Photovoltaic and photo-thermal integrated assembly based on directional heat conduction phase change material

Abstract

The photovoltaic and photo-thermal integrated assembly comprises a glass cover plate layer, a photovoltaic plate layer, a heat absorption layer and a directional heat conduction phase change material layer which are sequentially arranged from top to bottom, and the directional heat conduction phase change material is prepared through an electrochemical method and a stress induction method; the glass cover plate layer, the photovoltaic plate layer, the heat absorption layer and the directional heat conduction phase change material layer form a plate-shaped assembly in a lamination mode, and the plate-shaped assembly is wrapped by the metal shell frame. A heat exchange metal coil pipe is arranged in the directional heat conduction phase change material layer, and a heat exchange medium inlet and a heat exchange medium outlet of the heat exchange metal coil pipe extend out of the metal shell frame. By utilizing the characteristics that the directional heat conduction phase change material is large in energy storage density and the temperature is not changed in the phase change process, the working temperature of the photovoltaic panel is effectively controlled, the photoelectric conversion efficiency is improved, the heat storage capacity of the assembly is greatly improved, and more domestic hot water use requirements of users are met.

Description

Technical Field

[0001] The present invention relates to the technical field of solar energy utilization, and in particular to a photovoltaic-thermal integrated component based on a directional heat-conducting phase-change material. Background Art

[0002] Solar photovoltaic and thermal integrated components integrate two forms of solar energy utilization: photovoltaic power generation and thermal utilization, greatly improving the efficiency of solar energy utilization. With the cost reduction brought about by the upgrading of the photovoltaic industry, photovoltaic and thermal integrated components have gradually become one of the mainstream solar energy utilization devices and are used in various building energy supply systems. The design and operation control of photovoltaic and thermal integrated components mainly balance the two opposite temperature requirements of low photovoltaic panel surface temperature under the demand for high photoelectric conversion efficiency and high water supply temperature at the outlet water temperature to ensure user needs. Photovoltaic and thermal integrated components usually use water cooling to cool photovoltaic panels. Because the surface temperature of photovoltaic panels is too high under normal working conditions, the circulating water temperature used for cooling is relatively low. The outlet water temperature after cooling cannot meet the user's hot water demand, and an additional heat pump system needs to be added for further heating, which increases energy consumption. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a photovoltaic-thermal integrated component based on directional heat-conducting phase change material, which can stably control the working temperature of photovoltaic panels and provide hot water to users without the need for an additional heat pump system.

[0004] Technical solution: The photovoltaic-thermal integrated component based on directional heat-conducting phase change material described in the present invention comprises a glass cover layer, a photovoltaic panel layer, a heat-absorbing layer and a directional heat-conducting phase change material layer arranged in sequence from top to bottom, and the directional heat-conducting phase change material is prepared by an electrochemical method and a stress-inducing method; the glass cover layer, the photovoltaic panel layer, the heat-absorbing layer and the directional heat-conducting phase change material layer are formed into a plate-like component by lamination, and the plate-like component is coated by a metal shell frame; a heat-exchange metal coil is arranged in the directional heat-conducting phase change material layer, and the heat-exchange medium inlet and the heat-exchange medium outlet of the heat-exchange metal coil extend out of the metal shell frame.

[0005] Furthermore, the directional heat-conducting phase change material is prepared by an electrochemical method and a stress-inducing method, including: using an electrolytic cell to apply a directional current to metal powder in an electrolyte, controlling the current size to keep a constant vertical deposition rate, and forming a metal heat-conducting skeleton with a regular layered stacking form; filling the metal heat-conducting skeleton with a phase-change energy storage material, and changing the structure of the heat-conducting filler in the phase-change energy storage material by stress-induction, so that the microstructure arrangement direction of the heat-conducting filler is consistent with the heat flow transfer direction, forming a quasi-parallel structure, reducing the equivalent thermal resistance, and reducing the thermal resistance of the phase change material.

[0006] The prepared directional thermal conductive phase change material can overcome the problem that it is difficult to balance the thermal conductivity and energy storage density of the composite material by directly adding thermal conductive fillers. The preparation operation is relatively easy and has the potential for large-scale production and application.

[0007] Furthermore, evenly distributed metal fins are provided at the bottom of the heat absorption layer, and the metal fins can enhance the heat exchange effect between the heat absorption layer and the directional heat conducting phase change material layer.

[0008] Furthermore, the heat absorption layer is made of borosilicate nanoshell material, and the heat absorption layer is electroplated with a black chromium coating, a black nickel coating or a black cobalt coating that selectively absorbs the spectrum. The use of excellent heat absorption layer materials and coatings can enhance the spectral absorption capacity of sunlight.

[0009] Furthermore, the metal shell frame is a hollow sandwich structure, in which corrugated metal plates for support are arranged, and between the corrugated metal plates are filled with heat-insulating materials.

[0010] Furthermore, the material of the thermal insulation material is one or more of rubber-plastic cotton, polyester cotton, polyurethane cotton, and polystyrene cotton.

[0011] Furthermore, foam metal fins are arranged on the outer circumferential surface of the heat exchange metal coil.

[0012] Furthermore, the distribution of the foam metal fins is dense at the top and sparse at the bottom, and each foam metal fin has a fractal short rib at an angle of 90 degrees at the end, and the fractal short rib forms an angle of 45 degrees with the base rib.

[0013] The heat exchange metal coils are equipped with non-uniformly distributed foam metal fins. This arrangement is designed to prevent the heat accumulation effect at the top of the phase change material due to gravity and the heat convection during the heat exchange of low-temperature heat exchange media. This arrangement can speed up the heat exchange rate of the phase change material at the top, and the fractal structure at the end further enhances the heat exchange capacity at the end of the pipe edge, thereby reducing the problem of reduced power generation efficiency caused by heat accumulation.

[0014] Furthermore, the foam metal fins are directly fired and fixed to the heat exchange metal coil, and this fixing method can effectively reduce the problem of large contact thermal resistance existing in welding.

[0015] Furthermore, the porosity of the foam metal fins is greater than or equal to 90%, which can reduce the volume occupied by the fins and increase the overall energy storage density.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0017] The present invention prepares directional heat-conducting phase change materials by electrochemical method and stress induction method. The internal heat-conducting filler is consistent with the direction of heat flow transfer. From a microscopic perspective, it can be equivalent to a parallel form of a pile of thermal resistors, thereby greatly reducing the thermal resistance of the phase change material, and having higher thermal conductivity and better heat storage capacity. The phase change material has a fixed temperature during phase change. The directional heat-conducting phase change material is used to control the temperature of the photovoltaic panel, and the surface temperature of the photovoltaic panel can be kept constant under high heat flow transfer, thereby improving the photoelectric conversion efficiency. In addition, the high heat storage capacity of the directional heat-conducting phase change material can be used to further increase the outlet water temperature, and the outlet water temperature can also be maintained constant under low sunlight intensity, meeting the user's demand for more domestic hot water, reducing the user's building energy consumption, and improving the operation stability of the photovoltaic thermal integration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional schematic diagram of a photovoltaic-thermal integrated component based on a directional heat-conducting phase change material provided by an embodiment of the present invention;

[0019] Figure 2 is a schematic top view of a directional heat-conducting phase change material layer in an embodiment of the present invention;

[0020] Figure 3 Schematic diagram of the foam metal fin structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] Attached Figures 1 to 3 The reference numerals in the figures are as follows:

[0023] 1. Glass cover layer; 2. Photovoltaic panel layer; 3. Heat absorption layer; 4. Directional heat conduction phase change material layer; 5. Metal shell frame; 6. Thermal insulation material; 7. Metal fins; 8. Heat exchange metal coil; 9. Foam metal fins; 10. Heat exchange medium inlet; 11. Heat exchange medium outlet.

[0024] like Figures 1 to 3 As shown, an embodiment of the present invention provides a photovoltaic-thermal integrated component based on a directional heat-conducting phase change material, comprising a glass cover layer 1, a photovoltaic panel layer 2, a heat-absorbing layer 3 and a directional heat-conducting phase change material layer 4 arranged in sequence from top to bottom.

[0025] The bottom of the heat absorption layer 3 is provided with uniformly distributed metal fins 7. The heat absorption layer 3 is made of silicon boride nanoshell material, and the heat absorption layer 3 is electroplated with a black chromium coating, a black nickel coating or a black cobalt coating that selectively absorbs the spectrum. These coatings have excellent spectral selectivity, thermal stability and high temperature resistance, and are suitable for solar thermal utilization under high temperature conditions.

[0026] Directional thermal conduction phase change materials have directional thermal conduction capabilities and are prepared by electrochemical and stress-induced methods, including:

[0027] An electrolytic cell is used to apply a directional current to the metal powder in the electrolyte, and the current size is controlled to keep the vertical deposition rate at 20μm / s to form a metal thermal conductive skeleton with a regular layered stacking form; the phase change energy storage material is filled into the metal thermal conductive skeleton, and the structure of the thermal conductive filler in the phase change energy storage material is changed by stress induction, so that the microstructure arrangement direction of the thermal conductive filler is consistent with the direction of heat flow transfer, forming a quasi-parallel structure, reducing the equivalent thermal resistance, and reducing the thermal resistance of the phase change material.

[0028] This directional heat-conducting phase change material can overcome the problem that it is difficult to balance the thermal conductivity and energy storage density of the composite material by directly adding thermal conductive fillers. It is also easy to prepare and operate, and has the potential for large-scale production and application.

[0029] The glass cover layer 1, the photovoltaic panel layer 2, the heat absorption layer 3 and the directional heat-conducting phase change material layer 4 are laminated to form a plate-shaped assembly, and the plate-shaped assembly is covered by a metal shell frame 5. A heat-exchange metal coil 8 is arranged in the directional heat-conducting phase change material layer 4, and a heat-exchange medium inlet 10 and a heat-exchange medium outlet 11 of the heat-exchange metal coil 8 extend out of the metal shell frame 5.

[0030] The metal shell frame 5 is a hollow sandwich structure, in which a corrugated metal plate for support is arranged, and between the corrugated metal plates are filled with insulation material 6. The corrugated metal plate can reduce the mass and cost of the shell, and at the same time provide space for filling the insulation material 6. The insulation material 6 is made of one or more of rubber-plastic cotton, polyester cotton, polyurethane cotton, and polystyrene cotton.

[0031] The heat exchange metal coil 8 is in the shape of a serpentine coil. The material of the heat exchange metal coil 8 is preferably copper with high thermal conductivity.

[0032] Foam metal fins 9 are arranged on the outer circumferential surface of the heat exchange metal coil 8. The foam metal fins 9 are directly fired and fixed to the heat exchange metal coil 8, which can effectively reduce the problem of large contact thermal resistance existing in welding.

[0033] The distribution of the foam metal fins 9 is dense at the top and sparse at the bottom. A fin is arranged every 30° in the upper part, and a fin is arranged every 45° in the lower part. At the end of each foam metal fin 9, there is a fractal short rib with a 90° angle, and the fractal short rib is at a 45° angle with the base rib. This arrangement is aimed at the heat accumulation effect at the top of the phase change material due to the gravity during the heat exchange process of the low-temperature heat exchange medium. This arrangement can speed up the heat exchange rate of the top phase change material, and the fractal structure at the end further strengthens the heat exchange capacity at the end of the pipe edge, thereby reducing the problem of reduced power generation efficiency caused by heat accumulation.

[0034] The porosity of the foam metal fins 9 is greater than or equal to 90%, which can reduce the volume occupied by the fins and increase the overall energy storage density of the component.

[0035] In actual use, a certain temperature detection device can be used to monitor the inlet and outlet temperatures of the heat exchange metal coil 8, and a variable frequency water pump can be used to adjust the heat exchange medium flow rate, which can further control the temperature of the photovoltaic panel assembly. At the same time, an adjustable bracket can also be set at the bottom of the assembly to change the slope of the photovoltaic assembly according to the sun's angle, thereby improving the solar energy utilization rate of the photovoltaic thermal integration assembly.

[0036] The present invention realizes the transfer and utilization of heat energy by exchanging heat between the heat exchange medium flowing in the heat exchange metal coil 8 and the directional heat conduction phase change material layer 4 after heat storage. Combining the photoelectric conversion and light-heat conversion effects of the photovoltaic panel, the directional heat conduction phase change material is used for energy storage and energy release, which can realize the cascade utilization of the full spectrum of solar energy, improve the overall energy storage capacity of the component, reduce the heat exchange resistance, strengthen the heat exchange effect of the component, control the temperature of the photovoltaic panel component, and improve the photovoltaic power generation efficiency, so it has good technical effects and application value.

Claims

1. A photovoltaic-thermal integrated component based on directional heat-conducting phase change material, characterized in that: The invention comprises a glass cover layer (1), a photovoltaic panel layer (2), a heat absorption layer (3) and a directional heat conduction phase change material layer (4) which are arranged in sequence from top to bottom, wherein the directional heat conduction phase change material is prepared by an electrochemical method and a stress induction method; the glass cover layer (1), the photovoltaic panel layer (2), the heat absorption layer (3) and the directional heat conduction phase change material layer (4) are laminated to form a plate-shaped component, and the plate-shaped component is coated by a metal shell frame (5); a heat exchange metal coil (8) is arranged in the directional heat conduction phase change material layer (4), and a heat exchange medium inlet (10) and a heat exchange medium outlet (11) of the heat exchange metal coil (8) extend out of the metal shell frame (5).

2. The photovoltaic-thermal integrated assembly according to claim 1, characterized in that: The directional heat-conducting phase-change material is prepared by an electrochemical method and a stress-inducing method, including: using an electrolytic cell to apply a directional current to metal powder in an electrolyte, controlling the current size to keep a constant vertical deposition rate, and forming a metal heat-conducting skeleton with a regular layered stacking form; filling the metal heat-conducting skeleton with a phase-change energy storage material, and changing the structure of the heat-conducting filler in the phase-change energy storage material by stress-induction, so that the microstructure arrangement direction of the heat-conducting filler is consistent with the heat flow transfer direction, forming a parallel-like structure.

3. The photovoltaic-thermal integrated assembly according to claim 1, characterized in that: The bottom of the heat absorption layer (3) is provided with evenly distributed metal fins (7).

4. The photovoltaic-thermal integrated assembly according to claim 1, characterized in that: The heat absorption layer (3) is made of borosilicate nanoshell material, and a black chromium coating, a black nickel coating or a black cobalt coating that selectively absorbs the spectrum is electroplated on the heat absorption layer (3).

5. The photovoltaic-thermal integrated assembly according to claim 1, characterized in that: The metal shell frame (5) is a hollow sandwich structure, in which corrugated metal plates for support are arranged, and between the corrugated metal plates there are filled thermal insulation materials (6).

6. The photovoltaic-thermal integrated assembly according to claim 5, characterized in that: The material of the heat-insulating material (6) is one or more of rubber-plastic cotton, polyester cotton, polyurethane cotton, and polystyrene cotton.

7. The photovoltaic-thermal integrated assembly according to claim 1, characterized in that: Foam metal fins (9) are arranged on the outer circumferential surface of the heat exchange metal coil (8).

8. The photovoltaic-thermal integrated assembly according to claim 7, characterized in that: The distribution form of the foam metal fins (9) is dense at the top and sparse at the bottom. The end of each foam metal fin (9) has a fractal short rib with an angle of 90 degrees, and the fractal short rib and the base rib form an angle of 45 degrees.

9. The photovoltaic-thermal integrated assembly according to claim 8, characterized in that: The foam metal fins (9) are directly fired and fixed to the heat exchange metal coil (8).

10. The photovoltaic-thermal integrated assembly according to claim 8, characterized in that: The porosity of the foam metal fin (9) is greater than or equal to 90%.

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