A phase change energy storage type high-efficiency collector cover plate

Abstract

The application discloses a phase change energy storage type high-efficiency heat collector cover plate; the cover plate is formed by stacking a plurality of heat storage plates on the upper and lower parts and is arranged on the front surface of a photovoltaic module, and a heat storage box is arranged on the back surface of the photovoltaic module; the heat storage box is connected to the heat storage plate through a heat transfer structure, and the heat transfer structure is suitable for one-way transmission of the heat absorbed by the heat storage plate to the heat storage box. The application has the beneficial effects that: through the arrangement of the heat storage plate on the front surface of the photovoltaic module and the arrangement of the heat storage box on the back surface of the photovoltaic module, the heat storage plate and the heat storage box are connected through the heat transfer structure, the waste heat generated by the photovoltaic module in the daytime is collected through the heat storage plate and is transmitted to the heat storage box for storage, the working of the photovoltaic module in the daytime is cooled, and the efficiency of the photovoltaic module is improved; and the heat stored in the heat storage box is kept warm for the photovoltaic module at night, so that the photovoltaic module is prevented from being damaged due to low temperature.

Description

Technical Field

[0001] This application relates to the field of solar collectors, and in particular to a phase change energy storage type high-efficiency solar collector cover plate. Background Technology

[0002] The collector cover is a core functional component of a photovoltaic-thermal integrated system, and its thermal management performance directly affects the operating temperature, power generation efficiency, and long-term operational reliability of the photovoltaic modules. An excellent cover design must balance efficient light transmission with active thermal regulation to ensure stable and efficient system operation under all-weather conditions.

[0003] Traditional cover plate designs typically use ordinary glass or transparent polymer materials, providing only basic light transmission and encapsulation protection, lacking the ability to store and release heat. These traditional covers cannot effectively mitigate module temperature rise during the day, leading to power generation efficiency losses. Especially at night or in low-temperature environments, the cover cannot replenish heat, potentially causing a sudden drop in module temperature and frost formation, or repeated thermal shocks leading to microcracks in the cells, accelerated aging of encapsulation materials, and in severe cases, even permanent performance degradation and structural damage. As the performance and reliability requirements of photovoltaic systems continue to increase, traditional cover plates without energy storage, due to their lack of thermal management capabilities, are no longer sufficient to meet the application needs under complex operating conditions. Therefore, a new solution is urgently needed. Utility Model Content

[0004] The purpose of this application is to provide a phase change energy storage type high-efficiency solar collector cover that can solve at least one of the defects in the above-mentioned background technology.

[0005] To achieve at least one of the above objectives, this application provides a phase change energy storage type high-efficiency solar collector cover plate, including a heat storage box and multiple heat storage plates. The heat storage plates are stacked to form a cover plate and disposed on the front side of the photovoltaic module, and the heat storage box is disposed on the back side of the photovoltaic module. The heat storage box is connected to the heat storage plates through a heat transfer structure, and the heat transfer structure is adapted to unidirectionally transfer the heat absorbed by the heat transfer plates to the heat storage box.

[0006] Preferably, the heat transfer structure includes multiple flow channels, a phase change working fluid, and a heat storage working fluid; one end of each flow channel is connected to the upper end of the heat storage plate, and the other end passes through the heat storage box and is connected to the lower end of the heat storage plate; the flow channel is unidirectional from top to bottom; multiple heat storage plates correspond to different flow channels, and a single heat storage plate is connected to multiple spaced flow channels in a horizontal direction; the phase change working fluid is disposed inside the heat storage plate, absorbs heat from the photovoltaic module and changes phase to gas, and then heats the heat storage working fluid located in the heat storage box through the flow channels; the phase change working fluid is adapted to change phase to liquid after heating and flow back into the heat storage plate.

[0007] Preferably, the phase change working fluid in each of the thermal storage plates has a different phase change temperature, with the phase change temperature of the outer phase change working fluid being lower than that of the inner phase change working fluid.

[0008] Preferably, each of the heat storage plates has a different thickness, with the outer heat storage plate having a smaller thickness than the inner heat storage plate.

[0009] Preferably, the number of heat storage plates is 2-4.

[0010] Preferably, the heat storage medium is a fluid.

[0011] Preferably, the cross-sectional shape of the flow channel is circular or elliptical.

[0012] Preferably, the volume of the flow channel corresponding to a single heat storage plate is 10%-15% of the volume of the heat storage plate.

[0013] Preferably, a one-way valve is provided at the connection position between the flow channel pipe and the lower end of the heat storage plate.

[0014] Preferably, an optical layer for reducing light reflection is provided between two adjacent heat storage plates.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: In the technical solution of this application, by setting a heat storage plate on the front of the photovoltaic module and a heat storage box on the back of the photovoltaic module, the heat storage plate and the heat storage box are connected by a heat transfer structure. The waste heat generated by the photovoltaic module during the day is collected by the heat storage plate and transferred to the heat storage box for storage. This not only cools down the photovoltaic module during the day and improves the efficiency of the photovoltaic module, but also keeps the heat stored in the heat storage box of the photovoltaic module warm at night, preventing the photovoltaic module from being damaged due to low temperature. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a cross-sectional schematic diagram of the present invention.

[0018] In the figure: thermal storage plate 1, first thermal storage plate 110, first phase change working medium 111, second thermal storage plate 120, second phase change working medium 121, flow channel pipe 2, thermal storage box 3, thermal storage working medium 310, photovoltaic module 4, optical layer 5. Detailed Implementation

[0019] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0020] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0021] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0022] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0023] A preferred embodiment of this application, such as Figure 1 and Figure 2 As shown, a phase change energy storage type high-efficiency solar collector cover plate includes a heat storage box 3 and multiple heat storage plates 1. The heat storage plates 1 are stacked one on top of the other to form a cover plate and are disposed on the front side of the photovoltaic module 4. The heat storage box 3 is disposed on the back side of the photovoltaic module 4. The heat storage box 3 is connected to the heat storage plates 1 through a heat transfer structure. The heat transfer structure is adapted to transfer the heat absorbed by the heat transfer plates unidirectionally to the heat storage box 3.

[0024] It should be understood that during the daytime operation of photovoltaic module 4, a large amount of waste heat is generated. Some of this waste heat is directly transferred to the heat storage box 3 through the back of photovoltaic module 4, while most of the waste heat is generated from the front of photovoltaic module 4. Therefore, the heat storage plate 1 is located on the front of photovoltaic module 4, which can absorb a large amount of heat and continuously transfer it to the heat storage box 3 through the heat transfer structure. On the one hand, the waste heat of photovoltaic module 4 is directly absorbed by the heat storage plate 1 on the front and the heat storage box 3 on the back, so that photovoltaic module 4 can maintain a low temperature during the daytime operation, thus effectively improving the working efficiency of photovoltaic module 4. On the other hand, when the temperature drops sharply at night, the heat stored in the heat storage box 3 during the day can be continuously output to keep photovoltaic module 4 warm and prevent photovoltaic module 4 from being damaged due to low temperature.

[0025] Understandably, multiple heat storage plates 1 are stacked one on top of the other on the front of the photovoltaic module 4, forming a tiered heat absorption and storage structure. Not only can each heat storage plate 1 absorb the waste heat generated by the photovoltaic module 4 individually, but heat can also be transferred between the multiple layers of heat storage plates 1, thus forming a relatively continuous temperature gradient in the direction perpendicular to the photovoltaic module 4. This arrangement of heat storage plates 1 can achieve balanced absorption of waste heat layer by layer, avoiding local overheating of the inner layers; and the multi-layer heat storage plate 1 design increases the effective heat exchange area, allowing heat to be absorbed more fully by the heat storage plates 1, greatly reducing heat dissipation into the environment, and comprehensively improving the efficiency of heat absorption and storage.

[0026] It should also be noted that the heat transfer structure should unidirectionally transfer the heat absorbed by the heat storage plate 1 from the photovoltaic module 4 to the heat storage box 3. Therefore, the heat storage box 3 should have a strong heat storage capacity and the temperature should be controlled to be lower than that of the heat storage plate 1, so that the heat absorbed by the heat storage plate 1 can be continuously transferred to the heat storage box 3, and the heat will not be lost due to the temperature of the heat storage box 3 being higher than that of the heat storage plate 1.

[0027] It is also understandable that the heat transfer structure should have a fast heat transfer path so that the heat absorbed by the heat storage plate 1 can be transferred to the heat storage box 3 for storage as soon as possible. Therefore, using a fluid working medium instead of a solid working medium will greatly improve the heat transfer efficiency.

[0028] The heat transfer structure must effectively and quickly transfer the heat absorbed by the heat storage plate 1 to the heat storage box 3 in one direction. A preferred embodiment of this application is as follows: Figure 1 and Figure 2 As shown, the heat transfer structure includes multiple flow channels 2, a phase change working fluid, and a heat storage working fluid 310. One end of the flow channel 2 is connected to the upper end of the heat storage plate 1, and the other end passes through the heat storage box 3 and is connected to the lower end of the heat storage plate 1. The flow channel 2 is unidirectional from top to bottom. Multiple heat storage plates 1 correspond to different flow channels 2, and a single heat storage plate 1 is connected to multiple flow channels 2 arranged at intervals along the horizontal direction. The phase change working fluid is placed inside the heat storage plate 1. The phase change working fluid absorbs the heat of the photovoltaic module 4 and changes phase to gas, and then heats the heat storage working fluid 310 located in the heat storage box 3 through the flow channels 2. The phase change working fluid is suitable to change phase to liquid after heating and flow back into the heat storage plate 1.

[0029] It should be noted that the thermal storage plate 1 and the flow channel 2 are connected, and the phase change working fluid can circulate between the thermal storage plate 1 and the flow channel 2. Since the photovoltaic module 4 is tilted to receive sunlight, both the thermal storage plate 1 and the thermal storage box 3 are tilted and attached to the photovoltaic module 4. In this embodiment, the phase change working medium should be a liquid-gas conversion material. When the phase change working medium is in the heat storage plate 1, it is initially in a liquid state. After the phase change working medium absorbs the heat generated by the photovoltaic module 4 and stores a large amount of heat, it vaporizes and converts into a gaseous state. Then it rises and enters the heat storage box 3 through the flow channel pipe 2 connected to the upper end of the heat storage plate 1. In the heat storage box 3, it exchanges heat with the heat storage medium 310 and transfers the heat to the heat storage medium 310. After that, the phase change working medium liquefies and converts into a liquid state. It is then connected to the lower end of the heat storage plate 1 through the flow channel pipe 2 and enters the heat storage plate 1 again to carry out the cycle of heating vaporization and heat release liquefaction. This continuously transfers the waste heat from the front of the photovoltaic module 4 to the heat storage box 3 on the back of the photovoltaic module 4.

[0030] It is understandable that both the thermal storage plate 1 and the phase change working fluid should be transparent. Only transparent materials can allow light to pass through and irradiate the photovoltaic module 4 to work. Therefore, the thermal storage plate 1 can be made of transparent materials with a certain strength, such as glass. The phase change working fluid should be made of a transparent and stable material that has a vaporization point between room temperature and the operating temperature of the photovoltaic module 4.

[0031] Specifically, a one-way valve (not shown) is provided at the connection position between the flow channel pipe 2 and the lower end of the heat storage plate 1. The one-way valve can ensure that the liquefaction flow direction of the phase change material remains fixed and does not cause backflow.

[0032] It should be understood that the check valve must be installed at the connection point between the flow channel pipe 2 and the lower end of the heat storage plate 1, close to the inflow end of the heat storage tank 3, and cannot be installed at the outflow end. If it is installed at the outflow end, it cannot effectively prevent backflow. Furthermore, if the check valve is installed at the outflow end, the pressure difference between the two ends of the liquid alone is insufficient to overcome the valve's opening pressure, which will lead to interruption of backflow and disruption of the circulation. Therefore, the check valve must be installed at the connection point between the flow channel pipe 2 and the lower end of the heat storage plate 1, close to the inflow end of the heat storage tank 3.

[0033] More specifically, such as Figure 2 As shown, the thermal storage medium 310 is a fluid medium.

[0034] It should be understood that the heat storage medium 310 should be a fluid with high heat capacity, high thermal conductivity, and good and stable chemical properties. The heat storage medium 310 is filled in the heat storage tank 3 and is responsible for receiving and storing the latent heat released by the gaseous phase change medium in the flow channel 2. If a solid medium is used, due to its poor thermal conductivity, the part close to the flow channel 2 will have fully absorbed heat and liquefied, while the part far from the flow channel 2 will have difficulty acquiring heat and will remain solid. In this case, heat exchange will be severely blocked, and the heat storage effect of the heat storage tank 3 cannot be fully utilized. Therefore, in this embodiment, a fluid medium is preferred for the heat storage medium 310.

[0035] The inner heat storage plate 1, closer to the photovoltaic module 4, absorbs more heat. Therefore, the phase change working fluid of each heat storage plate 1 should be set in a gradient. A preferred embodiment of this application is as follows: Figure 2 As shown, the phase change temperature of the phase change working medium in each heat storage plate 1 is different, and the phase change temperature of the phase change working medium on the outside is lower than that of the phase change working medium on the inside.

[0036] It should be understood that in the structure of multiple heat storage plates 1 stacked on top of each other, the inner heat storage plate 1, being closer to the photovoltaic module 4, can absorb more and more concentrated waste heat, and its heat absorption is significantly higher than that of the outer heat storage plate 1. Therefore, in order to achieve more efficient and balanced heat absorption in the vertical direction, the phase change working medium in the heat storage plate 1 has a phase change temperature that decreases layer by layer from the inside to the outside. That is, the phase change temperature of the first phase change working medium 111 is lower than that of the second phase change working medium 121, so that the heat storage plate 1 with higher temperature on the inside can be transferred to the heat storage plate 1 with lower temperature on the outside layer by layer. This not only significantly improves the overall heat exchange efficiency and heat absorption capacity, but also effectively reduces the temperature fluctuation on the surface of the photovoltaic module 4.

[0037] By using different phase change temperatures for each layer of phase change working fluid, the overall heat exchange efficiency can be improved more reasonably. Furthermore, by using different thicknesses of the heat storage plate 1, i.e., different thicknesses of the phase change working fluid, the overall heat exchange efficiency can be further optimized. A preferred embodiment of this application is as follows... Figure 2 As shown, the thickness of each thermal storage plate 1 is different, with the outer thermal storage plate 1 having a smaller thickness than the inner thermal storage plate 1.

[0038] It should be understood that the second heat storage plate 120, which is located on the inner side, is closer to the photovoltaic module 4. Therefore, since the second heat storage plate 120 absorbs more heat, its thickness needs to be greater to accommodate a larger volume of phase change working fluid to match the heat absorption requirements. Correspondingly, the thickness of the heat storage plates 1 decreases step by step from the inside to the outside. In this embodiment, the first heat storage plate 110, which is located on the outer side, absorbs less heat. Therefore, in terms of materials, the thickness can be reduced to avoid material waste. Furthermore, the thinner phase change working fluid layer allows the phase change working fluid to absorb heat more fully and quickly.

[0039] It is understandable that although the thermal storage plate 1 and the phase change working fluid are made of transparent materials, they will still weaken the light to a certain extent, which will affect the working efficiency of the photovoltaic module 4. Therefore, reducing the thickness of the outer thermal storage plate 1 can significantly improve the light level received by the photovoltaic module 4 without greatly reducing the overall heat absorption efficiency, so that the efficiency of the photovoltaic module 4 can be kept in a high range.

[0040] If the number of thermal storage plates 1 is too large, it will seriously affect the amount of sunlight received by the photovoltaic module 4. In a preferred embodiment of this application, such as... Figure 1 and Figure 2 As shown, the number of thermal storage plates 1 is 2-4.

[0041] It should be understood that while increasing the number of thermal storage panels 1 can improve the overall heat absorption capacity, the physical shading caused by the stacking of thermal storage panels 1 will weaken the light intensity received by the photovoltaic module 4, thereby reducing the conversion efficiency of the photovoltaic module 4. Therefore, to achieve a better balance between photovoltaic power generation and heat storage, this embodiment preferably uses two thermal storage panels 1.

[0042] It is understandable that appropriately increasing the number of thermal storage plates 1 can make the inner thermal storage plates 1 less affected by the ambient temperature, and can exchange heat with the photovoltaic module 4 more stably.

[0043] Since the flow channel 2 serves to introduce the phase change working fluid into the heat storage tank 3 and exchange heat with the heat storage working fluid 310 through its boundary, the shape of the flow channel 2 should promote improved heat exchange efficiency between the phase change working fluid and the heat storage working fluid 310. A preferred embodiment of this application is as follows... Figure 1 and Figure 2 As shown, the cross-sectional shape of the flow channel 2 is circular or elliptical.

[0044] It should be understood that the cross-sectional shape of the flow channel 2 significantly affects the heat exchange efficiency between the phase change working fluid and the heat storage working fluid 310. Besides transporting the phase change working fluid, the core function of the flow channel 2 is, more importantly, to facilitate heat exchange through the pipe wall boundary within the heat storage tank 3. Therefore, the cross-sectional shape of the flow channel 2 should maximize its heat exchange area and reduce flow resistance, thereby significantly improving the heat exchange efficiency between the phase change working fluid and the heat storage working fluid 310. Thus, in this embodiment, the cross-sectional shape of the flow channel 2 is preferably circular or elliptical. A circular cross-section has the advantages of uniform structure, good pressure resistance, and mature manufacturing process, and can provide a larger heat exchange area within the same volume compared to a rectangular cross-section. An elliptical cross-section can also provide a much larger effective contact perimeter than a rectangular cross-section. The parameters of the elliptical cross-section can be adjusted according to the design shape of the heat storage tank 3, thereby enabling a more efficient heat exchange process within the limited space of the heat storage tank 3.

[0045] A preferred embodiment of this application, such as Figure 2 As shown, the volume of the flow channel 2 corresponding to a single heat storage plate 1 is 10%-15% of the volume of the heat storage plate 1.

[0046] It should be understood that if the volume of the flow channel 2 is too small compared to the volume of the heat storage plate 1, the area available for the flow and heat exchange of the vaporized phase change working fluid will be insufficient, limiting the flow rate and volume of the phase change working fluid, and reducing the heat exchange area, thus limiting the heat exchange efficiency between the phase change working fluid and the heat storage working fluid 310. If the volume of the flow channel 2 is too large compared to the volume of the heat storage plate 1, although the heat exchange capacity can be improved, too much phase change working fluid will condense and liquefy prematurely. Due to the limited force of gravity return, it is difficult to effectively transport a large amount of liquid working fluid back to the heat storage plate 1, resulting in blockage of the flow channel 2 and inability to operate continuously. Therefore, in this embodiment, the volume of the flow channel 2 corresponding to a single heat storage plate 1 is preferably 10%-15% of the volume of the heat storage plate 1.

[0047] A preferred embodiment of this application, such as Figure 2 As shown, an optical layer 5 for reducing light reflection is provided between two adjacent heat storage plates 1.

[0048] It should be understood that the different thicknesses of the first thermal storage plate 110 and the second thermal storage plate 120, as well as the different materials of the first phase change working medium 111 and the second phase change working medium 121, lead to different refractive indices, resulting in partial light reflection and reducing the amount of light reaching the photovoltaic module 4. Therefore, an optical layer 5 is provided between two adjacent thermal storage plates 1 to achieve a transition in refractive index between the different thermal storage plates 1, significantly reducing light reflection after passing through media with different refractive indices and greatly improving the light transmittance of the entire cover plate. Furthermore, the optical layer 5 not only improves the light transmittance of the cover plate but also improves the uniformity of light, providing a more stable and uniform lighting environment for the entire photovoltaic module 4, thereby improving the working performance of the photovoltaic module 4.

[0049] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A phase change energy storage type high-efficiency solar collector cover plate, characterized in that: The device includes a heat storage box and multiple heat storage plates. The heat storage plates are stacked on top of each other to form a cover plate and are disposed on the front side of the photovoltaic module. The heat storage box is disposed on the back side of the photovoltaic module. The heat storage box is connected to the heat storage plates through a heat transfer structure, which is adapted to unidirectionally transfer the heat absorbed by the heat transfer plates to the heat storage box.

2. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 1, characterized in that: The heat transfer structure includes multiple flow channels, a phase change working fluid, and a heat storage working fluid. One end of each flow channel is connected to the upper end of the heat storage plate, and the other end passes through the heat storage box and is connected to the lower end of the heat storage plate. The flow channel is unidirectional from top to bottom. Multiple heat storage plates correspond to different flow channels, and a single heat storage plate is connected to multiple spaced flow channels in a horizontal direction. The phase change working fluid is disposed inside the heat storage plate. The phase change working fluid absorbs heat from the photovoltaic module and changes phase to gas, thereby heating the heat storage working fluid located in the heat storage box through the flow channels. The phase change working fluid is adapted to change phase to liquid after heating and flow back into the heat storage plate.

3. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 2, characterized in that: The phase change temperature of the phase change working medium in each of the thermal storage plates is different, with the phase change temperature of the outer phase change working medium being lower than that of the inner phase change working medium.

4. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 3, characterized in that: The thickness of each of the heat storage plates is different, with the outer heat storage plate being less thick than the inner heat storage plate.

5. The phase change energy storage type high-efficiency solar collector cover plate as described in any one of claims 1-4, characterized in that: The number of heat storage plates is 2-4.

6. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 2, characterized in that: The heat storage medium is a fluid.

7. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 2, characterized in that: The cross-sectional shape of the flow channel is circular or elliptical.

8. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 7, characterized in that: The volume of the flow channel corresponding to a single heat storage plate is 10%-15% of the volume of the heat storage plate.

9. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 2, characterized in that: A one-way valve is provided at the connection position between the flow channel pipe and the lower end of the heat storage plate.

10. The phase change energy storage type high-efficiency solar collector cover plate as described in claim 1, characterized in that: An optical layer for reducing light reflection is provided between two adjacent heat storage plates.

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