Double-fluid frequency division heat exchange type solar photo-thermal-photovoltaic recovery system

Abstract

The utility model provides a double-fluid frequency division heat exchange type solar photo-thermal-photovoltaic recovery system which comprises a condenser, a double-fluid frequency division heat collector and a photovoltaic device which are arranged from top to bottom. The double-fluid frequency division heat collector comprises outer layer glass, a glass heat collector I and a glass heat collector II which are sequentially arranged from top to bottom, and the outer layer glass is located at the focusing position below the condenser. A high-temperature frequency division fluid circulates in the glass heat collector I; low-temperature heat exchange fluid circulates in the glass heat collector II; the photovoltaic device comprises a photovoltaic cell, a conductive plate, a heat dissipation channel and an insulation device which are sequentially arranged from top to bottom; the photovoltaic cell is positioned below the glass heat collector II; the heat dissipation channel is communicated with the glass heat collector II and used for providing low-temperature heat exchange fluid for the glass heat collector II.

Description

Technical Field

[0001] The utility model relates to the technical field of solar photovoltaic technology, in particular to a dual-fluid frequency-dividing heat exchange type solar thermal-photovoltaic recovery system. Background Art

[0002] Among the currently available renewable energy resources, solar energy has the advantages of large total resources, wide distribution, clean use, and no resource depletion.

[0003] Currently, the main bottleneck in solar energy utilization lies in efficient full-spectrum utilization. CN107449163A proposes a dual-frequency photothermal-photovoltaic-thermoelectric coupled full-spectrum solar energy utilization system. This dual-frequency system not only reduces the thickness of the glass collector, thereby improving the overall device's portability, but also increases the absorption efficiency of the selective absorption fluid (water). Furthermore, a photovoltaic / thermoelectric hybrid device achieves higher power generation efficiency. Furthermore, secondary heating of the selective absorption fluid (water) not only cools the cold end of the thermoelectric device but also allows the selective absorption fluid (water) to reach a higher temperature.

[0004] However, this approach uses the same selective absorption fluid, flowing serially through the heat exchange channels at the base of the PV cells and the frequency-divided heat collection channels above them. This limits the ability to independently adjust the PV cell and collector temperatures. To lower the PV cell temperature, the fluid flow rate must be increased, but this also reduces the collector temperature, resulting in low heat recovery quality. Conversely, reducing the flow rate yields high-quality heat energy, but at the expense of increased PV cell temperature and reduced photovoltaic efficiency.

[0005] Furthermore, this method requires a fluid with high thermal conductivity and specific heat capacity, making water or water-based nanofluids the preferred fluid. However, water's boiling point at atmospheric pressure limits its temperature, making it difficult to achieve high-quality heat collection. Furthermore, high-temperature-resistant thermal oil-based nanofluids also suffer from poor thermal conductivity and mismatched frequency bands, making high-quality solar energy recovery very difficult.

[0006] Therefore, it is urgent to adopt a new structure to give full play to the advantages of the beam-split photothermal-photovoltaic system, so as to achieve efficient and low-cost full-spectrum utilization of solar energy.

[0007] In order to solve the above problems, people have been seeking an ideal technical solution. Utility Model Content

[0008] The purpose of the utility model is to address the deficiencies of the existing technology and thus provide a dual-fluid frequency-divided heat exchange type solar thermal-photovoltaic recovery system.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a dual-fluid frequency-divided heat exchange type solar thermal-photovoltaic recovery system, comprising a concentrator, a dual-fluid frequency-divided heat collector and a photovoltaic device arranged from top to bottom;

[0010] The dual-fluid frequency-dividing collector includes an outer layer of glass, a glass collector I, and a glass collector II, which are arranged in order from top to bottom, and the outer layer of glass is located at the focusing position below the concentrator; a high-temperature frequency-dividing fluid flows in the glass collector I; and a low-temperature heat exchange fluid flows in the glass collector II;

[0011] The photovoltaic device includes a photovoltaic cell, a conductive plate, a heat dissipation channel and an insulating device arranged in sequence from top to bottom; the photovoltaic cell is located below the glass collector II; the heat dissipation channel is connected to the glass collector II and is used to provide low-temperature heat exchange fluid to the glass collector II.

[0012] Furthermore, the dual-fluid frequency-dividing heat exchanger solar thermal-photovoltaic recovery system also includes a heat exchanger, the low-temperature fluid inlet of the heat exchanger is connected to the fluid outlet of the glass collector II, and the low-temperature fluid outlet of the heat exchanger is connected to the fluid inlet of the glass collector II; the fluid inlet of the glass collector I is connected to the high-temperature fluid outlet of the heat exchanger.

[0013] In one embodiment, the high-temperature frequency separation fluid is a nanofluid of Therminol VP-1 and silver nanoparticles, and the low-temperature heat exchange fluid is water.

[0014] This utility model offers substantial advantages and advancements over existing technologies. Specifically, it uses a high-temperature frequency-dividing fluid and a low-temperature heat exchange fluid to achieve dual-frequency division of the solar spectrum. A heat exchanger device transfers waste heat from the low-temperature heat exchange fluid to the high-temperature frequency-dividing fluid, giving it higher thermal energy, improving heat collection quality and the overall utilization rate of solar energy. Simultaneously, the high-temperature frequency-dividing fluid performs both frequency division and heat collection functions.

[0015] In addition, the use of low-temperature heat exchange fluid can not only perform secondary frequency division on the solar spectrum, overcoming the defect of poor selectivity of high-temperature frequency division fluid mainly composed of organic matter for the infrared band, but also reduce the temperature of photovoltaic cells through heat exchange, thereby improving the efficiency of the overall device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the present utility model.

[0017] Figure 2 This is a schematic diagram of the solar spectrum distribution during the dual-fluid frequency division process.

[0018] Figure 3It is a schematic diagram of the changes of PV cell temperature, heat collection temperature and comprehensive exergy efficiency with the flow rate of low-temperature heat exchange fluid in the present invention.

[0019] Figure 4 This is a schematic diagram of the changes in PV cell temperature, heat collection temperature and comprehensive exergy efficiency with the flow rate of high-temperature frequency-divided fluid in the present invention.

[0020] Figure 5 It is a schematic diagram of the variation of PV cell temperature, collector temperature and comprehensive exergy efficiency with heat exchange / frequency division fluid flow rate in the traditional system.

[0021] In the figure: 1. Concentrator; 2. Dual-fluid frequency-dividing collector; 3. Photovoltaic device; 4. Outer glass; 5. Glass collector; 6. Glass collector; 7. Photovoltaic cell; 8. Conductive plate; 9. Heat dissipation channel; 10. Insulation device; 11. Heat exchanger; 12. Heat storage tank. DETAILED DESCRIPTION

[0022] The technical solution of the present utility model is further described in detail below through specific implementation methods.

[0023] Example 1

[0024] The utility model comprises a concentrator 1, a dual-fluid frequency-dividing heat collector 2, a photovoltaic device 3, a heat exchanger 11 and a heat storage tank 12, wherein the concentrator 1, the dual-fluid frequency-dividing heat collector 2 and the photovoltaic device 3 are arranged in sequence from top to bottom.

[0025] The dual-fluid frequency-dividing collector 2 includes an outer layer of glass 4, a glass collector I 5, and a glass collector II 6, which are arranged in sequence from top to bottom, wherein the outer layer of glass 4 is located at the focusing point below the concentrator 1, and the outer layer of glass 4, the glass collector I 5, and the glass collector II 6 are all made of highly transmittance glass materials. Furthermore, in order to reduce heat loss, the outer layer of glass 4 and the glass collector I 5, the glass collector I 5 and the glass collector II 6, and the glass collector II 6 and the photovoltaic device 3 are all vacuum structures.

[0026] A high-temperature frequency-dividing fluid is passed through the glass collector I 5, and a low-temperature heat exchange fluid is passed through the glass collector II 6.

[0027] The photovoltaic device 3 includes a photovoltaic cell 7, a conductive plate 8, a heat dissipation channel 9 and an insulating device 10 arranged in sequence from top to bottom, wherein the photovoltaic cell 7 is located below the glass collector II 6.

[0028] The conductive plate 8 is located between the photovoltaic cell 7 and the heat dissipation channel 9, and plays the role of current conduction and heat conduction. Preferably, the conductive plate 8 is made of a material with excellent electrical conductivity and good thermal conductivity, so as to play the role of simultaneous current conduction and heat conduction.

[0029] One end of the heat dissipation channel 9 is connected to the glass heat collector II 6, and the other end is connected to the low-temperature heat exchange fluid supply device.

[0030] The insulating device 10 is located at the bottom of the photovoltaic device 3 and has good insulation performance and heat resistance characteristics, and is used to protect the safety of people and the device.

[0031] Preferably, the low-temperature heat exchange fluid is water, and the heat dissipation channel is made of a material with high thermal conductivity, such as aluminum; the high-temperature frequency division fluid is a nanofluid composed of Therminol VP-1 and silver nanoparticles. Therminol VP-1 has good thermal stability at high temperatures (>300°C), and silver nanoparticles have good light absorption and scattering properties, especially for short-wave radiation (such as near-infrared light). It has a high absorption capacity, thereby playing the role of frequency division and heat collection.

[0032] In a specific implementation, one end of the glass collector 15 is connected to a high-temperature frequency-dividing fluid supply device, and the other end is connected to the heat storage tank 12. In this embodiment, the heat storage tank device 12 is a high-temperature (>300°C) atmospheric pressure liquid working fluid heat storage tank, which is used to store the Therminol VP-1 and silver nanoparticle nanofluid after passing through the glass collector 5. This high-temperature nanofluid can subsequently provide thermal energy for other systems such as power generation and heating.

[0033] During operation, the low-temperature heat exchange fluid supply device inputs low-temperature heat exchange fluid into the heat dissipation channel 9. The low-temperature heat exchange fluid will carry away the heat generated by the photovoltaic cell 7 in the heat dissipation channel 9, absorb sunlight in the infrared band in the glass collector II 6, and transmit sunlight in the visible light range, thereby playing a role of frequency division absorption; at the same time, after flowing through the heat dissipation channel, the low-temperature heat exchange fluid continues to flow through the glass collector II 6 and finally flows to the low-temperature heat exchange fluid supply device or other storage tanks.

[0034] The working process of this embodiment is as follows: sunlight is concentrated on the dual-fluid frequency-dividing collector 2 through the concentrator 1. When the sunlight passes through the outer glass 4 and enters the glass collector I 5, the high-temperature frequency-dividing fluid in the glass collector I 5 will absorb short-wavelength sunlight with low photovoltaic efficiency, while the low-temperature heat exchange fluid in the glass collector II 6 will absorb infrared radiation without photoelectric conversion effect that the high-temperature frequency-dividing fluid has not absorbed, playing the role of secondary frequency division and preventing the photovoltaic cell efficiency from decreasing due to excessively high temperature.

[0035] The advantage of secondary frequency division is that it leverages the high-temperature resistance of the organic-based high-temperature frequency division fluid to improve heat collection quality while also ensuring the frequency division effect, selectively absorbing short-wave and long-wave radiation with low photovoltaic efficiency, thereby improving photovoltaic power generation efficiency. Furthermore, secondary frequency division can reduce the thickness of the glass collectors I 5 and II 6, increasing the portability of the dual-fluid frequency division collector 2.

[0036] Furthermore, visible sunlight passing through the glass collector II 6 is incident on the photovoltaic cell 7 for photoelectric conversion. The conductive plate 8 conducts current and simultaneously transfers heat generated by the photovoltaic cell 7. The low-temperature heat exchange fluid flowing through the heat dissipation channel 9 not only cools the cold end of the photovoltaic cell 7 but also uses the heat generated by the photovoltaic cell 7 to heat itself. The heated low-temperature heat exchange fluid then flows into the glass collector II 6 of the dual-fluid frequency division collector 2 for secondary frequency division of the sunlight.

[0037] Example 2

[0038] The difference between this embodiment 1 and embodiment 2 is that: it also includes a heat exchanger, the low-temperature fluid inlet of the heat exchanger 11 is connected to the fluid outlet of the glass collector II 6, and the low-temperature fluid outlet of the heat exchanger 11 is connected to the fluid inlet of the glass collector II 6; the fluid inlet of the glass collector I 5 is connected to the high-temperature fluid outlet of the heat exchanger 11.

[0039] During operation, the heat exchanger 11 inputs low-temperature heat exchange fluid into the heat dissipation channel 9. The low-temperature heat exchange fluid will carry away the heat generated by the photovoltaic cell 7 in the heat dissipation channel 9, absorb sunlight in the infrared band in the glass collector II 6, and transmit sunlight in the visible light range, thereby playing a role of frequency division absorption; at the same time, the low-temperature heat exchange fluid continues to flow through the glass collector II 6 after flowing through the heat dissipation channel 9 and finally returns to the heat exchanger 11, and the heat exchanger 11 preheats the high-temperature frequency division fluid flowing into the glass collector I 5 according to the low-temperature heat exchange fluid (water).

[0040] The working process of this embodiment is as follows: sunlight is concentrated on the dual-fluid frequency-dividing collector 2 through the concentrator 1. When the sunlight passes through the outer glass 4 and enters the glass collector I 5, the high-temperature frequency-dividing fluid in the glass collector I 5 will absorb short-wavelength sunlight with low photovoltaic efficiency, while the low-temperature heat exchange fluid in the glass collector II 6 will absorb infrared radiation without photoelectric conversion effect that the high-temperature frequency-dividing fluid has not absorbed, playing the role of secondary frequency division and preventing the photovoltaic cell efficiency from decreasing due to excessively high temperature.

[0041] The advantage of secondary frequency division is that it leverages the high-temperature resistance of the organic-based high-temperature frequency division fluid to improve heat collection quality while also ensuring the frequency division effect, selectively absorbing short-wave and long-wave radiation with low photovoltaic efficiency, thereby improving photovoltaic power generation efficiency. Furthermore, secondary frequency division can reduce the thickness of the glass collectors I 5 and II 6, increasing the portability of the dual-fluid frequency division collector 2.

[0042] Furthermore, visible sunlight passing through the glass collector II 6 will be incident on the photovoltaic cell 7 for photoelectric conversion. The conductive plate 8 conducts current and simultaneously transfers the heat generated by the photovoltaic cell 7. The low-temperature heat exchange fluid flowing through the heat dissipation channel 9 not only cools the cold end of the photovoltaic cell 7, but also uses the heat generated by the photovoltaic cell 7 to heat itself. After being heated, the low-temperature heat exchange fluid flows into the glass collector II 6 of the dual-fluid frequency-dividing collector 2, undergoing secondary frequency-dividing of the sunlight. Simultaneously, the heat collection process generated by the secondary frequency-dividing process causes the low-temperature heat exchange fluid to reach a higher temperature. It then flows into the heat exchanger 11 to preheat the high-temperature frequency-dividing fluid flowing into the glass collector I 5, bringing it to a higher temperature and thus achieving a higher heat collection quality.

[0043] Figure 2 From top to bottom, the spectral intensity distribution of radiation reaching the surface of the dual-fluid frequency-splitting heat exchange solar thermal-photovoltaic recycling system described in this embodiment, the spectral intensity distribution of radiation after passing through the nanofluid composed of Therminol VP-1 and silver nanoparticles within glass collector I 5, and the spectral intensity distribution of radiation reaching the surface of the photovoltaic (PV) cell after passing through the water within glass collector II 6. It can be seen that the initial spectrum does not overlap significantly with the high-efficiency region, indicating that the photovoltaic (PV) cell will generate a large amount of waste heat, leading to performance degradation. After passing through the high-temperature frequency-splitting fluid, the shortwave radiation in the high-efficiency region is absorbed by the silver nanoparticles, but the loss of longwave radiation is minimal, which can still cause overheating of the photovoltaic (PV) cell. After secondary frequency-splitting by the low-temperature heat exchange fluid, except for the majority of the spectrum in the high-efficiency region that reaches the cell surface, the remaining shortwave and longwave radiation in the low-efficiency region is effectively absorbed, demonstrating the advantages of dual-fluid frequency-splitting.

[0044] Another advantage of the dual-fluid frequency division adopted by the present invention is that the flow rates of the low-temperature heat exchange fluid and the high-temperature frequency division fluid can be independently controlled. Figure 3-4 As shown in the figure, increasing the flow rate of low-temperature heat exchange fluid will reduce the temperature of photovoltaic cells, while the collector temperature is affected by the reduction of the preheating temperature of the heat exchanger and only decreases within a very small range, and the comprehensive exergy efficiency of the system is maintained at a high level; increasing the flow rate of high-temperature frequency-dividing fluid will reduce the collector temperature. A certain degree of reduction in the collector temperature will reduce the radiative heat dissipation of the system to the environment and improve the exergy efficiency, but further reducing the collector temperature will make the collector grade too low and reduce the exergy efficiency. This process has almost no effect on the temperature of photovoltaic cells.

[0045] In contrast, in the traditional system of a dual-frequency-dividing solar thermal-photovoltaic-thermoelectric coupled solar full spectrum utilization system proposed in CN107449163A, since the heat exchange / frequency-dividing fluid flows through the heat dissipation channel and the glass collector in series, the fluid flow can only be controlled simultaneously, such as Figure 5 As shown, increasing the flow rate reduces the temperature of the photovoltaic cells, but also significantly reduces the heat collection temperature. However, too low a flow rate significantly degrades the efficiency of the photovoltaic cells due to the high temperature, resulting in a low overall exergy efficiency. By independently controlling the flow rates of the low-temperature heat exchange fluid and the high-temperature frequency-dividing fluid, the present invention allows both the PV cells and the heat collection system to operate within a high-performance range, achieving high-quality solar energy collection.

[0046] In summary, the present invention uses a high-temperature frequency-dividing fluid and a low-temperature heat exchange fluid to achieve dual frequency division of the solar spectrum. A heat exchanger is used to transfer the waste heat of the low-temperature heat exchange fluid to the high-temperature frequency-dividing fluid, giving the high-temperature frequency-dividing fluid higher thermal energy, thereby improving the heat collection quality and the comprehensive utilization rate of solar energy. At the same time, the high-temperature frequency-dividing fluid can perform both frequency division and heat collection. Furthermore, the use of a low-temperature heat exchange fluid not only allows for secondary frequency division of the solar spectrum, overcoming the poor selectivity of high-temperature frequency-dividing fluids based on organic matter for the infrared band, but also reduces the temperature of the photovoltaic cells through heat exchange, thereby improving the efficiency of the overall device. Therefore, this system has a wide range of applications, great social and economic benefits, and broad market prospects.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and not to limit it; although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the utility model can still be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solution of the utility model, they should all be included in the scope of the technical solution for protection of the utility model.

Claims

1. A dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system, characterized by: It includes a concentrator, a dual-fluid frequency-dividing collector and a photovoltaic device arranged from top to bottom; The dual-fluid frequency-dividing collector includes an outer layer of glass, a glass collector I, and a glass collector II, which are arranged in order from top to bottom, and the outer layer of glass is located at the focusing position below the concentrator; a high-temperature frequency-dividing fluid flows in the glass collector I; and a low-temperature heat exchange fluid flows in the glass collector II; The photovoltaic device includes a photovoltaic cell, a conductive plate, a heat dissipation channel and an insulating device arranged in sequence from top to bottom; the photovoltaic cell is located below the glass collector II; the heat dissipation channel is connected to the glass collector II and is used to provide low-temperature heat exchange fluid to the glass collector II.

2. The dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system according to claim 1, characterized in that: It also includes a heat exchanger, the low-temperature fluid inlet of the heat exchanger is connected to the fluid outlet of the glass collector II, and the low-temperature fluid outlet of the heat exchanger is connected to the fluid inlet of the glass collector II; the fluid inlet of the glass collector I is connected to the high-temperature fluid outlet of the heat exchanger.

3. A dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system according to claim 1 or 2, characterized in that: It also includes a heat storage tank, and the fluid outlet of the glass heat collector 1 is connected to the heat storage tank.

4. A dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system according to claim 1 or 2, characterized in that: The outer glass, the glass collector I, and the glass collector II are all made of highly light-transmitting glass materials.

5. The dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system according to claim 4, characterized in that: There is a vacuum structure between the outer glass and the glass collector I, between the glass collector I and the glass collector II, and between the glass collector II and the photovoltaic cell.

6. A dual-fluid frequency-divided heat exchange solar thermal-photovoltaic recovery system according to claim 1 or 2, characterized in that: The heat dissipation channel is an aluminum channel.

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