A dynamic and static combined photovoltaic greenhouse combined cooling and heating system and method

Abstract

The application discloses a dynamic and static combined photovoltaic greenhouse combined cooling and heating system and method, and belongs to the technical field of solar energy utilization, which comprises a photovoltaic power generation system, a combined cooling and heating system composed of a variable frequency compressor, a plate heat exchanger, a condenser, a throttling valve, an evaporator, a four-way reversing valve and a heat exchange water pump, a storage and use system composed of a hot water tank, a cold water tank, a water pump, a fan and a greenhouse, and the plate heat exchanger and the hot water tank form a heat medium water circulation pipeline to store heat; the evaporator is located in the cold water tank immersed in water; the cold water tank and the greenhouse form a cooling water circulation pipeline to reduce temperature; and the hot water tank and the greenhouse form a heat medium water circulation pipeline to supply heat. The application directly drives the dynamic and static combined combined cooling and heating system by using solar energy, realizes the double-effect function of combined cooling and heating, simultaneously realizes the double function of static heating and dynamic heating, can avoid the disadvantages that the greenhouse is easily affected by the environment, and provides a stable and controllable environment for the growth of cultivated crops.

Description

Technical Field

[0001] This invention relates to the field of solar greenhouse technology, and more specifically to a photovoltaic greenhouse combined cooling and heating system and method that combines dynamic and static technologies. Background Technology

[0002] With the development of modern agriculture, greenhouse systems have experienced rapid growth due to their relatively low susceptibility to environmental impact and their ability to provide a stable and controllable environment for crop growth. From an environmental perspective, the best way to address the energy and environmental issues caused by greenhouse systems is to utilize photovoltaic energy to power their operation. However, due to the intermittent nature of solar irradiance, thermal energy storage technologies—which utilize the sensible or latent heat of substances to store the cooling or heating energy generated by solar energy—have become a key focus for future solar energy utilization development. Compared to traditional grid-driven thermal energy storage or heating systems, novel and environmentally friendly photovoltaic cooling / heating technologies hold even greater significance.

[0003] Through research and operational data analysis of photovoltaic greenhouse cooling and heating technologies, the main problems existing in the cooling and heating systems of current photovoltaic greenhouses have been identified, as follows:

[0004] (1) Ventilation is the most common cooling method for photovoltaic greenhouses, but it also wastes the heat energy contained in the air inside the greenhouse.

[0005] (2) Under the experimental conditions, the heat pump was used to capture the residual heat energy of the greenhouse air and use it for heating at night. The average energy saving rate and economic feasibility of the system were both low.

[0006] (3) Existing combined cooling and heating systems can only provide heating or cooling on their own, and cannot achieve the recovery of waste heat in the greenhouse while providing cooling.

[0007] Therefore, how to efficiently and fully utilize solar energy resources and greenhouse waste heat, while simultaneously achieving the dual functions of ice-making and cooling storage, and heating storage, reducing the capacity of power distribution, cooling and heating units, improving the efficiency of waste heat utilization in greenhouses, and reducing operating costs are problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a photovoltaic greenhouse combined cooling and heating system and method that combines dynamic and static technologies, achieving efficient and stable operation of ice making and cold storage and heating, while realizing static and dynamic heating, improving the utilization efficiency of greenhouse waste heat, increasing the comprehensive utilization rate of solar energy, and reducing costs.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] On the one hand, the present invention provides a photovoltaic greenhouse combined cooling and heating system that combines dynamic and static elements, including: a photovoltaic power generation system, a combined cooling and heating system, and an energy storage system;

[0011] The photovoltaic power generation system is used to convert solar energy into electrical energy and supply it to the combined cooling and heating system;

[0012] The combined cooling and heating system is used to achieve multiple operating modes using electrical energy, including a combined cooling and heating mode, a heating mode combining dynamic and static modes, a heating mode, and a cooling mode.

[0013] The energy storage system is used to control the operating mode according to the temperature of the greenhouse to complete the cooling or heating.

[0014] Preferably, the combined cooling and heating system includes a variable frequency compressor, a plate heat exchanger, a condenser, a throttling valve, an evaporator, a four-way reversing valve, a gas-liquid separator, and a heat exchange water pump; the variable frequency compressor is connected to the photovoltaic power generation system, the plate heat exchanger, and the gas-liquid separator respectively; the four-way reversing valve is connected to the plate heat exchanger, the condenser, the gas-liquid separator, and the evaporator respectively; the condenser is also connected to one end of the throttling valve, the other end of the throttling valve is connected to the evaporator, and the heat exchange water pump is connected to the plate heat exchanger;

[0015] The energy storage system includes a hot water tank, a cold water tank, a water pump, and a circulation pipeline; the hot water tank is connected to the plate heat exchanger and the heat exchange water pump respectively; the evaporator is installed in the cold water tank; the circulation pipeline is connected to and communicates with the hot water tank, the cold water tank and the greenhouse respectively, and is used to control the cooling or heating of the greenhouse.

[0016] Preferably, the circulation pipeline includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a water pump, a fan, a first valve, a second valve, a third valve, and a fourth valve;

[0017] The first pipe is connected to the hot water tank and the cold water tank on both sides respectively. The first valve is installed on one side of the cold water tank and the second valve is installed on one side of the hot water tank. The third pipe is installed between the first valve and the second valve.

[0018] The second pipe is connected to the hot water tank and the cold water tank on both sides respectively. The third valve is installed on one side of the cold water tank and the fourth valve is installed on one side of the hot water tank. The fourth pipe is installed between the third valve and the fourth valve.

[0019] The third pipe and the fourth pipe are connected to both sides of the fan, and the water pump is installed on the third pipe.

[0020] Preferably, the greenhouse is equipped with a temperature sensor to collect the temperature inside the greenhouse and feed it back to the combined cooling and heating system and the energy storage system.

[0021] Preferably, the photovoltaic power generation system includes photovoltaic modules and an inverter controller connected in sequence.

[0022] Preferably, in the combined cooling and heating mode:

[0023] The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant to pass through the plate heat exchanger, the condenser, the throttle valve, the evaporator, and the gas-liquid separator in sequence before returning to the variable frequency compressor. The condenser does not exchange heat with the air. When the first valve and the second valve are open, the cold water tank and the greenhouse form a cooling water circulation pipeline to cool the greenhouse. When the third valve and the fourth valve are open, the hot water tank and the greenhouse form a heat transfer medium circulation pipeline.

[0024] Preferably, in the combined dynamic and static heating mode:

[0025] The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger and the hot water tank form a heat transfer medium circulation loop. The condenser exchanges heat with the air. The first valve, the second valve, the third valve, and the fourth valve are all open, and the hot water tank and the cold water tank both form a heat transfer medium circulation loop with the greenhouse.

[0026] Preferably, in the cooling mode:

[0027] The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the condenser, the throttle valve, the evaporator, and the gas-liquid separator back to the variable frequency compressor. The condenser exchanges heat with the air. The evaporator directly contacts the water in the cold water tank to cool the water. The first valve and the second valve are opened, and the cold water tank and the greenhouse form a cooling water circulation pipeline.

[0028] Preferably, in the heating mode:

[0029] The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger does not form a heat transfer fluid circulation loop with the hot water tank. The evaporator directly contacts the water in the cold water tank to heat the water. The cold water tank forms a heat transfer fluid circulation loop with the greenhouse. The condenser exchanges heat with the air. When the first valve and the second valve are opened, the cold water tank and the greenhouse form a heat transfer fluid circulation pipeline.

[0030] On the other hand, the present invention provides a method for combined cooling and heating of a photovoltaic greenhouse that combines dynamic and static methods. The method utilizes the combined cooling and heating system for a photovoltaic greenhouse described in any one of the above-mentioned claims to perform combined cooling and heating, refrigeration, and heating on the greenhouse, comprising the following steps:

[0031] Combined cooling and heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant through the plate heat exchanger, the condenser, the expansion valve, the evaporator, and the gas-liquid separator before returning to the variable frequency compressor. The condenser does not exchange heat with the air. When the greenhouse temperature is higher than the preset value, the circulation pipeline controls the cold water tank to form a cooling water circulation pipeline with the greenhouse to cool the greenhouse. When the greenhouse temperature is lower than the preset value, the circulation pipeline controls the hot water tank to form a heat transfer medium circulation pipeline with the greenhouse to heat the greenhouse.

[0032] A combined dynamic and static heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor; the four-way reversing valve connects the plate heat exchanger and the evaporator; the variable frequency compressor drives the refrigerant to sequentially pass through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator before returning to the variable frequency compressor; the plate heat exchanger and the hot water tank form a heat transfer medium circulation loop; the condenser exchanges heat with the air; when the greenhouse temperature is lower than a preset value, the circulation pipe controls both the hot water tank and the cold water tank to form a heat transfer medium circulation loop with the greenhouse to provide heating;

[0033] Cooling mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the condenser, the expansion valve, the evaporator, and the gas-liquid separator back to the variable frequency compressor. The condenser exchanges heat with the air. The evaporator directly contacts the water in the cold water tank to cool the water. When the greenhouse temperature is higher than the preset value, the circulation pipeline controls the cold water tank and the greenhouse to form a cooling water circulation pipeline to cool the greenhouse.

[0034] Heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger does not form a heat transfer water circulation loop with the hot water tank. The evaporator directly contacts the water in the cold water tank to heat the water. The cold water tank forms a heat transfer water circulation loop with the greenhouse. The condenser exchanges heat with the air. When the greenhouse temperature is lower than the preset value, the circulation pipe controls the cold water tank and the greenhouse to form a heat transfer water circulation pipeline to supply heat to the greenhouse.

[0035] As can be seen from the above technical solution, compared with the prior art, this invention discloses a photovoltaic greenhouse combined cooling and heating system and method that combines dynamic and static technologies. By optimizing and modifying the combined cooling and heating system, it can simultaneously achieve the dual functions of ice making, cold storage, heating, and heat storage. Switching via a four-way reversing valve can achieve both static and dynamic heating functions, improving the efficiency of greenhouse waste heat utilization, increasing the overall utilization rate of solar energy, and reducing costs. Furthermore, based on temperature feedback within the greenhouse, it can achieve the function of simultaneous energy storage and consumption, avoiding the drawbacks of the greenhouse's susceptibility to environmental influences and providing a stable and controllable environment for crop growth. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 This invention provides a structural diagram of a photovoltaic greenhouse combined cooling and heating system that combines dynamic and static elements. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention discloses a photovoltaic greenhouse combined cooling and heating system that combines dynamic and static technologies, such as... Figure 1 As shown, it includes: photovoltaic power generation system, combined cooling and heating system, and energy storage system;

[0040] Photovoltaic power generation systems are used to convert solar energy into electrical energy and supply it to combined cooling, heating and cooling systems.

[0041] Combined cooling and heating (CCHP) systems utilize electrical energy to achieve multiple operating modes, including CCHP mode, a combined dynamic and static heating mode, a heating mode, and a cooling mode. When there are large temperature differences between day and night, CCHP mode is activated to collect energy from the greenhouse during the day for nighttime heating. In winter, when temperatures are low and greenhouse crops require more heat, the combined dynamic and static heating mode is activated to achieve cascaded energy utilization, enhance energy storage, and improve solar energy utilization. When the greenhouse requires less heat in winter, the heating mode is activated to improve heating efficiency. In summer, when temperatures are high and the greenhouse temperature exceeds the crop's growth temperature, a larger cooling load is required; activating the cooling mode, where the evaporator is in direct contact with water, improves cooling efficiency.

[0042] The energy storage system is used to provide cooling or heating based on the greenhouse's temperature control operating mode.

[0043] The combined cooling and heating system includes a variable frequency compressor 3, a plate heat exchanger 4, a condenser 6, a throttling valve 7, an evaporator 8, a four-way reversing valve 5, a gas-liquid separator 9, and a heat exchange water pump 12. The variable frequency compressor 3 is connected to the photovoltaic power generation system, the plate heat exchanger 4, and the gas-liquid separator 9. The four-way reversing valve 5 is connected to the plate heat exchanger 4, the condenser 6, the gas-liquid separator 9, and the evaporator 7. The condenser 6 is also connected to one end of the throttling valve 7, and the other end of the throttling valve 7 is connected to the evaporator 7. The heat exchange water pump 12 is connected to the plate heat exchanger 4.

[0044] The energy storage system includes a hot water tank 11, a cold water tank 10, a water pump 13, and a circulation pipe. The hot water tank 11 is connected to the plate heat exchanger 4 and the heat exchange water pump 12. The evaporator 7 is installed in the cold water tank 10. The circulation pipe is connected to the hot water tank 11, the cold water tank 10, and the greenhouse 15, and is used to control the cooling or heating of the greenhouse 15.

[0045] To compensate for the intermittent nature of solar energy and ensure the operation of both the cooling and heating systems, the combined cooling and heating system was optimized and modified. After optimization, the evaporator 8 is placed inside the cold water tank 10, and the plate heat exchanger 4 stores hot water in the hot water tank 11 via the heat exchange pump 12. This allows for the simultaneous realization of ice-making, cold storage, and heat storage functions. A four-way reversing valve 5 allows for both static and dynamic heating. Furthermore, based on temperature feedback within the greenhouse, energy can be stored and used simultaneously, avoiding the drawbacks of the greenhouse's susceptibility to environmental influences and providing a stable and controllable environment for crop growth.

[0046] Preferably, the circulation pipeline includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a water pump 13, a fan 14, a first valve 16, a second valve 17, a third valve 18, and a fourth valve 19;

[0047] The first pipe is connected to a hot water tank 11 and a cold water tank 10 on both sides respectively. A first valve 16 is installed on one side of the cold water tank 10 and a second valve 17 is installed on one side of the hot water tank 11. The third pipe is installed between the first valve 16 and the second valve 17.

[0048] The second pipe is connected to the hot water tank 11 and the cold water tank 10 on both sides respectively. A third valve 18 is installed on one side of the cold water tank 10, and a fourth valve 19 is installed on one side of the hot water tank 11. The fourth pipe is installed between the third valve 18 and the fourth valve 19.

[0049] The third and fourth pipes are connected to both sides of the fan 14, and the water pump 13 is installed on the third pipe.

[0050] Preferably, a temperature sensor is installed inside the greenhouse 15 to collect the temperature inside the greenhouse and feed it back to the combined cooling and heating system and the energy storage system. The combined cooling and heating system adjusts its operating mode according to the temperature requirements of the crops inside the greenhouse and the real-time temperature of the greenhouse fed back by the temperature sensor. The energy storage system adjusts the switching of valves according to the operating mode of the combined cooling and heating system and the real-time temperature feedback from the temperature sensor.

[0051] Preferably, the photovoltaic power generation system includes a photovoltaic module 1 and an inverter controller 2 connected in sequence.

[0052] In the preferred combined cooling and heating mode:

[0053] The four-way reversing valve 5 connects the plate heat exchanger 4 and the condenser 6. When the irradiance reaches the system startup conditions of the variable frequency compressor 3, the variable frequency compressor 3 drives the refrigerant through the plate heat exchanger 4, condenser 6, expansion valve 7, evaporator 7, and gas-liquid separator 9 back to the variable frequency compressor 3. At this time, the evaporator 8 is in a state of simultaneous ice making and cold storage, and the condenser 6 does not exchange heat with the air. When the first valve 16 and the second valve 17 are opened, the cold water tank 10 and the greenhouse 15 form a cooling water circulation pipeline. As the solar irradiance gradually increases... The temperature inside the greenhouse will gradually rise. Pump 13 will circulate the cold water from the cold water tank 10 to the fan 14 inside the greenhouse for heat exchange with the hot air, until the solar irradiance can no longer drive the variable frequency compressor 3. At night, when there is no sun and the temperature is lower, valves 18 and 19 will open, forming a heat transfer fluid circulation pipeline between the hot water tank 11 and the greenhouse 15. Pump 13 will then transfer the heat from the hot water tank 11 to the greenhouse via the fan 14, maintaining the temperature required for the greenhouse crops until the sun comes out, at which point a new cycle begins. This combined cooling and heating system, which recovers greenhouse heat while providing cooling, reduces energy consumption and improves solar energy utilization.

[0054] In the preferred heating mode that combines dynamic and static heating:

[0055] The four-way reversing valve 5 connects the plate heat exchanger 4 and the evaporator 7. When the irradiance reaches the system start-up conditions of the variable frequency compressor 3, the variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, evaporator 7, throttle valve 7, condenser 6, and gas-liquid separator 9 in sequence back to the variable frequency compressor 3. At this time, the evaporator 8 is in a state of heating and storing heat at the same time until the solar irradiance can no longer drive the variable frequency compressor 3 to run. The plate heat exchanger 4 and the hot water tank 11 form a heat medium water circulation loop. The condenser 6 exchanges heat with the air. The first valve 16, the second valve 17, the third valve 18, and the fourth valve 19 are all opened. The hot water tank 11 and the cold water tank 10 form a heat medium water circulation loop with the greenhouse 15 to supply the greenhouse 15. At this time, when the temperature fed by the temperature sensor of the greenhouse is lower than 15°C, the water pump 13 runs to circulate the heat in the hot water tank 11 and the cold water tank 10 to the fan 14 in the greenhouse to exchange heat with the hot air in the greenhouse, so as to maintain the temperature required for the greenhouse crops until the sun comes out and a new cycle begins. Dynamic and static heating can enable the cascade utilization of energy and improve energy storage.

[0056] In the preferred cooling mode:

[0057] The four-way reversing valve 5 connects the plate heat exchanger 4 and the condenser 6. When the irradiance reaches the system start-up conditions of the variable frequency compressor 3, the variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, condenser 6, throttle valve 7, evaporator 7, and gas-liquid separator 9 in sequence and return to the variable frequency compressor 3. The condenser 6 exchanges heat with the air. The evaporator 7 directly contacts the water in the cold water tank 10 to cool the water. The first valve 16 and the second valve 17 are opened, and the cold water tank 10 and the greenhouse 15 form a cooling water circulation pipeline to cool the greenhouse 15. In the refrigeration mode, the combination of air cooling and water cooling can greatly improve the refrigeration efficiency.

[0058] In the preferred heating mode:

[0059] The four-way reversing valve 5 connects the plate heat exchanger 4 and the evaporator 7. When the irradiance reaches the starting condition of the variable frequency compressor system, the variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, the evaporator 7, the expansion valve 7, the condenser 6, and the gas-liquid separator 9 in sequence back to the variable frequency compressor 3. The plate heat exchanger 4 does not form a heat medium water circulation loop with the hot water tank 11. The evaporator 7 directly contacts the water in the cold water tank 10 to heat the water. The cold water tank 10 forms a heat medium water circulation loop with the greenhouse 15. The condenser 6 exchanges heat with the air. The first valve 16 and the second valve 17 are opened, and the cold water tank 10 and the greenhouse 15 form a heat medium water circulation pipeline to supply heat to the greenhouse 15. In the heating mode, the evaporator directly contacts the water, which can improve the heating efficiency.

[0060] On the other hand, the present invention provides a method for combined cooling and heating of a photovoltaic greenhouse that combines dynamic and static methods. The method utilizes a combined cooling and heating system for a photovoltaic greenhouse (as described in any one of the above-mentioned methods) to provide combined cooling and heating, cooling, and heating to a greenhouse 15, comprising the following steps:

[0061] Combined cooling and heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor 3. The four-way reversing valve 5 connects the plate heat exchanger 4 and the condenser 6. The variable frequency compressor 3 drives the refrigerant through the plate heat exchanger 4, condenser 6, throttle valve 7, evaporator 7 and gas-liquid separator 9 in sequence and returns to the variable frequency compressor 3. The condenser 6 does not exchange heat with the air. When the temperature of greenhouse 15 is higher than the preset value, the circulation pipeline controls the cold water tank 10 to form a cooling water circulation pipeline with greenhouse 15 to cool greenhouse 15. When the temperature of greenhouse 15 is lower than the preset value, the circulation pipeline controls the hot water tank 11 to form a heat transfer water circulation pipeline with greenhouse 15 to heat greenhouse 15.

[0062] The heating mode combines dynamic and static heating: the photovoltaic power generation system supplies power to the variable frequency compressor 3, the four-way reversing valve 5 connects the plate heat exchanger 4 and the evaporator 7, the variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, the evaporator 7, the throttle valve 7, the condenser 6, and the gas-liquid separator 9 in sequence and return to the variable frequency compressor 3; the plate heat exchanger 4 and the hot water tank 11 form a heat medium water circulation loop; the condenser 6 exchanges heat with the air; when the temperature of the greenhouse 15 is lower than the preset value, the circulation pipe controls the hot water tank 11 and the cold water tank 10 to form a heat medium water circulation loop with the greenhouse 15 to heat the greenhouse 15;

[0063] Cooling mode: The photovoltaic power generation system supplies power to the variable frequency compressor 3. The four-way reversing valve 5 connects the plate heat exchanger 4 and the condenser 6. The variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, condenser 6, throttle valve 7, evaporator 7, and gas-liquid separator 9 in sequence and return to the variable frequency compressor 3. The condenser 6 exchanges heat with the air. The evaporator 7 directly contacts the water in the cold water tank 10 to cool the water. When the temperature of the greenhouse 15 is higher than the preset value, the circulation pipeline controls the cold water tank 10 and the greenhouse 15 to form a cooling water circulation pipeline to cool the greenhouse 15.

[0064] Heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor 3. The four-way reversing valve 5 connects the plate heat exchanger 4 and the evaporator 7. The variable frequency compressor 3 drives the refrigerant to pass through the plate heat exchanger 4, the evaporator 7, the expansion valve 7, the condenser 6, and the gas-liquid separator 9 in sequence before returning to the variable frequency compressor 3. The plate heat exchanger 4 does not form a heat transfer water circulation loop with the hot water tank 11. The evaporator 7 directly contacts the water in the cold water tank 10 to heat the water. The cold water tank 10 forms a heat transfer water circulation loop with the greenhouse 15. The condenser 6 exchanges heat with the air. When the temperature of the greenhouse 15 is lower than the preset value, the circulation pipe controls the cold water tank 10 and the greenhouse 15 to form a heat transfer water circulation pipeline to heat the greenhouse 15.

[0065] In this embodiment, waste heat recovery in a greenhouse is taken as an example. As shown in Table 1, this technology is used to recover residual air heat energy in the greenhouse. When there is a large temperature difference between day and night, solar energy is used as the driving source of the greenhouse system. The recovered heat energy can meet the heating needs of greenhouse crops at night. The average COP under the combined cooling and heating mode is 4.9, the COP under the combined static and dynamic heating mode is 2.69, the COP under the heating mode can reach 2.7, and the COP under the cooling mode can reach 2.10. The solar energy utilization rate is high and the energy saving benefits are significant.

[0066] Table 1. Waste heat recovery effect of a greenhouse in a certain unit.

[0067]

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic greenhouse combined cooling and heating system that combines dynamic and static technologies, characterized in that, include: Photovoltaic power generation systems, combined cooling and heating systems, and energy storage systems; The photovoltaic power generation system is used to convert solar energy into electrical energy and supply it to the combined cooling and heating system; The combined cooling and heating system is used to achieve multiple operating modes using electrical energy, including a combined cooling and heating mode, a heating mode combining dynamic and static modes, a heating mode, and a cooling mode. The energy storage system is used to control the working mode according to the temperature of the greenhouse to complete the cooling or heating supply; The combined cooling and heating system includes a variable frequency compressor, a plate heat exchanger, a condenser, a throttling valve, an evaporator, a four-way reversing valve, a gas-liquid separator, and a heat exchange water pump. The variable frequency compressor is connected to the photovoltaic power generation system, the plate heat exchanger, and the gas-liquid separator. The four-way reversing valve is connected to the plate heat exchanger, the condenser, the gas-liquid separator, and the evaporator. The condenser is also connected to one end of the throttling valve, and the other end of the throttling valve is connected to the evaporator. The heat exchange water pump is connected to the plate heat exchanger. The energy storage system includes a hot water tank, a cold water tank, a water pump, and a circulation pipeline; the hot water tank is connected to the plate heat exchanger and the heat exchange water pump respectively; the evaporator is installed in the cold water tank; the circulation pipeline is connected to and communicates with the hot water tank, the cold water tank and the greenhouse respectively, and is used to control the cooling or heating of the greenhouse; The circulation pipeline includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a water pump, a fan, a first valve, a second valve, a third valve, and a fourth valve; The first pipe is connected to the hot water tank and the cold water tank on both sides respectively. The first valve is installed on one side of the cold water tank and the second valve is installed on one side of the hot water tank. The third pipe is installed between the first valve and the second valve. The second pipe is connected to the hot water tank and the cold water tank on both sides respectively. The third valve is installed on one side of the cold water tank and the fourth valve is installed on one side of the hot water tank. The fourth pipe is installed between the third valve and the fourth valve. The third pipe and the fourth pipe are connected to both sides of the fan, and the water pump is installed on the third pipe; In the combined cooling and heating mode: The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant through the plate heat exchanger, the condenser, the expansion valve, the evaporator, and the gas-liquid separator before returning to the variable frequency compressor. The condenser does not exchange heat with the air. When the first and second valves are open, the cold water tank and the greenhouse form a cooling water circulation pipeline to cool the greenhouse. When the third and fourth valves are open, the hot water tank and the greenhouse form a heat transfer medium circulation pipeline. In the combined dynamic and static heating mode: The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger and the hot water tank form a heat transfer medium circulation loop. The condenser exchanges heat with the air. The first valve, the second valve, the third valve, and the fourth valve are all open, and the hot water tank and the cold water tank both form a heat transfer medium circulation loop with the greenhouse. In the cooling mode: The four-way reversing valve connects the plate heat exchanger and the condenser, and the variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the condenser, the throttle valve, the evaporator, and the gas-liquid separator back to the variable frequency compressor; The condenser exchanges heat with the air; The evaporator directly contacts the water in the cold water tank to cool the water; when the first valve and the second valve are opened, the cold water tank and the greenhouse form a cooling water circulation pipeline; In the heating mode: The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger does not form a heat transfer fluid circulation loop with the hot water tank. The evaporator directly contacts the water in the cold water tank to heat the water. The cold water tank forms a heat transfer fluid circulation loop with the greenhouse. The condenser exchanges heat with the air. When the first valve and the second valve are opened, the cold water tank and the greenhouse form a heat transfer fluid circulation pipeline.

2. The photovoltaic greenhouse combined cooling and heating system according to claim 1, characterized in that, The greenhouse is equipped with a temperature sensor to collect the temperature inside the greenhouse and feed it back to the combined cooling and heating system and the energy storage system.

3. The photovoltaic greenhouse combined cooling and heating system combining dynamic and static elements according to claim 1, characterized in that, The photovoltaic power generation system includes photovoltaic modules and an inverter controller connected in sequence.

4. A method for combined cooling and heating in a photovoltaic greenhouse that combines dynamic and static methods, characterized in that, The steps of using a photovoltaic greenhouse combined cooling and heating system that combines dynamic and static power supply according to any one of claims 1 to 3 to provide combined cooling and heating, cooling and heating for a greenhouse include: Combined cooling and heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant through the plate heat exchanger, the condenser, the expansion valve, the evaporator, and the gas-liquid separator before returning to the variable frequency compressor. The condenser does not exchange heat with the air. When the greenhouse temperature is higher than the preset value, the circulation pipeline controls the cold water tank to form a cooling water circulation pipeline with the greenhouse to cool the greenhouse. When the greenhouse temperature is lower than the preset value, the circulation pipeline controls the hot water tank to form a heat transfer medium circulation pipeline with the greenhouse to heat the greenhouse. A combined dynamic and static heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor; the four-way reversing valve connects the plate heat exchanger and the evaporator; the variable frequency compressor drives the refrigerant to sequentially pass through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator before returning to the variable frequency compressor; the plate heat exchanger and the hot water tank form a heat transfer medium circulation loop; the condenser exchanges heat with the air; when the greenhouse temperature is lower than a preset value, the circulation pipe controls both the hot water tank and the cold water tank to form a heat transfer medium circulation loop with the greenhouse to provide heating; Cooling mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the condenser. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the condenser, the expansion valve, the evaporator, and the gas-liquid separator back to the variable frequency compressor. The condenser exchanges heat with the air. The evaporator directly contacts the water in the cold water tank to cool the water. When the greenhouse temperature is higher than the preset value, the circulation pipeline controls the cold water tank and the greenhouse to form a cooling water circulation pipeline to cool the greenhouse. Heating mode: The photovoltaic power generation system supplies power to the variable frequency compressor. The four-way reversing valve connects the plate heat exchanger and the evaporator. The variable frequency compressor drives the refrigerant to pass sequentially through the plate heat exchanger, the evaporator, the expansion valve, the condenser, and the gas-liquid separator back to the variable frequency compressor. The plate heat exchanger does not form a heat transfer water circulation loop with the hot water tank. The evaporator directly contacts the water in the cold water tank to heat the water. The cold water tank forms a heat transfer water circulation loop with the greenhouse. The condenser exchanges heat with the air. When the greenhouse temperature is lower than the preset value, the circulation pipe controls the cold water tank and the greenhouse to form a heat transfer water circulation pipeline to supply heat to the greenhouse.

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