A new energy photovoltaic box-type transformer cooling device

Abstract

The application discloses a new energy photovoltaic box-type transformer cooling device, and belongs to the technical field of transformer cooling. The opening layer is provided with a slit-shaped notch, and sound-induced flow is generated under the high-frequency driving of a piezoelectric transducer, so that the air boundary layer on the surface of the heat sink is broken; the stack layer can adsorb the condensed water transported by the capillary and evaporate quickly under the action of sound waves, so that the cooling effect of the combination of acoustic disturbance and liquid evaporation is realized. The micro-spine structure is used for collecting and guiding the condensed water to the stack layer, the underground condensation plate forms a closed-loop water circulation for water supply in the daytime and backflow at night. The cavity layer is designed as a turn-back channel and is matched with the driving frequency to form a quarter wavelength, the back plate is provided with a secondary back cavity and adopts a micro-perforated impedance plate, so that the differential cooling of the hot spot area, the enhancement of acoustic standing wave and the optimization of impedance are realized. The application fully utilizes the residual electricity on the direct current side of the photovoltaic system for driving, does not need additional energy consumption, can significantly reduce the operating temperature rise of the box-type transformer, and improves the safety and stability of the equipment.

Description

Technical Field

[0001] This invention relates to the field of transformer cooling technology, specifically a cooling device for a new energy photovoltaic box-type transformer. Background Technology

[0002] The rapid development of new energy photovoltaic power plants has led to the widespread application of box-type transformers in photovoltaic power generation systems. As a core piece of equipment in photovoltaic power plants, box-type transformers operate outdoors for extended periods, undertaking the critical tasks of energy conversion and grid connection. During actual operation, the windings and core of the box-type transformer generate a significant amount of heat. Insufficient heat dissipation will cause the transformer enclosure temperature to rise excessively, not only reducing operating efficiency but also potentially causing insulation aging or even equipment failure, seriously threatening the safety and stability of the power system.

[0003] In existing technologies, heat dissipation of box-type transformers mainly relies on two methods: natural air cooling and forced air cooling. Natural air cooling mainly relies on the natural convection between the outer casing and heat sink and the air. Although it has a simple structure and low energy consumption, its heat dissipation effect is limited under high temperature or full load operating conditions. Forced air cooling usually improves heat dissipation capacity by installing fans to force airflow, but this method has problems such as high energy consumption, high noise, high maintenance costs, and insufficient reliability in harsh outdoor environments.

[0004] Some improved technologies attempt to add fin structures to the surface of the heat sink or use liquid-cooled pipes for heat transfer. While these technologies can improve heat exchange efficiency to some extent, they generally have the following shortcomings: First, the structure relies on mechanical components, which are prone to dust accumulation, blockage, or failure during long-term operation; second, the liquid cooling system requires additional pump circulation and cooling medium replenishment, increasing energy consumption and maintenance costs; third, the above methods are mostly enhancements of a single physical mechanism and fail to fully utilize the acoustic energy, ambient humidity, and photovoltaic surplus electricity available in the operating environment of the box-type transformer, so the overall heat dissipation efficiency remains limited.

[0005] Therefore, existing technologies achieve cooling of box-type transformers through natural air cooling, forced air cooling, or liquid cooling, but they still have certain limitations, such as insufficient heat dissipation efficiency, high energy consumption, poor reliability, and difficulty in adapting to the day-night operating characteristics of photovoltaic power plants.

[0006] Therefore, there is an urgent need for a new type of box-type transformer cooling device that is compact, energy-efficient, and highly adaptable. This device can enhance convection by utilizing acoustic disturbances, combined with the latent heat of condensate evaporation and photovoltaic DC surplus power drive, to achieve low energy consumption, high efficiency, and long-term stable cooling effect, thereby solving the problems of insufficient heat dissipation efficiency and excessive energy consumption in existing technologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and propose a cooling device for a new energy photovoltaic box-type transformer to solve the above-mentioned problems.

[0008] The objective of this invention is achieved through the following technical solution: a cooling device for a new energy photovoltaic box-type transformer, comprising:

[0009] The outer casing of the enclosure has multiple heat sinks fixed to its outer side;

[0010] The resonant panel is fixed to the outer surface of the heat sink. The resonant panel is arranged in the same direction as the fins of the heat sink and is tightly attached by a thermally conductive interface material. It is used to acoustically disturb the air boundary layer corresponding to the heat generated by the winding and iron core inside the housing.

[0011] The resonant panel includes:

[0012] An open layer with slit-like slots evenly distributed on it, the width of which is less than 2 mm and the length is more than 5 times the width, is used to form an acoustic jet nozzle.

[0013] A cavity layer, located between the opening layer and the back plate, with a cavity depth of 2–6 mm, is used to form an acoustic standing wave field;

[0014] A stacked layer, located within the cavity layer, is a hydrophilic porous material with a pore size ranging from 20 to 100 micrometers. It is used to achieve the separation of hot and cold air molecules and adsorb condensate under the action of sound waves.

[0015] The backplate is a thin metal plate, and a piezoelectric transducer is attached to the outside of the backplate. The piezoelectric transducer is a ceramic piezoelectric sheet or a thin film piezoelectric unit, which is used to drive the cavity layer to generate high-frequency sound waves of 20–40 kHz.

[0016] The underground condensing plate is located in the soil constant temperature zone below the outer shell of the box. The underground condensing plate is a metal plate with a hydrophilic porous layer on the surface, which is used to collect condensation formed by air moisture under low temperature conditions at night.

[0017] The capillary tube, with a hydrophilic capillary core structure on the inner wall, connects the underground condenser plate to the stacked layer of the resonant panel, and is used to transport condensate to the stacked layer.

[0018] In this process, the condensate adsorbed by the stack layer evaporates rapidly under the action of high-frequency sound waves generated by the piezoelectric transducer, thereby achieving heat exchange that couples acoustic disturbance with liquid evaporation in the local heat sink area of ​​the outer shell.

[0019] The outer side of the slot of the opening layer is integrally formed with a micro-spiky structure. The micro-spiky structure is a conical protrusion with a height of less than 3 mm and a spacing of less than 10 mm. It is used to collect condensate in the air around the box and guide it to the stack layer along the guide groove. A hydrophobic isolation strip is set between the slot and the micro-spiky structure.

[0020] The stacked layers are sintered metal foam sheets or ceramic sintered sheets with a thickness of 0.5–2 mm, used to maintain the liquid film and accelerate liquid evaporation when the housing is under heavy load.

[0021] The capillary tube is equipped with a one-way flow guide valve, which is used to guide the condensate generated by the underground condenser plate to the stack layer when the outer shell of the box is under high load during the day, and to allow the water condensed in the stack layer to flow back to the underground condenser plate when the load is low at night.

[0022] The opening layer and the slot are integrally pressed and formed. The chamfer radius of the two ends of the slot is less than 0.5 mm, which is used to enhance acoustic flow and improve the disturbance effect of the air boundary layer on the surface of the heat sink.

[0023] The piezoelectric transducers are arranged in an array with a unit size of less than 30 mm, enabling zoned drive to perform acoustically enhanced heat transfer on the heat sink area corresponding to the hot spots generated by the windings or iron core inside the housing.

[0024] The surface of the underground condenser plate is coated with an aluminum oxide or silica-based superhydrophilic coating with a thickness of less than 100 micrometers to enhance the condensation efficiency of air moisture in the nighttime operation environment of the enclosure.

[0025] The cavity layer of the resonant panel is a folded-back channel structure. The equivalent channel length of the folded-back channel is related to the driving frequency of the piezoelectric transducer by a quarter wavelength. This structure is used to improve the acoustic standing wave intensity and adapt to the surface heat exchange requirements of the heat sink.

[0026] A secondary back cavity is provided between the back plate and the back of the cavity layer. The back plate is a micro-perforated impedance plate. The secondary back cavity is not connected to the outside world and is used to improve acoustic impedance matching and steam discharge during the evaporative cooling process of the enclosure shell.

[0027] The piezoelectric transducer is powered by the surplus DC power from the photovoltaic power generation system to which the housing is located, thus achieving acoustic drive of the resonant panel without increasing additional energy consumption.

[0028] The beneficial effects of this invention are:

[0029] This invention uses a resonant panel that is tightly attached to the outer surface of the heat sink of the housing shell, so that the acoustic disturbances can directly act on the heat dissipation path of the transformer. This ensures that the sound wave energy can play a role at the position corresponding to the air boundary layer of the heat sink, and the heat dissipation efficiency is significantly improved compared with independent heat dissipation units.

[0030] The resonant panel consists of an opening layer, a cavity layer, a stacked layer, and a backplate. Narrow slots are evenly arranged on the opening layer. The slots are integrally pressed and formed with small-radius chamfers at both ends. This design can form a stable acoustic flow under the action of high-frequency sound waves, reduce flow separation, break the air boundary layer attached to the surface of the heat sink, and thus greatly improve the convective heat transfer capacity.

[0031] The stack layer is made of a hydrophilic porous material, which achieves a thermal separation effect of air molecules under the action of sound waves. At the same time, it can adsorb liquid through capillary action and form a uniform liquid film. When condensate is introduced into the stack layer, the sound waves accelerate the evaporation of water, and the consumption of latent heat of vaporization further removes heat, achieving a coupling effect of acoustic cooling and evaporative cooling, making the cooling capacity significantly better than either method.

[0032] A micro-spiky structure is integrally formed on the outside of the slot in the opening layer. This structure promotes the condensation of moisture in the airflow field and collects it into small droplets. The condensate is then guided into the stack layer through the guide groove. At the same time, a hydrophobic isolation zone is set between the slot and the micro-spiky structure to effectively prevent condensate from crossing the slot and causing blockage, thus ensuring the stability of the resonant panel under high-frequency operation.

[0033] The underground condenser plate is located in the constant-temperature zone of the soil and its surface is coated with a hydrophilic coating. This significantly improves the condensation efficiency of air moisture under low-temperature conditions at night, continuously providing a water source for the system. Condensate is introduced into the stack layer through capillary tubes equipped with one-way flow-directing valves. This allows condensate to be drawn to the stack layer for evaporative cooling during high-load daytime operation, while at night, under low-load conditions, the condensate in the stack layer flows back to the underground condenser plate, achieving a closed-loop water circulation. This biomimetic collection and capillary supply method ensures a stable liquid supply during the cooling process, further enhancing long-term operational reliability.

[0034] To meet the heat dissipation requirements of different parts during the operation of box-type transformers, this invention designs the piezoelectric transducers as an array with partitioned arrangement. The unit size is small, and it can independently drive the hot spots formed by the windings or iron core to form differentiated enhanced cooling, avoid energy waste, and effectively control the risk of local overheating.

[0035] The cavity layer adopts a folded-back channel design, and its equivalent acoustic channel length maintains a quarter-wavelength matching relationship with the driving frequency of the piezoelectric transducer. This enhances the acoustic standing wave intensity within a limited space, ensures the formation of a high-velocity gradient acoustic flow at the slot opening, and further improves the heat exchange effect.

[0036] The back panel adopts a micro-perforated impedance plate structure, with a secondary back cavity behind it. This secondary back cavity is not connected to the outside world, enabling impedance matching of sound waves and creating a more stable acoustic field distribution inside the resonant panel, thus reducing sound energy loss. Simultaneously, the secondary back cavity also provides a buffer space for water vapor generated during evaporation, allowing for smoother steam discharge through the slot and preventing steam stagnation from affecting acoustic performance and heat exchange capacity.

[0037] In addition, the piezoelectric transducer is driven by surplus DC power from the photovoltaic power generation system, which can achieve high-frequency acoustic drive without increasing additional energy consumption, fully demonstrating the energy-saving and green operation advantages in new energy scenarios.

[0038] In summary, this invention achieves a multi-physics coupled overall cooling system through a combination of technical features, including acoustic disturbance of the resonant panel, liquid evaporation of the stacked layer, biomimetic collection of the opening layer, water circulation supply from the underground condenser plate, zoned drive of the piezoelectric transducer, acoustic folding back of the cavity layer, and impedance optimization of the backplate. This system can fully adapt to the operating conditions of the box-type transformer, maintaining stable and efficient cooling capacity under both heavy daytime loads and light nighttime loads, effectively reducing operating temperature rise, improving equipment safety and reliability, and possessing significant practical value and promising prospects for widespread application. Attached Figure Description

[0039] Figure 1 This is an overall structural diagram of the present invention;

[0040] Figure 2 This is a partial structure of the present invention. Figure 1 ;

[0041] Figure 3 For the present invention Figure 2 Sectional view of AA;

[0042] Figure 4 For the present invention Figure 2 BB section view;

[0043] Figure 5 The local explosion of the present invention Figure 1 ;

[0044] Figure 6 The local explosion of the present invention Figure 2 ;

[0045] Figure 7 This is an exploded view of the entire invention;

[0046] Figure 8 This is a partial structure of the present invention. Figure 2 .

[0047] Explanation of the labels in the diagram

[0048] 1. Enclosure; 2. Heat sink; 3. Resonant panel; 31. Opening layer; 311. Groove; 312. Micro-spiky structure; 32. Cavity layer; 33. Backplate; 34. Stack layer; 35. Piezoelectric transducer; 4. Underground condenser plate; 5. Capillary tube. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that the directional concepts of "left", "right", "up", "down", "front", "back", "inner", and "outer" in the following scheme are all relative directions, and will not be listed one by one here.

[0051] Example 1:

[0052] like Figures 1 to 8 As shown in Embodiment 1, a cooling device for a new energy photovoltaic box-type transformer is disclosed. This device is specifically adapted to the heat dissipation requirements of the box shell 1. It utilizes the acoustic disturbance of the resonant panel 3 combined with the liquid evaporation effect to form an overall cooling system, which can effectively solve the problems of low heat dissipation efficiency and excessive temperature rise of the box-type transformer in the prior art.

[0053] The outer casing 1 is a conventional rectangular metal shell with multiple heat sinks 2 evenly arranged on its outer side. The heat sinks 2 are arranged vertically, and their main function is to dissipate the heat generated by the windings and iron core inside the outer casing 1 during operation through natural convection. However, the heat transfer capacity of the heat sinks 2 alone is limited, especially in the high temperatures of summer and when the photovoltaic power station is operating at full load, the outer casing 1 is prone to excessive temperature rise. Therefore, a resonant panel 3 is attached to the outer surface of the heat sinks 2 to further enhance the convective heat transfer and evaporative cooling capacity.

[0054] The resonant panel 3 is installed by tightly adhering its back surface to the outer surface of the heat sink 2 via a thermally conductive interface material. This ensures that the heat from the heat sink 2 can be directly conducted to the resonant panel 3, avoiding excessive thermal resistance caused by an air layer in between. The resonant panel 3 is arranged in the same direction as the fins of the heat sink 2, so that the acoustic disturbance it generates matches the heat exchange airflow direction of the heat sink 2, thereby maximizing the disturbance effect at the air boundary layer outside the heat sink 2.

[0055] The resonant panel 3 comprises four parts: an opening layer 31, a cavity layer 32, a stacked layer 34, and a backplate 33. The opening layer 31 faces the air and has uniformly arranged slit-like slots 311. Each slot 311 has a width less than 2 mm and a length more than five times its width, thus creating a strong jet effect under the influence of sound waves. The slots 311 are integrally formed onto the opening layer 31 by stamping, and the edges at both ends of the slots are chamfered with a small radius of less than 0.5 mm. This design reduces airflow separation at the slots, lowering acoustic energy loss, and enhances the intensity of the acoustic flow formed by the slots 311, making it easier for disturbances to break through the boundary layer on the surface of the heat sink 2.

[0056] The cavity layer 32 is located between the opening layer 31 and the back plate 33. Its depth is designed to be in the range of 2–6 mm, so that the cavity layer 32 can form a standing wave resonance with the high frequency sound wave of 20–40 kHz under the excitation of the piezoelectric transducer 35. The standing wave establishes a sound pressure gradient and velocity gradient in the cavity layer 32, providing conditions for the heat exchange function of the stack layer 34.

[0057] The stacked layer 34 is arranged inside the cavity layer 32 and is made of a hydrophilic porous material with a pore size between 20 and 100 micrometers. This pore size range ensures that air molecules undergo a thermal separation effect under acoustic vibration, while also allowing liquid to be adsorbed through capillary action. Driven by acoustic waves, the gas molecules inside the stacked layer 34 undergo rapid alternating compression and expansion, forming a thermal separation zone. When condensate is adsorbed on its surface, the acoustic waves accelerate the evaporation of the water film. The evaporation process consumes latent heat, thereby further removing heat from the heat sink 2.

[0058] The backplate 33 is made of a thin metal sheet and is used to seal the cavity layer 32. A piezoelectric transducer 35 is adhered to its outer surface. The piezoelectric transducer 35 is a ceramic piezoelectric sheet or a thin-film piezoelectric unit, which can operate stably in the frequency range of 20–40 kHz. In this embodiment, the power supply of the piezoelectric transducer 35 comes from the surplus DC power of the photovoltaic power generation system, ensuring that the resonant panel 3 does not increase additional energy consumption during operation, thereby achieving green operation. The top of the opening layer 31 has a through hole corresponding to the stacked layer 34, which communicates with the outside. The top of the backplate 33 extends towards the opening layer 31 to block the through hole at the top of the opening layer 31 to prevent rainwater from entering and to allow water vapor to evaporate.

[0059] To provide the moisture required for evaporative cooling, an underground condenser plate 4 is buried in the constant-temperature soil zone beneath the outer shell 1. The underground condenser plate 4 is a metal plate with a hydrophilic porous layer on its surface, which promotes the condensation of water vapor in the air into water droplets and their storage under low-temperature conditions at night. The underground condenser plate 4 is connected to the stacked layer 34 of the resonant panel 3 via capillary tubes 5. The capillary tubes 5 have a hydrophilic capillary core structure on the inner wall, which can transport the condensate collected by the underground condenser plate 4 to the stacked layer 34 through capillary action, keeping the stacked layer 34 moist during the day, thereby achieving efficient evaporative cooling under the acoustic wave action of the piezoelectric transducer 35.

[0060] The working process of this embodiment is as follows: When the transformer is operating normally, the windings and core inside the housing 1 generate heat, which is conducted to the outer surface through the heat sink 2. At this time, the piezoelectric transducer 35 operates under the drive of the residual electricity on the DC side of the photovoltaic power generation system, exciting the air in the cavity layer 32 to form a high-frequency standing wave. Under the action of the standing wave, the gas molecules in the stack layer 34 undergo a thermal separation effect, and at the same time, the acoustic flow formed at the slot 311 continuously disturbs the air boundary layer, breaking the air film originally attached to the surface of the heat sink 2, thus enhancing the air convection heat transfer capacity. Meanwhile, the capillary tube 5 introduces the condensate collected by the underground condenser plate 4 into the stack layer 34. The water evaporates rapidly under the drive of the acoustic waves, and the latent heat of evaporation further removes the heat from the heat sink 2. Finally, the acoustic disturbance and evaporative cooling work together to significantly improve the heat transfer coefficient of the heat sink 2 and significantly reduce the surface temperature rise of the housing 1.

[0061] By directly attaching the resonant panel 3 to the heat sink 2, the acoustic disturbance can be directed towards the heat exchange path of the transformer, maximizing the utilization rate of acoustic energy. The slot 311 is integrally formed and has a small radius chamfer at the end, which reduces airflow loss and increases the intensity of acoustic flow. Under the action of acoustic waves from the cavity layer 32, the stacked layer 34 can achieve both hot and cold separation of air molecules and water absorption and evaporation, combining acoustic cooling and evaporative cooling, significantly improving cooling efficiency. The piezoelectric transducer 35 is powered by the surplus DC power from the photovoltaic power generation system, ensuring that no external power supply is needed for the entire cooling process, meeting the green energy-saving requirements of new energy photovoltaic power plants. Overall, this embodiment can effectively reduce the temperature rise of the box-type transformer during operation, improve the safety and stability of equipment operation, and has significant practical value.

[0062] Example 2:

[0063] like Figures 1 to 8As shown, Embodiment 2 further optimizes the acquisition and utilization of condensate based on Embodiment 1. By setting micro-spiky structures 312 in the opening layer 31, improving the material and thickness of the stack layer 34, adding a one-way flow guide valve in the capillary tube 5, and applying a hydrophilic coating to the surface of the underground condenser plate 4, the resonant panel 3 can combine with the ambient condensate for enhanced evaporation, achieving day and night cycle utilization, thereby obtaining a more stable and efficient cooling effect in actual operation.

[0064] In this embodiment, multiple micro-spiky structures 312 are integrally formed on the outer side of the slot 311 of the opening layer 31. The micro-spiky structures 312 are conical protrusions with a single height of less than 3 mm and a spacing of less than 10 mm. These micro-spiky structures 312 can induce changes in the airflow field during the operation of the outer shell 1 and promote the condensation of water vapor in the air into small droplets on their surface. Guided by the micro-spiky structures 312, the droplets flow along the grooves and gradually collect, then are transferred to the stack layer 34 through capillary action. To prevent condensate droplets from crossing the slot 311 and directly entering the cavity layer 32, which would lead to a decrease in cavity performance, a hydrophobic isolation zone is specially designed between the slot 311 and the micro-spiky structures 312 to ensure that the slot 311 remains unobstructed under any circumstances, thereby maintaining a stable acoustic flow effect.

[0065] In this embodiment, the stack layer 34 is made of sintered metal foam sheets or ceramic sintered sheets, with a thickness controlled within the range of 0.5–2 mm. Compared with the broader porous materials in Embodiment 1, this stack layer 34 has higher structural strength and stability, and can maintain a uniform pore distribution under the action of high-frequency sound waves. This facilitates the generation of the cold and hot separation effect of air molecules and can form a uniform liquid film when adsorbing liquid, thereby significantly accelerating the liquid evaporation rate during the high-load operation of the outer shell 1.

[0066] In this embodiment, the capillary tube 5 is equipped with a one-way flow guide valve. This valve automatically adjusts the flow direction of condensate based on the differences in day and night operating environments. During the day, when the outer casing 1 is under high load, the one-way flow guide valve remains open, and the condensate collected on the underground condensing plate 4 is guided through the capillary tube 5 to the stack layer 34, where it evaporates rapidly under the influence of sound waves, creating a significant evaporative cooling effect. At night, when the ambient temperature decreases and the load on the outer casing 1 drops, moisture easily re-condenses on the surface of the stack layer 34. At this time, the one-way flow guide valve allows the condensate to flow back to the underground condensing plate 4, achieving condensate recovery and reuse, and ensuring a closed-loop water resource circulation system.

[0067] In this embodiment, the underground condenser plate 4 is further improved by coating its surface with a hydrophilic coating less than 100 micrometers thick. The coating can be made of alumina or silica. This hydrophilic coating can significantly reduce the contact angle of the condenser plate 4 surface, thereby enhancing the condensation efficiency of air moisture in low-temperature environments at night, allowing more moisture to be collected and stored, and ensuring the stability of the water supply for evaporative cooling during the day.

[0068] During operation, when the photovoltaic power station generates electricity under high load during the day and the internal windings and core of the casing 1 generate more heat, the heat sink 2 conducts heat to the outer surface. The piezoelectric transducer 35 in the resonant panel 3 is powered by the surplus DC power from the photovoltaic power generation system, and under high-frequency drive of 20–40 kHz, it generates a standing wave field in the cavity layer 32. The slot 311 forms an acoustic flow under the drive of acoustic waves, breaking the boundary layer on the surface of the heat sink 2 and significantly improving the air convection heat transfer efficiency. At the same time, the capillary tube 5 introduces the condensate collected by the underground condenser plate 4 into the stack layer 34 through a one-way flow guide valve. The stack layer 34 uniformly absorbs this condensate and evaporates it rapidly under the drive of acoustic waves. The consumption of the latent heat of vaporization further removes the heat from the surface of the heat sink 2, thus achieving the dual effects of acoustic cooling and evaporative cooling. At night, when the ambient temperature drops and the load on the outer shell 1 of the enclosure is reduced, air moisture will re-condense on the surface of the stack layer 34 and the micro-spiky structure 312 of the opening layer 31. The condensate will flow back to the underground condenser plate 4 through the one-way flow guide valve under the action of gravity and capillary action, so as to realize the recovery and storage of water and ensure the closed-loop operation of water circulation.

[0069] In this embodiment, the micro-spiky structure 312 is used not only for collecting and guiding condensate during normal operation, but also works in conjunction with the opening layer 31 when the transformer requires rapid cooling. Specifically, when the temperature of the outer casing 1 rises rapidly and conventional evaporative cooling is insufficient to meet the cooling requirements, the surface of the micro-spiky structure 312 can form a micro-siphon under capillary action, directly introducing condensate into the surface of the micro-spiky structure 312. Driven by the piezoelectric transducer 35, the opening layer 31 generates high-frequency vibration, forming a strong acoustic flow and a local low-pressure zone on the surface of the micro-spiky structure 312, causing droplets to break up and evaporate rapidly on the surface of the micro-spiky structure 312. The latent heat of vaporization instantly carries away a large amount of heat, thereby achieving enhanced heat dissipation in a short time. Thus, the opening layer 31 not only serves as an acoustic disturbance interface, but also functions as a droplet collection and evaporation point. The micro-spiky structure 312 and the opening layer 31 are tightly coupled, enabling the system to flexibly switch between conventional steady-state cooling and rapid response to high-temperature conditions, further improving the environmental adaptability and safety of the device.

[0070] By setting micro-spiky structures 312 on the outside of the slots 311 of the opening layer 31 and combining them with a hydrophobic isolation strip, not only can condensate be collected and guided, but the unobstructed flow and stability of the slots 311 under high-frequency acoustic excitation are also ensured. The stack layer 34 uses sintered metal foam sheets or ceramic sintered sheets, which have suitable thickness and porosity characteristics, enabling stable and efficient evaporative cooling under the action of sound waves and liquid. The capillary tube 5, combined with a one-way flow guide valve, enables the system to have a "daytime water supply, nighttime return" circulation logic, effectively avoiding water waste. The surface of the underground condenser plate 4 is coated with a hydrophilic coating, which improves the condensation efficiency in the low-temperature environment at night and ensures sufficient condensate supply. Overall, this embodiment, through the combination of a biomimetic collection structure and a water circulation system, significantly improves the environmental adaptability and long-term operational stability of the resonant panel 3, making the cooling effect more durable and reliable, and further enhancing the safety and operating efficiency of the new energy photovoltaic box transformer.

[0071] Example 3:

[0072] like Figures 1 to 8 As shown, in Embodiment 3, the acoustic structure of the resonant panel 3 is further optimized based on Embodiments 1 and 2, and partitioned driving and impedance control are introduced to better adapt to the heat dissipation requirements of the housing 1 under different load conditions, and to achieve differentiated enhanced cooling for local hot spots in the winding and iron core.

[0073] In this embodiment, the piezoelectric transducer 35 is no longer arranged as a single integral unit, but is divided into multiple independent units, which are attached to the outer surface of the backplate 33 in an array. The size of each unit is less than 30 mm. This array arrangement enables the resonant panel 3 to achieve independent zone driving. That is, according to the hot spot location detected by the temperature sensor inside the housing 1, the piezoelectric transducer 35 unit corresponding to the hot spot area can be selectively excited, thereby forming an acoustic disturbance and liquid evaporation coupling effect in the corresponding heat sink 2 area. Through this zone driving method, the resonant panel 3 can avoid excessive disturbance to areas that do not need cooling, improve energy utilization, and at the same time form enhanced heat transfer in the hot spot area, ensuring the safe operation of the housing 1 under high load conditions.

[0074] To enhance the stability and intensity of the acoustic standing waves, this embodiment designs the cavity layer 32 as a folded-back channel structure. The folded-back channel extends the propagation path of the sound waves within the cavity layer 32, and its equivalent channel length is designed to maintain a quarter-wavelength matching relationship with the driving frequency of the piezoelectric transducer 35. Through this acoustic structural optimization, the cavity layer 32 can achieve stronger acoustic standing waves within a smaller volume, thereby generating a higher velocity gradient acoustic flow at the slot 311, significantly enhancing the disturbance effect on the air boundary layer of the heat sink 2 surface. This design is particularly suitable for the high heat dissipation requirements of the enclosure 1 during full-load operation in summer.

[0075] Furthermore, in this embodiment, a secondary back cavity is provided between the back plate 33 and the back of the cavity layer 32. The back plate 33 adopts a micro-perforated impedance plate structure. The diameter of the micro-perforations on the back plate 33 is between 0.1 and 0.5 mm, and the opening ratio is controlled between 3 and 10%. The secondary back cavity is not connected to the outside world. Its main function is to perform impedance matching for sound waves, so that a more stable acoustic energy distribution is formed inside the resonant panel 3, while avoiding the reduction in efficiency caused by acoustic energy leakage. More importantly, the secondary back cavity can provide a buffer space for the water vapor generated by the stack layer 34 during the evaporative cooling process, so that the steam can be discharged more smoothly through the slot 311, avoiding the impact of steam retention on the acoustic performance of the cavity.

[0076] During actual operation, when the load on the outer casing 1 is low, the piezoelectric transducer 35 of the resonant panel 3 is driven as a whole at low power to maintain basic acoustic disturbance and evaporative cooling effects. When a local hot spot is detected in the winding or core inside the outer casing 1, the corresponding piezoelectric transducer 35 unit is individually excited to form targeted enhanced acoustic disturbance, causing the liquid film of the stack layer 34 to evaporate faster in that area and quickly remove the heat from the hot spot area. Under the action of the foldback channel structure of the cavity layer 32, the acoustic standing wave intensity is further amplified, ensuring efficient heat exchange even under large heat load conditions. At the same time, the impedance adjustment mechanism formed by the back plate 33 and the secondary back cavity ensures that the entire system can maintain acoustic impedance matching and smooth steam discharge under different load conditions, ensuring long-term stable operation.

[0077] Through the arrayed partitioning drive of the piezoelectric transducer 35, the resonant panel 3 can achieve differentiated cooling according to the temperature distribution inside the housing 1, significantly improving energy utilization and effectively controlling hot spot temperature rise. The design of the cavity layer 32 with its folded-back channels enables higher acoustic standing wave intensity within a limited space, further enhancing the acoustic flow effect of the slot 311, thereby strengthening the disturbance of the air boundary layer on the surface of the heat sink 2. The combination of the backplate 33 and the secondary back cavity not only optimizes acoustic impedance but also provides a vapor buffer and smooth discharge path for the evaporation process of the stack layer 34, preventing cavity performance degradation. Overall, this embodiment achieves deep adaptation between the acoustic heat exchange system and the operating conditions of the housing 1, maintaining efficient and stable cooling performance under different load conditions. It is a high-performance cooling solution suitable for the long-term operation of new energy photovoltaic box-type transformers.

[0078] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A cooling device for a new energy photovoltaic box-type transformer, characterized in that, include: The outer casing (1) has multiple heat sinks (2) fixed on its outer side; A resonant panel (3) is fixed to the outer surface of the heat sink (2). The resonant panel (3) is arranged in the same direction as the ribs of the heat sink (2) and is tightly bonded by a thermal interface material. The resonant panel (3) includes: An open layer (31) has slit-like slots (311) evenly distributed on it. The width of the slots (311) is less than 2 mm and the length is more than 5 times the width. A cavity layer (32) is located between the opening layer (31) and the back plate (33), with a cavity depth of 2–6 mm; A stack layer (34) is disposed within the cavity layer (32), and the stack layer (34) is a hydrophilic porous material with a pore size range of 20–100 micrometers; The back plate (33) is a thin metal plate, and a piezoelectric transducer (35) is attached to the outside of the back plate (33). The piezoelectric transducer (35) is a ceramic piezoelectric sheet or a thin film piezoelectric unit. An underground condensing plate (4) is set in the soil constant temperature zone below the outer shell (1) of the box. The underground condensing plate (4) is a metal plate with a hydrophilic porous layer on its surface. The capillary tube (5) has a hydrophilic capillary core structure on the inner wall. The capillary tube (5) connects the underground condenser plate (4) to the stack layer (34) of the resonant panel (3). The capillary tube (5) is equipped with a one-way flow guide valve, which is used to guide the condensate generated by the underground condenser plate to the stack layer when the outer shell of the box is under high load during the day, and to allow the water condensed in the stack layer to flow back to the underground condenser plate when the load is low at night. The condensate adsorbed by the stack layer (34) evaporates rapidly under the action of the high-frequency sound waves generated by the piezoelectric transducer (35).

2. The cooling device according to claim 1, characterized in that, The slot (311) of the opening layer (31) is integrally formed with a micro-spiky structure (312) on the outside. The micro-spiky structure (312) is a conical protrusion with a height of less than 3 mm and a spacing of less than 10 mm. A hydrophobic isolation strip is provided between the slot (311) and the micro-spiky structure (312).

3. The cooling device according to claim 1, characterized in that, The stack layer (34) is a sintered metal foam sheet or a ceramic sintered sheet with a thickness of 0.5–2 mm.

4. The cooling device according to claim 1, characterized in that, The opening layer (31) and the groove (311) are integrally pressed and formed structures, and the chamfer radius of the two ends of the groove (311) is less than 0.5 mm.

5. The cooling device according to claim 1, characterized in that, The piezoelectric transducers (35) are arranged in an array, with each unit having a size of less than 30 mm.

6. The cooling device according to claim 1, characterized in that, The surface of the underground condenser plate (4) is coated with an aluminum oxide or silicon dioxide-based superhydrophilic coating with a thickness of less than 100 micrometers.

7. The cooling device according to claim 1, characterized in that, The cavity layer (32) of the resonant panel (3) is a folded-back channel structure, and the equivalent channel length of the folded-back channel is related to the driving frequency of the piezoelectric transducer (35) by a quarter wavelength.

8. The cooling device according to claim 1, characterized in that, A secondary back cavity is provided between the back plate (33) and the back of the cavity layer (32). The back plate (33) is a micro-perforated impedance plate, and the secondary back cavity is not connected to the outside.

9. The cooling device according to claim 1, characterized in that, The piezoelectric transducer (35) is powered by the surplus DC power from the photovoltaic power generation system to which the housing (1) belongs.

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