A passive and active thermal storage wall system based on a sunlight greenhouse

Abstract

The utility model discloses a kind of active and passive heat storage wall body regulation and control systems based on sunlight greenhouse, it is related to the renewable energy application field of facility agricultural building, including the active and passive heat storage wall body being arranged in the north side of greenhouse, solar air heat collection module, ground source heat pump module and indoor air circulation module, heat collector heat storage mode, water tank heat release mode, ground source heat pump supplementary heating mode, ground loop circulation cooling mode, ground source heat pump cooling mode and transition season soil heat supplement mode can be freely switched between. Through the intelligent switching and collaborative work of six modes, integrated regulation and control of a set of system to meet the whole year cold and heat demand is realized, not only greatly improve energy utilization efficiency, reduce operating cost, and fundamentally solve the soil heat imbalance problem of ground source heat pump, ensure the long-term high efficiency and stability of system. Meanwhile through optimized indoor airflow organization, create more suitable, more uniform growth environment for crops.

Description

Technical Field

[0001] This utility model relates to the field of renewable energy application in facility agriculture buildings, and in particular to a control system for active and passive heat storage walls based on a solar greenhouse. Background Technology

[0002] As an important agricultural infrastructure in northern regions, solar greenhouses can provide crops with a relatively stable temperature and humidity environment, making winter agricultural production feasible and ensuring efficient production throughout the year.

[0003] For a long time, the cooling measures of solar greenhouses have relied solely on natural ventilation through openings in the enclosure structure. In winter, heating is achieved through solar radiation transmitted through the front roof. However, high outdoor temperatures in summer reduce the efficiency of natural ventilation, and indoor air temperatures can exceed 40°C at midday. Frequent cloudy and snowy days in winter significantly reduce solar radiation intensity, making it difficult for indoor air temperatures to meet the minimum requirements for most crops. These control measures are constrained by outdoor weather conditions, have weak self-control capabilities, and limited effectiveness in regulating room temperature. High summer temperatures can cause leaf and fruit scorching and plant wilting, while persistently low winter temperatures can cause frost damage, yield reduction, or even crop failure. These extreme temperature environments can result in crop yield reductions of 10%-50%. Traditional solar greenhouses struggle to provide a suitable growing environment for crops in the face of extreme winter and summer temperatures; therefore, efficient temperature control measures are needed to meet the year-round operation requirements of the greenhouse.

[0004] To improve the thermal environment inside greenhouses, many scholars have conducted relevant research. For example, Chinese utility model patent ZL202321750582.6 discloses a cross-seasonal energy storage heating system. This system uses solar collectors coupled with a ground source heat pump to provide heating and cooling for buildings such as farmhouses and greenhouses. The system effectively utilizes solar and geothermal energy, and achieves cross-seasonal heat storage by heating water tanks with solar energy during the non-heating season. However, its summer operation relies solely on the ground source heat pump, resulting in high energy consumption. It fails to fully utilize the advantage of lower soil temperatures, and the system does not adequately consider the airflow distribution within the greenhouse. Another Chinese utility model patent, ZL 202421051353.X, discloses a long-term solar-powered soil hydration salt system that can be used for cross-seasonal heat storage and heating. This system is simple to operate and maintain, but its heating controllability is low. Under different meteorological parameters in winter, there is a lag effect and heat waste in the heating.

[0005] Therefore, there is an urgent need in this field for a solar greenhouse environmental control system that can achieve precise, efficient, and energy-saving temperature control throughout the year, optimize indoor airflow organization, and avoid soil thermal imbalance. Utility Model Content

[0006] In order to overcome the above-mentioned defects of the prior art, this utility model provides an active and passive heat storage wall control system based on a solar greenhouse to solve the problems existing in the background art.

[0007] This utility model provides the following technical solution: a control system for active and passive heat storage walls in a solar greenhouse, comprising an active and passive heat storage wall, a solar air collector module, a ground source heat pump module, and an indoor air circulation module, all installed on the north side of the greenhouse. The active and passive thermal storage wall is embedded with water tanks connected in series. The solar air collector module includes a solar air collector and a fan connected by a duct. The duct passes through the active and passive heat storage wall and exchanges heat with the water tank. The ground source heat pump module includes a ground source heat pump unit and a buried pipe heat exchanger system. The load side of the ground source heat pump unit is connected to the water tank through a water pipe, and its source side is connected to the buried pipe heat exchanger system through a water pipe. The indoor air circulation module includes a main supply air duct, a branch supply air duct, a main return air duct, and a branch return air duct, and is connected to the active and passive heat storage wall through the air duct to form an airflow circulation path; The system is equipped with multiple valves on its air ducts and water pipes. By controlling the opening and closing of these valves, the system can switch between the following modes: collector heat storage mode, water tank heat release mode, ground source heat pump supplementary heating mode, buried pipe circulation cooling mode, ground source heat pump cooling mode, and transitional season soil supplementary heating mode.

[0008] Preferably, the thickness of the active and passive heat storage wall is 510mm, and from the inside out, it includes: a 120mm thick inner brick layer, a 150mm thick middle layer inlaid with the water tank, and a 240mm thick outer brick layer.

[0009] Preferably, the number of water tanks is five, connected in series; the dimensions of a single water tank are 1500mm in length, 800mm in width, and 150mm in thickness, with its lower surface 800mm from the ground and its left and right sides 650mm from the wall surface.

[0010] Preferably, the solar air collector is a three-tube double parabolic trough air collector, installed on the top of the north wall of the greenhouse.

[0011] Preferably, the supply air branch pipe and the return air branch pipe are fixed to the steel frame structure of the front roof of the greenhouse; the supply air branch pipe is located at the lower part of the greenhouse, and the return air branch pipe is located at the upper part of the greenhouse, together forming a bottom-supply and top-return airflow organization.

[0012] Preferably, the valves include a duct three-way valve for controlling the air path and a water pipe three-way valve and a water pipe butterfly valve for controlling the water path.

[0013] Preferably, the buried pipe heat exchanger system is a vertical U-shaped buried pipe with a depth of 120 meters and a top height of 10 meters from the ground surface.

[0014] Preferably, it also includes a main controller, which is connected to the temperature detector signal to receive temperature signals and automatically control the start-up, shutdown and switching of the valves, fans, water pumps and ground source heat pump units to achieve automatic switching of different operating modes.

[0015] Preferably, the system uses water as the medium for heat storage in the walls and heat exchange with the soil, and air as the medium for solar heat collection and heat exchange with the indoor environment.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This invention deeply integrates active solar heat collection, passive wall heat storage, and ground source heat pump technology. Compared to previous greenhouse temperature control systems with relatively simple functions, it achieves a unified year-round closed-loop control of winter heating, summer cooling, and transitional season soil heating, meeting the year-round production needs of crops. 2. This invention introduces a ground source heat pump as a flexible and reliable supplementary heat source. In summer, it fully utilizes the natural low temperature of the medium-deep soil through a tiered utilization mode of "direct circulation through buried pipes → enhanced cooling by heat pump." Compared to the instability of single solar heating, it prioritizes the use of free cooling sources, reducing cooling energy consumption and operating costs. 3. This invention actively stores summer indoor waste heat and surplus solar energy through a transitional season soil heating mode. In the soil, it effectively compensates for the "cold accumulation" of soil caused by heat pump extraction in winter, avoiding the gradual decline of soil temperature year by year, thus ensuring the long-term stable operating efficiency of the ground source heat pump unit; 4. This utility model system stores the waste heat resources of summer and transition seasons through the soil across seasons and utilizes them in winter. This method not only improves the all-time utilization rate of solar energy, but also further reduces the total energy consumption of winter heating, realizing the spatial and temporal transfer and efficient circulation of energy; 5. This utility model adopts a duct system bound to the front roof of the greenhouse to construct a scientific airflow organization of "downward supply and upward return". This layout has been verified to improve the temperature uniformity of the crop canopy area, increase the area ratio of the suitable airflow velocity zone, and create a better microenvironment for crop growth. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the component structure of the system of this utility model.

[0018] Figure 2 This is a schematic diagram of the indoor air supply and return structure of this utility model.

[0019] Figure 3 This is a schematic cross-sectional view of the greenhouse according to this utility model.

[0020] The attached diagram is labeled as follows: 1. Duct three-way valve; 2. Duct distributor; 3. Solar air collector; 4. Duct collector; 5. Duct three-way valve; 6. Fan; 7. Water tank; 8. Water pipe butterfly valve; 9. Water pump; 10. Water pump; 11. Water pipe three-way valve; 12. Water pipe three-way valve; 13. Water pipe three-way valve; 14. Water pipe butterfly valve; 15. Ground source heat pump unit; 16. Buried pipe heat exchanger system; 17. Supply air branch pipe; 18. Return air branch pipe; 19. Supply air main pipe; 20. Return air main pipe; 21. Steel frame structure. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of the present invention.

[0022] This utility model provides a control system for active and passive heat storage walls based on a solar greenhouse, such as... Figure 1-3 As shown, the system mainly consists of four parts: the main greenhouse structure, the solar air collection module, the ground source heat pump module, and the indoor air circulation module.

[0023] The main body of the greenhouse consists of 500mm thick red brick gable walls on the east and west sides, a front roof covered with EVA film, and a specially designed and modified active and passive heat storage wall on the north side. The north wall has a total thickness of 510mm and adopts a composite structure: from the inside out, it consists of a 120mm thick red brick layer, a 150mm thick brick layer with five stainless steel water tanks embedded in series, and a 240mm thick red brick layer.

[0024] The structural design of the main body of the greenhouse not only ensures the structural strength of the walls but also forms a passive heat storage system. Each water tank 7 measures 1500mm in length, 800mm in width, and 150mm in thickness, with its lower surface 800mm from the indoor floor and its left and right sides 650mm from the inner surface of the walls. The five water tanks are connected in series by water pipes to form a water-based heat storage unit.

[0025] The air duct extends from the solar air collector 3, enters the wall, and passes sequentially through the space between the five water tanks 7, where it exchanges heat thoroughly with the tank walls. Finally, it returns to the solar air collector 3, forming a closed air heat exchange loop. This design efficiently transfers actively collected solar energy to the wall bricks via the air medium for passive heat storage and to the water in the tanks for active heat storage.

[0026] The solar air collector module mainly includes a three-tube double parabolic trough solar air collector 3 installed on the top of the north wall, a variable frequency fan 6, a duct distributor 2, a duct collector 4, and duct three-way valves 1 and 5 for switching air paths. This module is the main heat source for the system during the daytime in winter.

[0027] The ground source heat pump module mainly includes a ground source heat pump unit 15, a buried pipe heat exchanger system 16, water pumps 9 and 10, water pipe three-way valves 11, 12, and 13, as well as water pipe butterfly valves 8 and 14. The buried pipe heat exchanger system 16 is a vertical U-shaped pipe buried at a depth of 120 meters. At this depth, the soil temperature remains stable at around 14℃ year-round, serving as a heat source and cold source. The load side of the ground source heat pump unit 15 is connected to the water tank 7 via pipelines, allowing for the heating or cooling of the water in the tank. Its source side is connected to the buried pipe 16 via pipelines, enabling heat exchange with the soil.

[0028] The indoor air circulation module includes supply air branch pipes 17 and return air branch pipes 18, which are tied to the steel frame structure 21 on the front roof of the greenhouse, as well as supply air main pipes 19 and return air main pipes 20 connected to them. The supply air branch pipes 17 are evenly distributed in the lower part of the greenhouse, and the return air branch pipes 18 are distributed in the upper part of the greenhouse, forming a "bottom supply, top return" airflow organization. Cold air is supplied from the bottom, naturally warms up and rises, and is discharged from the upper return air vents, effectively avoiding temperature stratification and airflow dead zones as in traditional methods. This increases the area ratio of suitable airflow velocity zones at different crop canopy heights, which is more beneficial to crop growth.

[0029] The system receives temperature sensor signals from the greenhouse through a central controller (not shown in the diagram), and automatically determines and switches operating modes based on preset logic. The component connections, operating processes, and resulting technical effects for each mode are detailed below: The solar collector heat storage mode is generally used during the daytime in winter: Duct three-way valves 1 and 5 are switched to allow the airflow to form a loop through distributor 2, collector 3, and collector 4. Fan 6 starts, driving air that has been heated by solar energy in collector 3. The air then flows through the ducts inside the wall, efficiently transferring heat to the water in water tank 7 for active heat storage and to the wall bricks for passive heat storage. The cooled air returns to the collector for reheating, thus completing the heat storage cycle. This mode fully utilizes free solar energy to store energy for nighttime heating.

[0030] The water tank heat release mode is generally used during winter nights: Duct three-way valves 1 and 5 are switched to connect the return air main duct 20 and the supply air main duct 19. Cooler indoor air is drawn in from the upper return air branch duct 18, flows through the return air main duct 20, and is driven by the fan 6. It then flows through the north wall duct to exchange heat with the heat storage water tank 7 and the wall. The heated air is then returned to the room through the supply air main duct 19 and the lower supply air branch duct 17 to heat the greenhouse. This mode releases solar energy stored during the day, achieving energy transfer over time.

[0031] The ground source heat pump supplemental heating mode is generally used when winter is extremely cold or heat storage is insufficient: the indoor air circulation section is the same as the heat release mode of water tank 7. Simultaneously, water pumps 9 and 10 are turned on, and the heating mode of the ground source heat pump unit 15 is activated. The water circuit is as follows: on the load side, water in water tank 7 circulates through butterfly valve 8, heat pump unit 15, water pump 9, and three-way valve 12, and is heated by the heat pump; on the source side, antifreeze circulates through heat pump unit 15, water pump 10, three-way valve 11, buried pipe 16, and three-way valve 13, extracting heat from the soil. This mode actively heats the water in water tank 7 through the ground source heat pump, greatly enhancing the heating capacity of indoor air and ensuring the stability and reliability of heating under extreme weather conditions.

[0032] The underground pipe circulating cooling mode is generally used in summer: the indoor air circulation is the same as the water tank heat dissipation mode, in which case the water tank 7 contains cold water. Simultaneously, the water circulation works as follows: the ground source heat pump unit 15 is shut off, and by controlling three-way valves 11, 12, and 13, the water pump 9 drives the water in the water tank 7 through three-way valve 12, butterfly valve 14, underground pipe 16, and three-way valve 11 to form a loop. The water is cooled by flowing through the low-temperature underground pipe 16 and then returns to the water tank 7, thus continuously providing cooling for the indoor air flowing through the walls. This mode directly utilizes the natural cold source of the soil, achieving near-zero energy consumption and free cooling.

[0033] Ground source heat pump cooling mode is generally used when direct cooling from buried pipes is insufficient during the high temperatures of summer. The component connection method is the same as that of ground source heat pump supplementary heating mode, but the ground source heat pump unit 15 switches to cooling mode. At this time, the heat pump unit 15 provides colder water to the water tank 7, while releasing the condensation heat into the soil through the buried pipe 16 to meet the higher cooling load demand. This mode serves as an enhanced cooling method.

[0034] The transitional season soil heating mode is generally applied in spring and autumn: the component connection method is the same as the buried pipe circulation cooling mode. At this time, the waste heat of the indoor air or the excess heat generated by the daytime collector is absorbed by the water in water tank 7, and then released into the relatively cool soil through the buried pipe circulation. The purpose is to replenish the soil with heat, directly compensate for and correct the drop in soil temperature caused by the large amount of heat taken in winter, i.e., "cold accumulation".

[0035] Through the intelligent switching and coordinated operation of the above six modes, an integrated control system is achieved to meet the year-round heating and cooling needs, and a cross-seasonal energy cycle of "summer waste heat / transitional season heat replenishment stored in the soil - winter heat extraction from the soil" is completed. This not only significantly improves energy utilization efficiency and reduces operating costs, but also fundamentally solves the soil thermal imbalance problem of ground source heat pumps, ensuring the long-term high efficiency and stability of the system. At the same time, through optimized indoor airflow organization, a more suitable and uniform growing environment is created for crops.

[0036] Several points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change.

[0037] The above description is only a preferred embodiment of the present utility model. The protection scope of the present utility model is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present utility model should be included in the protection scope recorded in the claims.

Claims

1. A control system for active and passive heat storage walls in a solar greenhouse, characterized in that: It includes active and passive heat storage walls, solar air collector modules, ground source heat pump modules, and indoor air circulation modules, all located on the north side of the greenhouse. The active and passive heat storage wall is embedded with water tanks (7) connected in series. The solar air collector module includes a solar air collector (3) and a fan (6) connected by a duct. The duct passes through the active and passive heat storage wall and exchanges heat with the water tank (7). The ground source heat pump module includes a ground source heat pump unit (15) and a buried pipe heat exchanger system (16). The load side of the ground source heat pump unit (15) is connected to the water tank (7) through a water pipe, and its source side is connected to the buried pipe heat exchanger system (16) through a water pipe. The indoor air circulation module includes a main air supply pipe (19), a branch air supply pipe (17), a main return air pipe (20), and a branch return air pipe (18), and is connected to the active and passive heat storage wall through air ducts to form an airflow circulation path; The system is equipped with multiple valves on the air ducts and water pipes. By controlling the opening and closing of these valves, the system can switch between the following modes: collector heat storage mode, water tank heat release mode, ground source heat pump supplementary heating mode, buried pipe circulation cooling mode, ground source heat pump cooling mode, and transitional season soil supplementary heating mode.

2. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The thickness of the active and passive heat storage wall is 510mm, and from the inside to the outside it includes: an inner brick layer of 120mm thickness, a middle layer of 150mm thickness in which the water tank (7) is embedded, and an outer brick layer of 240mm thickness.

3. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The number of water tanks (7) is five, connected in series; the dimensions of a single water tank are 1500mm long, 800mm wide, and 150mm thick, with its lower surface 800mm from the ground and its left and right sides 650mm from the wall surface.

4. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The solar air collector (3) is a three-tube double parabolic trough air collector, which is installed on the top of the north wall of the greenhouse.

5. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The supply air branch pipe (17) and return air branch pipe (18) are fixed on the steel frame structure (21) of the front roof of the greenhouse; the supply air branch pipe (17) is located at the lower part of the greenhouse and the return air branch pipe (18) is located at the upper part of the greenhouse, together forming a downward supply and upward return airflow organization.

6. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The valves include duct three-way valves (1, 5) for controlling the air path, and water pipe three-way valves (11, 12, 13) and water pipe butterfly valves (8, 14) for controlling the water path.

7. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: The buried pipe heat exchanger system (16) is a vertical U-shaped buried pipe with a depth of 120 meters and a top distance of 10 meters from the ground surface.

8. The active and passive heat storage wall control system based on a solar greenhouse according to claim 1, characterized in that: It also includes a main controller, which is connected to the temperature detector signal to receive temperature signals and automatically control the start-up, shutdown and switching of the valves, fans (6), water pumps (9, 10) and ground source heat pump units (15) to achieve automatic switching of different operating modes.

9. A control system for active and passive heat storage walls in a solar greenhouse according to claim 1, characterized in that: The system uses water as the medium for heat storage in the walls and heat exchange with the soil, and air as the medium for solar energy collection and heat exchange with the indoor environment.

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