Water Circulation Temperature Control Buffer System and Control Method for Solar Greenhouse

Abstract

This invention relates to the field of greenhouse planting technology, providing a water circulation temperature control buffer system and control method for a solar greenhouse. The system includes an underground water storage tank, a main greenhouse structure, a water circulation component, and a control module. The water circulation component includes a circulation pump, a heat pump unit, and a temperature control unit. The circulation pump is located between the water storage tank and the water storage tank, forming a fluid loop. The heat pump unit is connected to the water storage tank via a circulation pipeline. The inlet of the temperature control unit is connected to the water storage tank, and the return end is connected to the water storage tank. The temperature control unit includes a heat dissipation module and a heat absorption module connected in parallel. The heat dissipation module cools the circulating water in the system, while the heat absorption module cools the interior of the main greenhouse structure. The water storage tank is higher than the temperature control unit. This invention utilizes the elevation difference to create a pressure difference to promote water circulation and achieves low-energy cooling through the heat absorption module, solving the problems of low thermal efficiency and high operating costs associated with other water circulation temperature control methods. The entire system has a simple structure, low cost, and is easy to manufacture and use.

Description

Technical Field

[0001] This invention relates to the field of greenhouse planting technology, and in particular to a water circulation temperature control buffer system and control method for a solar greenhouse. Background Technology

[0002] A solar greenhouse is a simplified facility structure characterized by low cost and low energy consumption. It primarily consists of three insulated and heat-storing walls and a roof that allows light to pass through, often covered with insulation. It offers good heat preservation and storage capacity in winter, with low heating energy consumption and low management costs. However, due to its relatively small overall space, excessively high temperatures inside the greenhouse during summer (30-80℃, or even higher) are detrimental to vegetable growth and development, reducing facility utilization and vegetable production capacity. Furthermore, even in winter, the temperature is susceptible to external climatic factors, resulting in poor internal environmental stability and adversely affecting vegetable production.

[0003] Therefore, inventing a low-energy, low-cost, and easy-to-maintain temperature control system has always been a hot topic in industry research and production applications. Exploring low-carbon and low-energy insulation and energy-saving methods to improve the environmental control capabilities of solar greenhouses has become an urgent task. Summary of the Invention

[0004] This invention provides a water circulation temperature control buffer system and control method for solar greenhouses, which solves the defects of poor internal environmental stability and high actual use and maintenance costs in the prior art.

[0005] The first aspect of this invention provides a water circulation temperature control buffer system for a solar greenhouse, comprising: a main greenhouse structure, a water circulation component, and a control module; a water storage tank is pre-installed underground within the main greenhouse structure; the water circulation component includes a water storage tank, a circulation pump, a heat pump unit, and a temperature control unit; the circulation pump is located on a water supply pipeline between the water storage tank and the water storage tank, and the water storage tank forms a fluid loop with the water storage tank through the water supply pipeline; the heat pump unit is connected to the water storage tank through a pipeline to form a water circulation emergency heating system; the water inlet of the temperature control unit is connected to the water storage tank through a distribution pipeline, and the water return end of the temperature control unit... The control module is connected to the water storage tank via a collection pipeline; the control module includes a temperature acquisition module for sensing indoor temperature; wherein, the temperature control unit includes a heat absorption module and a heat dissipation module arranged in parallel, the heat dissipation module is located outside the main structure of the greenhouse to cool the circulating water in the system, and the heat absorption module is located inside the main structure of the greenhouse to cool or heat the internal space of the main structure of the greenhouse and the soil; the bottom elevation of the water storage tank is higher than that of the temperature control unit, and the water storage tank is equipped with a liquid level sensor; the control module is configured to control the operation of the circulation pump and the heat pump unit based on temperature information and liquid level information.

[0006] According to the solar greenhouse water circulation temperature control buffer system provided by the present invention, the heat dissipation module includes multiple outdoor radiators arranged in series. The water inlet of the outdoor radiator is connected to the water storage tank through the distribution pipeline, and the water return of the outdoor radiator is connected to the heat absorption module and the water storage tank in sequence through the collection pipeline.

[0007] According to the solar greenhouse water circulation temperature control buffer system provided by the present invention, a booster water circuit is provided in parallel on the water connection between the outdoor radiator and the water storage tank, and a booster pump is provided on the booster water circuit. The booster pump is electrically connected to the control module.

[0008] According to the solar greenhouse water circulation temperature control and buffering system provided by the present invention, the heat absorption module includes a plurality of indoor heat exchangers and a plurality of hot water storage bags; wherein, a plurality of the indoor heat exchangers are connected in series, and at least one hot water storage bag is connected in series with the indoor heat exchangers, and at least one hot water storage bag is connected in parallel with the indoor heat exchangers. In the solar greenhouse water circulation temperature control and buffering system provided by the present invention, the plurality of indoor heat exchangers connected in series are located on one side along the length direction within the main structure of the greenhouse, and a plurality of hot water storage bags connected in series are provided on the opposite side from the indoor heat exchangers.

[0009] According to the solar greenhouse water circulation temperature control buffer system provided by the present invention, a first regulating valve is provided on the inlet connecting pipe of the first hot water storage bag in a plurality of series-connected hot water storage bags, and a second regulating valve is provided on the outlet connecting pipe of the last hot water storage bag. The first regulating valve and the second regulating valve are used to regulate the flow rate of the circulating water path.

[0010] According to the solar greenhouse water circulation temperature control buffer system provided by the present invention, the remaining portion of the hot water storage bags are located in the inter-row positions of the cultivated crops within the main structure of the greenhouse, so as to form a soil with hot water storage bags.

[0011] According to the solar greenhouse water circulation temperature control buffer system provided by the present invention, the main body of the hot water storage bag is a polyvinyl chloride hot water storage bag.

[0012] A second aspect of the present invention provides a control method for controlling the water circulation temperature control buffer system of any of the above-described solar greenhouses, comprising the following steps: Based on the selection of control modes according to the ambient temperature inside the greenhouse; Based on the selected control mode, and in conjunction with temperature and liquid level information, control at least one action of the circulating pump and / or booster pump, or control at most one action of the heat pump unit and / or circulating pump.

[0013] According to the control method provided by the present invention, controlling one or both of the circulating pump, booster pump, and heat pump unit to operate simultaneously based on the selected control mode specifically includes the following steps: When the liquid level is lower than the preset liquid level threshold, the circulation pump is turned on to transport the water in the water storage tank to the water storage tank. When t1≤greenhouse ambient temperature≤t2, and the temperature information is higher than the preset first temperature threshold, control the booster pump to run; When t3≤the ambient temperature inside the greenhouse≤t4, and the temperature information is lower than the preset second temperature threshold, the heat pump unit is controlled to operate; Among them, t4 <t1。

[0014] This invention provides a water circulation temperature control buffer system and control method for solar greenhouses. It utilizes the pressure potential energy generated by elevation differences to promote water circulation. A heat-absorbing module installed within the main greenhouse structure achieves low-energy cooling, solving the problems of low thermal efficiency and high operating costs associated with other water circulation temperature control methods. Water circulation systems typically involve heat exchange processes, with water circulating as the cooling medium. In summer, the heat-absorbing module absorbs heat from inside the greenhouse and dissipates it through the water circulation components to the heat dissipation module outside the greenhouse, thus achieving low-energy cooling. In winter, the external circulation is closed, and the heat-absorbing module absorbs excess heat from inside the greenhouse during the day and stores it in the water, lowering the daytime temperature. At night, the heat is released back into the greenhouse, increasing the nighttime temperature. In extreme temperatures and prolonged cloudy days, when the outside temperature is high during the day, a heat pump unit can acquire external energy to increase the heat capacity of the circulating water. This internal circulation then heats the greenhouse, effectively smoothing out temperature peaks and valleys and buffering the greenhouse's temperature control capabilities, thus creating a continuous cycle. The entire circulation system has a simple structure, is easy to manufacture, and has low preparation and operating costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is one of the schematic diagrams of the overall layout structure of the solar greenhouse water circulation temperature control buffer system provided by the present invention.

[0017] Figure 2 This is the second schematic diagram of the overall layout structure of the solar greenhouse water circulation temperature control buffer system provided by the present invention.

[0018] Figure 3 This is a flowchart illustrating the control method of the water circulation temperature control buffer system for solar greenhouses provided by the present invention.

[0019] Figure label: 10. Greenhouse main structure; 11. Water storage tank; 111. Float valve; 20. Water circulation assembly; 21. Water storage tank; 22. Circulation pump; 23. Heat dissipation module; 231. Outdoor radiator; 24. Heat absorption module; 241. Indoor heat exchanger; 242. Hot water storage bag; 243. First control valve; 244. Second control valve; 25. Heat pump unit; 26. Booster pump; 30. Control module. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of clarifying the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0023] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] In related research in this field, high summer temperatures increase plant respiration rates, affecting carbohydrate accumulation, causing seedling elongation, flower and fruit drop, and reducing both biological and economic yields of vegetables. High temperatures in greenhouses during summer have many adverse effects on cherry tomato growth, such as leaf scorching, reduced photosynthesis, and increased risk of disease. The suitable temperature range for tomato growth in a solar greenhouse is typically between 20℃ and 30℃, with the optimal temperature around 22℃ to 25℃. During the fruiting period, the suitable daytime temperature is 22℃ to 28℃, and the nighttime temperature is 12℃ to 17℃. Therefore, regulating the high-temperature environment in summer is crucial for achieving year-round production of greenhouse crops. Winter temperatures are unstable due to external climatic factors, often resulting in temperatures below the optimal growth and development temperature for vegetables, leading to highly unstable indoor temperatures and negatively impacting vegetable production.

[0026] Among the related technologies, typical solutions include solar water circulation systems and water circulation substrate cooling systems. These systems all require complex layouts and precise control, which leads to high overall layout costs, high energy consumption, and difficult maintenance and operating costs.

[0027] To address the problems in related technologies, this invention provides a water circulation temperature control buffer system for a solar greenhouse, comprising a main greenhouse structure 10, a water circulation component 20, and a control module 30; a water storage tank 11 is pre-installed underground within the main greenhouse structure 10; the water circulation component 20 includes a water storage tank 21, a circulation pump 22, a heat pump unit 25, and a temperature control unit; the circulation pump 22 is located on a water supply pipeline between the water storage tank 21 and the water storage tank 11, and the water storage tank 21 forms a fluid loop with the water storage tank 11 through the water supply pipeline; the heat pump unit 25 is connected to the water storage tank 21 through a circulation pipeline to form a water circulation heating system; the temperature control unit has a water inlet end... The temperature control unit is connected to the water storage tank 21 via a distribution pipeline, and the return water end is connected to the heat absorption module 24 and the water storage tank 11 in sequence via a collection pipeline. The control module 30 includes a temperature acquisition module for sensing the indoor temperature. The temperature control unit includes a heat absorption module 24 and a heat dissipation module 23 arranged in parallel. The heat dissipation module 23 is located outside the main structure 10 of the greenhouse, and the heat absorption module 24 is located inside the main structure 10 of the greenhouse. The bottom surface of the water storage tank 21 is higher than that of the temperature control unit, and a liquid level sensor is provided inside the water storage tank 21. The control module 30 is configured to control the operation of the circulation pump 22 and the heat pump unit 25 based on the temperature information and the liquid level information. Crops in a solar greenhouse require a stable temperature environment for optimal growth. In summer, prolonged sunlight can cause excessively high temperatures inside the greenhouse, necessitating cooling. Conversely, in winter, lower external temperatures can lead to excessively low temperatures inside the greenhouse, requiring heating. This embodiment addresses this by utilizing a high-positioned water tank 21, with the height difference between the tank and the temperature control unit enabling self-circulation of circulating water. A heat dissipation module 23 cools the circulating water, while a heat absorption module 24 absorbs heat from the greenhouse interior, thus controlling the temperature. Conversely, when heating is needed, a heat pump unit 25 heats the circulating water, dissipating the heat during circulation to regulate the greenhouse temperature.

[0028] The main greenhouse structure 10 includes a frame structure, a roof structure, and wall structures. The frame structure serves as the main supporting structure, while the roof and wall structures are connected to it, forming an internal space for crop cultivation. A pre-installed water storage tank 11 stores circulating water. Alternatively, a water tank can be installed within the water storage tank 11, storing circulating water to achieve water circulation and regulate the internal temperature of the greenhouse structure 10 during this circulation process.

[0029] Specifically, both the circulating pump 22 and the heat pump unit 25 are electrically connected to the control module 30. The control module 30 can execute corresponding control decisions based on the control model stored internally in the controller, thereby realizing the control of the equipment. For example, after receiving liquid level information, the control module 30 can control the circulating water pump to perform water filling operations based on feedback, transporting water from the water storage tank 11 to the water storage tank 21. After receiving temperature information and receiving feedback that the temperature exceeds the threshold, the circulating water needs to be rapidly cooled. At this time, the circulating water can be quickly cooled through the outdoor radiator 231.

[0030] During the circulation process, because the water storage tank 21 is positioned higher than other components, a height difference is created, enabling automatic flow of the circulating water and heat exchange during this flow. Specifically, in scenarios where indoor high temperatures require cooling, the circulating water is forced to flow due to the height difference. A portion of the circulating water exchanges heat with the indoor temperature through the heat absorption module 24, achieving heat exchange for the high indoor temperature. The other portion of the circulating water is cooled through the heat dissipation module 23, resulting in a circulating water temperature lower than the indoor ambient temperature. This allows the circulating water to quickly cool the internal environment of the greenhouse main structure 10 as it flows within the heat absorption module 24.

[0031] In a specific configuration, the heat dissipation module 23 can cool the circulating water by exchanging heat with other refrigerants or other low-temperature environments, thereby achieving the purpose of lowering the circulating water temperature. The heat absorption module 24 can also be a heat exchanger or other heat exchange device, enabling the water to carry away heat from the interior space of the greenhouse body during its flow.

[0032] Understandably, compared to the complex control schemes and high energy consumption of related technologies, this embodiment, by placing the water storage tank 21 at a high position, ensures that the water level in the tank is higher than that of the heat absorption module 24 and the heat dissipation module 23. This allows the water to flow through its own elevation difference, reducing operating costs. Furthermore, the circulation pump 22 operates intermittently; that is, when the water level in the storage tank 21 is too low, the circulation pump 22 is activated to add water, and after adding water, the circulation pump 22 is turned off. This avoids the energy consumption associated with continuous water addition, reducing the overall system's energy consumption. The use of the water storage tank 21 also ensures stable circulating water flow, improving the overall system's cooling stability. In winter, by closing the external circulation path formed by the external heat dissipation module 23, the heat absorption module can absorb excess heat from the greenhouse during the day and store it in the water, lowering the high daytime temperature inside the greenhouse. At night, this heat is released back into the greenhouse, raising the nighttime temperature. In extreme temperatures and continuous cloudy days, when the outside temperature is high during the day, the heat pump unit can obtain external energy to increase the heat capacity of the circulating water body and heat the greenhouse through internal circulation, which plays a role in "peak shaving and valley filling" of greenhouse temperature and buffers the greenhouse temperature regulation capacity.

[0033] In conjunction with the above embodiments, the heat dissipation module 23 includes multiple outdoor radiators 231 arranged in series. The water inlet of the outdoor radiator 231 is connected to the water storage tank 21 through a distribution pipe, and the water return of the outdoor radiator 231 is connected to the water storage tank 11 through a collection pipe. In summer, the ambient temperature inside the main greenhouse structure 10 is often high, which requires heat dissipation. In this embodiment, the outdoor radiators 231 are used to allow the circulating water that absorbs heat from the inside of the main greenhouse structure 10 to dissipate heat to the outside through the radiators, thereby reducing the temperature of the circulating water, increasing its heat absorption capacity, and achieving rapid heat dissipation from the inside of the main greenhouse structure.

[0034] Specifically, the water inlet of the heat dissipation unit is connected to the water storage tank 21 through a pipe, and the water return end of the radiator is connected to the water storage tank 11 through a pipe, thereby forming a heat dissipation loop to achieve continuous heat dissipation of the circulating water.

[0035] In the specific setup, a control valve is installed on the pipe connecting the inlet end of the outdoor radiator 231 to the distribution pipe, and a control valve is also installed on the pipe connecting the return end of the outdoor radiator 231 to the collection pipe. The control valve can control the flow rate of the incoming and outgoing circulating water, thereby adjusting the overall flow rate of the circulating water circuit as needed, and achieving the purpose of controlling the water temperature.

[0036] Understandably, in summer, outdoor temperatures are often lower than indoor temperatures, while indoor temperatures are typically 10°C-20°C higher. Excessively high indoor temperatures can negatively impact crop growth. In this embodiment, to address the water cooling issue during water circulation, an outdoor radiator 231 is installed externally. This allows the radiator unit to exchange heat with the external environment, thereby reducing the water temperature. The entire cooling process is highly efficient and does not generate additional energy consumption.

[0037] In a specific embodiment, the main structure of the circulating pump 22 is located inside the water storage tank 11. The water storage tank 11 is 2.2m long and 1.3m in diameter, and the distance between the water storage tank 11 and the ground is 50-100cm. This allows the water in the water storage tank 21 to have a sufficient height difference to generate a pressure difference, thereby allowing the water to flow under the action of the high pressure difference. Preferably, the power of the circulating pump 22 is 0.88kW, and the water flow rate is 10m³ / h. 3 ·h -1 The maximum head is 25m. Of course, it can be adjusted according to the actual size of the greenhouse space and the degree of water volume regulation. The circulation pump 22 automatically starts and stops based on the threshold set by the water level sensors of the high-level water storage tank 21 and the underground water storage tank 11. When the water level of the high-level water storage tank 21 is lower than the set value, the circulation pump 22 is started to pump the water in the underground water storage tank 11 into the high-level water storage tank 21, forming a high pressure difference and driving the water to circulate by gravity.

[0038] In practical applications, a return port is provided on one side of the water storage tank 11. The return port is connected to the collection pipeline, so that the return water flows back through the return port. A float valve 111 is installed at the return port position to control the inflow state of the return water path.

[0039] Furthermore, the elevated water storage tank 21 can be a 2m*1.6m*1.35m plastic tank or a tank of other materials, with a volume of approximately 4000L. Of course, the capacity can be expanded or the number of water storage tanks 21 can be increased depending on the specific site size and requirements. In the specific installation, including the support frame, the water storage tank 21 is placed on the support frame, ensuring that the distance between the water storage tank 21 and the ground is greater than 2m. This provides sufficient height for the water storage tank 21, allowing for smoother flow of circulating water.

[0040] In conjunction with the above embodiments, a booster water circuit is connected in parallel to the water supply line between the outdoor radiator 231 and the water storage tank 21. A booster pump 26 is installed on the booster water circuit and is electrically connected to the control module 30. The water flow velocity within the outdoor radiator 231 affects the cooling capacity of the entire system. This embodiment uses a booster water circuit to increase the water flow velocity inside the outdoor radiator 231, thereby improving water flow efficiency, heat exchange efficiency, and achieving rapid cooling of the water, thus rapidly dissipating heat from the greenhouse main structure 10.

[0041] Specifically, such as Figure 1 As shown, with reference to the water flow direction, the inlet end of the outdoor radiator 231 at the first end is connected to the water storage tank 21 via a connecting pipe. A booster water circuit is connected in parallel to the connecting pipe at the first end. Both the booster water circuit and the connecting pipe are equipped with control valves to control the opening of their respective flow paths, thereby controlling the water flow. The outdoor radiators 231 in the middle section are connected end to end to form a series structure, and the connecting pipe at the return end of the outdoor radiator 231 at the last end is also equipped with a control valve, which can control the flow rate of the outflowing water.

[0042] It is understandable that when the temperature inside the main greenhouse structure 10 exceeds the threshold, rapid cooling is required. This requires increasing the flow rate of the water and reducing the temperature of the circulating water. In this embodiment, a pressure booster valve is installed on the flow path of the outdoor radiator 231 so that it can be opened in time when needed to provide a faster water flow rate and achieve rapid heat dissipation of the solid, thereby reducing the water temperature and improving the rapid heat dissipation of the heat inside the main greenhouse structure.

[0043] In a specific implementation, the outdoor heat exchanger is a finned tube radiator, with a size of 2m × 1m, and 9 tubes per group. The number can be adjusted according to actual needs and site space. The finned radiators can use the same specifications as the heat exchanger, fixed to the outside of the north wall of the greenhouse, and connected to the PPR pipeline to form a closed loop. The booster pump 26 has a power of 0.75kw and a water flow rate of 6m³ / h. 3 ·h -1 The maximum head is 14m, and the frequency is 50Hz. Of course, adjustments can be made according to the actual size of the greenhouse and the degree of water volume regulation. When the temperature in the greenhouse is too high, the booster pump can be started to increase the water flow rate and volume, thereby increasing the heat dissipation capacity of the fins outside the greenhouse and effectively reducing the greenhouse temperature.

[0044] In some embodiments, the heat absorption module 24 includes several indoor heat exchangers 241 and several hot water storage bags 242; wherein, multiple indoor heat exchangers 241 are connected in series, and some hot water storage bags 242 are connected in series with the indoor heat exchangers 241, while the remaining hot water storage bags 242 are connected in parallel with the indoor heat exchangers 241. When dissipating heat from the interior space of the greenhouse, it is necessary to maintain the stability of the interior under normal conditions, and at the same time, it is necessary to be able to quickly adjust the temperature when there is a sudden abnormality. In this embodiment, several hot water storage bags 242 are used as the main heat exchanger. On the one hand, the parallel hot water storage bags can achieve temperature control during daily operations, and on the other hand, the series-connected hot water storage bags 242 and the indoor heat exchangers 241 can achieve rapid temperature control, thus achieving the purpose of rapid adjustment.

[0045] Specifically, the inlet flow of the heat exchanger can be directly connected to the water storage tank, and the outlet flow can be connected to the water storage pool. Similarly, the inlet flow of the hot water storage bag can be directly connected to the water storage tank, and the outlet flow can be connected to the water storage pool. Alternatively, the heat exchanger and hot water storage bag can be connected sequentially from the water storage tank to the return water storage pool.

[0046] like Figure 1 As shown, the distribution pipeline of the water storage tank 21 has three flow paths. One flow path connects to the heat dissipation module 23 (i.e., the outdoor radiator 231) and ultimately returns to the water storage tank 11 through the collection pipeline to achieve a closed loop. Another flow path is a series return flow formed by the indoor heat exchanger 241 and the series-connected hot water storage bags 242, which also ultimately returns to the water storage tank 11 through the collection pipeline to achieve a closed loop. The remaining flow path connects to the parallel-connected hot water storage bags 242, which return to the water storage tank 11 through the collection pipeline to achieve a closed loop. This method enables graded treatment of temperature dissipation within the main greenhouse structure 10, allowing for targeted handling of normal and abnormal conditions, improving processing efficiency, and reducing energy consumption during daily use.

[0047] In a specific implementation, the main body of the hot water storage bag 242 is a polyvinyl chloride (PVC) hot water storage bag 242, and the specifications of the hot water storage bag 242 are 10m in length and 40cm in diameter. The water bags are connected end to end by a connecting pipe to form a series structure. This method facilitates the installation and connection of the hot water storage bag 242 and reduces the difficulty of its connection and installation.

[0048] Specifically, by using the hot water storage bag 242 as the main heat exchange structure, the water circulation in the circulating water path can be made more stable, improving the overall system stability. Furthermore, the water bag design facilitates arrangement and reduces operating and maintenance costs.

[0049] In conjunction with the above embodiments, such as Figure 1As shown, multiple indoor heat exchangers 241 connected in series are located on one side of the main greenhouse structure 10 along its length, and multiple hot water storage bags 242 connected in series are located on the opposite side of the indoor heat exchangers 241. By placing the hot water storage bags 242 and the indoor heat exchangers 241 on opposite sides, temperature regulation on both sides can be achieved, which improves the flexibility of indoor temperature regulation.

[0050] Specifically, the series-connected indoor heat exchanger 241 is located on the north side of the main greenhouse structure 10, while the series-connected hot water storage bag is located on the south side of the main greenhouse structure. By setting up the different heat absorption bodies on the north and south sides, the temperature of different areas in the greenhouse can be flexibly adjusted.

[0051] Understandably, the temperature on the south side of the main greenhouse structure 10 is higher than that on the north side because in the Northern Hemisphere, sunlight is mainly concentrated on the south side. The south side of the greenhouse receives more solar radiation, resulting in higher daytime temperatures. In this embodiment, the hot water storage bag 242 on the south side is in direct contact with the ground, which cools the soil in that area, preventing the soil temperature from becoming too high and affecting crop growth.

[0052] In conjunction with the above embodiments, a first regulating valve is provided on the inlet connecting pipe of the first hot water storage bag 242 in a series connection, and a second regulating valve is provided on the outlet connecting pipe of the last hot water storage bag 242. The first and second regulating valves are used to regulate the flow rate of the circulating water path. The flow rate of the water in the hot water storage bag 242 affects the temperature control rate of this part. In this embodiment, by setting control valves at both ends, the flow rate can be adjusted according to demand, thereby improving the flexibility of adjustment.

[0053] Specifically, such as Figure 1 As shown, a control valve is installed on the connecting pipe at the end of the heat exchanger series section, and the return end of the outdoor radiator 231 flow path shares a return manifold with the return end of the heat exchanger series section. That is, the indoor heat exchanger 241 series section and the outdoor radiator 231 series section are connected in parallel and are connected in series with the hot water storage bag 242 series section. This makes the water temperature of the hot water storage bag 242 series section lower than the water temperature flowing out of the indoor heat exchanger 241 series section during adjustment, thus achieving effective temperature regulation on this side.

[0054] Understandably, the first and second regulating valves allow for cyclical temperature regulation and stabilize the soil temperature near the roots. In summer, the regulating valves adjust the water flow rate and volume in each water bag. Based on differences in heat capacity within the greenhouse space, the regulating valves in the larger areas need to be larger, allowing for faster water flow and volume on the east and west sides to accelerate heat absorption and exchange. The east and west sides can have lower flow rates. In winter, the opposite approach is taken: increased flow rate and velocity on the east and west sides, and decreased flow rate in the middle, adjusted according to the specific conditions.

[0055] It should be noted that in the series structure, the circulating water has a specific flow direction. The first hot water storage bag 242 is the one through which the circulating water flows first, and the last hot water storage bag 242 is the one through which the circulating water flows last. By setting regulating valves at the beginning and end of the series section, the flow speed of the series section can be controlled, thereby achieving flexible control of the cooling efficiency of this part.

[0056] In conjunction with the above embodiments, the remaining hot water storage bags 242 are located within the rows of cultivated crops inside the main greenhouse structure 10. By placing the hot water storage bags 242 within the row spacing, temperature regulation can be achieved more quickly, and the surrounding soil can be cooled.

[0057] Specifically, the hot water storage bag 242 is connected in series with the indoor heat exchanger 241 and distributed on the east and west sides, while the hot water storage bag 242 and the parallel part of the indoor heat exchanger 241 are distributed on the south and north sides. This arrangement ensures that the hot water storage bag 242 and the indoor heat exchanger 241 are evenly distributed within the internal space of the greenhouse main structure 10, improving the uniformity of heat dissipation. The hot water storage bag and the heat exchanger can also operate independently, with the return water flow directly connected to the water storage tank.

[0058] Another aspect of the present invention provides a control method for controlling the water circulation temperature control buffer system of any of the above-mentioned solar greenhouses, comprising the following steps: Step S10: Select the control mode based on the greenhouse ambient temperature. When the control module 30 outputs control information, it needs to select the control model based on the greenhouse ambient temperature and realize automatic control of the system based on the control model.

[0059] Specifically, different control modes are invoked based on the ambient temperature inside the greenhouse to send control signals and control various components.

[0060] Step S20: Based on the selected control mode and in conjunction with temperature and liquid level information, control the operation of at least one of the circulating pump 22 and / or the booster pump 26, or control the operation of at most one of the heat pump unit 25 and / or the circulating pump 22. After the control mode is selected, the operation control of the components can be achieved through feedback information.

[0061] Specifically, when the liquid level is lower than a preset threshold, the circulation pump 22 is activated to transfer water from the storage tank 11 to the storage tank 21; when t1 ≤ greenhouse ambient temperature ≤ t2 (during high summer temperatures), and the temperature is higher than a preset first temperature threshold, the booster pump 26 is controlled to operate; when t3 ≤ greenhouse ambient temperature ≤ t4 (during winter temperatures), and the temperature is lower than a preset second temperature threshold, the heat pump unit 25 is controlled to operate; where t4 <t1。

[0062] Specifically, when the temperature is higher than the set temperature during spring, summer, autumn, and winter, this embodiment uses the summer and winter temperature ranges as the conditions for selecting the control mode. In winter, the external circulation is shut off, and outdoor heat dissipation is not carried out. When the liquid level in the water storage tank 21 is lower than the set value, generally when the water level is 10-20cm below the bottom of the tank, the circulation pump 22 is started to pump water from the water storage tank 11 into the water storage tank 21. The high-pressure water potential difference created by the higher-level water storage tank 21 drives the water circulation of the hot water storage bag 242, the outdoor radiator, and the indoor heat exchanger 241. During spring, summer, and autumn, when the temperature inside the greenhouse is sensed to be higher than the set value, generally 28-30℃, the booster pump 26 is started to accelerate the water flow rate and increase the water volume circulation, thereby accelerating heat dissipation and lowering the temperature as quickly as possible. In winter, the outdoor circulation of the greenhouse is shut off, and the water in the radiator and pipes is drained to prevent freezing and damage to the pipes. When the daytime temperature in the greenhouse drops below 10-15℃, the air-source heat pump can be activated to heat the water circulation system, increasing its heat capacity to cope with the low day-night temperatures. Alternatively, circulation pump 22 can be activated to accelerate water flow and increase circulation capacity, speeding up heat exchange within the greenhouse to stabilize and raise the temperature, thus meeting the needs of crop production and development. The settings can be adjusted based on the cultivated crops, management requirements, greenhouse size, and operational performance measurements.

[0063] The following describes the specific implementation methods for each control quantity in the control module described above. Details are as follows: Based on the experimental data and physical model of the water circulation temperature control buffer system of a solar greenhouse, the mathematical formula for estimating the required water volume and heat matching of the solar greenhouse is derived as follows: The heat exchange capacity of water circulation is derived from the sensible heat exchange formula, which is: ; in, For the heat exchange capacity (J), based on the heat dissipation performance of the outdoor radiator 231 selected from the experimental results, the heat exchange range was chosen to be 85.4-123.1J; where: The mass (kg) of water needs to be calculated based on the flow rate; The specific heat capacity of water is taken as 4186 J / (kg·K); The measured temperature difference (K) between the water inlet and outlet is 4.6℃.

[0064] Since heat exchange efficiency is directly related to water volume, water flow rate, heat exchange performance of radiators, and ambient temperature, in order to simplify the calculation, the inlet and outlet temperature difference of the heat exchange fins in the test group is used as the basis for calculation. Since the inlet and outlet temperature difference of the heat exchange fins in the test group already includes the influence of ambient temperature, in order to simplify the calculation, the ambient temperature is ignored in this calculation. The matching calculation of water capacity and heat can be calculated using the following formula for preliminary estimation.

[0065] Calculate the required water flow rate per unit time Assuming the system running time is t (seconds), the heat exchange... Where: p is the heat exchange power (W).

[0066] The mass flow rate can be obtained from the sensible heat formula: ; Volumetric flow rate: ; in, kg / m 3 A forced circulation water flow rate of 6 m³ / h is selected, corresponding to a mass flow rate of φ = 6 × 1000 / 3600 ≈ 1.67 kg / s. Substituting these values ​​into the formula, the heat dissipation power can be estimated. ; The actual heat exchange was 85.4-123.1 J, indicating that the cooling capacity in the experiment was an instantaneous value or that there were other heat losses, which need to be corrected in conjunction with the COP value.

[0067] The energy balance COP (coefficient of performance) is defined as the ratio of heat exchange to input power. ; The COP value is 1.5-3.7, assuming the input power... (Corresponding to the circulating pump power), then the upper limit of heat exchange is: ; According to calculations, the water required to exchange 1 kJ of heat is V. waterApproximately 0.052L; if the water flow rate is 6 m³ / h, it can continuously provide 2778W of heat exchange power (when COP=3.7). Therefore, increasing the water flow rate or temperature difference can increase the heat exchange capacity, but energy consumption and efficiency (COP value) must be balanced. Taking a total greenhouse area of ​​1500m² as an example, based on thermal calculations, it can be preliminarily calculated that increasing the number of finned radiators to 15-20 sets will provide the best heat dissipation effect and meet the needs of a larger heat load. Based on the heat exchange demand and circulation efficiency, the water volume needs to be increased to improve the heat storage capacity. It is recommended that the total water volume of the greenhouse water circulation temperature control buffer system be increased to approximately 25-30m³, and the number of hot water storage bags be set to 15-20. The water volume can be adjusted according to the actual installation and application. Water bags can be laid between the cultivation rows. This configuration can significantly improve the heat storage and release effect and basically meet the needs of high-temperature environment control in summer. This estimate is based on the maximum set value to allow for the use of more water volume to regulate temperature balance.

[0068] As shown above, and verified by summer testing, the results indicate that, especially under sunny conditions, the maximum temperature difference can reach 7.1℃, and the COP reaches 1.5–3.7. This demonstrates that the energy efficiency ratio of the water circulation temperature control buffer system in solar greenhouses is superior to traditional ventilation and cooling methods. It boasts advantages such as low material cost, simple installation and maintenance, and low operating cost. Installation between cultivated plants can effectively balance rhizosphere temperature, which is beneficial to normal crop growth and development. The system shows promising application prospects and plays a positive role in year-round temperature control and balance management. Through the synergistic effect of closed-loop water circulation and finned radiators, this system achieves precise control of the temperature and humidity environment in solar greenhouses during summer, providing reliable technical support for energy-efficient production in facility agriculture.

[0069] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment uses water as the circulating medium. Heat is absorbed from the greenhouse into the water body via the heat exchanger 241 and water bags inside the greenhouse, flowing by gravity to an underground water tank. The circulating pump 22 pumps the water from the underground tank to a high-level water tank. The high-level water tank, driven by high pressure, circulates the water through a closed-loop pipeline back to the heat exchange plates and water bags inside the greenhouse, exchanging heat again. A control system is established based on water level sensors and temperature, and this cycle continues. When the temperature is too high, a booster pump can be activated to accelerate the water flow, enhance heat exchange, and achieve temperature "peak shaving and valley filling" in the greenhouse, balancing the temperature and creating excellent environmental conditions for crop growth. When the temperature is too low in winter, an air-source heat pump can be activated during the day to heat the water circulation system inside the greenhouse, improving the temperature control buffering capacity in winter. Furthermore, the overall structure is simple, easy to install and construct, operates stably and reliably, achieves cost savings and energy reduction, and has significant effects with low operating costs.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water circulation temperature control and buffering system for a solar greenhouse, characterized in that, include: The main structure of the greenhouse includes a water storage tank pre-installed beneath the ground within the main structure. A water circulation assembly includes a water storage tank, a circulation pump, a heat pump unit, and a temperature control unit. The circulation pump is located on a water supply pipeline between the water storage tank and the water storage tank, and the water storage tank forms a fluid loop with the water storage tank through the water supply pipeline. The heat pump unit is connected to the water storage tank through a circulation pipeline to form a water circulation heating system. The inlet of the temperature control unit is connected to the water storage tank through a distribution pipeline, and the return end of the temperature control unit is connected to the water storage tank through a collection pipeline. The control module includes a temperature acquisition module for sensing indoor temperature; The temperature control unit includes a heat absorption module and a heat dissipation module connected in parallel. The heat dissipation module is located outside the main structure of the greenhouse to dissipate heat and cool the circulating water in the system. The heat absorption module is located inside the main structure of the greenhouse to absorb heat and cool the internal space of the main structure of the greenhouse and the soil. The bottom elevation of the water storage tank is higher than that of the temperature control unit, and a liquid level sensor is installed inside the water storage tank. The control module is configured to control the operation of the circulating pump and the heat pump unit based on temperature and liquid level information. The heat absorption module includes several indoor heat exchangers and several hot water storage bags; In this configuration, multiple indoor heat exchangers are connected in series, and at least one hot water storage bag is connected in series with the indoor heat exchanger, and at least one hot water storage bag is connected in parallel with the indoor heat exchanger. Multiple indoor heat exchangers connected in series are located on one side of the main structure of the greenhouse along its length, and multiple hot water storage bags connected in series or in parallel are provided on the opposite side of the indoor heat exchangers.

2. The solar greenhouse water circulation temperature control and buffer system according to claim 1, characterized in that, The heat dissipation module includes multiple outdoor radiators connected in series. The water inlet of the outdoor radiator is connected to the water storage tank through the distribution pipe, and the water return of the outdoor radiator is connected to the heat absorption module and the water storage tank in sequence through the collection pipe.

3. The solar greenhouse water circulation temperature control and buffer system according to claim 2, characterized in that, A booster water circuit is connected in parallel to the water supply line between the outdoor radiator and the water storage tank. A booster pump is installed on the booster water circuit, and the booster pump is electrically connected to the control module.

4. The solar greenhouse water circulation temperature control and buffer system according to claim 1, characterized in that, The first regulating valve is provided on the inlet connecting pipe of the first hot water storage bag in the series of multiple hot water storage bags, and the second regulating valve is provided on the outlet connecting pipe of the last hot water storage bag. The first regulating valve and the second regulating valve are used to regulate the flow rate of the circulating water circuit.

5. The solar greenhouse water circulation temperature control and buffer system according to claim 1, characterized in that, The remaining portion of the hot water storage bags are placed between the rows of cultivated crops within the main structure of the greenhouse, so that the soil is equipped with hot water storage bags.

6. The solar greenhouse water circulation temperature control and buffer system according to claim 1, characterized in that, The main body of the hot water storage bag is a polyvinyl chloride hot water storage bag.

7. A control method for controlling the water circulation temperature control and buffer system of a solar greenhouse according to any one of claims 1-6, characterized in that, Includes the following steps: Based on the selection of control modes according to the ambient temperature inside the greenhouse; Based on the selected control mode, and in conjunction with temperature and liquid level information, control at least one action of the circulating pump and / or booster pump, or control at most one action of the heat pump unit and / or circulating pump.

8. The control method according to claim 7, characterized in that, Controlling the operation of one or both of the circulating pump, booster pump, and heat pump unit, based on the selected control mode, specifically includes the following steps: When the liquid level is lower than the preset liquid level threshold, the circulation pump is turned on to transport the water in the water storage tank to the water storage tank. When t1≤greenhouse ambient temperature≤t2, and the temperature information is higher than the preset first temperature threshold, control the booster pump to run; When t3≤the ambient temperature inside the greenhouse≤t4, and the temperature information is lower than the preset second temperature threshold, the heat pump unit is controlled to operate; Among them, t4 <t1。

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