Thermoelectric generator system and thermoelectric generation method

Abstract

To provide a thermoelectric generator system and a thermoelectric generation method which can efficiently improve output by a simple system by utilizing an exhaust heat source at low temperature.SOLUTION: A thermoelectric generator system of the present invention comprises, in the thermoelectric generator system comprising a thermoelectric generator which generates power by a plate-like thermoelectric element, the thermoelectric generator comprising a heat source which heats up one surface of the thermoelectric element and a cooling fin of an air-cooling system which cools the other surface of the thermoelectric element; a compressor which compresses the exhaust air after cooling the cooling fin, a compression chamber which stores gas at high temperature and high pressure compressed by the compressor to be used as the heat source; and an expansion valve which reduces pressure of gas at low temperature and high pressure from the compression chamber. The thermoelectric generator system is constituted to cool the cooling fin by gas at low temperature from the expansion valve.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a thermoelectric generator system and a method for generating thermoelectric power. [Background technology]

[0002] In air-cooled thermoelectric generators equipped with thermoelectric elements, the exhaust heat source is sometimes used as the heating section of the thermoelectric elements. When the exhaust heat source is below a certain temperature (for example, 70°C), the output of the thermoelectric generator drops significantly, and in order to obtain high output, it is necessary to install more thermoelectric elements, which increases the scale and cost of the equipment.

[0003] Patent Document 1 discloses a thermoelectric generator using a compressor and a vortex tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-158228 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not consider how to improve the efficiency of the entire system, and it is desirable to reduce energy loss with a simple system. It is also desirable to effectively utilize low-temperature waste heat sources below a certain temperature (e.g., 70°C) and improve the output of thermoelectric generators.

[0006] An object of the present invention is to provide a thermoelectric generator system and a thermoelectric power generation method that utilize a low-temperature waste heat source and are capable of efficiently increasing output with a simple system. [Means for solving the problem]

[0007] The thermoelectric generator system of the present invention is a thermoelectric generator system equipped with a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, the thermoelectric generator having a heat source that heats one side of the thermoelectric element and an air-cooled cooling fin that cools the other side of the thermoelectric element, a compressor that compresses the air exhausted after cooling the cooling fin, a compression chamber that stores high-temperature, high-pressure gas compressed in the compressor and uses it as the heat source, and an expansion valve that reduces the pressure of the low-temperature, high-pressure gas from the compression chamber, and is configured to cool the cooling fin with low-temperature gas from the expansion valve.

[0008] Alternatively, the thermoelectric generator system of the present invention is a thermoelectric generator system including a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, the thermoelectric generator having a heat source that heats one side of the thermoelectric element and an air-cooled cooling fin that cools the other side of the thermoelectric element, an exhaust stack that extends in the vertical direction and collects air after cooling and discharges it upward, a cylindrical compressor that takes in the exhaust air from the top of the exhaust stack after cooling the cooling fin and compresses it, a compression chamber that stores high-temperature, high-pressure gas compressed in the cylindrical compressor and uses it as the heat source, and an expansion valve that reduces the pressure of the low-temperature, high-pressure gas from the compression chamber, and is configured to cool the cooling fin with low-temperature gas from the expansion valve.

[0009] Alternatively, the thermoelectric generator system of the present invention is a thermoelectric generator system including a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, the thermoelectric generator system including: a first thermoelectric generator having a heat source that heats one side of the thermoelectric element and an air-cooled cooling fin that cools the other side of the thermoelectric element; an exhaust stack that extends in the vertical direction and collects air after cooling and discharges it upward; a cylindrical compressor that takes in the exhaust air after cooling the cooling fin through an intake at the top of the exhaust stack and compresses it; a compression chamber that stores high-temperature, high-pressure gas compressed in the cylindrical compressor and uses it as the heat source for the first thermoelectric generator; and an expansion valve that reduces the pressure of the low-temperature, high-pressure gas from the compression chamber, wherein the cooling fin is cooled by low-temperature gas from the expansion valve; and a heating means that heats the inside of the exhaust stack between the thermoelectric generator and the intake in the vertical direction.

[0010] Alternatively, the power generation method for a thermoelectric generator system of the present invention is a power generation method for a thermoelectric generator system including a thermoelectric generator that generates power using a plate-shaped thermoelectric element, the power generation method including a power generation step of generating power using the thermoelectric generator having a heat source that heats one side of the thermoelectric element and an air-cooled cooling fin that cools the other side of the thermoelectric element, a compression step of compressing the exhaust air after cooling the cooling fin with a cylindrical compressor, a heating step of heating one side of the thermoelectric element with a compression chamber that stores high-temperature, high-pressure gas compressed in the cylindrical compressor, an exhaust step of reducing the pressure of the low-temperature, high-pressure gas from the compression chamber, and a cooling step of cooling the cooling fin with low-temperature gas from the exhaust step. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a thermoelectric generator system and a thermoelectric power generation method that utilize a low-temperature exhaust heat source and are capable of efficiently improving output with a simple system. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows the configuration of a thermoelectric generator according to a first embodiment. [Figure 2] 1 shows the configuration of a thermoelectric generator system according to a first embodiment. [Figure 3] 1 shows a configuration diagram of a cylindrical compressor of a thermoelectric generator system according to a first embodiment of the present invention. [Figure 4] 2 shows a cross-sectional view taken along line AA of a cylindrical compressor of the thermoelectric generator system according to the first embodiment. FIG. [Figure 5] 3 is an explanatory diagram of the operation of the cylinder-type compressor according to the first embodiment. FIG. [Figure 6] 1 shows the volume and temperature change of the compression chamber of the thermoelectric generator system according to the first embodiment. [Figure 7] 1 shows an operation flow of the thermoelectric generator system according to the first embodiment. [Figure 8] 1 shows the configuration of a thermoelectric generator system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, with reference to the drawings, an embodiment of the thermoelectric generator of the present invention will be described. The embodiment is an example for explaining the present invention, and for clarity of explanation, some omissions and simplifications have been made. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0014] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings. [Example]

[0015] The air-cooled thermoelectric generator of this embodiment will be described using FIG. 1. The configuration of the thermoelectric generator according to this embodiment 1 is shown. A heat exchanger 3, which serves as a heat source, and cooling fins 2 are arranged to sandwich a thermoelectric element 1. For example, a Peltier module or the like is used for the thermoelectric element 1, and power is generated by the temperature difference between the two sides (high-temperature side and low-temperature side). In this embodiment, the heat exchanger 3 is arranged as the heat source, but other heat sources may be used. A high-temperature medium such as hot water is circulated through the heat exchanger 3, which has piping, to heat one side of the thermoelectric element 1. In addition, an air-cooled cooling fin 2 is arranged on the other side of the thermoelectric element 1. Air is circulated through this cooling fin 2 to cool the other side of the thermoelectric element 1. This configuration creates a temperature difference between the two sides of the thermoelectric element 1, allowing power to be generated.

[0016] 2 shows the configuration of the thermoelectric generator system according to Example 1. The thermoelectric generator system mainly includes a thermoelectric generator having a plate-shaped thermoelectric element 1, a cooling fin 2 for air-cooling one side of the thermoelectric element 1, and a compression chamber 17 as a heat source for heating the other side of the thermoelectric element 1.

[0017] In addition, incoming air 5 passes through cooling fins 2, cooling them and air-cooling one side of thermoelectric element 1. After cooling, exhaust air 6 is sent to compressor 9 and compressed to obtain high-temperature, high-pressure gas. This high-temperature, high-pressure gas is stored in compression chamber 17, which heats the other side of thermoelectric element 1. Thermoelectric element 1 generates electricity using this temperature difference between both sides.

[0018] Next, after the thermal energy of the high-temperature, high-pressure gas in the compression chamber 17 is used to generate electricity by the thermoelectric element 1, that is, the cooled compressed gas 12 is sent to the expansion valve 11 to reduce the pressure. This low-temperature exhaust gas 13 is used as inflow air 5 to cool the cooling fins 2.

[0019] Here, the temperature of the discharged air 6 after cooling has risen; in other words, the temperature of the air before compression has risen, so the temperature can be further increased by compression by the compressor 9, increasing the effect of heating the other side of the thermoelectric element 1. Since the compression chamber 17 storing the high-temperature, high-pressure gas compressed by the compressor 9 is used as the heat source for the thermoelectric element 1, there is little energy loss. Since the pressure of the compressed gas 12 after cooling is reduced by the expansion valve 11, the temperature is further reduced. By using this low-temperature air to cool the thermoelectric element 1, the cooling effect of the cooling fins 2 can be increased. As described above, the configuration has little energy loss, and the cooling effect of air cooling the thermoelectric element 1 is increased, and the heating effect of heating the thermoelectric element 1 is also increased, so the temperature difference is large and the power generation output of the thermoelectric generator can be increased.

[0020] FIG. 3 shows a configuration diagram of a cylindrical compressor of the thermoelectric generator system according to the first embodiment. The cylindrical compressor includes a piston 20 and a cylinder 21, and a drive unit 22 that moves the piston 20. An intake check valve 23 is provided in the intake path that takes in the incoming air 5 into the cylinder 21. A compression chamber 17 that stores compressed air is provided on the side of the cylindrical compressor 9 opposite the drive unit. This compression chamber 17 serves as the heat source for the thermoelectric element 1. The thermoelectric element 1 is arranged around the compression chamber 17. Furthermore, cooling fins 2 are arranged around the thermoelectric element 1. After the compressed high-temperature, high-pressure gas heats the thermoelectric element 1 and generates electricity, the high-temperature, high-pressure gas is cooled. The cooled gas is discharged through an exhaust system. The exhaust system includes an exhaust valve S and an exhaust expansion valve.

[0021] FIG. 4 shows an AA cross-sectional view of the cylindrical compressor of the thermoelectric generator system according to the first embodiment. Four thermoelectric elements 1 are provided on each side of the square compression chamber 17. Cooling fins 2 are provided on the side of the thermoelectric elements 1 opposite the compression chamber. In this embodiment, the compression chamber 17 is square and four thermoelectric elements 1 are arranged, but this is not limited to this. As shown in FIG. 4, the compression chamber 17 is located in the center, the thermoelectric elements 1 are located around it, and the cooling fins 2 are located around those. Furthermore, although the cooling fins 2 are arranged radially, they may also be arranged to extend in all directions.

[0022] 5A and 5B are diagrams illustrating the operation of the cylinder-type compressor according to the present embodiment 1. Fig. 5A shows the intake operation, Fig. 5B shows the compression power generation operation, and Fig. 5C shows the exhaust operation.

[0023] FIG. 5(a) shows the operation of the thermoelectric generator system during intake operation. The discharge valve S of the post-compression discharge system is "closed," and the expansion valve 11 is "closed." First, the piston 20 is pulled. In other words, it moves to the left in the drawing (toward the drive unit), thereby drawing air into the compressor 9. An intake check valve 23 is installed in this intake system, which allows air to flow in the intake direction and prevents it from flowing in the opposite direction.

[0024] The fluid in the post-compression discharge system may be shut off by the discharge valve S, and the expansion valve 11 may be set to a fixed opening. In other words, the expansion valve 11 may be opened and closed, or a needle valve may be used with a small opening, or a small diameter orifice or the like may be used with a fixed opening.

[0025] Figure 5(b) shows the operation of the thermoelectric generator system during compression power generation. The discharge valve S is closed, and the piston 20 is pushed. In other words, by moving the piston 20 to the right in the figure (opposite the drive unit side, toward the thermoelectric generator side), the air in the cylinder 21 is compressed and stored in the compression chamber 17. The compressed high-temperature, high-pressure gas heats one side of the thermoelectric element 1 installed around the compression chamber 17, while the other side is cooled by the cooling fin 2, causing the thermoelectric element 1 to generate electricity. In this way, the compressed high-temperature, high-pressure gas is stored in the compression chamber 17 and used as a heat source as is, minimizing energy loss and improving power output with a simple configuration. During this process, thermal energy is converted into electrical energy, and the high-temperature, high-pressure gas in the compression chamber 17 is cooled.

[0026] Figure 5(c) shows the operation of the thermoelectric generator system during exhaust operation. The exhaust valve S is opened to exhaust the cooled gas from the compression chamber 17. The air is decompressed by the expansion valve 11 arranged in the exhaust system and is exhausted. This decompression further reduces the temperature of the exhaust air, which is then used to cool the cooling fins 2. Using the cooled exhaust air for cooling in this way increases the cooling effect and increases the power generation output.

[0027] As described above, the use of a cylindrical compressor 9 allows for increased output with a simple configuration that requires less power. Also, the use of the compression chamber 17 as a heat source reduces energy loss. Furthermore, the cooled, low-temperature exhaust air can be used to cool the thermoelectric generator, improving power generation output.

[0028] The processes of intake, compression, power generation, etc. will be described with reference to Figures 6 and 7. Figure 6 shows the volume and temperature changes of the compression chamber of the thermoelectric generator system according to this embodiment 1. Figure 7 shows the operation flow of the thermoelectric generator system according to this embodiment 1.

[0029] In the intake step S1, at point P1, the retraction of the piston causes the discharge air 6 to be drawn into the cylinder 21 and compression chamber 17 of the compressor 9. At this time, the discharge valve S is "closed" and the expansion valve 11 is "closed." The discharge air 6 cools the cooling fins 2 of the thermoelectric generator and increases in temperature. The higher the temperature before being taken into the compressor 9, the higher the temperature can be during compression.

[0030] In the compression power generation step S2, the temperature and pressure are then raised 31 from point P1 to point P2. The pushing action of the piston causes the gas to be compressed as high-temperature, high-pressure gas into the compression chamber 17 of the compressor 9. At this time, the discharge valve S is "closed" and the expansion valve 11 is "closed." A heating step is carried out in which this high-temperature, high-pressure gas heats one side of the thermoelectric element 1. At this time, a cooling step is also carried out in which the cooling fins 2 of the thermoelectric generator are cooled, and power is generated by carrying out the heating step and cooling step.

[0031] During the temperature reduction process 32, power generation is performed until the temperature reaches a predetermined value. The high-temperature, high-pressure gas is cooled during power generation, and the power generation output gradually decreases. A predetermined temperature is set, and once the temperature is reached, the process moves to the next step. The predetermined temperature can be set by taking into consideration the efficiency balance of the entire system. The timing to move to the next step can be determined by measuring the temperature of the compression chamber 17 of the compressor 9 and observing the decrease in power generation output. It is also possible to obtain actual data and manage the time it takes for the temperature to reach the predetermined value after compression.

[0032] In the exhaust step S3, the temperature is reduced and the pressure is reduced 33. At this time, the exhaust valve S is open and the expansion valve 11 is open. The above-mentioned high-pressure gas whose temperature has been reduced is depressurized by the expansion valve 11, and the temperature is further reduced by this reduction in pressure, and reaches point P4. This cooled gas is used to cool the cooling fins 2 of the thermoelectric generator. Then, the process returns to the above-mentioned intake step S1, and the cooled exhaust air 6 is taken into the cylinder 21 and compression chamber 17 of the compressor 9, and power generation is repeated.

[0033] The fluid in the discharge system after compression may be shut off by the discharge valve S, and the expansion valve 11 may be set to a fixed opening. In other words, the expansion valve 11 may be opened and closed, or a needle valve may be used with a small opening, or a small diameter orifice may be used with a fixed opening. [Example]

[0034] FIG. 8 shows the configuration of a thermoelectric generator system according to the second embodiment. The exhaust stack 4 extends vertically and collects cooled air and discharges it upward. A thermoelectric generator (first thermoelectric generator) is horizontally disposed on one side of the exhaust stack 4. An intake port is provided at the top of the exhaust stack 4 for introducing the exhaust air, after cooling the cooling fins, into the cylindrical compressor. This heated exhaust air is taken into the cylindrical compressor 9, and the high-temperature, high-pressure gas compressed by the compressor 9 can be stored in the compression chamber. The exhaust system from the compressor passes through an expansion valve 11 and is recirculated by a distribution damper 14 as cooling air for the cooling fins 2. Here, the distribution damper 14 discharges the low-temperature, low-pressure gas delivered from the expansion valve 11 to the outside of the exhaust stack 4 if its temperature is higher than that of the inflow air 5. However, if the temperature of the low-temperature, low-pressure gas delivered from the expansion valve 11 is lower than that of the inflow air 5, the gas is taken into the exhaust stack 4 and used as cooling air for the cooling fins 2.

[0035] Another thermoelectric generator (second thermoelectric generator) is located on the other horizontal side of the exhaust stack 4. The cooling fins 2 and thermoelectric element 1 are located on the inner surface of the exhaust stack 4, and a heat exchanger 3 is installed on the outer surface of the exhaust stack 4 corresponding to the cooling fins 2 and the thermoelectric element 1 as a heat source. The heat medium from the heat exchanger 3 heats the thermoelectric element 1 of the second thermoelectric generator and is then sent to the exhaust heater heat exchanger 16 located on the outer surface of the exhaust stack 4 above it. An exhaust heater 15 is installed on the inner surface of the exhaust stack 4 corresponding to the exhaust heater heat exchanger 16, and the air inside the exhaust stack 4 is heated by the exhaust heater 15 using the heat from the exhaust heater heat exchanger 16. This heating promotes upward air flow, increasing the flow of incoming air and improving the cooling effect of the cooling fins. The heat medium from the heat exchanger 3 can be effectively used after heating the second thermoelectric generator.

[0036] In addition, a heating means for heating the inside of the exhaust pipe is arranged between the thermoelectric generator and the intake port in the vertical direction of the exhaust pipe 4. In this way, the air is heated before it is taken in, and the air sent to the compressor can be heated. By heating the air before compression, the temperature of the compressed air can be further increased.

[0037] In this embodiment, the same effects as those of the first embodiment can be obtained, and furthermore, power can be generated efficiently using a plurality of thermoelectric generators. Furthermore, energy loss is reduced throughout the entire system, and thermal energy can be used effectively. [Explanation of symbols]

[0038] 1...thermoelectric element, 2...cooling fin, 3...heat exchanger, 4...exhaust stack, 5...inlet air, 6...exhaust air 9...Compressor, 10...High-temperature compressed gas, 11...Expansion valve, 12...Compressed gas after cooling, 13...Low-temperature exhaust gas, 14...distribution damper, 15...exhaust air heater, 16...heat exchanger for exhaust air heater, 17... compression chamber, 20... piston, 21... cylinder, 22... drive mechanism, 23... intake check valve

Claims

1. A thermoelectric generator system including a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, the thermoelectric generator having a heat source for heating one surface of the thermoelectric element and an air-cooled cooling fin for cooling the other surface of the thermoelectric element; a compressor that compresses the exhaust air after cooling the cooling fins; a compression chamber that stores high-temperature, high-pressure gas compressed by the compressor and serves as the heat source; an expansion valve for reducing the pressure of the low-temperature, high-pressure gas from the compression chamber; A thermoelectric generator system configured to cool the cooling fins with low-temperature gas from the expansion valve.

2. 10. The thermoelectric generator system of claim 1, The thermoelectric generator system is characterized in that the compressor is a cylindrical compressor.

3. A thermoelectric generator system including a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, the thermoelectric generator having a heat source for heating one surface of the thermoelectric element and an air-cooled cooling fin for cooling the other surface of the thermoelectric element; an exhaust stack extending in the vertical direction and recovering the cooled air and discharging it upward; a cylinder-type compressor that takes in exhaust air from an upper portion of the exhaust stack and compresses the exhaust air after cooling the cooling fins; a compression chamber that stores the high-temperature, high-pressure gas compressed in the cylindrical compressor and serves as the heat source; an expansion valve for reducing the pressure of the low-temperature, high-pressure gas from the compression chamber; A thermoelectric generator system characterized in that the cooling fins are cooled by low-temperature gas from the expansion valve.

4. A thermoelectric generator system including a thermoelectric generator that generates electricity using a plate-shaped thermoelectric element, a first thermoelectric generator having a heat source for heating one side of the thermoelectric element and an air-cooled cooling fin for cooling the other side of the thermoelectric element; an exhaust stack extending in the vertical direction and recovering the cooled air and discharging it upward; a cylinder-type compressor that takes in exhaust air after cooling the cooling fins through an intake port at the top of the exhaust stack and compresses it; a compression chamber in which the high-temperature, high-pressure gas compressed by the cylindrical compressor is stored and used as the heat source for the first thermoelectric generator; an expansion valve for reducing the pressure of the low-temperature, high-pressure gas from the compression chamber; The cooling fins are cooled by the low-temperature gas from the expansion valve, A thermoelectric generator system characterized in that it further comprises a heating means for heating the inside of the exhaust stack, the heating means being arranged between the thermoelectric generator and the intake port in the vertical direction.

5. 5. The thermoelectric generator system of claim 4, a second thermoelectric generator provided below the heating means; the cooling fin for cooling one surface of the thermoelectric element of the second thermoelectric generator is disposed inside the exhaust stack, and a heat exchanger for heating the thermoelectric element is disposed outside the exhaust stack; A thermoelectric generator system, characterized in that the medium that has undergone heat exchange in the heat exchanger is used as a heat source for the heating means.

6. A power generation method for a thermoelectric generator system including a thermoelectric generator that generates power using a plate-shaped thermoelectric element, a power generation step of generating power using the thermoelectric generator having a heat source for heating one surface of the thermoelectric element and an air-cooled cooling fin for cooling the other surface of the thermoelectric element; a compression step of compressing the exhaust air after cooling the cooling fins by a cylinder type compressor; a heating step of heating one surface of the thermoelectric element by a compression chamber that stores high-temperature, high-pressure gas compressed by the cylindrical compressor; a discharging step of reducing the pressure of the low-temperature, high-pressure gas from the compression chamber; a cooling step of cooling the cooling fins with low-temperature gas from the exhaust step.

7. 7. The method for generating electricity using a thermoelectric generator system according to claim 6, a power generation method for a thermoelectric generator system, wherein the exhaust step is performed when the temperature of the compression chamber of the cylindrical compressor falls below a predetermined temperature.

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