CROSS REFERENCE TO RELATED APPLICATIONS

6 0 | This application claims the benefit of Provisional U.S. Patent Application No. 61/745,603, filed December 23, 2012, Provisional U.S. Patent Application No, 61/764,459, filed February 13, 2013, and Internationa! Application No. PCT US 13/40097, filed May 8, 2013, all of which are hereby incorporated by reference in their entirety.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

[0002] The present disclosure relates to an apparatus and method for heat transfer using a thermoelectric device, and, in particular, pumping heat.

2. Description of the Related Art

[0003] Space heating and cooling is the largest energy end use in homes, and water heating is the second largest energy end use in homes. Almost every household has at least one water heater, and about 10 percent of households replace their water heaters every year. Gas water heaters require a gas source, which is not always available. More than half of the water heaters are electrically powered. Most electric water heaters are inefficient and expensive to operate due to their resistive element heating design. An alternative to gas and electric heating and cooling, both for water and interiors is a heat pump-based heating and/or cooling system.

[0004| In the instance of a water heater, typical heat pumps use a compressor to pump heat from ambient air to the water. However, the choke of refrigerants for compressor heat puraps is limited by the refrigerants ⁵ critical temperature. High temperature refrigerants, such as R334A, may operate with a critical temperature of 100. degrees Celsius at 4 Bar, or R410A with a critical temperature of 70 degrees Celsius. Since the water is commonly heated to about 70 degrees Celsius, the refrigerants must be compressed at temperatures near their critical temperatures, a process that requires more energy as the critical temperature is approached. The compressor needs to compress at a significantly higher pressure for the refrigerant io change phase and results in loss of ener y efficiency, in most cases, the compressor-based heat pump water heaters are supplemented with a strip heater (resistive heater) to attain the high temperature delivery requirements of the water heater, and results m an overall decrease of system Coefficient of Performance (COP). Secondly, the variable speed compressors that can. operate at these high water delivery temperatures are too expensive. The retail price of commercially-available 50 gallon water heaters is typically US$1700, compared to only US$350 for the same capacity strip heater based product. This cost difference of almost US$1400 implies the payback period is typically over 4 years (based on DoE's ENERGY STAR estimated energy savings of approximately US$300 per year). As a result of this large difference between the initial price of a resistive heater based water heater and the heat pump water heater, the penetration rate of heat pump water heaters into the water heater market has been very low. What is needed is a cost effective heat pump that operates efficiently at the desired temperatures, such as for high hot water delivery temperatures .

BRIEF SUMMARY OF THE DISCLOSURE

{ ^" 0005 j In aspects, the present, disclosure is related to m apparatus and method for transferring heat, and, in particular, a pumping of heat using a thermoelectric generator.

{OO06| One embodiment according to the present disclosure includes a thermoelectric apparatus, the apparatus comprising: a fluid loop comprising a conduit configured to convey a fluid; a plurality of inner heat conducting layers disposed between a hot terminal and a cold terminal along an outer surface of the conduit; a plurality of fins in thermal comnrunkation with the inner heat conducting layers and ibe fluid, wherein th fluid loop is configured to deliver the fluid in a positiv temperature gradient flow direction in. a section of the conduit thai is in thermal communication with the plurality of inner heat conducting layers; a plurality of thermoelement groups disposed on the inner heat conducting layers, wherein each of the thermoelement groups comprises: a plurality of thermoelement pairs comprising an n-type thermoelement and a p-type thermoelement; a first set of metal layers disposed between one of the inner and outer heat conducting layers and the thermoelectric pairs; and a second set of metal layers disposed between i) the other of the inner and outer heat conducting layers and the n-type and p-type thermoelements of adjacent thermoelement pairs and ii) the other of the inner and outer heat conducting layers and the thermoelements in the first and last positions of the thermoelement group; wherein positions of the first and second sets of metal layers are reversed for adjacent thermoelement groups; a plurality of outer heat conducting layers disposed on the thermoelement groups and overlapping with the loner heat conducting layers, wherein the thermoelement layers are disposed in the overlaps between the inner heat conducting layers and the outer heat conducting layers; a plurality of insulation sections disposed along the outer surface of the conduit and between adjacent layers of the plurality of inner heat conducting layers; and a pluralit of gaps disposed between adjacent, outer heat conducting layers. The fluid may comprise at least one of i) water, ii) steam, in) mineral oil, and iv) terphenyl. Each of the thermoelements may comprise one or more of: i.) Bio.5Sbj.5Te5, ii)

iv) YbuMnSbu, v) MnSii.73, v.i) aC sO^ vii) B-doped Si, viii) B-doped Sio.sGeo.2, ix) Bi2 e2.sSeo.2, x) PbTe, xi) AgPbssSbTeao, xii) PbTe/SrTe- a, xiii) Ba . sY¾o9CQ4Sb ₃ ¾ xiv) Mg2Si(i. S¾«, xv) TiNiSii, xvi) SrTiO.*, xvit) -doped Si, xviii) P~doped Sio.sGCt ; ix) LasTe^ X ) CoSbi, xxi) Yb-doped CoSbs, xxii) gsSi, xxiii) CePds, and xxiv) YbAlj. ^' Bach of the thermoelements ma comprise at least one of: i) B-doped Si, it) P -doped Si, iii) CoSbs, iv) Yb- doped CoSbs, v) MgsSt, vi) CePds, and vii) YbA . The Insulation section may comprise at least one of; poly amide and parylene-HT. The inner heat conducting layers and the outer heat conducting Savers may be metal The conduit may be thermally and electrically insulated. The outer heat conducting layers, the inner heat conducting layers, and the thermoelement groups ma be configured to provide a heat path from the hot terminal to the cold terminal. The thermoelements may be one of: bulk and thin-film.

{0007| Another embodiment according to the present disclosure includes a thermoelectric apparatus, the apparatus comprising: a fluid loop comprising a conduit configured to convey a fluid; an n-type thermoelectric stack disposed between a hot terminal and a cold terminal along an outer surface of the conduit, the n-type thermoelectric stack comprising: a plurality of alternating inner heat conducting layers and insulation sections disposed along the outer surface of the conduit; and a plurality of alternating n-type thermoelements and gaps disposed on the alternating inner heat conducting layers and insulation sections, wherei the plurality of inner heat conducting layers are staggered with the plurality of n-type thermoelements to provide a partial overlap between at least one of the n-type thermoelements and two of the inner heat conducting layers; a p-type thermoelectric stack disposed between a hot terminal and a cold terminal along the outer surface of the conduit, the p-type thermoelectric stack comprising: a plurality of alternating inner heat conducting layers and insulation sections disposed along the outer surface of the conduit; and a plurality of alternating p-type thermoelements and gaps disposed on the alternating inner heat conducting layers and insulation sections, wherein the plurality of inner heat, conducting layers are staggered with the plurality of p-type thermoelements to provide a partial overlap between at least one of the p-t c thermoelements and two of the inner heat conducting layers; and a plurality of fins in thermal communication with the inner heat conducting layers and the fluid, wherein the fluid loop is configured to deliver the fluid in a positive temperature gradient .flow direction in a section of the conduit that is in thermal communication with the plurality of inner heat conducting layers. The fluid may comprise at least one of i) water, u) steam. Hi) mineral oil, and iv) terphenyl. Each of the thermoelements may comprise one or more of: i.) BiasSbtsTe*, it) iii) CeFe sCoasSbja, iv) Yb^MnSbu, v) Mn.Sij.73, vi) aCojtXj, vii) B-doped Si, viii) B-doped S o.gGeo^, tx.) xiv) Mg?Si(i,4Sno.f _JS xv) TiNiSn, xvi) SrTiOs, xvii) P-doped Si, xviii) P-doped Sio.jsGeo.j, xtx) LajTe , xx) CoSbs, xxi) Yb-doped CoSb¾, xxii) Mg?Si, xxiii) CePd.?, and xxiv) Y0AI3. Each of the thermoelements may comprise at least one of: i) B-doped Si, ii) P-doped Si, iii) CoSi¾, iv) Yb- doped CoSbj, v) MgsSi, vi) CePds, and vii) YbAi¾. The insulation section may comprise at least one of: polyaraide and parylene-HT. The inner heat conducting layers and the outer heat conducting layers may be metal. The conduit may be thermally and electrically insulated. The outer heat conducting layers, the inner heat conducting layers, and the thermoelement groups may be configured to provide a heat path from the hot terminal to the coid terminal.

fOOOSJ Another embodiment according to the present disclosure may include a thermoelectric apparatus, the apparatus comprising: a fluid loop comprising a conduit, configured to convey a fluid; an n-type thermoelectric stack disposed between a hot terminal and a cold terminal along an outer surface of the conduit, the n-type thermoelectric stack comprising; a plurality of inner heat conducting layers disposed along the outer surface of the conduit; a plurality of n-type thermoelements disposed on the inner heat conducting layers; a plurality of insulation sections. wherein the n-type thermoelements are fully overlapped by the inner heat conducting layers, and the insulation sections are disposed between adjacent inner heat conductin layers and adjacent n-type thermoelements; a plurality of outer heat conducting layers disposed on the n-type thermoelements and the insolations sections, wherein the outer heat conducting layers are staggered with the plurality of n-type thermoelements to provide a partial overlap between at least one of the outer heat conducting layers and two of the n-type thermoelements; and a plurality of gaps disposed between adjacent outer heat, conducting layers; a p-type thermoelectric stack disposed between a hot terminal and a cold terminal along the outer surface of the conduit, the p-type thermoelectric stack comprising: a plurality of inner heat conducting layers disposed along the outer surface of the conduit; a plurality of p-type thermoelements disposed- on the inner heat conducting layers; a plurality of insulation sections, wherein the p-type thermoelements are fully overlapped by the inner heat conducting layers and the insulation sections are disposed between adjacent inner heat conducting iayexs and adjacent p-type thermoelements; a plurality of outer heat conducting layers disposed on the p-type thermoelements and the insulations sections, wherein the outer heat conducting layers are staggered with the plurality of n-type thermoelements to provide a partial overlap between at least one of the outer heat conducting layers and two of the p-type thermoelements; and a plurality of gaps disposed between adjacent outer heat conducting layers; and a plurality of fins in thermal communication with the inner heat conducting layers and the fluid, wherein the fluid loop is configured to deliver the fluid in a positive temperature gradient flow direction in a section of the conduit that is in thermal communication with the plurality of inner heat conducting layers. The fluid may comprise at least one of i) water, ii) steam, Hi) mineral oil, and iv) terphenyl. Each of the thermoelements ma comprise one or more of: i) Bio Sb Tes, ii) Z¾Sbj, iii) Yb^MnSbu, v) MnS.ij.7j, vi) NaCo2( , vii) B-doped Si, viii) B-doped Si0.sGe0.2- ix) Bi2Te2.5jSeo.-2, x) PbTe, xi) AgP i8$bTe2o, xii) PbTe SrTe-Na, xiii) B o.osY ci yyCcuSbf s, xiv) xv) TiNiSn, xvi) SrTt<¾, vii) P-doped Si, xviii) P-doped 5te,§Geo.2 _> xix) La^Te^ xx) CoSbs, xxi) Yb-doped CoSb.3, xxii) MgjSi, xxiii ) CePd _¾ and xxi.v) YbAb,. Each of the thermoelements may comprise at least one of: i) B-doped Si, ii) P-doped Si, iii) CoS¾, iv) Yb-doped€oSl>¾, v) MgjSi, vi) CePt¾, and vii) YbAb. The insulation section may comprise at least one of: polyamide and pary!ene-BT. The inner heat conducting layers and the outer heat conducting layers may be metal. The conduit may be thermally and electrically insulated. The outer heat conducting layers, the inner heat conducting layers, and the thermoelement groups may be configured to provide a heat path from the hot terminal to the cold terminal.

j0009| Another embodiment according to the present disclosure includes a thermoelectric apparatus, the apparatus comprising: a fluid loop comprising a conduit configured to convey a fluid; an n-type thermoelectric stack disposed between a hot terminal and a cold terminal along an outer surface of the conduit, the n-type thermoelectric stack comprising: plurality of inner heat conducting layers disposed along the outer surface of the conduit; a plurality of insulation sections, wherein the insulation sections alternate with the inner heat conducting layers along a path between the hot terminal and the cold terminal; a plurality of n-type thermoelements disposed on the inner heat conducting layers and the insolation sections, wherein the n-type thermoelements are staggered with the n-type thermoelements to provide a partial overlap between at least one of the n-type thermoelements and two of the inner heat conducting layers; a plurality of outer heat conducting layers disposed on the n-type thermoelements and fully overlapping the n-type thermoelements; and a plurality of gaps between adjacent outer heat conducting layers and between adjacent n-type thermoelements; a p-type thermoelectric stack disposed between a hot terminal and a cold terminal along the outer surface of the conduit, the p~ typ thermoelectric stack comprising: a plurality of inner heat, conducting layers disposed along the outer surface of the conduit; a plurality of insolation sections, wherein the insulation sections alternate with the inner heat conducting layers along a path between the hot terminal and the cold terminal; plurality of p-type thermoelements disposed on the inner heat, conducting layers and the insulation sections, wherein the p-type thermoelements are staggered with the p-type thermoelemenis to provide an overlap between at least one of the p-type thermoelements and two of the inner heat conducting layers; a plurality of outer heat conducting layers disposed on the p- type thermoelemenis and fully overlapping the p-type thermoelemenis; and a pluraiiiy of gaps between adjacent outer heat conducting layers and between adjacent p-type thermoelements; and a plurality of tins in thermal communication with the inner heat conducting layers and the fluid, wherein the fluid loop is configured to deliver the fluid in a positive temperature gradient flow- direction in a section of the conduit that is in thermal communication with the pluraiiiy of inner heat conducting layers.

f00i 0| Another embodiment of the present disclosure comprises a thermoelectric apparatus, the apparatus comprising: a fluid loop comprising a conduit configured to convey a liquid metal; a thermoelectric stack disposed between a hot terminal and a cold terminal along an outer surface of the conduit, the thermoelectric stack comprising: a plurality of inner heat conducting layers disposed along the outer surface of the conduit; a plurality of thermoelement disposed on the inner heat conducting layers; a plurality of insulatio sections, wherein the thermoelemenis are fully overlapping with the inner heat conducting layers and the insulation sections are disposed between adjacent inner heat conducting layers and adjacent thermoelements; a plurality of outer hea conducting layers disposed on the thermoelements and the insulations sections, wherein the outer heat conducting layers are staggered with the plurality of thermoelements to provide a partial overlap between at least one of the outer heat conducting layers and two of the thermoelements; and a plurality of gaps disposed between adjacent outer heat conducting layers. The ermoelements are one of n-type or p-rype. The thermoelements may be selected from one or more of: i) Bio. Sbj.5Tes, ii) ZiuSb.?, lit) iv) YbuMnSbn, v) MnSit.73, vi) NaCo2<->4, vu) B-doped Si, viii) B-doped Sio.»Ge 2, ix) BisTea^Seo^. x) PbTe, xi) A Pb^SbTea , xii) PbTe/SrTe~Na, xiti) Bao. 8Y o.wC04Sb.t2, xiv) MgaSif Sno * xv) TiNiSn, xvi) SrTiOj, xvii) P-doped Si, xviii) P-doped Sie.sGeo. ₂ , xix)

xxiii) CePd _? , and xxiv) YbAl¾. Each of the thermoelements may comprise at least one of: i) B~ doped Si, ii) P-doped Si, iii) CoSb;*, iv) Yb-doped CoS¼ ₅ ) g ₂ Si„ vi) CePd _; ¾, and vii) YhAk The insulation sections may comprise at least one of; poiyamide and parylene-HT. The inner beat conducting layers and the outer heat conducting layers may be metal. The outer heat conducting layers, the inner heat conducting layers, and the thermoelement groups are configured to provide a heat path from the hot terminal to the cold terminal.

{001 ] I Examples of the more important features of the disclosure have been summarized rather broadly in order that the detai led description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0012 J For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:

FIG. I a schematic thermoelectric fluid heater according to one embodiment of the present disclosure;

FIG. 2 is a schematic of a thermoelectric fluid heater with resistive heating element according to one embodiment of the present disclosure;

FIG. 3 is a schematic of a thermoelectric fluid heater with a thermal battery according to one embodiment of the present disclosure;

FIG. 4 is a schematic of a thermoelectric fluid heater with a thermal battery with fluid loops to transport heat according to one embodiment of the present disclosure;

FIG. 5 is a schematic of a thermoelectric fluid heater with convection, induced by themtoelectric converters according to one embodiment of the present disclosure;

FIG. 6 is a schematic of a thermoelectric converter apparatus with a counter-flow fluid loop adjacent to the apparatus according to one embodiment of the present disclosure;

FIG. 7 is a schematic of a thermoelectric converter apparatus with a counter-flow fluid loo flow path through the thermoelements according to one embodiment of the present disclosure;

FIG. 8 is a 3-D perspective view of a single type thermoelemeftt stack with a counter-flow fluid through the thermoelements according to one embodiment of the present disclosure; FIG. 9 A is a schematic of an air heater using a thermoelectric converter apparatus according to one embodiment of the present disclosure;

FIG. 9B is a schematic of a water heater using a ihermoeiectric converter apparatus according to one embodiment of the present disclosure;

FIG. 10 is a schematic of a cooling system using a themioelectric converter apparatus according to one embodiment of the present disclosure;

FIG. 11 is a schematic of a thermoelectric apparatus with bulk thermoelements and a counter-ilow fluid loop configured for lateral heat conduction according to one embodiment of the present disclosure;

FIG, 12A is a schematic of a thermoelectric apparatus with thin-film -thermoelements, inner heat conducting layers and a counter-flow fluid loop configured for lateral heat conduction according to one embodiment of the present disclosure;

FI G. 12B is a close up of the heat conducting layers and thermoelement of FI G. 12A;

FIG. Ϊ3Α is a schematic of a ihermoeiectric apparatus with thin- film thermoelements, inner and outer heat conducting layers, and a counter-ilow fluid loop configured for lateral heat conduction according to one embodiment of the present disclosure;

FIG. J.3B is close up of the heat conducting layers and thermoelement of FIG. 13A;

FIG. 14A is a schematic of a thermoelectric apparatus with thin-film thermoelements, inner and outer heat conducting layers, and a counter-flow fluid loop configured for lateral heat conduction according to one embodiment of the present disclosure;

FIG. 14B is a close up of the heat conducting layers and thermoelement of FIG. 14A; FIG. 15 is a schematic of a thermoelectric apparatus with a counter-flow fluid loop configured to operate with a liquid metal as the fluid accordin to one embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

|0013| Generally, the present disclosure relates to art apparatus and method for transferring heat, and, in particular, pumping heat with a thermoelectric converter. The present disclosure is susceptible to embodiments of different forms. They are shown in the drawings, and herein will be described in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principle ^' s of the present disclosure and is not intended to limit the present disclosure to that illustrated, and described herein.

10014} The optimum COP for a thermoelectric converter for cooling operation is defined as the ratio of heat pumped from the cold side to hot side of the cooler to the input electrical power. The optimal COP is determined by the following relationship:

where T _c and T _h are the temperatures of the cold side and hot side respectively, ZT is a dimensionless parameter known as figure~of-merit, which combines the thermoelectric properties of the material, 7' _ew ^~ (7 ^' ,. + T _h }/2 and AT ~ T _k - T _t .

{0015} The heat rejected by the thermoelectric converter into the fluid (¾ depends on the input electrical power (P _e3ec ) as follows: These equations may be used to estimate the heat pump requirements for heating a fluid, such as water or air, to a. target delivery temperature.

10016} FiG. i shows a schematic of an apparatus 100 for hea ting a fluid 160 according to one embodiment of the present disclosure. The apparatus 100 may include a housing 110 designed to store the fluid 160. The fluid 160 may be a liquid or a gas. The fluid 160 may include, but is not limited to, one or more of: water, paraffin, air, and petroleum fractions. The housing 110 may include a structural layer 116, such as stainless steel or ceramic, that will not be corroded or degraded by the fluid 160. The housing 1 0 may include a tank or other structure that forms a compartment or chamber to hold the fluid 160. The housing 110 may also include thermal insulation 118. The housing 110 may include an inlet Ϊ 14 and an outlet 112 for the fluid 160 to enter and leave the housing 110. A heat transfer device 120 may be disposed in the housing 110 such thai the heat transfer device 120 is in thermal, and often physical, communication with, the fluid 160, Beat fins 122 may be attached to the heat transfer device 160 to increase the distribution of heat from the heat transfer device 120 into the fluid 160. The heat transfer device 120 may be any suitable device configured to transport heat energy including, but not limited to, one or more of: i) a heat pipe, ii) a thermosyphon, iii) a thermal diode, and iv) a heat exchanger. The heat transfer device 120 may be in thermal connection with a hot side 132 of thermoelectric convener 130. The thermoelectric converter 130 may he configured to produce a temperature differential between the hot side 132 and a cold side 134 in response to electrical power received from a power source 170. The thermoelectric converter 130 ma be a thin-film thermoelectric device. In some embodiments, the thennoeiectric converter 130 may .include multiple thermoelectric devices in parallel and/or series configuration. In some other embodiments, the thermoelectric converte 130 ma comprises of cascaded o segmented theraioelectnc devices. The thermoelectric co« verier 130 may be disposed in the housing 110 such that the hot side 132 is inside the thermal insulation 118 and the cold side 134 is outside of the thermal insulation 118, A heat transfer device 140 may be disposed in thermal communication with the cold side 134 to move heat into the cold side 134 of the thermoelectric converter from the ambient The heat transfer device 140 may include fins 142 configured to gather heat from, the ambient air. In some embodiments, the ambient air may be moved through the ins 142 by a forced air supply 150, such as a ran.

|0Q17J As would be understood by a person of ordinary skill in the art. with the benefit of the present disclosure, there may be a variety of embodiments in keeping with the design shown in FIG. 1. For example, in an aspect, of air heating, the housing 110 may be the walls, floor, and ceiling of a room that hold a volume of air to be heated. In some embodiments, the housing 110 may not be enclosing, such as in the case of a vat. In some embodiments, one or more of the heat transfer devices 120, 140 may be optional, and the tins 122, 142 may be in thermal communication with the hot and cold sides 132, 134, respectively. While the thermoelectric converter 130 is shown as singular and disposed at the bottom of the housing 110, this is exemplary and illustrative only, as there may be multiple thermoelectric converters 130 and the thermoelectric converters 130 may be disposed anywhere within the housing 110 so long as heat may be transferred between the inside and the outside of the housing 110. The thermoelectric converters 130 may be staged in series or parallel or both as desired to provide a specified heat differential or amount of heat flow between the fluid 160 and the ambient air ,

|0O18| FIG. 2 shows a. schematic of an apparatus 200 for heating a fluid 160 according to another embodiment of the present disclosure. The apparatus 200 includes the elements of apparatus 100 in FIG, 1 and, additionally, includes a resistive hearing element 210. The resistive heating element 21 may receive electricity from the power source 170 (connections between the power source and the resistive heating element not shown). The resistive heating element 210 may be configured to supplement the heat energy being provided to the fluid 160 by the tlrermoelectric converter 130. The resistive heating element 210 is configured to provide heat to the fluid 160 independently or in combination with the themioelectric converter 130. In some embodiments, the thermoelectric converter can heat and maintain the fluid 160 at a predetermined temperature and the resistive heater ca be used only when a higher fluid temperature is desired.

|<I 19| FIG. 3 shows a schematic of another apparatus 300 for heating the fluid 160 according to another embodiment of the present disclosure. The apparams 300 may include elements from apparatus 1 0 shown in FIG. 1. The apparatus 300 may include a thermal storage medium 310 that may be stored in. a housing 320. The thermal storage medinm 310 (such as a thermal battery) may include substances with high heat capacity that remain liquid in the operating temperature range of the fluid 160, including, but not limited to. one or more of: water, paraffin, and molten salts, in some embodiments, the thermal storage medium 310 may include substances suitable for a reversible exothermic chemical reaction. The ihermai storage medium 310 may be selected based o the heating temperature range selected for the desired fluid 160. The heat transfer device 140 may be in thermal communication with the thermal storage medinm 3:10. Heat may be supplied from the thermal storage medinm 3:10 through the heat transfer dev ice 140 to the cold side 134 of the thermoelectric converter 130. Another heat transfer device 330 may be disposed in thermal conrmunication with the thermal storage medinm 310 and configured to transport heat into the thermal storage medium 310. The heat transfer device 330 ma be in thermal communication with a hot side 342 of another thermoelectric converter 340. The heat transfer device 330 may include tins 332 configured to distribute heat into the thermal storage medium 310. A cold side 344 of the thermoelectric converter 340 may be n thermal communication with the ambient air to gather heat. Fins 350 in thermal commtmteation with the cold side 344 may be used to increase the surface area of ambient air to .increase heat gathering, in some embodiments, heat gathering may he increase using the forced air supply .150. The thermoelectric converter 340 may charge the thermal storage medium 310 while the thermoelectric converter 130 moves heat from the storage medium to the fluid 160. The heat transfer device 330 may be diodic in nature, which allows the heat to predominately move in one direction from the hot side 342 to the thermal storage medium 330.

[O020J FIG. 4 shows a schematic of an apparatus 400 for heating fluid 160 according to another embodiment of the present disclosure. A heat exchanger 410 may be disposed in thermal communication with the fluid 160 to convev heat into the fluid 160. The heat exchanger 410 may receive heat from a first pumped loop 420 containing a heat transfer fluid, such as water or oil. The first pumped loop 420 may be in thermal communication with a hot side 432 of a thermoelectric converter 430, which is configured to supply heat to the first pumped loop 420. A cold side 434 of the thermoelectric converter 430 may be in thermal communication with a second pumped loop 440 that is configured to transport heat to the cold side 434 from an ambient air heat exchanger 450. In some embodiments, a forced air source 460 may enhance the transfer of heat from the ambient air into the ambient air heat exchanger 450. In some embodiments, the first pumped loop 420 may circulate through thermal storage medium 310 (such as a thermal battery) via a heat exchanger loop 470. The thermal storage medium 3 0 may be configured to store or release heat into the first pumped loop 420 as is required to provide the desired temperature for the fluid 160. hi some embodiments, the housing 320 may be at least partiaily enclosed by thermal insulation 480.

(00211 Some embodiments of apparatus 400 may be configured to operate in at least three different modes, In a first mode, the thermoelectric converter 130 may move heat to th fluid 1.60. In a second mode, the themioelectric converter 130 may move heat to the thermal storage medium 310. In a third mode, the thermal storage medium 310 may be used to move heat to the fluid 160. In the third mode, the thermoelectric converter 130 and the second pumped loop may not be operating. One or more valves and/or pumps in the pumped loops 420, 440 may be configured to for performance of each of the three modes.

[0022] Although the embodiments shown above depict only a single thermoelectric heat pump, in practice the design may include multiple thermoelectric heat pumps connected thermally in parallel and electrically in series or parallel or series/parallel configuration (depending upon the desired voltage-current characteristics). Also there are many different types of heat exchangers that can be incorporated. An exemplary heat exchanger may include a counter flow configuration of fluid flow.

[0023) FIG-. 5 shows a schematic of a fluid heating apparatus 500 configured to incorporate convection induced mass flow in the fluid 1 0 to facilitate heat pumping according to one embodiment of the present disclosure. The apparatus 500 may include several elements of apparatus 100 shown in FIG. 1. An inlet conduit 514 ma be disposed, to provide the fluid 160 into the bottom of the housing 11.0. Since the incoming fluid through the conduit 514 is colder, this configuration supports natural convection in the chamber. The housing 1 10 may be at least partially partitioned by a baffle 510 to form a column 520 of the fluid 160 between the baffle 510 and a wall of the housing 110. One or more theraioeJec-tric converters 130 may be disposed in the housing 110 and configured to pump heat into the fluid 160 through heat transfer devices 1 0 and fins 122, The heat transfer devices 120 and fins 122 may be disposed in the column 120, Some fluids, such as wafer, change density with changes in temperature. The heat added to the fluid 1.60 from the heat transfer devices 120 and fins 122 will cause the local temperature of the fluid 160 to increase and induce movement in the fluid 160 due to density changes. The baffle 510 may channel this induced movement into a direction along the column 520. With multiple thermoelectric converters 130 pumping heat into heat transfer devices 1.20 and fins 1.22 in thermal communication with the column 52 , a flow (due to the changes in density of the fluid 160) may produce circulation throughout the fluid 160 within the housing 10.

[0024] in some embodiments, the heat transfer device 120 or the fins 122 may be optional. In the inlet pipe 514 is shown delivering fluid at the bottom of the baffle 510, however, this is exemplary and illustrative only, as the inlet pipe 514 may deliver fluid anywhere in the housing 110, such as at the top of the baffle 510. As one of ordinary skill in the art would understand with the benefit of the present disclosure, apparatus 500 may be modified to transfer heat out of the .fluid 160, in which case, the fluid circulation pat would be reversed as the cooled fluid would sink rather than rise. In such cases, multiple thermoelectric converters may be removing heat from the fluid 160 to the ambient (instead as pumping heat into the fluid) thus causing the coldest and the densest portions of the fluid 160 to settle in the bottom of the apparatus 110.

[0025 j A person of ordinary skill in the art with the benefit of the present disclosure would understand that by reversing the heat flow of some of the elements, the direction of heat pumping may be reversed to cause a cooling of the fluid 160. in a cooling configuration, the thermal storage medium 310 may include materials that are suitable for an appropriate temperature range for cooling the fluid 160. |ft026| In some aspects, the thermoelectric converter 130 may include its own fluid loop, herein referred to as a counter-flow fluid loop. The counter-flow fluid loop may be circulated by a mechanical or electromagnetic pump system, which may be selected based on the counter-flow fluid used in the loop. The application of the counter-flow fluid is to reduce phonon. conduction in thermoelements of the thermoelectric device, wherein counter-flow refers to a flow in the direction of a positive temperature gradient. The coupled fluid flow may alter the temperature and heat flow profiles of a thermoelectric device without affecting electron transport. This alteration may increase the efficiency of the counter-How thermoelectric devices (FLO-TEs). |<H}27| The counter-flow includes a fluid in thermal communication with the thermoelements. Suitable counter-flow fluids have good heat capacity, good thermal conductance, and low viscosity. Exemplary and non-limiting counter-flow fluids may include water, an ethylene glycol- water mixture, mineral oil, terphenyl, and liquid metal. The counter- flow fluid may be selected depending on the application of the thermoelectric de vice and other limitations, such as operating temperature ranges.

{0028) Many thermoelectric materials are selected for their high ZT values, where ZT - / , and o6' ^" is referred to as the power factor of the themioeleciric material, while

X is the thermal conductivity of the material. Thus, in order to have a high ZT, typical thermoelectric materials must have a high enough power factor to offset the thermal conductivity component. The FLO-TE is not limited by the thermoelectric figiire-of-merit ZT, and, thus, may attain efficiencies approaching the Caroot limit,.

{0029 The performance of FLO-TE devices may be understood though the effect of several dimensionless parameters on thermoelectric device performance. The first dimensional parameter is:

where p is density, v is velocity, c is heat capacity of the counter-flow fluid, £ is length of the TE stack, λ is thermal conductivity of the TE stack, m is the mass flow rate of the counter-flow fluid and k is the thermal conductance of a stack of TE modules. When β> 2 , there may be significant reduction of the phono conduction. When β> 2 , the coefficient, of performance η of the FLO-TE device is given by

where 3 _c and J _¾h are the heat flux density at the cold and hot ends of the device, J is the current density through the device element, T _c is the temperature at the cold end, ΔΤ is the temperature differential across the FLO-TE, σ is the electrical conductivity of the TE material, S is the Seebeek coefficient of the thermoelectric material, R is the electrical resistance of the stack of TE module, and 1 is the current through the stack of the TE module. As would be understood by a person of ordinary skill in the art with the benefit of the present disclosure, the FLO-TE materia! may include a substance that is selected on the basis of power factor and that has a high thermal conductivity, since the effects of the phonon conduction are mitigated when β> 2 . For example, ytterbium aluminate (YbA!. has a high power factor hut also a high thermal conductivity. When β>2 , the thermal conductivity of YbAL decreases in the FLO-TE, and, now YbAl.5 is quite suitable for use as a thermoelectric material because of its high ZT value when β> 2 .

Typical thin-film thermoelectric materials may include, but are not limited to, the materials listed in Table 1. Table 1

Exemplary FLO-TE materiais may include the materials in Table I , and, additionally, the high power factor materials such as, but not limited to, the materials listed in Table 2.

Table 2

[00301 For small currents (/→ 0 ), the COP /; --> - ?/ _c the Carnot COP, such that the COP ma vary as a function of current I. Current I may be expressed in terms of COP as f % ~ η ί S AT SAT

i J R ~ R [0031j An important dimensioiiless parameter Θ that defines the performance of FLO- I E heat pump is the ratio of thermoelectric (Peltier) cooling Q _c to the h at moved by the fluid <¾· which may be expressed as:

0 : Q _c SIT _C

Qi rhcAT βn < ' (4)

(00321 Θ can be modified (refined) to include the effect of imperfect coupling between the fluid and the stack of TE modules. A refined parameter Θ _χ can be expressed as;

Q _f e _f ffi c \T e _f fi where < is the effectiveness of the heat exchange between the stack of TE moduies and the fluid. Θ _χ may be of particular importance for refrigeration applicat ions. An exemplary set of d mensionless parameters values for operation at 40% of Camot COP of FLO-TE heat pump are as follows:

*7 ^0.4% β ^2.0 f - 1.5 ZT ₍ ··· 2 0^1.5 Θ _ν -2.0

[9033) The FLO-TE may also be configured for use in an. electric generator. In. power generation mode, the heat rejected per unit, area at the cold end of the TE, 7,.,. , is given by :

[0034) The heat absorbed per unit area at the hot end, J _h is given by:

J„, - ST + pvc AT

J i

As v -» 0 , J - ST. J +—AT + ~~~ and - ST J ι Λ7 ^' ^ '- · and., as v > .% . J ^■■■ ■ STJ

J ² i

and J _ak - S1].J

σ J f

AT _r

{0035| The efficiency ε ~——— --> —→—— as v -·> o and . «— - . The efficiency of a FLO-TE can approach Carnot efficiency and. the efficiency of tire FLO-TE is not dependent on ZT.

{0Q36J For imperfect heat transfer, the heat equation for the coupled system becomes,

where h the heat transfer coefficient per unit length, and X _f the thermal conductivity of the fluid. The temperature profile for the TE element may be expressed as:

rpvc

where cO is a constant and are coefficients dependent on the fluid transport properties.

16037) FIG. 6 shows a schematic of a thermoelectric apparatus 600 according to one embodiment of the present disclosure. The apparatus 660 may include a thermoelectric stack 610 of alternating thermoelements 630 and heat conducting layers 620. The thermoelements 630 may be bulk or thin film. In some embodiments, the heat conducting layers 620 may be optional. Each of the thermoelements 630 has a hot side and a cold side, and the thermoelements 630 are arranged in series along the thermoelectric stack 610, such that the therm.oelectric stack 610 is in thermal communication with a hot side thermal conductor 612 and a cold side thermal conductor 614. The hot and cold side heat conductors 612, 614, ma be comprised of any suitable good thermal conductor material, such as a metal or a ceramic. The hot side heat conductor 612 and the cold side heat conductor 614 ma include openings 616 and 618, respectively tha are configured to receive additional fluid .flow loops, including additional heat exchangers to move heat into and out of the counter-flow fluid,

{ ^" 0038} Each of the thermoelements 630 is configured to generate a temperature differential in response to received electrical energy. The thermoelements 630 include n-type thermoelements

632 and a p-type thermoelements 634.. winch may be paired and disposed on a metal layer 36. In some embodiments, there may be multiple pairs of thermoelements 630. In some embodiments, some of the pairs 632, 634 may be segmented, that is one pair may be composed of materials configured to operate in a first temperature range and another pair may be composed of materials to operate at a second temperature range. For example, a segmented thermoelectric stack may be configured to operate one series of pairs (at least one per layer) in a temperature range of 250-450 degrees Celsius and another series of pairs in a temperature range of 400-650 degrees Celsius

{ 039J The heat conducting layers 620 may be disposed between the thermoelement layers 630 and provide heat transfer between thermoelement layers 630 as well as to provide thermal coupling between the thermoelements and counter-flow fluid. The heat conducting layers 620 may be a thin metal sheet. A fluid loop 640 carrying a counter-flow fluid 650 that may flow along the thermoelectric stack 610 and be in thermal communication with the thermoelectric stack 610. The direction of the fluid flow is along the positive temperature gradient, that, is against (counter) to the direction of phonon (lattice) conductio in the thermoelectric stack, which is from the cold side 614 to the hot side 612, thus the fluid is referred to as the counter- flow fluid 650.

{0040} The thermal communication between the counter-flow fluid 650 and the thermoelements 630 may be enhanced by disposing optional fins 660 on the heat conducting layers 620. The fins 660 may extend into the counter-flow fluid 650. In some embodiments, th heat conducting layers 620 may extend into the counter-flow fluid 650. The counter-flow fluid 650 may be any suitable heat transfer fluid, including, but not limited to, one or more of; water, ethylene glycol-water mixtures, mineral oil, terphenyl, and a liquid metal. The counier-flow fluid 650 may absorb heat while traveling from the cold side to the hot side of the thermoelements 630. Some of the beat stored in the counter-flow fluid 630 may be transferred to the hot side of the thermoelement 630 or to the heat conducting layer 620/fin 660 associated with the thermoelement 630. The thermoelectric apparatus 600 may be implemented as a heat pump or as a power generator.

[0041 j FIG. 7 shows a schematic of another FLO-TE based apparatus 700 according to one embodiment of the present disclosure. The apparatus 700 has many of the same elements as apparatus 600 of FIG. 6; however, apparatus 700 includes a thermoelectric stack pair 71.0 that is configured so that the flow path is through the center of the mermoelements 720 of the thermoelectric stack pair 710. The thermoelectric stack pair 710 may include a plurality of thermoelements 720, where one side of the thermoelectric stack pair 71.0 is made up of n-type thermoelements 720» and the other side of the thermoelectric stack pai r 710 is made up of p-type thermoelements 720p. The thermoelements 720 may alternate with one or more constricted contacts 730 disposed between adjacent, layers of thermoelements 720. Both 720p and 720» elements are disposed on thermally conducting substrates which are stacked on one another. These substrates are in direct contact with the counter-flow fluid, which flows through the center of the thermoelectric stack 710, thereby achieving efficient thermal coupling between the counter-flow fluid 650 and thermoelements 72 n, 720p. (0042) FIG. 8 shows a three-dimensional perspective of another thermoelectric stack 800 for the apparattis 700, The thermoelencients 720 may be stacked with alternating constricted contacts 730 in the thermoelectric stack S00, The thermoelements 720 are shown as ring-type, however, this is exemplary and illustrative, as the thermoelements 720 may have other shapes, such as cubic, rectangular solids, ovoid, etc. The thermoelements 720 may be all tvtype or all p-type. if the thermoelectric stack 800 is n-type, then a complementing p-type theimoeiectric stack ma be paired with the thermoelectric stack 800 to enhance performance. As shown, the cylindrical shape of thermoelectric stack 800 allows counter-flow fluid to pass through and/or around the thermoelectric stack 800. The counter-flow fluid of thermoelectric stack 800 may circulate independently from the counter-flow fluid of a complementing thermoelectric stack,

j0043| FIG. 9A shows a. schematic of an air heater 900 according to one embodiment of the present disclosure. The air heater 900 may include a heat pump 91.0. The heat pump 910 may include a FLO-TE apparatus 700 (or an apparatus 600) that is thermal communication with a counter-flow fluid loop 920. The cold side of the apparatus 700 may be in thermal communication with a fluid loop 930 configured to move heat from the ambient into the apparatus 700. Hie fluid loop 930 may be in thermal communication with ambient air and receive heat from the ambient air. The hot side of the apparatus 700 may be in thermal communication with a fluid loop 940 that is configured to transport heat from the hot side of the FLO-TE apparatus into a compartment 950 or other volume to be heated. An optional heat exchanger 960 may be configured to transfer heat between the section of the counter-flow fluid loop 920 entering the cold side of the apparatus 700 and the fluid loop 930. Another optional heat exchanger 970 may be configured to transfer heat between section of the counter-flow fluid loop 920 lea vi ng the hot side of the apparatus 700 and the fl u id loop 940. |ft044| FIG. 9B shows a schematic of a water heater 980 according to one embodiment of the present disclosure. The water heater 980 may have substantially the same elements and configuration as the air heater 900; however, the water heater 980 may include a water tank .990, The fl uid loop 940 may be configured to pass through at least part of the water tank 990 in order to convey heat to the water contained therein. In one embodiment, the water tank is insulated such that leakage to ambient of the thermal energy deposited in the water is reduced,

[0045) FIG. 10 shows a schematic of a cooling system 1000 according to one embodiment of the present disclosure. As one of ordinary skill in the art would understand with the benefit of the present disclosure, cooling may be achieved by reversing the heat flow direction of a heating apparatus. The cooling system Ϊ0Θ0 ma include a heat pump 1010, which comprises a counter- flow fluid loop 1020 and a FLO-TE apparatus 700a. The first stage FLO-TE apparatus 700a ma be supplemented by additional FLO-TE apparatus 700b, 700c. The mimber of supplementing FLO-TE apparatuses 700b, 700c may be selected for the heat pump 1010 based on power and temperature requirements for the heat pump 1010 as well as the parameters B and θ _χ of the FLO-TE apparatuses 700b, 700c. The heat pump .1010 may be in thermal communication with a fluid 1050 to be cooled through a heat transfer loop 1030. The heat pump 1010 may also he in thermal communication with ambient air temperature through another heat transfer loop 1040. Heat may be pumped from the hot sides of the one or more apparatuses 700 to the heat transfer 1040 configured to transport heat away from the hot sides, while heat may be pumped into the cold sides of the one or more apparatuses 700 through from the fluid loop 30 configured to transport heat from the fluid 1050. The fluid. 1050 may be identical to suitable substances for the fluid 160. |ft046| The first stage apparatus 700a may cool the counterblow fluid due to the temperature differential across the apparatus 700a, which has hot side in thermal communication with ambient temperature. The cooled output of cold side of the apparatus 706a may be partially recirculated through the first stage apparatus 700a .from cold side to hot side and partially circulated though a cold side of the supplementing apparatus 700b. The., now colder counter- flow fluid enteriog the cold side of the apparatus 700b may be further cooled by apparatus 700b and again partially recirculated through the apparatus 700b and partially circulated to an additional supplementing apparatus 700c. The final supplementing apparatus 700c will circulated the remaining counter-flow fluid through the final supplementing apparaius 700c from cold side to hot side. The use of two supplementing apparatuses 700b, 700c is exemplary and illustrative only, as the loop configuration and number of supplementing apparatuses may be modified to accommodate desired efficiency, temperature differential, heat pumping, and cost parameters, A heat exchanger 1060 may be in thermal communication with the heat transfer loop 1030 and the counter- flow fluid loop 1020 to remove heat from the fluid 1050. Additional heat exchangers 1060a. 1060b. 1060c corresponding to recirculation loops from apparatuses 700a, 700b, 700c may be used to further extract heat from the fluid 1050. A heat exchanger 1 70 may be used to remove heat from the counter-flow fluid loop 1020 to ambient. Additional heat exchangers (not shown) in thermal communication with the heat transfer loop 1040 and corresponding to the apparatuses 700 may be used to increase the heat pumping to ambient, it must be noted that >1.0 for the cascade cooling so that each stage has enough cooling power to provide cold, fluid to the next stage and its own flow channel. The cascade design can have single-stage if the temperature differentials are small or multiple stages for large temperature differentials. |0047| FIG. 11 shows a schematic of a thermoelectric apparatus 1100 according to one embodiment of the present disclosure. The apparatus 1100 may include thermoelements 630 disposed between heat conducting layers 1110, 1120. The thermoelements 630 may be include alternating pairs of the n-type thermoelements 632 and the p-type thermoelements 634, where adjacent thermoelements 630 are connected by metal layers 636, The metal layers 636 provide thermal communication between one or mor of the thermoelements 630 and one of the heat conducting layers 1.1.10. 1 120. The metal layers 636 provide electrical communication between adjacent thermoelements 630 and between thermoelements on the ends of thermoelement sections 1 40 and one of the heat conducting layers 1110, 1120,

[0048] instead of being arranged in a thermoelectric stack 610 shown in FIG. 6, the thermoelements 630 and the metal layers 63 are disposed in a lateral thermoelectric stack between a hot terminal 1112 and a cold terminal 1114, parallel to the flow of the counter-flow fluid 650 ranni g through the fluid loop 640. The thermoelements 630 are disposed between the inner heat conducting layer 1110, which is adjacent to the conduit 1130 forming the fluid loop 640, and the outer heat conducting layer 1120. The thermoelements 630 may be organized into thermoelectric groups 1140, and each thermoelectric group 1140 is in contact with and fully overlapped by each of the heat conducting layers 1110, .1120; however, the inner heat conducting layers 1110 and the outer heat conducting layers 1120 are staggered relative to one another. Herein, "fully overlapping" means that the overlapped element does not extend beyond the outer bounds of the overlapping element in the direction of interest, such as along the conduit, and the fully overlapped element may or may not be coterminous with the overlapping element. This pattern of staggered heat conducting elements .11 0, 1120 and thermoelements 630 extends between the hot side terminal 1112 and the cold side terminal 1114, The hot and cold side terminals 1112, 1114 may be made of heat conducting materials, including, but not limited to, metal and ceramic, In some embodiments, the hot and cold side heat conductors 612, 614 may be used as hot and cold side terminals 1112, 1114, Each thermoelectric group 1140 is reversed from adjacent thermoelectric groups 1140 such that the connections of the thermoelements 630 by the metal layers 636 alternate between thermoelectric groups 1140, A person of ordinary skill in the art would understand that this alternating configuration of the thermoelectric groups 1140 maintains the heat and electric current flows in the same directions. The heat flow, shown by a path 1150, is from the hot side terminal 1112 to the cold side terminal 1114 through the heat conducting layers 1110, 1120 and across the thermoelements 630.

[0049] The inner heat conducting layers 1110 alternate with the insulation sections 1160, and the outer heat conducting layers alternates with gaps 1170, The insulation sections 1160 are electrically and thermally insulating., and the gaps 1170 also impede electrical and thermal communication. Thus, the path 1150 of the heat flow switches between the heat conducting layers 11 0, 1120 as the heat travels from the hot side terminal 1112 to the cold side terminal 1114. Some of the heat is removed to the counter-flow fluid 650 from the inner heat conducting layer 1110 though the fins 660. The conduit 1130 is electrically and thermal iy insulating, however, sections of the conduit 1130 provide heat conduction paths between the inner heat conducting layers 1110 and the fins 660, While the thermoelectric groups 1140 and heat conducting layers 1110, 11 0 are show on one side the fluid loop 640, in some embodiments, the thermoelectric groups 1140 and the conducting layers 1110, 1120 may be disposed on the outside surface of the conduit 1130 on multiple sides or surrounding the conduit 1 130,

[00501 12A shows a schematic of a thermoelectric apparatus 1200 according to one embodiment of the present disclosure. The apparatus 1200 may include n-type thermoelements 1232 and p~type ermoelements 1234 disposed on tlie outside of the conduit 1130. Th thermoelements 1232, 1234 are arranged in a stack between the hot terminal 1112 and the cold terminal 1114, The inner heat conducting layers 1110 are disposed between the respective thermoelements 1232, 1234 and the conduit 1130 along the lengt of a section the conduit 1130 between the hot terminal 1 2 and the cold terminal 1 4. Gaps 1270 betwee respective thermoelements 1232, 1234 are configured to provide electrical and heat insulation along the thermoelements 1232, 1234 and to direct the heat, flow path 1150 to alternate between the respective thermoelement 1232, 1234 and the inner heat conducting layers 1110. The thermoelements 1232, 1234 partially overlap with the inner heat conducting layers 1110 such that the heat flow path 1150 wil! alternate between the thermoelements 1232, 1234 and the inner heat conducting layers 1110 as the path 1150 travels from the hot terminal 1112 to the cold terminal 1114. The thermoelements 1232. 1234 are thin-film, and the lack of close pairing between n-type and p-type thermoelements enables manufacturing of devices that are smaller than paired bulk thermoelements

{0051 FIG. 12B shows a. close-up view of the inner heat conducting layer 11.1.0 and an n- type thermoelement 1232. The temperature between the heat conducting layers 1110 and the n- type thermoelement 1232 is substantially identical along the length of contact. Thus, a temperature differential AT along the n-type thermoelement 1232 occurs where the heat flow path shifts between the inner beat conducting layers 1.110 and the n-type thermoelement 1232, which is where the n-type thermoelement 1232 is not in contact with the inner heat conducting layer 1110, represented by the insulation section 1160. A complementing structure and process are used with p-type thermoelements 1234 and the inner heat conducting layers 1110. |ft052| FIG. 13A shows a schematic of a themioelectric apparatus 1300 according to one embodiment of the present disclosure. The apparatus 1300 may include the n-type and p-iype thermoelements 1232, 1234 and the inner and outer beat conducting layers 1110, 1120. Here, the respective ihemioeiements 1 32, 1 34 are folly overlapped by corresponding inner heat conducting layers 1110 and are partially overlapped by adjacent outer heat conducting layers 1120 to direct heat along the heat path 1150. An insulation section 1360 may be disposed between both the respective thermoelements 1232, 1234 and the inner heat conducting layers 1110. There is a partial overlap between the outer heat conducting layer 1120 and the paired thermoelemeTvi 1232, 1234 and inner heat conducting 1110 layers such that the heat flow path 1150 switches between the heat conducting layers 1110, 1 120 as the heat travels from the hot side terminal 1 112 to the cold side terminal 1114.

(0053} FIG. Ϊ3Β show a close-up view of part of the thermoelectric apparatus 1300. The temperature differential J T ls now formed across the respective thermoelements .1232, .1234 (n- type shown) on both sides of the insulation section 1360.

|0954} FIG. 14 shows a schematic of a thermoelectric apparatus 1400 according to one embodiment of the present disclosure. The apparatus 1400 is simila r in structure to the apparatus 1300; however, the insulation section 1160 is used, which is only isolates the inner heat conducting layers 1110. Also, thermoelements 1232, 1234 are fully overlapped by the outer heat conducting layers 1120. and the thermoelements 1232, 1234 partiall overlap adjacent inner heat conducting layers 1 1 10. Gaps 1 70 are large enough to be both between the adjacent outer heat conducting layers 1 1 0 and between the adjacent thermoelements 232, 1234. |ft055| FIG. 14B shows a close-up view of part of the thermoelectric apparatus 1460. The temperature differential T is formed across the respective thermoelement 1232, 1234 (n-type shown) on bot sides of the insulation section 1 J 60,

j 0056 FIG, 15 shows a schematic of a thermoelectric apparatus 1500 according to one embodiment of the present disclosure. The apparatus 1500 may include n-type thermoelements 1232, p-type thermoelements 1234, or both. The apparatus 1500 also includes the inner heat conducting layer 1110 and the outer conducting layer 1120 in the same arrangement as the apparatus 1300, that is. with each of the thermoelements 1232, 1234 being fully overlapped by one of the inner heat conducting layers I I 10 and partially overlapping with adjacent outer heat conducting layers 1120. It is also contemplated that aiternati ve embodiments of apparatus 1500 may use an arrangement consistent with the apparatuses 1200, 1400. A coonter-flow fluid 1550 is circulated through a conduit 1530, which is adjacent to the inner heat conducting layers 1110, and the insulation sections 1360. Conduit 1530 may have walls that are thermally conducting and electrically insulating. Exemplary materials for conduit 1530 may include one or more of i) ceramics such as, but not limited to, aluminum nitride (AIN) and ii) coated refractory metals, such as, but not limited to, molybdenum (Mo) or tungsten (W) coated with silicon nitride (SiN), aluminum nitride (AIN), or diamond-like carbon (DLC). The counter-flow fluid 1550 is a liquid metal, and the conduit 1530 is thermally conducting. Since the conduit 1530 is thermally conducting, the fins 66u are not necessary. Since the counter-flow fluid 1.550 is electrically conducting, the counter-flow fluid 1550 may form part of the electrical circuit with the n-type thermoelements 1 32, the p-type thermoelements 1234, or both. In an alternative embodiment, the conduit wall 1130 may be used with the fins 660 for heat conduction from the inner heat conducting layers 1110 to the counter-flow fluid 1550, |ft057| While the disclosure has been described with reference to exemplary embodiments,, it will be understood that various changes may be made and equivalents may be substituted, for elements thereof without departing from the scope of the disclosure. In addition, many modifications will be appreciated to adapt a particular instrument, situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that, the disclosure will include all embodiments fal ling within the scope of the appended ciaims.