A dual energy storage continuous temperature difference power generation device based on photo-thermal conversion and radiation refrigeration

Abstract

This invention discloses a dual-energy storage continuous thermoelectric generator based on photothermal conversion and radiative cooling, belonging to the field of renewable energy power generation technology. It solves the technical defects of existing thermoelectric generators that lack energy storage structures and cannot achieve continuous day and night power generation. The dual-energy storage continuous thermoelectric generator includes a thermoelectric generator plate, a heat collection and storage section, and a cooling and storage section. The heat collection and storage section is located below the thermoelectric generator plate, and the cooling and storage section is located above it. The heat collection and storage section includes a photothermal conversion phase change material that converts solar radiation into heat energy and stores the heat energy. The cooling and storage section includes a radiative cooling and storage material that generates and stores cold energy. By independently storing energy at both ends of the thermoelectric generator plate through the heat collection and storage section and the cooling and storage section, a continuous temperature difference is maintained between the two ends of the thermoelectric generator plate, achieving continuous power generation throughout the day.

Description

Technical Field

[0001] This invention relates to the field of renewable energy power generation technology, and in particular to a dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling, which can combine solar thermal utilization, radiative cooling technology and energy storage technology. Background Technology

[0002] Semiconductor thermoelectric power generation technology is a green power generation technology that directly converts heat energy into electrical energy based on the Seebeck effect. It has the advantages of simple structure, no moving parts, no noise, no pollutant emissions, convenient maintenance and long service life, and has broad application prospects in the field of renewable energy utilization.

[0003] Traditional thermoelectric power generation technology relies mainly on non-renewable or high-energy-consuming methods such as fossil fuel combustion, industrial waste heat, and artificial heating. This not only results in high energy consumption and high operating costs but may also be accompanied by pollutant emissions, limiting its large-scale application in the field of sustainable energy and contradicting the current development concept of energy conservation and environmental protection.

[0004] To address the aforementioned issues, utilizing clean and pollution-free solar energy as the energy source for thermoelectric power generation, and providing a stable temperature difference for the thermoelectric generator, has garnered increasing attention (as disclosed in CN102355168B and CN110635717B). This technology combines solar energy absorption with semiconductor thermoelectric power generation technology, using sunlight to heat the hot end of the thermoelectric generator, driving the thermoelectric power generation device to output electricity. Compared to traditional solar photovoltaic and solar thermal power generation technologies, this type of device not only has lower costs and stronger environmental adaptability, but also boasts advantages such as compact structure, low maintenance costs, and long service life, while avoiding secondary pollution to the environment.

[0005] However, existing solar-driven thermoelectric power generation technology still faces core technological bottlenecks: solar energy is discontinuous and unstable, and is significantly affected by natural factors such as day-night cycles and weather changes, resulting in unstable heat supply at the hot end of the thermoelectric generator and an inability to guarantee stable power output.

[0006] Meanwhile, during operation, the temperature of the thermoelectric generator's cold end rises synchronously with the temperature of its hot end due to heat conduction. If the low temperature of the cold end cannot be effectively maintained, the thermoelectric power generation efficiency will be significantly reduced. Currently, commonly used cold end cooling methods in the industry mainly include natural air convection, forced air convection, and forced liquid convection. Among these, natural air convection has limited cooling effect and is difficult to meet the cold end temperature requirements for high-efficiency power generation; while forced convection requires auxiliary equipment such as fans and water pumps, which consume additional electrical energy during operation, increasing system energy consumption and reducing the net power generation efficiency of the entire power generation device.

[0007] Sky radiation cooling technology, a zero-energy green cooling technology, works by utilizing the atmospheric infrared transparency window in the 8-13 μm band to radiate heat from an object's surface into deep, cold outer space in the form of infrared electromagnetic waves. This passively cools the object without consuming any additional energy, effectively solving the energy consumption problem of cooling the cold end of thermoelectric generators. Therefore, introducing sky radiation cooling technology into thermoelectric generators can achieve autonomous reduction of the cold end temperature, further improving power generation efficiency.

[0008] However, similar to solar energy, the cooling capacity of sky radiation cooling technology also exhibits significant diurnal variations: during the day, due to the influence of direct solar radiation, the surface of the cooling device absorbs some solar radiation, resulting in lower net radiation cooling power and poor cooling effect; while at night, without solar radiation interference, the cooling capacity is significantly enhanced and the cooling effect is superior. Therefore, simply combining sky radiation cooling technology with thermoelectric power generation technology is still insufficient to achieve stable maintenance of the cold end temperature around the clock. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to provide a dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling that can solve the above problems. It can utilize natural heat sources and cold sources to maintain a stable temperature difference between day and night for the thermoelectric power generation unit, thereby achieving continuous and stable power output throughout the day.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows: A dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling includes a thermoelectric generator, a heat collection and storage section, and a cooling and storage section. The heat collection and storage section is located below the thermoelectric generator, and the cooling and storage section is located above it. The heat collection and storage section includes a photothermal conversion phase change material that converts solar radiation into heat energy and stores the heat energy. The cooling and storage section includes a radiative cooling and storage material that generates and stores cold energy. By independently storing energy at both ends of the thermoelectric generator through the heat collection and storage section and the cooling and storage section, a continuous temperature difference is maintained between the two ends of the thermoelectric generator, achieving continuous power generation throughout the day. This dual-end independent energy storage design overcomes the technical shortcomings of existing thermoelectric power generation devices that lack energy storage structures and cannot achieve continuous day and night power generation, enabling the thermoelectric generator to maintain a stable temperature difference throughout the day and night, thus achieving continuous power generation throughout the day.

[0011] Optionally, the photothermal conversion phase change material is prepared by the following method: heating and melting the phase change material raw material, adding expanded graphite and photothermal conversion reinforcing material, stirring and mixing evenly, and cooling to room temperature to obtain the photothermal conversion phase change material; the phase change material raw material is an organic phase change material or an inorganic phase change material; the photothermal conversion reinforcing material is one of graphene, carbon nanotubes, and reduced graphene oxide.

[0012] Optionally, the mass fraction of the phase change material raw material is 60%-90%, the mass fraction of expanded graphite is 5%-20%, and the mass fraction of photothermal conversion reinforcing material is 0.1%-2%; the sum of the mass fractions of each component is 100%.

[0013] Optionally, the phase change temperature of the photothermal conversion phase change material is 50-80 ℃, the latent heat of phase change is ≥150 J / g, and the absorptivity in the solar light band is ≥85%. The photothermal conversion phase change material can efficiently realize the photothermal conversion of solar radiation and stably store the converted heat energy, providing a stable heat source for the hot end of the thermoelectric generator.

[0014] Optionally, the radiation cooling and cold storage material is prepared by the following method: dissolving the polymer matrix in a solvent, then adding phase change microcapsules and mixing evenly, and obtaining the radiation cooling and cold storage material after the solvent evaporates.

[0015] Optionally, the phase change microcapsules account for 30%-60% of the mass of the radiative cooling and cold storage material, the polymer matrix is ​​one of PDMS, PMMA, PVDF, PVA, and PS, and the solvent is one of acetone, ethyl acetate, cyclohexane, toluene, and DMF.

[0016] Optionally, the radiative cooling and cold storage material has a reflectivity of ≥85% in the solar radiation band, an emissivity of ≥90% in the atmospheric window band, a phase change temperature of 10-30 ℃, and a latent heat of phase change of ≥60 J / g. The radiative cooling and cold storage material possesses high reflectivity in the visible-near infrared light, high emissivity in the 8-13 μm atmospheric window, and phase change cold storage function, enabling zero-energy radiative cooling and cold energy storage, continuously providing a stable cold source for the cold end of the thermoelectric generator.

[0017] Optionally, the heat collection and storage section further includes an insulation layer, and the photothermal conversion phase change material is filled within the insulation layer. The insulation layer is used to reduce heat loss in the heat collection and storage section and ensure the stability of the heat source at the hot end.

[0018] Optionally, the refrigeration and cold storage section further includes a transparent protective layer that covers the radiative refrigeration and cold storage material. The transparent protective layer is used to reduce non-radiative heat transfer between the radiative refrigeration and cold storage material and the environment.

[0019] Optionally, the thermoelectric generator is a Bi2Te3-based thermoelectric generator, and the contact interfaces between the thermoelectric generator and the heat collection and storage section and the cooling and cold storage section are coated with thermally conductive silicone grease. The thermally conductive silicone grease can effectively reduce contact thermal resistance, improve the efficiency of heat transfer at the hot end and cold transfer at the cold end, ensure a stable and sufficient temperature difference between the two ends of the thermoelectric generator, and guarantee power generation efficiency.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention adopts a dual-end independent energy storage design, which combines the heat storage function of photothermal conversion phase change material with the cold storage function of radiation refrigeration material, effectively solving the problem of unstable power output and inability to achieve continuous day and night power generation caused by the lack of energy storage structure in existing thermoelectric power generation equipment.

[0021] 2. In this invention, the photothermal conversion phase change material converts solar radiation into heat energy and stores it in the form of latent heat, providing a continuous and stable heat source for the hot end of the thermoelectric generator; the cold end of the thermoelectric generator faces the sky and is in contact with the radiative cooling storage material to obtain the cooling capacity generated by radiative cooling, and the phase change microcapsules embedded in the radiative cooling body serve as a cooling storage medium, which can maintain the low temperature of the cold end when the net radiative cooling power is low during the day, ensuring that the two ends of the thermoelectric generator always maintain a stable temperature difference, and realizing continuous power generation around the clock.

[0022] 3. The entire device relies on two natural energy sources: solar energy and sky radiation cooling. It requires no additional energy consumption, achieving zero-energy power generation. It has a reasonable structure and strong practicality. At the same time, by optimizing the material ratio, expanding the range of material selection, and improving the structural design, the efficiency of heat energy conversion, cooling, and power generation is further improved, ensuring the stability and continuity of power output. Attached Figure Description

[0023] Figure 1 A schematic diagram of the structure of a dual-energy storage continuous thermoelectric generator based on photothermal conversion and radiative cooling according to an embodiment of the present invention is shown.

[0024] Explanation of reference numerals in the attached diagram: 1-Thermoelectric generator; 2-Heat collection and storage section; 3-Refrigeration and cold storage section; 4-Insulation layer; 5-Transparent protective layer. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] like Figure 1 As shown, the dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling provided by the present invention includes a thermoelectric generator 1, a heat collection and storage section 2, and a cooling and cold storage section 3, wherein the heat collection and storage section 2 is located below the thermoelectric generator 1, and the cooling and cold storage section 3 is located above the thermoelectric generator 1. Preferably, the thermoelectric generator 1 is a Bi2Te3-based thermoelectric generator. More preferably, the contact interfaces between the thermoelectric generator 1 and the heat collection and storage section 2 and the cooling and cold storage section 3 are all coated with thermally conductive silicone grease.

[0029] The thermal collection and storage section 2 includes a photothermal conversion phase change material, which converts solar radiation into heat energy and stores it. The cooling and cold storage section 3 includes a radiative cooling and cold storage material, which generates and stores cold energy. Through the dual-end independent energy storage design of the thermal collection and storage section 2 and the cooling and cold storage section 3, the thermoelectric generator 1 maintains a stable temperature difference throughout the day and night, achieving continuous power generation.

[0030] The photothermal conversion phase change material of the heat collection and storage section 2 is prepared by the following method: the phase change material raw material is heated and melted, expanded graphite and photothermal conversion reinforcing material are added, stirred and mixed evenly, and cooled to room temperature to obtain the photothermal conversion phase change material. Preferably, the phase change material raw material is an organic phase change material or an inorganic phase change material. Preferably, the organic phase change material is paraffin or polyethylene glycol. Preferably, the inorganic phase change material is sodium acetate trihydrate or barium hydroxide octahydrate. The photothermal conversion reinforcing material is one of graphene, carbon nanotubes, and reduced graphene oxide. Preferably, the mass fraction of the phase change material raw material is 60%-90%, the mass fraction of expanded graphite is 5%-20%, and the mass fraction of the photothermal conversion reinforcing material is 0.1%-2%; the sum of the mass fractions of all components is 100%. The phase change temperature of the photothermal conversion phase change material is 50-80 ℃, the latent heat of phase change is ≥150 J / g, and the solar light absorption rate is ≥85%.

[0031] The radiation-induced cooling and cold storage material in section 3 is prepared by the following method: a polymer matrix is ​​dissolved in a solvent, then phase change microcapsules are added and mixed evenly. After the solvent evaporates, the radiation-induced cooling and cold storage material is obtained. Preferably, the phase change microcapsules account for 30%-60% of the mass of the radiation-induced cooling and cold storage material. The polymer matrix is ​​one of PDMS, PMMA, PVDF, PVA, and PS. The solvent is one of acetone, ethyl acetate, cyclohexane, toluene, and DMF.

[0032] Phase change microcapsules can be made using existing phase change microcapsules. For example, a phase change microcapsule includes a phase change core material and a shell material, wherein the core material is a paraffin-based low-temperature phase change material (such as n-hexadecane, n-octadecane, etc.), and the shell material is one of SiO2, CaCO3, and TiO2. The radiation-cooled cold storage material has a reflectivity ≥85% in the solar radiation band, an emissivity ≥90% in the atmospheric window band, a phase change temperature of 10-30 ℃, and a latent heat of phase change ≥60 J / g.

[0033] The heat collection and storage section 2 also includes an insulation layer 4. Photothermal conversion phase change material is filled within the insulation layer 4 to reduce heat loss in the heat collection and storage section. The cooling and cold storage section 3 also includes a transparent protective layer 5. The transparent protective layer 5 covers the radiative cooling and cold storage material to reduce non-radiative heat transfer between the radiative cooling and cold storage material and the environment.

[0034] The working process of the dual-energy storage continuous thermoelectric generator based on photothermal conversion and radiative cooling provided by this invention is as follows: The photothermal conversion phase change material of the heat collection and storage section 2 absorbs solar radiation, converts it into heat energy, and stores it inside the material in the form of latent heat; the radiative cooling and storage material of the cooling and storage section 3 utilizes an 8-13 μm atmospheric infrared transparent window to radiate the cold energy into deep cold outer space in the form of infrared electromagnetic waves, achieving passive cooling and storing the cold energy. At night and during cloudy weather with no or weak solar radiation, the heat collection and storage section 2 releases the stored heat energy; during the day when solar radiation is strong and the radiative cooling performance is poor, the cooling and storage section 3 releases the stored cold energy. The heat collection and storage section 2 and the cooling and storage section 3 work together to maintain a continuous temperature difference between the two ends of the thermoelectric generator 1, ensuring continuous power generation.

[0035] Note: In the following examples and comparative examples, the performance testing methods are uniformly as follows: Absorbance / reflectance in the solar radiation band was measured using a UV-Vis-NIR spectrophotometer (wavelength range 200-2500 nm); emissivity in the atmospheric window band was measured using a Fourier transform infrared spectrometer (wavelength range 8-13 μm); phase transition temperature and latent heat of phase transition were measured using a differential scanning calorimeter (DSC); power generation performance was tested under outdoor natural conditions (sunny daytime radiation intensity 800-1000 W / m²). 2 (Ambient temperature 15-25 ℃), tested 24-hour continuous power generation and temperature difference stability.

[0036] Example 1 This embodiment provides a dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling. The specific structure, material preparation, and performance are as follows: 1. Thermoelectric generator: Bi2Te3-based thermoelectric generator is used, and the contact interface between the thermoelectric generator and the heat collection and storage part 2 and the cooling and cold storage part 3 is coated with thermal grease.

[0037] 2. Preparation and properties of photothermal conversion phase change materials: Preparation method: The phase change material raw material (paraffin wax, melting point 58-60 ℃) was heated to 80 ℃ and melted. Expanded graphite (10% by mass) and photothermal conversion enhancement material (graphene, 0.5% by mass) were added. The mixture was stirred for 30 min using a mechanical stirrer (100 r / min) until homogeneous. After mixing, it was naturally cooled to room temperature to obtain the photothermal conversion phase change material. The paraffin wax had a mass fraction of 89.5%. The addition of expanded graphite improved the structural stability of the material and prevented leakage during the phase change process, while graphene further enhanced the photothermal absorption capacity.

[0038] Performance data: Phase change temperature 58 ℃, latent heat of phase change 177 J / g, solar radiation absorptivity 88%.

[0039] 3. Preparation and properties of radiation refrigeration and cold storage materials: Preparation method: The polymer matrix (PDMS) is dissolved in a solvent (acetone) (the amount of solvent is 3 times the mass of PDMS). After stirring until completely dissolved, phase change microcapsules (40% by mass) are added and stirred for another 20 min to mix evenly. The mixture is then placed in a fume hood and the solvent is allowed to evaporate naturally at room temperature to obtain the radiation cooling and cold storage material. The core material of the phase change microcapsules is n-octadecane (a paraffin-based low-temperature phase change material), and the shell material is SiO2.

[0040] Performance data: Phase transition temperature 28 ℃, latent heat of phase transition 68 J / g, reflectivity in solar band 89%, emissivity in atmospheric window band 92%.

[0041] 4. Auxiliary structure: The heat collection and storage section 2 is provided with an insulation layer 4, and the photothermal conversion phase change material is filled inside the insulation layer 4; the refrigeration and cold storage section 3 is provided with a transparent protective layer 5. Preferably, the transparent protective layer 5 is a low-density polyethylene film (thickness 0.1-0.2 mm), covering the radiative refrigeration and cold storage material.

[0042] 5. Power generation performance test results: 24-hour continuous power generation, with an average daily power output of approximately 0.6 mW / cm². 2 The average nighttime power generation is approximately 0.25 mW / cm². 2 The daytime temperature difference between the two ends of the thermoelectric generator is 18-22 degrees Celsius. C, the temperature difference between day and night is 10-14 degrees Celsius. C, the average daily temperature difference is approximately 16. C. There is no interruption in power generation, and the power generation process is stable.

[0043] Example 2 This embodiment has the same overall structure as Embodiment 1. The core difference lies in the material selection and some parameters of the photothermal conversion phase change material and the radiation cooling and cold storage material, as detailed below: 1. Preparation and properties of photothermal conversion phase change materials: Preparation method: The phase change material raw material (sodium acetate trihydrate, melting point about 58 ℃) was heated to 80 ℃ to melt, and expanded graphite (mass fraction 15%) and photothermal conversion enhancement material (carbon nanotubes, mass fraction 1.0%) were added. The mixture was stirred for 40 min with a mechanical stirrer (speed 100 r / min). After mixing evenly, the mixture was naturally cooled to room temperature to obtain the photothermal conversion phase change material; wherein, the mass fraction of sodium acetate trihydrate was 84.0%.

[0044] Performance data: Phase change temperature 58.5 ℃, latent heat of phase change 210 J / g, solar radiation absorption rate 90%.

[0045] 2. Preparation and properties of radiation refrigeration and cold storage materials: Preparation method: The polymer matrix (PMMA) is dissolved in a solvent (ethyl acetate) (the amount of solvent is 3 times the mass of PMMA). After stirring until completely dissolved, phase change microcapsules (50% by mass) are added and stirred for another 25 min to mix evenly. The mixture is then placed in a fume hood and the solvent is evaporated at a constant temperature of 60 °C to obtain the radiation cooling and cold storage material. The core material of the phase change microcapsules is n-hexadecane (a paraffin-based low-temperature phase change material), and the shell material is CaCO3.

[0046] Performance data: Phase transition temperature 18 ℃, latent heat of phase transition 85 J / g, reflectivity in solar band 91%, emissivity in atmospheric window band 93%.

[0047] 3. Auxiliary structure: Consistent with Example 1, the transparent protective layer 5 of the refrigeration and cold storage section 3 is made of low-density polyethylene film (thickness 0.1-0.2 mm).

[0048] 4. Power generation performance test results: 24-hour continuous power generation, with an average daily power output of approximately 1.1 mW / cm². 2 The average nighttime power generation is approximately 0.45 mW / cm². 2 The daytime temperature difference between the two ends of the thermoelectric generator is 22-26 degrees Celsius. C, the temperature difference between day and night is 12-18 degrees Celsius. C, the average daily temperature difference is approximately 20°C. C has a high power generation output capacity.

[0049] Example 3 This embodiment has the same overall structure as Embodiments 1 and 2, with the key difference being the photothermal conversion enhancement material, polymer matrix, and solvent. This further verifies the flexibility of material selection in this invention, as detailed below: 1. Preparation and properties of photothermal conversion phase change materials: Preparation method: The phase change material raw material (PEG-10000, 60-62 ℃) was heated to 80 ℃ and melted. Expanded graphite (12% by mass) and photothermal conversion enhancement material (reduced graphene oxide, 0.8% by mass) were added. The mixture was stirred for 35 min with a mechanical stirrer (100 r / min). After mixing evenly, the mixture was naturally cooled to room temperature to obtain the photothermal conversion phase change material. The mass fraction of PEG-10000 was 87.2%.

[0050] Performance data: Phase change temperature 61 ℃, latent heat of phase change 150 J / g, solar radiation absorptivity 87%.

[0051] 2. Preparation and properties of radiation refrigeration and cold storage materials: Preparation method: The polymer matrix (PVDF) is dissolved in a solvent (DMF) (the amount of solvent is 7 times the mass of PVDF). After stirring until completely dissolved, phase change microcapsules (35% by mass) are added and stirred for another 30 minutes to mix evenly. The mixture is then placed in a fume hood and the solvent is evaporated at a constant temperature of 40 °C to obtain the radiation cooling and cold storage material. The core material of the phase change microcapsules is n-hexadecane and the shell material is TiO2.

[0052] Performance data: Phase transition temperature 18 ℃, latent heat of phase transition 60 J / g, reflectivity in solar band 88%, emissivity in atmospheric window band 91%.

[0053] 3. Auxiliary structure: Consistent with Example 1, the transparent protective layer 5 of the refrigeration and cold storage section 3 is made of low-density polyethylene film (thickness 0.1-0.2 mm).

[0054] 4. Power generation performance test results: 24-hour continuous power generation, with an average daily power output of approximately 0.85 mW / cm². 2 The average nighttime power generation is approximately 0.50 mW / cm². 2 The daytime temperature difference between the two ends of the thermoelectric generator is 20-24 degrees Celsius. C, the temperature difference between day and night is 14-16 degrees Celsius. C, the average daily temperature difference is approximately 19. C. The temperature fluctuation at night is relatively small, resulting in good power generation stability and meeting the demand for continuous power generation throughout the day.

[0055] Comparative Example 1 This comparative example is an existing conventional thermoelectric generator, which does not have an energy storage structure and does not use the photothermal conversion phase change material and radiation refrigeration storage material of the present invention, as detailed below: 1. Structure: Includes a Bi2Te3-based thermoelectric generator, with a conventional solar absorber (without phase change thermal storage function) below, a conventional radiative cooling panel (without phase change cold storage capacity) above, and a transparent protective layer (consistent with the embodiment, using low-density polyethylene film with a thickness of 0.1-0.2 mm).

[0056] 2. Materials and properties: The solar absorption panel has a solar light absorption rate of 90% and no heat storage capacity; the radiative cooling panel has a solar light reflectance of 86% and an atmospheric window emissivity of 90%.

[0057] 3. Power generation performance test results: Stable power generation is possible during the day when there is solar radiation, with an average daytime power generation of approximately 1.2 mW / cm². 2 The daytime temperature difference is 20-28 degrees Celsius. C; At night, there is no solar radiation, and the solar heat absorption portion has no phase change heat storage capacity, so it cannot provide a continuous heat source. Although radiative cooling can still maintain a certain temperature difference (3-6 degrees Celsius at night). C), but lower than the effective operating temperature difference of Bi2Te3-based thermoelectric generators (approximately 10). (C) It cannot generate effective electrical energy; the power generation interruption time at night is about 12 hours, and it is impossible to achieve continuous power generation throughout the day.

[0058] Comparative Example 2 This comparative example only features a single thermal storage structure, without a cold storage structure, and no photothermal conversion enhancement material was used in the preparation of the hot-end phase change material, as detailed below: 1. Structure: Includes a Bi2Te3-based thermoelectric generator, a heat storage section below (without photothermal conversion enhancement material), a conventional radiative cooling plate above (without phase change cold storage function), an insulation layer, and a transparent protective layer (consistent with the embodiment, using low-density polyethylene film with a thickness of 0.1-0.2 mm).

[0059] 2. Materials and properties: The thermal storage material is a composite material of pure paraffin and expanded graphite (without added photothermal conversion reinforcing material), with a phase change temperature of 58-60 ℃, a latent heat of phase change of 204 J / g, and an absorptivity of 82% in the solar radiation band.

[0060] 3. Power generation performance test results: The average daily power generation is approximately 0.7 mW / cm². 2 The daytime temperature range is 18-23 degrees Celsius. C; At night, relying on the heat release of the thermal storage material and the radiative cooling effect, 6-10 The temperature difference (C) corresponds to an average nighttime power generation of approximately 0.15 mW / cm². 2 However, its power gradually diminishes over time, making it difficult to achieve continuous and stable power generation throughout the day.

[0061] Compared to the comparative example, the embodiments of the present invention improve the system's ability to maintain temperature difference and its power output capacity by introducing a synergistic mechanism of solar thermal energy storage and radiative cooling, achieving 24-hour continuous power generation; especially under nighttime conditions, it can still maintain 10 Temperature difference above °C with an output of 0.25-0.50 mW / cm 2 The power density of Comparative Example 1 is significantly higher than that of Comparative Example 2, which is essentially unable to generate electricity at night and exhibits weak nighttime power generation capacity that rapidly diminishes over time. Therefore, this invention demonstrates significant advantages in terms of continuous power generation capacity, nighttime power generation performance, and system operational stability.

[0062] The core test results of each embodiment and comparative example are summarized in the table below:

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling, comprising a thermoelectric generator, characterized in that, It also includes a heat collection and storage section and a cooling and cold storage section. The heat collection and storage section is located below the thermoelectric generator, and the cooling and cold storage section is located above the thermoelectric generator. The heat collection and storage section includes a photothermal conversion phase change material that converts solar radiation into heat energy and stores the heat energy. The cooling and cold storage section includes a radiation cooling and cold storage material that generates and stores the cold energy. By independently storing energy at both ends of the thermoelectric generator through the heat collection and storage section and the cooling and cold storage section, a continuous temperature difference is maintained between the two ends of the thermoelectric generator, enabling continuous power generation throughout the day.

2. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 1, characterized in that, The photothermal conversion phase change material is prepared by the following method: heating and melting the phase change material raw material, adding expanded graphite and photothermal conversion enhancement material, stirring and mixing evenly, and cooling to room temperature to obtain the photothermal conversion phase change material; the phase change material raw material is an organic phase change material or an inorganic phase change material; the photothermal conversion enhancement material is one of graphene, carbon nanotubes, and reduced graphene oxide.

3. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 2, characterized in that, The phase change material raw material has a mass fraction of 60%-90%, the expanded graphite has a mass fraction of 5%-20%, and the photothermal conversion reinforcing material has a mass fraction of 0.1%-2%; the sum of the mass fractions of all components is 100%.

4. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 2 or 3, characterized in that, The photothermal conversion phase change material has a phase change temperature of 50-80 ℃, a latent heat of phase change ≥150 J / g, and an absorptivity of ≥85% in the solar light band.

5. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 1, characterized in that, The radiation cooling and cold storage material is prepared by the following method: dissolving the polymer matrix in a solvent, then adding phase change microcapsules and mixing evenly, and obtaining the radiation cooling and cold storage material after the solvent evaporates.

6. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 5, characterized in that, The phase change microcapsules account for 30%-60% of the mass of the radiation cooling and cold storage material; the polymer matrix is ​​one of PDMS, PMMA, PVDF, PVA, and PS; and the solvent is one of acetone, ethyl acetate, cyclohexane, toluene, and DMF.

7. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to claim 5 or 6, characterized in that, The radiation-cooled storage material has a reflectivity of ≥85% in the solar band, an emissivity of ≥90% in the atmospheric window band, a phase change temperature of 10-30 ℃, and a latent heat of phase change of ≥60 J / g.

8. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to any one of claims 1-3, 5 and 6, characterized in that, The heat collection and storage section also includes an insulation layer, and the photothermal conversion phase change material is filled in the insulation layer.

9. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to any one of claims 1-3, 5 and 6, characterized in that, The refrigeration and cold storage section also includes a transparent protective layer that covers the radiation refrigeration and cold storage material.

10. The dual-energy storage continuous thermoelectric power generation device based on photothermal conversion and radiative cooling according to any one of claims 1-3, 5 and 6, characterized in that, The thermoelectric generator is a Bi2Te3-based thermoelectric generator, and the contact interfaces between the thermoelectric generator and the heat collection and storage part and the cooling and cold storage part are coated with thermally conductive silicone grease.

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