Photovoltaic photo-thermal pure water co-production system with interface evaporative cooling coupled with radiation refrigeration

Abstract

The invention discloses a photovoltaic photo-thermal pure water co-production system with interface evaporative cooling coupled with radiation refrigeration, and relates to the field of photovoltaic power generation, and the system comprises a photovoltaic power generation device which is used for receiving solar radiation and generating electric energy; the radiation refrigeration device is arranged in the adjacent area of the photovoltaic cell panel and used for condensing water vapor, the photovoltaic cooling assembly is connected with the top end and the bottom end of the photovoltaic power generation device to form a first cooling loop, and the radiation refrigeration circulation assembly is connected with the radiation refrigeration device. The radiation refrigeration cycle assembly is connected with the top end and the bottom end of the photovoltaic power generation device and the top end and the bottom end of the radiation refrigeration device to form a second cooling loop. And double-loop coupling is effectively formed, the cooling efficiency and the water resource circulation efficiency are improved, and an integrated solution with higher energy efficiency and resource self-sustaining capability is provided for a photovoltaic power generation system under extreme conditions of drought, no network and the like.

Description

Technical Field

[0001] This specification relates to the field of photovoltaic power generation, and more specifically, the present application relates to a photovoltaic, thermal and pure water cogeneration system with interface evaporative cooling coupled with radiative refrigeration. Background Art

[0002] Photovoltaic panels generate a significant amount of waste heat during power generation, significantly increasing their operating temperature. This in turn reduces power generation efficiency and accelerates material aging. To reduce panel temperatures, existing technologies have proposed active cooling (such as forced water cooling and air cooling) and passive cooling (such as phase change materials and radiative cooling coatings).

[0003] However, active cooling systems consume a lot of energy and water, making them unsuitable for drought-prone or off-grid environments. Passive cooling, while energy-free, has limited cooling effectiveness and cannot effectively recover evaporated water. Some hydrogel cooling technologies that combine evaporation and moisture absorption, while innovative, suffer from significant water vapor loss, dependence on ambient humidity, and high hydrogel costs, making long-term autonomous operation difficult.

[0004] Existing technologies are unable to simultaneously achieve efficient photovoltaic cooling, improved power generation performance, and freshwater resource recovery with low energy and water consumption. This is particularly true in droughts and extreme environments, where significant application bottlenecks remain. Therefore, a photovoltaic-thermal water cogeneration system combining interfacial evaporative cooling and radiative cooling is urgently needed to address some of these challenges. Summary of the Invention

[0005] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. The Summary of the Invention of this application is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] In the first aspect, the present application proposes a photovoltaic-thermal water cogeneration system with interfacial evaporative cooling coupled with radiative cooling, comprising: Photovoltaic power generation devices, which are used to receive solar radiation and generate electricity; A radiation cooling device is provided in the vicinity of the photovoltaic panel, and is used to condense water vapor. Photovoltaic cooling components, the photovoltaic cooling components are respectively connected to the top and bottom ends of the photovoltaic power generation device to form a first cooling circuit, A radiation refrigeration cycle component is connected to the top and bottom ends of the photovoltaic power generation device and the top and bottom ends of the radiation refrigeration device to form a second cooling circuit.

[0007] In a feasible embodiment, the photovoltaic power generation device includes a photovoltaic cell panel and an interface evaporation layer. The photovoltaic panels are used to receive solar radiation and generate electricity; The interface evaporation layer is attached to the back of the photovoltaic cell panel. The interface evaporation layer is used to absorb photovoltaic waste heat and drive the evaporation of the water film.

[0008] In a feasible embodiment, the photovoltaic power generation device includes a photovoltaic panel and a radiator. The photovoltaic panels are used to receive solar radiation and generate electricity; The radiator comprises a fin-type radiator and an active fan, and the radiator is attached to the back of the photovoltaic panel.

[0009] In a feasible embodiment, the interface evaporation layer is composed of a high thermal conductivity interface material and a porous hydrophilic material, and a capillary channel is provided inside the interface evaporation layer.

[0010] In a feasible embodiment, the photovoltaic cooling assembly includes an upper water storage tank, a lower water storage tank and a water pump. The upper water storage tank is connected to the top of the interface evaporation layer through a pipeline to provide evaporation water for the interface evaporation layer; The lower water storage tank is connected to the bottom end of the interface evaporation layer through a pipeline and is used to collect the unevaporated water and condensed recovered water in the interface evaporation layer; The water pump is connected to the upper water tank and the lower water tank through a pipeline, and is used to pump water in the lower water tank back to the upper water tank to form the first cooling circuit.

[0011] In a feasible embodiment, the photovoltaic power generation device further includes a guide trough and a pure water tank, wherein the guide trough is used to guide the liquid water obtained by condensing the water vapor to the pure water tank, and the pure water tank is connected to the photovoltaic power generation device and the radiation refrigeration device.

[0012] In a feasible implementation, it further includes: Automatic opening and closing covers are arranged at the upper and lower ends of the photovoltaic power generation device and / or the radiation cooling device.

[0013] In a feasible embodiment, the system further includes a light intensity sensor, which is connected to the automatic opening and closing cover and controls the opening degree of the automatic opening and closing cover.

[0014] In a feasible embodiment, the surface of the radiation cooling device is coated with a silicon dioxide-polymer composite infrared radiation coating.

[0015] In a feasible implementation manner, the photovoltaic power generation device and the radiation cooling device are connected to the same supporting structure via a detachable connection device.

[0016] In summary, this embodiment utilizes a dual cooling circuit structure consisting of a photovoltaic cooling module and a radiant refrigeration cycle module to achieve active evaporative cooling of PV module waste heat and passive recovery of condensed water vapor. The first cooling circuit closely adheres to the PV module, absorbing heat and dissipating it through evaporation. The second cooling circuit transports the water vapor to the surface of the radiant refrigeration device for condensation. This effectively forms a "heat source-condenser" dual-loop coupling, improving both cooling efficiency and water recycling efficiency. This provides an integrated solution for achieving higher energy efficiency and resource self-sustainability for PV power generation systems operating in extreme conditions such as drought and off-grid environments.

[0017] Other advantages, objectives and features of the present application will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present description. The same reference symbols are used throughout the drawings to represent the same components. In the drawings: Figure 1 A schematic structural diagram of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 2 A schematic diagram of the principle of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 3 Another schematic diagram of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 4 A schematic diagram of a photovoltaic power generation device and its connected components provided in an embodiment of the present application; Figure 5 A schematic diagram of the principles of a radiant cooling device and its connected components provided in an embodiment of the present application; Figure 6 A schematic diagram showing a comparison of infrared photography during actual outdoor operation during daytime for the system of the present invention and the system of the related art provided in an embodiment of the present application; Figures 1 to 5 The corresponding relationship between the reference numerals and the names of the drawings is as follows: 101 photovoltaic power generation device, 102 radiation cooling device, 103 photovoltaic cooling assembly, 104 radiation cooling cycle assembly; 1011 photovoltaic cell panel, 1012 interface evaporation layer; 1031 upper water storage tank, 1032 lower water storage tank, 1033 water pump; 1041 pure water tank, 105 automatic opening and closing cover, 106 detachable connecting device. DETAILED DESCRIPTION

[0019] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. 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 clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments.

[0020] Photovoltaic power generation, as an important form of clean and renewable energy, has been widely used in various energy systems. However, due to conversion efficiency limitations, only approximately 15% to 20% of the solar radiation received by photovoltaic modules is converted into electricity. The majority of the remaining energy accumulates as waste heat on the back of the panels, significantly increasing the module's operating temperature (typically 10 to 40°C above ambient temperature). This temperature increase reduces the output power of photovoltaic modules, with a typical temperature coefficient of approximately 4% to 6% decrease in power generation efficiency for every 10°C increase. Furthermore, prolonged exposure to high temperatures can cause problems such as aging of packaging materials and solder fatigue, seriously impacting the stability and service life of photovoltaic systems.

[0021] To address the issue of rising photovoltaic temperatures, existing technologies have proposed a variety of cooling solutions, primarily active and passive. Active cooling, such as forced water cooling or air cooling systems, removes heat through external devices such as water pumps or fans, typically reducing component temperature by 10-20°C. However, these solutions have significant drawbacks: First, the system relies on high-power electric equipment, consuming as much as 5-20 W / m² per unit area; second, a continuous water supply is required to maintain the cooling process, consuming as much as 10-50 L / m². 2 ·h, which significantly limits its feasibility and sustainability in arid areas or off-grid scenarios.

[0022] Passive cooling technology does not require external energy consumption and relies on the physical properties of the material itself to dissipate heat. For example, the phase change material (PCM) cooling solution absorbs heat to achieve phase change absorption, but its thermal conductivity is low, which easily causes local heat accumulation and response hysteresis, and the cooling rate is limited. Another type of radiative cooling coating technology uses the 8-13μm atmospheric window band to release heat into outer space in the form of infrared radiation. Although it can have a certain cooling effect at night or on cloudy days, during the day when the sun is strong, the solar radiation heat it absorbs often exceeds its radiation capacity, resulting in limited cooling effect. In addition, existing radiative cooling and evaporative cooling technologies have not effectively solved the problem of water vapor recovery. After evaporation, the water vapor is directly lost, and the recycling of water resources cannot be achieved.

[0023] Some technologies attempt to combine evaporative cooling with photovoltaic cooling, such as using hydrogel materials to absorb air humidity and dissipate heat through evaporation. While these technologies offer a certain degree of self-watering and evaporation capabilities, their open structure makes water vapor difficult to recycle, and the system lacks a closed condensation mechanism, hindering the goal of co-generating freshwater. Furthermore, the hydrogel material itself is expensive and prone to aging, and its moisture absorption capacity is limited by air humidity, making it difficult to achieve stable operation in arid climates.

[0024] Existing photovoltaic cooling technology is difficult to simultaneously meet the comprehensive needs of efficient cooling, increased power output and water resource recovery in terms of key indicators such as low water consumption, low energy consumption and continuous operation. Especially in resource-constrained or extreme climate areas, there is an urgent need for a new photovoltaic thermal management system that integrates cooling, water supply and energy efficiency.

[0025] See also Figure 1-Figure 5 , Figure 1 A schematic structural diagram of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 2 A schematic diagram of the principle of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 3 Another schematic diagram of a photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling provided in an embodiment of the present application; Figure 4 A schematic diagram of a photovoltaic power generation device and its connected components provided in an embodiment of the present application; Figure 5 A schematic diagram of the principles of a radiative cooling device and its connected components provided in an embodiment of the present application. The system may specifically include: Photovoltaic power generation device 101, for receiving solar radiation and generating electrical energy; The radiation cooling device 102 is provided in the vicinity of the photovoltaic power generation device 101. The radiation cooling device 102 is used to condense water vapor. The photovoltaic cooling assembly 103 is connected to the top and bottom of the photovoltaic power generation device 101 to form a first cooling circuit. The radiation refrigeration cycle component 104 is connected to the top and bottom of the photovoltaic power generation device 101 and the top and bottom of the radiation refrigeration device 102 to form a second cooling circuit.

[0026] For example, in this embodiment, a dual-circuit coupled cooling system for cooling photovoltaic modules and co-generating water resources is proposed, specifically comprising a photovoltaic power generation device 101, a radiant refrigeration device 102, a photovoltaic cooling component 103, and a radiant refrigeration cycle component 104. The structures and functional relationships of the various components are as follows: The photovoltaic power generation device 101 is the core energy conversion module of this system. Its primary function is to receive solar radiation and convert it into electrical energy. This process also generates a significant amount of waste heat. If this waste heat is not promptly and effectively removed, it will lead to increased component temperature, reduced power generation efficiency, and shortened service life. Therefore, a corresponding thermal management system is required to improve overall performance.

[0027] The photovoltaic cooling assembly 103 is used to directly cool the photovoltaic power generation device 101. Its structure is located between the top and bottom ends of the photovoltaic power generation device 101, forming a first cooling circuit. In this embodiment, this cooling circuit typically includes an interfacial evaporative cooling structure, which is internally composed of capillary channels, porous hydrophilic materials, and a water film heat transfer layer. This effectively absorbs waste heat from the back of the photovoltaic power generation device 101 and evaporates the water to achieve cooling.

[0028] Radiative cooling device 102 is installed adjacent to photovoltaic power generation device 101 as an independent low-temperature condensation module. By coating the surface with a high-infrared emissivity material (such as a silica-polymer composite film), it efficiently radiates heat into outer space within the 8–13 μm infrared band. This creates a condensation surface below ambient temperature, effectively condensing water vapor and producing pure condensed water.

[0029] To efficiently recover evaporated water vapor and form a complete closed-loop system, the system also features a radiant refrigeration cycle assembly 104. This assembly connects the top and bottom ends of the photovoltaic power generation device 101 and the top and bottom ends of the radiant cooling device 102, forming a second cooling circuit. During operation, water vapor generated by the evaporative cooling assembly is introduced into the radiant cooling device 102 through a flow-guiding structure. Condensation droplets form on the surface of the radiant cooling device and are drawn into the lower water storage area through gravity or capillary action, thus achieving water resource recovery and utilization.

[0030] In summary, this embodiment achieves active evaporative cooling of PV panel waste heat and passive recovery of condensed water vapor by constructing a dual cooling circuit structure consisting of a photovoltaic cooling assembly and a radiant refrigeration cycle assembly 104. The first cooling circuit closely adheres to the PV panel for heat absorption and evaporative heat dissipation, while the second cooling circuit transports water vapor to the surface of the radiant refrigeration device for condensation. This effectively forms a "heat source-condenser" dual-loop coupling, improving cooling efficiency and water resource recycling efficiency. This provides an integrated solution with higher energy efficiency and resource self-sustainability for PV power generation systems operating in extreme conditions such as drought and off-grid conditions.

[0031] In a feasible embodiment, the photovoltaic power generation device 101 includes a photovoltaic panel 1011 and an interface evaporation layer 1012. The photovoltaic panels are used to receive solar radiation and generate electricity; The interface evaporation layer is attached to the back of the photovoltaic cell panel. The interface evaporation layer is used to absorb photovoltaic waste heat and drive the evaporation of the water film.

[0032] Illustratively, the photovoltaic power generation device 101 further includes a photovoltaic panel 1011 and an interface evaporation layer 1012 , which together form a tightly coupled thermoelectric synergistic structure, which not only realizes the photoelectric conversion function of solar energy, but also has efficient waste heat management and water evaporation recovery functions.

[0033] Specifically, photovoltaic panels 101, the main component of the device, face the sun. Their primary function is to receive solar radiation and convert some of the energy into electricity through the photoelectric effect. However, during this conversion process, typically only 15% to 20% of the irradiated energy is converted into electricity. The majority of the remaining energy is converted into heat and accumulates on the back of the panel, causing the panel to heat up, affecting power generation efficiency and service life.

[0034] To effectively utilize this "waste photovoltaic heat," the system incorporates an interfacial evaporation layer on the backside of the photovoltaic panels. This evaporation layer is typically composed of a highly thermally conductive interface material (such as graphite film or aluminum-based composites) and a porous hydrophilic material. Its design aims to rapidly transfer waste heat generated by the photovoltaic panels to the water film interface, promoting water evaporation. The evaporation layer incorporates a capillary channel structure connected to the upper water storage tank. This capillary action continuously draws water from the water source, forming a uniform, thin film on the surface.

[0035] In actual operation, solar radiation is converted into electricity by photovoltaic panels, while the heat generated is promptly absorbed by the interfacial evaporation layer, driving the continuous evaporation of the water film. The latent heat released during the evaporation process effectively removes heat from the back of the cell, cooling the module and improving power generation efficiency. Simultaneously, the generated water vapor can be further directed to a radiative cooling device for condensation and collection through system design, ultimately achieving a triple coupling of thermal energy utilization, electrical energy output, and water resource recovery.

[0036] In summary, this implementation method integrates an interfacial evaporation layer on the back of the photovoltaic panel, fully utilizing the waste heat generated during the photovoltaic conversion process to achieve the synergistic conversion of electricity, heat, and water. This not only improves the operating efficiency of the photovoltaic module, but also provides a clean cooling and freshwater co-production solution for arid and resource-constrained areas without the need for additional energy consumption.

[0037] In another feasible embodiment, the photovoltaic power generation device 101 includes a photovoltaic panel 1011 and a radiator. The photovoltaic panels 1011 are used to receive solar radiation and generate electricity; The radiator comprises a fin-type radiator and an active fan, and the radiator is attached to the back of the photovoltaic panel.

[0038] For example, a heat sink structure can be integrated on the back of the photovoltaic panel 1011. This heat sink includes a finned heat sink and an active fan. The finned heat sink is made of a highly thermally conductive metal material (such as aluminum alloy or copper) and features multiple rows of evenly distributed fins to increase the heat dissipation surface area and enhance the efficiency of natural convection and radiation heat dissipation. The heat sink is attached to the back of the photovoltaic panel 1011 via a thermally conductive base, allowing heat to be quickly transferred from the panel to the heat sink structure.

[0039] To further enhance heat dissipation, the radiator is equipped with an active fan, located between or outside the fins, to accelerate heat transfer by forcing air. Powered by either the photovoltaic panels themselves or an external energy storage module, the active fan automatically activates in response to strong sunlight or abnormally high temperatures, enabling dynamic temperature control.

[0040] During actual operation, when light intensity increases and the temperature of the photovoltaic panels rises, the heat sink kicks in. The fin structure distributes heat over a larger surface area, effectively exchanging heat with the air. The active fan accelerates air flow, quickly dissipating accumulated heat, minimizing backsheet temperature and maintaining the panels within the temperature control range for efficient power generation.

[0041] It should be noted that the use of this type of photovoltaic power generation device will slightly increase energy consumption, and the control strategy can be simplified to a manual water supply valve, but at the expense of autonomous operation capabilities in arid environments.

[0042] In summary, this implementation effectively improves the heat dissipation efficiency of the components during operation by setting a heat dissipation structure composed of a fin-type heat sink and an active fan on the back of the photovoltaic panel, without requiring large-scale changes to the existing component packaging structure. It also enhances the system's adaptability to extreme climatic conditions such as high temperature and high radiation, and provides important guarantees for improving the overall output power and operational reliability of the photovoltaic system.

[0043] In a feasible embodiment, the interface evaporation layer is composed of a high thermal conductivity interface material and a porous hydrophilic material, and a capillary channel is provided inside the interface evaporation layer.

[0044] Illustratively, the interface evaporation layer is composed of a composite of a high thermal conductivity interface material and a porous hydrophilic material, and is provided with capillary channels inside for efficiently conducting heat and maintaining a continuous supply of water, thereby realizing active evaporative cooling function on the back of the photovoltaic module.

[0045] Specifically, a high-thermal-conductivity interface material, serving as the heat-conducting framework for the interface evaporation layer, can be selected from materials with excellent thermal conductivity, including but not limited to graphene film, graphite sheets, copper-based composite thermally conductive materials, or aluminum alloy thermally conductive layers. This material is applied to the back of the photovoltaic panel, achieving efficient heat dissipation through a close fit. This material can quickly capture and conduct the large amount of waste heat generated by the photovoltaic module during power generation, providing a stable heat source input for the evaporation process.

[0046] Porous hydrophilic materials are applied to the outer layer of the thermal interface material or embedded within it. Their structures feature micro- and nanoscale pore networks, enabling excellent water absorption and evaporation. These materials include, but are not limited to, modified cellulose, hydrogel-coated materials, ceramic foams, and polyvinyl alcohol composite structures. These materials not only store water and expand the surface area of the water film, but also stably maintain water saturation at the evaporation interface, ensuring continuous evaporation.

[0047] The interfacial evaporation layer is constructed with capillary channels connected to the upper water storage tank. These channels continuously draw water to the evaporation surface through capillary action, eliminating the need for an additional water supply pump or pressure system. The capillary channels are typically arranged in a grid or radial pattern to ensure even distribution of water across the entire evaporation layer, preventing localized drying or uneven evaporation efficiency.

[0048] During actual operation, photovoltaic panels exposed to solar energy convert light into electricity while releasing a significant amount of waste heat on their backside. This heat is rapidly transferred through the highly thermally conductive interface material to the hydrophilic material on the surface of the evaporation layer, where it rapidly evaporates in the water film formed on the surface. This water absorbs heat and evaporates, removing the heat and thus actively cooling the photovoltaic panels. Simultaneously, the water vapor generated by evaporation is captured and condensed by the system's radiant cooling device, ultimately leading to a closed-loop system that directs it into a water tank.

[0049] In summary, this implementation method achieves efficient recovery and conversion of waste heat from the back of photovoltaic modules by constructing an interface evaporation layer composed of a high thermal conductivity interface material and a porous hydrophilic material, supplemented by capillary channels. It not only has good thermal conductivity, but also ensures a continuous supply of water and stable evaporation, providing key support for the system to achieve low energy consumption, self-driven cooling and water recycling.

[0050] In a feasible embodiment, the photovoltaic cooling assembly 103 includes an upper water storage tank 1031, a lower water storage tank 1032 and a water pump 1033. The upper water storage tank 1031 is connected to the top of the interface evaporation layer 1012 via a pipeline, and is used to provide evaporation water for the interface evaporation layer 1012; The lower water storage tank 1032 is connected to the bottom of the interface evaporation layer 1012 through a pipeline, and is used to collect the unevaporated water and condensed recovered water in the interface evaporation layer; The water pump 1033 is connected to the upper water tank 1031 and the lower water tank 1032 via a pipeline, and is used to pump water in the lower water tank 1032 back to the upper water tank 1031 to form the first cooling circuit.

[0051] Exemplarily, the photovoltaic cooling assembly 103 includes an upper water storage tank 1031 , a lower water storage tank 1032 and a water pump 1033 . These three parts constitute a closed water circulation system through pipelines, forming a first cooling circuit for interface evaporative cooling.

[0052] Specifically, upper water tank 1031 is installed above interface evaporation layer 1012. It primarily stores cooling water and provides a continuous, stable water source for the evaporation layer through gravity or capillary action. In this embodiment, upper water tank 1031 is connected to the top of interface evaporation layer 1012 via a capillary tube or capillary. This connection requires no pressurizing device. Instead, the capillary channel automatically draws water to the evaporation surface, forming a uniform, thin film of water that provides the foundation for evaporative cooling.

[0053] The interface evaporation layer 1012 is located on the back of the photovoltaic panel. Its bottom is connected to a diversion channel or drainage channel, which is connected to the lower water storage tank 1032. It is used to collect residual water that is not fully vaporized during the evaporation process, as well as condensed water recovered by the system's condensation module (such as a radiant cooling device). The lower water storage tank 1032 serves as the system's return point, ensuring that all unused or recycled water recirculates, avoiding water waste.

[0054] To maintain the continuous operation of this closed-loop circulation system, a water pump 1033 is installed between the upper water tank 1031 and the lower water tank 1032. It uses a pipeline to transfer water recovered from the lower water tank 1032 back to the upper water tank 1031, thus achieving water recycling. This water pump can be a miniature, low-power device that can be powered by photovoltaic panels. It has stable operation and low energy consumption, making it suitable for off-grid scenarios.

[0055] During system operation, the photovoltaic panels generate electricity from solar radiation while also accumulating heat on their backsides. Upper water tank 1031 continuously supplies water to the evaporation layer at the interface, where a water film forms and continuously evaporates under the high temperature, achieving active cooling. Residual water from the evaporation process and subsequent condensation are collected in lower water tank 1032 and pumped back to upper water tank 1031 via pump 1033, forming a complete and efficient closed-loop evaporative cooling system.

[0056] In summary, this implementation method forms a water circulation path by setting up upper and lower water storage tanks and water pumps, thereby achieving stable water supply to the interface evaporation layer and condensed water recovery, so that the photovoltaic cooling component has self-water supply and self-recovery functions, effectively improving the system's sustainable operation capability under drought and no external water source conditions, and enhancing cooling efficiency and water resource utilization.

[0057] In a feasible embodiment, the photovoltaic power generation device 101 further includes a guide trough and a pure water tank 104. The guide trough is used to guide the liquid water obtained by condensing the water vapor to the pure water tank 104. The pure water tank 104 is connected to the photovoltaic power generation device and the radiation cooling device.

[0058] Exemplarily, the photovoltaic power generation device 101 further includes a guide trough and a pure water tank 104, whose main function is to collect and store condensed water generated by evaporative cooling and radiant cooling in an orderly manner during system operation, thereby achieving efficient recovery of water resources and co-production of pure water.

[0059] Specifically, during daytime operation, the interfacial evaporation layer absorbs waste heat from the back of the photovoltaic panels, driving the evaporation of a water film and generating a large amount of water vapor. This water vapor rises to the condensation surface of the radiant cooling device 102, where it rapidly cools due to the temperature difference and condenses into liquid water droplets. To prevent the random loss or leakage of this precious condensed water, the system is designed with a diversion trough structure. This trough is typically made of a lightweight, corrosion-resistant material (such as polypropylene, aluminum alloy, or flexible silicone) and is located at a critical location between the radiant cooling device and the evaporation layer.

[0060] The diversion trough features a specific inclination angle or built-in capillary guide structure, which collects and directs the condensed water to the system's designated recovery location, namely, pure water tank 104. This pure water tank 104 is typically installed below or to the side of the photovoltaic power generation device. Its casing is well-sealed and features structural optimizations such as dustproofing, sun protection, and heat insulation. Optional internal filters or mineralization modules ensure that the collected condensed water can meet practical needs such as domestic use or agricultural irrigation.

[0061] It's worth noting that pure water tank 104 is not only connected to photovoltaic power generation device 101, but also maintains a fluid connection with radiant cooling device 102, allowing it to receive liquid water from multiple condensation surfaces (such as the top of the radiant panel and the condensation chamber on the evaporation surface). Through unified flow management, all water generated through evaporation and condensation can flow into the pure water tank for centralized storage, providing a stable water source for subsequent use (such as water quality utilization, irrigation supply, or recycling).

[0062] During system operation, the evaporation layer continuously produces water vapor, the radiant condensation surface continuously recovers water, the diversion trough provides pressure-free guidance, and the pure water tank achieves fixed-point storage. This process can be completed without additional power supply, effectively enhancing the system's self-sustaining operation capabilities in arid, remote, or unmanned areas.

[0063] In summary, this embodiment integrates the diversion trough and the pure water tank 104 in the photovoltaic power generation system to construct a complete water circulation chain of "evaporation-condensation-drainage-storage", achieving a high degree of integration of evaporative cooling and fresh water recovery, which not only improves the operating efficiency of the photovoltaic modules, but also provides a safe, clean, and low-energy new solution for water resource acquisition.

[0064] In a feasible implementation, it further includes: Automatic opening and closing covers are arranged at the upper and lower ends of the photovoltaic power generation device and / or the radiation cooling device.

[0065] In a feasible embodiment, the system further includes a light intensity sensor, which is connected to the automatic opening and closing cover and controls the opening degree of the automatic opening and closing cover.

[0066] For example, in order to further improve the operational adaptability and energy efficiency control capability of the system under different environmental conditions, the system also includes an automatic opening and closing cover, which is arranged at the upper and lower ends of the photovoltaic power generation device and / or the radiant refrigeration device, and is used to dynamically adjust the open or closed state of the system under different lighting conditions, thereby optimizing the evaporation, condensation and water resource recovery process.

[0067] Specifically, the automatically opening and closing cover is connected to the photovoltaic module frame or cooling panel edge via hinges, slides, or flexible connections, allowing it to open and close vertically or along a rotational axis. The cover itself can be made of high-strength, lightweight materials such as polycarbonate, aluminum-coated film, or composite insulation structures, providing excellent light-blocking and sealing properties.

[0068] Under strong sunlight during the day, the system absorbs heat from the evaporation layer, driving the water film to evaporate. The vapor rises within the enclosed space to the low-temperature surface where it condenses and is recovered. At this point, the automatic opening and closing cover closes, effectively isolating the system from external hot air disturbances and maintaining the saturation and stability of the internal water vapor environment, thereby improving water vapor condensation efficiency and reducing evaporation losses.

[0069] At night or under low radiation conditions, in order to enhance the natural adsorption and condensation of moisture in the air, the system will automatically open the cover, exposing the surface of the porous hydrophilic material to the atmospheric environment, allowing it to fully absorb water vapor in the air. At the same time, the surface of the radiation refrigeration device is used to further condense the air humidity, achieving two-way hydration.

[0070] To achieve this automatic control of the cover's status, the system also incorporates a light intensity sensor, which monitors external solar radiation levels in real time and transmits this information to the cover control module. This sensor, typically located at the top of the system or on the surface of the photovoltaic panels, exhibits high sensitivity and adaptability to environmental conditions. Based on a set light threshold, when light intensity exceeds an upper limit (e.g., 400 W / m²), the control module closes the cover. When light intensity falls below a lower limit (e.g., 100 W / m²) or when the system enters night mode, the cover automatically opens.

[0071] The entire control system can be driven by a low-power microcontroller and powered by a photovoltaic power source or a small battery. It has good intelligent responsiveness and off-grid operation capabilities.

[0072] In summary, this embodiment integrates automatic opening and closing covers on the photovoltaic power generation and condensing modules, and combines them with light intensity sensors to form a dynamic control mechanism. This not only improves the system's water vapor regulation efficiency under different day and night environments, but also enhances the intelligent adjustment capability of the entire evaporation-condensation-humidification link, realizing an environmentally adaptive upgrade of the photovoltaic cooling and water resource recovery system.

[0073] In a feasible embodiment, the surface of the radiation cooling device is coated with a silicon dioxide-polymer composite infrared radiation coating.

[0074] For example, in a feasible embodiment, in order to improve the efficiency of radiative cooling, the surface of the above-mentioned radiative cooling device is coated with a silica-polymer composite infrared radiation coating. The coating has high infrared emissivity and good spectral selectivity, which can effectively realize passive radiative heat dissipation in environments with strong sunlight and significant temperature differences between day and night, and assist in water vapor condensation. The radiation coating is composed of a composite of silica particles and functional polymers, and can be uniformly applied to the metal or composite substrate surface of the radiative cooling device by sol-gel method, spin coating, spraying or hot pressing. During system operation, when the sunlight is strong during the day, the infrared coating actively releases the heat on the surface of the system into outer space in the form of radiation, while absorbing very little heat itself, which can effectively offset the heat imbalance between radiation and solar energy. When the ambient temperature drops at night, the coating still maintains a high radiation capacity, making the radiative cooling device a low-temperature sink for condensing water vapor and air moisture, maintaining the continuity of fresh water collection.

[0075] In summary, this implementation significantly improves the heat dissipation and condensation capabilities of the system in a passive state by coating the surface of the radiant cooling device with a silica-polymer composite infrared radiation coating, providing key material support for photovoltaic cooling and fresh water recovery, and effectively enhancing the energy efficiency and stability of the entire system under different climatic conditions.

[0076] In a feasible implementation, the photovoltaic power generation device 101 and the radiation cooling device 102 are connected to the same supporting structure via a detachable connection device 105 .

[0077] Illustratively, the photovoltaic power generation device and the radiation cooling device are installed on the same supporting structure via a detachable connecting device, forming an integrated device with a stable structure, coordinated functions, and convenient installation.

[0078] Specifically, the system utilizes a uniformly designed support structure as its installation foundation. This structure, typically constructed of aluminum alloy or stainless steel, offers excellent strength, corrosion resistance, and lightweight properties, making it suitable for installation in various scenarios, including rooftops, ground surfaces, and mobile platforms. The support structure is pre-configured with multiple sets of standard mounting notches or holes for mounting the photovoltaic power generation unit and the radiant cooling unit, respectively.

[0079] To achieve compact docking and rapid assembly between the two, the system incorporates removable connection devices, including but not limited to bolt-and-slot fittings, snap-fit mechanisms, latch-type joints, or guide rail and slot structures. During actual system operation, while the photovoltaic power generation device and radiant cooling device have distinct functions, they form a stable structural unit through unified support and standardized interfaces. This not only enables data coordination between modules (such as temperature control signals and opening and closing controls), but also allows for rapid replacement or upgrades in the event of a failure or when functionality expansion is required.

[0080] Furthermore, the detachable connection method provides excellent support for system iteration in different scenarios. For example, during initial deployment, only PV panels can be installed, and then radiant cooling modules can be integrated according to water resource needs. This allows for rapid expansion of functions through the connection device without having to completely restructure the system.

[0081] In summary, this embodiment uses a detachable connection device to fix the photovoltaic power generation device and the radiant cooling device to the same support structure, which not only simplifies the installation process and improves the consistency and coordination efficiency between modules, but also enhances the system's maintainability, scalability and on-site adaptability, reflecting the structural flexibility and industrial practical value for engineering applications.

[0082] Figure 6 The present application provides an embodiment of the system of the present invention and a schematic diagram of infrared camera comparison during actual outdoor operation during the daytime in the system of the related art. Under the same environmental conditions, the surface temperature of the pure photovoltaic panel in the related art is up to 42.2 degrees Celsius, while the temperature of the photovoltaic panel using this solution is up to 25.7 degrees Celsius.

[0083] In the traditional photovoltaic modules without active or passive cooling structure, a large amount of radiation heat accumulates on the back during the photoelectric conversion process, causing the panel temperature to rise rapidly. Figure 6 Thermal imaging reveals distinct hotspots on the surface of pure photovoltaic panels, with uneven overall temperature distribution concentrated between 35°C and 42.2°C. This high temperature directly reduces module conversion efficiency and accelerates material aging, especially in systems operating in high-irradiance and high-temperature environments, where temperature control issues are particularly acute.

[0084] In contrast, the system of the present invention (experimental group) integrates a highly thermally conductive interface evaporation layer and a porous hydrophilic membrane structure on the back of the photovoltaic panel, forming a continuous evaporative cooling channel. A radiative cooling device is also installed on the top, radiating heat into outer space through the infrared window band. Infrared images show that under the same test period and environmental conditions, the surface temperature of the photovoltaic modules in this system is significantly lower, with a maximum temperature of only 25.7°C. The overall heat distribution is uniform, with no obvious hot spots, and the surface temperature is approximately 16.5°C lower than that of traditional modules.

[0085] This cooling effect comes from the synergy of two key mechanisms: 1. Evaporative cooling mechanism: After the photovoltaic waste heat is absorbed by the evaporation layer, it drives the water film to evaporate, releasing the evaporation latent heat to take away the heat and suppress the temperature rise; 2. Radiative cooling mechanism: The temperature of the condensation surface is continuously lower than the ambient temperature, and the heat is effectively released to the outer atmosphere and even space through the radiation path.

[0086] The combination of these two forms a closed-loop path of "heat absorption → evaporation → condensation → heat dissipation," enabling continuous operation during high daytime temperatures, effectively mitigating the temperature rise of the photovoltaic panels. Based on the typical photovoltaic temperature coefficient (approximately -0.45% / °C), a temperature reduction of just 16.5°C can result in an approximately 7.4% increase in power generation efficiency.

[0087] In summary, Figure 6 The infrared comparison chart not only clearly demonstrates the significant improvement in temperature control capability of the present invention, but also indirectly illustrates that the system has practical engineering application value in improving photovoltaic efficiency, extending equipment life, and reducing operational risks. It is particularly suitable for the deployment of photovoltaic power stations in extreme climatic conditions such as deserts, plateaus, and high sunshine.

[0088] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A photovoltaic-thermal water cogeneration system with interface evaporative cooling coupled with radiative cooling, characterized in that: include: Photovoltaic power generation devices, which are used to receive solar radiation and generate electricity; A radiation cooling device is provided in the vicinity of the photovoltaic power generation device, and is used to condense water vapor. A photovoltaic cooling assembly is connected to the top and bottom of the photovoltaic power generation device to form a first cooling circuit. A radiation refrigeration cycle component is connected to the top and bottom ends of the photovoltaic power generation device and the top and bottom ends of the radiation refrigeration device to form a second cooling circuit.

2. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The photovoltaic power generation device includes a photovoltaic cell panel and an interface evaporation layer. The photovoltaic panels are used to receive solar radiation and generate electrical energy; The interface evaporation layer is attached to the back of the photovoltaic cell panel and is used to absorb photovoltaic waste heat and drive water film evaporation.

3. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The photovoltaic power generation device includes a photovoltaic panel and a radiator. The photovoltaic panels are used to receive solar radiation and generate electrical energy; The radiator comprises a fin-type radiator and an active fan, and the radiator is attached to the back side of the photovoltaic panel.

4. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The interface evaporation layer is composed of a high thermal conductivity interface material and a porous hydrophilic material, and a capillary channel is arranged inside the interface evaporation layer.

5. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The photovoltaic cooling assembly includes an upper water storage tank, a lower water storage tank and a water pump. The upper water storage tank is connected to the top of the interface evaporation layer through a pipeline, and is used to provide evaporation water for the interface evaporation layer; The lower water storage tank is connected to the bottom end of the interface evaporation layer through a pipeline and is used to collect the unevaporated water and condensed recovered water in the interface evaporation layer; The water pump is connected to the upper water tank and the lower water tank through a pipeline, and is used to pump water in the lower water tank back to the upper water tank to form the first cooling circuit.

6. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The photovoltaic power generation device further includes a guide trough and a pure water tank. The guide trough is used to guide the liquid water obtained by condensing the water vapor to the pure water tank. The pure water tank is connected to the photovoltaic power generation device and the radiation refrigeration device.

7. The photovoltaic-thermal-pure-water cogeneration system with interfacial evaporative cooling coupled with radiative cooling according to claim 1 further comprises: Automatic opening and closing covers are arranged at the upper and lower ends of the photovoltaic power generation device and / or the radiation cooling device.

8. The photovoltaic-thermal-pure-water cogeneration system with interface evaporative cooling coupled with radiative cooling according to claim 7 is characterized in that: The system further comprises a light intensity sensor, which is connected to the automatic opening and closing cover and controls the opening degree of the automatic opening and closing cover.

9. The photovoltaic-thermal-pure-water cogeneration system with interface evaporative cooling coupled with radiative cooling according to claim 1 is characterized in that: The surface of the radiation refrigeration device is coated with a silicon dioxide-polymer composite infrared radiation coating.

10. The photovoltaic-thermal-pure-water cogeneration system with interface evaporative cooling coupled with radiative cooling according to claim 1, characterized in that: The photovoltaic power generation device and the radiation cooling device are connected to the same supporting structure via a detachable connecting device.

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