Photovoltaic panel self-cleaning method and photovoltaic air conditioning system

Abstract

The application provides a photovoltaic panel self-cleaning method and a photovoltaic air conditioning system. The photovoltaic panel self-cleaning method comprises the following steps: obtaining the water storage amount in a water storage tank and determining whether the water storage amount is less than a first preset water amount; if yes, spraying components at photovoltaic panel units with severe pollution are preferentially started according to the pollution degree of the photovoltaic panel units, and the spraying components spray toward the corresponding photovoltaic panel units; if no, it is determined whether the water storage amount is greater than a second preset water amount; if the water storage amount is less than or equal to the second preset water amount, the spraying components spray toward the corresponding photovoltaic panel units at a first flow rate for a first preset time; if the water storage amount is greater than the second preset water amount, the spraying components spray toward the corresponding photovoltaic panel units at a second flow rate for a second preset time; the second flow rate is greater than the first flow rate, and / or the second preset time is greater than the first preset time. The photovoltaic panel self-cleaning method can reasonably clean the photovoltaic panel according to the water storage amount in the water storage tank, and ensure the cleaning effect.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically, to a self-cleaning method for photovoltaic panels and a photovoltaic air conditioning system. Background Technology

[0002] Photovoltaic (PV) power generation is a common form of solar power generation, characterized by relatively high conversion efficiency, safety, and flexibility. The light transmittance of the PV panel surface is a crucial factor affecting PV power generation efficiency, thus requiring the maintenance of its cleanliness. Over time, dirt accumulates on the PV panel surface exposed to air, significantly reducing PV power generation efficiency. Therefore, PV surface cleaning technology is receiving increasing attention. PV surface cleaning technologies can be divided into active and passive methods. Passive technology uses a special hydrophobic coating on the PV panel surface to reduce the likelihood of dirt adhesion; however, passive technology can only reduce the frequency of dirt buildup, not completely eliminate it. Compared to passive technology, active technology is more flexible and versatile, and removes dirt more thoroughly.

[0003] Currently, cleaning photovoltaic (PV) panels mostly relies on manual labor, which significantly increases maintenance costs, especially in remote or complex areas. Self-cleaning PV panels can solve this problem, and the panels themselves can provide the power for the cleaning process. Common self-cleaning technologies require a water source or rainwater collection, but rainwater collection is unstable and unsuitable for arid regions. Summary of the Invention

[0004] The first objective of this invention is to provide a self-cleaning method for photovoltaic panels, which can clean the photovoltaic panels reasonably according to the amount of water stored in the water tank, thereby ensuring the cleaning effect.

[0005] A second objective of this invention is to provide a photovoltaic air conditioning system that implements the above-described self-cleaning method for photovoltaic panels.

[0006] To achieve the aforementioned first objective, the present invention provides a self-cleaning method for photovoltaic panels, comprising: obtaining the water volume in a water storage tank and determining whether the water volume is less than a first preset water volume; if so, prioritizing the activation of spray components at heavily contaminated photovoltaic panel units according to the degree of contamination of the photovoltaic panel units, with the spray components spraying towards the corresponding photovoltaic panel units; if not, determining whether the water volume is greater than a second preset water volume; if the water volume is less than or equal to the second preset water volume, activating the spray components at all photovoltaic panel units requiring cleaning, with the spray components spraying towards the corresponding photovoltaic panel units at a first flow rate for a first preset time; if the water volume is greater than the second preset water volume, activating the spray components at all photovoltaic panel units requiring cleaning, with the spray components spraying towards the corresponding photovoltaic panel units at a second flow rate for a second preset time; wherein the second flow rate is greater than the first flow rate, and / or the second preset time is greater than the first preset time.

[0007] As can be seen from the above scheme, if dirt and foreign objects obstruct the surface of the photovoltaic panel, reducing the area receiving sunlight, the power generation efficiency will decrease, necessitating cleaning. When the photovoltaic panel enters self-cleaning mode, if the water level in the storage tank is less than the first preset level, heavily polluted areas will be cleaned first, based on the degree of contamination of the photovoltaic panel unit. When the water level is greater than the second preset level, the water level is considered sufficient and abundant, allowing for increased water flow to achieve better cleaning intensity and / or appropriately extended cleaning time for improved cleaning results. This self-cleaning method can effectively clean photovoltaic panels even in areas with low rainfall, adjusting the cleaning based on the water level in the storage tank. For example, when the water level is low, it prioritizes cleaning heavily soiled photovoltaic panel units to maximize sunlight intensity; when the water level is sufficient, it increases the water flow and / or extends the cleaning time for better cleaning results, maximizing the area of ​​the photovoltaic panel receiving sunlight and improving power generation efficiency.

[0008] A preferred embodiment is that the photovoltaic panel self-cleaning method further includes: after completing one cleaning cycle, obtaining the light intensity E received by each cleaned photovoltaic panel unit. N+1 And determine the light intensity E N+1 Compared to the light intensity E received by the photovoltaic panel unit before cleaning N Is the difference greater than the first preset light intensity threshold ΔE? If E N+1 -E N > △E, determine if the first condition is satisfied: 0 ≤ (E) N+1 -E N ) / E N <g, where g is a preset growth rate threshold; if the first condition is met, the corresponding sprinkler component of the photovoltaic panel unit is turned off; if the first condition is not met, the process returns to the step of determining whether the water storage is less than the first preset water volume. If E N+1 -EN If the value is less than or equal to ΔE, then the corresponding spray component of the photovoltaic panel unit will be turned off.

[0009] Therefore, if E N+1 -E N If E ≤ △E, it indicates that the cleaning was ineffective, possibly because the dirt was too tightly bonded to the photovoltaic panel to be cleaned by spraying. Continuing to clean would waste water and other resources. Therefore, the corresponding spray unit can be turned off, and the corresponding photovoltaic panel unit can be cleaned manually later. If E N+1 -E N If the value is greater than ΔE, it indicates that the cleaning was effective, and the number of cleaning cycles can be increased to continue cleaning the photovoltaic panels. Additionally, after each cleaning cycle, it is checked whether the condition 0 ≤ (E / ΔE) is met. N+1 -E N ) / E N <g, which is to judge the growth rate of the light intensity received by the photovoltaic panel unit after cleaning and before cleaning. If the judgment condition is met, it means that the photovoltaic panel self-cleaning is completed and the best cost performance is achieved. Continuing to clean will not significantly improve the effect and will consume resources. If the condition is not met, it means that the cleaning effect can still be improved and cleaning can continue.

[0010] A further solution is that, in the steps of the photovoltaic panel self-cleaning method, the number of times the step of judging whether the water storage volume is less than the first preset water volume is n, n≥1, and the duration of the (n+1)th cleaning is more than the duration of the nth cleaning by a preset amount.

[0011] Therefore, it is evident that increasing the interval between cleaning sessions can improve cleaning efficiency and expedite the cleaning of photovoltaic panels.

[0012] A further option is, if E N+1 -E N If the value is less than or equal to ΔE, then in the step of shutting down the spray component corresponding to the corresponding photovoltaic panel unit, after shutting down the spray component corresponding to the corresponding photovoltaic panel unit, the position of the photovoltaic panel unit is recorded.

[0013] Therefore, by recording the cleaning cycle and cleaning time of the photovoltaic panel unit, it is easy to achieve automatic cleaning of the photovoltaic panel.

[0014] A preferred embodiment is that the photovoltaic panel self-cleaning method further includes: when the absolute value of the difference between the light intensity received by the photovoltaic panel unit and the average light intensity received by the photovoltaic panel unit under the same weather conditions in previous years is less than a second preset light intensity threshold, the step of obtaining the water storage volume in the water tank and determining whether the water storage volume is less than a first preset water volume is performed.

[0015] Therefore, by comparing the difference between the light intensity and the average light intensity under the same weather conditions in previous years, the appropriate range of the current light intensity can be determined, thereby further accurately determining whether cleaning is necessary.

[0016] A preferred approach is to turn on the fan before performing the steps of obtaining the water volume in the water tank and determining whether the water volume is less than the first preset water volume. The fan blows the debris attached to the surface of the photovoltaic panel unit into the dust collection trough at the bottom of the photovoltaic panel unit.

[0017] Therefore, by turning on the fans installed on the photovoltaic panel units, the air pressure blows the dust and other particles adhering to the surface of the photovoltaic panel units into the dust collection troughs at the bottom of the photovoltaic panel units. When the accumulation of dust and other particles in the dust collection troughs exceeds the accumulation line, they are collected and sealed to prevent the dust and other particles from adhering to the photovoltaic panels again or multiple times, thus keeping the photovoltaic panels clean. In addition, the installation of fans can first blow off some dust and other foreign objects, which can further reduce water consumption and is more suitable for arid and low-rainfall areas.

[0018] A preferred option is that the spraying component is a pulse jet.

[0019] Therefore, it can be seen that using high-pressure pulse spraying to rinse photovoltaic panels, with multiple pulse modes that can be set to meet the cleaning needs of different foreign objects and dirt, can achieve better cleaning results with less water.

[0020] A preferred embodiment is that the photovoltaic panel self-cleaning method further includes: obtaining the outdoor ambient temperature T. 外环 Indoor ambient temperature T 内环 And the weight G of the photovoltaic panel 板 When the outdoor ambient temperature is lower than the first temperature threshold and the weight of the photovoltaic panel is greater than the load-bearing protection threshold, the snow melting and defrosting step is initiated.

[0021] Therefore, when the outdoor ambient temperature is lower than the first temperature threshold and the weight of the photovoltaic panel is greater than the load-bearing protection threshold, it indicates that there is snow or frost on the photovoltaic panel in winter, which affects the photovoltaic power generation. Depending on the relative weight, the appropriate method should be selected for snow melting and defrosting to improve the problem of reduced power generation efficiency of photovoltaic panels caused by snow or dirt.

[0022] A further proposed solution involves the following steps for snow melting and defrosting: determining whether the following conditions are met: the difference between the indoor ambient temperature and the preset temperature is less than the preset temperature difference, and the weight of the photovoltaic panel is less than the weight threshold; if so, opening the return air duct towards the photovoltaic panel unit, allowing the return air duct to exhaust indoor air towards the photovoltaic panel unit; and / or opening the spray unit to spray the water from the water tank, after heat exchange with the return air duct, towards the photovoltaic panel unit; and / or if the energy storage capacity of the photovoltaic panel unit is sufficient for the photovoltaic air conditioning system to operate at increased frequency, increasing the compressor operating frequency of the photovoltaic air conditioning system and opening the return air duct towards the photovoltaic panel unit, allowing the return air duct to exhaust indoor air towards the photovoltaic panel unit; if not, activating the first heating element installed on the photovoltaic panel unit; and / or activating the second heating element installed in the water tank and opening the spray unit.

[0023] Therefore, when indoor operating conditions are stable—that is, the difference between the indoor ambient temperature and the preset temperature is less than the preset temperature difference, and the weight of the photovoltaic panel is less than the weight threshold—it indicates that there is little snow accumulation on the photovoltaic panel. Direct sunlight or indoor waste heat can meet the needs of snow melting and defrosting. The recovered indoor waste heat can be blown onto the snow layer on the photovoltaic panel for defrosting and snow melting, such as by exhausting warmer indoor air to the photovoltaic panel through a return air duct; or this waste heat can be used as a heat source for water treatment heating, heating stored water and then spraying it onto the photovoltaic panel. Furthermore, when the photovoltaic power storage is sufficient to support the photovoltaic air conditioning system's frequency increase operation, and indoor thermal comfort is satisfied, the photovoltaic air conditioning system can operate at a higher frequency to increase its heating capacity for snow melting and defrosting of the photovoltaic panel. After completion, it can then operate at the frequency corresponding to the set temperature, fully utilizing the advantages of photovoltaic power generation and improving energy utilization efficiency. Meanwhile, when the weight of the photovoltaic panel is greater than or equal to the weight threshold, it indicates that the snow on the photovoltaic panel has reached a certain thickness. Direct sunlight and indoor residual heat are insufficient to achieve rapid snow melting and defrosting. It is necessary to turn on the electric auxiliary heater to heat the surface of the photovoltaic panel, so that the snow layer and the contact surface of the photovoltaic panel melt into snow water. The heated and melted snow water has a lubricating effect, which helps the snow layer slide down the inclined surface of the photovoltaic panel. At the same time, the stored water from the water tank is heated and sprayed onto the snow to accelerate the melting of the snow.

[0024] To achieve the second objective mentioned above, the present invention provides a photovoltaic air conditioning system, which includes a processor. The processor executes a program stored in a memory to implement the photovoltaic panel self-cleaning method described above.

[0025] In a preferred embodiment, the photovoltaic air conditioning system further includes a rainwater collection unit, a condensate collection unit, and a water treatment unit; both the rainwater collection unit and the condensate collection unit are connected to the inlet of the water treatment unit, and the outlet of the water treatment unit is connected to a water storage tank.

[0026] Therefore, by collecting condensate from air conditioning dehumidification and cooling operations, water from heating and defrosting operations, and rainwater as clean water sources, the problem of unstable water collection during photovoltaic panel cleaning can be solved, enabling self-cleaning systems to be used even in arid and low-rainfall areas. Simultaneously, this improves energy efficiency, reduces personnel input, achieves intelligent management of the photovoltaic system's lifecycle, and saves on photovoltaic panel maintenance costs and complexity.

[0027] A further proposed solution is that the rainwater harvesting unit includes a photovoltaic panel drip tray located below the photovoltaic panel unit, and the condensate harvesting unit includes an air conditioning drip tray.

[0028] Therefore, rainwater can be collected through the photovoltaic panel drip tray below the photovoltaic panel unit, and condensate generated during the cooling and dehumidification operation of the air conditioner, as well as condensate generated during the defrosting of the outdoor unit of the air conditioner during the heating operation and water after cleaning the photovoltaic panel unit can be collected through the air conditioner drip tray. Attached Figure Description

[0029] Figure 1 This is a flowchart of the photovoltaic panel self-cleaning method under summer cooling conditions in the first embodiment of the photovoltaic air conditioning system of the present invention.

[0030] Figure 2 This is a flowchart of the photovoltaic panel self-cleaning method under winter heating conditions in the first embodiment of the photovoltaic air conditioning system of the present invention.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0032] Various exemplary embodiments of the invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the invention or its application or use. The invention can be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the invention thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0033] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, without excluding the possibility of encompassing other elements. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] In this invention, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0035] All terms used in this invention (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0036] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0037] Examples of photovoltaic air conditioning systems and their photovoltaic panel self-cleaning methods: See Figure 1 The photovoltaic air conditioning system in this embodiment includes a photovoltaic power generation system, an air conditioner, a cleaning system, and a processor.

[0038] The photovoltaic (PV) power generation system includes PV inverters, rectifiers, voltage regulators, and other devices for switching between AC and DC currents, as well as several PV panels for collecting solar energy. The battery system includes several energy storage battery banks, inverters, and their piping and structural components connected to the heat exchange system. The PV power generation system supplies power to each unit system, while the air conditioning and cleaning systems are responsible for collecting condensate, recovering indoor waste heat, collecting and treating stored water, and cleaning the PV panels.

[0039] Cleaning systems can be divided into two types: wind cleaning systems and water cleaning systems. Wind cleaning systems include fans installed on top of photovoltaic panels, which rely on wind pressure to blow away dust.

[0040] The water cleaning system mainly consists of a water storage tank, spray components, a water treatment unit, a rainwater collection unit, and a condensate collection unit. Both the rainwater and condensate collection units are connected to the inlet of the water treatment unit, while the outlet of the water treatment unit is connected to the water storage tank. The rainwater collection unit includes a photovoltaic panel drip tray located below the photovoltaic panel unit. The condensate collection unit includes an air conditioning drip tray, which receives condensate generated during air conditioning cooling and dehumidification operations, as well as condensate from the outdoor unit defrosting during air conditioning heating operations. The photovoltaic panel drip tray receives rainwater flowing from the photovoltaic panel unit and water used for cleaning the photovoltaic panel unit. All condensate, rainwater, and condensate are purified by the water treatment device and then sent to the water storage tank for reuse during the next cleaning cycle. The water treatment device purifies rainwater and recycles the water source used for cleaning the photovoltaic panels. The photovoltaic panel drip tray is equipped with a dust collection trough to collect dust and other debris blown off the surface of the photovoltaic panel unit by the fan.

[0041] Preferably, the spraying component is a pulse jet sprayer. The pulse jet sprayer uses high-pressure pulses to rinse the photovoltaic panels. It allows water from the storage tank to be ejected at a preset frequency in a high-pressure pulse pattern, effectively cleaning the surface of the photovoltaic panel units while conserving water. Furthermore, multiple pulse patterns can be set to meet the cleaning needs of different types of foreign objects and dirt, achieving better cleaning results with less water. Each pulse jet sprayer for each photovoltaic panel unit can also adjust its spray angle, with the spray range extending from the left to the right top edge of the corresponding photovoltaic panel unit. This ensures that the high-pressure water stream cleans the surface of each photovoltaic panel unit, meeting its cleaning requirements.

[0042] The processor is used to execute a program stored in memory to implement a self-cleaning method for photovoltaic panels.

[0043] See Figure 1 Under summer cooling conditions, the self-cleaning method for photovoltaic panels includes the following steps: First, step S101 is executed to determine whether the absolute value of the difference between the solar irradiance E1 received by the photovoltaic panel unit and the average solar irradiance E2 received by the photovoltaic panel unit under the same weather conditions in previous years is less than a second preset solar irradiance threshold. If so, it indicates that the surface of the photovoltaic panel is blocked by dirt or other foreign objects. Then, step S102 is executed to turn on the fan. The fan uses wind pressure to blow the dust and particulate matter attached to the surface of the photovoltaic panel unit to the dust collection trough at the bottom of the photovoltaic panel unit. The average solar irradiance under the same weather conditions in previous years is obtained by recording the average solar irradiance from sunrise to sunset every day over the past few years. At the same time, the data can be entered into a database and updated in real time. The photovoltaic panel angle and the shading coefficient of the photovoltaic panel in the current quarter are recorded. The system uses this data to prioritize adjusting to the optimal photovoltaic panel angle for the current quarter to obtain the maximum light projection. In addition, the same weather conditions in previous years are not necessarily the same day in previous years, but can be any day in the same quarter in previous years. Also, on rainy days, rainwater will wash the photovoltaic panel to achieve a cleaning effect. The judgment condition here is for non-rainy weather.

[0044] Next, step S1 is executed to obtain the water volume in the water tank and determine whether the water volume is less than the first preset water volume.

[0045] If so, proceed to step S11: based on the degree of contamination of the photovoltaic panel unit, prioritize activating the spray components at the heavily contaminated photovoltaic panel units, with the spray components spraying towards the corresponding photovoltaic panel unit. The degree of contamination of the photovoltaic panel unit can be determined by the light intensity received by the photovoltaic panel unit.

[0046] If not, proceed to step S12 to determine whether the water storage volume is greater than the second preset water volume.

[0047] If the water storage volume is less than or equal to the second preset water volume, then step S121 is executed, and the spray components at all photovoltaic panel units that need to be cleaned are turned on, and the spray components spray the corresponding photovoltaic panel units at a first flow rate for a first preset time.

[0048] If the water storage volume is greater than the second preset water volume, then step S122 is executed, activating the spray components at all photovoltaic panel units that need cleaning. The spray components spray the corresponding photovoltaic panel units at a second flow rate for a second preset time. The second flow rate is greater than the first flow rate, and / or the second preset time is greater than the first preset time. That is, when the water storage volume is greater than the second preset water volume, it indicates that the water storage tank has sufficient and abundant water. A better cleaning effect can be obtained by increasing the output water flow rate or appropriately increasing the cleaning time, or by simultaneously increasing the output water flow rate and appropriately increasing the cleaning time.

[0049] After completing one cleaning cycle, proceed to step S2 to obtain the light intensity E received by each cleaned photovoltaic panel unit. N+1 And determine the light intensity EN+1 Compared to the light intensity E received by the photovoltaic panel unit before cleaning N Is the difference greater than the first preset light intensity threshold △E?

[0050] If E N+1 -E N If the value is greater than △E, it means the cleaning was effective. Then proceed to step S21 and determine if the first condition is met: 0 ≤ (E). N+1 -E N ) / E N <g, where g is the preset growth rate threshold.

[0051] If the first condition is met, it indicates that the photovoltaic panel self-cleaning is complete, achieving the best cost-effectiveness. Continuing cleaning will not significantly improve the effect and will consume resources. In this case, step S211 is executed to shut down the spray component corresponding to the photovoltaic panel unit. After cleaning, the cleaning cycle and cleaning time of the photovoltaic panel unit are recorded and updated. By organizing the cleaning cycle, the weather and pollution conditions of the corresponding quarter and the degree of dirt accumulation are obtained. The system can adaptively adjust the cleaning frequency, cleaning duration, and number of cleanings.

[0052] If the first condition is not met, return to step S1.

[0053] If E N+1 -E N If the value is ≤△E, it indicates that the cleaning was ineffective, possibly because the dirt was too tightly bonded to the photovoltaic panel to be cleaned by spraying. Continuing to clean would waste water and other resources. Therefore, step S22 is executed to shut down the spray component corresponding to the photovoltaic panel unit and record the location of the photovoltaic panel unit. The corresponding photovoltaic panel unit can be cleaned manually later. Specifically, a visual monitoring system can be established. The system marks the photovoltaic panel units that have been cleaned and their cleaning time, and marks the photovoltaic panel units that have not been cleaned or have failed to self-clean, displaying red dots on the monitor to facilitate subsequent maintenance of the photovoltaic panels.

[0054] In the self-cleaning method for photovoltaic panels, the number of times step S1 is returned is n, where n≥1, and the duration of the (n+1)th cleaning is longer than the duration of the nth cleaning by a preset time. Preferably, the preset time is 1 minute.

[0055] See Figure 2 Under winter cooling conditions, the self-cleaning method for photovoltaic panels includes the following steps: First, execute step S201 to obtain the outdoor ambient temperature T. 外环 Indoor ambient temperature T 内环 And the weight G of the photovoltaic panel 板 When the outdoor ambient temperature T 外环The temperature is less than the first temperature threshold T1, and the weight G of the photovoltaic panel is... 板 Greater than the load-bearing protection threshold G 阈值 If the snow accumulation or frost on the photovoltaic panel is detected, it indicates that there is snow accumulation or frost on the surface in winter, which affects the photovoltaic power generation. Based on the relative weight, the appropriate method is selected for snow melting and defrosting. At the same time, it is necessary to prevent excessive snow accumulation from causing excessive stress on the photovoltaic panel support structure. When the outdoor ambient temperature is lower than the first temperature threshold and the weight of the photovoltaic panel is greater than the load-bearing protection threshold, the snow melting and defrosting step S3 is initiated.

[0056] Step S3, determine whether the following condition is met: indoor ambient temperature T 内环 With preset temperature T 预设 The difference is less than the preset temperature difference ΔT, and the weight G of the photovoltaic panel is less than the preset temperature difference ΔT. 板 Less than the weight threshold G 阈值 Preset temperature T 预设 The temperature is set by the user via remote control or other means.

[0057] If so, it indicates that the indoor operating conditions are stable and there is little snow accumulation on the photovoltaic panels. Direct sunlight or indoor waste heat can meet the needs of snow melting and defrosting. Then, proceed to step S31: open the return air duct towards the photovoltaic panel unit, and the return air duct will exhaust the hot indoor air towards the photovoltaic panel unit, thereby utilizing the recovered indoor waste heat for defrosting and snow melting; and / or open the spray unit to spray the water in the water tank that has exchanged heat with the return air duct towards the photovoltaic panel unit; and / or if the energy storage capacity of the photovoltaic panel unit is sufficient for the photovoltaic air conditioning system to operate at increased frequency, when indoor thermal comfort is satisfied, the operating frequency of the compressor of the photovoltaic air conditioning system can be increased to increase its heating capacity for snow melting and defrosting of the photovoltaic panels. The return air duct towards the photovoltaic panel unit will be opened, and the return air duct will exhaust the indoor air towards the photovoltaic panel unit. After completion, the compressor operating frequency will be reduced back to the previous frequency to fully utilize the advantages of photovoltaic power generation and improve energy utilization.

[0058] If not, it indicates that the snow accumulation on the photovoltaic panel has reached a certain thickness, and direct sunlight and indoor residual heat are insufficient for rapid snow melting and defrosting. In this case, step S32 is executed to activate the first heating component located on the back of the photovoltaic panel unit; and / or activate the second heating component located in the water storage tank and turn on the spray system. This melts the snow on the contact surface between the snow layer and the photovoltaic panel into melted snow water. The heated melted snow water acts as a lubricant, facilitating the snow layer to slide down the inclined surface of the photovoltaic panel. Simultaneously, the stored water from the water storage tank is heated and sprayed onto the snow, accelerating its melting. The first and second heating components can be electric heaters.

[0059] Next, step S101 is executed to determine whether the absolute value of the difference between the light intensity E1 received by the photovoltaic panel unit and the average light intensity E2 received by the photovoltaic panel unit under the same weather conditions in previous years is less than the second preset light intensity threshold. If so, step S102 is executed to turn on the fan and blow the debris attached to the surface of the photovoltaic panel unit into the dust accumulation trough at the bottom of the photovoltaic panel unit.

[0060] Next, step S1 is executed to obtain the water volume in the water tank and determine whether the water volume is less than the first preset water volume.

[0061] If so, proceed to step S11, whereby, based on the degree of contamination of the photovoltaic panel unit, the spray component at the heavily contaminated photovoltaic panel unit is activated first, and the spray component sprays water towards the corresponding photovoltaic panel unit. Preferably, the spray component is a pulse jet sprayer.

[0062] If not, proceed to step S12 to determine whether the water storage volume is greater than the second preset water volume.

[0063] If the water storage volume is less than or equal to the second preset water volume, then step S121 is executed, and the spray components at all photovoltaic panel units that need to be cleaned are turned on, and the spray components spray the corresponding photovoltaic panel units at a first flow rate for a first preset time.

[0064] If the water storage capacity is greater than the second preset water volume, then step S122 is executed, activating the spray components at all photovoltaic panel units that need cleaning. The spray components spray the corresponding photovoltaic panel units at a second flow rate for a second preset time. The second flow rate is greater than the first flow rate, and / or the second preset time is greater than the first preset time.

[0065] After completing one cleaning cycle, proceed to step S2 to obtain the light intensity E received by each cleaned photovoltaic panel unit. N+1 And determine the light intensity E N+1 Compared to the light intensity E received by the photovoltaic panel unit before cleaning N Is the difference greater than the first preset light intensity threshold △E?

[0066] If E N+1 -E N If the value is greater than △E, it means the cleaning was effective. Then proceed to step S21 and determine if the first condition is met: 0 ≤ (E). N+1 -E N ) / E N <g, where g is the preset growth rate threshold.

[0067] If the first condition is met, it indicates that the photovoltaic panel self-cleaning is complete, achieving the best cost-effectiveness. Continuing cleaning will not significantly improve the effect and will consume resources. In this case, proceed to step S211 to shut down the spray component corresponding to the photovoltaic panel unit. After cleaning is completed, record and update the cleaning cycle and cleaning time of the photovoltaic panel unit.

[0068] If the first condition is not met, return to step S1.

[0069] If E N+1 -E N If the value is less than or equal to △E, it means that the cleaning is ineffective. This may be because the dirt is too tightly bonded to the photovoltaic panel to be cleaned by spraying. Continuing to clean would waste water and other resources. Therefore, step S22 is executed to turn off the spray component corresponding to the photovoltaic panel unit and record the position of the photovoltaic panel unit. The corresponding photovoltaic panel unit can be cleaned manually later.

[0070] In the steps of the photovoltaic panel self-cleaning method, the number of times step S6 is returned is n, n≥1, and the duration of the (n+1)th cleaning is longer than the duration of the nth cleaning by a preset time. Preferably, the preset time is 1 minute.

[0071] As can be seen from the above, this self-cleaning method for photovoltaic panels can clean the photovoltaic panels reasonably according to the water storage tank, even in areas with little rain. For example, when the water storage is low, it prioritizes cleaning the photovoltaic panel units with more dirt to maximize the increase in light intensity. When the water storage is sufficient, it increases the water flow and / or increases the cleaning time to obtain a better cleaning effect, thereby maximizing the area of ​​the photovoltaic panel that receives sunlight and improving power generation efficiency.

[0072] In addition, in other embodiments, an infrared ranging sensor can be installed on the photovoltaic panel to detect the presence of foreign objects. For example, the infrared transmitter and receiver of the infrared ranging sensor can be positioned on opposite sides of the photovoltaic panel, with both at the same distance from the surface of the photovoltaic panel. When the accumulation of foreign objects on the photovoltaic panel exceeds a preset thickness, it will block the infrared light, thereby detecting the thickness of the foreign objects on the photovoltaic panel. Furthermore, steps S102 and S5 of turning on the fan can be omitted. A detection device for detecting the amount of debris accumulation can also be installed in the ash collection trough. When the accumulation of dust and particulate matter in the ash collection trough exceeds the accumulation line, it is centrally sealed to prevent secondary or multiple adhesion of dust and particulate matter to the photovoltaic panel, keeping the photovoltaic panel clean. Furthermore, a water pump can be installed on the pipeline between the water treatment unit and the water storage tank to provide the power for water flow. Alternatively, a first heating element can be installed only on the photovoltaic panel unit, or a second heating element can be installed only in the water storage tank. These modifications can also achieve the objectives of the present invention.

[0073] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-cleaning method for photovoltaic panels, characterized in that, include: Obtain the water volume in the water storage tank and determine whether the water volume is less than a first preset water volume; If so, then based on the degree of pollution of the photovoltaic panel unit, the spray component at the heavily polluted photovoltaic panel unit will be activated first, and the spray component will spray towards the corresponding photovoltaic panel unit; If not, determine whether the water storage capacity is greater than the second preset water volume; If the water storage capacity is less than or equal to the second preset water volume, then the spray components at all photovoltaic panel units that need to be cleaned are turned on, and the spray components spray the corresponding photovoltaic panel units at a first flow rate for a first preset time. If the water storage capacity is greater than the second preset water volume, then the spray components at all photovoltaic panel units that need to be cleaned are activated, and the spray components spray the corresponding photovoltaic panel units at a second flow rate for a second preset time. The second flow rate is greater than the first flow rate, and / or the second preset time is greater than the first preset time; The self-cleaning method for photovoltaic panels also includes: After one cleaning cycle, the light intensity E received by each cleaned photovoltaic panel unit is obtained. N+1 And determine the light intensity E N+1 Compared to the light intensity E received by the photovoltaic panel unit before cleaning N Is the difference greater than the first preset light intensity threshold △E? If E N+1 -E N > △E, determine if the first condition is satisfied: 0 ≤ (E) N+1 -E N ) / E N <g, where g is the preset growth rate threshold; If the first condition is met, then the spray component corresponding to the photovoltaic panel unit is turned off; If the first condition is not met, return to the step of determining whether the water storage volume is less than the first preset water volume; If E N+1 -E N If the value is less than or equal to ΔE, then the corresponding spray component of the photovoltaic panel unit will be turned off.

2. The self-cleaning method for photovoltaic panels according to claim 1, characterized in that: In the steps of the photovoltaic panel self-cleaning method, the number of times the step of judging whether the water storage volume is less than the first preset water volume is n, n≥1, and the duration of the (n+1)th cleaning is more than the duration of the nth cleaning by a preset time.

3. The photovoltaic panel self-cleaning method according to claim 1, characterized in that: If E N+1 -E N If the value is less than or equal to ΔE, then in the step of shutting down the spray component corresponding to the corresponding photovoltaic panel unit, after shutting down the spray component corresponding to the corresponding photovoltaic panel unit, the position of the photovoltaic panel unit is recorded.

4. The self-cleaning method for photovoltaic panels according to any one of claims 1 to 3, characterized in that: The photovoltaic panel self-cleaning method further includes: when the absolute value of the difference between the light intensity received by the photovoltaic panel unit and the average light intensity received by the photovoltaic panel unit under the same weather conditions in previous years is less than a second preset light intensity threshold, the step of obtaining the water storage volume in the water tank and determining whether the water storage volume is less than a first preset water volume is executed.

5. The photovoltaic panel self-cleaning method according to any one of claims 1 to 3, characterized in that: Before performing the steps of obtaining the water storage volume in the water tank and determining whether the water storage volume is less than the first preset water volume, the fan is turned on first. The fan blows the debris attached to the surface of the photovoltaic panel unit into the dust accumulation trough at the bottom of the photovoltaic panel unit.

6. The photovoltaic panel self-cleaning method according to any one of claims 1 to 3, characterized in that: The spraying component is a pulse jet injector.

7. The photovoltaic panel self-cleaning method according to any one of claims 1 to 3, characterized in that: The self-cleaning method for photovoltaic panels also includes: The system acquires the outdoor ambient temperature, indoor ambient temperature, and the weight of the photovoltaic panel. When the outdoor ambient temperature is lower than the first temperature threshold and the weight of the photovoltaic panel is greater than the load-bearing protection threshold, it enters the snow melting and defrosting step.

8. The self-cleaning method for photovoltaic panels according to claim 7, characterized in that: The snow melting and defrosting steps include: Determine if the following conditions are met: the difference between the indoor ambient temperature and the preset temperature is less than the preset temperature difference, and the weight of the photovoltaic panel is less than the weight threshold. If so, open the return air duct towards the photovoltaic panel unit, the return air duct exhausts indoor air towards the photovoltaic panel unit; and / or open the spray unit to spray the water in the water tank after heat exchange with the return air duct towards the photovoltaic panel unit; and / or if the power storage capacity of the photovoltaic panel unit is sufficient for the photovoltaic air conditioning system to operate at increased frequency, increase the compressor operating frequency of the photovoltaic air conditioning system, and open the return air duct towards the photovoltaic panel unit, the return air duct exhausts indoor air towards the photovoltaic panel unit; If not, then activate the first heating element installed on the photovoltaic panel unit; and / or activate the second heating element installed in the water storage tank and turn on the spray unit.

9. A photovoltaic air conditioning system, characterized in that: The photovoltaic air conditioning system includes a processor, which executes a program stored in a memory to implement the photovoltaic panel self-cleaning method as described in any one of claims 1 to 8.

10. The photovoltaic air conditioning system according to claim 9, characterized in that: The photovoltaic air conditioning system also includes a rainwater collection unit, a condensate collection unit, and a water treatment unit; Both the rainwater collection unit and the condensate collection unit are connected to the inlet of the water treatment unit, and the outlet of the water treatment unit is connected to the water storage tank.

11. The photovoltaic air conditioning system according to claim 10, characterized in that: The rainwater collection unit includes a photovoltaic panel water collection tray located below the photovoltaic panel unit, and the condensate collection unit includes an air conditioner water collection tray.

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