WO1999004439A1

WO1999004439A1 - High efficiency thermoelectric converter and applications thereof

Info

Publication number: WO1999004439A1
Application number: PCT/CH1998/000290
Authority: WO
Inventors: Ivo F. Sbalzarini; Caspar O. H. Messner
Original assignee: Sbalzarini Ivo F; Messner Caspar O H
Priority date: 1997-07-15
Filing date: 1998-07-03
Publication date: 1999-01-28
Also published as: AU7904298A

Abstract

The invention relates to a device for cooling/heating an object using a heat-conducting converter element attached thereto. Said device can also be used to generate an electrical current by means of a thermoelectric generator.

Description

High efficiency transducer element and applications thereof

Element for power generation, heating and cooling

The present invention relates to a device for supplying or removing heat in or from a medium, such as a solid or a fluid. It comprises a thermo-electric current converter element with a highly heat-conducting dielectric and in or on the solid or in the fluid, i.e. a gas or a liquid, arranged heat conductor; a heat exchanger element, a cooling unit, a controllable heating / cooling with a thermostat, a heat store with an absorption and storage body of low thermal conductivity, all with a device according to the invention, and further uses of the devices according to the invention.

Starting position

As early as 1834, the French watchmaker Peltier discovered as a "counterpart" to the Seebeck effect, which had been known for 13 years at the time, that when direct current was passed through a thermocouple, heat was removed from the surroundings at one connection soldering point and transported to the other. In 1838, the German physicist demonstrated Lenz says that this newly discovered effect allows water to be frozen at a bismuth-antimony junction or that ice can be melted when the current flow is reversed, and attempts have been made to extract heat from one environment and supply it to another by means of so-called thermoelectric cooling .

Analogously, the reversal results in the so-called thermoelectric heating (not to be confused with the joule 'see resistance heating). When using such thermoelectric It is important for shear elements that on the one hand they are electrically insulated from the environment to be cooled or heated, but on the other hand that they are not too thermally insulated from the surroundings due to the electrical insulation.

Although known as a phenomenon, the Peltier effect could not be used for a long time due to the lack of good thermoelectric materials. Only the Seebeck effect for generating an electrical potential difference as a result of a temperature difference at the soldering points of a thermocouple was used in measuring devices (thermocouples for electronic temperature measurement), since the efficiency was irrelevant or could be compensated for by a higher sensitivity of the measuring electronics.

In line with the increasing need of ever broader sections of the population, in the mid-1950s and especially in the 1960s, a busy research and development activity in the field of thermoelectric cooling began.

After the corresponding semiconductor materials and semiconductor element combinations became known, it has become possible, for example, to operate cool boxes using the effects mentioned above.

For example, the Russian researchers Gebrüder Ioffe [57Iof] proposed to connect a Peltier element to the cooling fins in a refrigerator for better heat transfer via thin mica sheets, coated with a silicone coating and filled with aluminum powder. This is described, for example, in [6OG0I] on page 94 and following. The semiconductor combinations described and proposed by Ioffe and other researchers with significantly improved properties raised high expectations in practical use for household refrigerators, vacuum oil diffusion pumps, air and gas cooling, and large-scale systems for air conditioning, which, however, are different lack of economy of the elements.

Current state of the art

Investigations with Peltier elements showed that only a very small voltage of the order of 0.05-0.1 V with a high current of approx. 1-15 A leads to an optimal efficiency. However, this usually requires the electrical series connection of several elements and their mechanical combination to form a block in thermal parallel connection (usually 50 to 500 elements for larger outputs) in order to arrive at reasonably durable operating voltages and higher outputs (blocks with fewer elements, ie under 10, are also used in the area of low power and in measuring devices).

The heat absorbed on one side of such a block is transferred to the other side of the elements, where it then has to be dissipated, stored, for example by means of cooling fins or suitable cooling devices, or absorbed in the event of heat. The Joule 'see heat from the - as small as possible - electrical resistances of the element, the heat conduction through the material of the element in the opposite direction, the opposing Seebeck effect caused by the resulting temperature difference and heat conduction losses (proportional to the cable length) counteract this - limiting efficiency.

In every application, it is therefore important that an optimal heat transfer between the current-carrying solder joints of the element and the heat exchanger elements electrically insulated by them (heat source, heat sink) is guaranteed, which is not the case with the thermocouples used to date. Adequate electrical insulation with at the same time the best possible heat conduction is usually achieved using aluminum layers [GB 2 247 348, EP 0 592 044], particle-reinforced resins [GB 1 025 687], silicone gels [EP 0 592 044] or polymers Thin films (THERMAL CLAD ^* ) [US 5,040,381] achieved.

However, the increase in the thermal conductivity of these materials is associated with a weakening of the electrical resistance (Widemann / Franz / Lorenz rule) or they can only be sintered into solids with the addition of metallic binders. The effort was therefore primarily to reduce the thickness of such dielectric layers.

The state of the art is well presented in [95Row]. However, it only contains basic statements, "one should have a heat-conducting dielectric"; however, no specific materials or designs. It is the object of the present invention to fill this gap.

Development on a broad basis was discontinued at the end of the 1960s because with the classical materials (including the semiconductors) that obey the Widemann / Franz / Lorenz rule of proportionality of the electrical and thermal conductivity, the heat loss leads to the net cooling capacity. decreased significantly, which made the expected breakthrough in refrigeration impossible.

In practice, the efficiency of a Peltier element could not be increased by more than 14%, although theoretically (i.e. neglecting all losses due to insulation and thermal loss when transitioning to and from the element) up to 50-70% would have been possible. Since then, Peltier elements have only been used for instruments such as dew point measuring devices, for special mobile cooling devices, for space travel purposes, etc., where the lowest performance is required or the efficiency is irrelevant.

This is all the more unfortunate since the media used today in cooling units, such as ammonia, low molecular weight fluorocarbons (chlorine) hydrocarbons (especially frigens and freons), are no longer desirable for environmental reasons. It is therefore an object of the present invention to propose materials by means of which Peltier element combinations can be embedded in an electrically insulating manner, but which enable an optimal heat exchange with the heat exchanger elements on both sides and thus the environment.

The inventive solution

According to the invention, the problem is solved by means of a device according to the wording according to claim 1.

It is proposed that a thermoelectric current converter element, such as a Peltier element, is connected to (a) heat conductor (s) via at least one heat-conducting dielectric. A prerequisite for the operation according to the invention, for example a thermoelectric Peltier circuit, is the embedding of the solder joints, such as from Thermocouples of the optimal combination Bi2Te3 / Sb2Te3 50/50 with Bi2Te3 / Bi2Se3 75/25 (doped with copper bromide) together with their electrical connections (eg copper or silver connections) in a dielectric, which at the same time has good thermal conductivity (> 10 Wm ^ K ^"1 ) having.

Electrically insulating, ceramic-like materials according to the invention as well as composite materials or alloys thereof and polymers and / or polymer systems have been found to be suitable heat-conducting dielectrics; In particular, the so-called FGMs (Functional Gradient Materials) that have become available due to new procedural possibilities have been proven.

The conventional dielectrics hinder the flow of heat, while the new materials proposed according to the invention conduct the heat optimally, but not the electrical current, so that a good heat-current flow design is possible even with relatively small temperature differences.

It is proposed according to the invention that the heat-conducting dielectric contains at least one of the following substances: aluminum nitride, boron nitride, carbon, silicon carbide, beryllium oxide, silicon oxynitride, aluminum oxynitride, silicon-aluminum nitride and / or composite materials or alloys thereof and / or diamond-structure ceramic and / or Diamond and / or carbon fiber composite materials and / or polymers and / or polymer systems (ideally with low water absorption capacity), in particular polytetrafluoroethylene (PTFE, Teflon), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyamideimide (PAI) and / or fiber-offset / Reinforced polymers and / or filled plastics with directional thermal conductivity and / or functional gradient materials (material, which has gradually changing properties over a certain distance) according to Claim 8. For example, pure beryllium oxide has a thermal conductivity coefficient of> 250 Wm ^ K ^"1 , silicon carbide has such a coefficient between 190 and 240 Wm ^ K ^'1 , and aluminum nitride also has a thermal conductivity coefficient from about 180 to 220 m ^ K ^"1 on. These materials have been developed especially as cutting materials, lubricants, crucible materials, heat traps and additives and are still in constant development with regard to thermal conductivity and are currently not fully optimized. For this reason, the thermal conductivity values mentioned above are only approximate.

According to the invention, it is further proposed that the converter element, as already mentioned, is a Peltier element, a thermoelectric generator based on the Seebeck principle or a Joule 's resistance element, which consists of at least one heat conductor or a heat transport layer via the heat-conducting dielectric a highly thermally conductive material. The heat conductor or the heat transport layer can be made from a highly thermally conductive metal, such as copper, aluminum, silver or gold, or from the same material as the thermally conductive dielectric, ideally from a functional gradient material FGM with the outside in favor ever better thermal conductivity, steadily increasing electrical conductivity.

Highly heat-conducting plastics and / or the composite of carbon fibers and / or certain ceramics and diamond in the corresponding crystallographic directions (λ> 1250 Wm ^ K ^"1 ) have also proven to be suitable as a heat-conducting layer.

The individual elements are combined into blocks (see FIG. 1) as described above. Between the solder joints and the respective heat exchanger element is a thin layer of the thermally conductive dielectric. Assuming that the elements are made of Bi2Te3 semiconductors (a classic material with a high level of effectiveness), HJ Goldsmid calculates that at an average ambient temperature of 300 K and a temperature difference of 30 K above the element, an optimal operating voltage of 0.045 V per Solder joint. With an ohmic resistance of 0.05 Ω, this corresponds to a current of 0.9 A. In order to arrive at reasonable voltage and power values (approx. 12 V operating voltage), around 270 elements would have to be connected in series (one block ). The individual elements can be kept as small as possible (and sensible in terms of electrical resistance). Under these conditions, a maximum efficiency of approx. 66% would be achievable according to Goldsmid models.

Previous dielectrics, however, reduce it due to their low thermal conductivity from only about 1-5 m ^ K ^"1 to less than 25%. In the case of a dielectric according to the invention with a thermal conductivity of about 200 Wm ^ K ^{" 1} , this additionally reduces - to maintain the Heat flow through the block - the internal temperature difference to be obtained from the element (i.e. between the solder joints within the insulation) is well below 1 K. The total efficiency therefore approaches the theoretical maximum value and should be around 64%, which leads to considerably higher cooling capacities than with conventional designs.

According to the invention, it is further proposed to layer a plurality of blocks of thermocouples between the two final heat transport layers on top of one another. The cascade elements achieved in this way (see FIG. 3) are more efficient at higher temperature differences than tiered blocks. The improvement in efficiency is greater the closer the temperature difference generated by the element is to the maximum achievable temperature difference. For example, if the temperature difference during operation is 75% of the maximum, the efficiency of a two-stage cascade is about 1.5 times that of a one-stage block in the same environment. If the temperature difference is 95% of the maximum value, the cascade efficiency is about 5 times as high as that of the corresponding single-stage block. The maximum achievable temperature difference can theoretically be doubled with a cascade of two levels.

In practice, however, a maximum increase of a factor of 1.5 was attainable. Not least because electrical insulation is also required between two stages, which additionally limited the heat flow due to the poor thermal conductivity of conventional dielectrics. Equipping such cascade elements with heat-conducting dielectrics according to the invention increases the maximum temperature difference and thus also the efficiency. It is therefore advisable to use cascade elements to increase the temperature difference that can be achieved, although these are not limited to three levels. Due to the improved heat flow through the insulation layers, cascades of four or more levels are also sensible.

The configuration according to the invention, for example a Peltier element, makes it economical in competition with the well-known Linde refrigeration machine, since the heat losses become small and the theoretical efficiency of the element can be achieved up to a few percent. So that is the Peltier element is a sensible further development compared to classic chillers.

The devices defined according to the invention are particularly suitable for the configuration of heat exchanger elements for heating or cooling a solid, a liquid or a gas. The heat conductor or directly the dielectric is connected in a heat-conducting manner to the material to be heated or cooled, and the converter element is designed to be operable and connected to the heat conductor in such a way that heat is supplied to or withdrawn from the material when an electrical direct current is applied to the converter element.

Another use of the device according to the invention is in the controllable cooling or heating with a thermostat, the converter element being operable in both directions by switching over to cooling or heating by reversing the current flow through the element (polarity reversal). The thermal output can also be adapted to the respective requirements by regulating the current.

Another use lies in the operation of a heat store with an absorption and storage body of low thermal conductivity and with heat-conducting layers that extend flat in the body, as is known, for example, from European Patent No. 306 508. In this patent, an absorption or Storage body with a heat-conducting layer extending therein, wherein heat is supplied to or removed from the storage body via a Peltier element. Since the present invention is suitable for use in a heat store according to the mentioned EP 306 508, all of them are hereby in the European one mentioned Variants of such an absorption and storage body using a device according to the invention are also to be considered as included in this patent specification.

However, the device according to the invention can also

- for condensing cooling of vacuum oil diffusion pumps,

- for cooling or heating switchable thermostats,

- for cooling dew point measuring devices,

- for the use of waste heat from long-running incandescent lamps,

- for battery charging or radio supply,

for energy supply to remote objects (as a thermoelectric generator according to FIG. 3),

- for waste heat from heating systems,

- for cooling thermally conductive carbon fiber reinforcements of plastics,

- in combinations of cooling units in the kitchen with heating in living rooms,

- for medical-technical cooling / heating or power generation purposes,

for cooling electrical components such as microprocessors etc. (ideally in conjunction with a flat heat transport layer integrated directly in the chip, as is known for example from EP 306 508), in multi-stage cascades for cooling superconductors and / or thin-layer high-temperature superconductors to fall below the limit temperature required for superconductivity and thus prevent further heat development,

- for cooling, heating and / or tempering beverages and / or other liquids as a storage area, hollow cylinder, closed cabinet or handy whisk,

- for cooling / heating of concrete elements via heat-conducting bandages for renovation, freezing, drying and / or other processing purposes,

- for freezing the ground (via cooling pipes or supercooled brine) in civil engineering,

- for air conditioning,

- for the liquefaction of gases,

- etc.

be used.

Also proposed is a method for cooling composite materials reinforced with heat-conducting polymer fibers, such as carbon fibers in particular, wherein the heat in the composite material by means of the fibers used for the reinforcement via a heat-conducting dielectric and at least one Peltier element connected thereto (by passing a current through the Peltier element) is withdrawn. When using carbon fiber-reinforced plastic composites, especially in high-tech applications, such as in aircraft technology, it has been shown that heat dissipation is a critical factor, particularly in the case of parts subject to high stress, since, as is well known, classic plastics are poor heat conductors. The attachment of conventional (classic) cooling units in such composite materials is practically impossible, so that the device proposed according to the invention now offers a suitable solution. The carbon fibers or carbon fabrics used for reinforcement in these composite materials can, as suggested above, be connected to a Peltier element via a heat-conducting dielectric (or possibly also directly).

When such composite material parts are subjected to mechanical stress, heat is generally generated, which has a negative effect on the interface connection between the carbon fibers and the plastic matrix. If the heat can only be dissipated insufficiently, the dynamic strength decreases until finally there is a detachment at the interface between the carbon fibers and the plastic matrix. As a result, fatigue phenomena such as cracks or even breaks occur on the composite part after a certain time.

It is precisely through the use of a Peltier element that it is now possible to prevent this undesirable heat build-up by using the current conducted through the Peltier element to dissipate the heat generated from the carbon fibers.

Corresponding investigations were already carried out by NASA and Boeing in the 1970s. They showed that the use of Peltier elements for these cooling purposes would be ideal, but is not feasible in aircraft construction due to the excessive weight load. With a Peltier element designed in accordance with the invention, a much higher degree of efficiency and thus an essential one can be achieved reduced weight can be achieved with the same required performance, which makes this technology interesting again.

Explanation of the devices according to the invention

The invention is with reference to the figures and the embodiment variants shown therein, respectively. graphic representations explained.

Show:

1 shows a Peltier element designed according to the invention (schematically),

2 shows a Peltier element using functional gradient materials,

3a shows an example of a three-stage cascade thermocouple according to the invention,

3b shows an example of a two-stage cascade thermocouple according to the invention,

4 shows a thermal generator designed according to the invention (schematically),

5 shows a transducer element, such as a Peltier element, with a heat-conducting layer arranged on one side and directed in a directional manner,

6 shows a heat store with a Peltier element, analogous to a heat store according to EP 306 508,

Fig. 7 shows the dependence of the efficiency of a Peltier element on the thermal conductivity of the Dielectric layers and the cooling power provided by the element and

8 shows the dependence of the efficiency of a Peltier element on the thermal conductivity of the dielectric layers and the temperature difference prevailing over the element.

1 shows a thennoelectric converter element designed according to the invention, the individual semiconductor thermocouples 1, electrically connected in series and thermally in parallel, being combined in three dimensions to form a block. The electrical connection between the individual semiconductor pieces is established via flat metallic conductor connections 3, the outermost conductor pieces at the beginning and at the end of the series circuit chain being provided with electrical connections 7 for supplying current. The block is closed to the outside in a heat-conducting but electrically insulating manner by layers of the heat-conducting dielectric 5 which are as thin as possible and heat conductors 9 of large surface area (for example cooling plates, cooling fins or heat exchangers) attached to both sides. Bolts with the lowest possible thermal conductivity (not shown) stretched between the final heat conductors 9 (not shown) can be used to mechanically stabilize the block in very large assemblies. The direction of the heat flow in the direction of the arrow is determined by the polarity of the voltage applied to the block, and its magnitude by the current intensity passed through the block.

FIG. 2 shows a thermoelectric converter element according to FIG. 1, but without a separate thermally conductive dielectric. Rather, the dielectric and the final heat-conducting plates form a unitary block 11 from the same functional len gradient material FGM (material which has gradually changing properties over a certain distance). The diagrams qualitatively record the change in the thermal and electrical conductivities within the material over the entire distance.

It can be seen that the electrical conductivity is close to zero in the vicinity of the element, that is to say the material acts as a dielectric, the thermal conductivity still being relatively good. With increasing distance from the element, the electrical conductivity increases sharply, in favor of an also increasing thermal conductivity. The heat transfer to the outside thus becomes better and better with increasing metal character of the material, which contributes to an increased heat flow through the element (minimization of boundary layers).

3a shows a pyramid-shaped three-stage cascade of thermocouples. The individual blocks 13, constructed analogously to FIG. 1, are one above the other, separated by plates made of heat-conducting dielectric 5a. The flat metallic conductor connections 3 known from FIG. 1 are pulled through the dielectric layers and supply all stages with current. On the top and bottom of the cascade there are in turn closing layers of the heat-conducting dielectric 5. The heat transport layers or cooling plates comprising the block are not shown here. The way the cascade works is based on the end temperatures that change with each stage. The bottom stage cools the warm end of the middle one, which lowers the temperature further towards its cold end and the top stage lowers it again. The total temperature difference on the cascade can therefore be much higher than for a single-stage block. The pyramid shape It makes sense, since the required power increases downwards (electrical loss heat generated in the element and heat radiated in from the outside must be removed from each stage) and a concentration on smaller areas with decreasing temperature may be desirable.

3b shows a two-stage thermocouple cascade analogous to FIG. 3a, the entire element being larger here and both stages being the same size. The separating layer 5a in turn consists of the thermally conductive dielectric.

4 shows an example of a thermoelectric generator using the Seebeck effect. In the chimney 15 of a burner (or other heat source) 17 metallic fins or plates 19 are attached. These are connected via the thermally conductive dielectric 5 to a thermoelectric converter element 21 (analogous to FIG. 1) which is arranged around the chimney 15. On the outside of the transducer element 21, large-area cooling plates or cooling fins 23 are attached via the heat-conducting dielectric 5. Electrical connections 7 are provided at both ends of the thermocouple series.

The inner fins 19 are heated by the hot exhaust gases of the burner 17 escaping in the direction of the arrow and form the warm side of the thermocouples 21. Outside, the cooling fins 23 are cooled by the ambient air (or by cooling water) and form the cold side. Due to the temperature difference at the converter element 21, an electrical voltage arises at the end connections 7; the generator produces electricity.

FIG. 5 shows a thermoelectric converter element constructed analogously to FIG. 1, which on one side is provided with a heat conductor plate (cooling plate) 9, which is connected to the semiconductor thermocouples 1 via the heat-conducting dielectric 5. On the other hand, the heat-conducting dielectric 5 is connected directly to a flat layer of a heat conductor 25 with conductivity directed in the direction of the arrow.

6 shows a solid-state heat accumulator 33 (according to EP 306 508) of low thermal conductivity with a heat transport layer 31 of high thermal conductivity arranged flatly therein. A thermoelectric converter element 29 is connected to it via a heat-conducting dielectric and is fed by a direct current source 27 via the electrical connections 7.

Depending on the polarity of the direct voltage, heat is supplied to the storage 33 via the converter element 29 and the heat transport layer 31 (charging the storage) or withdrawn (discharging the storage) or the difference between the storage temperature and the outside temperature can be used on the element 29 to generate electricity.

FIG. 7 illustrates the dependency of the efficiency (COP) of a Peltier element on the thermal conductivity of the final dielectric layers and the cooling output provided. An example element with the following numerical values was used: The side length of the dielectric plates is 40 times as large as their thickness, the thermoelectric elements consist of Bi2Te3 semiconductors, the mean ambient temperature is 300K and the temperature difference generated by the element outside is 30K. In general, however, the same qualitative relationships also result from other numerical values. One can clearly see that the efficiency increases strongly with increasing thermal conductivity of the dielectric, but decreases slightly with increasing cooling capacity. In addition From it can be seen that the maximum achievable at a certain efficiency also increases significantly with the thermal conductivity of the dielectric. The underlying mathematical results are explained in more detail in the following section.

8 illustrates the dependency of the efficiency (COP) of a Peltier element on the thermal conductivity of the final dielectric layers and the temperature difference generated by the element. An example element with the following numerical values was used as a basis: The side length of the dielectric plates is 40 times as large as their thickness, the thermoelectric elements consist of Bi2Te3 semiconductors, the average ambient temperature is 300K and the cooling power provided by the element is 100 watts. In general, however, the same qualitative relationships also result from other numerical values. It can be seen that the efficiency increases with increasing thermal conductivity of the dielectric, and the greater the smaller the temperature difference across the element. At the same time, however, the temperature difference that can still be achieved with a certain degree of efficiency also increases with increasing thermal conductivity of the dielectric. The underlying mathematical results are explained in more detail in the following section.

Theoretical calculations

The basic calculations are based on the following formulas and procedures:

Maximum thermoelectric efficiency (after [60Gol]):

Overall efficiency of a thermocouple cascade

^π , _v + - 2)) - 2 [2]

Optimal operating voltage per element (solder joint)

Maximum achievable temperature difference

Δ ^ _a = 27 \, "[4]

JI + Z-Γ _W + ι

Temperature difference to be held internally by the element

Δx Δx

AT _m = AT _eff + P _» → P _k - [5]

^Λ Λ> «/. ^'Λ l) ιd. ^"Λ

Maximum efficiency with dielectric:

Efficiency with ideal thermoelectric material

7 ^~ , -Δ772

[7] AT

thermal power:

[8th]

Meaning of the symbols:

Average ambient temperature

ΔT temperature difference across the element

"Coefficient of performance" of the thermoelectric material (material constant)

αpn Differential Seebeck coefficient of two materials

ΔT "Effective temperature difference on the outside of the element

ΔT, temperature difference to be held internally by the element

ΔT _m Maximum achievable temperature difference P "Thermal output given off on the warm side

P _k Thermal power absorbed on the cold side

P _el Electrical power consumption of the element

Δx thickness of the dielectric layer

λ _Diel thermal conductivity of the dielectric

A base area of a dielectric layer

N Number of stages in a thermocouple cascade

η Efficiency of a single-stage element over the full temperature difference

η _maχth Maximum theoretical efficiency

η _max Maximum efficiency with dielectric

η _N Max. total efficiency of an N-stage cascade

(IR) _opc Optimal operating voltage U = RI per solder joint

In order to calculate the maximum efficiency [6], in addition to the ambient temperature and the material data, the temperature difference [5] to be held internally by the element is decisive. This, in turn, depends on the data of the dielectric and the thermal performance provided by the element, whereby an optimal dielectric becomes more and more important with increasing performance. The efficiency calculated in this way applies to operation with optimal voltage [3] and is always below the theoretical maximum [1], which in turn is limited by the maximum efficiency of an ideal thermodynamic machine [7]. The maximum temperature difference [4] that can be achieved with an element is only dependent on the ambient temperature and the Material data. It forms the upper limit for ΔT and the efficiency drops to zero when it is reached. With a cascade of N stages, the total theoretical efficiency (without dielectric losses) increases according to [2] and thus also the maximum achievable temperature difference.

ATTACHMENT

Bibliography :

[57Iof] A.F. IOFFE, Semiconductor Thermocouples and

Thermoelectric Cooling, Infosearch, London, 1957

[60Gol] H.J. GOLDSMID, Applications of Thermoelectrici ty, Methuen & Co. Ltd., London, 1960

[95Row] D.M. ROWE (Editor), CRC Handbook of THERMOELECTRICS, CRC Press, Boca Raton / New York / London / Tokyo, 1995

Claims

claims

1. Device for supplying or removing heat in or from a solid or fluid, comprising a thermoelectric current transducer element and arranged in or on the solid or in the fluid, such as in particular a gas or a liquid, characterized in that a heat-conducting dielectric is provided as the heat conductor, which is connected to the transducer element and / or that the transducer element is connected to the heat conductor (s) at least on one side via a heat-conducting dielectric, the dielectric having a thermal conductivity of λ> 10 Wm ^ K ^{" 1} has.

2. Device, in particular according to claim 1, characterized in that the thermally conductive dielectric is a thermally conductive, largely electrically insulating material or composite material with λ> 10 Wm ^ K ^"1 .

3. Device, in particular according to one of claims 1 and / or 2, characterized in that the heat-conducting dielectric has a specific electrical resistance> 10 Ωcm ^"1 , preferably> 10 ⁶ Ωcm ^{" 1} , even more preferred

> 10 ¹² Ωcm ^"1 .

4. The device, in particular according to one of claims 1 to 3, characterized in that the heat-conducting dielectric has a thermal conductivity of λ> 30 Wm ^ K ^"1 , preferably λ> 50 Wm ^ K ^{" 1} , even more preferably λ> 100 Wm ^ K ^"1 has.

5. The device, in particular according to one of claims 1 to 4, characterized in that the thermally conductive dielectric - A thermally conductive, largely electrically insulating ceramic or ceramic-like material

- A ceramic composite or a ceramic alloy

- a carbon fiber composite

- A polymer, polymer system and / or a fiber-offset polymer

- a filled plastic with high thermal conductivity

is.

6. The device, in particular according to one of claims 1 to 5, characterized in that the heat-conducting dielectric comprises at least one of the following substances:

- aluminum nitride,

- boron nitride,

- silicon carbide,

- carbon and / or alloys thereof,

- beryllium oxide,

- silicon oxynitride,

- aluminum oxynitride,

- Silicon-aluminum nitrides and / or

- Ceramic with a diamond-like structure and / or

- diamond and / or - composite materials or alloys thereof,

- carbon fibers and / or composite materials thereof,

- Wood or lignin and / or composite materials thereof

- Polymers and / or polymer systems, ideally with less

Water absorption capacity, in particular

- polytetrafluoroethylene PTFE Teflon,

- polyphenylene oxide PPO,

- polyphenylene sulfide PPS,

- polyamideimide PAI and / or

- fiber-offset / reinforced materials such as ceramics, polymers,

Glasses, metallic glasses, metals, etc.,

- filled plastics with directed thermal conductivity

and or

- Functional gradient materials with the outside

gradually increasing thermal conductivity

7. The device, in particular according to one of claims 1 to 6, characterized in that the heat-conducting dielectric comprises in particular silicon / aluminum / oxygen / nitrogen compounds.

8. The device, in particular according to one of claims 1 to 7, characterized in that the thermoelectric current converter element is a Peltier element, a thermogenerator using the Seebeck effect or a Joule's resistance. is element, which is connected via the heat-conducting dielectric to at least one heat conductor or a heat transport layer made of a highly heat-conducting material.

9. The device, in particular according to one of claims 1 to 8, characterized in that the heat conductor is made at least on one side from the same material as the heat-conducting dielectric.

10. The device, in particular according to one of claims 1 to 8, characterized in that the heat conductor and the heat-conducting dielectric are made at least on one side from the same functional gradient material (FGM), which gradually increases its dielectric character with increasing distance from the element in favor of one steadily increasing thermal conductivity loses.

11. The device, in particular according to one of claims 1 to 8, characterized in that the heat-conducting layer or the heat conductor made of a highly thermally conductive metal, such as in particular copper, aluminum, silver, gold and the like and / or a highly thermally conductive plastic and / or a carbon fiber Composite and / or diamond-like ceramic or diamond.

12. The device, in particular according to one of claims 1 to 8, characterized in that the thermocouples (semiconductor elements), the dielectric and the final

Heat conductors are made of the same functional gradient material (FGM), which gradually changes its properties from the semiconductor character through the dielectric character to the metal character, so that no boundary layers occur anymore.

13. The device, in particular according to one of claims 1 to 12, characterized in that the thermocouples between the final heat-conducting layers are arranged in blocks in a cascade-like manner in a plurality of mutually electrically insulated layers, and the electrical insulation between the stages from the heat-conducting dielectric, as in characterized one of claims 1 to 7, are manufactured.

14. The device, in particular according to one of claims 1 to 12, characterized in that the thermocouples are arranged in several layers one above the other and are electrically insulating and thermally conductive via at least the thermally conductive dielectric, as characterized in one of claims 1 to 7, with the final thermally conductive layers are connected.

15. A device for heating and / or cooling a solid, a liquid or a gas, comprising at least one device, in particular according to one of claims • 1 to 14, characterized in that the heat conductor or the heat-conducting dielectric directly with the heat to be heated or material to be cooled is connected and that the transducer element is designed to be operable or is connected to the heat conductor in such a way that heat is supplied to or withdrawn from the material when an electrical current is applied to the transducer element.

16. Cooling / heating unit with at least one device, in particular according to one of claims 1 to 14, characterized in that the converter element extracts or supplies heat to its surroundings when current is passed and that the heat conductor or the heat transport layer is designed as a cooling element, such as a room air cooling element, a refrigerator cooling element, cooling fins and / or the like or heat tends to be connected to such a cooling element and / or a heat-dissipating liquid.

17. Controllable cooling / heating with a thermostat and at least one device, in particular according to one of claims 1 to 14, characterized in that the converter element can be operated in both directions, the switchover to cooling or to heating in each case by reversing the current flow. Direction takes place through the converter element (polarity reversal) and / or the thermal power can be adapted to the respective situation by regulating the current.

18. Heat storage device with an absorption and storage body of low thermal conductivity and with heat conduction or surface area extending in the body on one or more levels. Heat transport layers, consisting of a material with a high coefficient of thermal conductivity, and with at least one associated device, in particular according to one of claims 1 to 14, for feeding or. Extract heat in the resp. from the storage body and / or for electrical energy generation by means of the temperature difference between storage and environment.

19. Device for cooling composite materials reinforced with thermally conductive polymer fibers and / or carbon fibers, characterized in that the fibers used in the composite material for reinforcement via the thermally conductive dielectric or directly with the soldering points of a Peltier element, in particular according to one of claims 1 to 14, are connected.

20. Device for cooling and / or heating electrotechnical and / or electronic and microelectronic components, assemblies and / or housings or rooms by means of at least At least one device, in particular according to one of claims 1 to 14, characterized in that the thermoelectric current converter element is attached via the heat-conducting dielectric or directly to the housing or boundary area of the component / volume to be cooled / heated and otherwise via the heat-conducting dielectric is connected to a heat conductor for heat dissipation / absorption, such as a cooling plate, a liquid heat exchanger or the like.

21. Device for cooling and / or heating electrotechnical and / or electronic and microelectronic components, such as in particular microprocessors, by means of at least one device, in particular according to one of claims 1 to 14, characterized in that the thermoelectric current converter element directly or via the Thermally conductive dielectric is integrated in the component or forms part of the same.

22. Device for cooling electrotechnical and / or electronic and microelectronic components, such as in particular microprocessors, by means of at least one device, in particular according to one of claims 1 to 14, characterized in that the thermoelectric current converter element via the thermally conductive dielectric or directly with a Flat heat conductor integrated directly in the component or chip is connected.

23. Device for cooling thin-layer high-temperature superconductors and / or components made from appropriate materials by means of at least one pellet element connected directly or via the heat-conducting dielectric to the superconductor, in particular according to one of claims 1 to 14, characterized in that the Peltier element made of multi-stage gene cascades, preferably according to one of claims 13 or 14.

24. Device for cooling superconductors and / or assemblies made therefrom by means of at least one Peltier element connected directly or via the heat-conducting dielectric to the superconductor, in particular according to one of claims 1 to 14, characterized in that the Peltier element consists of multi-stage cascades , preferably according to one of claims 13 or 14.

25.Device for cooling / heating concrete piles and / or concrete elements for concrete renovation, freezing, drying and / or other processing by means of carbon fiber mats wrapped around the concrete element and / or other suitable heat-conducting bandages or coverings and at least one thermoelectric converter element connected thereto, in particular according to one of claims 1 to 14.

26. Device for cooling / heating beverages and / or other liquids, characterized in that at least one thermoelectric element, in particular according to one of claims 1 to 14, is attached in the head of a rod-shaped “whorl” made of heat-conducting material and via the heat-conducting Dielectric is connected to the elongated heat conductor, with the power supply being able to be carried out using batteries or a power supply unit.

27. Device for freezing the surrounding earth and / or underground and surface water in civil engineering, characterized in that flat heat conductors attached to and / or in the material to be cooled are connected with at least one heat exchanger via the heat-conducting dielectric or directly with it. bound, thermoelectric current converter element, in particular according to one of claims 1 to 14, are connected.

28. A method for cooling composite materials reinforced with heat-conducting polymer fibers and / or carbon fibers, characterized in that the heat via the fibers used for the reinforcement and at least one Peltier element connected directly or via the heat-conducting dielectric, in particular according to one of claims 1 to 14, through which a current is conducted, is withdrawn.

29. Device for, for example, local cooling / heating of tissue in medical technology by means of at least one thermoelectric current converter element, in particular according to one of claims 1 to 14, characterized in that the final heat conductor and / or the thermally conductive dielectric of the converter element as a contact surface trained and / or directly thermally conductive in medical devices such as Needles, electrodes, blades, electric blankets, bandages, pens etc. are integrated or used to temper them.

30. Device for the transport and / or storage of perishable foods or other goods in need of cooling by means of at least one thermoelectric transducer element, in particular according to one of claims 1 to 14, characterized in that the thermoelectric element is integrated directly or via the thermally conductive dielectric in the transport container.

31. A method for cooling and / or heating a solid and / or a fluid, such as, in particular, a liquid or a gas, by means of at least one thermoelectric current converter element connected thereto in a heat-conducting manner, indicates that the solid or the fluid, such as in particular the liquid or the gas, is withdrawn or supplied with heat by passing a current through the transducer element via a thermally conductive dielectric, the dielectric having a thermal conductivity of λ> 10 Wm ^ K ^"1 .

32. Method for generating electric current by means of a natural temperature difference applied to at least one thermoelectric current converter element and / or caused by artificial heating on at least one side, the converter element using a thermally conductive dielectric with a thermal conductivity of λ> 10 Wm ^ K ^{" 1 is} electrically isolated from its surroundings.

33. The method, in particular according to claim 31, for cooling / heating beverages and / or other liquids, comprising a thermoelectric current converter element, in particular according to one of claims 1 to 14, characterized in that the liquid to be cooled / heated (in one Vessel)

- directly on the thermally conductive end plate of at least one horizontally attached or mounted in a table thermoelectric element,

- In a thermally conductive, connected or provided with at least one thermoelectric element hollow cylinder or

- In a closed cabinet provided with at least one thermoelectric element

is provided.

34. The method, in particular according to claim 31, comprising a device, in particular according to one of claims 1 to 14, characterized in that the thermocouple for tempering a liquid is provided in any arrangement with a controllable thermostat.

35. The method, in particular according to claim 31, for cooling thin-layer high-temperature superconductors and / or components made from corresponding materials by means of at least one Peltier element connected directly or via the heat-conducting dielectric to the superconductor, in particular according to one of claims 1 to 14, characterized in that the temperature in the thin-layer cooling area can be reduced below the limit temperature required for superconductivity by multi-stage cascades, preferably according to one of claims 13 or 14.

36. The method, in particular according to claim 31, for cooling superconductors and / or assemblies made therefrom by means of at least one Peltier element connected directly or via the heat-conducting dielectric to the superconductor, in particular according to one of claims 1 to 14, characterized in that multistage cascades, preferably according to one of claims 13 or 14, the temperature in the entire superconductor can be reduced below the limit temperature required for superconductivity.

37. The method, in particular according to claim 31, for cooling / heating concrete piles and / or concrete elements for concrete renovation, freezing, drying and / or other processing by means of carbon fiber mats wrapped around the concrete element and or other heat-conducting bandages and at least one thermoelectric transducer element connected thereto, in particular according to one of claims 1 to 14, through which an electrical current is passed, for supplying and removing heat.

38. The method, in particular according to claim 31, for maintaining a constant temperature in a solid, a liquid or a gas for a long time by means of at least one thermally electrically connected thermoelectric converter element, in particular according to one of claims 1 to 14, characterized in that the temperature is controlled by means of thermostat-controlled regulation of the current conducted through the element.

39. The method, in particular according to claim 31, for increasing the stability by freezing the surrounding soil and / or underground and surface water in civil engineering, characterized in that the heat via flat heat conductors attached to and / or in the material to be cooled and at least one , is withdrawn via the heat-conducting dielectric or directly connected thermoelectric current converter element, in particular according to one of claims 1 to 14.

40. The method, in particular according to claim 31, to increase the stability by freezing the surrounding soil and / or underground and surface water in civil engineering, characterized in that brine is supercooled by means of a thermoelectric current converter element, in particular according to one of claims 1 to 14 and is pumped into cooling pipes or directly into the area to be cooled.

41. The method, in particular according to claim 31, for cooling electrotechnical and / or electronic and microelectronic components and / or assemblies and / or housings by means of at least one thermoelectric transducer element connected via the heat-conducting dielectric or directly connected thereto, in particular according to one of claims 1 to 14 , characterized by net that the waste heat of the electrical system to be cooled is dissipated by passing a current through the converter element.

42. The method, in particular according to claim 31, for reducing the sensitivity to pain by, for example, local hypothermia of the tissue by means of at least one thermoelectric transducer element, in particular according to one of claims 1 to 14, characterized in that the final heat conductor or directly the heat-conducting dielectric of the cold Side is brought into contact with the tissue.

43. The method, in particular according to claim 31, for the medical and / or healing heating of tissue by means of at least one thermoelectric transducer element, in particular according to one of claims 1 to 14, characterized in that the final heat conductor or the heat-conducting dielectric directly in contact with the warm side brought with the tissue.

44. The method, in particular according to claim 31, for decentralized cooling / heating of drinking water and / or production of ice water by means of at least one thermoelectric current converter element, in particular according to one of claims 1 to 14, characterized in that the water at the tap is cooled / heated by means of a liquid heat exchanger connected directly or via the heat-conducting dielectric to the thermoelectric element.

45. The method, in particular according to claim 32, for maintenance-free, autonomous detection of fires and / or accidents in buildings and / or technical systems by means of at least one thermoelectric converter element, in particular according to one of claims 1 to 14, characterized in that the increasing Room temperature causes an electrical voltage on the element, which can be used directly to independently drive an alarm or other consumer.

46. The method, in particular according to claim 31, for waterless compressed air pre-cooling in high-speed drills or other rotating machines in medical technology or material processing by means of at least one thermoelectric converter element, in particular according to one of claims 1 to 14, characterized in that the inflowing Compressed air flows directly over the cold solder joints of the thermoelectric element, or through a heat exchanger connected to it via the heat-conducting dielectric.

47. Method, in particular according to one of claims 31 and / or 32, for the autonomous supply of remote objects or vehicles by means of at least one thermoelectric converter element, in particular according to one of claims 1 to 14, characterized in that a natural or artificial temperature difference over the element for Generation of electrical current is used, or vice versa the thermoelectric element is used for power supply for heating / cooling the interior.