Photovoltaic heat recovery and reuse system

Abstract

The application discloses a photovoltaic heat recycling system, which mainly comprises a photovoltaic array, a heat pump unit and a two-stage heat exchanger set. The photovoltaic array comprises a plurality of photovoltaic cell panels and is responsible for generating electric energy. The heat pump unit is driven by the electric energy generated by the photovoltaic array, can absorb heat from the environment, and can supply heat to user terminals with different temperature requirement levels. The two-stage heat exchanger set is provided with two heat exchangers with different temperature levels, can absorb waste heat generated by the photovoltaic cell panels for utilization, and can perform gradient recycling on waste heat generated by user terminals with different temperature requirement levels, so that the waste heat can be supplied to user terminals with lower temperature requirements. The system realizes efficient utilization of heat, fully recycles waste heat and waste heat while meeting the user requirements by obtaining environmental heat, improves the comprehensive energy utilization rate, and provides a new solution for efficient utilization of energy.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic heat recovery, and more particularly to a photovoltaic heat recovery and reuse system. Background Art

[0002] Against this backdrop, solar energy, as a clean and renewable energy source, has become a key focus in the energy sector. Photovoltaic technology, which converts solar energy into electricity through photovoltaic cells, has developed rapidly, with installed capacity steadily increasing. However, the energy conversion efficiency of photovoltaic cells is limited, typically only 15%-25%. Most of the solar energy is wasted as heat, causing the cell temperature to rise, which not only reduces power generation efficiency but also shortens its service life. To improve the comprehensive utilization of solar energy, photovoltaic heat recovery and reuse systems have been developed. Early systems mostly used air or liquid cooling to recover waste heat. While air cooling is simple and low-cost, due to air's low specific heat capacity and poor heat transfer ability, heat recovery is limited and its application range is narrow. Liquid cooling offers high heat transfer efficiency, but the system is complex, requiring equipment such as circulation pumps, consuming electricity, and posing the risk of liquid leakage, resulting in high maintenance costs.

[0003] Later, advanced systems introduced heat pump technology, using electricity from photovoltaic arrays to drive heat pumps, absorbing heat from the environment and heating it to supply different users. However, existing photovoltaic heat recovery and reuse systems still have key shortcomings.

[0004] In fields like industrial production and construction, there are a variety of temperature requirements, such as high-temperature industrial processes, medium-temperature building heating and hot water supply, and low-temperature ventilation pre-cooling. However, existing systems lack effective mechanisms for cascading waste heat recovery and utilization. In industrial production, high-temperature waste heat is often not properly recovered and directly discharged, resulting in both energy loss and environmental thermal pollution. For example, high-temperature waste heat generated by some chemical production processes is discharged into the environment without being fully utilized, wasting a significant amount of energy. In the construction sector, different heat-using processes have different temperature requirements. Existing systems are unable to effectively utilize waste heat in a cascaded manner to meet the needs of each process, resulting in low energy efficiency. For example, patent application CN115307204A discloses a solar-coupled system that combines waste heat recovery from bathroom wastewater and exhaust gas. This system is designed primarily for waste heat recovery from bathroom wastewater and exhaust gas, as well as for heating, power supply, and hot water supply. By coupling a waste heat recovery unit, a solar photovoltaic system, and an air-source heat pump unit, it achieves a certain degree of comprehensive energy utilization. However, the application scenarios and focuses of this system are different from those of the photovoltaic heat recovery and reuse system. It does not focus on solving the problem of cascade recovery and utilization of waste heat that is widely present in industrial production and construction.

[0005] Therefore, how to solve the lack of waste heat cascade recovery and utilization mechanism in the existing photovoltaic heat recovery and reuse system to improve the comprehensive utilization efficiency of solar energy has become the biggest technical problem that needs to be solved urgently.

[0006] Furthermore, there's room for improvement in photovoltaic array maximum power point tracking technology. Output power is affected by factors like light intensity and temperature, and the maximum power point is prone to drift. Existing tracking methods can't track quickly and accurately in certain situations, reducing power generation efficiency. For example, when light intensity fluctuates rapidly, traditional methods can lag behind, impacting power generation.

[0007] Existing heat exchangers fail to meet system requirements in terms of heat transfer efficiency, compactness, and reliability. Long-term operation can lead to scaling and corrosion, which reduces heat transfer efficiency and impacts system performance and lifespan. By addressing these technical challenges and addressing shortcomings in photovoltaic array maximum power point tracking technology and suboptimal heat exchanger performance, this approach will enhance the stability and reliability of the photovoltaic system, potentially enabling photovoltaic heat recovery and reuse systems to play an even more important role in the energy sector. Summary of the Invention

[0008] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0009] Another object of the present invention is to provide a photovoltaic heat recovery and reuse system, which realizes the effective recovery and cascade utilization of waste heat and residual heat by rationally configuring the photovoltaic array, heat pump unit and two-stage heat exchange unit.

[0010] In order to achieve these purposes and other advantages according to the present invention, a photovoltaic heat recovery and reuse system is provided, comprising:

[0011] a photovoltaic array, which includes a plurality of photovoltaic panels;

[0012] Heat pump units, driven by electricity generated by photovoltaic arrays, are used to absorb heat from the environment and supply it to users with different temperature requirements;

[0013] A two-stage heat exchange unit, comprising two heat exchangers of different temperature levels, is used to absorb and utilize waste heat generated by photovoltaic panels, as well as to recover waste heat generated by users with different temperature requirements in a cascaded manner and supply it to users with the next higher temperature requirements;

[0014] Among them, the heat pump unit absorbs heat from the environment and transmits it to the first-level temperature demand user end through the first-level heat exchanger. The first-level heat exchanger receives the waste heat generated by the photovoltaic panels and the residual heat of the first-level temperature demand user end, and transmits it to the next-level temperature demand user end through the next-level heat exchanger. The next-level heat exchanger receives the residual heat discharged by the first-level heat exchanger.

[0015] Preferably, multiple photovoltaic panels are arranged in a matrix, and a spiral heat conduction channel is provided on the back of each photovoltaic panel. A heat conduction medium flows through the heat conduction channel, and the heat conduction medium absorbs the waste heat generated by the photovoltaic panels and transfers the heat to the first-stage heat exchanger.

[0016] Preferably, the photovoltaic array is formed by connecting n solar panels in series, and then connecting m groups of solar panels in series in parallel;

[0017] The output of the PV array is connected to a DC combiner box, which aggregates the DC outputs of m groups of series-connected solar panels. The DC power output by the DC combiner box is then connected to an inverter with maximum power point tracking (MPPT).

[0018] The maximum power point tracking function is implemented as follows:

[0019] S1. Divide the operating voltage range into multiple intervals, including a low voltage zone, a medium voltage zone, and a high voltage zone, based on the theoretical upper limit open circuit voltage of the output voltage of the photovoltaic array;

[0020] S2. Set different perturbation step sizes in each interval, where the perturbation step size in the low voltage area is larger than that in the medium voltage area, and the perturbation step size in the medium voltage area is larger than that in the high voltage area;

[0021] S3, real-time monitoring of the output voltage and current of the photovoltaic array, and calculation of the current power;

[0022] S4. Determine the interval to which the current voltage belongs based on the current voltage value and select the corresponding disturbance step size;

[0023] S5. Apply voltage disturbance, adjust the operating point of the photovoltaic array, and compare the power changes before and after the disturbance; if the power increases, maintain the disturbance direction; if the power decreases, reverse the disturbance direction;

[0024] S6. Repeat the above steps until the photovoltaic array operates at the maximum power point.

[0025] Preferably, the operating voltage range is divided into multiple intervals as follows based on the theoretical upper limit of the output voltage of the photovoltaic array, the open circuit voltage:

[0026] Low voltage area: 0~50% of open circuit voltage;

[0027] Medium voltage region: 50%~80% of the open circuit voltage; and,

[0028] High voltage area: 80%~100% of the open circuit voltage.

[0029] Preferably, setting different perturbation step sizes in each interval includes:

[0030] The step size in the low voltage region is 2.0V;

[0031] The step size in the medium voltage region is 1.0V;

[0032] The step size in the high voltage region is 0.5V.

[0033] Preferably, the steps of applying voltage disturbance, adjusting the operating point of the photovoltaic array, and comparing power changes before and after the disturbance in step S5 include:

[0034] S51, increasing or decreasing a disturbance step size based on the current voltage to obtain a new voltage value;

[0035] S52, adjusting the operating point of the photovoltaic array to a new voltage value;

[0036] S53. Measure the new power value and compare it with the power value before the disturbance.

[0037] Preferably, the flow channel is bonded to the back of the photovoltaic panel through thermal conductive silicone, with a bonding thickness of 0.5 mm and a coverage rate of ≥95%. A flow channel outlet joint is provided at the end of each thermal conductive flow channel, which is connected to the stainless steel corrugated hose by a thread; each stainless steel corrugated hose is collected into a stainless steel header through a multi-way header interface, and the header is connected to the inlet of the first-stage heat exchanger through a flange.

[0038] Preferably, the first-stage heat exchanger and the second-stage heat exchanger are both shell and tube heat exchangers, each comprising a shell, two independent tube passes, and a shell pass;

[0039] The outlet of the heat transfer channel is connected to the inlet of the first set of tubes of the first-stage heat exchanger. After the heat transfer medium has completed the heat exchange, it flows out of the outlet of the first set of tubes and enters the first set of independent tubes of the next-stage heat exchanger. After passing through the Y-shaped diverter pipe, it is finally distributed to the inlet of the heat transfer channel of each photovoltaic panel to achieve circulation.

[0040] The condenser outlet of the heat pump is connected to the second tube side inlet of the first stage heat exchanger. The refrigerant that has completed the heat exchange flows out from the second tube side outlet of the first stage heat exchanger, passes through the electronic expansion valve, and returns to the evaporator inlet of the heat pump to complete the cycle.

[0041] Connect the shell-side outlet of the first-stage heat exchanger to the liquid inlet of the first-stage temperature demand user end. The liquid outlet of the first-stage temperature demand user end is first connected to the second set of tube-side inlet of the next-stage heat exchanger, and then connected to the shell-side liquid inlet of the next-stage heat exchanger through the second set of tube-side outlet of the next-stage heat exchanger.

[0042] The outlet end of the shell side of the next-stage heat exchanger is connected to the liquid inlet of the second-stage temperature demand user end, and the outlet of the second-stage temperature demand user end is connected to the inlet end of the shell side of the first-stage heat exchanger to realize circulation.

[0043] Preferably, the photovoltaic heat recovery and reuse system also includes a heat storage mechanism for storing excess heat from the multi-stage heat exchange unit to provide heat when heat demand peaks or when the heat pump unit is insufficient.

[0044] The present invention has at least the following beneficial effects:

[0045] First, the photovoltaic heat recovery and reuse system of the present invention is equipped with a two-stage heat exchange unit. Through two heat exchangers of different temperature levels, it can effectively absorb and cascade the waste heat generated by photovoltaic panels and the residual heat generated by users with different temperature demand levels. The first-stage heat exchanger first receives the waste heat from the photovoltaic panels and the residual heat from the users with the first temperature demand, and then transmits it to the users with the next temperature demand through the second-stage heat exchanger, realizing the hierarchical utilization of the residual heat. This method can fully utilize the thermal energy of different temperature levels to meet the needs of different users. Compared with the existing system that lacks an effective cascade waste heat recovery mechanism, it greatly improves the comprehensive utilization efficiency of energy and reduces energy waste.

[0046] Secondly, the photovoltaic array described in the present invention is composed of individual panels connected in series, groups of series panels connected in parallel, and connected via a DC combiner box and an inverter with maximum power point tracking (MPPT) function. The MPPT function is implemented by dividing the operating voltage range into low, medium, and high voltage zones based on the theoretical upper limit of the photovoltaic array output voltage, the open-circuit voltage, and setting different perturbation step sizes in different zones (the low voltage zone step size is 2.0V, the medium voltage zone step size is 1.0V, and the high voltage zone step size is 0.5V). This optimized MPPT method can more quickly and accurately track the maximum power point of the photovoltaic array, monitor the output voltage and current in real time, and adjust the operating point. Compared with traditional maximum power point tracking methods, it can effectively avoid tracking lag when factors such as light intensity change, significantly improve the power generation efficiency of the photovoltaic array, and increase the power output of the system.

[0047] Third, the photovoltaic heat recovery and reuse system provided by the present invention is equipped with a thermal energy storage mechanism that can store excess heat recovered by the multi-stage heat exchange unit. When there is a peak in heat demand or insufficient heat supply from the heat pump unit, the thermal energy storage mechanism can provide heat in a timely manner, ensuring that the system can stably supply heat to the user end. This configuration enhances the stability and reliability of the system, effectively solves the unstable heat supply problem that may occur in existing systems, guarantees the heat demand of the user end, and improves the adaptability and practicality of the system.

[0048] Fourthly, the first-stage heat exchanger and the second-stage heat exchanger in the present invention both adopt shell-and-tube heat exchangers, and their internal structures and connection methods have been carefully designed; a reasonable circulation connection is formed between the heat-conducting channel and the heat exchanger, the heat pump unit, and the user end. For example, the outlet of the heat-conducting channel is connected to the inlet of the first set of tubes of the first-stage heat exchanger, and after completing the heat exchange, it enters the second-stage heat exchanger in turn, etc., thus realizing the circulation of the heat-conducting medium; the condenser outlet of the heat pump is connected to the inlet of the second tube of the first-stage heat exchanger, and the refrigerant is also circulated; this design not only improves the heat exchange efficiency, but also ensures that the components are tightly connected and the circulation is orderly. Compared with the existing heat exchangers that are prone to scaling, corrosion, etc., which lead to a decrease in heat transfer efficiency, the heat exchanger structure and circulation design of the present invention are more reliable, which can effectively ensure the long-term stable operation of the system, extend the service life of the system, and reduce maintenance costs;

[0049] Fifth, the spiral heat-conducting channel set on the back of each photovoltaic panel of the present invention is bonded to the back of the panel through thermal conductive silicone with a bonding thickness of 0.5mm and a coverage rate of not less than 95%, and a channel outlet joint is set at the end of each heat-conducting channel, which is threadedly connected to the stainless steel corrugated hose. The hoses are collected into the stainless steel header through a multi-way header interface, and then connected to the inlet of the first-stage heat exchanger through a flange; this precise structural design and connection method ensures that the heat-conducting medium can efficiently and stably absorb the waste heat generated by the photovoltaic panel and accurately transfer the heat to the first-stage heat exchanger, reducing the loss during heat transmission, improving the efficiency and stability of waste heat recovery, and further enhancing the entire system's ability to recycle waste heat from photovoltaic panels.

[0050] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic structural diagram of a photovoltaic heat recovery and reuse system in one technical solution of the present invention;

[0052] Figure 2 This is a structural diagram of another technical solution of the present invention to the photovoltaic heat recovery and reuse system;

[0053] Among them, 1. Photovoltaic panels; 2. First-stage heat exchanger; 3. First-stage temperature demand user end; 4. Heat pump unit; 5. Second-stage heat exchanger; 6. Second-stage temperature demand user end; 7. Thermal energy storage mechanism. DETAILED DESCRIPTION

[0054] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0055] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0056] As shown in Figure 1 , 2 The present application provides a photovoltaic heat recycling system, comprising:

[0057] a photovoltaic array comprising a plurality of photovoltaic panels 1;

[0058] a heat pump unit 4 driven by the electric energy generated by the photovoltaic array for absorbing heat from the environment and supplying for use by user terminals with different temperature requirement levels;

[0059] a two-stage heat exchanger unit comprising two heat exchangers with different temperature levels for absorbing and utilizing the waste heat generated by the photovoltaic panels 1 and recycling and supplying the waste heat generated by the user terminals with different temperature requirement levels to the user terminals with lower temperature requirement levels;

[0060] wherein the heat pump unit 4 absorbs heat from the environment and delivers it to the user terminals with the first temperature requirement level 3 through the first-stage heat exchanger 2, the first-stage heat exchanger 2 receives the waste heat generated by the photovoltaic panels 1 and the waste heat of the user terminals with the first temperature requirement level 3, and delivers it to the user terminals with the second temperature requirement level 6 through the second-stage heat exchanger 5, the second-stage heat exchanger 5 receives the waste heat discharged by the first-stage heat exchanger 2.

[0061] In the above technical solution, the photovoltaic array, serving as the energy source for the entire system, is composed of several photovoltaic panels 1. These panels utilize the photoelectric effect to convert solar energy into electricity. This advantage lies in its renewable, clean, and environmentally friendly nature, reducing reliance on traditional fossil fuels and lowering carbon emissions. Multiple photovoltaic panels 1 form an array, and in practical applications, their scale can be flexibly adjusted to meet the system's power requirements in various scenarios. Whether it's a small residential building or a large commercial building or industrial plant, the number and layout of photovoltaic panels 1 can ensure stable power supply. The heat pump unit 4, powered by the electricity generated by the photovoltaic array, is a key component in the system's heat conversion and transport. Its operating principle is to absorb heat from the environment (air, water, or soil) by consuming a small amount of electricity and raising it to a higher temperature, thereby providing heat to users with varying temperature requirements. This method offers higher energy efficiency than traditional methods of directly burning energy to obtain heat. Taking the air source heat pump as an example, it can absorb heat from low-temperature air, and after being compressed and heated by the compressor, it transfers the heat to the user end for heating. The heat pump unit 4 can adjust the temperature of the output heat according to the needs of the user end with different temperature requirements, meet the different temperature requirements of domestic hot water supply, space heating, and industrial production processes, and improve the targetedness and flexibility of energy utilization.

[0062] In the above technical solution, the two-stage heat exchanger system includes heat exchangers of different temperature levels, which play a key role in waste heat recovery and cascaded utilization. The heat exchanger design achieves efficient heat transfer, and the different temperature levels meet the heat quality requirements of different users. The first-stage heat exchanger 2 receives heat absorbed and transferred from the environment by the heat pump unit 4 and transfers it to the first-stage temperature-demanding user 3. It also collects waste heat generated by the photovoltaic panels 1. The first-stage heat exchanger 2 also receives waste heat discharged from the first-stage temperature-demanding user 3. This heat is further transferred to the second-stage heat exchanger 5 for preliminary heat recovery and redistribution. This design not only improves the utilization rate of waste heat from the photovoltaic panels 1, but also fully utilizes the waste heat discharged by the user, reducing energy waste. The second-stage heat exchanger 5 receives the waste heat discharged by the first-stage heat exchanger 2 and transfers it to the next-stage temperature-demanding user 6. This cascaded waste heat recovery and utilization method greatly improves the overall energy utilization rate. In some industrial production processes, certain links have higher temperature requirements, while others have relatively lower temperature requirements. Using a two-stage heat exchanger, waste heat from high-temperature users can be processed in the next-stage heat exchanger 5 and then supplied to users with lower temperature requirements, achieving reasonable distribution and efficient utilization of heat between different users.

[0063] In the above technical solution, the user terminals that do not require temperature vary according to the user's demand for heat and the purpose. The following lists several segmentation methods for user terminals with first-level temperature requirements and user terminals with second-level temperature requirements. First, based on the temperature range, the user terminals with first-level temperature requirements are users with temperature requirements greater than 100°C. Such user terminals usually require higher temperature heat energy to meet specific process or production requirements. For example, in the chemical industry, some chemical reactions need to be carried out in a high-temperature environment; the user terminals with second-level temperature requirements are users with temperature requirements less than or equal to 100°C. Such user terminals usually have certain temperature requirements but do not need too high temperatures, such as the heating system of buildings and the use of domestic hot water. Second, based on the industry and application scenario, the user terminals with first-level temperature requirements are high-temperature industrial production user terminals, such as the chemical and metallurgical industries, and the user terminals with second-level temperature requirements are non-high-temperature industrial production user terminals, such as food processing, papermaking, building heating, greenhouse temperature regulation, irrigation water preheating, etc.

[0064] An application example of the above technical solution is as follows:

[0065] A photovoltaic heat recovery and reuse system has been installed in a residential complex. The photovoltaic array, consisting of 500 high-efficiency monocrystalline silicon photovoltaic panels 1, is installed on the roofs of the community's public buildings, with a total installed capacity of 100 kWp. The heat pump unit 4 uses a 50 kW air-source heat pump, capable of stable operation in ambient temperatures ranging from -15°C to 40°C. The two-stage heat exchanger consists of a plate-type first-stage heat exchanger 2 and a shell-and-tube second-stage heat exchanger 5. During daytime, when sunlight is abundant, the photovoltaic array generates electricity to drive the heat pump unit 4. The heat pump absorbs heat from the surrounding air and heats hot water to 60°C in the first-stage heat exchanger 2. This heat is then supplied to users within the community who require hot water at higher temperatures, such as public bathrooms and some residents with higher water temperature requirements, to meet their daily bathing and domestic hot water needs. During this process, the first-stage heat exchanger 2 also collects waste heat generated by the photovoltaic panels 1, which further raises the hot water temperature, reducing the heat pump's energy consumption. At the same time, the hot water used by the first-stage temperature demand user 3 drops to approximately 45°C. The remaining heat is recovered by the first-stage heat exchanger 2 and then transferred via the next-stage heat exchanger 5 to users requiring lower-temperature hot water, such as the residential heating system, where it is heated to 35°C-40°C for indoor heating in winter. The next-stage heat exchanger 5 receives the waste heat discharged by the first-stage heat exchanger 2, further raising the temperature of the heating water and achieving a cascaded utilization of waste heat. Through the operation of this system, the residential community's domestic hot water and heating needs are effectively met, reducing reliance on traditional gas water heaters and boilers and lowering energy costs. According to statistics, compared with traditional energy supply methods, the community can save approximately 30,000 cubic meters of natural gas consumption annually, reduce carbon dioxide emissions by approximately 75 tons, and reduce energy costs by approximately 40%.

[0066] In the above technical solution, the photovoltaic heat recovery and reuse system forms a set of efficient energy comprehensive utilization system by integrating the photovoltaic array, the heat pump unit 4 and the two-stage heat exchange unit, which has at least the following beneficial effects:

[0067] 1. The photovoltaic heat recovery and reuse system fully utilizes the electrical energy generated by the photovoltaic panels 1 to drive the heat pump unit 4, thereby absorbing heat from the environment to provide heating for the user end. At the same time, the two-stage heat exchange unit recovers and cascades the waste heat of the photovoltaic panels 1 and the residual heat generated by the user ends with different temperature requirements, allowing heat to be transferred between the user ends with different temperature requirements, reducing energy waste and greatly improving the comprehensive energy utilization rate. The waste heat and residual heat that would have been wasted are reused a second time or even multiple times, improving the energy output-input ratio of the entire system and reducing energy costs.

[0068] 2. The heat pump unit 4 can supply heat to users with different temperature demand levels, and the two-stage heat exchange unit further realizes the cascade distribution of heat, meeting the diverse energy needs in different scenarios such as domestic hot water, heating, and industrial production, thereby improving the applicability and practicality of the system. Whether it is an industrial production process with high temperature requirements or indoor heating and domestic hot water supply with relatively low temperature requirements, the system can accurately provide heat energy at the appropriate temperature.

[0069] 3. The photovoltaic heat recovery and reuse system combines solar energy and ambient heat energy. Multiple energy sources make the energy supply more stable and reliable. When solar energy resources are sufficient, the electricity generated by the photovoltaic array provides power for the heat pump unit 4. When solar energy is insufficient, the heat pump unit 4 can still absorb heat from the environment to maintain operation, ensuring a continuous and stable energy supply under different weather and seasonal conditions.

[0070] 4. Using solar energy as part of the energy input reduces dependence on traditional fossil energy and reduces pollutant emissions caused by burning fossil energy. It is in line with the concept of sustainable development and plays a positive role in environmental protection. In addition, efficient energy utilization reduces the total energy consumption and indirectly reduces the negative impact of the energy production process on the environment. By recycling and reusing waste heat and residual heat, additional energy consumption is reduced and the operating cost of the system is reduced. For enterprises and users, long-term use of this system can save a lot of energy costs and improve economic benefits.

[0071] In another specific embodiment of the present invention, a plurality of photovoltaic panels are arranged in a matrix, and a spiral heat conduction channel is provided on the back of each photovoltaic panel 1. A heat conduction medium flows through the heat conduction channel. The heat conduction medium absorbs the waste heat generated by the photovoltaic panel 1 and transfers the heat to the first-stage heat exchanger 2.

[0072] In the above technical solution, multiple photovoltaic panels 1 are arranged in a matrix. The matrix arrangement can make full use of the installation space and improve the power generation efficiency per unit area of ​​the photovoltaic array. In a limited space, by rationally planning the number of rows and columns of the matrix, the number of photovoltaic panels 1 installed can be maximized, thereby improving the power generation capacity of the entire photovoltaic array. A spiral heat conduction channel is provided on the back of each photovoltaic panel 1, and a heat conduction medium flows through the heat conduction channel. The spiral design increases the flow path of the heat conduction medium on the back of the photovoltaic panel 1 and prolongs the contact time between the heat conduction medium and the photovoltaic panel 1. When the photovoltaic panel 1 generates electricity under light conditions, a large amount of waste heat will inevitably be generated. This waste heat will affect the power generation efficiency and service life of the photovoltaic panel 1. When the heat conduction medium flows in the spiral channel, it can fully absorb this waste heat, and then transfer the absorbed heat to the first-stage heat exchanger 2 to achieve waste heat recovery.

[0073] In the above technical solution, the spiral heat conduction channel significantly increases the contact area and contact time between the heat transfer medium and the photovoltaic panel 1. Compared to simple straight channels, the spiral channel allows the heat transfer medium to more fully absorb the waste heat generated by the photovoltaic panel 1, improving waste heat collection efficiency. By extending the flow path of the heat transfer medium, the waste heat is more thoroughly absorbed, reducing waste heat accumulation on the photovoltaic panel 1, and helping to maintain the photovoltaic panel 1 in good working condition. The waste heat generated by the photovoltaic panel 1 is transferred to the first-stage heat exchanger 2, providing more energy for subsequent heat utilization. This waste heat can be combined with other heat sources (such as heat absorbed from the environment by the heat pump unit 4) in the first-stage heat exchanger 2 to provide heat to the first-stage temperature demand user 3. Alternatively, through the coordinated operation of the two-stage heat exchange unit, the heat can be further transferred to the second-stage temperature demand user 6, thereby improving the energy utilization of the entire system and reducing energy waste. The timely removal of waste heat generated by the photovoltaic panel 1 helps to lower the operating temperature of the photovoltaic panel 1. Excessively high temperatures can reduce the power generation efficiency of photovoltaic panels 1, and prolonged exposure to high temperatures can shorten the service life of photovoltaic panels 1. The thermal conduction channels and heat transfer medium effectively reduce the temperature of photovoltaic panels 1, allowing them to operate within a more stable temperature range. This improves the stability of power generation efficiency, extends the service life of photovoltaic panels 1, and reduces the cost and maintenance workload of panel replacement.

[0074] In another specific embodiment of the present invention, the photovoltaic array is formed by connecting n solar panels in series, and then connecting m groups of solar panels in series in parallel;

[0075] The output of the PV array is connected to a DC combiner box, which aggregates the DC outputs of m groups of series-connected solar panels. The DC power output by the DC combiner box is then connected to an inverter with maximum power point tracking (MPPT).

[0076] The maximum power point tracking function is implemented as follows:

[0077] S1. Divide the operating voltage range into multiple intervals, including a low voltage zone, a medium voltage zone, and a high voltage zone, based on the theoretical upper limit open circuit voltage of the output voltage of the photovoltaic array;

[0078] S2. Set different perturbation step sizes in each interval, where the perturbation step size in the low voltage area is larger than that in the medium voltage area, and the perturbation step size in the medium voltage area is larger than that in the high voltage area;

[0079] S3, real-time monitoring of the output voltage and current of the photovoltaic array, and calculation of the current power;

[0080] S4. Determine the interval to which the current voltage belongs based on the current voltage value and select the corresponding disturbance step size;

[0081] S5. Apply voltage disturbance, adjust the operating point of the photovoltaic array, and compare the power changes before and after the disturbance; if the power increases, maintain the disturbance direction; if the power decreases, reverse the disturbance direction;

[0082] S6. Repeat the above steps until the photovoltaic array operates at the maximum power point.

[0083] In the above technical solution, the photovoltaic array consists of n panels connected in series, followed by m groups of these series panels connected in parallel. The purpose of series connection is to increase voltage, as in a series circuit, the total voltage is equal to the sum of the voltages of the individual panels. Parallel connection, on the other hand, increases current, as the total current in a parallel circuit is equal to the sum of the currents in each branch. This combination of series and parallel connections allows for flexible adjustment of the photovoltaic array's output voltage and current to meet the requirements of subsequent equipment. The output of the photovoltaic array is connected to a DC combiner box, which aggregates the DC output of the n series-connected panels. Since photovoltaic arrays typically consist of multiple panels connected in series and parallel, they have multiple DC outputs. The DC combiner box aggregates these outputs for subsequent unified processing and transmission, reducing wiring complexity. The DC power output from the DC combiner box is then fed into an inverter equipped with maximum power point tracking (MPPT). The inverter's primary function is to convert DC power into AC power to meet the needs of most electrical devices and the power grid. The MPPT function ensures that the photovoltaic array consistently operates near its maximum power point, improving the system's power generation efficiency.

[0084] In the above technical solution, the present invention further provides a method for implementing the maximum power point tracking function:

[0085] S1: Working voltage range division

[0086] Based on the open-circuit voltage, the theoretical upper limit of the PV array's output voltage, the operating voltage range is divided into multiple zones: low, medium, and high. Open-circuit voltage refers to the output voltage of the PV array under no-load conditions and serves as an important reference for the PV array's output voltage. By dividing the voltage ranges into different zones, different control strategies can be adopted for different voltage ranges.

[0087] S2: Set different perturbation step sizes

[0088] Different perturbation steps are set in each interval, the perturbation step of the low-voltage region is greater than that of the medium-voltage region, and the perturbation step of the medium-voltage region is greater than that of the high-voltage region. The perturbation step determines the amplitude of adjusting the operating point of the photovoltaic array each time. In the low-voltage region, because the distance from the maximum power point may be far, a larger perturbation step can make the system approach the maximum power point faster; while in the high-voltage region, because it has approached the maximum power point, a smaller perturbation step can avoid excessive adjustment, so that the system works more stably near the maximum power point.

[0089] S3: Real-time monitoring and power calculation

[0090] The output voltage and current of the photovoltaic array are monitored in real time, and the current power is calculated through the power calculation formula P=UI (where P is power, U is voltage, and I is current). This step is the basis for realizing the MPPT function. Only by accurately obtaining the current power in real time can the operating point be adjusted according to the power change.

[0091] S4: Determine the interval and select the perturbation step

[0092] According to the current voltage value, the corresponding perturbation step is selected. By judging which interval the current voltage is in, the system can automatically select the appropriate perturbation step for operating point adjustment, realizing adaptive control.

[0093] S5: Apply perturbation and compare power

[0094] Apply voltage perturbation to adjust the operating point of the photovoltaic array, and compare the power change before and after the perturbation. If the power increases, it means that the current perturbation direction is correct, and the adjustment continues in this direction; if the power decreases, it means that the perturbation direction is wrong, and the perturbation direction is reversed. This adjustment method based on power feedback can ensure that the system continuously approaches the maximum power point.

[0095] S6: Repeat the adjustment to the maximum power point

[0096] Repeat the above steps to continuously adjust the operating point of the photovoltaic array until the photovoltaic array works at the maximum power point. Because the light intensity, temperature and other environmental factors will change continuously, the maximum power point will also move, so continuous adjustment is needed to ensure that the photovoltaic array always works near the maximum power point.

[0097] The benefits of the above implementation method include at least the following: The MPPT function enables the PV array to consistently operate near its maximum power point, fully utilizing solar resources and improving the PV system's power generation efficiency. In particular, when environmental conditions such as light intensity and temperature change, the system can quickly adapt, reducing power losses caused by these changes and enabling the PV system to output the maximum amount of power under various operating conditions. Adaptive control is achieved by setting different perturbation step sizes for different voltage ranges. When the system is far from the maximum power point, a larger perturbation step size allows for faster approach to the maximum power point, shortening adjustment time. When the system is close to the maximum power point, a smaller perturbation step size prevents oscillation near the maximum power point, ensuring more stable operation at the maximum power point. This adaptive adjustment capability improves the system's response speed and stability. The PV array is connected in series and parallel, then combined via a DC combiner box and finally connected to an inverter with MPPT functionality. This system structure is clear and rational. The combination of series and parallel connections allows for flexible adjustment of output voltage and current. The DC combiner box reduces wiring complexity, and the MPPT inverter ensures efficient system operation. These components work together to enhance the reliability and performance of the entire PV system. Improved power generation efficiency means more energy can be generated under the same lighting conditions, effectively reducing the unit cost of electricity. Furthermore, the system's adaptive adjustment capabilities and stability reduce maintenance costs and economic losses caused by power loss, ultimately lowering the overall operating cost of the PV system.

[0098] In another specific embodiment of the present invention, the operating voltage range is divided into multiple intervals according to the theoretical upper limit of the output voltage of the photovoltaic array, the open circuit voltage, as follows:

[0099] Low voltage area: 0~50% of open circuit voltage;

[0100] Medium voltage region: 50%~80% of the open circuit voltage; and,

[0101] High voltage area: 80%~100% of the open circuit voltage.

[0102] In the above technical solution, open-circuit voltage refers to the output voltage of the photovoltaic array under no-load conditions. It represents the maximum voltage value that the photovoltaic array can output under the current light and temperature conditions and is an important parameter of the photovoltaic array output characteristics. Dividing the operating voltage range based on the open-circuit voltage can intuitively reflect the position of the photovoltaic array's current operating point relative to its maximum output capacity, thus providing a clear reference for subsequent control strategies. The specific ranges of each voltage range are as follows:

[0103] Low voltage range (0-50% open-circuit voltage): When the PV array's output voltage is within this range, it indicates that its operating point is far from its maximum power point. This may be due to factors such as low light intensity, high temperature, or excessive load. Within this range, the PV array's output power is relatively low, leaving ample room for improvement.

[0104] Medium voltage region (50% to 80% of open-circuit voltage): Within this range, the PV array's operating point gradually approaches its maximum power point. As the voltage rises, the output power also increases, but it still hasn't reached its maximum. At this stage, more refined operating point adjustments are necessary to further increase output power.

[0105] High voltage region (80% to 100% open-circuit voltage): When the output voltage is in this range, the PV array is very close to its maximum power point. At this point, output power changes are very sensitive to operating point adjustments, and smaller adjustments are required to avoid exceeding the maximum power point and causing output power to drop.

[0106] When implementing the MPPT function, the voltage range to which the current PV array output voltage belongs is determined based on the output voltage, and then the corresponding control strategy is selected. For example, in the low-voltage range, a larger perturbation step size is used to quickly approach the maximum power point; in the medium-voltage range, the perturbation step size is appropriately reduced for more precise adjustment; and in the high-voltage range, a smaller perturbation step size is used to ensure stable operation of the system near the maximum power point.

[0107] The setting of each voltage interval facilitates fast approximation of the maximum power point and precise adjustment of MPPT. The setting of a larger voltage range (0-50% open-circuit voltage) in the low-voltage zone and the adoption of a larger perturbation step enable the photovoltaic array to quickly approach the maximum power point when it is far away from the maximum power point. This can reduce the adjustment time of the system in the region far away from the maximum power point, improve the overall response speed, and faster reach a higher output power. The division of the medium-voltage zone (50%-80% open-circuit voltage) and the high-voltage zone (80%-100% open-circuit voltage) enables different smaller perturbation steps to be adopted according to different degrees of approximation when approaching the maximum power point. In the medium-voltage zone, the step is appropriately reduced for preliminary precise adjustment, and in the high-voltage zone, the step is further reduced for fine adjustment, which avoids overshooting the maximum power point due to an excessively large adjustment amplitude and improves the precision of MPPT. At the same time, the stability of the system can be enhanced, and excessive oscillation of the system near the maximum power point can be avoided. In the high-voltage zone, a very small perturbation step is adopted, so that the system can stably operate near the maximum power point, reduces power fluctuations caused by environmental factors or control errors, and improves the stability of the system output power. Finally, through efficient and precise MPPT control, the photovoltaic array can work near the maximum power point under different light and temperature conditions as much as possible, fully tapping the power generation potential of the photovoltaic array, improving the conversion efficiency of solar energy, and thus increasing the power generation of the entire photovoltaic system and optimizing the energy utilization efficiency. Improving energy utilization efficiency means that more electrical energy output can be obtained under the same investment and light resources, which is equivalent to reducing the production cost of unit electrical energy. Stable power output also reduces equipment wear and maintenance costs caused by power fluctuations, and reduces the overall operation cost of the photovoltaic system.

[0108] In another specific embodiment of the present application, setting different perturbation steps in each interval includes:

[0109] The step in the low-voltage zone is 2.0V;

[0110] The step in the medium-voltage zone is 1.0V;

[0111] The step in the high-voltage zone is 0.5V.

[0112] In the above-mentioned technical solution, during the maximum power point tracking (MPPT) process of the photovoltaic heat recovery and reuse system, specific perturbation step sizes are set based on the different operating voltage ranges of the photovoltaic array. This is a key step in achieving efficient and accurate tracking of the maximum power point. Using a larger perturbation step size in the low-voltage range enables the photovoltaic array to quickly adjust its operating point when it is far from the maximum power point, significantly shortening the time required to approach the maximum power point. As the operating point approaches the maximum power point, the perturbation step size is gradually reduced, enabling precise operating point adjustment at different stages. In the medium and high voltage ranges, a smaller step size allows for more detailed capture of power variations, preventing the maximum power point from being missed due to excessive adjustments. This ensures that the system tracks the maximum power point as accurately as possible and operates stably near it, thereby improving overall power generation efficiency. Properly setting perturbation step sizes in different ranges avoids power fluctuations caused by excessive step sizes when approaching the maximum power point. Using a very small step size in the high voltage range ensures smoother system adjustments near the maximum power point, reducing power fluctuations and providing a stable energy input for subsequent heat recovery and utilization, thus facilitating the stable operation of the entire photovoltaic heat recovery and reuse system. Compared to using a fixed, small step size, this rapid approximation strategy allows the system to begin operating at a higher power level more quickly, particularly during sudden changes in light intensity or during system startup, rapidly improving power generation efficiency. Changes in environmental factors such as light intensity and temperature can cause the maximum power point of the photovoltaic array to shift. This interval-based strategy of setting different perturbation step sizes adaptively adjusts to the current operating voltage range, allowing it to quickly and accurately track the new maximum power point under varying environmental conditions, improving the system's adaptability to environmental changes.

[0113] In another specific embodiment of the present invention, the steps of applying a voltage disturbance, adjusting the operating point of the photovoltaic array, and comparing power changes before and after the disturbance in step S5 include:

[0114] S51, increasing or decreasing a disturbance step size based on the current voltage to obtain a new voltage value;

[0115] S52, adjusting the operating point of the photovoltaic array to a new voltage value;

[0116] S53. Measure the new power value and compare it with the power value before the disturbance.

[0117] In the above technical solution, the steps of applying voltage disturbance, adjusting the operating point of the photovoltaic array, and comparing the power changes before and after the disturbance are specifically as follows:

[0118] S51: Get new voltage value

[0119] Based on the current operating voltage of the photovoltaic array, the voltage is increased or decreased according to the pre-set disturbance step size of the corresponding voltage range to obtain a new voltage value. For example, if the current operating voltage is in the low voltage range and the disturbance step size is 2.0V, the system will decide whether to add 2.0V or subtract 2.0V from the current voltage to obtain the new voltage value. This decision is usually made in a certain logical sequence or in a random manner, with the purpose of testing the impact of voltage adjustments in different directions on power.

[0120] S52: Adjust the operating point to the new voltage value

[0121] After obtaining the new voltage value, the system adjusts the PV array's operating point to this new voltage by controlling devices such as the inverter. This process involves precise control of the PV array's output circuit to ensure stable operation at the newly set voltage. Adjusting the operating point changes the PV array's output current and voltage combination, which in turn affects its output power.

[0122] S53: Comparing power changes

[0123] After the PV array operating point stabilizes at the new voltage value, the system measures the output power at that point and obtains the new power value. This new power value is then compared with the power value before the voltage disturbance. The comparison result determines the subsequent operation direction. If the new power value is greater than the power value before the disturbance, the current voltage adjustment direction is correct and can bring the PV array closer to the maximum power point. Conversely, if the new power value is less than the power value before the disturbance, the adjustment direction is incorrect and needs to be changed.

[0124] In the above technical solution, by continuously applying voltage perturbations and comparing power changes, the system can gradually locate the maximum power point of the photovoltaic array. Each perturbation acts as a trial, and the correct adjustment direction is determined based on the power fluctuations, thereby continuously optimizing the operating point. When environmental factors such as light intensity and temperature change, this dynamic adjustment mechanism allows the photovoltaic array to quickly adapt to these changes, consistently maintaining operation near the maximum power point, improving solar energy conversion efficiency and increasing power generation. Furthermore, this method is independent of specific photovoltaic array models or environmental conditions, making it highly adaptable. This power comparison-based perturbation adjustment method can track the maximum power point regardless of the array type or lighting and temperature conditions. As long as the power fluctuation can be measured, accurate adjustments can be made based on the comparison results, ensuring stable system operation in a variety of complex environments. By gradually adjusting the voltage in small increments, each time changing only one perturbation step, significant impacts on the photovoltaic array's operating point are avoided, reducing system fluctuations and instability. When approaching the maximum power point, a smaller disturbance step size can make the system stay near the maximum power point more stably, and will not cause a significant drop in power due to excessive adjustment, thus ensuring the stability of the photovoltaic system's output power.

[0125] In another specific embodiment of the present invention, the flow channel is bonded to the back of the photovoltaic panel 1 through thermal conductive silicone, with a bonding thickness of 0.5 mm and a coverage rate of ≥95%. A flow channel outlet joint is provided at the end of each thermal flow channel, which is connected to the stainless steel corrugated hose by a thread; each stainless steel corrugated hose is collected into a stainless steel header through a multi-way header interface, and the header is connected to the inlet of the first-stage heat exchanger 2 through a flange.

[0126] In the above technical solution, the thermal conductive channel is bonded to the back of the photovoltaic panel 1 with thermally conductive silicone adhesive, with a thickness of 0.5 mm and a coverage ratio of ≥95%. The thermally conductive silicone adhesive has excellent thermal conductivity, effectively transferring waste heat generated by the photovoltaic panel 1 to the heat-conducting medium within the thermal conductive channel. The 0.5 mm adhesive thickness is optimized to ensure sufficient heat transfer area without increasing thermal resistance due to excessive thickness, which would affect heat transfer efficiency. The high coverage ratio means that the thermal conductive channel has a large contact area with the photovoltaic panel 1, maximizing the collection of waste heat generated by the panel and ensuring efficient waste heat recovery. Each thermal conductive channel is terminated with a channel outlet connector, which is threadedly connected to a stainless steel corrugated hose. The channel outlet connector provides a channel for the heat-conducting medium to flow out of the thermal conductive channel. The threaded connection provides excellent sealing and connection strength, preventing leakage of the heat-conducting medium and ensuring normal operation of the system. The stainless steel corrugated hose is flexible and corrosion-resistant, adapting to different installation environments and location variations, facilitating system layout and connection. Each stainless steel corrugated hose is aggregated into a stainless steel manifold through a multi-way manifold interface. The multi-way manifold interface can aggregate the heat-conducting media in multiple stainless steel corrugated hoses together to achieve the aggregation of multi-path heat-conducting media. The stainless steel manifold has good strength and corrosion resistance, can withstand a certain pressure, and ensure the stable flow of the heat-conducting medium during the aggregation process. The manifold is connected to the inlet of the first-stage heat exchanger 2 through a flange. Flange connection is a commonly used pipeline connection method with the advantages of tight connection, good sealing performance, and easy disassembly and maintenance. Through the flange connection, the stainless steel manifold can be firmly connected to the first-stage heat exchanger 2, and the aggregated heat-conducting medium is transported to the heat exchanger for heat exchange.

[0127] like Figure 1 or Figure 2 In another specific embodiment of the present invention, the first-stage heat exchanger 2 and the second-stage heat exchanger 5 are both shell and tube heat exchangers, each comprising a shell, two independent tube passes, and a shell pass;

[0128] The outlet of the heat transfer channel is connected to the inlet of the first set of tubes of the first-stage heat exchanger 2. After the heat transfer medium has completed the heat exchange, it flows out of the outlet of the first set of tubes and enters the first set of independent tubes of the next-stage heat exchanger 5. After passing through the Y-shaped diverter pipe, it is finally distributed to the inlet of the heat transfer channel of each photovoltaic panel 1 to achieve circulation.

[0129] The condenser outlet of the heat pump is connected to the second tube side inlet of the first stage heat exchanger 2. The refrigerant that has completed the heat exchange flows out from the second tube side outlet of the first stage heat exchanger 2, passes through the electronic expansion valve, and returns to the evaporator inlet of the heat pump to complete the cycle.

[0130] The outlet end of the shell side of the first-stage heat exchanger 2 is connected with the liquid inlet of the first-stage temperature demand user end 3, the liquid outlet of the first-stage temperature demand user end 3 is firstly connected with the second-group tube side inlet of the second-stage heat exchanger 5, then passes through the second-group tube side outlet of the second-stage heat exchanger 5, and is connected with the liquid inlet of the shell side of the second-stage heat exchanger 5.

[0131] The outlet end of the shell side of the second-stage heat exchanger 5 is connected with the liquid inlet of the second-stage temperature demand user end, and the liquid outlet of the second-stage temperature demand user end is connected with the inlet end of the shell side of the first-stage heat exchanger 2, so that the circulation is realized.

[0132] In the above technical scheme, the first-stage heat exchanger 2 and the second-stage heat exchanger 5 are both shell-and-tube heat exchangers, which are composed of a shell, two independent tube sides and a shell side. The tube side refers to the channel in which the fluid flows in the pipe, and the shell side refers to the channel in which the fluid flows between the shell and the pipe. The two independent tube sides can make different fluids flow in the heat exchanger, so that multiple heat exchange processes are realized.

[0133] In the above technical solution, the heat transfer medium flows out of the heat transfer channel outlet of the photovoltaic panel 1 and enters the first set of tube-side inlets of the first-stage heat exchanger 2. Within this first set of tube-sides, the heat transfer medium exchanges heat with the fluid in the shell side, releasing waste heat absorbed from the photovoltaic panel 1. The heat transfer medium, having completed the heat exchange, flows out of the first set of tube-side outlets and then enters the first set of independent tube-sides of the next-stage heat exchanger 5 for further heat exchange. After passing through the next-stage heat exchanger 5, the heat transfer medium is redistributed to the heat transfer channel inlets of each photovoltaic panel 1 via a Y-shaped manifold (which can also be replaced with a multi-head manifold depending on the number of photovoltaic panels 1), completing a cycle and continuing to absorb waste heat generated by the photovoltaic panels 1. The heat pump's condenser outlet discharges high-temperature, high-pressure refrigerant and enters the second tube-side inlet of the first-stage heat exchanger 2. In the second tube side, the refrigerant exchanges heat with the fluid in the shell side, and the temperature drops after releasing heat; the refrigerant that has completed the heat exchange flows out from the second tube side outlet of the first-stage heat exchanger 2, passes through the electronic expansion valve, and the electronic expansion valve throttles and reduces the pressure of the refrigerant, making it a low-temperature and low-pressure state; the reduced-pressure refrigerant returns to the evaporator inlet of the heat pump, absorbs ambient heat in the evaporator, and becomes a high-temperature and high-pressure refrigerant again, completing a cycle. The hot fluid flowing out of the shell-side outlet of the first-stage heat exchanger 2 enters the liquid inlet of the first-stage temperature-demanding user end 3 to provide heat for the user end; the liquid after use by the first-stage temperature-demanding user end 3 flows out from the liquid outlet and first enters the second group of tube-side inlets of the next-stage heat exchanger 5, and exchanges heat with the fluid in the shell side in the tube side to further release waste heat; after flowing out from the second group of tube-side outlets of the next-stage heat exchanger 5, the liquid enters the shell-side liquid inlet of the next-stage heat exchanger 5 to exchange heat again; the liquid flowing out of the shell-side outlet of the next-stage heat exchanger 5 enters the liquid inlet of the second-stage temperature-demanding user end to provide lower temperature heat for the user end; the liquid after use by the second-stage temperature-demanding user end flows out from the liquid outlet and is connected to the shell-side inlet of the first-stage heat exchanger 2 to complete a cycle.

[0134] In the above technical solution, by combining the circulation of a heat transfer medium with the circulation of liquid at the user end, the waste heat generated by the photovoltaic panels 1 is fully recovered and transferred to users with different temperature requirements, achieving a cascaded heat utilization. This approach improves the overall energy utilization rate and reduces energy waste. The combination of the heat pump and heat exchanger allows the effective use of ambient heat, further increasing the system's heat supply and improving the overall energy efficiency. The two independent tube-side and shell-side structures allow different fluids to exchange heat independently within the heat exchanger. This allows the system to flexibly adjust the degree of heat exchange based on the temperature requirements of different users, achieving precise heating for users with different temperature requirements. For example, the first-level temperature requirement user 3 requires higher temperature heat, while the second-level temperature requirement user can utilize waste heat. By rationally designing the heat exchange process, the diverse needs of different users can be met. More importantly, the system design is highly scalable, allowing the number of photovoltaic panels 1, heat pumps, heat exchangers, and other equipment to be increased or decreased according to actual needs to adapt to energy demands of varying scales. At the same time, for users with different temperature requirements, the requirements can be met by adjusting the heat exchange process and parameters, which has strong adaptability.

[0135] like Figure 2 In another specific embodiment of the present invention, the photovoltaic heat recovery and reuse system further includes a thermal energy storage mechanism 7, which is used to store excess heat from the multi-stage heat exchange unit to provide heat during peak heat demand or when the heat pump unit 4 is insufficiently supplying heat. The core function of the thermal energy storage mechanism 7 is to store excess heat generated by the multi-stage heat exchange unit. During operation of the photovoltaic heat recovery and reuse system, the multi-stage heat exchange unit continuously exchanges heat. Sometimes, the amount of heat generated exceeds the user's immediate heat demand. In this case, the excess heat is collected and stored by the thermal energy storage mechanism 7 via a Y-shaped shunt pipe. A solenoid valve is provided between the thermal energy storage mechanism 7 and the multi-stage heat exchange unit. When the heat generated by the multi-stage heat exchange unit exceeds the user's current heat demand, the solenoid valve opens, and the thermal energy storage mechanism 7 begins to operate, storing the excess heat. Otherwise, the solenoid valve closes. During certain time periods, such as winter evenings or during business hours in large commercial venues, the user's demand for heat can increase significantly, exceeding the immediate heating capacity of the multi-stage heat exchange unit and the heat pump unit 4. At this time, the heat storage mechanism 7 will release the stored heat and add it to the heating system to meet the heat demand of the user end; or when the heating capacity of the heat pump unit 4 decreases due to reasons such as low ambient temperature or equipment failure, the heat storage mechanism 7 will play a role, release the stored heat, maintain the heating stability of the system, and ensure normal heat use at the user end.

[0136] In the above technical solution, the heat storage and energy storage mechanism 7 is provided to enable the system to effectively utilize the excess heat generated by the multi-stage heat exchanger set, avoiding waste of heat. When heat is generated in excess, it is stored, and when demand peaks, it is released, achieving rational allocation of heat and improving the energy utilization efficiency of the entire photovoltaic heat recycling system. In the case of high heat demand or insufficient heat supply of the heat pump set 4, the heat storage and energy storage mechanism 7 can provide supplemental heat in time to ensure that the heat demand of the user end is met. This greatly enhances the stability and reliability of the system and reduces the impact on normal life or production due to insufficient heat supply. For example, in cold winter nights, even if the heat pump set 4 has reduced heat supply due to low ambient temperature, the heat storage and energy storage mechanism 7 can ensure that the indoor temperature remains within a comfortable range. The operation of the photovoltaic heat recycling system is affected by many factors such as light intensity and ambient temperature, and the heat demand of the user end also changes with time and season. The presence of the heat storage and energy storage mechanism 7 enables the system to better adapt to these working conditions and environmental changes, ensuring stable operation of the system under various conditions and improving the adaptability and flexibility of the system. By reasonably utilizing the heat storage and energy storage mechanism 7, the system can store heat during periods of low electricity prices (such as at night) and reduce dependence on grid power during periods of high electricity prices (such as during daytime peak electricity demand), thereby reducing the operating cost of the system. In addition, the heat storage and energy storage mechanism 7 can also reduce the frequent start-stop of the heat pump set 4 and other equipment, prolong the service life of the equipment, and reduce equipment maintenance costs.

[0137] The number of devices and the scale of processing described herein are used to simplify the description of the present application. It is obvious to those skilled in the art that the application of the photovoltaic heat recycling system of the present application, modifications and changes are obvious.

[0138] Although the embodiments of the present application have been disclosed as above, they are not limited to the applications listed in the specification and embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily realized by those skilled in the art, therefore the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and equivalent scope.

Claims

1. Photovoltaic heat recovery and reuse system, characterized in that: include: Photovoltaic array, which includes several photovoltaic panels, multiple photovoltaic panels are arranged in a matrix, and each photovoltaic panel is provided with a spiral heat conduction channel on the back; Heat pump units, driven by electricity generated by photovoltaic arrays, are used to absorb heat from the environment and supply it to users with different temperature requirements; A two-stage heat exchange unit, comprising two heat exchangers of different temperature levels, is used to absorb and utilize waste heat generated by photovoltaic panels, as well as to recover waste heat generated by users with different temperature requirements in a cascaded manner and supply it to users with the next higher temperature requirements; The heat pump unit absorbs heat from the environment and transmits it to the first-stage temperature demand user end through the first-stage heat exchanger. The first-stage heat exchanger receives the waste heat generated by the photovoltaic panels. The residual heat of the first-stage temperature demand user end is transmitted to the second-stage temperature demand user end through the second-stage heat exchanger. The second-stage heat exchanger receives the residual heat discharged by the first-stage heat exchanger. The first-stage heat exchanger and the second-stage heat exchanger are both shell and tube heat exchangers, each comprising a shell, two independent tube passes, and a shell pass; The outlet of the heat transfer channel is connected to the inlet of the first set of tubes of the first-stage heat exchanger. After the heat transfer medium has completed the heat exchange, it flows out of the outlet of the first set of tubes and enters the first set of independent tubes of the next-stage heat exchanger. After passing through the Y-shaped diverter pipe, it is finally distributed to the inlet of the heat transfer channel of each photovoltaic panel to achieve circulation. The condenser outlet of the heat pump is connected to the second tube side inlet of the first stage heat exchanger. The refrigerant that has completed the heat exchange flows out from the second tube side outlet of the first stage heat exchanger, passes through the electronic expansion valve, and returns to the evaporator inlet of the heat pump to complete the cycle. Connect the shell-side outlet of the first-stage heat exchanger to the liquid inlet of the first-stage temperature demand user end. The liquid outlet of the first-stage temperature demand user end is first connected to the second set of tube-side inlet of the next-stage heat exchanger, and then connected to the shell-side liquid inlet of the next-stage heat exchanger through the second set of tube-side outlet of the next-stage heat exchanger. The outlet end of the shell side of the next-stage heat exchanger is connected to the liquid inlet of the second-stage temperature demand user end, and the outlet of the second-stage temperature demand user end is connected to the inlet end of the shell side of the first-stage heat exchanger to realize circulation.

2. The photovoltaic heat recovery and reuse system according to claim 1, characterized in that: A heat-conducting medium flows in the heat-conducting channel, and the heat-conducting medium absorbs waste heat generated by the photovoltaic panel and transfers the heat to the first-stage heat exchanger.

3. The photovoltaic heat recovery and reuse system according to claim 1, characterized in that: The photovoltaic array is formed by connecting n solar panels in series and m groups of solar panels in parallel; The output of the PV array is connected to a DC combiner box, which aggregates the DC outputs of m groups of series-connected solar panels. The DC power output by the DC combiner box is then connected to an inverter with maximum power point tracking (MPPT). The maximum power point tracking function is implemented as follows: S1. Divide the operating voltage range into multiple intervals, including a low voltage zone, a medium voltage zone, and a high voltage zone, based on the theoretical upper limit open circuit voltage of the output voltage of the photovoltaic array; S2. Set different perturbation step sizes in each interval, where the perturbation step size in the low voltage area is larger than that in the medium voltage area, and the perturbation step size in the medium voltage area is larger than that in the high voltage area; S3, real-time monitoring of the output voltage and current of the photovoltaic array, and calculation of the current power; S4. Determine the interval to which the current voltage belongs based on the current voltage value and select the corresponding disturbance step size; S5. Apply voltage disturbance, adjust the operating point of the photovoltaic array, and compare the power changes before and after the disturbance; if the power increases, maintain the disturbance direction; if the power decreases, reverse the disturbance direction; S6. Repeat the above steps until the photovoltaic array operates at the maximum power point.

4. The photovoltaic heat recovery and reuse system according to claim 3, characterized in that: According to the theoretical upper limit of the output voltage of the photovoltaic array, the open-circuit voltage, the operating voltage range is divided into several intervals as follows: Low voltage area: 0~50% of open circuit voltage; Medium voltage region: 50%~80% of the open circuit voltage; and, High voltage area: 80%~100% of the open circuit voltage.

5. The photovoltaic heat recovery and reuse system according to claim 3, characterized in that: Setting different perturbation step sizes in each interval includes: The step size in the low voltage region is 2.0V; The step size in the medium voltage region is 1.0V; The step size in the high voltage region is 0.5V.

6. The photovoltaic heat recovery and reuse system according to claim 3, characterized in that: The steps of applying voltage disturbance, adjusting the operating point of the photovoltaic array, and comparing power changes before and after the disturbance in step S5 include: S51, increasing or decreasing a disturbance step size based on the current voltage to obtain a new voltage value; S52, adjusting the operating point of the photovoltaic array to a new voltage value; S53. Measure the new power value and compare it with the power value before the disturbance.

7. The photovoltaic heat recovery and reuse system according to claim 2, characterized in that: The heat-conducting channel is bonded to the back of the photovoltaic panel through thermally conductive silicone, with a bonding thickness of 0.5 mm and a coverage rate of ≥95%. A channel outlet joint is provided at the end of each heat-conducting channel, which is connected to the stainless steel corrugated hose through a thread; each stainless steel corrugated hose is collected into a stainless steel header through a multi-way header interface, and the header is connected to the inlet of the first-stage heat exchanger through a flange.

8. The photovoltaic heat recovery and reuse system according to claim 1, characterized in that: It also includes a heat storage mechanism, which is used to store excess heat from the multi-stage heat exchange unit to provide heat when heat demand peaks or when the heat pump unit is insufficient.

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