JPH10164876A - Thermoelectric generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small thermoelectric generator whose efficiency is high, whose durability is high and which is provided with a heat-dissipating part of an air cooled type. SOLUTION: A thermoelectric element or one pair of face-shaped power generation units 1 in which a plurality of thermoelectric elements are connected in series are sandwiched between heat-dissipating parts 10, which are composed of fin parts 2 and of fans 4 and a heat input part 3, and every heat-dissipating part 10 is formed as an integrated structure in which every fan 4 is buried at the inside of every fin 2. As a result, the area of every heat-dissipating part 10 can be reduced to about 1/2 that in conventional cases, and the resistance of every fin to the flow of a forced wind due to every fan can be reduced. As a result, the quantity of airflow of every fan can be increased without changing the electric power of every fan, and every heat-dissipating part of high performance can be constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric generator for directly converting heat and electricity by utilizing a thermoelectromotive force generated when a temperature difference is applied to a thermoelectric material.

[0002]

2. Description of the Related Art Conventionally, batteries and engine generators have been mainly used as generators. However, in the case of a battery, it takes a long time to charge, and in the case of an engine generator using gasoline as a fuel, the operation noise is loud. Therefore, although the power generation efficiency is not as high as the former two, attention has been paid to a thermoelectric generator as a low-noise, charge-free power generation means.

A thermoelectric generator for performing direct conversion of heat and electricity by utilizing a thermoelectromotive force generated when a temperature difference is applied to a thermoelectric material is an emergency power supply, a portable power supply, a remote power supply, and waste heat recovery. It is attracting attention as a device. The performance of these generators increases in proportion to the square of the temperature difference across the thermoelectric material. Therefore, especially when a Bi-Te-based material having a relatively low heat-resistant temperature is used, the performance improvement of the power generator largely depends on the performance of the heat radiation part. A high-performance radiator can be realized by a water-cooling method, but the system becomes large and complicated,
In addition, since power supply to a pump or the like is required, it can be said that this is suitable for a considerably large-scale power generator. In particular, the number of outputs is 100W
The following generators require a high-performance, lightweight, compact air-cooled radiator.

Conventionally, the configuration described in the application related to Japanese Patent Application No. 8-149239 has been generally used as an air-cooled radiator for a thermoelectric generator. As shown in FIG. 3, the configuration of the power generator is such that the power generation unit 1 is sandwiched between the heat input unit 3 and the fin 2, and the fan 4 is installed on the outer surface of the fin 2.

[0005]

However, in the configuration of the heat radiating portion shown in FIG. 3, the heat radiating portion becomes larger as occupying more than half of the total volume of the generator, and the flow of the forced wind by the fan 4 is reduced by the fins 2. There was a problem that the airflow was hindered and the fan airflow was restricted. Therefore, a configuration of a more compact and high-performance radiator without changing the fan drive power or the like was required.

An object of the present invention is to provide a thermoelectric generator having a compact and high-performance air-cooling type heat radiating portion.

[0007]

Means for Solving the Problems In order to solve this problem, the radiator of the thermoelectric generator of the present invention has a volume as small as about 1/2 of the conventional one due to an integrated structure in which a fan is embedded inside the fin. In addition, since the resistance due to the fin portion is reduced, the fan airflow can be increased, so that the performance is higher than that of the related art.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1A is a vertical sectional side view of a thermoelectric generator according to Embodiment 1 of the present invention.
FIG. 1B is a front view of a radiator 10 of the thermoelectric generator. In FIG. 1A, reference numeral 1 denotes a planar power generation unit in which a pair of thermoelectric elements or a plurality of thermoelectric elements are connected in series, and is sandwiched between a fin portion 2 and a heat input portion 3;
Are installed on both sides. The fin portion 2 is an aluminum single plate having a large number of fins 2c on the outer surface of a disk-shaped substrate. As shown in FIG. 1 (b), a fin 2c is circularly low or absent in a central portion 2a of the fin portion 2, and a DC axial fan 4 is installed there. The fins 2 c are formed radially so that the forced air of the fan 4 flows radially from the center of the fan 4. 2b is the gap. The heat input unit 3 includes a heat conductive combustion chamber 5 made of aluminum or the like and a combustion unit 6 installed inside the combustion chamber 5. The combustion chamber 5 preferably has a fin structure on the inner wall. A fuel tank 7 is connected to the combustion chamber 5 via a nozzle 8 and a throat portion 9.

The operation of the thermoelectric generator configured as described above will be described below.

In FIG. 1, a commercially available butane gas was used as the fuel. The fuel gas injected from the nozzle 8 becomes a mixed gas containing air and burns in the combustion chamber 5 through the throat portion 9. The generated exhaust gas is discharged to the outside of the generator from the exhaust port at the upper part of the combustion chamber 5. The heat of combustion obtained in the heat input unit 3 is supplied to the surface of the planar power generation unit 1 on the high-temperature side of the thermoelectric element, and the low-temperature side of the thermoelectric element is in contact with the fin unit 2. Temperature difference between
Electric power is generated by thermoelectromotive force. Generation output is fan 4
When the size required for driving is reached, the fan 4 starts to rotate, the temperature difference generated in the thermoelectric element and the resulting thermoelectromotive force increase, and eventually reach a steady state.

When the generator of this embodiment was driven, it took about 30 seconds to drive two fans (12 V DC, 100 mA) and 5 to 8 minutes to stabilize the output (15 W). When the output was stable, the element surface temperature was 210 ° C. on the high temperature side and 90 ° C. on the low temperature side.

According to this embodiment, the heat exchange fin portion 2
The fan 4 and the fan 4 can form an integrated heat radiating portion 10, so that the volume of the heat radiating portion 10 can be significantly reduced. Further, since the forced wind of the fan 4 flows radially from the center of the fan 4 through the gap between the fins 2c, the resistance due to the fins 2c decreases, so that the fan airflow can be increased. as a result,
The ability of the fan can be utilized to the maximum, and the performance of the heat radiating unit 10 can be improved. At the same time, the outlet temperature of the heat-exchanged air can be kept low, so that safety can be ensured.

In FIG. 1, the gas tank is installed at the bottom of the generator and the fuel gas is preheated by the heat from the fins. However, the tank may be externally mounted so that the tank can be easily replaced. In that case, it is desirable that the fuel gas be preheated by combustion heat or exhaust heat before being sent to the nozzle.

In this case, butane gas is used as the fuel, but it is of course possible to use propane gas, natural gas and the like. Further, when a liquid fuel such as alcohols is used, the handling of the generator becomes inconvenient, but the nozzle and the throat become unnecessary, and a simpler configuration can be realized.

Further, if catalytic combustion heat is used as the heat source of the heat input section, heat can be input uniformly in a plane, so that a more efficient power generator can be constructed. Further, a generator as a means for recovering a part of the waste heat by using waste heat of a fuel cell, an engine, or the like may be used.

(Embodiment 2) FIG. 2A is a vertical sectional side view showing a configuration of a heat radiating portion 10 of a thermoelectric generator according to Embodiment 2 of the present invention, and FIG. It is a front view of the heat radiation part 10 of a generator. In FIG. 2, reference numeral 2 denotes an aluminum fin, 4 denotes a DC axial fan, and 10 denotes a motor of the fan. The motor part 11 is a heat insulating layer 1
2, it is embedded inside the fin portion 2. For the heat insulating layer 12, ceramics such as alumina wool can be used. In addition, we provide air layer of several millimeters,
It may be a heat insulating layer.

The operation of the thermoelectric generator having the above-described structure of the heat radiator is the same as that of the first embodiment except for the following points.

That is, the structure in which the heat insulating layer 12 is provided between the motor unit 11 and the fin unit 2 enables the motor unit 11 to be heated to 70 ° C. even when the temperature of the center of the fin unit is 100 ° C. Therefore, the durability of the fan 4 can be improved.

Even if the size and shape of the power generator change, the present invention can be applied by optimizing the thickness of the peripheral portion and the central portion of the fin bottom plate and the thickness of the heat insulating layer.

[0021]

As described above, according to the present invention, in a thermoelectric generator using combustion heat including catalytic combustion heat or waste heat as a heat source, a compact configuration of a highly efficient and highly durable radiator can be realized. Therefore, the thermoelectric generator can be reduced in size and weight or can have higher performance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a thermoelectric generator according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a thermoelectric generator according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional thermoelectric generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Surface power generation unit (thermoelectric element) 2 Fin part 3 Heat input part 4 Fan 5 Combustion chamber 6 Burning part 7 Fuel tank 8 Nozzle 9 Throat part 10 Heat radiating part 11 Motor part 12 Heat insulation layer

Claims (3)

[Claims] 1. A heat input section for inputting heat, a heat radiating section having a fin portion and a fan, and a power generation unit for performing thermoelectric conversion using a thermoelectric element sandwiched between the heat radiating section and the heat input section. And a fuel supply means for supplying fuel, which supplies heat directly to the high-temperature side of the thermoelectric element, and at the same time, air-cools a radiating portion in contact with the radiating side of the thermoelectric element to perform thermoelectric generation. A thermoelectric generator, wherein all or a part of the fan is housed inside a fin portion of the heat radiating portion. 2. The fin of the fin portion is formed radially, and the fan is arranged in a portion where the fin at the center of the radiation is absent or low.
A thermoelectric generator as described. 3. The thermoelectric generator according to claim 1, wherein the fan is an axial fan, and a heat insulating means is provided between the motor portion of the fan and the fin portion.