transfer relation with .one of the eleme'nts'of theprimary refrigerating system,

and the said secondary cooling system including rising and descending legs between its evaporator and condenser members, one thereof having a liquid seal trap, and a receiving vessel communicating therewith.

primary refrigerating system of the intermittent absorption type including generator-absorber and condenser members, of a secondary cooling'system comprising condenser and'evaporator. members in sealed circulatory communication with each other and independentof communication with the primary "'5. The combination with a primaryrefrigerating' system of the intermittentabsorption type, ihcludinggenerator-absorber and. condenser ele-135 .ments in circulatory communication with each other; of a secondary cooling system including a condenser member, two evaporator members, and a receiving vessel in circulatory-communication such that the receiving vessel collects the condeniutte and supplies it to the said evaporator members, one of said evaporator members being in heat transfer relation with the said 'g'enei htor absorber element and the other with the said condenser element. 6.1'Ihe combination with ing system of the intermittent -.absdrption type, including generator-absorber and condenser elements in circulatory communication with each other; of a secondary cooling system including a condenser member, two evaporator members, and

{receiving vessel in circulatory communication such that the receiving vessel collects the condense-to and supplies it to the said evaporator members, one of said evaporator members being a primary refrigerat relation with the said generatorabsorber element andthe other with the said condenser element, and a second receiving vessel also forming part of said secondary'cooli'ng system and communicating with a conduit leading to the condenser thereof and adapted when heated to prevent circulation through that evaporator of the secondary system which is in heat transfer relation with the generator-absorber element.

'7. The combination with sorption type refrigerating system including gen erator-absorber' and condenser. elements, of a secondary cooling system including an evaporator member in heat transfer relation with one of said elements and a condenser member communieating therewith, the said evaporator and conden'ser members being charged with volatile refrigerant and in closed communication with each other independent of the refrigerating system, heating means for the generator-absorber, and

means adapted when the heating means is turned on to evacuate the'liquid from said evaporator member,

8. The combination with-an intermittent absorption type refrigerating system including generator-absorber and condenser elements, of a secondary cooling system including an evaporator member in heat transfer relation with one of said elements and a condenser member communicat ing therewith, the said evaporator and condenser members being charged with volatile refrigerant a and in closed communication with each other independent 'of the refrigerating system, heating means for the generator-absorber, and meansadapted when the heating means isturned off to clear the gas passage in the secondary cooling system and induce circulation therein.

9. The combination with an intermittent absorption type refrigerating system including generator-absorber and condenser elements, of a secondary cooling system including an evaporator member in heat transfer relation with one of said elements and a condenser member communicating therewith, the said evaporator and, condenser members being charged with. volatile refrigerant and in closed communication with each otherindependent of the refrigerating system, heating means forthe generator-absorber, and means adapted as theheating means is turned on or off 7 respectively to" evacuate the'liquidfiom or supply liquid to the said evaporator member.

ALBERT CQ SCHICKLER.

an intermittent ab-

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