Temperature difference power generation device combining phase change heat storage and radiation refrigeration

Abstract

The utility model discloses a thermoelectric power generation device and method combining phase change heat storage and radiation refrigeration, and belongs to the field of thermoelectric power generation. The device comprises a cold end, a thermoelectric generator, a hot end and a solar heat collection structure, two ends of the thermoelectric generator are respectively connected with the cold end and the hot end, the hot end is connected with the solar heat collection structure, the cold end comprises a refrigeration guide plate, and the top of the refrigeration guide plate is coated with a radiation refrigeration material layer. The utility model aims to solve the problems of low temperature gradient, low generating capacity and poor continuity in the existing thermoelectric power generation technology and radiation refrigeration thermoelectric power generation, and provides energy of a thermoelectric generator for a hot end by using clean solar energy, and ensures the long-time stability of the temperature of the hot end through the storage of a heat storage material. Meanwhile, the zero-energy-consumption radiation refrigeration technology is used for reducing the temperature of the cold end, a certain temperature difference is formed at night in cooperation with the heat storage material, and the temperature gradient is enlarged. Long-time high-temperature difference can be kept, 24-hour efficient continuous power generation is achieved, and the generating capacity is large.

Description

Technical Field

[0001] This utility model relates to a thermoelectric power generation device that combines phase change thermal storage and radiative cooling, belonging to the field of thermoelectric power generation. Background Technology

[0002] Electricity production is a crucial issue in contemporary societal development. Energy is a vital means of electricity production and a major source of carbon emissions. With rapid societal development, electricity demand has increased dramatically, exacerbating the energy crisis and worsening environmental pollution. Therefore, actively developing renewable energy sources to replace fossil fuels is of significant practical importance in addressing this challenge.

[0003] Currently, major new power generation methods include solar, wind, and nuclear power. While these provide clean energy, they also have drawbacks such as intermittent power generation, regional limitations, and complex equipment. Besides these, thermoelectric power generation (TEG), as a power generation method that requires no active energy input, has attracted widespread attention due to its low-carbon and environmentally friendly characteristics. TEG technology generates electricity solely using the temperature gradient between its hot and cold ends, thus offering advantages such as simple structure, small size, portability, and quiet operation. It can provide a new strategy for powering off-grid sensors and lighting equipment in remote areas. However, existing TEG technologies suffer from low temperature gradients and low power generation, making it impossible to achieve long-term, high-efficiency power generation.

[0004] Therefore, there is an urgent need to propose a thermoelectric power generation device that combines phase change thermal storage and radiative cooling to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to address the problems of low temperature gradient, low power generation, and poor continuity in existing thermoelectric power generation technologies, particularly in radiative cooling thermoelectric power generation. A brief overview of this invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit its scope.

[0006] The technical solution of this utility model:

[0007] A thermoelectric power generation device combining phase change thermal storage and radiative cooling: includes a cold end, a thermoelectric generator, a hot end, and a solar collector structure. The two ends of the thermoelectric generator are connected to the cold end and the hot end, respectively. The hot end is connected to the solar collector structure. The cold end includes a cooling guide plate, and the top of the cooling guide plate is coated with a radiative cooling material layer.

[0008] The hot end includes aluminum fins, a phase change material layer, an insulation layer, and a solar absorber. The solar absorber has a phase change material layer on top, and an insulation layer is wrapped around the outside of the phase change material layer. One side of the aluminum fins is connected to a thermoelectric generator, and the fin end on the other side of the aluminum fins is inserted into the phase change material layer. The solar absorber absorbs solar heat transferred from the solar collector structure.

[0009] Preferably, the solar thermal collection structure includes a greenhouse cavity, a solar concentrator, and a base plate. The base plate is provided at the bottom of the greenhouse cavity, and the solar concentrator is placed on the base plate inside the greenhouse cavity. A solar absorber is installed at the top of the greenhouse cavity, and the light absorbed by the solar concentrator is reflected onto the solar absorber.

[0010] Preferably, the solar absorber includes an aluminum plate and a black coating layer. The bottom of the aluminum plate is coated with the black coating layer, and the light absorbed by the solar concentrator is reflected onto the black coating. The top of the aluminum plate is tightly connected to the bottom of the aluminum fins.

[0011] Preferably, the greenhouse cavity is a transparent, hollow, conical cylinder.

[0012] Preferably, the cold end is connected to the thermoelectric generator via thermally conductive adhesive, and the cold end provides the cold end temperature to the thermoelectric generator; the top of the aluminum fin is connected to the thermoelectric generator via thermally conductive adhesive, and the hot end provides the hot end temperature to the thermoelectric generator.

[0013] Preferably, the base plate is a black heat-absorbing base plate.

[0014] Preferably, the greenhouse cavity is a transparent hollow conical cylinder formed by at least four transparent acrylic panels.

[0015] This utility model has the following beneficial effects:

[0016] 1. This invention utilizes clean solar energy to provide energy for a thermoelectric generator at the hot end, and stores this energy through thermal storage materials, ensuring the long-term stability of the hot end temperature. Simultaneously, it employs zero-energy radiative cooling technology to lower the cold end temperature, and at night, in conjunction with the thermal storage materials, creates a temperature difference, expanding the temperature gradient. This allows for maintaining a high temperature difference for an extended period, achieving efficient continuous power generation 24 hours a day with a large output.

[0017] 2. This utility model stores unused solar energy during the day when there is sufficient solar energy through a phase change material layer, and releases it when the solar energy is weak, which can continuously extend the hot end temperature of the thermoelectric generator, thereby improving the unit power generation efficiency of the thermoelectric generator.

[0018] 3. This utility model uses a cooling guide plate coated with a radiation cooling material layer as the cold end. It releases its own heat through radiation heat exchange with the external space, thereby achieving sub-environmental cooling. It can minimize the energy absorption of the device without consuming energy and achieve cooling of the cold end of the thermoelectric generator.

[0019] 4. This utility model can effectively increase the temperature of the hot and cold ends of the thermoelectric generator and extend the high-efficiency power generation time, providing 24-hour all-weather power generation. It solves the problem of low and discontinuous power generation of existing thermoelectric generators, and can supply power to small equipment in remote areas, with broad application prospects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a thermoelectric power generation device that combines phase change thermal storage and radiative cooling.

[0021] Figure 2 This is a graph showing the temperature and temperature difference changes of the hot and cold ends of the thermoelectric generator provided in the embodiment.

[0022] Figure 3 This is a graph showing the open-circuit voltage and output power variation of the thermoelectric generator provided in the embodiment.

[0023] In the diagram: 1-Cold end, 2-Thermoelectric generator, 3-Hot end, 4-Solar heat collection structure, 31-Aluminum fins, 32-Phase change material layer, 33-Insulation layer, 34-Solar absorber, 41-Greenhouse cavity, 42-Solar concentrator, 43-Base plate. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the present utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present utility model.

[0025] The connections mentioned in this utility model are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0026] Example: Combining Figures 1-3This embodiment describes a thermoelectric generator combining phase change thermal storage and radiative cooling, comprising a cold end 1, a thermoelectric generator 2, a hot end 3, and a solar collector structure 4. The two ends of the thermoelectric generator 2 are connected to the cold end 1 and the hot end 3, respectively. The hot end 3 is connected to the solar collector structure 4. The cold end 1 includes a cooling guide plate, and the top of the cooling guide plate is coated with a radiative cooling material layer.

[0027] The hot end 3 includes aluminum fins 31, a phase change material layer 32, a heat insulation layer 33, and a solar absorber 34. The solar absorber 34 is provided with a phase change material layer 32 on top, and the phase change material layer 32 is wrapped with a heat insulation layer 33. One side of the aluminum fins 31 is connected to the thermoelectric generator 2, and the fin end on the other side of the aluminum fins 31 is inserted into the phase change material layer 32. The solar absorber 34 absorbs solar heat transferred from the solar collector structure 4.

[0028] The aluminum fin 31 is a custom-made aluminum product. The heat-conducting fins at the bottom of the aluminum fin 31 extend into the phase change material layer 32. The number of heat-conducting fins should be no less than 7. The high thermal conductivity of the aluminum fin 31 can transfer the heat from the hot end 3 to the hot end of the thermoelectric generator 2 as quickly as possible.

[0029] The phase change material layer 32 is one of the phase change materials such as paraffin wax, lauric acid, polyethylene glycol monomethyl ether methacrylate, and neopentyl glycol. The phase change temperature is between 30-50℃. The phase change material layer 32 mainly absorbs excess solar heat energy and melts it to store thermal energy during the time when the solar irradiance is high at noon, and solidifies and releases thermal energy during the time when the sunlight is weak, so as to continue to maintain the hot end temperature of the thermoelectric generator 2 and realize the purpose of converting visible light or ultraviolet light to generate electrical energy.

[0030] The insulation layer 33 is composed of at least one or more of the following insulation materials: aluminum foil insulation cotton, polystyrene foam board, polyurethane foam insulation material, and glass fiber insulation cotton. The thickness is maintained at 5 cm or more to minimize heat loss from the phase change material layer 32. The solar absorber 34 is composed of an aluminum plate coated with black paint. Its upper end is tightly connected to heat-conducting aluminum fins 31, which can quickly conduct the energy absorbed by the solar collector structure 4.

[0031] The solar thermal collector structure 4 includes a greenhouse cavity 41, a solar concentrator 42, and a base plate 43. The base plate 43 is located at the bottom of the greenhouse cavity 41, and the solar concentrator 42 is placed on the base plate 43 inside the greenhouse cavity 41. A solar absorber 34 is installed on the top of the greenhouse cavity 41, and the light absorbed by the solar concentrator 42 is reflected onto the solar absorber 34. The base plate 43 is a black heat-absorbing base plate.

[0032] The thermoelectric generator 2 is a commercial thermoelectric generator, model SP1848-27145. The cold end 1 is connected to the thermoelectric generator 2 via thermally conductive adhesive, providing the cold end temperature for the thermoelectric generator 2. The top of the aluminum fin 31 is connected to the thermoelectric generator 2 via thermally conductive adhesive, and the hot end 3 provides the hot end temperature for the thermoelectric generator 2. The thermoelectric generator 2 has a square thermoelectric element with a side length of 4cm, composed of 128 pairs of P-type semiconductors and N-type semiconductors connected in series with internal resistance. It can convert temperature difference into electrical energy through the Seebeck effect.

[0033] The solar absorber 34 includes an aluminum plate and a black coating layer. The bottom of the aluminum plate is coated with a black coating layer. The light absorbed by the solar concentrator 42 is reflected onto the black coating. The top of the aluminum plate is tightly connected to the bottom of the aluminum fins 31.

[0034] The greenhouse cavity 41 is a transparent hollow conical cylinder. The greenhouse cavity 41 is a transparent hollow conical cylinder formed by at least four transparent acrylic panels, with a height of 40cm, matching the focal length of the dish-type solar concentrator 42. Its upper end is connected to the hot end 3. The acrylic panels have high transmittance in the solar light band and low transmittance in the near-infrared band, allowing more sunlight to pass through and reducing infrared energy emission. Therefore, the internal temperature can be higher than the ambient temperature, providing a higher temperature environment for the hot end of the thermoelectric generator 2.

[0035] The solar concentrator 42 is a mirror reflector that can concentrate sunlight within an area into a single point, thereby increasing the solar irradiance per unit area and greatly increasing the temperature of the hot end 3. The base plate 43 is a black heat-absorbing base plate, such as a black foam board, which supports the greenhouse cavity 41, the cold end 1, the thermoelectric generator 2, and the hot end 3, and can absorb ambient heat to maintain the temperature inside the greenhouse cavity 41.

[0036] The radiation-cooling material layer includes a substrate medium and a radiation-cooling coating mixed with the substrate medium, wherein the radiation-cooling coating includes metal particles and the substrate medium.

[0037] The metal particles include visible light reflective particles, near-infrared reflective particles, and atmospheric window band emission particles.

[0038] The visible light reflective particles include, but are not limited to, TiO2, CaCO3, BaSO4, etc.

[0039] The near-infrared reflective particles include, but are not limited to, Al2O3, SiO2, etc.

[0040] The atmospheric window band emitted particles include, but are not limited to, SiC, Si3N4, etc.

[0041] The metal particles possess the desired superior optical properties, enabling complementarity across different wavelengths. All particle sizes span two orders of magnitude.

[0042] The substrate medium includes a film-forming substrate, a film-forming aid, a dispersant, an antifoaming agent, a thickener, a leveling agent, and deionized water.

[0043] The film-forming substrate is acrylic resin; the film-forming aid is one or a combination of several of propylene glycol phenyl ether, ethylene glycol butyl ether, benzyl alcohol, or dodecyl alcohol ester; the dispersant is one or a combination of several of sodium polycarboxylate, sulfate salt, aminopropylamine dioleate, fatty acid ethylene oxide adduct, phosphate salt type polymer, or oleoamino oleate; the defoamer is one or a combination of several of tributyl phosphate, polyether defoamer, or silicone defoamer; the thickener is one or a combination of several of carboxymethyl cellulose, methyl cellulose, or hydroxypropyl methyl cellulose; the leveling agent is one or a combination of several of acrylate homopolymer or copolymer, acetate butyrate, silicone, methylphenyl polysiloxane, organo-modified siloxane, or acrylic acid. The materials are mixed and stirred in a specific ratio to obtain a radiative cooling material layer. The radiative cooling material layer is uniformly coated onto a cooling guide plate to obtain cold end 1.

[0044] It also includes a thermoelectric power generation method based on a thermoelectric power generation device combining phase change thermal storage and radiative cooling as described in this embodiment, comprising:

[0045] Sunlight shines on the cold end 1, and the radiative cooling material layer of the cold end 1 absorbs the sunlight and cools down at the same time, providing the cold end temperature for the thermoelectric generator 2. At the same time, sunlight also passes through the greenhouse cavity 41 and shines on the solar concentrator 42. The solar concentrator 42 reflects the absorbed light onto the solar absorber 34, which generates heat. A portion of the heat generated by the solar absorber 34 is directly transferred to the thermoelectric generator 2 through the aluminum fins 31, and the other portion of the heat generated by the solar absorber 34 is stored in the phase change material layer 32. The phase change material layer 32 is continuously transferred to the thermoelectric generator 2 through the aluminum fins 31, together providing the hot end temperature for the thermoelectric generator 2.

[0046] To verify the all-day power generation capability of this embodiment, an outdoor experiment was conducted in Weihai, Shandong (37°30′45″N, 122°06′55″E). The thermoelectric power generation device combining phase change thermal storage and radiative cooling of this embodiment was placed in an open area with unobstructed views, and the weather was sunny and the temperature was suitable during the experiment. The experimental temperature and output voltage were recorded using a paperless recorder, and environmental factors were recorded using a small weather station.

[0047] Outdoor experimental results such as Figure 2 , 3As shown, due to the heat storage function of the phase change material layer 32, the thermoelectric power generation device combining phase change heat storage and radiative cooling in this embodiment can maintain a large temperature difference for a relatively long time. The maximum temperature difference between the hot and cold ends of the thermoelectric generator 2 can reach 18.5℃. Simultaneously, the thermoelectric power generation method implemented by the thermoelectric power generation device combining phase change heat storage and radiative cooling in this embodiment ensures that the temperature difference remains above 0℃ throughout the day, guaranteeing the device's continuous power generation. The maximum output voltage can reach 501mV, and the output power is 12.2W / m².

[0048] The thermoelectric power generation method described in this embodiment, which combines phase change thermal storage and radiative cooling, ensures that the cold end temperature of the thermoelectric generator 2 remains lower than the hot end temperature throughout the day, achieving continuous power generation for 24 hours. Furthermore, the phase change material layer 32 stores any unused solar thermal energy, significantly improving power generation efficiency. This power generation device solves the problems of low power output and discontinuous power generation in traditional thermoelectric power generation systems, providing a new strategy for powering micro-devices in remote areas.

[0049] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, this utility model will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by this utility model.

[0050] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A thermoelectric power generation device combining phase change thermal storage and radiative cooling, characterized in that: It includes a cold end (1), a thermoelectric generator (2), a hot end (3) and a solar collector structure (4). The two ends of the thermoelectric generator (2) are connected to the cold end (1) and the hot end (3) respectively. The hot end (3) is connected to the solar collector structure (4). The cold end (1) includes a cooling guide plate, and the top of the cooling guide plate is coated with a radiation cooling material layer. The hot end (3) includes aluminum fins (31), a phase change material layer (32), a heat insulation layer (33), and a solar absorber (34). The solar absorber (34) has a phase change material layer (32) on top and a heat insulation layer (33) wrapped around the outside of the phase change material layer (32). One side of the aluminum fins (31) is connected to the thermoelectric generator (2), and the fin end on the other side of the aluminum fins (31) is inserted into the phase change material layer (32). The solar absorber (34) absorbs the solar heat transferred from the solar heat collection structure (4).

2. The thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 1, characterized in that: The solar thermal collection structure (4) includes a greenhouse cavity (41), a solar concentrator (42), and a base plate (43). The bottom of the greenhouse cavity (41) is provided with a base plate (43). The solar concentrator (42) is placed on the base plate (43) inside the greenhouse cavity (41). A solar absorber (34) is installed on the top of the greenhouse cavity (41). The light absorbed by the solar concentrator (42) is reflected onto the solar absorber (34).

3. A thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 2, characterized in that: The solar absorber (34) includes an aluminum plate and a black coating layer. The bottom of the aluminum plate is coated with a black coating layer. The light absorbed by the solar concentrator (42) is reflected onto the black coating. The top of the aluminum plate is tightly connected to the bottom of the aluminum fins (31).

4. A thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 3, characterized in that: The greenhouse cavity (41) is a transparent hollow conical cylinder.

5. A thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 4, characterized in that: The cold end (1) is connected to the thermoelectric generator (2) through thermally conductive adhesive, and the cold end (1) provides the cold end temperature to the thermoelectric generator (2). The top of the aluminum fin (31) is connected to the thermoelectric generator (2) through thermally conductive adhesive, and the hot end (3) provides the hot end temperature to the thermoelectric generator (2).

6. A thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 5, characterized in that: The base plate (43) is a black heat-absorbing base plate.

7. A thermoelectric power generation device combining phase change thermal storage and radiative cooling according to claim 6, characterized in that: The greenhouse cavity (41) is a transparent hollow conical cylinder formed by at least four transparent acrylic plates.

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