US2211886A - Cooling system - Google Patents

Description

Aug. 20, 1940. w U 2,211,886

COOLING SYSTEM Filed Nov. 28, 1936 3 Sheets-Sheet l MWA TTORNEYS.

W. L. DUDLEY COOLING SYSTEM Aug. 20, 1940.

3 Sheets-Sheet 2 Filed Nov. 2a, 1936 I I INVENTOR. Mum/v A25 @0015) v ATTORNEYS.

.20.1940. w. L. DUDLEY I 2,211,886

COOLING SYSTEM Filed Nov. 28, I936 3 Sheets-Sheet 3 INVENTOR. .W/Ll./.4M [n5 01/015) Mindy?) ATTORNEYS.

Patented Aug. 20,1940

PATENT OFFICE COOLING SYSTEM William Lyle Dudley, Seattle, Wash. Application November 28, 1936, Serial No. 113,178

2 Claims.

This invention relates to cooling systems, and it has reference to improvements in systems of that kind wherein cooling is effected by means of a stream of air that is caused to flow about or through anarea to be cooled, and which stream of air, in its passage to the object orarea to be cooled is caused to flow through or across a heat interchanger, whereby its temperature is reduced for cooling, but without the addition of moisture thereto, and wherein the interchanger is cooled by the circulation of a liquid cooling medium.

therethrough.

More particularly, the present invention relates to modifications of and improvements upon the cooling systems which have been described in my copending applications, now allowed, filed on -May 13, 1935 and December '7, 1935, respectively, under Serial Nos. 21,229 and 53,364 and issued under Nos. 2,069,359 and 2,071,509.

In each of the above mentioned applications,

a stream of outside air is reduced to a cooling tem-- perature by its being'passed through a heat interchanger which, in turn, is cooled by the circulation of a'liquid medium therethrough, and the circulated medium, by evaporation, is reduced to a temperature which is sufliciently low for cooling the interchanger. The liquid medium in the devices of the applications copending is, in each instance, confined and circulated within a continuous circuit, andat one point in the circuit evaporation is induced by atomization within an evaporating chamber through which a portion of the cooled air stream is discharged to waste.

The two systems, embodied in the applications copending, are similar. In the application of e earlier filing, the incoming fresh air, or outside air, is'conducted through the heat interchanger for cooling. Then the stream of cooled air is divided, and one part of the divided stream is ing the liquid, and is then discharged to waste,

' while the other part of: the divided stream of cooled air is utilized to cool the enclosed area and to aid in the cooling of incoming outside air.

In the second of the copending applications, is disclosed a system like that of the first in that the incoming stream of outide air is divided after being cooled by passing through the heat interchanger, and one part of the cooled air stream is directed through the area to be cooled, and then is delivered back into the incoming stream of outside air. However, the other part of the cooled-air stream, after being directed through the evaporator chamber, is not delivered directly to waste, but is first conducted to a second heat interchanger which is connected in series in the circulating system of the interchanger that efiects the initial cooling and is then conducted through a cooling chamber that encloses the conduit through which outside air enters the system to initially cool this outside air, and is finally discharged to waste;

It is desired to state here that during the pendency of the earlier application above mentioned, there was submitted a disclosure later to be embodied in the second filed application, wherein a provision was made for fresh air being delivered 7 directly to the evaporator for cooling the water used in the interchanger and a split stream of fresh air was passed through the interchanger to the area to be cooled.

While there are certain advantages in each of these systems, as has been explained therein, particularly in that in neither one is any moisture added to the cooling air that passes to the area to be cooled, yet it might be considered a disadvantage in each'instance, in that the maximum cooling possible to be obtained is limited to the wet bulb temperature of the air entering the evaporator chamber. The reason for this will be understood by those familiar with the art.

In one modification of the present application, which, as has been stated, may be considered to disclose modifications of and improvements upon the systems covered by the applications previously filed, one portion of a divided air stream, or one branch of a dual air stream, is caused to traverse a heat interchanger means by which heat is extracted from the air without the addition of moisturetheretor the heat interchanger, as in the previous applications, being cooled by the circulation of a cooling liquid therethrough in a closed, continuous circuit, which, at one point, employs the evaporating chamber. The air that is cooled in this interchangeris utilized to cool the enclosed area in which it is held at a temperature less than that of the incoming outside air,'or a mixture of outside and return air, and its inside V "But, in this instance, I have inserted an auxiliary cooling means in the air conduit ahead of the is extracted from the-circulated liquid for the purpose of lowering its temperature to correspond to the point of moisture condensation of the vapor of the'contacting air, and thereby cooling I this liquid approximately to the condensation point obtained in the air entering the evaporator chamber, by reason of the auxiliary cooling means.

It is intended that the liquid used in the evaporation chamber and liquid cooling circuit; be cooled by evaporation due to direct contact between the air and an extended surface of the water in the liquid circuit, whether or not auxiliary cooling means is used. This direct contact 7 is the method of least cost, and is the method preferred rather than that requiring circulation of an auxiliary cooling liquid through the cooling circuit.

In another modification, the present invention contemplates that the cooling or outside or incoming air might be effectedby placing the auxiliary cooling means ahead of the interchanger so that indirect heat exchange takes place between the liquid of the interchanger and incoming cooled air.

The present invention further anticipates that the portion of the split or dual air streampassing to exit through the air and liquid cooling means will be cooled below the temperature of the air enclosed in the cooled area, and may be advantageously'used, if desired, to extract heat from the return or vent air from .the cooled room or from the inflowing outside air, as was disclosed in the second application, previously mentioned, by passing it in direct contact with the return circuit conduit. Also, that the vented air from the cooled room, or area, will have a temperature below that of the air entering the initial heat interchanger means, and therefore it is practicable that it be used for lcooling the incomingoutside air by lowering its wet bulb temperature and heat content, or it can be wasted outside the system under certain conditions of air temperature and moisture content. When this vented air is thus further cooled by use of cooled airfrom the air and water cooling means, it is made still more suitablefor this initial cooling of outside air. In both cases, the vent or return air is.

either reintroduced into the incoming outside air stream passing to the evaporator means or into that portion of the stream leading to the room to be cooled, and preferably before the outside entering air enters thev heat interchanger means for cooling thereby.

It will be stated further that there may be some cases where it is desirable to add moisture to the cooling air for certain processing, or the like. In such cases, water or other liquid maybe sprayed into the cooling air stream, or a conduit may be .led from the air and liquid cooling means whereby I cooled by utilizing a circulated cooling medium,

whichfin turn, is kept in cooling condition by passing a stream of air through a chamber in which the circulated liquid is atomized, and which does not require any auxiliary means for cooling the liquid so long as the wet bulb temperature of that stream of air is sufllciently low for the cooling purpose.

It is an object also to-provide-a method of 'cooling an air stream for use in cooling an enclosed area without the addition of moisture to the cooling air except as above noted, by utilizing an auxiliary means for cooling the air entering the evaporator chamber below the heat content of and to or below the temperature of moisture condensation of vapor inherent in the outside air or the air entering the evaporator chamber.

' Another object or the invention residesin the modes or methods of operation of the systems disclosed in the accompanying drawings, wherein- Fig. 1 is a view diagrammatically illustrating one modification of the system embodied by this invention.

Fig. 2 is a detail illustrating an-alternative type of heat interchanger for cooling incoming outside air that passes to the area to be cooled.

Fig. 3 is a view diagrammatically illustrating an alternative arrangement of the cooling system.

Figs. 4, 5 and 6, respectively, are details showing alternative positions for the location of the auxiliary coolingmeans.

Fig. 7 is a view diagrammatically illustrating still another modification of the system.

Fig. 8 is a detail illustrating use of an auxiliary cooling means for cooling the circulated liquid used in the heat interchanger.

Referring more in detail to the drawings--- In Fig. 1, an enclosed area to be cooled is designated at I, and at 2 is designated a conduit for the conduction of outside or fresh air to the cooling system. This conduit 2 supplies outside or fresh air to branch conduits I and l and a damper 5 is arranged at the junction of the conduits and is adjustable for the proportioning of the relative amounts of air passing to these branch conduits.

The branch conduit 4 discharges its air stream into the area i to be cooled, but interposed in this conduit is a heat interchanger i which is of a type designed to be cooled by the circulation of a liquid cooling medium within it. 'The air inilowing through the conduit 4 engages or flows through the heat interchanger, and its temperature is thereby reduced for cooling the area I.

Air is 'vented from the area I into a return conduit 8 which leads to branch conduits I and ll whereby this return, or vent air, is discharged chamber H, in the bottom of which is a sump ll The interchanger 6 in this instance comprises a series of pipe coils through which a liquid cooling medium is circulated. In the present instance, a pump i3 is the circulating means and is connected, atone side, by means of a pipe I with the sump and at the other side is connected by a pipe IS with one end of the coil 8. The other end of the coil is connected by means of a pipe I 6 to a header IT, in the chamber I2, equipped with a plurality of liquid atomizing or spray heads I8. Operation of the pump effects a forced circulation of the cooling medium from the sump,

through the coils 6 and back to the atomizing heads where it is discharged into the chambercation mentioned, air that is delivered through the evaporating chamber is utilized for cooling. It is conducted through a conduit 20 into a housing 2I which surrounds a portion of the return air conduit 8. Thus the cooled air from the evaporator chamber, by contact with conduit 8, further reduces the temperature of the return or vent air which is delivered back into the conduit 4 and into the conduit 3 or said housing 2| may be utilized to cool the incoming fresh air.

As a special feature of the present invention, I utilize an auxiliary cooling means for lowering the temperature of the incoming fresh air delivered to the vaporizing chamber and to thus efiect additional cooling of the circulated medium for the coils 6. This auxiliary means may be any suitable kind of cooling device, either mechanical,-

electrical or otherwise, but in the present instance it has been illustrated, in Fig. l, merely as the conventional cooling coil 25.

To induce a flow of air through'the area to be cooled and through the evaporator chamber, fans of suitable kind are located preferably in conduits 4 and 20. Such fans are designated at 26 and 21 and the flow of air isin the direction of the arrows as shown therein.

Assuming the system to be constructed as in.

the chamber extracts heat from the water, or

other liquid, that is employed, and thus the interchanger coils 6 are kept at a desired cooling temperature.

In the event that no artificial or auxiliary means 25 is employed in the air conduit leading to the evaporator chamber, or at any other location, the limit to which the temperature of the circulated liquid medium may be brought will correspond to the wet bulb temperature of the incoming air to the evaporator. However, by using the auxiliary means 25 and thus reducing 'the wet bulb temperature artificially, then the circulated liquid medium may be further reduced in temperature accordingly. Also, by cooling the return air in conduit 8 by passing it through the housing 2 I, an additional cooling effect is produced both in the outside air introduced to the cooled area, and also to the air passing to the vaporizing chamber, and this is advantageous and the air from chamber l2 can be used in this way even though the auxiliary means 25 is not employed.

I have provided also, in the conduit 8, an outlet 29 adjacent which is a damper 30 that is adjustable to positions to effect a partial or entire discharge of vented air through this outlet or to cause all to be returned to the system. In Fig. 2 has been shown an alternative arrangement of heat interchanger for air passing to area I. In this illustration, two coils 6a and 6b are employed, and thesehave suitable pipe connections 3| and 32, and control valves 33 and 33" whereby they may be individually used, or connected in parallel or in series, thus to selectitvely obtain a plurality of cooling efiects.

In the disclosure of Fig. 3, the arrangement is somewhat different from that of Fig. 1, but the same general principle prevails. The outside, or

fresh air is supplied to the systemthrough a conduit 2a,, and is delivered from this conduit into the enclosed area Ia that is to ,be cooled. A heat interchanger 6c is located in conduit 2a to cool vented air from the area Ia enters the chamber 36 and mixes with cooled fresh air delivered from the passage 35. The chamber 36 has an outlet 39 through which the mixture of air discharges into an evaporating chamber I2a, but there is an auxiliary cooling means, as indicated at 39, through which this mixture of air may pass for further cooling before it enters the evaporator chamber. An exhaust fan 40 operates in a housing M to draw the'air from the chamber 36. through the evaporator chamber and to discharge it from housing M to waste. is provided in chamber 36 for. admitting outside air.

Also, a part of the vented air from the area la is conducted through a return conduit 42 back into the conduit 20!. and is returned again into thesystem ahead of the interchanger Iic. To effect this flow of air, a fan of a suitable kind 43 is interposed in the conduit 42, as indicated.

In Fig. 4, I have illustrated an alternative ar-- I auxiliary cooling coil 39?) is located at the inside of the -interchanger. Still another point of location for the auxiliary cooling coil is shown in Fig. 6 wherein the coil. 390 is shown as being located in the outlet 31 from the cooled area.

Also, it will be mentioned here that in this instance, the liquid cooling medium that is used in the interchanger coils 6c is circulated by means of a pump I3a which connects with spray heads IBa provided in the evaporator chamber I2a, and also that the interchanger coil 60 has its opposite ends connected by conduits I40. and I5a, respectively, with opposite sides of the circulating In Fig. '7, the enclosed area that is to be cooled is designated at lb, and outside fresh air is delivered to the system through a. conduitto effect a forced delivery of this entering air through a duct 5I to the top of the area that is enclosed. A dampered outlet, at 52 is provided in the lower A damper 36a also area lb for exhausting air from the enclosed area to atmosphere.

The heat interchanger coil id, in this instance,-

is located at the discharge side of the fan 50 to to the enclosed area. A part of this cooled air, as was previously stated, passes through the conduit to the'area to be cooled, and the remaining part is delivered through a duct 60 into a mixing chamber 6 I, which, in turn, connects with an evaporator chamber or cooling chamber I20. An-auxiliary cooling means 65 is located at the air entrance side of the chamber lid to further cool this incoming air entering from chamber H. It will be noted also that the chamber 6 I besides being supplied with air from the duct 60 is provided with outside. air through an inlet at 68, which may be damper controlled to regulate the proportionate amounts of air supplied from the outside and from the duct 60. A fan 1! connects with the chamber In to draw air from the system, and through the cooling chamber.

It will be mentioned also that in this instance, the heat interchanger id is supplied by the cooling liquid collected in the sump of the evaporator chamber and delivered to the coils through suitable pipe connections under the influence ,of a pump or other suitable means. It will be mentioned also that in this case, the auxiliary cooling means might be independent of, or connected with the circulating system for the heat interchanger. as was previously disclosed.

In further commenting on the various modifications of the present system, it will be stated that it is apparent one or more than one air and water cooling means may be utilized in locations where structural and building arrangement make it possible, or when processing makes it desirable, or neceSSary, or where the availability of a source of cold water, having a temperature below the point at which condensation'of moisture or vapor in theair takes place,'may be suilicient and suitable to make unnecessary all, or part cool the incoming outside air before it is delivered of the auxiliary cooling means. In all cases, the

air and water cooling means may be understood to provide for cooling by air passing over the surface of a liquid, or its extended surface,rw hich extended liquid may be atomized or broken into drops or spray with which liquid, air or gas contacts, thereby causing a heat exchange between the air or gas and the liquid.

The auxiliary cooling means mentioned, as was stated, may be any mechanical,chemical,electrical or other means ofreducing the temperature of the air and/or liquid to or below the point of moisture condensation in the air passingv such means. For some conditions, where extreme accuracy or moisture control is necessary, a lower moisture condensation point in t e system may be in such a relation to the mo ture r vapor condensation point in the cooled space or room,

water temperature control means is to be utiliied,

if desired, tov operate dampers in the system, or

ters Patent is:

to bring on, or shut oil, the surface air or gas cooling means shown.

Cooling of air and liquid in and by the air and liquid cooling means takes place by steps; i. e., from one heat level to a lower one. As cooling of the air takes place by evaporative processes as described, the air and liquid will assume one heat level defined and determined by the wet bulb temperature of the air passing the evaporative cooling means and without the use oi the auxiliary cooling means of larger capacity with investment and operating costs necessary to bring the air to usual wet bulb level. Then, should further cooling of the air and/or water below this wet bulb temperature of air be necessary or desirable, it is accomplished by bringing into use the auxiliary cooling means of lesser capacity shown and described. This might be automatically effected by any suitable control means as previously suggested.

As disclosed in co-pending application Serial No. 21,229, Patent No. 2,071,509, the water cooling may be done in a double spray chamber, or stage type of evaporator in which the cooling eflect is greater due to the greater time or length of contact between air and liquid. Such an evaporator apparatus is designated as multi-stage. Particularly is the greater cooling eflect true when the temperature of the liquid is held constant in each stage, the wet bulb temperature of the air passing in contact with the extended surface of the liquid varying consecutively in each stage.

In some sections of the country, climatic conditions may at times be such that the heat and moisture content of the outside air of comparatively high relative humidity, makes the use of the auxiliary cooling means undesirable or unnecessary for the maintenance of desired inside air condition in the cooled space. Under such conditions, the auxiliary cooling means may be dispensed with when the cooling by the evaporation process described is suflicient for the in-,

side air conditions to bemaintained. Also, outside and inside air conditions may make it advisabl e to waste the exit return air from the ,of circulated liquid below that possible by evaporation. and thereby to lower it beldw the wet bulb temperature of entering air.

Having thus described my invention, what I claim as new therein and desire to secure by Let- 1. A'methodof cooling an area to a point approximating a wet bulb temperature above the temperature of moisture condensation, comprising causing a'stream of outside air to flow through a heat interchanger means, maintaining said interchanger means in air cooling condition by the circulation therethrough of a liquid'medium, providing means whereby, at one point of its circuit,

said liquid medium is given an extended surface I for atmospheric contact, passing a part of the air cooled by the interchanger into the area to be cooled and another part into a stream of outside air conducted into intimate contact with the extended surface of circulated liquid to cool the liquid to a degree approximating the wet bulb temperature of air leaving in exit from the interchanger.

2. The method of cooling an enclosed area comprising passing one portion of a dual or dieraporation to approximately the wet bulb temvided air stream into said area through heat in-" perature of entering air, returning cooled air terchanger means employing a circulated coolfrom the enclosedarea into said air streams and ing medium which at one point of its circuit utilizing cooled air delivered to exit from the passes through an evaporative cooling chamber, evaporating chamber for cooling said return air. 5 and passing the other portion through the said a v chamber whereby the air and water is cooled by WILIJAM LYLE DUDLEY.

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