US2027058A - Method and apparatus for air conditioning - Google Patents

Description

Jam-7, 1936. A I c. R; NEESON METHOD AND APPARATUS FOR AIR CONDITIONING Jan. 7, 1936. Q NEESQN 2,027,058

METHOD AND APPARATUS FOR AIR CONDITIONING Filed Sept. 16, 1932 2 Sheets-Sheet. 2

Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE METHOD AND APPARATUS son AIR CONDITIONING s Charles R. Neeson, New Rochelle, N. Y., assignor to Baldwin Southwark Corporation, a corporation of Delaware Application September 16, 1932, Serial No. man

5 mm, (Cl. sz-u-n This invention relates to an improved method form low humidity, Moreover this stored-up hi!- and apparatus for cooling air and controlling the midity, as such a reserve might be called,,is rehumidity thereof in enclosures for people, parturned to the car usually at the most unfavorticularly in railroad cars where it is necessary able time as when passengers are opening the to contend with highly variable factors. car doors which allows admission of uncondi- 5 In air conditioning and cooling of railroad cars, tioned exterior atmosphere with all of its humidseveral well-known difliculties are encountered, ity, this accumulated natm'al and unnatural huthe principal one of which is effecting the necesmidity adding unnecessary discomfort for the sary cooling action when the train is stopped-or passengers. This system also has the disadvanrunning below a predetermined speed, it being tage that if there is very little or no excess huunderstood that while the train is travelling midity such aswhen travelling across arid lands, under normal speeds sufiicient power may be obthen the system will fail in its principal purpose tained either mechanically directly from an axle of providing a reserve. Hence it is seen that the or from an axle driven generator for operating available quantity of reserve medium is a highly the equipment. Due to the failure ofthis source variable factor which added to the inherent vaof power when the train stops or slows down beriable conditions in car cooling renders such a low a predetermined speed, various means have system objectionable. p heretofore been attempted for maintaining-the In my improved invention it is one object to cooling apparatus in operation. For instance, in provide a car cooling system having an improved so one type of cooling apparatus where a mechanimethod and apparatus forbuilding a reserve cam cal refrigeration compressor is employed, the pacity during normal running of the train for compressor is operated by an auxiliary source of use while the train is standing still and pa power such as a gasoline engine automatically ticularly for more definitely permitting the m. started when the train stops. In other cases, perature and humidity to be maintained under storage batteries have beenemployed to operate normal control and without having the reserve a the compressor. In arrangements of these kinds capacity directly depend upon or be in a position the auxiliary power sources must be relatively to aggravate an adverse condition which it is large for driving the compressor because of the desired to control. More specifically these obnecessity of immediately producing the entire re- Jects are accomplished by circulating a liquid frigeration required at any particular moment. cooling medium Such 88 water e apo ator These requirements are appreciably greater when coils of a refrigeration system and freezing a the train is standing still over when it is moving part of such water on to the surface of said coils due to the car doors being usually open with paswhile the remaining unfrozen portion of the coolsengers entering and leaving the cars with coni medium 18 uniformly Continuously cusequent large amoimt of external heat and hulated from the tank, in which theevaporator coils midity being-admitted. are disposed, through a suitable air cooling ra- Therefore it is desirable to have cooling equipdiator and back to the evaporator where it flows ment which can provide the relatively large reover the coils an i thereon. In this r it frigeration requirements when a train is stand- 5 P bl to ac s the imp v d result 01 40- ing still and yet not subject the mechanical re-'- not nly 00011118 the m y the regular r f iserafrigeration apparatus to large loads during such i1 apparatus and wit!!! i cul i system durperiods. In this respect, in another type of car in: travelling 0f e in but -1 01 il i a coolin equipment an attempt has been made to reserve supply of r frigeration such as ice and build up a reserve capacity of refrigeration by controlling more uniformly the temperature and frosting and defrosting the evaporator coils. Inhumidity of th ar- At the came time it is also asmuch as this system requires tahng air from possible to design a system for a definite reserve the car and circulating it over the evaporator apa ty in p n n ly humi i y conditions it is seen that the reserve capacity is dependent e t within e car o the exterior at o p ere upon the existence of an adverse condition which and by form i n f i e 8 l r r v ap ity it is desired to eliminate, namely, an excess can'be built up in a relatively small space due to amount of humidity. If this is removed from the larg l nt h a f cto in tran forming water air to build the reserve, it will nevertheless be rein o i 1' V166 V r ll o h zing of turned to the air at a later period when used as only a part of the liquid in the evaporator tank a reserve thus defeating at least partially, one avoids choking of the system such as would. do

useful purpose of air conditioning, namely, unlour in the event that the entireamount a: liquid in the evaporator tank was frozen. To insure that choking will not occur, the quantity of circulated cooling medium is limited to less than the total volumetric capacity of the system thus permitting the evaporator tank to be only partially filled with liquid and preferably to have the normal level of the liquid below the evaporator coils or at least to have the evaporator coils only very slightly submerged.

To obtain the best results in a system of this kind it is preferable to spray the returned cooling liquid over the evaporator coils, thus creating not only better transfer of heat from the returned liquid but also permitting more efiicient formation of ice over the evaporator cells. The ice formation may be in the nature of icicles which creates not only a large surface of reserve ref rigeration whereby sprayed watermay be quickly cooled when the train is standing still but also the icicles'will be of irregular formation around the evaporator coils or p p thus calming certain portions of the pipes to have only a thin film of ice thereon or possibly no ice at all which bare portions of the pipe would permit a higher degree of heat transfer from the flowing water during normal travelling of the train. It will of course be understood that in the event a portion of the evaporator coils ls submerged, ice may then form solidly and uniformly around such pipes but in that event the upper unsubmerged pipes will function to permit more efiicient heat transfer during normal running of the train.

Other and more specific objects and advantages will be more apparent from the following description of the accompanying drawings in which:

Fig. l is a side elevation of a railroad car diagrammatically shown as equipped with my improved cooling system;

Fig. 2 is a plan view of Fig.1;

Fig. 3 is a combined schematic and mechanical diagram of my improved system; and

Fig. 4 is a fragmentary longitudinal section of evaporator pipes with a fin construction.

In the illustrated embodiment of the invention I have shown a standard passenger railroad car I having a suitableelectrical generator 2 driven through suitable belt gearing from an axle of car wheel 3. Various types of gearing may be employed but the specific construction of such does not constitute a part of my invention. The gen- -erator supplies direct current, during running of the train, through wires 4 to a rotary converter 4' which in turn supplies alternating current through wires 5 to an electric motor 0 which drives a refrigeration compressor I pr ferably by a belt although various other types of gearing may be employed. The compressor may be of any usual type although preferably of the piston and cylinder type. The use of a rotary converter permits an alternating current compressor motor to be used thus facilitating plugging into regular supply sources at railroad stations in case it is desired to operate the compressor'for an extended period of time without relying upon the reserve capacity.

Any suitable refrigerant is compressed and discharged under high pressure through pipe 8 to a condenser 9 preferably of the air cooled type enclosed within a casing I. having an inlet H and outlet or outlets I! the condenser air being circulated by suitable fans It driven from a common electric motor I. The condenser may be of any usual form but is diagrammatically shown as comprising two headers connected with a series of pipes provided with fins. A discharge pipe I leads from the one header to a float controlled expansion valve II, this system being preferably of the flooded type. The refrigerant flows through a series of evaporator coils l1 and out to the low pressure pipe I. to the compressor 1 thus completing the refrigerating circuit. The evaporator may comprise a series of plain pipes or the pipes may be provided with a series of either annular or spiral fins or other forms of heat radiating surfaces ll whichever may be desired. 10 It will be understood from the following description that these fins not only perform the function of increasing the heat transfer surface but also of providing improved means for assisting in building up ice for reserve refrigeration capacity. The equipment so far described is supported in any suitable manner beneath the car. To effect the necessary air conditioning there is provided within the car, preferably near the vestibule roof, a radiator I! of any suitable form to which chilled water is circulated from the evaporator tank I! through pipe 2|, pump It and pipe 22 through radiator l8 and back through pipe 23 to a pipe or series of spray pipes to trickle thereover and accumulate in the bot-- so tom of evaporator casing is, the accumulated water being maintained at a liquid level 2! which preferably is below or only submerges the evaporator pipes to a limited extent.

To cool the air within the car there is pro- :5 vided an air distributing duct or ducts 21 extendlng lengthwise of the car and preferably adiacent the roof on the inside thereof or on the outside of the half deck, these air ducts bclnl provided with suitable lateral outlets into. the car. The radiator I8 is enclosed within a suitable casing 28 which has closed communication with ducts 21. .The air to be conditioned is circulated over radiator ll by a fan or fans II driven preferably by a common motor 3.. In-

' asmuch as the casing 28 has direct communication with the interior of the car it is seen that the return air from the car may pass through a suitable adjustable vaned opening ll and filter I2 and thence through the radiator it. If desired under certain circumstances a portion of the air may berecirculated, without passing through the radiator, as by the provision-of an adjustable vaned inlet 33 which will allow air to pass directly to the fans. To provide a fresh supply of air an adjustable vaned opening 34 may be placed in communication with the exterior air through a suitable passage ll provided preferably with a filter It. The various adjustablevanes may be automatically controlled by 69 usual thermostats or humidistats.

It is preferable that simple means be provided for.controlling the volume of circulated cooling liquid and to accomplish this there is provided a pipe ll for bypassing returned fluid from pipe 23 to pump 2| thereby cutting out fiuid to the sprays 25. This bypass may be suitably controlled by a thermostat or humidistat diagrammatically indicated at 4|.

In order that this system may be as self-con- 7 tained and free from difliculty aspossible there is provided in one aspect of the invention an improved automatic water make-up for the circulated cooling water comprising a pipe 31 allowing communication between a drip space below radiator II and the evaporator casing fl whereby condensate on radiator II, representing humidity removed from within the car, will flow to theevaporatortankandbeaddedtothecirculated cooling liquid thus insuring not only that proper care will be taken of any collected moisture but also of avoiding the necessity of making up evaporated liquid from the cooling system and in addition insuring that the humidity and tem perature of the air within the car may be properly controlled.

As a result of my improved combination, I am able during travelling of the train to cause a certain amount of ice 43 to be formed over the surface of the evaporator coils without completely freezing across the passageways through the evaporator thereby allowing the unfrozen water to pass through to the bottom of the evaporator tank from which it is circulated to radiator I! for cooling the car during normal travelling at thetrain. whenthetrainstopspumpil will be constantly driven by its electric motor a supplied with a small amountof electric current from the usualcar storage battery thereby to continue cooling of the car even though compressor 1 is stopped. The circulated cooling water will continue to flow over the surface of the evaporator coils and melt the ice thereon which constitutes the reserve capacity, there being no change in temperature of the water from that when the compressor is running because any e'xcess refrigeration at any given time will simply be transformed into reserve capacity. The maximum capacity can be suitably designed for any given set of travelling conditions as by adjusting the compressor capacity. It will be further seen that my improved method and apparatus will form a relatively large ice surface which-will insure maximum emciency in-the use of the reservecapacitywhenthetrainisstopped,and while the train is running the irregular formation of ice on the evaporator coils will insure accept-o able efiiciency inasmuch as the less thickly coated portions of the coils will permit the proper degree ofheattransfer. WhilethetceisshowninFigJ as, being in the nature of icicles with the lower coils less thinly coated, yet it will be understood that if desired the evaporator coils may be provided with annular or spiral fins I 1', preferably relatively clowy spaced, thus insuring a very large surface area upon which the reserve capacityoficemayfomtheiceinthismsebeing relatively thinly spread over the entire surface -thuspermittingamoreuniformrateofheat 651 transfer over the entire evaporator surface. While it is preferable that water be used other liquids might be cmp oycd but it is more efficient tousewateronacccuntoficeformingina limited space and having a high latent heat factor and also because water has high specific heat which increases its storage capacity.

From the foregoing description it is seen that I have provided an improved method for conditionlng air, especially for railway cars, consisting in operating a refrigeration system or apparatus during travelling of the car preferably by receiving its power from agene'ratcr driven by the carwhile preferably continuing the circulation of the remaining portion of the liquid which preferably only partially fills an evaporator tank to thus permit unsubmerged ice covered portions of the evaporator, whereby the frozen liquid such as ice is adapted to keep the circulating liquid chilled when the refrigeration apparatus is not in operation as when the car is stopped or running below a predetermined speed. From such a method of operation it is seen that the refrigeration apparatus preferably has a refrigeration capacity in excess of normal travelling requirements, whereby the ice may be formed on the evaporator coils even while normal cooling is being effected. The

degree of excess refrigeration may be only slight 15 or large depending upon the character of train service such as frequency of stops and length of continuous running.- In certain limited cases it may be desirable, in another aspect of the invention, to build the ice reserve capacity primarily or 20 wholly while the train is in a terminal station as by using the external source of current, but in any of these arrangements it will be seen that the re- .maining unfrozen portion of the liquid is kept circuiatin'gand that the single circulating liquid 25 In each case the medium is maintained This has the advantage that the reserve ice is to 86 a very large extent, spaced from the evaporator tank walls by an insulating air space. It will of course be understood that during winter months the radiator I. may be connected to the heating lines of the train and warm air distributed 46 through the car by use of fans 29.

In order to operate the reserve refrigeration capacity as when the train is stopped or running below a predetermined speed the circulating pump motor 88 may be supplied with current from a storage battery II which is automatically connected to the pump motor or to generator 2 in accordance with the generator voltage as by suitable voltage controlled switch mechanism used for this purpose and diagrammatically indicated at 48. If desired usual connections may be employed for simultaneously charging the battery and operating the pump motor by current supplied from the generator, but upon slowing down or stopping of the train the battery will supply current only to the pump motor to maintain continued circulation of the chilling liquid. It will also be understood that in the broad aspects of this invention the evaporator coils or pipes may be divided into sections whereby one section would serve primarily for chilled circulating liquid without an ice reserve while the other section could be used primarily or solely for building an ice reserve, this arrangement necessarily involving two expansion valves or flooded systems operating at different pressures which could be side, circulating a liquid preferably water in heat interchanging contact with the evaporator of the employed especially with a multiple effect comrefrigeration system so as to chill the liquid, causingcarairtobecooledbysaidcirculating cooled liquid. that is any air that it is desired to have cooled for the interior of the car, and then freezing-a portion of the circulated liquid preferably di t on the evaporator pipes or coils apparatus provides a very simple system and equipment for insuring constant temperature conditions of a railroad car without the need of a large auxiliary source of power for operating the refrigeration compressor when the train is standing still or when running below a predetermined speed and in addition is self-contained and economical in operation. Hence not only is the initial cost and maintenance of such auxiliary power eliminated but also less weight is added to the car.

It will of course be understood that various changes may be made in the construction and arrangement of parts and details of design without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. The method of conditioning air for railway cars consisting in operating a refrigeration system during travelling of the car, circulating liquid in heat interchanging contact with said systemsoastochilltheliquid,causingcar airtobe cooled by said circulating chilled liquid only during travelling of said car, freezing only a portion of said liquid, and circulating the remaining unfrozen portion thereof whereby the frozen liquid is adapted to keep the. circulating liquid chilled as when the caris stopped or running below a predetermined speed, the quantity of circulated cooling medium being less than the total volumetric capacity of the system.

2. An air conditioning system for railway cars comprising, in combination, a refrigeration apparatus including an evaporator, a liquid tank in which said evaporator is disposed, a radiator a for cooling the car air, and means for'circulating liquid from said tank to said radiator for cooling the, same, said refrigeration system having refrigeration capacity. in excess of that normally required during travelling of the car but adapted to cause only a portion of said circulating liquid to be congealed by said evaporator whereby when the car is stopped said radiator will be maintained cooied by continued circulation of the remaining uncongealed portion of said liquid over the congealed liquid in said evaporator, the quantity of circulated cooling medium being less than the total volumetric capacity of the system.

3. An air conditioning system for railway cars comprising, in combination, a refrigeration apparatus including an evaporator, a tank in which said evaporator is disposed, a liquid partially fllling said tank so that at least a portion of said evaporator is unsubmereed, a radiator for cooling the car air, and means for circulating said liquid from said tank to said radiator and then back to said tank to flow over said evaporator after which the liquid accumulates in the bottom of said tank for continuous recirculation, said refrigeration system having refrigeration capacity. in excess of that normally required during travelling of the car, for causingonly a portion of said circulating liquid to be frozen by said evaporator whereby when the car is stopped said radiator will be maintained cooled by continued circulation of the remaining unfrozen por- 5 tion of said liquid over the frozen liquid in said evaporator.

4. An air conditioning system for railway cars in combination, a refrigeration apparatus including an evaporator, a tank in which said evaporator is disposed, a liquid partially filling said tank so that at least a portion of said evaporator is unsubmerged, a radiator for cooling .the car air, and means for circulating said liquid from said tank to said radiator from which the liquid is returned to said tank, said circulating system including means for spraying the returned liquidover said evaporator after which the liquid accumulates in the bottom of said tank for continuous recirculation, and said refrigeration system having refrigeration capacity, in excess of that normally required during travelling of the car, for causing only a portion of said cir-- culating liquid to be frozen by said evaporator whereby when the car is stopped said radiator 2 will be maintained cooled by continued circula tion of the remaining unfrozen portion of said liquid over the frozen liquid in said evaporator.

5. An air conditioning system for railway cars comprising, in combination, a refrigeration apparatus including an evaporator, a liquid tank in which said evaporator is disposed, a radiator. means for causing air to flow over said radiator and into the interior of the car, a liquid system connecting said evaporator tank with said radiator, pumping means for eifecting said liquid circulation. said refrigeration apparatus having capacity to congeal only a portion of said circalating liquid while the remaining unconge'aled portion continues to be circulated. means for op- 4a erating said pump when said refrigeration apparatus is not in operation thereby maintaining continued circulation of the liquid and consequent cooling of the radiator by said congealed liquid, said refrigerating apparatus having 2. ca-

pacity in excess of that normally required during travelling of the car thereby to congeal only a 5 portion of said circulating liquid for use when said car is standing still, and means for bypass- I ing circulated liquid around said evaporator automatically in accordance with predetermined our air conditions, the quantity of circulated cooling medium being less than the total volumetric,ca-- pacity of the. system.

CHARLES R. NEE-SON. 56'

CEBTIFIGATE OF CORRECTION. Patent No. 2,027,058. Jequary 135 CHARLES R. NEESON.

It is hereby certified that. error appears in the Jrinted spec i 'fication of the above numbered patent requiringporrection as follows: Page 4, first,

Y-colpmn, l ine 1-7 18, claim 1, strike ou'oithe words "only during travelling of. said car". and insert the same agte'r "liquid? annbefore the cbmma. in line 19;

. and that, the said-Letters Patent should be read with this corredtion therein that the same may conform to the 15100111 of the case in the Patent Office.

Signed and sealed this 25th dayof February, A. D. 1936.

Leslie Frazer (sean I 1 Acting C ommia'sioqer of Patent-s.

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