US2162158A

US2162158A - Air conditioning

Info

Publication number: US2162158A
Application number: US113059A
Authority: US
Inventors: Coey Stewart Clark
Original assignee: Research Corp
Current assignee: Research Corp
Priority date: 1936-11-27
Filing date: 1936-11-27
Publication date: 1939-06-13
Anticipated expiration: 1956-06-13

Description

June 13, 1939. 2,162,158

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UNITED STATES PATENT oFFicE AIR CONDITIONING Stewart Clark Coey, Glen Ridge, N. J., assigner to Research Corporation, New York, N. Y., a. corporation of New York Application November 27, 1936, Serial No. 113,059 11 claims. (ci. ca -129) This invention relates to a method and appaof circuits. The moisture-absorption-cooling l ratus for conditioning air or other gases. It is unit and the evaporative cooling unit are divided directed particularly to means whereby the facinto alike number of sections. The water cooled tors of chemical absorption, evaporative cooling in the first section of the evaporative cooler and heat exchange are utilized in a simple and where it comes in heat exchange relationship 5 effective manner to control the temperature and with the withdrawn air at its lowest wet bulb humidity conditions in a body o air or other gas. temperature is brought into heat exchange with The invention provides asystem of air conditionthe entering air in the last section of the abing involving ordinary pressures and temperasorber-cooler where it removes from the air the 1o tures therein. Refrigeration resulting from subfinal increment of heat to bring it to the desired 10 jecting vapors to cycles comprising compression dry bulb and wet bulb temperatures. and expansion is not required. The water cooled in the last section of the While air conditioning includes in its scope the evaporative cooler where it is cooled by the last removal of suspended matter and undesirable increment of available latent heat capacity of gases and vapors other than water vapor from the air leaving the system is brought into heat 15 the air, and the present invention provides for exchange relationship with entering air in the these factors to the extent required in practice, rst section of the absorber-cooler where it rethe invention is aimed primarily at the control of moves from the air the initial increment of heat. temperature and humidity conditions and will be The invention will be more particularly de- .70 more particularly described with reference to scribed with reference to the accompanying u the maintenance of the air in' an enclosure at drawings, in which: i summer comfort conditions for human beings. Fig. 1 is a diagrammatic representation of an The invention utilizes streams of a heat transair conditioning system embodying the princifer fluid, commonly water, to remove heat from ples of the invention;

, ,5 a gas to be conditioned by passing the fluid in Fig. 2 is a diagrammatic representation of one 25 indirect heat exchange relationship with the gas specic embodiment of the invention; while its moisture content is being lowered by Fig. 3 is a diagrammatic representation of a means of a moisture removing agent, and theremodified embodiment of the invention; after transferring'the heat taken up by the fluid Fig. 4 is a diagrammatic representation of anfrom the gas being conditioned to gas leaving the other modification of the invention; 30 conditioned space in the form of latent heat by Fig. 5 is a heat flow diagram illustrating the evaporatively cooling a fluid by direct contact principles of the invention; with the gas leaving the conditioned space. The Fig. 6 is a heat flow diagram illustrating the lowering of the wet bulb temperature of the gas principles of the invention under different condi- ;5 may be effected in a variety of Ways, as for extions of operation from those of Fig. 5; and 35 ample, by contacting the gas with a moisture Fig. `7 is a diagrammatic representation of a,

absorbing fluid such as a solution of calcium,l further specific embodiment of the invention. chloride, lithium chloride, sulphuric acid, phos- In the diagrammatic representation of the inphoric acid or the like, or by contacting the gas vention shown in Fig. l, the air to be conditioned with solid moisture absorbingagents, such as iS passed through a COIlditiOrlIlg unit A and ntO solid calciumchloride, silica gel or activated the space to be conditioned by means of fan M, alumina. The removal of heat from the gas by and is drawn out of the air conditioned space the heat transfer fluid may be eifected by using and through heat exchanger B by means of fan the heat transfer fluid to cool the moisture ab- N.l Cooling water is circulated` through condisorbing agent, or to cool the gas during or suctioning unit A and heat exchanger B by means ceeding the moisture absorption, or to transfer of pump O. In conditioning unit A the air is the heat from the gas in part by cooling the subjected to the action of means for removing moisture absorbing agentl and in part by cooling moisture whereby its dew point is lowered. As the gas itself. In each case the heat exchange stated above, the removal of moisture may be ,-,0 between the gas and the heat transfer medium is effected by means of liquid or solid moisture indirect in the sense that the gas and the heat absorbing agents with which the air is brought transfer medium do not come into direct coninto direct contact. Heat is removed from the tact, l air in the conditioning operation by indirect heat In a preferred embodiment of the invention exchange with the circulating water. This may the heat transfer uid is divided into a plurality be effected, for example, by contacting the moisture removing means, or the air itself, or both, with the heat exchanger P through which the cooling water is circulated.

In heat exchange unit B the water is cooled by the evaporative cooling effect of the air coming from the air conditioned space in direct contact with all or afportion of thecirculating water and/or in direct contact with a stream of water which is in heat exchange relationship with the circulating water.

In this manner the latent heat capacity of the air leaving the conditioned space is utilized for cooling, by indirect heat exchange, the air passing to the conditioned space, whereby the dry bulb temperature of the entering air may be reduced to a temperature approaching, within the limits of effective heat exchange differentials, the wet bulb temperature of the leaving air, with a minimum loss of water by evaporation.

In the specific embodiment shown in Fig. 2, the conditioning unit A includes the finned cooling coils A1 and A2, and the heat exchange unit -B is in the form of an evaporative cooler, including nned coils B1 and B2.

Atmospheric air is drawn into conditioner A at I, by means of fan 2 which blows the conditioned air leaving A into the space to be airconditioned through conduit 3. Air in equiva-v lent amount is withdrawn from the air conditioned space through conduit 4 by means of fan 5 which causes the air to pass successively over thc lower part of coil B1, the upper` part of coil and coil B2 and thence tothe atmosphere through 6.

In passing over coils A2 and A1 in conditioner A the air is dehumidifed by the absorption of moisture by means of deliquescent liquid, such as, for example, a solution of calcium chloride, lithium chloride or the like flowing down over the coils in direct contact with the air. moisture absorbing liquid is collected in sump I and is continuously recirculated over the coils by means of pump 8. At the same time the sensible heat of the air is reduced and the latent heat of absorption removed by means of the coolant liquid circulating in the interior of coils A2 and A1.

The moisture absorbing agent may be maintained at the proper concentration by recirculating at least a part of it through concentrator C, wherein it is caused to flow over a finned heating coil 9 and a stream of air is blown over it by fan Ill. The supply of steam or other heating medium to coil 9 is regulated by means of valve II which is controlled by humidostat I2 in conduit 3. By suitably setting the humidostat the concentration of the moisture absorbent can be maintained at such a point as to reduce the humidity content of the air to any desired constant amount, for example, 40% relative humidity.

The particular moisture absorbing agent and the particular method of reconcentrating it described aboveare purely illustrative and other dehumidifying agents and other means for maintaining the moisture absorptive properties of such agents may be substituted.

The absorption of heat necessary to bring the air to the desired dry bulb temperature is effected in conditioner A by means of cooling fluid, such as water, circulated through coils A1 and Az. This cooling medium cools the air indirectly by the absorption of the necessary amount of heat from the moisture absorption medium flowing over the outside of the coils.

Thel

'I'he heat absorbed by the cooling medium circulating through coils A1 and A2 is transferred in cooler B to the air withdrawn from the conditioned space. 'Ihe air is still necessarily of an effective wet bulb temperature substantially low- 5 er than its dry bulb temperature and can therefore absorb a considerable amount of heat, as latent heat. This transfer of heat to the outgoing air in the form of latent heat is effected in the embodiment of Fig. 2 by an evaporative 10 cooling operation. In this operation the coolant liquid is cooled, either directly or indirectly, by the evaporation of water in direct contact with the air. For example, the whole amount of water to be cooled may be brought, in an extended surface condition, into direct contact with the outgoing air. The contact is maintained to the extent necessary to bring the air to substantial saturation or to such lower degree of saturation as is economically justified.

In the system shown in Fig. 2, the cooling is effected by direct evaporative contact of the air with a portion of the water flowing over the` outside of finned coils B1 and B2 which in turn absorb heat from a further portion of the water flowing inside the tubes thereby lowering lts temperature.

The effectiveness of the system is increased by circulating the cooling water in two separate circuits. The water in one circuit is subjected to the cooling effect of the outgoing air at its lowest wet bulb temperature in coil B1, wherein its temperature is brought by means of the evaporative cooling of the Water flowing outside the coils to nearly the wet bulb temperature of the air entering the cooler. This water is circulated by means of pump to coil A1 oi the conditioning unit where it brings the dry bulb temperature of the air down to the desired point.

The water in the other circuit is brought into 0 indirect heat exchange, in coil B2, with water flowing over the outside of the coil and being evaporatively cooled by the residual latent heat capacity of the outgoing air coming from coil B1. The water cooled to an intermediate temperature in coil B2 is circulated by pump I4 to coil A2 of conditioner A where it serves to absorb a primary increment of heat from the absorption agent in contact with the incoming air.

It will be seen, therefore, that in this embodir ment of the invention successive increments of heat absorbed from the incoming air are successively transferred 'in inverse order to the outgoing air, or, in other Words, successive increments of temperature drop-obtained by the evaporative cooling effect of the latent heat capacity of the outgoing air are successively transferred to the incoming air. In this way the over-al1 temperature drop obtainable without the use of refrigeration is substantially increased.

That portion of the water in cooler B which is caused to flow over the outside of the coils is advantageously withdrawn'from the lowest temperature circuit and carried to the top of the cooler by pipe I5 as shown in Fig.v 2. In this case both the external stream of water and the water flowing through coil B1 are collected in sump I6, whence it is withdrawn by pump I3. The make-up water necessarily supplied to the system to replace the relatively small amount evaporated in cooler B may be supplied to the sump I6 through fioat valve I1. 'I'his has the advantage that when the water available from the mains is at a lower temperature than that of the circulating Water the make-up water tends to further lower the temperature oi thewater in the low temperature circuit.

It is also possible to maintain the water circulating circuit or circuits between cooler B and conditioner A entirely closed, and continuously recirculate a separate body of water over the outside of the coils in the cooler, adding to this, of course, the necessary amount of make-up water to replace that evaporated.

The embodiment of the invention shown in Fig. 3 likewise includes an air conditioner E, with finned coils E1 and E2, and an evaporative cooler F, with finned coils Fi and Fa.

Air entering the system at iii is drawn by ian 2t successively. over coils Ei and E1, then out through spray eliminator -22 and through conduit 2li to the space .to be conditioned.

Air from the conditioned space is drawn by ian 2b through conduit tu into cooler F, where it passes successively over coils Fi and Fa and through outlet 21 to the atmosphere.

The moisture absorbing agent is pumped successively over coils E1 and E2 by means oi pump 2t. Its concentration is maintained at the riesired point by means of concentrator D wherein medium withdrawn from the system by conduit 29 is passed through iinned coils 3@ and then sprayed through distributor 3i over 4iinned coil 32. Increase in air flow over coilii by fan 3i increases the rate of evaporation of water from .the absorbing agent.V The heated concentrated absorbing agent flows from coil 32 over the outside of coil 39 Where it is cooled by the agent flowing to the concentrator and at the same time preheat's the iinflowing absorbing agent. The concentrated agent is returned to sump 34 of conditioning unit E through conduit 35.

The low temperature coolant circuit in this embodiment includes coil F1, distributor 36, sump 31, pump 3b, coil E1, and coil 39. Coil 3u is situated in the sump of'conditioning unit E and removes a further amount of heat from the moisture absorbing agent before it is4 circulated over the coils E1 and Ez.

The higher temperature coolant circuit, which utilizes `the last increment of latent heat capacity of the outgoing air and transfers to it the rst increment of heat absorbed from the incoming air, includes coil F2, pump 4U and coil E2.

When the latent heat capacity of the outgoing air is not entirely suiiicient to bring the cooling water down to the necessary temperature to attain the desired temperature conditions in the air condition space, an additional cooling effect may be obtained by drawing a quantity of atmospheric air or air whose wet bulb temperature has been lowered by artificial means through cooler F. This is advantageously effected by admitting the desired amount of air into the cooler through conduit di and causing it to pass over coil F2.

It may under some circumstances be advantageous to obtain a portion of the desired cooling by utilizing the evaporative cooling effect of atmospheric air', for example, by circulating a portion of the cooling water through an evaporative cooling tower through which atmospheric air is passed, or by passing a certain amount of air through the Vsame cooling tower with the air leaving the conditioned space. l

The embodiment oi the invention shown in Fig. 4 illustrates the use of a solid agent lfor the removal of moisture from the air.

The air conditioning unit G includes heat exarcaica circuit.

`upper portion of change members G1 and G2, shown as finned coils. A solid moisture adsorbing agent 5i, such as lump calcium chloride, silica gel, activated alumina and the like, is maintained in the conditioning unit adjacent or surrounding the heat exchange members. The rest of the system is shown by way of example as being identical with the corresponding portion of Fig. 2, the same reference characters being used for corresponding elements.

Air drawn through louvres ,di by means ci. fan it is brought into contact with the moisture absorbing agent ti. The latent and sensible heat or the air are removed in successive increments by indirect heat exchange with the cooling water in heat exchange members Gi and G2. The water supplied to heat exchange members Gn and G2 is cooled in cooler F to successively lower temperatures by the evaporative cooling effect ci the air leaving the conditioned space as is explained more fully in connection with the preceding figures.

in the embodiment of the invention shown in Fig. 7, the cooling liquid circuits are maintained more entirely independent than in the embodi ment of Fig. 2, for example, While the moisture absorbing agent in the conditioning unit is fully countercurrent to the flow oi cooling liquid. In the embodiment of Fig. '1, the airl conditicning unit H includes iinned cooling coils H1 and H2, which form part of circuits through which cooling water is circulated between coil H1 and coils J i vand Jg oi evaporative cooling tower J, and between coil H2 and coils J3 and J4 of the evaporative cooling tower.

Air is drawn into conditioner H at 1l by means of fan 12 which blows the conditioned air leaving H into the space to be air conditioned through conduit 13. Air in equivalent amount is drawn from the air-conditioned space through conduit M by means of ian 15 which causes the air to pass successively over coils J1, J2, J3 and J4 and thence to the atmosphere through spray eliminatcr 16. The moisture absorbing agent is sprayed over coils H1 and Hz in a direction countercurrent to the ow of cooling water and concurrent to the flow of air over the coils and is collected in 4sump 11. The moisture absorbing agent is maintained at the proper concentration by circulating at least a portion of it through concentrator K wherein it first passes through coil 1B in the collecting sump 19 of the concentrator where it removes a portion of the heat content of the liquid in the sump. The absorbent then passes through coil 80 where it is further warmed by heat exchange with the air and vapor leaving the evaporator and is sprayed out of sprayer 81. It then passes successively over packing material 82, for example, Raschig Rings, steam coil 83 and packing material 84 and thence into collecting sump 19,

The heat absorbed in H1 and Hz is transferred in cooler J to the air withdrawn from the conditioned space. This transfer takes place at two separate temperature levels in the lower and upper portion of the cooling tower, respectively. A portion of the cooling water from coil H1 is passed successively through coils J2 and Jr, while the other portion of the water is caused to flow over the outside of the coils from distributor 85. Both portions of the water are collected in sump 86 and returned to the The water from coil H2 is similarly passed through and over coils J4 and J3 in the the tower, the external flow of flow of the cooling Water in coils water being distributed at 81 and both portions of the water being collected at 88.

By this method of operation it is possible to cool the water in the circuit supplying coil H1 to a somewhat lower temperature than when all of the water iiowing over the outside of the coils is derived from the low temperature circuit, as shown in Figs. 2, 3 and 4, while a more eflicient cooling and dehumidifying effect is obtained by circulating the moisture absorbing agent countercurrent to the fiow of the cooling liquid in the conditioning unit.

Figs. 5 and 6 diagrammatically illustrate the heat fiow and temperature levels in an embodiment of the invention in which the heat transfer medium is comprised in two circuits.

In Figs. 5 and 6, conditions in the conditioner unit are shown on the left and conditions in the evaporative cooler are shown on the right of the figures. The passage of the fluids through these heat exchange devices is measured, in relation to distance or time, or both, horizontally across the diagrams, although no numerical values are shown. Temperatures may be read off the vertical scale at the left of the figures. The diagonal lines indicate temperature changes in the fluids as they pass through the heat exchangers.

In the absorber-conditioner, all heat absorbed from the air. either as latent heat or sensible heat, is finally transferred through the walls of the heat exchange members to the cooling water as sensible heat and the critical values in this exchanger are the dry bulb temperatures. In the evaporatlvecooler, where at least a portion of the cooling water is in direct contact withthe air. the cooling water can be cooled only to the wet bulb temperature of the air as a limit and the wet bulb temperatures are the critical temperatures in the.evaporative cooler.

In the diagram of Fig. 5, atmospheric air enters the-system at 95 F. dry bulb, 75 F. wet bulb, and 67 F. dewpoint. In the rst stage of conditioning the air is cooled to 85 F. dry bulb and the wet bulb temperature is reduced to about 67 F., the cooling water in circuit No. 2 entering this stage at 81 F. and leaving at 84.5 F. In the next stage the air is cooled to the desired dry bulb temperature of 75 F. and wet bulb temperature of'60 F., the cooling water in circuit No. I entering this stage at 71 F. and leaving at 74.5 F.

In passing through the air-conditioned space the air attains a wet bulb temperature of 66 F. at which condition it enters the evaporative cooler. In the first stage of the cooler, temperature of the water in circuit No. `I is decreased from 74.5 to 71 F., while the wet bulb temperature of the air is increased to 73 F. In the second stage thewater temperature in circuit No. 2 is decreased from"8,4.5 F. to 81 F., the wet bulb temperature of the air increasing to 79.5 F.

'I'he shaded areas Hai and Haz between the dry bulb temperature line u, and the lines ji and 7': indicating the temperature changes in the cooling water in circuit i and circuit 2, respectively, represent the amount of heat transferred passing through the evaporative cooler. The vertical distances between the temperature lines to be that at z,

represent temperature gradients and the greater the gradient the greater will be the amount of heat transferred to or from a given amount of water with a given heat transfer surface. The vertical arrows indicate the direction of heat flow.

'Ihe areas on the right do not correspond with the areas on the left of Figs. 5 and 6 in part because of the lfact that the air as it leaves the conditioned space and enters the evaporative cooler has a considerably higher wet bulb temperature than it had when leaving the absorbereffect of the heat received by the air in passing through lthe conditioned space upon the performance of the evaporative cooler, which heat is carried to atmosphere by the air in addition to the by areas Hei and Hez, given up to the air by the cooling water as the air passes through the evaporative cooler.

'I'he temperatures and areas shown on the graphs are values selected from data obtained with apparatus ofhthe character described and represent practice wherein space, cooling surfaces, water and power are used economically.

and slope 71, if the air is to be conditioned to the desired dry bulb temperature of, say, 75. The heat removed is equal in amount to that removed by the two circuits, but with the single circuit less heat is delivered to the air near the air exit end of the coolerarea H62 becomes less-because of the lower temperature gradients existing between entrance of thecooler-area Hei is increased as in temperature gradient there when a single water stream is used.

If conditions were chosen so a single stream of water was cooled to a minimum temperature of 71 in the cooler and it was cooled along line g1, the initial temperature of this water would have or 78, an impossible condition because no heat could be transferred to the air which at that point has a wet bulb temperature of 79.5.

A similar analysis could be made of the values graphically shownv on the left side of Fig. 5 which sets forth conditions in the absorber-air conditioner unit.

Fig. 6 illustrates graphically representative results obtained when the apparatus and method of the invention are used to condition atmospheric air available at a dry bulb temperature of 81.5 AF. and a wet bulb temperature of F. These conditions provide a feeling of comfort in summer decreasedbecause of the increase i circuit under the more severe a rather small amount to most people, but they cannot be maintained in air passing through an enclosure containing people and lights and a rise of about 6 degrees in both dry bulb and wet bulb temperatures of the air passing through the conditioner space is again assumed. The absorber-conditioner unit is operated so as to remove latent and sensible heat from the air while vmaintaining it at percent relative humidity until the dry bulb temperature is '15 F. andthe wet bulb temperature is 60 Ffin anticipation of increments of heat which will be added to the air in the conditioned space.

This relatively small drop of 5 degrees in wet bulb temperature corresponds to the removal of of heat which, in turn, requires but a small amount of Water circulating in the cooling circuits or small temperature gradients across the walls of the coolers. The graphs in Fig. 6 reflect these conditions in that water temperature lines g4 and g5 are closer to` and more nearly parallel line w1 than were the corresponding lines on Fig. 5. And We now see that if the water in circuits l and 2 is combined in a single circuit and returned to the evaporative cooler at a temperature 21 (73.5 FJ, it can be cooled along line g4 to a temperature of 71 F., the temperature of the water in circuit i. However, this result could not be obtained in a single conditions of Fig. 5.

This application is a continuation-impart of my application Serial No. 73,026, filed April 6, 1936.

l claim:

l. The method which comprises bringing gas to be supplied to an enclosure into contact with a moisture aborbing agen removing heat from the gas by indirect heat exchange with a heat` transfer fluid supplying the gas to the enclosure, and thereafter contacting the gas leaving said enclosure with a stream of Water which is in heat exchange relationship fluid whereby the heat the evaporative cooling `effect of the outgoing gas,

2. The method which comprises bringing gas to be supplied to an enclosure into direct contact with a heat and moisture absorbing fluid which is in indirect heat exchange relation with a heat transfer fluid supplying the gas to the enclosure, and thereafter contacting the gas leaving said enclosure with a stream of water which is in heat exchange relationship With said heat transfer fluid whereby the heat transfer fluid is cooled by the evaporative cooling effect of the outgoing gas.

3. The method which comprises absorbing latent and sensible heat from a stream of air by contacting it with a heat and moisture absorbing fluid, while maintaining said fluid at a predetermined moisture absorptive capacity', passing said air through an enclosure, thereafter bringing said air into contact with a stream of Water in an extended surface and thereafter bringing said stream of water into heat exchange relationship with said heat and moisture absorbing fluid.

4. The vmethod which comprises contacting a stream of air .with a moisture removing agent, passing said air through an enclosure, thereafter transferring tc said air successive increments of heat from a plurality of successive streams of heat transfer fluid by evaporation` into the air of water in heat transfer relation with said streams and absorbing in said streams successive increments of heat from said stream of air before rpassing it through the enclosure.

5. The method which comprises absorbing the air with said heat transferv transfer fluid is cooled by moisture from a stream of air by contacting it with a solid moisture absorbing agent, removing heat from the air by indirect heat exchange with a heat transfer fluid, supplying the air to an enclosure and thereafter contacting the air leaving said enclosure with a stream of Water which is in heat exchange relationship with said heat transfer fluid.

6. The method-Which stream of air with a heat and moisture absorbing fluid, passing said air through an enclosure, thereafter transferring to said air successive increments of heat from a plurality of successive streams of heat transfer fluid by evaporation into of water in heat transfer relation with said streams, and absorbing in said streams successive increments of heat from said heat and moisture absorbing fluid, said streams being brought into heat transfer relation With said heat and moisture absorbing fluid in inverse order of their temperature.

1. The method which comprises bringing air to be supplied to-an enclosure into direct contact with a heat and moisture absorbing fluid which is in indirect heat exchange relationship with a plurality of successive streams of heat transfer fluid decreasing in temperature in the direction of flow of the air, supplying the air to the enclosure, and contacting the air leaving said enclosure with an extended surface of water in heat exchange relationship with said successive streams in the order of increasing temperature in the direction of flow of the air.

8. Apparatus comprising means for contacting air passing into an enclosure with an extended surface of a moisture absorbing agent, means for contacting air leaving the enclosure with an extended surface of water, and means comprising a fluid stream in indirect heat transfer relation with said moisture absorbing agent for transferring heat therefrom to said water in contact with the air.

9. Apparatus comprising means for contacting air passing into an enclosure with an extended surface of a moisture absorbing agent, means for maintaining the water absorptive capacity of said agent at a predetermined point, means for contacting air leaving the enclosure with an extended surface of water and means comprising a fluid stream in indirect heat transfer relation with said moisture absorbing agent for trans- .ferring heat therefrom to said water in contact with the air.

10. Apparatus comprising a heat and moisture absorbing chamber and an evaporative cooling chamber, means for causing a stream of air to flow successively through said absorbing chamber, an enclosure and said cooling chamber, means for contacting the air with an extended surface of a moisture absorptive agent in said absorbing chamber, means for contacting the air with an extended surface of water in said cooling chamber, and means for circulating a heat transfer fluid in heat exchange relation with said Water and in indirect heat exchange relation with the air in said absorbing chamber.

11. Apparatus comprising a heat and moisture absorbing chamber and an evaporative cooling chamber, means for causing a stream of air to flow successively through said absorbing chamber, an enclosure, and said cooling chamber, means for contacting the air with an extended surface of a moisture-absorptive agent in said absorbing chamber, means for contacting the air with an extended surface of water in said cooling comprises contacting a chamber, and means for circulating a heat transfer fluid in heat transfer relation with said absorptive agent and said water.

12. Apparatus comprising a heat and moisture absorbing chamber including'extended surface coils and-an evaporative cooling chamber providing extended surfaces, meansfor causing a flow successively through said sorbing chamber, means for causing a stream of water to flow over the extended surface in said cooling chamber and through the coils in said absorbing chamber.

13. Apparatus comprising a heat and moisture absorbing chamber including extended surface coils and cooling means including, extended evaporative surfaces, means for causing a stream of air to ilow successively through said absorbing chamber, an enclosure and said cooling means, means for effecting a circulation of moisture absorptive agent over the coils in said absorbing chamber, means for causing a stream of Water to ow over the evaporative surfaces in said cooling means, and means for maintaining at least two separate streams of heat transfer fluid in circulation between said cooling means and said absorbing chamber, that stream which is in heat transfer relation with air of lowest wet bulb temperature in the cooling means being brought into heat transfer relation with air of lowest temperature in the absorbing chamber.

14. Apparatus comprising a heat and moisture absorbing chamber including extended surface of air to flow successively through said absorbing chamber, an enclosure and said cooling means, means for effecting a, circulation of moisture abheat transfer relation with air of lowest wet bulb temperature in the cooling means being brought into heat transfer relation with air of lowest temperature in the absorbing chamber and the said absorptive agent being circulated in parallel streams in heat transfer relation with the streams of heat transfer fluid in the absorption chamber.

15. Apparatus comprising a heat and moisture v sorptive agent over the coils in absorbing chamber including extended surface coils and cooling means including extended evaporative surfaces, means for causing a stream of air to flow successively through said absorbing chamber, an enclosure and said cooling means, means for effecting a circulation of moisture absaid absorbing chamber, means for causing a stream of water to flow over the evaporative surfaces -in said cooling means, means for maintaining at least two separate streams of heat transfer fluid in circulation between said cooling means and said absorbing chamber, that stream which is in heat transfer relation with air of lowest wet bulb temperature in the brought into heat 16. Apparatus comprising a heat and moisture absorbing chamber including extended surface coils and cooling means including extended evaporative surfaces, means for causing a stream of air to flow successively through said absorbing chamber, an enclosure and said cooling means, means for effecting a circulation of moisture absorptive agent over the coils in said absorbing chamber, means for causing a stream of water to flow over the evaporative surfaces in said cooling means, and means for maintaining at least two separate streams of heat transfer uid in circulation between said cooling means and said absorbing chamber, that stream which is in heat transfer relation with air of lowest wet bulb temperature in the cooling means being brought into heat transfer relation with air of lowest temperature in the absorbing chamber and the said absorptive agent being circulated in parallel streams in countercurrent heat transfer relation with the streams of heat transfer fluid in the absorption chamber.

17.'A method of removing heat and water vapor from air which comprises passing the air in contact with a succession of extended surfaces of a moisture-removing agent, while maintaining said agent at progressively lowered temperatures in the direction of flow of the air by indirect heat exchange with a plurality of streams of heat transfer iluid which are cooled to progressively lowered temperature levels by means of successive increments of the evaporative cooling elIect of the treated air.

STEWART CLARK COEY.