US3008300A - Thermoelectric apparatus for heating or cooling of fluids - Google Patents

Description

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NOV. 14, 1961 3, RYAN ET AL 3,008,300

THERMOELECTRIC APPARATUS FOR HEATING OR COOLING OF FLUIDS Filed April 9, 1959 WWI" IHH .2

IN VEN TORS MATTHEW G. RYAN and ADDISON C. SHECKLER ATTORNEY THERMOELECTRIC APPARATUS FOR HEATING OR COOLING F FLUIDS MatthewG. Ryan, Dewitt, and Addison c. Shec kler,

Cato, N.Y., assignors to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed Apr. 9, 1959, Ser. No. 805,285 3 Claims. (Cl. 62-3) bustion of the fuel escapes through the exhaust stack and is unavailable for heating the water. Thermoelectr-ic elements, on the other hand, may be connected so as to produce heat at their hot junctions in excess of the energy supplied by the electrical power source by reason of the heat absorbed from ambient fluids at the cold United States Patent junctions. Furthermore, thermoelectric elements possess the advantage of being adapted to produce either heating or cooling at a particular location by merely reversing the flow of current through the elements so that a hot water heater may be designed which will serve as a source of chilled water by merely reversing the flow of current through the heater.

It is a principal object of this invention to provide an apparatus which utilizes the superior properties of thermo- 'elec-tric elements for the tempering of fluids.

It is a further object of invention to provide a thermoelectric apparatus adapted to heat fluids such as water while at the same time cooling surrounding fluids such as air.

These and other features of this invention which-will 7 become apparent by reference to the following description and appended drawings, are achieved by arr'aying a plurali-ty of thermoelectric elements axially lengthwise on the outside of a tank in a manner to provide either hot or cold junctions adjacent the tank and in heat exchange relation with the fluid in the tank. The other thermoelectric junctions are remote from the tank and in heat exchange relation with a second fluid such-as ambient air by means of a pin fin heat exchanger.

In the drawings:

FIGURE 1 is a cross sectional view of a thermoelectric fluid tempering apparatus constructed according to the instant invention; and

FIGURE 2. is a cross sectional view taken substan- ,tially on line 11-11 of FIGURE 1.

ranged transversely along the axis of the tank. Where a plurality of bafiles 16 are employed within the tank the apertures 17 may be staggered with respect to one another as shown in the drawing to provide circulation of the fluid within the tank when fluid is withdrawn therefrom.

The baflles 16 serve to divide the fluid containing compartment of tank 12 into a number of smaller compartments, the purpose of which will be more fully explained Thermoelectric heat exchange assembly 11 is shown in the drawing to comprise a plurality of thermoelectric elements 19 disposed between a plurality of jumpers 20 and 21 which in turn are sandwiched between sheets of electrical insulation 22 and 23, which may comprisea mica filled epoxy resin film. \As will be understood by those skilled in the art, thermoelectric elements 19 are of alternating P-type elements and N-type elements connected in series by jumpers 20 and 21 so that each jumper contacts one N-type element and one P-type element forming either hot or cold junctions at each jumper depending upon the direction of current flow through the thermoelectric elements. Groups of series connected thermoelectric may be connected in parallel for efficient operation if desired depending upon the voltage of the power source.

In the drawing all of the thermoelectric elements 19 are shown disposed outwardly away from axis of the tank and arrayed in an area extending axially lengthwise of the tank. The thermoelectric elements are also shown in the drawing to be connected in a row of three series connected thermoelectric elements which row is connected in series with the row next below it and so on throughout the length of the thermoelectric heat exchange assembly. Electrical conductors and 37 are connected to the 'theremoelectric elements at the ends of each series group for connection to an appropriate source of electric current.

Jumpers 20, which connect one N-type thermoelectric element to one P-type thermoelectric element in that order for a given direction of current flow, are disposed adjacent outside wall 32 of tank 12 and jumpers 21, which connect one Pty.pe element to one N-type element for the same direction of current flow, are disposed outwardly and remote from tank wall 32 with reference to the axis of the tank. It will be understood that when current flows in one direction through the thermoelectric elements that the one kind of junctions formed between the thermoelectric elements and jumpers 20 will be hot and that the other kind of junctions formed by jumpers 21 with the thermoelectric elements will be cold. If the direction of the current through the thermoelectric elements is reversed the junctions formed by jumpers 20 will be cold and those formed by jumpers 21 will be hot. I

Heat exchanger 28, which may comprise a vertically disposed air chimney, is associated with the junctions .Referring particularly (0' FIGURE ,1. :a thermoelectric fluid tempering. apparatus, such as 'a hot water heater,

is designated generally-at 10. and comprises a thermo- "ielectric heat exch'angeiassembly 11in conjunction with a tank 12 Tank 12, is shown in the drawings as having 'fa layer of insulation :13 whichsurrounds the walls of formed by jumpers 21. The air chimney heat exchange means may comprise'a pair of spaced parallel supporting plates 25and 26 between which are disposed a plurality of small'pin fins 24 of circular or other appropriate crosssection having a substantial area of surface contact with a second fluid such as air which is adapted to pass through the chimney 28. Sides 27 of supporting plate 26 may be .bent at right angles to plate 26'and thereby form the sides 33 and 34 are provided in insulation 13 to permit the nal apertured baflles 16 having apertures 17 therein arpassage of the second fluid. A pin fin is characterizedin that it generally has a length greater than its circumference. It will be understood that fluids other than may be passed through the chimney and that appropriate heat exchange means will be employed for whatever fluidis used. Likewise other types of heat e'xchangers may be employed to transfer heat atthe junctions formed by jumpers 21. V

Electrical insulation sheet 23 separates supporting plate 25 from jumpers 21 but'like insulation sheet 22 is made sufficiently thin so as not to'unduly obstruct passage of heat betweenthe first fluid in the tank andthejseeond fluid passing through the heat exchange means. 'Iff-additional heat exchange surfacewithi'n the tank is required, it may be achieved by extending a plurality of pins 29 from internal wall 31 of the tank, adjacentthe area in 3,008,390 I f I 1 T elements and the coefficient of performance of the ap j 'para'tus thereby improved;

7 form of thisinvention it will be understood-thatxithe in- 10v vention may be otherwise embodiedwvibhinjthe of which the thermoelectric elements are positioned,in-

wardly toward the tankaxis. 1

When the thermoelectric fluid tempering apparatus: of

this invention is employed as a hot Water heater, current v is passed through the semiconductor materials which comprise the thermoelectric elements in a direction such that. jumpers adjacent a wall of the tank 12 form .th'e' hot junctions and the cold junctions are formed Ill/j mpers 21 remote from the wall of the tank. Since the first fluid, such as Water in this case, contained within the tank isrin heat exchange relation with the hot junctions by:

reason of its close proximity to them it will be warmed. 3

The second fluid, such as air, which is in heat exchange relation with the cold junctions will give up a portion of its heat to the cold junctions and the energy of this heat will be electrically pumped through the thermoelectric elements and be given up to 'the watertin the tank. After the air is thereby cooled it will tend to fiow downwardly in vertical chimney 28 because of its greater density and be discharged through aperture 34in insula- 'tion 13 at the bottom of the tank. War-m air will, of course, enter aperture'33 at the top 'of the tank and circulate downwardly as it is cooled.

'If'the cold junctions of the thermoelectric elements are operated at a temperature below the dew point of the entering aperture 33, water will be condensed from the air and the air discharged through aperture '34 will consequently be dehumidified. An appropriate receptacle (not shownymay be provided for the condensate.

If the hot water heater is operated'in the basement of a home orother building-it will be seen'that the thermo- It will be understood that by reversingithe current flow through the thermoele'ctric'elements thatithe' junctions adjacent the tank wall will :become cold and that under such circumstances the thermoelectricapparatus mayr-be i "employedas a-water chiller. a a i While therehas been described and the following claims. r. e Weclaim: I f

1. A combination thermoelectric hot water heater and ambient air dehumidifier comprising a hollow .tankhaving a vertical axis and beingadapte'd to contain water to be heated, inlet means adjacent the lower end of said tank and outletrneans adjacent the'upperend of saidtanlca thermoelectric assembly comprising a plurality of dissimilar thermoelectric elements electrically connected to provide'a plurality of hot junctionsand a" plurality of cold junctions upon :the passage therethrough of an electric currentin a predetermined direction, means to pass an electric currentin a'predetermined direction through v said thermoelectric elements, ,said plurality of "hotijuncelectric fluid tempering apparatus of this invention provides a convenient means of dehumidifying the airttherein while at the same time functioning as a hot water heater.

Thermoelectric elements characteristically operate with ferential across them is small. It will be seen that, in a tank comprising a single chamber, warm water will normallycirculate freely by convection and maintain a substantially equalized water temperature throughout ,the

'greater heat pumping efiiciency if the tempenature'diftank. The'thermoelectric elements iat-the bottom of'the' V tank, where cold air is in heat exchange relation with jumpers 21, may be subjected to a greater temperature differential between their junctions than those 0f the thermoelectric elements near the top of the tank at a location where air which has entered through aperture '33 has not been substantially cooled .below ambient temperatnre.

In order to maintain a moreeven temperature difieren .tial between the junctions ofthe thermoelectric elements internal bafile plates .16 with staggered apertures 17 there 5 I V in, as previously described, may be provided. I Cold water entering inlet'pont 14 is thereby prevented from tions beinglocated adjacent and in heatexchange relation with a side wall of said tank, said plurality of cold junctions being radially spacedfrom-said plurality of hot junctions with' respect :to the ,said vertical of said prevent condensate formed by cooling o'flsaid ambient air from electrically shortcircuiting said cold junctions iin eluding relatively thin electrical finsulationmeans separat' 7 ing said cold junctions fromfsaid condensate. V

. 2. In a "thermoelectric 'hot. water "heater and ambient air dehumidifier, a hollow 'ventical tank having, an .axis I and adapted :to contain water to be heated,"inlet means adjacent a loweraxial end of said tank and outlet means adjacent an upper .axial endpf said tank, a t hermoelect-ric assembly located-adjacent an exterior wall lof said tank and insulted therefrom 'bya sheet of insulation, said thermoelectric assembly comprising a plurality of .thermoa electricelements electrically connected by a plurality of jumpers of electrically, conducting material to form other-- .moelectric junctions of a'type adapted tobeheated, and

thermoelectric junctions of a tjtpeed-apted tobeqcooled upon the passage 'therethrough of an elect-fie current in .a predetermined direction, means fto pass .an -electric current through said thermoelectric elements in a predetermined direct-ion, said junctions ofthe type to be heated being located adjacent andfin heat exch-angere'lation with said wall offsaidtank, said junctions of the be cooled beinglocated remote Irom, said wall of said tankand beingaligfid substantially'paralll to the. axis of said tanktocoolj and induce a downward unrestnictedly circulating'throughout the entire tank; "It

will be seen that the coldest water in the tank is conments'which are in heatexchange-relation-with the' co'ldest air in the air chimney and the warmest water. is adjacent those thermoelectric elements which, are in heat extained in that chamber adjacent the thermoelectric elechange relation with the warmest air in the'chimney.

more uniform temperature differential is consequently achieved across the junctions of all of the thermoelectric movement of ambient air about said thermoelectric. as-

'sembly, jsalid junctionsof; the type to be cooled being spaced fromsaidaxis of-said tank a greater distance than said junctions of the type toilbe heated, partition means in the interiorof said tank to preventfree convection of water said tank therebyto promote heat exchange between thermoelectric'junotions adjacent the lower end of said tankand therelatively cool water admitted through" said inlet adjacent the 'lower portion a of saidtank, said last named means also serving to promote heat exchange between thermoelectric junctions adjacent the upper portion of said tank and the rela- 'tively warmer water in the upper portion of said tank so as to maintain a relatively uniform temperature difference across the thermoelectric elements of said thermoelectric assembly, and heat transfer means including an extended heat transfer surface associated with said thermoelectric junctions of said type to be cooled to promote heat exchange between said last named junctions and ambient air to progressively cool the air induced downwardly below its dew point thereby condensing moisture from said air and dehumidifying it while maintaining substantially the same temperature differential across each of said thermoelectric elements to improve their performance.

3. A thermoelectric fluid tempering apparatus comprising a hollow tank having an axis and adapted to contain a fluid to be tempered, inlet means adjacent one axial end of said tank and outlet means adjacent the opposite axial end thereof, a plurality of substantially axially transverse perforated baflie means spaced along the axis of said tank, said bafile means dividing said tank into a plurality of axially aligned interior compartments having restricted communication therebetween, a thermoelectric assembly comprising a plurality of thermoelectric elements, said thermoelectric assembly extending axially along a wall of said tank, said thermoelectric elements having dissimilar thermoelectric properties and being electrically connected to form thermoelectric junctions of a type adapted to be heated and thermoelectric junctions of a type adapted to be cooled upon the passage therethrough of an electric current in a predetermined direction, junctions of one of said types being further remote from the said axis of said tank than the junctions of the other of said types to minimize direct heat transfer from the heated junctions to the cooled junctions, thermoelectric junctions of one of said types being located in heat exchange relation with said plurality of said interior compartments of said tank and the thermoelectric junctions of the other of said types being adapted for heat exchange with an ambient fluid exterior of said tank, means to pass an electric current through said thermoeleotric elements in a predetermined direction, means to promote passage of said ambient fluid .in heat exchange with said other thermoelectric junctions in a direction opposite to the flow of fluid through said tank from said inlet means to said outlet means so that a relatively uniform temperature differential may be maintained across the junctions of said thermoelectric elements thereby improving the performance of said thermoelectric fluid tempering apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 413,136 Dewey Oct. 15, 1889 420,641 Dewey Feb. 4, 1890 1,120,781 Altenkirch et a1. Dec. 15, 1914 1,818,437 Stuart Aug. 11, 1931 2,522,948 Hofimann Sept. 19, 1950 2,834,865 Coates May 13, 1958 2,870,610 Lindenblad Jan. 27, 1959 2,910,836 Karrer Nov. 3, 1959 2,919,553 Fritts Jan. 5, 1960 FOREIGN PATENTS 798,882 Great Britain July 30, 1958 1,166,596 France June 23, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,008,300 November 14 1961 Matthew G. Ryan et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 lines 22 and 23 after "thermoelectric" insert elements Signed and sealed this 10th day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,008,300 November 14 1961 Matthew G. Ryan, et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 lines 22 and 23, after "thermoelectric" insert elements Signed and sealed this 10th day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

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