JPH11274575A - Thermoelectric power generation system - Google Patents

Abstract

(57) [Problem] To provide a thermoelectric generator capable of adjusting a flow rate of a heat medium supplied to a heat exchange block and preventing a variation in power generation between thermoelectric modules. SOLUTION: A thermoelectric generator 20 in which a plurality of thermoelectric modules 30, a high-temperature side heat exchange block 40 and a low-temperature side heat exchange block 42 are stacked, and a heated heat medium which communicates with a flow path of the high-temperature side heat exchange block In the thermoelectric power generation system having the high-temperature side circulation path 50 in which the heat is circulated, and the low-temperature side circulation path 60 communicating with the low-temperature side heat exchange block and circulating the cooled heat medium, the high-temperature side circulation path includes a thermoelectric generator. A branch pipe 52 that branches off on the upstream side and communicates with the flow path of each high-temperature side heat exchange block and merges again on the downstream side. A branch pipe 62 that communicates with the flow path of the heat exchange block and rejoins downstream is provided with a valve device 70 for adjusting the flow rate of the heat medium in at least one of the branch pipes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a thermoelectric power generation system that generates electric power by utilizing the Seebeck effect.

[0002]

2. Description of the Related Art In recent years, thermoelectric power generation systems that generate electric power by utilizing waste heat discharged from factories, refuse incineration plants and power plants, and thermal energy such as geothermal heat have been developed.
As shown in FIG. 4, a thermoelectric generator (20) for performing thermoelectric generation includes a high-temperature side circulation path (50) through which a heated heat medium circulates, The low-temperature side circulation path (60) through which the medium circulates is connected and connected.

As shown in FIG. 3, a thermoelectric generator (20)
P-type thermoelectric elements (32) and n-type thermoelectric elements (34) arranged alternately
As shown in FIG. 4, a thermoelectric module (30) connected by electrodes (36) so as to be electrically in series with one another has a heat exchange block (40) on one electrode surface on the high-temperature side, and another electrode surface on the other electrode surface. Are arranged so as to face the heat exchange block (42) on the low temperature side. The heat exchange block is made of a material having excellent heat conductivity, and has a flow passage through which a heat medium flows.
The heat exchange blocks (40) and (42) and the thermoelectric module (30) are stacked in a plurality of stages to form a thermoelectric generator (20) according to the required performance as shown in FIG.

[0004] The high-temperature side circulation path (50) is provided with a heat medium heated by heat exchange with a heating source (58) to supply means such as a pump.
The flow path circulated by (54), branches off at the upstream side of the thermoelectric generator (20), communicates with the flow path of each high-temperature side heat exchange block (40), and passes through the inside of the heat exchange block (40). As a result, they merge again on the downstream side of the thermoelectric generator (20).

[0005] The low-temperature side circulation path (60) is provided with a heat medium cooled by heat exchange with a cooling source (68) to supply means such as a pump.
The flow path circulated by (64), branches off from the upstream side of the thermoelectric generator (20), communicates with the flow path of each low-temperature side heat exchange block (42), and passes through the inside of the heat exchange block (40). As a result, they merge again on the downstream side of the thermoelectric generator (20).

[0006] The heated heat medium is transferred to a high-temperature side heat exchange block.
(40) to heat the one electrode surface of the thermoelectric module (30), and supply the cooled heat medium to the low-temperature side heat exchange block (42) to cool the other electrode surface of the thermoelectric module (30). Upon cooling, a potential difference occurs between the thermoelectric element pairs due to the so-called Seebeck effect, and power generation is performed.

[0007]

The amount of power generated by the thermoelectric module (30) is proportional to the square of the given temperature difference. Therefore, in the thermoelectric power generation system, in order to increase the power generation efficiency, it is necessary to adjust the flow rate of the heat medium supplied to the thermoelectric power generation device (20). Therefore, as shown in FIG. 4, a valve device (7
There is a thermoelectric power generation system (10) in which 8) is provided to adjust the flow rate of the heat medium. In this system, the total amount of the heat medium supplied to the thermoelectric generator can be adjusted, but the amount of the heat medium supplied to each heat exchange block cannot be adjusted.

[0008] For this reason, there has been a problem that the amount of the heat medium supplied to each heat exchange block varies, resulting in a difference in the amount of power generated by the thermoelectric module. Further, since the heat exchange block located at the outermost position is in direct contact with the device housing and the outside air and is cooled under the influence of the outside air, when supplying the same amount of heat medium as the other heat exchange blocks, There was a problem with different temperatures.

An object of the present invention is to provide a thermoelectric generator capable of controlling the flow rate of a heat medium supplied to a heat exchange block, preventing variations in the amount of power generation between thermoelectric modules, and efficiently generating power. It is to be.

[0010]

In order to solve the above problems, the present invention provides a thermoelectric module in which a p-type thermoelectric element (32) and an n-type thermoelectric element (34) are electrically connected in series by an electrode (36).
(30), a high-temperature side heat exchange block (40) in which a flow path through which a heated heat medium flows is formed, and a low-temperature side heat in which a flow path through which a heat medium cooled inside is formed. The thermoelectric generator (20) in which a plurality of exchange blocks (42) are stacked and the flow path of the high-temperature side heat exchange block (40) communicate with each other, and the heat medium heated by heat exchange with the heating source (58) circulates. Communicates with the high temperature side circulation path (50) and the low temperature side heat exchange block (42),
And a low-temperature side circuit (60) through which a heat medium cooled by heat exchange with (68) is circulated, and the high-temperature side circuit (50) is located upstream of the thermoelectric generator (20). A branch pipe (52) that branches off on the side and communicates with the flow path of each high-temperature side heat exchange block (40) and joins again downstream of the thermoelectric generator (20), and has a low-temperature side circulation path (60 ) Is the thermoelectric generator (2
0), and has a branch pipe (62) that communicates with the flow path of each heat exchange block (42) and joins again downstream of the thermoelectric generator (20). At least one of which is provided with a valve device (70) for adjusting the flow rate of the heat medium.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a thermoelectric power generation system (10) is as follows.
As shown in FIG. 1, the thermoelectric generator (20) includes a high-temperature circuit (50) through which a heated heat medium flows, and a low-temperature circuit (60) through which a cooled heat medium flows. .

Thermoelectric generator The thermoelectric generator (20) is formed by stacking heat exchange blocks (40) and (42) and a thermoelectric module (30). Thermoelectric module
As shown in FIG. 3, (30) is constructed by alternately arranging p-type thermoelectric elements (32) and n-type thermoelectric elements (34) and electrically connecting them in series by electrodes (36), and is used. The number of thermoelectric elements is determined according to the required performance.

The heat exchange blocks (40) and (42) are made of a material having excellent heat conductivity (eg, copper, silver, aluminum, brass, etc.).
And is formed in a flat plate shape. Heat exchange block (4
0) A channel (not shown) through which the heat medium flows is formed inside (42). Both ends of the flow path are circulated through a heat medium circulation path (50) (6
0).

Also, as shown in FIG.
Temperature sensors are provided in (40) and (42). A thermocouple (80) can be exemplified as a temperature sensor.
A thermocouple such as Allomer is used. The thermocouple (80) can be attached by forming an attachment hole (82) on the side surface of the heat exchange block (40) (42) and inserting the attachment hole (82). The detection value of the temperature sensor is transmitted to a control unit (94) described later.

A plurality of the heat exchange blocks (40) and (42) and the thermoelectric module (30) are alternately stacked so that the heat exchange blocks are located on the outermost side, and are tightened at a predetermined pressure. (20) is produced. In addition,
When using a thermoelectric module with exposed electrodes, and when using the aforementioned copper, silver, aluminum, brass, etc. as the heat exchange block, since these materials are conductive, the heat exchange block and the thermoelectric module It is necessary to achieve electrical insulation between the two. In such a case, an insulating plate made of an electrically insulating material such as alumina may be arranged on the surface of the heat exchange block. When it is necessary to increase the heat transfer efficiency between the thermoelectric module and the heat exchange block, a heat conductive grease may be applied to these surfaces.

The stacked heat exchange blocks are alternately referred to as a low-temperature heat exchange block (42) and a high-temperature heat exchange block (40) from below. In this embodiment, an odd number of heat exchange blocks are used, and the outermost heat exchange blocks are the low-temperature side heat exchange blocks (42) and (42). This is because the outermost heat exchange block is in direct contact with the device casing and the outside air, so it is better to arrange the low-temperature side heat exchange blocks (42) and (42) with the smaller temperature difference from the outside air on the outermost side. This is because the effect of heat loss is small.

High-temperature side circulation path The high-temperature side circulation path (50) is used to transfer the heated heat medium to the thermoelectric generator (2).
In the flow path supplied to the high-temperature side heat exchange block (40) of (0), as shown in FIG. 1, heat exchange is performed with a heating source (58) such as a factory in a flow path through which a heat medium flows. Heat exchange part (56),
A feeding means (54) such as a pump for feeding a heat medium is provided. As described above, the high-temperature side circulation path (50) has a thermoelectric generator (20) connected in its flow path, and has branch pipes (52 )have. (52a) is an upstream branch pipe, and the branch pipe (52a) is connected so as to communicate with the upstream side of the flow path of the high-temperature side heat exchange block (40) of the thermoelectric generator (20). Also, (52b) is a downstream branch pipe, the branch pipe (52b) is a heat exchange block (40)
Are connected so as to communicate with the downstream side of the flow path. As shown, pressure headers (90) and (90) are provided at the branch portions of the upstream and downstream branch pipes (52a) and (52b), and the heat medium is supplied to each of the branch pipes (52a) and (52b). It is desirable to circulate at an even pressure. The pressure header (90) may be provided only on one of the upstream side and the downstream side.

The branch pipe (52) is provided with a valve device (70) for adjusting the flow rate of the heat medium flowing through the branch pipe. Valve device (70)
Need only be provided in at least one of the upstream and downstream branch pipes. In FIG. 1, the valve device is provided in the upstream branch pipe (52a). The control of the valve device (70) is performed by a control unit (94) described later.

When the feeding means (54) is operated, the heat exchange section (5)
The heat medium heated in 6) is sent to the pressure header (90),
The heat is supplied from the pressure header (90) to the flow path of each high-temperature heat exchange block (40) through the upstream branch pipe (52a), and heat exchange is performed with the high-temperature heat exchange block. The heat exchanged heat medium passes through the pressure header (90) from the downstream branch pipe (52b), merges again, and is sent to the heat exchange section (56). The heated heat medium thus circulates in the high-temperature side circulation path (50).

The low-temperature side circulation path low-temperature side circulation path (60), thermoelectric generator the cooled heat medium
As shown in FIG. 1, an air-cooled or water-cooled cooling source (68) is provided in the flow path for supplying to the low-temperature side heat exchange block (42) of (20). The heat exchange section (6
6), and a feeding means (64) such as a pump for feeding a heat medium. The low-temperature side circulation path (60) has a thermoelectric generator (20) connected in its flow path, like the high-temperature side circulation path (50),
It has branch pipes (62) that branch on the upstream side and the downstream side, respectively, of the thermoelectric generator (20). (62a) is an upstream branch pipe,
The branch pipe (62a) is connected to communicate with the upstream side of the flow path of the low-temperature side heat exchange block (42) of the thermoelectric generator (20).
Further, (62b) is a downstream branch pipe, and the branch pipe (62a) is connected so as to communicate with the downstream side of the flow path of the heat exchange block (42). As described above, the upstream and downstream branch pipes (6
It is desirable to provide pressure headers (92) and (92) at the branch portions of 2a) and (62b) so that the heat medium is circulated through the branch pipes (62a) and (62b) at an equal pressure. The pressure header (92) may be provided only on one of the upstream side and the downstream side.

The branch pipe (62) is provided with a valve device (70) for adjusting the flow rate of the heat medium flowing through the branch pipe. Valve device (70)
Need only be provided in at least one of the upstream and downstream branch pipes. In FIG. 1, the valve device is provided in the upstream branch pipe (62a). The control of the valve device (70) is performed by the control unit (94).

When the feeding means (64) is operated, the heat exchange section (6)
The heat medium cooled in 6) is sent to the pressure header (92),
The heat is supplied from the pressure header (92) to the flow path of each low-temperature side heat exchange block (42) through the upstream branch pipe (62a), and heat exchange is performed with the low-temperature side heat exchange block. The heat exchanged heat medium passes through the pressure header (92) from the branch pipe (62b) on the downstream side, merges again, and is sent to the heat exchange section (66). The cooled heat medium thus circulates in the low temperature side circulation path (60).

The control unit control section (94), as shown in FIG. 2, the valve device (70) is electrically connected (thermocouple (80) in this embodiment) a temperature sensor, the thermocouple (80 The opening degree of the valve device is adjusted based on the detection value of (2). The control section (94) stores in advance data relating to the operating temperature range of the high-temperature side heat exchange block (40) and the low-temperature side heat exchange block (42) according to the required performance of the thermoelectric module (30).

The control of the valve device by the control section (94) is performed as follows. When the temperature of the high-temperature side heat exchange block (40) detected by the thermocouple (80) becomes lower than the operating temperature range, the opening of the valve device (70) of the heat exchange block (40) is increased, Increase the flow rate of the heating medium. Conversely, when the temperature of the high-temperature side heat exchange block (40) becomes higher than the operating temperature range, the opening of the valve device (70) of the heat exchange block (40) is reduced, and the flow rate of the heat medium is reduced. Let it. In addition, thermocouple (8
When the temperature of the low-temperature side heat exchange block (42) detected by (0) becomes higher than the operating temperature range, the heat exchange block (42)
The flow rate of the heat medium is increased by increasing the opening of the valve device (70) of (42). Conversely, when the temperature of the low-temperature side heat exchange block (42) becomes lower than the operating temperature range, the heat exchange block
The flow rate of the heat medium is reduced by reducing the opening of the valve device (70) of (42).

As described above, the thermoelectric power generation system of the present invention
(10) adjusts the flow rate of the heat medium supplied to each heat exchange block (40) (42) individually by the valve device (70) based on the temperature of the heat exchange block detected by the temperature sensor. The temperature of the heat exchange block is maintained in a desired operating temperature range. Therefore, the power generation amount of the thermoelectric module (30) can be kept in an optimal state.

In the above embodiment, the opening of the valve device is adjusted based on the temperature detected by the temperature sensor. However, the opening of the valve device may be adjusted based on the power generation of each thermoelectric module. it can. In this case, the power generation amount of each thermoelectric module is measured, and the opening degree of the valve device of the heat exchange block that sandwiches the thermoelectric module with low power generation is increased to increase the flow rate of the heat medium. As a result, the temperature difference given to the thermoelectric module increases, and the desired power generation is maintained.

In the above embodiment, each of the branch pipes (52) (62)
Although the valve device (70) is provided in the first embodiment, the valve device may be provided only in the branch pipe communicating with the outermost heat exchange block among the stacked heat exchange blocks. This is because the outermost heat exchange block has only one side in contact with the thermoelectric module, and the opposite surface is in direct contact with the device housing and the outside air, and therefore has a different temperature balance from the other heat exchange blocks.

[0028]

According to the thermoelectric power generation system of the present invention, the flow rate of the heat medium supplied to each heat exchange block can be individually adjusted by the valve device, so that the temperature of the heat exchange block can be adjusted to a desired operating temperature. Area can be maintained. In particular, when the temperature of each heat exchange block is measured by a temperature sensor and the opening degree of the valve device is adjusted based on the measured temperature, more accurate temperature control of each heat exchange block can be performed. .

Since the temperature of the heat exchange block can be maintained in a desired operating temperature range, a desired temperature difference can be given to the thermoelectric module, and efficient power generation can be performed.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a thermoelectric power generation system of the present invention.

FIG. 2 is an explanatory diagram of a control unit.

FIG. 3 is a perspective view of a thermoelectric module.

FIG. 4 is an explanatory diagram of a conventional thermoelectric power generation system.

[Explanation of symbols]

 (10) Thermoelectric generator system (20) Thermoelectric generator (30) Thermoelectric module (40) High-temperature heat exchange block (42) Low-temperature heat exchange block (52) Branch pipe (62) Branch pipe (70) Valve unit

Claims (4)

[Claims] 1. A p-type thermoelectric element (32) and an n-type thermoelectric element (34)
The thermoelectric module (30) electrically connected in series by the electrode (36), the high-temperature side heat exchange block (40) in which the flow path of the heat medium heated inside is formed, and the inside is cooled. A thermoelectric generator (20) in which a plurality of low-temperature side heat exchange blocks (42) in which a flow path of the heat medium flows are formed,
Communicates with the flow path of the high-temperature side heat exchange block (40) and has a heating source (58)
The high-temperature side circulation path (50) through which the heat medium heated by the heat exchange with the heat-exchanger circulates, and the flow path of the low-temperature side heat exchange block (42) communicate with the cooling source (68). In the thermoelectric power generation system including the low-temperature side circulation path (60) through which the heat medium circulates, the high-temperature side circulation path (50) branches off on the upstream side of the thermoelectric generation device (20) to exchange each high-temperature side heat exchange. A branch pipe communicating with the flow path of the block (40) and rejoining downstream of the thermoelectric generator (20)
(52), the low-temperature side circulation path (60) is branched on the upstream side of the thermoelectric generator (20) and communicates with the flow path of each low-temperature side heat exchange block (42), and the thermoelectric generator ( 20) has a branch pipe (62) rejoining downstream of at least one of the branch pipes.
And a valve device (70) for adjusting the flow rate of the heat medium. 2. The thermoelectric power generation system according to claim 1, wherein the valve device (70) is provided in a branch pipe communicating with the outermost heat exchange block. 3. A temperature sensor for detecting the temperature of the heat exchange block is provided in the heat exchange blocks (40) and (42), and a valve device (7) is provided.
The thermoelectric power generation system according to claim 1, wherein 0) is controlled based on a detection value of a temperature sensor. 4. The thermoelectric power generation system according to claim 3, wherein the temperature sensor is a thermocouple (80).