Greenhouse heat storage and heat preservation system based on photovoltaic photo-thermal and working method of greenhouse heat storage and heat preservation system

Abstract

The invention discloses a greenhouse heat storage and insulation system based on photovoltaic photo-thermal and a working method thereof, and belongs to the field of comprehensive utilization of solar photoelectric and photo-thermal technologies. According to the system, heat generated by photovoltaic power generation is taken away and directly used as a heat source of the heat storage water tank, and the electric load and investment cost of photovoltaic power generation are reduced. The heat storage water tank and the electric heating water tank are adopted, so that solar photovoltaic photo-thermal in the daytime is used for heat preservation at night. According to the structural characteristics of the greenhouse, a phase change heat collection plate is arranged on the north wall, reasonable matching between photovoltaic electric energy and photo-thermal heat energy is achieved by increasing photo-thermal heat, and efficient utilization of the greenhouse space is achieved by utilizing the vertical wall space of the north wall; the drip irrigation device is also used for crop root heat preservation, and the heat transfer efficiency and the heat preservation effect are improved.

Description

Technical Field

[0001] The invention relates to a greenhouse heat storage and insulation system based on photovoltaic and thermal energy and a working method thereof, and belongs to the field of comprehensive utilization of solar photovoltaic and thermal energy technologies. Technical Background

[0002] With the continuous development of science and technology, the traditional agricultural production model can no longer meet the needs of the development of modern civilization. As a new type of agricultural facility, greenhouses have attracted much attention due to their green, low-carbon, low price and wide application range. In winter in cold areas or at night with low temperatures, the greenhouse cannot meet the temperature required for crop growth by relying solely on solar energy. Biomass heating, coal heating and electric heating are needed to ensure the normal growth of crops in the greenhouse. These heating methods increase fuel costs, labor costs and equipment costs. The combustion of biomass and coal will also bring safety hazards and environmental pollution. Therefore, it is necessary to develop low-cost greenhouse heating methods.

[0003] Solar energy is a clean and efficient renewable energy source. Among its various utilization methods, solar photovoltaic power generation and solar thermal utilization are the main development directions of solar energy utilization. The efficiency of solar photovoltaic power generation is low. Usually, the efficiency of photovoltaic cells is less than 15%, which means that most sunlight is reflected or converted into heat. The output power of solar crystalline silicon cells will decrease as their own temperature increases. For every 1°C increase, the power generation efficiency decreases by about 0.3%. Solar photovoltaic thermal technology combines photovoltaic cells with solar thermal collection technology, and uses the cooling medium in the thermal collection component to take away the heat of solar photovoltaic panels and utilize it. While improving the efficiency of photovoltaic power generation, it also utilizes the thermal energy of sunlight. The quality of this part of the collected light and heat is low, below 50°C. How to efficiently use light and heat resources for greenhouse insulation has become an urgent problem to be solved.

[0004] The invention patent of CN104025947B discloses a self-circulating greenhouse, which uses rainwater as the heat transfer medium of the photovoltaic and thermal components, and realizes the thermal circulation and electric energy self-sufficiency of the greenhouse through the insulation front wall and the underground insulation layer; the invention patent of CN114600678A discloses a photovoltaic and thermal integrated greenhouse, which receives sunlight through multiple vacuum heat collecting tubes on the top of the greenhouse to avoid the continuous increase of the temperature in the greenhouse and stores excess heat through water bodies, and dissipates heat when the temperature drops at night to maintain the temperature in the greenhouse; the utility model patent of CN209359161U discloses an energy-saving greenhouse constant temperature system, which connects the interior of the greenhouse with the interior of the heat pump unit body and forms a circulating air path, which can meet the constant temperature requirements of cooling and heating in the greenhouse and ensure the normal operation of the heat pump unit; the invention patent of CN106613531B provides a photovoltaic and thermal integrated circulation system for greenhouses that can realize the switching of seasonal operation modes and improve the heat utilization efficiency, uses a heat pump unit, and does not require external auxiliary heating equipment to realize the self-supply of heat and electric energy.

[0005] The problems of the above photovoltaic thermal greenhouses are as follows: (1) The starting point of photovoltaic thermal design is to reduce the temperature of photovoltaic panels and thus improve the efficiency of photovoltaic power generation. It is not to design the photovoltaic thermal system around the heat storage and insulation of the greenhouse. The result is that photovoltaic power generation can meet the greenhouse's self-sufficiency in electricity, but cannot meet the greenhouse's self-sufficiency in heat insulation. It is necessary to add solar thermal collection technology that is suitable for the structural characteristics of the greenhouse.

[0006] (2) The economic efficiency of using heat pump technology to use solar thermal energy for greenhouse insulation is not high. The heat pump unit consumes high-quality electricity to upgrade low-quality solar thermal energy for greenhouse insulation, which deviates from the energy utilization principle of "energy use according to quality". The result is high energy consumption for greenhouse insulation and a significant increase in the investment cost of photovoltaic power generation.

[0007] (3) When the sunlight is strong during the day, the greenhouse does not need to be kept warm or the electricity and solar thermal energy consumed by the heat preservation are relatively small. Photovoltaic thermal energy is mainly used for greenhouse insulation at night. Photovoltaic power generation during the day is difficult to store at low cost to drive heat pumps at night, and the collected solar thermal energy is difficult to use for greenhouse insulation at night. There is a lack of reasonable matching between photovoltaic power and solar thermal energy to achieve efficient heat storage and insulation in the greenhouse.

[0008] (4) Hot air is often used as a medium to keep crops in the greenhouse warm by air convection. As a result, hot air flows upward from the stems of the crops. The hot air does not act on the roots of the crops, which need insulation the most. The insulation has a poor effect on crop growth, and there is a lack of insulation and heat transfer methods that are tailored to the particularities of greenhouse cultivation. Summary of the invention

[0009] The purpose of the present invention is to overcome the existing technical defects and provide a photovoltaic-thermal integrated heat storage and insulation system that alternately operates heat collection, heat storage and electric auxiliary heating to improve photovoltaic power generation efficiency and heat utilization efficiency. The system takes greenhouse insulation as the design starting point, takes away the heat generated by photovoltaic power generation and directly uses it as a heat source for the heat storage water tank, reducing the electrical load and investment cost of photovoltaic power generation; adopts a heat storage water tank and an electric heating water tank to realize the use of daytime solar photovoltaic heat for nighttime insulation; adopts a phase change collector plate on the north wall to achieve a reasonable match between photovoltaic electricity and photothermal heat energy by increasing the photothermal heat, ensures efficient heat storage and insulation of the greenhouse, and utilizes the vertical wall space of the north wall to achieve efficient utilization of the greenhouse space, which is suitable for the heat collection technology with the structural characteristics of the greenhouse; uses a drip irrigation device to keep the roots of crops warm, thereby improving the heat transfer efficiency and insulation effect.

[0010] The present invention is achieved through the following technical solutions: A greenhouse heat storage and insulation system based on photovoltaic thermal energy, the system comprising a heat storage device, a phase change heat collection device, a drip irrigation device, a geothermal device, a photovoltaic thermal assembly and a roller shutter; The hot water storage tank in the heat storage device is connected to the photovoltaic thermal assembly via a photovoltaic regulating valve and a photovoltaic circulation pump in sequence, and then connected back to the hot water storage tank via a pipeline; The phase change heat collecting plate in the phase change heat collecting device is composed of a heat absorbing plate, a binder, a solid phase change layer, a fluid channel and a heat insulation layer in sequence; the heat storage tank is connected to the inlet end of the fluid channel through a heat collecting regulating valve and a heat collecting circulation pump in sequence, and the outlet end of the fluid channel is connected back to the heat storage tank through a pipeline; The electric heating water tank in the geothermal device is connected to one end of the geothermal pipe via a geothermal circulation pump and a geothermal front valve in sequence, and the other end of the geothermal pipe is connected back to the electric heating water tank via a pipeline via a geothermal rear valve; The drip irrigation water tank in the drip irrigation device is connected to the geothermal pipe via a drip irrigation circulation pump and a drip irrigation regulating valve in sequence, the drip irrigation outlet of the geothermal pipe is connected to the drip irrigation inlet, the pipe section connected to the drip irrigation inlet is provided with an electromagnetic shutoff valve and a drip irrigation port, and a spray port is provided at the end of the pipe; A heat conducting plate 9 is arranged between the hot water storage tank and the electric heating water tank.

[0011] The photovoltaic thermal assembly is electrically connected to an electric heating water tank, a photovoltaic circulation pump, a heat collection circulation pump, a geothermal circulation pump, a drip irrigation circulation pump, a roller shutter machine, a lighting lamp, and a storage battery.

[0012] The outer layers of the water storage tank and the electric heating tank are provided with aerogel insulation material.

[0013] A working method of a greenhouse heat storage and insulation system based on photovoltaic thermal energy comprises the following steps: a. The photovoltaic thermal component is connected to a water storage tank, and the paraffin solution / graphene oxide phase change fluid therein exchanges heat when flowing through the photovoltaic thermal component, and the heat taken away is stored in the water storage tank; b. The phase change collector is connected to the hot water storage tank. The heat absorption layer in the phase change collector absorbs the heat from solar radiation and is stored in the solid phase change layer. When the paraffin solution / graphene oxide phase change fluid in the hot water storage tank flows through the fluid channel, heat exchange is performed, and the heat is brought to the hot water storage tank 2 for storage; c. The hot water storage tank exchanges heat with the water in the electric heating water tank through the heat conduction plate to preliminarily heat the water in the electric heating water tank; d. The electric heating water tank is connected to the geothermal pipe. The temperature control system in the electric heating water tank automatically heats the water preheated by the heat storage tank to the required water temperature according to the temperature requirements in the greenhouse. e. The water in the electric heating water tank is transported to the geothermal pipe through a water pump, and the heat is transferred to the vegetation layer through the geothermal pipe; f. The drip irrigation water tank, geothermal pipe and drip irrigation device are connected, the electromagnetic shutoff valve of the drip irrigation device is opened, the opening of the drip irrigation port is adjusted, and the water in the drip irrigation water tank is drip-irrigated to the vegetation through the geothermal pipe and the drip irrigation device; g. When the temperature in the greenhouse is too high, rotate and open the spray nozzle to perform direct evaporative cooling.

[0014] A working mode of greenhouse heat storage and insulation system based on photovoltaic thermal energy: i) Daytime operation mode in clear weather: Open the photovoltaic regulating valve and the heat collecting regulating valve, close the geothermal front valve, geothermal rear valve and drip irrigation regulating valve, and the phase change fluid at 20-25°C in the photovoltaic thermal assembly and the phase change collector plate will be heated to 35-40°C after being irradiated by sunlight. The heated phase change fluid will be transported to the hot water storage tank for storage through the photovoltaic circulation pump and the heat collecting circulation pump; ii) Night operation mode where temperature requirements are not high: Open the heat collection regulating valve and heat collection water pump, close the photovoltaic regulating valve, geothermal front valve, geothermal rear valve and drip irrigation regulating valve, and the 30-35℃ low-temperature phase change fluid in the heat storage tank transfers heat to the phase change collector plate, which transfers heat to the greenhouse through convection heat transfer; iii) Operation mode with low temperature and insufficient sunlight: Open the geothermal front valve and geothermal rear valve, close the photovoltaic regulating valve, heat collection regulating valve and drip irrigation regulating valve, and the water in the electric heating water tank absorbs the heat in the heat storage tank to become low-temperature hot water of 30℃±5℃, which is further heated to the set temperature by electric heating. The geothermal circulation valve transports the heated water to the geothermal pipe, and the heat is dissipated to the vegetation layer through the geothermal pipe; iv) Nighttime operation mode when the temperature is low and the daytime sunlight is sufficient: Open the heat collection regulating valve, geothermal front valve, and geothermal rear valve, and close the photovoltaic regulating valve and drip irrigation regulating valve. The heat in the hot water storage tank and the electric heating tank is transferred to the greenhouse through the phase change collector plate and geothermal pipe respectively. v) Drip irrigation mode: Open the drip irrigation regulating valve, close the geothermal front valve and geothermal rear valve, open the electromagnetic shut-off valve of the drip irrigation device, adjust the opening of the drip irrigation port, and the water in the drip irrigation tank drips the vegetation through the geothermal pipe and the drip irrigation device; when the temperature in the greenhouse is too high, rotate to open the spray port of the drip irrigation device for direct evaporative cooling.

[0015] Furthermore, the geothermal pipe plays the role of both transferring heat and irrigating. When irrigating, the valve connected to the electric heating water tank is closed, the valve connected to the drip irrigation water tank is opened, the electromagnetic valve of the drip irrigation device is opened, and the water pump sends the water in the drip irrigation tank to the drip irrigation device for irrigation; when transferring heat, the valve connected to the drip irrigation water tank is closed, the valve connected to the electric heating water tank is opened, and the heated water is sent to the geothermal pipe by the water pump for heat exchange.

[0016] The phase change collector is connected to the hot water tank through a water pump to collect heat from solar radiation and heat the fluid medium in the hot water tank. At night or during the day when the light is insufficient, the phase change collector can also act as a heat sink to transfer the heat in the hot water tank to the shed through convection heat exchange.

[0017] Furthermore, the photovoltaic thermal assembly is placed at the rear of the greenhouse, which does not hinder the operation of the greenhouse, does not cause shading to the vegetation in the greenhouse, and is convenient for disassembly and maintenance; the back of the photovoltaic panel is a grid-type fluid channel made of a blown aluminum plate process, which improves the heat transfer efficiency; Furthermore, the fluid medium in the photovoltaic thermal assembly, the phase change collector plate and the hot water storage tank is a paraffin solution / graphene oxide composite phase change material, which has better thermal conductivity and higher thermal storage density than water; Furthermore, the outside of the water storage tank and the electric heating tank is provided with aerogel insulation material, and the electric heating tank is provided with a temperature control system, which automatically heats the water to the required temperature according to the temperature requirements in the shed; Furthermore, the drip irrigation device is connected to the geothermal pipe through a rubber head, and there is a solenoid valve behind the interface that controls the opening and closing. It is connected to the drip irrigation rod through a water hose. The drip irrigation rod can be placed according to the position of the vegetation, and the cone head at the bottom is inserted into the soil to fix it. The drip irrigation rod has an adjustable drip irrigation port, and there is a rotating spray nozzle on the top of the drip irrigation rod. When the temperature in the greenhouse is too high, it is cooled by direct evaporative cooling.

[0018] The beneficial effects of the present invention are: (1) No external electricity or fuel consumption is required. The greenhouse can be insulated by using solar photovoltaic power generation and solar thermal heat, which greatly reduces the cost of greenhouse insulation.

[0019] (2) Photovoltaic electricity and solar thermal energy are reasonably matched according to the requirements of greenhouse insulation. The solar thermal energy generated by photovoltaic power generation and the low-quality solar thermal energy of phase change collectors are used as the main heat sources for greenhouse insulation. The collected solar thermal energy does not need to consume high-quality electricity but is directly stored in a water storage tank for greenhouse insulation. The photovoltaic power generation heats the electric heating tank to assist in greenhouse insulation. The solar thermal energy and photovoltaic energy are stored in the water storage tank and the electric heating tank respectively, realizing the low-cost use of daytime solar energy for greenhouse insulation at night.

[0020] (3) Taking advantage of the large vertical space of the north wall and the direct contact of the drip irrigation device with the roots of crops, a photothermal insulation technology suitable for greenhouses was developed. Phase change collectors were arranged on the vertical wall of the north wall, which can not only make full use of sunlight to improve the efficiency of photothermal collection, but also save space for crop planting in the greenhouse. The existing drip irrigation device was used as a geothermal pipe for greenhouse insulation. The heat was directly transferred to the roots of the crops, which improved the insulation effect and heat transfer rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of a greenhouse heat storage and insulation system based on photovoltaic thermal energy.

[0022] Figure 2 Schematic diagram of the phase change collector structure.

[0023] Figure 3 Schematic diagram of the drip irrigation device structure.

[0024] The reference numerals in the figure are: 1. Photovoltaic thermal component, 2. Heat storage tank, 201. Heat conduction plate, 3. Electric heating water tank, 4. Drip irrigation water tank, 5. Phase change collector plate, 501. Heat absorption plate, 502. Binder, 503. Solid phase change layer, 504. Fluid channel, 505. Insulation layer, 6. Geothermal pipe, 601. Drip irrigation outlet, 701. Photovoltaic circulation pump, 702. Heat collection circulation pump, 703. Geothermal circulation pump, 704. Drip irrigation circulation pump, 801. Photovoltaic regulating valve, 802. Heat collection regulating valve, 803. Geothermal front valve, 804. Drip irrigation regulating valve, 805. Geothermal rear valve, 901. Drip irrigation inlet, 902. Electromagnetic shut-off valve, 903. Drip irrigation port, 904. Spray port, 10. Roller shutter. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0026] like Figure 1As shown, the present invention proposes a greenhouse heat storage and insulation system based on photovoltaic thermal energy, including a photovoltaic thermal assembly 1, a water storage tank 2, an electric heating water tank 3, a drip irrigation water tank 4, a phase change collector plate 5, a geothermal pipe 6, a circulating water pump 7, a regulating valve 8, a drip irrigation device 9, and a roller shutter 10.

[0027] Specifically, the photovoltaic thermal component 1 is connected to the hot water storage tank 2, and the paraffin solution / graphene oxide phase change fluid therein takes away the heat from the back of the photovoltaic panel, reduces the temperature of the photovoltaic panel, and improves the power generation efficiency of the photovoltaic panel. The heat taken away is stored in the hot water storage tank 2.

[0028] The phase change collector plate 5 is connected to the hot water storage tank 2. The heat absorption layer 501 in the phase change collector plate 2 absorbs the heat from solar radiation and is stored by the solid phase change layer 502. When the paraffin solution / graphene oxide phase change fluid flows through the fluid channel 504, the heat is brought to the hot water storage tank 2 for storage. The hot water storage tank 2 stores the heat from the photovoltaic thermal assembly 1 and the phase change collector plate 5. The fluid medium therein exchanges heat with the water in the electric heating water tank 3 through the heat conducting plate 201, and preliminarily heats the water in the electric heating water tank 3. The hot water storage tank and the electric heating water tank are provided with aerogel insulation materials on the outside.

[0029] The electric heating water tank 3 is connected to the geothermal pipe 6. The electric heating water tank 3 has a temperature control system. According to the temperature requirements in the greenhouse, the water preheated by the heat storage tank 2 is automatically heated to the required water temperature. The required electricity comes from the photovoltaic panel. The treated water is transported to the geothermal pipe 6 by a water pump, and the heat is dissipated to the vegetation layer through the geothermal pipe 6. The geothermal pipe 6 is also connected to the drip irrigation water tank 4 and the drip irrigation device 9 to form a drip irrigation system. At this time, the electromagnetic shut-off valve 902 of the drip irrigation device is opened, and the drip irrigation port 903 is adjusted to a suitable opening. The water from the drip irrigation water tank 4 drips the vegetation through the heat pipe and the drip irrigation device. When the temperature in the greenhouse is too high, the spray port 904 of the drip irrigation device is rotated to open for direct evaporative cooling.

[0030] The system has a stable and energy-saving operation mode, which can effectively maintain a constant temperature in the greenhouse according to the changes in the outside temperature. There are multiple operation modes in the greenhouse: i) Daytime operation mode in clear weather: The photovoltaic regulating valve 801 and the heat collecting regulating valve 802 are opened, and the geothermal front valve 803, the geothermal rear valve 805 and the drip irrigation regulating valve 804 are closed. The phase change fluid at 20-25°C in the photovoltaic thermal assembly 1 and the phase change collector plate 5 is heated to 35-40°C after being irradiated by sunlight. The heated phase change fluid is transported to the hot water storage tank 2 for storage through the photovoltaic circulation pump 701 and the heat collecting circulation pump 702; ii) Night operation mode where temperature requirements are not high: Open the heat collection regulating valve 802 and the heat collection water pump 702, close the photovoltaic regulating valve 801, the geothermal front valve 803, the geothermal rear valve 805 and the drip irrigation regulating valve 804, and the 30-35°C low-temperature phase change fluid in the hot water storage tank 2 transfers heat to the phase change heat collection plate 5, and the phase change heat collection plate 5 transfers heat to the greenhouse through convection heat exchange; iii) Operation mode with low temperature and insufficient sunlight: Open the geothermal front valve 803 and the geothermal rear valve 805, close the photovoltaic regulating valve 801, the heat collecting regulating valve 802 and the drip irrigation regulating valve 804, and the water in the electric heating water tank 3 absorbs the heat in the water storage tank 2 to become low-temperature hot water of 30°C±5°C, and is further electrically heated to the set temperature. The geothermal circulation valve 703 transports the heated water to the geothermal pipe 6, and the heat is dissipated to the vegetation layer through the geothermal pipe 6; iv) Nighttime operation mode when the temperature is low and the daytime sunlight is sufficient: Open the heat collecting regulating valve 802, the geothermal front valve 803, and the geothermal rear valve 805, close the photovoltaic regulating valve 801 and the drip irrigation regulating valve 804, and the heat in the hot water storage tank 2 and the electric heating water tank 3 is transferred to the greenhouse through the phase change collector plate 5 and the geothermal pipe 6 respectively; v) Drip irrigation mode: Open the drip irrigation regulating valve 804, close the geothermal front valve 803 and the geothermal rear valve 805, open the electromagnetic shut-off valve 902 of the drip irrigation device, adjust the opening of the drip irrigation port 903, and the water in the drip irrigation tank 4 drips the vegetation through the geothermal pipe 6 and the drip irrigation device in turn; when the temperature in the greenhouse is too high, rotate and open the spray port 904 of the drip irrigation device to perform direct evaporative cooling.

[0031] When the temperature outside the greenhouse is low, the roller shutter machine 10 will lower the thermal blanket to cover the outside of the greenhouse to reduce heat loss in the greenhouse.

[0032] The electricity generated by the photovoltaic panels is used to power the heating water tank, water pump, lighting and roller shutter machines, and the excess electricity is stored in batteries.

[0033] In this embodiment, the operation and control systems of all circulation pumps and all regulating valves, electric heating water tanks 3 and electromagnetic shut-off valves 902 are fully automatic control systems, which can automatically adjust the system operation according to various monitoring signal feedbacks. The pipelines are equipped with antifreeze devices, which will automatically start the antifreeze heating belts in severe cold seasons or at nights with low temperatures.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art can still modify the technical solutions recorded in the above embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

[0035] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned technical means, but also include technical schemes composed of any combination of the above technical features.

Claims

1. A greenhouse heat storage and insulation system based on photovoltaic thermal energy, characterized by: The system comprises a heat storage device, a phase change heat collection device, a drip irrigation device, a geothermal device, a photovoltaic thermal assembly (1) and a roller blind (10); The hot water storage tank (2) in the heat storage device is connected to the photovoltaic thermal assembly (1) via a photovoltaic regulating valve (801) and a photovoltaic circulation pump (701) in sequence, and then connected back to the hot water storage tank (2) via a pipeline; The phase change heat collection plate (5) in the phase change heat collection device comprises a heat absorption plate (501), a binder (502), a solid phase change layer (503), a fluid channel (504) and a heat insulation layer (505) in sequence; the heat storage tank (2) is connected to the inlet end of the fluid channel (504) through a heat collection regulating valve (802) and a heat collection circulation pump (702) in sequence, and the outlet end of the fluid channel (504) is connected back to the heat storage tank (2) through a pipeline; The electric heating water tank (3) in the geothermal device is connected to one end of the geothermal pipe (6) via a geothermal circulation pump (703) and a geothermal front valve (803) in sequence, and the other end of the geothermal pipe (6) is connected back to the electric heating water tank (3) through a pipeline via a geothermal rear valve (805); The drip irrigation water tank (4) in the drip irrigation device is connected to the geothermal pipe (6) via a drip irrigation circulation pump (704) and a drip irrigation regulating valve (804) in sequence; the drip irrigation outlet (601) of the geothermal pipe (6) is connected to the drip irrigation inlet (901); an electromagnetic shutoff valve (902) and a drip irrigation port (903) are provided on the pipeline connected to the drip irrigation inlet (901); and a spray port (904) is provided at the end of the pipeline; A heat conduction plate (201) is provided between the water storage tank (2) and the electric heating tank (3).

2. A greenhouse heat storage and insulation system based on photovoltaic thermal energy according to claim 1, characterized in that: The photovoltaic thermal assembly (1) is electrically connected to an electric heating water tank (3), a photovoltaic circulation pump (701), a heat collection circulation pump (702), a geothermal circulation pump (703), a drip irrigation circulation pump (704), a roller shutter machine (10), a lighting lamp, and a storage battery.

3. A greenhouse heat storage and insulation system based on photovoltaic thermal energy according to claim 2, characterized in that: The outer layers of the water storage tank (2) and the electric heating tank (3) are provided with aerogel thermal insulation material.

4. A working method of a greenhouse heat storage and insulation system based on photovoltaic thermal energy according to any one of claims 1 to 3, characterized in that: a. The photovoltaic thermal component (1) is connected to a water storage tank (2), and the paraffin solution / graphene oxide phase change fluid therein exchanges heat when flowing through the photovoltaic thermal component (1), and the heat removed is stored in the water storage tank (2); b. The phase change heat collecting plate (5) is connected to the hot water storage tank (2); the heat absorbing layer (501) in the phase change heat collecting plate (2) absorbs heat from solar radiation and is stored in the solid phase change layer (503); When the paraffin solution / graphene oxide phase change fluid in the hot water storage tank (2) flows through the fluid channel (504), heat exchange is performed, and the heat is taken away and stored in the hot water storage tank (2); c. The water storage tank (2) exchanges heat with the water in the electric heating water tank (3) through the heat conduction plate (201), thereby preliminarily heating the water in the electric heating water tank (3); d. The electric heating water tank (3) is connected to the geothermal pipe (6). The temperature control system in the electric heating water tank (3) automatically heats the water preheated by the heat storage tank (2) to the required water temperature according to the temperature requirements in the greenhouse. e. The water in the electric heating water tank (3) is transported to the geothermal pipe (6) through a water pump, and the heat is transferred to the vegetation layer through the geothermal pipe (6); f. The drip irrigation water tank (4), the geothermal pipe (6), and the drip irrigation device are connected, the electromagnetic shutoff valve (902) of the drip irrigation device is opened, and the opening of the drip irrigation port (903) is adjusted, so that the water in the drip irrigation water tank (4) passes through the geothermal pipe (6) and the drip irrigation device to drip irrigate the vegetation; g. When the temperature in the greenhouse is too high, rotate and open the spray port (904) to perform direct evaporative cooling.

5. The working mode of a greenhouse heat storage and insulation system based on photovoltaic thermal energy according to any one of claims 1 to 3, characterized in that: i) Daytime operation mode in clear weather: The photovoltaic regulating valve (801) and the heat collecting regulating valve (802) are opened, and the geothermal front valve (803), the geothermal rear valve (805) and the drip irrigation regulating valve (804) are closed. The phase change fluid at 20 to 25° C. in the photovoltaic thermal assembly (1) and the phase change collector plate (5) is heated to 35 to 40° C. after being irradiated by sunlight. The heated phase change fluid is transported to the hot water storage tank (2) for storage via the photovoltaic circulation pump (701) and the heat collecting circulation pump (702); ii) Night operation mode where temperature requirements are not high: The heat collection regulating valve (802) and the heat collection water pump (702) are opened, and the photovoltaic regulating valve (801), the geothermal front valve (803), the geothermal rear valve (805) and the drip irrigation regulating valve (804) are closed. The 30-35°C low-temperature phase change fluid in the heat storage tank (2) transfers heat to the phase change heat collection plate (5), and the phase change heat collection plate (5) transfers the heat to the greenhouse through convection heat exchange; iii) Operation mode with low temperature and insufficient sunlight: The geothermal front valve (803) and the geothermal rear valve (805) are opened, and the photovoltaic regulating valve (801), the heat collecting regulating valve (802) and the drip irrigation regulating valve (804) are closed. The water in the electric heating water tank (3) absorbs the heat in the heat storage tank (2) and becomes low-temperature hot water of 30°C±5°C. The water is further electrically heated to a set temperature. The geothermal circulation valve (703) transports the heated water to the geothermal pipe (6), and the heat is dissipated to the vegetation layer through the geothermal pipe (6); iv) Nighttime operation mode when the temperature is low and the daytime sunlight is sufficient: The heat collecting regulating valve (802), the geothermal front valve (803), and the geothermal rear valve (805) are opened, and the photovoltaic regulating valve (801) and the drip irrigation regulating valve (804) are closed, and the heat in the hot water storage tank (2) and the electric heating water tank (3) is transferred to the greenhouse through the phase change heat collecting plate (5) and the geothermal pipe (6) respectively; v) Drip irrigation mode: The drip irrigation regulating valve (804) is opened, the geothermal front valve (803) and the geothermal rear valve (805) are closed, the electromagnetic shut-off valve (902) of the drip irrigation device is opened, the opening of the drip irrigation port (903) is adjusted, and the water in the drip irrigation water tank (4) is drip-irrigated to the vegetation through the geothermal pipe (6) and the drip irrigation device; when the temperature in the greenhouse is too high, the spray port (904) of the drip irrigation device is rotated to open and direct evaporative cooling is performed.

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