Photovoltaic photo-thermal system and control method thereof

Abstract

The invention relates to a photovoltaic photo-thermal system and a control method thereof.The photovoltaic photo-thermal system comprises a heat collection module used for achieving heat collection, and the heat collection module comprises a photovoltaic photo-thermal plate, a hydrothermal module used for conducting heat exchange with the heat collection module to obtain hot water and a data collection module used for collecting photovoltaic state data of the photovoltaic photo-thermal plate; the system further comprises a cleaning module used for communicating hot water to the photovoltaic photo-thermal plate under the condition that it is determined that cleaning needs to be carried out based on photovoltaic state data, dust and pollutants accumulated on the photovoltaic photo-thermal plate can be effectively cleaned, the photoelectric conversion efficiency of the photovoltaic photo-thermal plate is improved, abrasion and corrosion of the plate face can be reduced, the service life of the photovoltaic photo-thermal plate is prolonged, and the energy consumption of the photovoltaic photo-thermal plate is reduced. Due to the automatic cleaning function, the requirement for manual intervention is reduced, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of solar energy utilization, and in particular to a photovoltaic thermal system and a control method thereof. Background Art

[0002] As the demand for energy conservation and emission reduction increases, photovoltaic power generation, as one of the common solar power generation methods, has the advantages of relatively high conversion efficiency, safety and flexibility, and has been widely valued by countries around the world. The core component of photovoltaic power generation is the photovoltaic thermal panel, which mainly generates electricity by absorbing solar energy and converting it into electrical energy. Therefore, the light transmittance of the photovoltaic thermal panel surface is an important factor affecting the efficiency of photovoltaic power generation, and it is particularly important to maintain the cleanliness of its surface.

[0003] However, during long-term use, photovoltaic thermal panels will inevitably accumulate dust and other pollutants, which not only affects the light absorption efficiency, but also reduces the overall performance of the photovoltaic thermal system. Summary of the invention

[0004] Based on this, it is necessary to provide a photovoltaic thermal system and a control method thereof that can automatically clean the photovoltaic thermal panels in order to address the technical problem of the accumulation of pollutants in the photovoltaic thermal panels after long-term use.

[0005] A photovoltaic thermal system, comprising:

[0006] A heat collection module including a photovoltaic thermal panel is used to collect heat;

[0007] A hydrothermal module, used for performing heat exchange with the heat collection module to obtain hot water;

[0008] A data acquisition module, used to collect photovoltaic status data of the photovoltaic thermal panel;

[0009] A cleaning module is used to connect the hot water to the photovoltaic thermal panel when it is determined based on the photovoltaic status data that cleaning is required.

[0010] In one embodiment, the heat collection module further includes a heat exchanger, and a refrigerant circuit is connected between the photovoltaic thermal panel and the heat exchanger.

[0011] In one embodiment, the hydrothermal module includes a water tank and a hot water pump, the water tank is connected to a hot water circuit, and the hot water pump is arranged in the hot water circuit;

[0012] The hot water circuit and the refrigerant circuit exchange heat in the heat exchanger.

[0013] In one of the embodiments, a three-way valve is further included, and the cleaning module includes a water spray device and a cleaning water valve;

[0014] The water outlet of the water tank is connected to the hot water circuit through the first water outlet of the three-way valve, and is also connected to the water spray device through the second water outlet of the three-way valve. The clean water valve is arranged on the water path from the three-way valve to the water spray device.

[0015] In one embodiment,

[0016] The data acquisition module is also used to collect hot water status data in the water tank;

[0017] The cleaning module is further used to connect the hot water to the photovoltaic thermal panel when it is determined that cleaning is required based on the photovoltaic status data and the hot water status data.

[0018] In one embodiment, the data acquisition module includes a pollutant sensor and a temperature sensor. The pollutant sensor is arranged at the photovoltaic thermal panel, and the temperature sensor is arranged at the water outlet of the water tank.

[0019] In one embodiment, the thermal collection module also includes a gas-liquid separator, a compressor, an expander and a liquid reservoir. The photovoltaic thermal panel, the gas-liquid separator, the compressor, the heat exchanger, the expander and the liquid reservoir are connected in sequence through pipelines to form the refrigerant circuit.

[0020] In one embodiment, a control method of a photovoltaic thermal system is provided, which is applied to the photovoltaic thermal system as described in any of the above embodiments, and the method includes:

[0021] Obtain photovoltaic status data of photovoltaic thermal panels;

[0022] When it is determined based on the photovoltaic status data that cleaning is required, the cleaning module is started to connect the hot water of the hydrothermal module to the photovoltaic thermal panel.

[0023] In one embodiment, the method further comprises:

[0024] Get the hot water status data in the water tank;

[0025] In the case where it is determined based on the photovoltaic state data that cleaning is required, starting the cleaning module to connect the hot water of the hydrothermal module to the photovoltaic thermal panel includes:

[0026] When it is determined that cleaning is required based on the photovoltaic status data and the hot water status data, the cleaning module is started to connect the hot water of the hydrothermal module to the photovoltaic thermal panel.

[0027] In one embodiment, the photovoltaic status data includes pollution level, and the hot water status data includes hot water temperature;

[0028] The determining that cleaning is required based on the photovoltaic status data and the hot water status data includes:

[0029] When the pollution degree is greater than a preset pollution degree and the hot water temperature is greater than a preset water temperature, it is determined that cleaning is required.

[0030] The above-mentioned photovoltaic thermal system and its control method include a heat collecting module for realizing heat collection, which includes a photovoltaic thermal panel, a hydrothermal module for performing heat exchange with the heat collecting module to obtain hot water, a data acquisition module for collecting photovoltaic status data of the photovoltaic thermal panel, and a cleaning module for connecting hot water to the photovoltaic thermal panel when it is determined based on the photovoltaic status data that cleaning is required. The system can effectively clean dust and pollutants accumulated on the photovoltaic thermal panel, improve the photoelectric conversion efficiency of the photovoltaic thermal panel, reduce wear and corrosion on the panel surface, and extend the service life of the photovoltaic thermal panel. The automatic cleaning function also reduces the need for manual intervention and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of a system block diagram of a photovoltaic thermal system in one embodiment;

[0033] Figure 2 A schematic diagram of a system block diagram of a photovoltaic thermal system in another embodiment;

[0034] Figure 3 A schematic diagram of a system block diagram of a photovoltaic thermal system in yet another embodiment;

[0035] Figure 4 A schematic diagram of a system block diagram of a photovoltaic thermal system in yet another embodiment;

[0036] Figure 5 A schematic diagram of a system block diagram of a photovoltaic thermal system in another embodiment;

[0037] Figure 6 A schematic flow chart of a control method for a photovoltaic thermal system in one embodiment;

[0038] Figure 7 is a schematic flow chart of a control method for a photovoltaic thermal system in yet another embodiment;

[0039] Figure 8 A schematic diagram of the structure of a photovoltaic thermal system in one embodiment;

[0040] Fig. 9 It is a flowchart of a control method of a photovoltaic thermal system in yet another embodiment. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments of the present application are given in the accompanying drawings, but the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0042] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0043] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0044] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least part of an element” means part or all of an element.

[0045] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0047] In an exemplary embodiment, Figure 1 As shown, a photovoltaic thermal system is provided, including: a heat collection module 110 including a photovoltaic thermal panel 111, for realizing heat collection; a hydrothermal module 120, for performing heat exchange with the heat collection module 110 to obtain hot water; a data acquisition module 130, for collecting photovoltaic status data of the photovoltaic thermal panel 111; and a cleaning module 140, for connecting hot water to the photovoltaic thermal panel 111 when it is determined based on the photovoltaic status data that cleaning is required.

[0048] Specifically, the heat collection module 110 is a module that converts solar energy into electrical energy based on photovoltaic thermal panels, and can also convert the waste heat generated in the process into thermal energy. The heat collection module 110 can be specifically implemented by photovoltaic / thermal (PVT) technology, which is a new type of solar energy utilization method that integrates power generation and heat collection. On the basis of photovoltaic power generation, the waste heat generated by photovoltaic panels is recovered at the same time to achieve solar energy cogeneration. Not only does it improve the utilization efficiency of solar energy, but it also reduces the temperature of the photovoltaic thermal panel 111, thereby improving the power generation efficiency and extending the service life of the photovoltaic thermal panel 111. In the PVT technology, there is a photovoltaic part that converts solar energy into electrical energy, and a heat dissipation part that converts the waste heat generated during the operation of the photovoltaic thermal panel into thermal energy. The heat collection module 110 mentioned in this application mainly corresponds to the above-mentioned heat dissipation part.

[0049] According to different cooling technologies, the heat collection module 110 can adopt different specific structures to realize the heat collection function, for example, it can generally be divided into two types: liquid cooling and air cooling. Among them, the liquid cooling method usually uses water or refrigerant as the cooling medium, and transfers heat to the cooling medium through the heat transfer pipe to realize heat recovery. The air cooling method usually uses gas (such as air) as the cooling medium in the heat transfer pipe, and then adjusts the cooling effect by controlling the gas circulation speed in the heat transfer pipe.

[0050] Furthermore, the hydrothermal module 120 is a module for collecting heat to obtain hot water. Specifically, heat exchange can be performed with the heat collection module 110 to use the heat collected by the heat collection module 110 as a heat source for heating water to obtain hot water. The hydrothermal module 120 may include a water flow pipeline, and the water flow pipeline may be arranged close to the heat collection module 110 to achieve effective heat exchange. The hot water generated by the hydrothermal module 120 can be used for heating and domestic hot water, for example, it can be suitable for rural heating, independent building heating and other scenarios.

[0051] It is understandable that since the photovoltaic thermal panel 111 is exposed to the outdoor environment for a long time, dust and other pollutants will inevitably accumulate during operation, which will lead to a significant decrease in the efficiency of photoelectric conversion and photothermal conversion. The cleaning module 140 can be used to connect to the hydrothermal module 120 and transmit the hot water generated by the hydrothermal module 120 to the photovoltaic thermal panel 111 to achieve self-cleaning of pollutants accumulated on the surface of the photovoltaic thermal panel 111. It is understandable that the cleaning module 140 can be a device fixedly arranged at the upper end of the photovoltaic thermal panel 111 to spray water to clean the photovoltaic thermal panel 111, or it can be a cleaning device that can reciprocate on the surface of the photovoltaic thermal panel 111, or it can be a spray device that can spray a liquid with a detergent. As long as it is a device that can achieve self-cleaning of the surface of the photovoltaic thermal panel 111, it can be used as the cleaning module 140 in this embodiment.

[0052] It can be understood that since the contaminants on the photovoltaic thermal panel 111 are the result of time accumulation, the cleaning module 140 can be started on demand to clean the photovoltaic thermal panel 111. The cleaning module 140 can start cleaning the photovoltaic thermal panel 111 at a fixed time interval, or it can collect photovoltaic status data of the photovoltaic thermal panel 111 and determine when to start cleaning the photovoltaic thermal panel 111 based on the photovoltaic status data.

[0053] Furthermore, in order to effectively determine when to start cleaning the photovoltaic thermal panel 111, the photovoltaic state data of the photovoltaic thermal panel 111 can be collected through the data acquisition module 130. Among them, the type of photovoltaic state data of the photovoltaic thermal panel 111 is not unique. For example, the photovoltaic state data may include the degree of pollution of the photovoltaic thermal panel 111, the light intensity received by the photovoltaic thermal panel 111, the relevant parameter information of the photovoltaic thermal panel 111 in the process of power generation and heat collection, and the weight of the photovoltaic thermal panel 111. It can be understood that after the accumulation of pollutants on the surface of the photovoltaic thermal panel 111, the light intensity, power generation and heat collection efficiency, and weight that can be received will change, which can be used to determine whether the photovoltaic thermal panel 111 needs to be cleaned. Among them, the degree of pollution of the photovoltaic thermal panel 111 can most directly and accurately feedback whether the surface of the photovoltaic thermal panel 111 accumulates pollutants. Therefore, the embodiment of the present application uses the degree of pollution of the photovoltaic thermal panel 111 as the photovoltaic state data.

[0054] After the photovoltaic status data is detected, if it is determined that cleaning is required based on the photovoltaic status data, the cleaning module 140 can be controlled to connect hot water to the photovoltaic thermal panel 111 to achieve self-cleaning of the photovoltaic thermal panel 111. In the case where the pollution degree of the photovoltaic thermal panel 111 is used as the photovoltaic status data, a preset pollution degree can be set as a judgment threshold, that is, when the pollution degree of the photovoltaic thermal panel 111 is greater than the preset pollution degree, the cleaning module 140 is controlled to connect hot water to the photovoltaic thermal panel 111 to achieve self-cleaning of the photovoltaic thermal panel 111.

[0055] The above-mentioned photovoltaic thermal system includes a heat collecting module for realizing heat collection, which includes a photovoltaic thermal panel, a hydrothermal module for performing heat exchange with the heat collecting module to obtain hot water, a data acquisition module for collecting photovoltaic status data of the photovoltaic thermal panel, and also includes a cleaning module for connecting hot water to the photovoltaic thermal panel when it is determined based on the photovoltaic status data that cleaning is required. The module can effectively clean the dust and pollutants accumulated on the photovoltaic thermal panel, improve the photoelectric conversion efficiency of the photovoltaic thermal panel, reduce the wear and corrosion of the panel surface, and extend the service life of the photovoltaic thermal panel. The automatic cleaning function also reduces the need for manual intervention and reduces maintenance costs.

[0056] In an exemplary embodiment, Figure 2 As shown, the heat collection module 110 further includes a heat exchanger 112 , and a refrigerant circuit is connected between the photovoltaic thermal panel 111 and the heat exchanger 112 .

[0057] It can be understood that in the embodiments of the present application, the solar collector module 110 implemented by liquid cooling is used as an example for explanation, and then by connecting the refrigerant circuit between the photovoltaic thermal panel 111 and the heat exchanger 112, and circulating the refrigerant in the refrigerant circuit as a cooling medium, the waste heat generated by the photovoltaic thermal panel 111 is transferred to the refrigerant circulating therein through the refrigerant circuit, thereby realizing heat recovery.

[0058] Specifically, the refrigerant in the refrigerant circuit can absorb heat at the photovoltaic thermal panel 111, and then flow to the heat exchanger 112 to exchange the absorbed heat, thereby realizing heat reuse.

[0059] The heat exchanger 112 is a device that can realize heat exchange, and the types of devices that can be used are not unique and are not limited in this embodiment. For example, according to different heat transfer principles, it can be a plate heat exchanger or a fin heat exchanger, etc.; according to different heat transfer elements, it can be a single-pass, double-pass, multi-pass, etc. type of heat exchanger.

[0060] Exemplarily, the heat exchanger 112 used in the present application is a condenser. It can be understood that the condenser can convert gas or vapor into liquid to quickly transfer the heat in the tube to the air near the tube. Since the refrigerant will evaporate into a gaseous state after absorbing the waste heat generated by the photovoltaic thermal panel 111, the condenser is used as the heat exchanger 112 to quickly convert the gaseous refrigerant into a liquid state, and at the same time efficiently exchange the heat to achieve heat reuse.

[0061] In an exemplary embodiment, referring to Figure 2 The hydrothermal module 120 includes a water tank 121 and a hot water pump 122 . The water tank 121 is connected to a hot water circuit, and the hot water pump 122 is arranged in the hot water circuit. The hot water circuit and the refrigerant circuit perform heat exchange in the heat exchanger 112 .

[0062] Specifically, the water tank 121 is used to store the hot water obtained by heat exchange, and a heat preservation layer may be provided on the outside thereof to prevent the heat loss of the hot water. The water tank 121 may include a water inlet and a water outlet. The water inlet may be connected to the heat exchanger 112 through a hot water circuit for accessing the hot water obtained by heat exchange. The water outlet may be connected to the user side through a pipeline for heating and domestic hot water, for example, it may be applicable to rural heating, independent building heating and other scenarios. In addition, the water outlet may also be connected to the heat exchanger 112 through a hot water circuit to circulate the hot water stored in the water tank to the heat exchanger 112 to ensure that the temperature of the hot water stored therein is hot enough.

[0063] The hot water circuit and the refrigerant circuit can exchange heat in the heat exchanger 112. Taking the heat exchanger 112 as a condenser, for example, after absorbing the waste heat generated by the photovoltaic thermal panel 111, the refrigerant will evaporate into a gaseous state, and flow to the condenser through the refrigerant circuit, where the gaseous refrigerant is quickly converted into a liquid state. At the same time, the generated heat is quickly transferred to the hot water circuit arranged close to the refrigerant circuit, and the water flowing in the hot water circuit is heated into hot water, so that the heat is reused.

[0064] Furthermore, the hot water pump 122 may be disposed on a hot water circuit whose water inlet is connected to the heat exchanger 112, or may be disposed on a hot water circuit whose water outlet is connected to the heat exchanger 112. It is understood that the hot water pump 122 may be used to transport liquid in the hot water circuit, and may also increase the pressure of the liquid in the hot water circuit, thereby achieving the purpose of pumping liquid. The hot water pump 122 may be implemented by a variety of devices, such as a centrifugal pump, an electric pump, and an electromagnetic pump, and may be selected according to the actual need for transporting liquid.

[0065] Exemplarily, the water outlet of the water tank 121 is connected to the hot water circuit of the heat exchanger 112, and may also be connected to a water inlet waterway, and an inlet water valve may also be provided on the water inlet waterway to obtain external water supply when the water in the water tank 121 is insufficient.

[0066] In an exemplary embodiment, Figure 3 As shown, the above-mentioned photovoltaic thermal system also includes a three-way valve 150, and the cleaning module 140 includes a water spray device 141 and a cleaning water valve 142; the water outlet of the water tank 121 is connected to the hot water circuit through the first water outlet of the three-way valve 150, and is also connected to the water spray device 141 through the second water outlet of the three-way valve 150, and the cleaning water valve 142 is arranged on the water path connected from the three-way valve 150 to the water spray device 141.

[0067] It can be understood that the hot water obtained by the heat exchange in the present application can be used for heating and domestic hot water needs, and can also be used to self-clean the photovoltaic thermal panel 111 through the cleaning module 140.

[0068] Specifically, in order to reduce the cost of cleaning the photovoltaic thermal panel 111, the water spray device 141 can be implemented by a micro water spray device. The micro water spray device generally refers to a small, low-cost and easy-to-operate water spray device, which can be an electric sprayer or a pneumatic sprayer.

[0069] Furthermore, the water spray device 141 of this embodiment may include a cleaning water pipe fixed to the upper eaves of the photovoltaic thermal panel 111, and water spray holes are arranged at intervals on the cleaning water pipe, and hot water connected to the cleaning water pipe can be sprayed onto the surface of the photovoltaic thermal panel 111 to wash away dust and other pollutants on the surface of the photovoltaic thermal panel 111. At the same time, since the cleaning water is hot water obtained by heat exchange, the cleaning efficiency of hot water will be much higher than that of other low-temperature water, thereby achieving efficient cleaning of the photovoltaic thermal panel 111.

[0070] Furthermore, the cleaning water valve 142 can be used to control the on / off of the water path connected to the water spraying device 141 by the three-way valve 150. When it is determined that the photovoltaic thermal panel 111 needs to be cleaned, the cleaning water valve 142 can be turned on to spray the hot water obtained by heat exchange onto the surface of the photovoltaic thermal panel 111. When it is not necessary to clean the photovoltaic thermal panel 111, the cleaning water valve 142 can be kept closed, and the hot water obtained by heat exchange does not need to be sprayed onto the surface of the photovoltaic thermal panel 111.

[0071] In an exemplary embodiment, Figure 4As shown, the solar collector module 110 also includes a gas-liquid separator 113, a compressor 114, an expander 115 and a liquid reservoir 116. The photovoltaic thermal panel 111, the gas-liquid separator 113, the compressor 114, the heat exchanger 112, the expander 115 and the liquid reservoir 116 are connected in sequence via pipelines to form a refrigerant circuit.

[0072] Specifically, the photovoltaic thermal panel 111 may be composed of a photovoltaic panel, a thermal conductive adhesive layer, a microchannel layer, a thermal insulation layer and a back panel. The microchannel layer runs through the interior of the photovoltaic thermal panel 111, one end of the microchannel layer may be connected to the gas-liquid separator 112, and the other end of the microchannel layer may be connected to the liquid reservoir 116, thereby forming a closed refrigerant circuit with the head-to-tail relationship of the photovoltaic thermal panel 111, the gas-liquid separator 113, the compressor 114, the heat exchanger 112, the expander 115 and the liquid reservoir 116.

[0073] It can be understood that a refrigerant, which is generally a low-boiling-point refrigerant, circulates inside the refrigerant circuit. Taking the heat exchanger 112 as a condenser as an example, in the process of converting solar energy into electrical energy by the photovoltaic thermal panel 111, the waste heat generated can be radiated by the thermal conductive adhesive layer on it to the refrigerant in the microchannel layer in the photovoltaic thermal panel. The refrigerant absorbs heat in the microchannel layer and evaporates into a gaseous state, and then flows to the compressor 113 after separation by the gas-liquid separator 112, flows to the condenser after being pressurized and heated by the compressor 113, and then condensed and released into a liquid state by the condenser, and after throttling and reducing the pressure by the expander 115, it is stored in the heat storage 116, so as to be circulated to the microchannel layer in the photovoltaic thermal panel 111 for heat absorption and evaporation.

[0074] The gas-liquid separator 113, the compressor 114, the expander 115 and the liquid storage device 116 are not limited to the devices that can be used, and can be selected according to the actual heat collection requirements. For example, the expander 115 can be implemented by an electronic expansion valve.

[0075] In an exemplary embodiment, Figure 5 As shown, the data acquisition module 130 is also used to collect hot water status data in the water tank 121; the cleaning module 140 is also used to connect the hot water to the photovoltaic thermal panel 111 when it is determined that cleaning is required based on the photovoltaic status data and the hot water status data.

[0076] Specifically, the hot water status data in the water tank 121 may include the amount of hot water in the water tank 121. It can be understood that when the amount of hot water in the water tank 121 is lower than the first preset water volume, it indicates that the amount of hot water in the water tank 121 is insufficient. At this time, it is not recommended to connect it to the photovoltaic thermal panel 111 to achieve self-cleaning of the photovoltaic thermal panel 111, which may affect the needs of heating and domestic hot water. Then, when the amount of hot water in the water tank 121 is higher than the second preset water volume, it is determined that cleaning is required and the hot water is connected to the photovoltaic thermal panel 111. Among them, the values ​​of the first preset water volume and the second preset water volume are not limited, and can be set according to actual technical requirements, and the two can use the same water volume threshold or different water volume thresholds, which can be selected by technicians as needed.

[0077] Furthermore, the hot water status data in the water tank 121 may also include the water temperature of the hot water in the water tank 121. It is understood that the higher the water temperature of the hot water, the better the cleaning effect on the photovoltaic thermal panel 111. Then, when the water temperature of the hot water in the water tank 121 is greater than the preset water temperature, it is determined that cleaning is required and the hot water is connected to the photovoltaic thermal panel 111.

[0078] It can be understood that the above judgment based on the hot water status data can be a separate judgment on whether cleaning is required, or it can be combined with the photovoltaic status data. When cleaning is determined to be required based on both the photovoltaic status data and the hot water status data, the hot water is connected to the photovoltaic thermal panel 111.

[0079] In an exemplary embodiment, referring to Figure 5 The data acquisition module 130 includes a pollutant sensor 131 and a temperature sensor 132 . The pollutant sensor 131 is disposed on the photovoltaic thermal panel 111 , and the temperature sensor 132 is disposed at the water outlet of the water tank 121 .

[0080] Specifically, this embodiment is explained by taking the photovoltaic state data as the pollution degree of the photovoltaic thermal panel 111 and the hot water state data as the hot water temperature in the water tank 121 as an example. Among them, the pollutant sensor 131 is used to collect the pollution degree of the photovoltaic thermal panel 111, and the temperature sensor 132 is used to collect the hot water temperature in the water tank 121.

[0081] Furthermore, when the pollution degree of the photovoltaic thermal panel 111 is greater than the preset pollution degree and the hot water temperature in the water tank 121 is greater than the preset water temperature, the cleaning module 140 is controlled to connect the hot water to the photovoltaic thermal panel 111 to achieve self-cleaning of the photovoltaic thermal panel 111.

[0082] Exemplarily, the photovoltaic thermal system may further include a controller, which may be integrated on a photovoltaic thermal panel or other device. The controller may obtain the photovoltaic status data and hot water status data acquired by the above data acquisition module to control the cleaning module, and connect the hot water in the water tank to the photovoltaic thermal panel when it is determined that cleaning is required.

[0083] It can be understood that the controller is the control center of the photovoltaic thermal system, which can be a control chip or control circuit board set in a device such as a photovoltaic thermal panel, or an external control system based on wireless communication. The external control system can be implemented through devices such as terminals or servers. The terminals can be, but are not limited to, various personal computers, laptops, smart phones, tablets, Internet of Things devices and portable wearable devices. Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart car devices, projection devices, etc. Portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. Head-mounted devices can be virtual reality (VR) devices, augmented reality (AR) devices, smart glasses, etc. The server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0084] In combination with the above embodiments, in an exemplary embodiment, Figure 6 As shown, a control method for a photovoltaic thermal system is provided, which can be applied to the photovoltaic thermal system described in any of the above embodiments, and can be specifically applied to the controller of the above photovoltaic thermal system. The method includes the following steps 202 to 204, wherein:

[0085] Step 202, obtaining photovoltaic status data of the photovoltaic thermal panel.

[0086] Specifically, the photovoltaic thermal panel is arranged in the heat collection module of the photovoltaic thermal system. The heat collection module adopts photovoltaic / thermal (PVT) technology, which is a new type of solar energy utilization method that integrates power generation and heat collection. On the basis of photovoltaic power generation, the waste heat generated by the photovoltaic panels is recovered at the same time to achieve solar energy cogeneration. It not only improves the utilization efficiency of solar energy, but also reduces the temperature of the photovoltaic thermal panel, thereby improving the power generation efficiency and extending the service life of the photovoltaic thermal panel. In the PVT technology, there is a photovoltaic part that converts solar energy into electrical energy, and a heat dissipation part that converts the waste heat generated during the operation of the photovoltaic thermal panel into thermal energy. The heat collection module mentioned in this application mainly corresponds to the above-mentioned heat dissipation part.

[0087] Among them, according to different cooling technologies, the heat collection module can adopt different specific structures to realize the heat collection function. For example, it can generally be divided into two types: liquid cooling and air cooling. Among them, the liquid cooling method usually uses water or refrigerant as the cooling medium, and transfers heat to the cooling medium through the heat transfer pipe to realize heat recovery. The air cooling method usually uses gas (such as air) as the cooling medium in the heat transfer pipe, and then adjusts the cooling effect by controlling the gas circulation speed in the heat transfer pipe.

[0088] Furthermore, the hydrothermal module can exchange heat with the heat collection module to use the heat collected by the heat collection module as a heat source for heating water to obtain hot water. The hydrothermal module may include a water flow pipeline, and the water flow pipeline may be arranged close to the heat collection module to achieve effective heat exchange. The hot water generated by the hydrothermal module can be used for heating and domestic hot water, for example, it can be suitable for rural heating, independent building heating and other scenarios.

[0089] It is understandable that due to the long-term exposure of photovoltaic thermal panels to the outdoor environment, dust and other pollutants will inevitably accumulate during operation, which will lead to a sharp drop in the efficiency of photoelectric conversion and photothermal conversion.

[0090] In order to effectively determine when to start cleaning the photovoltaic thermal panel, the photovoltaic status data of the photovoltaic thermal panel can be collected through the data acquisition module. Among them, the type of photovoltaic status data of the photovoltaic thermal panel is not unique. For example, the photovoltaic status data may include the degree of pollution of the photovoltaic thermal panel, the light intensity received by the photovoltaic thermal panel, the relevant parameter information of the photovoltaic thermal panel during power generation and heat collection, and the weight of the photovoltaic thermal panel. It can be understood that after pollutants accumulate on the surface of the photovoltaic thermal panel, the light intensity, power generation and heat collection efficiency, and weight that it can receive will change, which can be used to determine whether the photovoltaic thermal panel needs to be cleaned. Among them, the degree of pollution of the photovoltaic thermal panel can provide the most direct and accurate feedback on whether pollutants have accumulated on the surface of the photovoltaic thermal panel. Therefore, the embodiment of the present application uses the degree of pollution of the photovoltaic thermal panel as the photovoltaic status data.

[0091] Step 204 , when it is determined based on the photovoltaic status data that cleaning is required, the cleaning module is started to connect the hot water of the hydrothermal module to the photovoltaic thermal panel.

[0092] After the photovoltaic status data is detected, if it is determined that cleaning is required based on the photovoltaic status data, the cleaning module can be controlled to connect hot water to the photovoltaic thermal panel to achieve self-cleaning of the photovoltaic thermal panel. In the case where the pollution degree of the photovoltaic thermal panel is used as the photovoltaic status data, a preset pollution degree can be set as the judgment threshold, that is, when the pollution degree of the photovoltaic thermal panel is greater than the preset pollution degree, the cleaning module is controlled to connect hot water to the photovoltaic thermal panel to achieve self-cleaning of the photovoltaic thermal panel.

[0093] Among them, the cleaning module can be used to connect to the hydrothermal module and transmit the hot water generated by the hydrothermal module to the photovoltaic thermal panel to achieve self-cleaning of pollutants accumulated on the surface of the photovoltaic thermal panel. It can be understood that the cleaning module can be a device fixedly arranged at the upper end of the photovoltaic thermal panel to spray water to clean the photovoltaic thermal panel, or a cleaning device that can reciprocate on the surface of the photovoltaic thermal panel, or a spray device that can spray liquid with a cleaning agent. As long as it is a device that can achieve self-cleaning of the surface of the photovoltaic thermal panel, it can be used as the cleaning module in this embodiment.

[0094] In an exemplary embodiment, Figure 7 As shown, the control method of the photovoltaic thermal system further includes step 203, obtaining hot water status data in the water tank.

[0095] Continue to refer to Figure 7 , step 204 includes: when it is determined based on the photovoltaic status data and the hot water status data that cleaning is required, starting the cleaning module and connecting the hot water of the hydrothermal module to the photovoltaic thermal panel.

[0096] Specifically, the hot water status data in the water tank may include the amount of hot water in the water tank. It is understandable that when the amount of hot water in the water tank is lower than the preset amount, it indicates that the amount of hot water in the water tank is insufficient. At this time, it is not recommended to connect it to the photovoltaic thermal panel to achieve self-cleaning of the photovoltaic thermal panel, which may affect the needs of heating and domestic hot water. Then, when the amount of hot water in the water tank is higher than the preset amount, it is determined that cleaning is required and the hot water is connected to the photovoltaic thermal panel.

[0097] Furthermore, the hot water status data in the water tank may also include the hot water temperature in the water tank. It is understood that the higher the hot water temperature, the better the cleaning effect on the photovoltaic thermal panel. Then, when the hot water temperature in the water tank is greater than the preset water temperature, it is determined that cleaning is required and the hot water is connected to the photovoltaic thermal panel.

[0098] It can be understood that the above judgment based on the hot water status data can be a separate judgment on whether cleaning is required, or it can be combined with the photovoltaic status data. When cleaning is determined to be required based on both the photovoltaic status data and the hot water status data, the hot water is connected to the photovoltaic thermal panel.

[0099] In an exemplary embodiment, the photovoltaic status data includes a pollution level, and the hot water status data includes a hot water temperature.

[0100] Step 204 includes: when the pollution degree is greater than a preset pollution degree and the hot water temperature is greater than a preset water temperature, determining that cleaning is required.

[0101] Specifically, the data acquisition module includes a pollutant sensor and a temperature sensor. The pollutant sensor is arranged on the photovoltaic thermal panel, and the temperature sensor is arranged on the water outlet of the water tank.

[0102] This embodiment is explained by taking the photovoltaic state data as the pollution degree of the photovoltaic thermal panel and the hot water state data as the hot water temperature in the water tank as an example. Among them, the pollutant sensor is used to collect the pollution degree of the photovoltaic thermal panel, and the temperature sensor is used to collect the hot water temperature in the water tank.

[0103] Furthermore, when the pollution degree of the photovoltaic thermal panel is greater than the preset pollution degree and the hot water temperature in the water tank is greater than the preset water temperature, the cleaning module is controlled to connect the hot water to the photovoltaic thermal panel to achieve self-cleaning of the photovoltaic thermal panel.

[0104] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0105] In a specific embodiment, Figure 8 As shown, a photovoltaic thermal system is provided, including a micro water spray device 1, a valve 2, a pollution level sensor 3, a photovoltaic thermal component 4, a gas-liquid separator 5, a compressor 6, a condenser 7, a water pump 8, a water tank 9, a three-way valve 10, a liquid reservoir 11, an electronic expansion valve 12 and a water supply port 13.

[0106] Specifically, the photovoltaic thermal system of this embodiment consists of three parts.

[0107] The first part consists of a photovoltaic thermal component 4, a gas-liquid separator 5, a compressor 6, a condenser 7, a liquid storage tank 11 and an electronic expansion valve 12. Its main function is to heat the refrigerant in the microchannel layer of the photovoltaic thermal component through the heat collecting part in the photovoltaic thermal component 4, and then further heat it through the compressor 6 and transfer the heat to the condenser 7.

[0108] The second part consists of a condenser 7, a water pump 8, a water tank 9 and a three-way valve 10. Its main function is that the water pump 8 drives the water circulation, transfers the heat of the first part to the condenser 7, brings out the heat through heat exchange to form hot water, and then stores it in the water tank 9. The hot water generated in the water tank 9 can be used as domestic hot water or heating.

[0109] The third part is composed of a micro-spray device 1, a valve 2 and a pollution level sensor 3. Its main functions are as follows: Fig. 9 As shown, when the first part of the heat collection process is operating normally, the pollution level sensor 3 detects that the pollution level of the photovoltaic thermal panel is greater than the critical value and the water temperature in the water tank 9 is also greater than the critical value, the valve 2 is opened, so that the micro-spraying device 1 can operate normally and realize self-cleaning of the photovoltaic thermal panel.

[0110] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0111] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A photovoltaic thermal system, characterized in that: include: A heat collection module including a photovoltaic thermal panel is used to collect heat; A hydrothermal module, used for performing heat exchange with the heat collection module to obtain hot water; A data acquisition module, used to collect photovoltaic status data of the photovoltaic thermal panel; A cleaning module is used to connect the hot water to the photovoltaic thermal panel when it is determined based on the photovoltaic status data that cleaning is required.

2. The photovoltaic thermal system according to claim 1, characterized in that: The heat collection module further includes a heat exchanger, and a refrigerant circuit is connected between the photovoltaic thermal panel and the heat exchanger.

3. The photovoltaic thermal system according to claim 2, characterized in that: The hydrothermal module comprises a water tank and a hot water pump, the water tank is connected to a hot water circuit, and the hot water pump is arranged in the hot water circuit; The hot water circuit and the refrigerant circuit exchange heat in the heat exchanger.

4. The photovoltaic thermal system according to claim 3, characterized in that: It also includes a three-way valve, and the cleaning module includes a water spray device and a cleaning water valve; The water outlet of the water tank is connected to the hot water circuit through the first water outlet of the three-way valve, and is also connected to the water spray device through the second water outlet of the three-way valve. The clean water valve is arranged on the water path from the three-way valve to the water spray device.

5. The photovoltaic thermal system according to claim 3, characterized in that: The data acquisition module is also used to collect hot water status data in the water tank; The cleaning module is further used to connect the hot water to the photovoltaic thermal panel when it is determined that cleaning is required based on the photovoltaic status data and the hot water status data.

6. The photovoltaic thermal system according to claim 5, characterized in that: The data acquisition module includes a pollutant sensor and a temperature sensor. The pollutant sensor is arranged on the photovoltaic thermal panel, and the temperature sensor is arranged on the water outlet of the water tank.

7. The photovoltaic thermal system according to claim 2, characterized in that: The heat collection module also includes a gas-liquid separator, a compressor, an expander and a liquid reservoir. The photovoltaic thermal panel, the gas-liquid separator, the compressor, the heat exchanger, the expander and the liquid reservoir are connected in sequence through pipelines to form the refrigerant circuit.

8. A control method for a photovoltaic thermal system, applied to the photovoltaic thermal system according to any one of claims 1 to 7, characterized in that: The method comprises: Obtain photovoltaic status data of photovoltaic thermal panels; When it is determined based on the photovoltaic status data that cleaning is required, the cleaning module is started to connect the hot water of the hydrothermal module to the photovoltaic thermal panel.

9. The method according to claim 8, characterized in that The method further comprises: Get the hot water status data in the water tank; In the case where it is determined based on the photovoltaic state data that cleaning is required, starting the cleaning module to connect the hot water of the hydrothermal module to the photovoltaic thermal panel includes: When it is determined that cleaning is required based on the photovoltaic status data and the hot water status data, the cleaning module is started to connect the hot water of the hydrothermal module to the photovoltaic thermal panel.

10. The control method according to claim 9, characterized in that: The photovoltaic status data includes the pollution degree, and the hot water status data includes the hot water temperature; The determining that cleaning is required based on the photovoltaic status data and the hot water status data includes: When the pollution degree is greater than a preset pollution degree and the hot water temperature is greater than a preset water temperature, it is determined that cleaning is required.

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