US2598397A - Air-cooling attachment for warm air furnace systems - Google Patents

Description

S. J. LEVIN E May 27, 1952 AIR-COOLING ATTACHMENT FOR WARM AIR FURNACE SYSTEMS Filed Oct. 5, 1949 Inventor- Samuel J. Levine, y

Hus AtItOYYI ey.

Patented May 27 1952 UNITED STATES PATENT OFFICE se nue rl Lev ne-West e i.-I -a sien9 i .Qeneral- Electric Company, a corporation of ew Yor Applicationfictob'er 5, 1949, Serial No. 115M676 4 Cla m 1 The .presentinv'ention relates to acooling unit for attachmentitoa warm air iurnaceJsystem.

In general, -eoonomics indicate thatasic'omparedtothe number of. domestiefurnace installations: for winter air eonditioninathe number oiinstallations requiredior conditioning air over an entire twelve-month period are relatively small. For those home' ownersneedingorldesiring summer air conditioning, suitable air cooling" apparatus should-beprovided for use in con-' nection with existing'heating installations with the cooling means of a design such that it will not interfere withthe operation of the=heating installation but-whichear'i be operatedinconjunction therewith to provide air cooling when desired.

Accordingly, the present invention has as its prineipaiobiect the provision of a' cooling unit adapted to be added as-a-supplement toadomesticwarm airiurnaceand-to operate in con junctiontherewith to-provide a combination for year. around-air conditioningof a home.

A further object :of the present invention is to provide a; cooling. unit for summer air. conditioning which. can be employed in conjunction mth existing warm air iurnaces but which is of such, construction as-tob'e easily byepassed when not innneraiion- Another object of 1 the; invention is :to provide a 1ow-cost,:compagc t, cooling u=nit supplement for a warmai-r furnace;

.A further objec e th i ve t 1 is to provide an automatic air conditioning. installation compris eawar air r ac nd; a s pa t c o ing unitand means for controllingthe seasonal operation oi saidunits to obtain themaxirnum degree of efficieney from both.

Ad i ional obi ets and e t re .o th in e tion will become apparent from thefollowing description taken. connection with-the accen nanyin raw ng in whie he i el fleu -id grammatically illustrates the mechanical and electric l. arran em n o a e nd nine. a aratus constructed in accordance with the present intention. 7

Referring totheidrawing, there-is shown a typica1 warm .air furnace I oomprising;a;combustiofi c mber el ctr a y cont ol ed. oi

org gas; fired heating means 3 in the-combustion @emBer nd e flue 4 .fo h disch rge-oi th 2 combustion productsufromithe.eombustionchamber. Surrounding the combustion chamber 2 is an air heating chambericonnected byflmea'nsgf a return duct 6 to an enclosure il served t-bywbh furnace and. containing an. electricallyzdriven :fan

8 for-drawing air fromtheienclosure Land-pass.- ingit through the furnace1inx.heat.exchanee contact-with theoombustion chamber '2. In ,a normal operationrof .suc'h wa'rmai-r furnace, the conditioned .air is. discharged .from the chamber through vthe supp'l y portion of the duct-system tothe. enclosure :1.

In accordance with the present-invention, there is provided a-coolingunit. attachment l I adapted to be connected into the existing duct systefn of awarm air-furnace: and to operate in connection therewith. Preferably, thegcoolin g unit is connected into the downstream .of the supply portion of the warm-air-duct s'ys'temlasis shown in the drawing. The cooling unit lihasillus trated, comprises -a. .Uieshaped' cooling channel- [:2 having. an inletzlflandan outlet M: communi eating directly with-.2; passageway .15 whi'ch is connected into arid norms .part of the supply ductsystem lflsfOl thewarm-airfurnacei. :Suitably mounted within the cooling; ch-ambe'r 1:2 is a cooling chamber fan-t6 iordrawingairthrough the chamber andea cooling; unit lslpositionedin the ,path- ,of the air-flow and esuppl d with .a Suitable cooli gt ediu'mjby means of atmotordrivenomp ssor. nd evapora r system the itioned .i th 'lewervp rt of t u h th motor beingindicated by; numeral; k8.

.Means ifor' controlling the path ofjfiowof air t ou h the c ol gunit-1t! in ludes dempersfzt a apt d in their normal-position; that, is; durin the h a g. seasonw; closei-nlet l-3 andcut1et I f1.the cooling: chamber ;so; that the air-flowin from the warm air ;f -u-rnace; thy-passes. the: cooling chamber through passageway 1 5.: for summer -,air .conditioning, the campers aware raised to the dotted line position, shewninzthe drawing,= so that the-air drawntrom enclosure 1 and forced through the qcluct' .systeme passes through th'ecooling chamber lZ-where. it; is suit ably jcool'ed before :being delivered to the. en

semiautomatic: control is preferred both :froin 3 the standpoint of convenience and as will become more apparent more fully hereinafter, and in order to provide against the improper operation of the furnace and cooling unit assembly during either the heating or cooling seasons.

In the illustrated modification of the inve tion, the control system is electrically operated and comprises in part the usual electrical control system employed in connection with the operation of a typical warm air furnace. The electrical control means l9 for the heating unit 3 is connected in series with a bimetal thermostat 25 positioned within the enclosure l and a transformer 26 for providing a low-voltage current for operating the control means. Thermostat 25 includes both an enclosure heating contact 25a and an enclosure cooling contact 2512, the first-mentioned contact being connected to the circuit now being described and controlling the energization of the heating means circuit. The electrically driven furnace fan 8 is connected through supply conductors 21, 28 to a source of electrical power 29 with a thermostatoperated bonnet switch 36 connected in series with the fan driving means. The bonnet switch 30 is adapted to close the fan motor circuit only when the temperature of the air within the heating chamber exceeds a predetermined minimum temperature.

For operating the furnace in conjunction with the cooling unit attachment H, the heating means circuit is modified by the inclusion therein of a thermally operated switch mechanism 3: which is shown as including two interconnected switches 32 and 33 so arranged that only one switch may be closed at one time. The operation of these switches is controlled by a thermostat including a bulb 34 positioned outside the enclosure operatively connected to bellows 35 which by means of stem 35 controls the operation of the switches. As bulb 34 is surrounded by the outside atmosphere, switch 32 is normally closed during the heating season, i. e., when the outside temperature is at or below a predetermined maximum.

The circuits for the operation of the combined equipment during the cooling season comprise a power circuitfor the cooling unit controlled by relay 40, comprising two switches 4| and 42. The cooling chamber fan is and compressor motor I8 are serially connected through switch 4| to the power supply conductors 21 and 28, while the warm air furnace fan 8 is similarly connected to the supply conductors in series with switching means 40. Switches 41 and 42 are interconnected by and connected to the solenoid M by stem 43. By this arrangement when relay coil 46 is energized, both the warm air furnace fan 8 and the cooling unit are jointly operated in series in the air circuit during the cooling season so as to deliver the increased air flow ordinarily required for cooling purposes and to provide the increased pressure necessary to overcome the higher pressure drop as a result of the passage of air through the cooling chamber t2, the fan l6 acting as a booster in the air circulating system.

The control circuit for summer operation of the system includes switch 33 connected in series with transformer 26, with the coil is and through the high temperature contact 252; on the enclosure thermostat 25. By this arrangement, when the temperature of the outside air surrounding bulb 34 exceeds a certain predetermined temperature, switch 33 is closed and at such time as the air surrounding the room thermostat 25 also exceeds a predetermined temperature, the control circuit including these elements is energized whereby switches 4| and 42 are closed to provide for the operation of both the cooling unit and the furnace fan 8. It will be noted that both switches 32 and 33 and the switches controlled by thermostat 25 are open at temperatures intermediate those which call for the operation of the heating equipment and those which call for the operation of the cooling equipment. For example, the thermally responsive switch 3i and thermostat 25 can be so regulated that the heating circuits are energized for outdoor temperatures below 65 F. and enclosure temperatures below 70 F., while the cooling circuit is energized when outdoor temperatures exceed 1". and room temperatures exceed 75 F. At intermediate outdoor or enclosure temperatures, both circuits are de-energized.

Electrically operated means for controlling the by-passing dampers 20 comprise a solenoid 51 connected by stem 52 to the damper control lever arms 53 in such a manner that when coil 50 surrounding the solenoid is energized, the dampers are raised from their normal position to the dotted-line position to direct the air through the cooling chamber 12. The coil 50 is connected to transformer 28 through switch 33 and is in parallel with thermostat 25 and relay coil 46 so that coil 50 is energized whenever switch 33 is closed. To guard against the operation of the furnace heating means 3 at any time at which the dampers are in the raised position, there is provided in conjunction with the damper operating solenoid, a switch 54 in the heating means control circuit and operated by the solenoid so as to open that circuit when the dampers are raised to their upper or air cooling position.

The cooling unit I I is preferably connected into the downstream or supply duct system of the farm air furnace as otherwise the cool air from the cooling attachment would chill the heat transfer surfaces of the warm air furnace resulting in the unnecessary condensation thereon and in excessive corrosion of the heating unit. As the continued circulation of air through the furnace during the cooling season can result in a circulation of air downwardly through the warm air furnace fine 4 and into the combustion chamber 2, there is provided in the fine 4 a damper 51 which is adapted to be in its open position during the heatin season with the operation thereof controlled in the same manner as damper means 26 by means of a solenoid 58 and stem 68 including a coil 59 in parallel'with coil 50. Switching means 61, also operably connected to stem 60, is connected into the heating means circuit and provides against operation of the heating means 3 when the damper 5'! is closed.

From the above description, it will be seen that there has been provided a simple and inexpensive air conditioning system for use with or including an ordinary domestic warm air furnace. There has also been provided means for automatically controlling the operation of the system to obtain the maximum eficiency from both the furnace and the cooling unit attachment. During the colder seasons when the outside temperature is below a predetermined maximum, thermostat controlled switch 32 in the heating means circuit is closed and switch 33 opened. As the cooling unit control circuit is therefore doenergized, switches 54 and iii are also closed and switches 41 and 42 open so that the heating means control circuit is controlled by the operation of thermostat 25 with respect to contact 25a and the power circuit for the cooling unit is also de-energized. Whenever the outside temperature exceeds the'predetermi'ned minimum, thermostat "l operates to open switch 32 and until such time as the outside temperature approaches a temperature at which switch 33 is closed, both the heating means circuit and cooling circuits are deen'ergiedregardlessof the position of thermos'tat 25. During the summer months when. the outside temperature exceeds that at which thermostat 1 closes switch 33, the energi'z'ation or coils 5d and 59 causes damper 5 7 to close and the cooling unit dampers 2 d to open to direct the air passing through the duct system through the cooling chamber i2. As this condition maintains so long as switch 33 is closed, damper 5'1 closes the flue 4 and substantially prevents any down draft of outdoor air through the flue which would result in corrosion of the combustion chamber and the heating unit. It is to be noted that the operation of the damper 51 is independend of thermostat 25. Also, under these conditions since the heating means control circuit is open, the temperature within the warm air chamber 5 is always below that which will eiTect operation of bonnet thermostat 39 so that the furnace fan motor supply circuit including the bonnet thermostat continues to be de-energized.

Obviously the safety switches 54 and SI act, respectively, to prevent operation of the heating unit when the stack damper is closed and operation of the cooling unit when the heating unit is in operation and the cooling unit is in the heated air circuit. Either of these conditions might otherwise arise should the respective one of the dampers 57 and 20 become stuck in its actuated position and fail to return after deenergization of the actuating solenoids 5i) and 59.

Whenever, under the warm weather conditions, the temperature within the enclosure 7 reaches the point where the cooling unit control circuit including contact 25b is energized by operation of the thermostat 25, switches M and 42 are closed due to the energizati-on of coil 46 in series with contact 25b and power is supplied by these switches to both the cooling unit and to the furnace fan 8. By providing for the joint operation of fans 8 and I6 during the cooling season, the furnace fan need be no larger than would otherwise be required for normal heating purposes and the cooling unit fan need be only sufiiciently powerful to provide the increased air circulation ordinarily desired for cooling purposes and the increased pressure necessary to overcome the added pressure drop through the cooling coil. Since the cooling unit is completely bypassed during the heating seas-on, by-pass passageway I5 is in efiect merely a continuation or part of the normal air duct system for the furnace and the furnace for all practical purposes functions as a standard warm air furnace.

While certain'specific embodiments have been shown and described, it will, of course, be understood that various modifications may be made without departing from the invention. The appended claims are, therefore, intended to cover any such modifications within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a warm air furnace including an electrically controlled heating means, an air heating chamber and means including an electrically driven fa'nfor drawing air from-an enclosure through said chamber, a separate coo-1 ing unit including a cooling chamber and an elec trically driven coolingv unit fan for circulating. air through: said cooling chamber, air? conduit means connecting said cooling chamber with said heating chamberand with said enclosure, relece trically operated means for byepassing said c'ool ing chamber, and control means for comrelling the operation ofv said heating means and. said fans and said by pa'ssing means, saidcontrol means including a two-position switching means adapted to interrupt the circuit for said heating means when the outside temperature exceeds :a predetermined temperature and to interrupt the circuits controlling the operation of said cooling fan and by-passing means when the outside temperature is below a second predetermined temperature higher than the first predetermined. temperature.

2. In combination, an air heating furnace including electrically controlled heating means and an electrically driven fan operable to discharge a stream of air through said furnace, a separate cooling unit including a cooling chamber, an electrically driven discharge fan and cooling means in said chamber, means for conducting the stream of air discharged from said furnace to said cooling chamber and from said chamber to an enclosure, an air passageway in said cooling unit by-passing said cooling chamber, electrically controlled damper means for directing the flow of said air stream through said cooling unit, said damper means normally directing the air flow through said passageway, damper con trol means operable to move said damper means to a position directing the air flow through said cooling chamber, a power circuit for the heater fan, a second power circuit for the joint operation of the heater fan and cooling unit fan and cooling means, control means for controlling the operation of said heating means and fans and damper means and including an outdoor thermostat-operated switching means and an enclosure thermostat-operated switching means each adapted to interrupt the circuit for said heating means when the ambient temperatures respectively exceed predetermined minimum temperatures and to interrupt the circuits controlling the operation of the cooling unit fans and cooling means and said damper control means when the ambient temperatures are respectively below predetermined temperatures higher than said predetermined minimum temperatures.

3. An air conditioning system for heating and cooling the air in an enclosure comprising a hot air furnace having a main fan for circulating air therethrough and for discharging hot air therefrom, a conduit for conveying the discharged air to the enclosure to be conditioned, an air cooling unit having a fan for circulating air therethrough, means for by-passing the air in said conduit through said cooling unit whereby said furnace and said unit are connected in series in the path of air flowing to the enclosure, and means efiective upon operation of said by-passing means for rendering said furnace inefiective to heat the air and for maintaining both said fans in operation to circulate air to said enclosure through said cooling unit whereby said cooling fan acts as a booster for said main fan.

4. An air heating and cooling system for an enclosure comprising a heating unit and conduit means connecting said unit to supply heated air to the enclosure, a heating fan for forcing air through said unit and conduit means, a cooling unit having a fan therein for forcing air therethrough to cool the air, means for connecting said cooling unit in the path of air flowing from said heating unit through said conduit means, heating control means for said system arranged to effect operation of said heating fan and to prevent passage of air through said cooling unit, and cooling control means for said system arranged to prevent operation of said heating unit and to effect operation of both said fans andto circulate air through said heating and coolin units in series whereby said cooling fan is effective as a booster tosaid heating fan.

SAMUEL J. LEVINE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 843,909 Peters et a1 Feb. 12, 1907 1,982,305 Hunicke Nov. 27, 1934 2,001,704 Bulkeley May-21, 1935 2,011,787 Whiteley Aug. 20, 1935 2,131,295 Persons Elept. 27, 1938 2,134,498 Bailey Oct. 25, 1938 2,143,356 Miller et a1. a Jan. 10, 1939 2,238,689 Locke Apr. 15. 1941 2,474,441 Sparrow June 28, 1949 2,468,626 Graham Apr. 26, 1949

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