Passive cooling system for photovoltaic panels based on automatic water absorption and evaporation cooling based on capillary action

Abstract

The present invention discloses a photovoltaic panel passive cooling system that automatically absorbs water and evaporates it for cooling based on capillary action. The system comprises: a photovoltaic panel, a photovoltaic bracket, a wicking material, a water supply assembly, a water pipe, a water storage tank, and an adjustment and fixing assembly. The photovoltaic panel is fixedly mounted via the photovoltaic bracket and can be mounted horizontally, tilted, or vertically. The ends of the water supply assembly are arranged horizontally along the two side edges of the photovoltaic panel. The wicking material is attached to the back of the photovoltaic panel, with its lower end extending into the water supply assembly. The water supply assembly is connected to the water storage tank via a water pipe. The adjustment and fixing assembly connects the water supply assembly and the photovoltaic panel, respectively, and is used to adjust the vertical position of the water supply assembly. The present invention achieves energy-saving, water-saving, efficient, and reliable photovoltaic panel cooling, thereby improving the power generation efficiency and operating life of the photovoltaic system.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic panel cooling, and in particular to a photovoltaic panel passive cooling system that automatically absorbs water and evaporates to reduce temperature based on capillary action. Background Art

[0002] The power generation efficiency of photovoltaic panels is negatively correlated with operating temperature, with the temperature coefficient of crystalline silicon photovoltaic panels ranging from -0.25% / °C to 0.5% / °C. In high-temperature environments exposed to strong radiation, the temperature of photovoltaic panels can reach 60-80°C, reducing power generation efficiency by 15-25%. This also accelerates component aging, causes heat damage, and shortens the lifespan of photovoltaic power generation. Lowering the operating temperature of photovoltaic panels is an effective way to improve photoelectric conversion efficiency and extend the lifespan of photovoltaic power generation. To address the high operating temperatures of photovoltaic panels, two types of cooling technologies have been proposed: active cooling and passive cooling. Active cooling, such as water circulation systems, is highly effective but requires external energy. Passive cooling, such as natural convection, is simple in structure but limited in effectiveness. While widely used, traditional water film cooling still suffers from high energy consumption, waste of water resources, complex maintenance, and unstable cooling. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to propose a passive cooling system for photovoltaic panels that automatically absorbs water and evaporates to cool down based on capillary action. By utilizing the capillary automatic water absorption characteristics of the wicking material, a passive cooling system is designed that automatically absorbs water and evaporates to cool down from the lower end of the back of the photovoltaic panel along the inclined surface upward. The system does not require external energy drive, and can achieve automatic water replenishment and continuous and stable evaporation and cooling on the back of the photovoltaic panel. It is particularly suitable for photovoltaic system power generation and operating temperature management in dry and hot areas, rainy areas or ice-free areas. It effectively solves the technical problems of existing cooling technologies such as high investment cost, high energy consumption, waste of water resources, and inconvenient maintenance and management, and achieves energy-saving, water-saving, efficient and reliable photovoltaic panel cooling effect, thereby improving the power generation efficiency and operating life of the photovoltaic system.

[0004] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0005] The present invention provides a photovoltaic panel passive cooling system that automatically absorbs water and evaporates to cool the panel based on capillary action, comprising: a photovoltaic panel, a photovoltaic bracket, a wicking material, a water supply assembly, a water pipe, a water storage tank, and an adjustment and fixing assembly; the photovoltaic panel is fixedly mounted by the photovoltaic bracket, and the mounting method is horizontal, inclined, or vertical; the two ends of the water supply assembly are horizontally arranged along the two side edges of the photovoltaic panel; the wicking material is attached to the back of the photovoltaic panel, and its lower end extends into the water supply assembly; the water supply assembly is connected to the water storage tank via the water pipe; the adjustment and fixing assembly is respectively connected to the water supply assembly and the photovoltaic panel, and is used to adjust the vertical state of the water supply assembly;

[0006] The water supply assembly includes a water supply trough, a submerged water rod and a float valve. The water supply trough is a rectangular structure. The two ends of the water supply trough are horizontally arranged along the two side edges of the photovoltaic panel, and the upper edge of the water supply trough abuts the side frame of the photovoltaic panel; the upper surface of the water supply trough is provided with a long strip channel in the horizontal direction and close to the photovoltaic panel for accommodating wicking material, the submerged water rod is installed in the water supply trough, the lower end of the wicking material passes through the channel into the water supply trough and is fixed to the submerged water rod; the left end of the upper surface of the water supply trough is connected to a boss, and the top surface of the boss is provided with a flip cover, the float valve is installed in the boss and connected to the water tank through a water pipe for automatic water replenishment and maintaining a constant water level.

[0007] Furthermore, the wicking material is quick-drying cloth, corduroy cloth or space cotton, and the vertical capillary water absorption height of the wicking material is not less than 150 mm.

[0008] Furthermore, the wicking material is attached to the back of the photovoltaic panel through thermal conductive silicone grease, and the thermal conductivity of the thermal conductive silicone grease is not less than 1W / (m·K).

[0009] Furthermore, when the height formed between the photovoltaic panel and the horizontal plane is greater than the vertical capillary water absorption height of the wicking material, a plurality of water supply components are distributed in a stepped manner along the installation direction of the photovoltaic panel, each section of wicking material corresponds to a water supply component, and the height formed between the effective length from the upper end to the gas-liquid interface in the water supply tank in each section of wicking material and the horizontal plane is less than or equal to the vertical capillary water absorption height of the wicking material, and the water supply components are connected in series through water pipes and share the same water storage tank.

[0010] Furthermore, the adjustment and fixing assembly includes two sticky hooks and two chains. The two sticky hooks are respectively fixed to the two ends of the water supply trough. One end of the chain is fixed to the sticky hook, and the other end is fixed to the edge of the photovoltaic panel to maintain the vertical state of the water supply trough.

[0011] Furthermore, when the installation mode is horizontal, the photovoltaic panel is parallel to the ground, and four photovoltaic brackets are respectively installed at the four corners of the photovoltaic panel;

[0012] When the installation mode is tilted, the photovoltaic panel is tilted, and the range of the tilt angle a between the photovoltaic panel and the ground is: 0°<a<90°, and four photovoltaic brackets are respectively installed at the four corners of the photovoltaic panel;

[0013] When the installation method is vertical, the photovoltaic panel is perpendicular to the ground, and two photovoltaic brackets are respectively installed on both sides of the photovoltaic panel.

[0014] Furthermore, one side of the water storage tank is connected to the water supply tank through a water pipe, and the other side is connected to the water source through a water pipe.

[0015] Furthermore, it also includes at least two control valves, which are installed on the water pipe and close to the water tank.

[0016] Furthermore, it also includes a support base and a base surface, the support base and the photovoltaic bracket are installed on the base surface, and the water tank is installed on the support base; the support base is an inverted U-shaped structure.

[0017] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0018] The present invention attaches wicking material to the back of the photovoltaic panel and uses the capillary action of the wicking material to automatically absorb water from bottom to top. Unlike conventional water flow cooling that relies on gravity from top to bottom, it avoids excessive consumption of water resources. It relies entirely on passive operation, and the system does not require external energy drive, does not rely on water pumps or electrical devices, and operates independently based on physical principles to achieve zero-energy cooling. After the moisture content of the wicking material decreases due to evaporation, it can directly absorb water from the water supply tank to keep the material on the back of the photovoltaic panel continuously moist. Through precise water level control and automatic water replenishment mechanism, the system only consumes the amount of water required for actual evaporation, significantly improving water resource utilization efficiency. It is particularly suitable for photovoltaic system power generation cooling and temperature management in dry and hot areas, rainy areas or ice-free areas. The system has few components, simple connections, and no complex mechanical parts, which reduces failure rate and maintenance costs. The water storage tank can collect and utilize non-traditional water resources such as rainwater, gray water, and air conditioning condensate. It is suitable for various types of crystalline silicon photovoltaic systems, and the design parameters can be flexibly adjusted according to different installation scenarios and photovoltaic panel sizes. The system can effectively reduce the photovoltaic operating temperature and improve the power generation efficiency of photovoltaic panels. It has low investment costs, is very convenient for subsequent operation and maintenance, and has low resource consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic diagram of the passive cooling system for tilted (or horizontal) mounted photovoltaic panels provided by the present invention.

[0021] Figure 2 This is a schematic diagram of the passive cooling system for vertically mounted photovoltaic panels provided by the present invention.

[0022] Figure 3 It is a schematic diagram of the installation of the water supply tank, float valve and wicking material provided by the present invention.

[0023] Figure 4It is a schematic elevation view of a state provided by the present invention in which the wicking material evaporates and becomes dry, the water supply tank is in the state of replenishing water, and the float valve is open.

[0024] Figure 5 It is a schematic elevation view of a state provided by the present invention in which the wicking material is saturated with capillary water absorption, the water level in the water supply tank is almost constant, and the float valve is closed.

[0025] Figure 6 This is a schematic diagram of the dimensions of each section of wicking material when the photovoltaic panel provided by the present invention is installed at an angle.

[0026] Figure 7 This is a schematic diagram of the dimensions of each section of wicking material when the photovoltaic panel provided by the present invention is installed vertically.

[0027] Figure 8 This is a test chart of the center temperature of the back of the photovoltaic panel provided by the present invention with and without wicking material attached to the back.

[0028] Figure 9 This is a test chart of power generation when the back of the photovoltaic panel provided by the present invention is attached with wicking material (corduroy cloth) and when it is not attached with wicking material.

[0029] Description of the numbers in the figure:

[0030] 1-photovoltaic panel, 2-photovoltaic bracket, 3-wicking material, 4-water supply component, 41-water supply trough, 42-sinking rod, 43-float valve, 44-channel, 45-boss, 46-flip cover, 47-opening, 5-water pipe, 6-water storage tank, 7-adjustment and fixing component, 71-sticky hook, 72-chain, 8-support base, 9-base surface, 10-control valve. DETAILED DESCRIPTION

[0031] The present invention will be described in further detail below with reference to the accompanying drawings and examples. It is particularly noted that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Similarly, the following examples are only some embodiments of the present invention and are not intended to be exhaustive. All other embodiments obtained by those of ordinary skill in the art without creative effort are intended to fall within the scope of protection of the present invention.

[0032] See Figure 1 and Figure 2 The present invention discloses a passive cooling system for photovoltaic panels that automatically absorbs water and evaporates it for cooling, thereby improving the panel's power generation performance and service life. The system comprises: a photovoltaic panel 1, a photovoltaic support 2, a wicking material 3, a water supply assembly 4, a water pipe 5, a water storage tank 6, and an adjustment and fixing assembly 7.

[0033] The photovoltaic panel 1 is fixed and installed by the photovoltaic bracket 2, and the installation method is horizontal, inclined or vertical; the two ends of the water supply component 4 are arranged horizontally along the two side edges of the photovoltaic panel 1; wherein, the photovoltaic panel 1 is the main cooling structure, which is made of monocrystalline silicon or polycrystalline silicon, and its size can be customized according to demand. The photovoltaic panel 1 is fixed by the photovoltaic bracket 2, which can be connected with screws through triangular components. The photovoltaic bracket 2 is made of corrosion-resistant aluminum alloy or hot-dip galvanized steel. The installation angle is optimized and adjusted according to the latitude and light conditions of the installation site. Figure 1 As shown, when the photovoltaic panel 1 is installed at a certain angle to the horizontal plane or horizontally, the photovoltaic bracket 2 is fixed to the installation plane (such as a concrete roof or ground foundation) through stainless steel expansion bolts (such as M8×80mm). The connection points between the photovoltaic bracket 2 and the photovoltaic panel 1 are located at the four corners of the photovoltaic panel 1 to ensure that the back is unobstructed and provide a flat space for the attachment of the wicking material 3. Figure 2 As shown, when the photovoltaic panel 1 is installed vertically, photovoltaic brackets 2 are placed on both sides of the photovoltaic panel 1. The photovoltaic brackets 2 and the photovoltaic panel 1 are connected by welding and then fixed as a whole to the installation plane (such as a wall).

[0034] The wicking material 3 is attached to the back of the photovoltaic panel 1, with its lower end extending into the water supply assembly 4. This assembly is connected to a water tank 6 via a water pipe 5. An adjustment and fixing assembly 7 connects the water supply assembly 4 and the photovoltaic panel 1, respectively, to adjust the vertical position of the water supply assembly 4. The water supply assembly 4 supplies water to the wicking material 3, which automatically absorbs water from the bottom up due to capillary action. After absorbing water, the wicking material 3 absorbs heat from the photovoltaic panel 1, and the water evaporates, removing a large amount of heat. This evaporative cooling effect cools the photovoltaic panel 1, lowering its operating temperature. The water evaporated from the wicking material 3 is automatically replenished from the water supply assembly 4 due to capillary action, creating a continuous passive cooling mechanism.

[0035] The present invention requires no external energy source and achieves fully automatic water replenishment. During periods of high solar radiation and high temperatures, water evaporates more, resulting in a stronger cooling effect. However, during periods of low solar radiation and low temperatures, water evaporates less, resulting in a weaker cooling effect. This system achieves real-time climate control of the operating temperature of the photovoltaic panels 1. This system is particularly suitable for cooling photovoltaic panels 1 during power generation in dry, rainy, or ice-free regions, offering technical advantages such as high water conservation, low investment costs, easy operation and maintenance, and significant improvements in power generation efficiency.

[0036] In this embodiment, if Figure 3As shown, the wicking material 3 is a fabric with efficient capillary water absorption, such as quick-drying fabric, corduroy, or space cotton. It can be either an inorganic or organic hydrophilic material. The wicking material 3 has a vertical capillary water absorption height of no less than 150 mm, a thickness of 0.5 mm to 1 mm, a length greater than the length of the photovoltaic panel 1 (requires a certain length to extend into the water supply groove 41 for easy water absorption), and a width equal to the width of the photovoltaic panel 1. The wicking material 3 (Wicking Material) is a functional material with a unique microporous structure that automatically and directionally transports liquid from a low level to a high level through capillary action, without the need for external energy input. Its core characteristics are autonomous liquid absorption, uniform wetting, and efficient evaporation. The wicking material 3 has the following functional characteristics: (1) it can absorb water from bottom to top through capillary action, with a vertical capillary water absorption height of at least 150 mm, ensuring complete wetting of the back area of ​​the photovoltaic panel 1; (2) the material has good thermal conductivity, ensuring that heat is efficiently transferred from the back of the photovoltaic panel 1 to the water; (3) it has a long service life, is resistant to ultraviolet radiation, and has good anti-aging properties.

[0037] The wicking material 3 is attached to the back of the photovoltaic panel 1 through thermal grease. The thermal conductivity of the thermal grease is not less than 1W / (m·K) and the thickness is 0.5mm~1mm, which ensures that the heat generated on the back of the photovoltaic panel 1 can be efficiently transferred to the wicking material 3, thereby improving the cooling efficiency of the system. The wicking material 3 is tightly attached to the back of the photovoltaic panel 1 from top to bottom along the installation direction of the photovoltaic panel 1 through the thermal grease, and extends a certain length at the lower end of the wicking material 3. Before attachment, a thermal grease with a thickness of about 0.5mm is evenly applied to the back of the photovoltaic panel 1 to enhance the thermal contact between the wicking material 3 and the back of the photovoltaic panel 1. The lower end of the wicking material 3 extends beyond the edge to form a hanging part. The water absorption height of the wicking material 3 is determined by the principle of capillary action. According to the theory of capillary phenomenon, the rising height of the liquid in the capillary tube It can be expressed as:

[0038]

[0039] Where: is the rising height of the liquid ( ); is the surface tension coefficient of water ( ); is the contact angle of water and wicking material 3 ( ); is the density of water ( ); is the acceleration due to gravity ( ); is the equivalent capillary radius of the wicking material 3 ( ). In this system, the wicking material 3 is optimized by the equivalent capillary radius (typical range 0.1~0.5mm) and hydrophilic properties (contact angle 30°), to ensure the vertical capillary water absorption height 150mm, so as to wet the back of the photovoltaic panel 1 as much as possible. The formula shows that reducing the capillary radius or contact angle It can significantly improve water absorption capacity and provide a theoretical basis for system design.

[0040] In this embodiment, the water supply assembly 4 includes a water supply trough 41, a sinking rod 42 and a float valve 43. The water supply trough 41 is a rectangular parallelepiped structure and is made of corrosion-resistant PVC or aluminum alloy. The two ends of the water supply trough 41 are horizontally arranged along the two side edges of the photovoltaic panel 1, and the upper edge of the water supply trough 41 abuts against the side frame of the photovoltaic panel 1, forming a closed environment to reduce water evaporation, ensuring that the lower end of the wicking material 3 extends mostly immersed in water and is not exposed to the outside, thereby preventing water evaporation loss in non-functional areas;

[0041] The upper surface of the water supply trough 41 is provided with a long channel 44 in the horizontal direction and close to the photovoltaic panel 1, with a width of 1 to 2 cm, for accommodating the wicking material 3. The submerged rod 42 is installed in the water supply trough 41. The lower end of the wicking material 3 passes through the channel 44 and enters the water supply trough 41 and is fixed to the submerged rod 42. The end of the wicking material 3 is weighted or pulled by the submerged rod 42 to ensure that the lower part of the wicking material 3 is immersed in water. When the submerged rod 42 plays a weighting role, it can be made of a thin iron rod or iron wire with a length similar to that of the wicking material 3. The wicking material 3 has the same width and is attached to the end of the downwardly extending portion of the wicking material 3. Its density is greater than that of water and it is suspended in the water of the water supply tank 41. When the submerged rod 42 plays a pulling and reinforcing role, it can be made of a plastic rod or a PVC tube and attached to the inner wall of the water supply tank 41 to ensure that the wicking material 3 extends downward and is stably immersed in the water of the water supply tank 41. The water supply tank 41 is used to soak the lower end extension of the wicking material 3, replenishing the wicking material 3 with water through capillary absorption, thereby ensuring that the back of the photovoltaic panel 1 is moistened and cooled by evaporation.

[0042] The left end of the upper surface of the water supply tank 41 is connected to a boss 45. The top surface of the boss 45, which houses the float valve 43, is higher than the top surface of the water supply tank 41. A flap 46 is installed on the top of the boss 45. This flap 46 is openable and closable. An opening 47 is provided on the side of the boss 45 to accommodate the fixed end of the float valve 43. Once installed, the flap 46 closes the top surface to reduce water evaporation. The float valve 43 is mounted within the boss 45 and connected to the water storage tank 6 via a water pipe 5. This allows for automatic water replenishment and maintenance of a constant water level. After calibration, the water level fluctuation range is controlled to ≤2 mm, ensuring that the end of the wicking material 3 is always submerged. The water level in the water supply tank 41 is precisely controlled by the float valve 43 and automatically replenished by the water storage tank 6. The float valve 43 is installed on the side wall of the water supply tank 41 and is connected to the water storage tank 6 through the water pipe 5. It is used to accurately control the water level in the water supply tank 41 and control the liquid level in the water supply tank 41 to maintain a constant state (optimal infiltration conditions) to ensure that the extended part of the wicking material 3 is fully infiltrated; the float valve 43 is made of corrosion-resistant material and has high sensitivity. When the wicking material 3 continues to absorb water by capillary and causes the liquid level in the water supply tank 41 to drop, the float of the float valve 43 sinks, and the float valve 43 senses the water level change. The valve of the float valve 43 automatically opens, and water is introduced from the water storage tank 6 to replenish the water supply tank 41; when the liquid level in the water supply tank 41 returns to the set water level, the valve of the float valve 43 automatically closes, interrupting the water replenishment, forming an automatically balanced water level control system to maintain stable operation of the system.

[0043] In this embodiment, in actual application, the system design requires specific determination of the number and layout of water supply troughs 41 based on the installation inclination angle and dimensions of the photovoltaic panel 1. When the height H between the photovoltaic panel 1 and the horizontal plane (when the photovoltaic panel 1 is installed horizontally, H = 0; when the photovoltaic panel 1 is installed at an angle, H is related to the length L of the photovoltaic panel 1 and the inclination angle a between the photovoltaic panel 1 and the horizontal plane, i.e., H = Lsina; when the photovoltaic panel 1 is installed vertically, H = L) is no greater than the vertical capillary absorption height of the wicking material 3 (the maximum height to which water can rise from bottom to top), the capillary action of the wicking material 3 can overcome gravity and distance factors, effectively absorbing water from a single bottom water supply trough 41 upward to the entire back of the photovoltaic panel 1. In this case, a single water supply trough 41 can meet the water supply needs of the entire system. When the capillary absorption of a single piece of wicking material 3 can completely cover the back of the photovoltaic panel 1, a single water supply assembly 4 is used to achieve complete wetting and evaporation of the back of the photovoltaic panel 1.

[0044] When the height H formed between the photovoltaic panel 1 and the horizontal plane is greater than the vertical capillary water absorption height of the wicking material 3 (since H=0 when the photovoltaic panel 1 is installed horizontally, only the inclined and vertical installation situations need to be considered here), the capillary water supply range of a single water supply trough 41 is limited, and it is difficult to ensure that the area of ​​the wicking material 3 away from the water supply trough 41 is fully moistened. After the capillary water absorption of a single piece of wicking material 3 is soaked, it cannot completely cover the back of the photovoltaic panel 1. At this time, multiple water supply components 4 need to be distributed in a stepped manner along the installation direction of the photovoltaic panel 1. Each section of wicking material 3 corresponds to a water supply component 4, and each water supply trough 41 is responsible for moistening the wicking material 3 in its corresponding area, and together they ensure that the entire back of the photovoltaic panel 1 obtains complete and uniform moistening and evaporative cooling effects. The height formed between the effective length from the top of each section of wicking material 3 to the gas-liquid interface in the water supply trough 41 and the horizontal plane is less than or equal to the vertical capillary water absorption height of the wicking material 3:

[0045] ① When the photovoltaic panel 1 is installed at an angle, each section of the wicking material 3 can be divided into two parts. The first part is the inclined part of the wicking material 3 that is attached to the back of the photovoltaic panel 1 at an angle, and its effective length is l 1, the inclination angle is a, the length l The height h1 formed by 1 and the horizontal plane = l 1sina; The second is the lower end of the wicking material 3 extending into the vertical portion of the water supply tank 41, the effective length of the inclined portion and the vertical portion of the bend to the length corresponding to the gas-liquid interface in the water supply tank 41 l 2. The length l 2The height formed by the horizontal plane h2= l 2, i.e. the effective length from the upper end of the wicking material 3 to the gas-liquid interface in the water supply tank 41 ( l 1+ l 2) The height between the horizontal plane and the horizontal plane (h1+h2= l 1sina+ l 2) Since the vertical capillary water absorption height of the wicking material 3 is the maximum height to which the water in the water supply tank 41 can rise, it is necessary to ensure that each section of the wicking material 3 l 1sina+ l 2 is less than or equal to the vertical capillary water absorption height of the wicking material 3; Figure 6 As shown;

[0046] ② When the photovoltaic panel 1 is installed vertically, each section of the wicking material 3 can be divided into three parts. The first part is the vertical part of the wicking material 3 vertically attached to the back of the photovoltaic panel 1, and its effective length is l 3. The length l The height h3 formed by 3 and the horizontal plane = l 3; The second is an inclined portion formed from the vertical portion to the upper surface of the water supply trough 41 through the channel 44, the effective length of which isl 4. The inclination angle with the vertical direction is b, and the length l The height h4 formed by 4 and the horizontal plane = l 4sinb; The third is the vertical portion of the wicking material 3 extending from the upper surface of the water supply tank 41 into the water supply tank 41, and its effective length is the length corresponding to the bending point of the inclined portion and the vertical portion to the gas-liquid interface in the water supply tank 41 l 5. The length l The height h5 formed by 5 and the horizontal plane = l 5, i.e. the effective length from the upper end of the wicking material 3 to the gas-liquid interface in the water supply tank 41 ( l 3+ l 4+ l 5) The height between the horizontal plane (h3+h4+h5= l 3+ l 4sinb+ l 5) Since the vertical capillary water absorption height of the wicking material 3 is the maximum height to which the water in the water supply tank 41 can rise, it is necessary to ensure that each section of the wicking material 3 l 3+ l 4sinb+ l 5 is less than or equal to the vertical capillary water absorption height of the wicking material 3, such as Figure 7 As shown;

[0047] Each water supply assembly 4 is connected in series via a water pipe 5 and shares a common water storage tank 6. Each water supply tank 41 is connected to the water storage tank 6 via interconnected water pipes 5 and equipped with an independent float valve 43. This multi-supply tank 41 system operates in tandem and efficiently. Multiple water supply assemblies 4 and wicking material 3 ensure complete wetting and evaporation of the back of the photovoltaic panel 1.

[0048] In this embodiment, the adjustment and fixing assembly 7 includes two hooks 71 and two chains 72. The chains 72 can be iron chains. The two hooks 71 are respectively fixed to the two ends of the water supply trough 41 (the upper surface or front surface). One end of the chain 72 is fixed to the hook 71, and the other end is fixed to the edge of the photovoltaic panel 1. It is used to maintain the vertical state of the water supply trough 41, ensuring that the water supply trough 41 remains vertical when the photovoltaic panel 1 is installed at different inclination angles. By adjusting the length of the chain 72, the water supply trough 41 is always vertical when the photovoltaic panel 1 is installed at any inclination angle, preventing the wicking material 3 from escaping from the water surface.

[0049] In this embodiment, when the installation mode is horizontal, the photovoltaic panel 1 is parallel to the ground, and the four photovoltaic brackets 2 are respectively installed at the four corners of the photovoltaic panel 1;

[0050] When the installation mode is tilted, the photovoltaic panel 1 is tilted, and the range of the tilt angle a between the photovoltaic panel 1 and the ground is: 0°<a<90°, and the four photovoltaic brackets 2 are respectively installed at the four corners of the photovoltaic panel 1;

[0051] When the installation method is vertical, the photovoltaic panel 1 is perpendicular to the ground, and two photovoltaic brackets 2 are respectively installed on both sides of the photovoltaic panel 1.

[0052] This embodiment also includes a support base 8 and a base surface 9. The support base 8 and photovoltaic bracket 2 are mounted on the base surface 9. One end of the photovoltaic bracket 2 is fixed to the photovoltaic panel 1 to support and fix the photovoltaic panel 1, and the other end is fixed to the base surface 9. The base surface 9 can be flat, inclined, or vertical. The water tank 6 is mounted on the support base 8, which has an inverted U-shaped structure. The support base 8 is used to support the water tank 6 and is placed on the base surface 9. The material can be a steel frame or concrete structure to ensure stable support of the water tank 6 and the water therein.

[0053] In this embodiment, one side of the water tank 6 is connected to the water supply tank 41 via a water pipe 5, and the other side is connected to a water source via a water pipe 5. It also includes at least two control valves 10, which are installed on the water pipe 5 and close to the water tank 6. When water needs to be added, the control valve 10 can be opened; when the water volume does not need to be increased, the control valve 10 can be closed. The water tank 6 can be used to store tap water and recycled water, as well as to collect non-traditional water resources such as filtered rainwater and air conditioning condensate. The water tank 6 is a sealed container, and its volume is designed according to actual needs. The recommended volume is 50~100L. The material can be corrosion-resistant HDPE, fiberglass, or polyethylene, and has sun protection properties. Water tank 6 rests on support base 8 and is connected via two water pipes 5: an upper water pipe 5 (the inlet pipe) connects to a rainwater collection system or tap water connection, and a lower water pipe 5 (the outlet pipe) connects to a float valve 43, automatically replenishing water to water supply tank 41. A control valve 10 is installed on water pipe 5 for manually adjusting or shutting off the water flow.

[0054] like Figure 4 As shown, when the temperature of the photovoltaic panel 1 increases, causing the evaporation of water in the wicking material 3 to accelerate, the wicking material 3 continues to absorb water from the water supply tank 41, causing the water level in the water supply tank 41 to drop. At the same time, the float valve 43 automatically opens when it senses the water level change, and the water in the water storage tank 6 flows into the water supply tank 41 through the water pipe 5, replenishing the water lost by evaporation from the wicking material 3 in a timely manner. When the water level in the water supply tank 41 rises to a preset height, the float rises and the float valve 43 automatically closes, interrupting the water replenishment process ( Figure 5 ).

[0055] When the ambient temperature is high and solar radiation is strong, the evaporation rate of the wicking material 3 accelerates, the float valve 43 opens more frequently to replenish water, and the system's cooling effect is enhanced. When the ambient temperature is low and solar radiation is weak, the evaporation rate decreases, the float valve 43 opens less frequently to replenish water, and the cooling effect is appropriately weakened, thereby achieving real-time climate control of the operating temperature of the photovoltaic panel 1. This automatic dynamic adjustment of water absorption and replenishment enables the system to adjust the cooling intensity according to actual environmental conditions, avoiding unnecessary water consumption.

[0056] Through the above implementation, the system can achieve efficient passive cooling of the photovoltaic panel 1, significantly improve power generation efficiency and extend component life, while having the advantages of low maintenance cost, high adaptability and environmental friendliness.

[0057] To verify the actual cooling and power-increasing effects of the present invention, the center temperature and power generation of a photovoltaic panel (1) with and without wicking material attached to the backsheet were measured on the roof of a building. The selected photovoltaic panel (1) had a rated power generation of 30W and a width of 430mm. It was tilted 18° toward due south and placed in an unobstructed area of ​​the roof, with a tilt length of 460mm. The vertical water absorption height of the selected wicking material, 3-cord velvet, was 221mm, resulting in a tilted water absorption length of 715.17mm for the photovoltaic panel (1). A single water supply trough (41) was sufficient to meet the cooling requirements of the photovoltaic panel (1). The center temperature and power generation of the backsheet were measured using a thermocouple and a multimeter, respectively. The test period was sunny in summer, with the temperature test period from 6:00 AM to 6:00 PM and the power generation test period from 9:00 AM to 4:00 PM. The ambient temperature was between 28°C and 35°C, the relative humidity was between 60% and 75%, and the irradiance on the tilted surface was a maximum of 1050 W / m².

[0058] from Figure 8 It can be seen that the cooling system provided by the invention can significantly reduce the temperature of the back panel of the photovoltaic panel 1. The center temperature of the photovoltaic panel 1 with corduroy cloth attached can be reduced by up to 18°C ​​compared to the unattached material. The cooling effect is good and better than the cooling effect of most current cooling methods. During the noon period, the power generation of the photovoltaic panel 1 cooled by the system is significantly higher than that of the uncooled photovoltaic panel 1, with a maximum power increase of 2.6W, an increase of about 10%, and a significant power increase effect ( Figure 9 ).

[0059] The above description is merely an example of a preferred embodiment of the present invention and does not limit the scope of the present invention. In other words, equivalent changes and modifications made within the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

[0060] The above descriptions are only some embodiments of the present invention and do not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling, characterized in that: include: Photovoltaic panels, photovoltaic brackets, wicking material, water supply components, water pipes, water storage tanks, and adjustment and fixing components; the photovoltaic panels are fixedly mounted via the photovoltaic brackets, and the mounting method can be horizontal, inclined, or vertical; the two ends of the water supply components are arranged horizontally along the two side edges of the photovoltaic panels; the wicking material is attached to the back of the photovoltaic panels, and its lower end extends into the water supply components; the water supply components are connected to the water storage tank via the water pipes; the adjustment and fixing components are respectively connected to the water supply components and the photovoltaic panels, and are used to adjust the vertical state of the water supply components; The water supply assembly includes a water supply trough, a sinking rod and a float valve. The water supply trough is a rectangular structure. The two ends of the water supply trough are horizontally arranged along the two side edges of the photovoltaic panel, and the upper edge of the water supply trough is in contact with the side frame of the photovoltaic panel; the upper surface of the water supply trough is provided with a long strip channel in the horizontal direction and close to the photovoltaic panel for accommodating wicking material, the sinking rod is installed in the water supply trough, and the lower end of the wicking material passes through the channel into the water supply trough and is fixed to the sinking rod; the left end of the upper surface of the water supply trough is connected to a boss, and the top surface of the boss is provided with a flip cover. The float valve is installed in the boss and is connected to the water tank through a water pipe, which is used to automatically replenish water and maintain a constant water level; when the height formed between the photovoltaic panel and the horizontal plane is greater than the vertical capillary water absorption height of the wicking material, multiple water supply components are distributed in a stepped manner along the installation direction of the photovoltaic panel, each section of wicking material corresponds to a water supply component, and the height formed between the effective length from the upper end to the gas-liquid interface in the water supply tank in each section of wicking material and the horizontal plane is less than or equal to the vertical capillary water absorption height of the wicking material, and the water supply components are connected in series through the water pipe and share the same water tank.

2. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: The wicking material is quick-drying cloth, corduroy cloth or space cotton, and the vertical capillary water absorption height of the wicking material is not less than 150 mm.

3. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: The wicking material is attached to the back of the photovoltaic panel through thermal conductive silicone grease, and the thermal conductivity of the thermal conductive silicone grease is not less than 1W / (m·K).

4. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: The adjustment and fixing assembly includes two adhesive hooks and two chains. The two adhesive hooks are respectively fixed to the two ends of the water supply trough. One end of the chain is fixed to the adhesive hook, and the other end is fixed to the edge of the photovoltaic panel to maintain the vertical state of the water supply trough.

5. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: When the installation method is horizontal, the photovoltaic panel is parallel to the ground, and four photovoltaic brackets are installed at the four corners of the photovoltaic panel respectively; When the installation mode is tilted, the photovoltaic panel is tilted, and the range of the tilt angle a between the photovoltaic panel and the ground is: 0°<a<90°, and four photovoltaic brackets are respectively installed at the four corners of the photovoltaic panel; When the installation method is vertical, the photovoltaic panel is perpendicular to the ground, and two photovoltaic brackets are respectively installed on both sides of the photovoltaic panel.

6. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: One side of the water storage tank is connected to the water supply tank through a water pipe, and the other side is connected to the water source through a water pipe.

7. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 6, characterized in that: The device also includes at least two control valves, which are installed on the water pipe and close to the water tank.

8. The photovoltaic panel passive cooling system based on capillary action for automatic water absorption and evaporation cooling as claimed in claim 1, characterized in that: It also includes a support base and a base surface, the support base and the photovoltaic bracket are installed on the base surface, and the water tank is installed on the support base; the support base is an inverted U-shaped structure.

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