A solar greenhouse heating system and a method of operation thereof

Abstract

The present application belongs to the technical field of greenhouse heating, and discloses a sunlight greenhouse heating system and a working method thereof, which comprises two solar heat storage and exchange subsystems; the two solar heat exchange subsystems are respectively located at two ends of a soil-air heat exchange subsystem; the soil-air heat exchange subsystem comprises soil heat exchange pipelines; two air supply dry pipes are respectively arranged at two ends of the soil heat exchange pipelines; each air supply dry pipe is provided with a first air inlet, a second air inlet, a third air inlet and an air outlet; the first air inlet is in communication with air in the greenhouse, the second air inlet is in communication with atmosphere outside the greenhouse, and the third air inlet is connected with an outlet of the solar heat storage and exchange subsystem; two ends of the air supply dry pipe are respectively connected with the air outlets of the two air supply dry pipes; an axial flow fan is arranged in the air supply dry pipe, and an electric heater is arranged at an end of the air supply dry pipe; the present application realizes greenhouse heating by using renewable geothermal energy and solar energy, does not need to consume fossil energy, and greatly strengthens the stability and self-regulating ability of the greenhouse temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of greenhouse heating, in particular to an energy-saving heating system using solar energy and geothermal energy, and more particularly to a sunlight greenhouse heating system and a working method thereof. BACKGROUND

[0002] In agricultural production, it is very common to use sunlight greenhouses for cross-season planting. Sunlight greenhouses play a crucial role in responding to the threat of climate change to agricultural production and have a positive impact on alleviating the food security crisis. Currently, traditional sunlight greenhouses usually use traditional fossil energy for environmental regulation, which has the problems of high consumption of fossil energy, poor self-regulation ability to the environment, and serious environmental pollution, thereby failing to effectively ensure the yield of planted crops. SUMMARY

[0003] In view of the technical problems existing in the prior art, the present application provides a sunlight greenhouse heating system and a working method thereof to solve the technical problems of high consumption of fossil energy, poor self-regulation ability to the environment, and serious environmental pollution of traditional sunlight greenhouses.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0005] The present application provides a sunlight greenhouse heating system, comprising two solar heat storage and exchange subsystems, a soil-air heat exchange subsystem, and an electric heater. The two solar heat exchange subsystems are located at both ends of the soil-air heat exchange subsystem, and are used to heat the air outside the greenhouse using solar energy, and to deliver the heated hot air to the soil-air heat exchange subsystem. The soil-air heat exchange subsystem comprises a soil heat exchange pipeline, two air supply dry pipes, an air supply dry pipe, and an axial flow fan.

[0006] The soil heat exchange pipeline is buried underground in the sunlight greenhouse body, and the two air supply dry pipes are arranged at both ends of the soil heat exchange pipeline. Each air supply dry pipe is provided with a first air inlet, a second air inlet, a third air inlet, and an air outlet. The first air inlet is in communication with the air inside the sunlight greenhouse body, and the second air inlet is in communication with the atmosphere outside the sunlight greenhouse body. The third air inlet of one of the air supply dry pipes is connected to the outlet of one of the solar heat storage and exchange subsystems, and the third air inlet of the other air supply dry pipe is connected to the outlet of the other solar heat storage and exchange subsystem. The inlets of the two solar heat storage and exchange subsystems are in communication with the atmosphere outside the sunlight greenhouse body.

[0007] The air supply main pipe is arranged above the inner ground of the solar greenhouse body, and the two ends of the air supply main pipe are respectively connected to the air supply ports of the two air supply main pipes; the axial flow fan is arranged in the air supply main pipe and placed between the first air inlet and the third air inlet; the electric heater is arranged at the end of the air supply main pipe, and is used to electrically heat the airflow entering the air supply main pipe;

[0008] The heating mode selection process of the solar greenhouse heating system is as follows:

[0009] Determine the nighttime demand load of the solar greenhouse , the nighttime demand load of the solar greenhouse body Compared with the design heating capacity under the preset soil-air heat exchange heating mode , Designed heating capacity under the preset single-side heat storage and heat exchange heating mode And the design heating capacity under the preset soil-air heat exchange heating and solar heat storage heat exchange combined heating mode Compare; according to the heat supply comparison result, obtain the heating mode selection result of the solar greenhouse heating system.

[0010] Furthermore, the two solar thermal storage and heat exchange subsystems have the same structure and both use solar thermal storage and heat exchange devices; wherein the solar thermal storage and heat exchange device includes a solar collector, a thermal storage and heat exchange water tank and a tube bundle heat exchanger;

[0011] The solar thermal collector is arranged at the top of the rear wall of the solar greenhouse body, and the heat storage and heat exchange pool is arranged at the end of the soil-air heat exchanger subsystem; wherein the cold water inlet of the solar thermal collector is connected to the water outlet of the heat storage and heat exchange pool, and the hot water outlet of the solar thermal collector is connected to the water inlet of the heat storage and heat exchange pool;

[0012] The tube bundle heat exchanger is arranged in the water storage and heat exchange pool, the air inlet of the tube bundle heat exchanger is connected to the atmosphere outside the solar greenhouse body, and the air outlet of the tube bundle heat exchanger is connected to the third air inlet; wherein, the tube bundle heat exchanger is used to use the hot water in the heat storage and heat exchange pool to heat the air in the tube bundle heat exchanger.

[0013] Furthermore, the solar thermal storage and heat exchange device further includes a water supply pipeline, a water return pipeline and a submersible pump;

[0014] The inlet end of the water supply pipeline is connected to the water outlet of the heat storage and heat exchange pool, and the outlet end of the water supply pipeline is connected to the cold water inlet of the solar collector; the inlet end of the return water pipeline is connected to the hot water outlet of the solar collector, and the outlet end of the return water pipeline is connected to the water inlet of the heat storage and heat exchange pool; the submersible pump is arranged at the water outlet of the heat storage and heat exchange pool and is connected to the inlet end of the water supply pipeline.

[0015] Furthermore, the soil-air heat exchange subsystem further includes an air supply pipe inside the greenhouse, an air supply pipe outside the greenhouse, and a plurality of air supply branches;

[0016] The inlet end of the greenhouse air supply pipe is connected to the air in the solar greenhouse body, and the outlet end of the greenhouse air supply pipe is connected to the first air inlet; the inlet end of the greenhouse external air supply pipe extends to the outside of the solar greenhouse body and is connected to the atmosphere outside the solar greenhouse body; the outlet end of the greenhouse external air supply pipe is designed in two ways, one of which is connected to the second air inlet and the other is connected to the air inlet of the tube bundle heat exchanger;

[0017] The air supply main pipe is provided with a plurality of air supply holes, the plurality of air supply holes are evenly distributed along the axis of the air supply main pipe, and the plurality of air supply branch pipes are correspondingly arranged at the plurality of air supply holes.

[0018] Furthermore, it also includes a first electric valve, a second electric valve, a third electric valve, a fourth electric valve, a fifth electric valve, a sixth electric valve, a seventh electric valve and an eighth electric valve;

[0019] The first electric valve is arranged at the inlet of the first solar thermal storage and heat exchange subsystem; the second electric valve is arranged on the first air supply main pipe and placed between the first air inlet and the second air inlet of the first air supply main pipe; the third electric valve is arranged at the outlet of the first solar thermal storage and heat exchange subsystem; the fourth electric valve is arranged on the supply air main pipe and is arranged close to one end of the first air supply main pipe; the fifth electric valve is arranged on the supply air main pipe and is arranged close to one end of the second air supply main pipe; the sixth electric valve is arranged on the second air supply main pipe and is placed between the first air inlet and the second air inlet of the second air supply main pipe; the seventh electric valve is arranged at the inlet of the second solar thermal storage and heat exchange subsystem; the eighth electric valve is arranged at the outlet of the second solar thermal storage and heat exchange subsystem.

[0020] Furthermore, it also includes a control subsystem; wherein, the control subsystem includes a greenhouse information acquisition module, an environmental data acquisition module and a load calculation module;

[0021] The greenhouse information collection module is used to collect the temperature in the greenhouse, the relative humidity in the greenhouse, the operating temperature of the solar thermal storage and heat exchange subsystem, and the outlet temperature of the soil-air heat exchanger subsystem;

[0022] The environmental data acquisition module is used for the ambient dry-bulb temperature, solar illumination intensity and ambient wind speed outside the solar greenhouse body;

[0023] The load calculation module is used to calculate the total amount of indoor gas and the total amount of outdoor gas during the first air mixing in the solar greenhouse heating system based on the collected temperature in the greenhouse, the relative humidity in the greenhouse, the operating temperature of the solar thermal storage and heat exchange subsystem, the outlet temperature of the soil-air heat exchanger subsystem, the ambient dry bulb temperature outside the solar greenhouse body, the solar light intensity and the ambient wind speed;

[0024] The opening adjustment module is used to generate and send the opening adjustment instruction of the electric valve to the first electric valve, the second electric valve, the third electric valve, the fourth electric valve, the fifth electric valve, the sixth electric valve, the seventh electric valve and the eighth electric valve according to the total amount of indoor gas and the total amount of outdoor gas during the first air mixing in the solar greenhouse heating system.

[0025] Furthermore, the load calculation module adopts a PID-MPC combined control strategy, specifically including a PID controller and an MPC controller;

[0026] The PID controller is used to determine the indoor air mixing ratio during the first air mixing in the solar greenhouse heating system according to the collected temperature and relative humidity in the greenhouse;

[0027] The MPC controller is used to obtain the total air volume required to be heated in the solar greenhouse heating system based on the operating temperature of the solar heat storage and heat exchange subsystem, the outlet temperature of the soil-air heat exchanger subsystem, the ambient dry-bulb temperature outside the solar greenhouse body, the solar radiation intensity and the ambient wind speed.

[0028] The present invention also provides a working method of a solar greenhouse heating system, which includes five working modes: soil-air heat exchange heating mode, single-sided heat storage heat exchange heating mode, soil-air heat exchange heating and solar heat storage heat exchange combined heating mode, double-sided heat storage heat exchange heating mode and electric heating heating mode.

[0029] Furthermore, according to the heat supply comparison result, the process of obtaining the heating mode selection result of the solar greenhouse heating system is specifically as follows:

[0030] If the nighttime demand load of the solar greenhouse body ,satisfy When , the soil-air heat exchange heating mode is selected;

[0031] If the nighttime demand load of the solar greenhouse body ,satisfy When , the single-side heat storage and heat exchange heating mode is selected;

[0032] If the nighttime demand load of the solar greenhouse body ,satisfy When the heat is high, the combined heating mode of soil-air heat exchange and solar heat storage and heat exchange is selected;

[0033] If the nighttime demand load of the solar greenhouse body ,satisfy When , the double-side heat storage and heat exchange heating mode is selected;

[0034] If the nighttime demand load of the solar greenhouse body ,satisfy When , select the electric heating mode.

[0035] Furthermore, the nighttime demand load of the solar greenhouse body , specifically:

[0036]

[0037] in, is the heat transfer coefficient of the solar greenhouse itself, The coverage area of ​​the greenhouse insulation layer; The temperature of the greenhouse insulation layer; is the external ambient temperature;

[0038] The designed heating capacity under the preset soil-air heat exchange heating mode , specifically:

[0039]

[0040] in, is the air density; The number of air heat exchanges; is the volume of air in the greenhouse; is the heat capacity of air; is the outlet temperature of the soil-air heat exchange subsystem; is the air temperature inside the greenhouse;

[0041] The designed heat supply in the preset single-side heat storage and heat exchange heating mode , specifically:

[0042]

[0043] wherein, is the outlet temperature of the solar heat storage and heat exchange subsystem;

[0044] the preset design heat supply in the soil-air heat exchange heat supply and solar heat storage and heat exchange combined heat supply mode , specifically:

[0045]

[0046] wherein, is the preset design heat supply in the soil-air heat exchange heat supply mode; is the preset design heat supply in the single-side heat storage and heat exchange heat supply mode.

[0047] Compared with the prior art, the beneficial effects of the present application are:

[0048] The sunlight greenhouse heat supply system and working method provided by the present application, by setting two solar heat storage and heat exchange subsystems and a soil-air heat exchange subsystem, preheats the air entering the soil-air heat exchange subsystem by using the solar heat storage and heat exchange subsystem, the preheated air enters the air supply dry pipe in the soil-air heat exchange subsystem for first air mixing, the first air mixing air exchanges heat with the geothermal energy of the soil when flowing through the soil heat exchange pipeline in the soil-air heat exchange subsystem, and the air after the geothermal energy heat exchange enters the sunlight greenhouse body through the air supply dry pipe in the soil-air heat exchange subsystem for second air mixing, so as to realize the regulation of the hot and humid environment in the sunlight greenhouse; in the present application, the hot and humid environment in the sunlight greenhouse is flexibly regulated by using the solar heat storage and heat exchange subsystem and the soil-air heat exchanger, renewable geothermal energy and solar energy are used for greenhouse heat supply, no fossil energy is consumed, various weather conditions can be effectively coped with, the stability and self-regulation ability of the greenhouse temperature are greatly improved, environmental pollution is greatly reduced, and the yield of the planting function is ensured; secondly, the electric heater is set to supply heat for the sunlight greenhouse, which can effectively cope with extreme weather changes and ensure the reliable operation of the sunlight greenhouse.

[0049] Further, the water pool heat storage energy storage technology is used in the solar heat storage and heat exchange subsystem to heat the air, which has the advantages of low energy storage cost, high reliability and system safety.

[0050] Further, by setting the soil-air heat exchange heat supply mode, the single-side heat storage and heat exchange heat supply mode, the soil-air heat exchange heat supply and solar heat storage and heat exchange combined heat supply mode, the double-side heat storage and heat exchange heat supply mode and the electric heating heat supply mode, different heat supply modes can be selected for heat supply according to the night demand load of the sunlight greenhouse body, the heat supply efficiency and energy saving performance of the heat supply system are effectively improved, and the timeliness and accuracy of the greenhouse environment control and regulation are ensured.

[0051] Furthermore, the PID-MPC combined control strategy is used to adjust the valve opening, which can achieve accurate and reliable greenhouse environment regulation and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the overall structure of the solar greenhouse heating system of the present invention;

[0053] Figure 2 This is a schematic structural diagram of the solar heat storage and heat exchange device in the solar greenhouse heating system of the present invention;

[0054] Figure 3 This is a schematic structural diagram of the heat storage and heat exchange water tank in the solar greenhouse heating system of the present invention;

[0055] Figure 4 This is a schematic diagram of the internal structure of the heat collector unit in the solar greenhouse heating system of the present invention;

[0056] Figure 5 This is a schematic diagram of the solar greenhouse heating system of the present invention;

[0057] Figure 6 This is a flow chart for selecting a heating mode for the solar greenhouse heating system of the present invention;

[0058] Figure 7 This is a schematic diagram of the temperature and power zoning of the heating system of the solar greenhouse in the present invention;

[0059] Figure 8 This is a schematic diagram of the soil-air heat exchange heating mode in the present invention;

[0060] Figure 9 This is a schematic diagram of the single-side heat storage and heat exchange heating mode in the present invention;

[0061] Figure 10 This is a schematic diagram of the combined heating mode of soil-air heat exchange and solar thermal storage and heat exchange in the present invention;

[0062] Figure 11 This is a schematic diagram of the double-sided heat storage and heat exchange heating mode in the present invention;

[0063] Figure 12 This is a schematic diagram of the working principle of the load calculation module in the present invention.

[0064] Wherein, 100 sunlight greenhouse body, 200 greenhouse heat preservation layer; 1 solar heat collector, 2 water supply pipeline, 3 return water pipeline, 4 heat storage and heat exchange pool, 5 tube bundle heat exchanger, 6 submersible pump; 7 soil heat exchange pipeline, 8 air supply main pipe, 9 air supply pipe in greenhouse, 10 air supply pipe outside greenhouse, 11 air supply main pipe, 12 air supply branch pipe, 13 axial flow fan, 14 electric heater; 15 heat collector temperature collector, 16 pool temperature collector, 17 greenhouse temperature collector, 18 soil temperature sensor; 19 first electric valve, 20 second electric valve, 21 third electric valve, 22 fourth electric valve, 23 fifth electric valve, 24 sixth electric valve, 25 seventh electric valve, 26 eighth electric valve; 101 heat collector unit water supply branch pipe, 102 heat collector unit return water branch pipe; 401 water supply pipe interface, 402 return water pipe interface, 403 pool maintenance opening, 404 multifunctional hole. DETAILED DESCRIPTION

[0065] In order to make the technical problems solved by the present application, the technical solutions and beneficial effects clearer, the following specific embodiments are used to further illustrate the present application. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0066] As shown in the accompanying drawings Figure 1-4 The present application provides a sunlight greenhouse heating system, which comprises two solar heat storage and heat exchange subsystems, a soil-air heat exchange subsystem, two electric heaters 14, a control subsystem, a first electric valve 19, a second electric valve 20, a third electric valve 21, a fourth electric valve 22, a fifth electric valve 23, a sixth electric valve 24, a seventh electric valve 25 and an eighth electric valve 26.

[0067] The two solar heat storage and heat exchange subsystems are located at two ends of the soil-air heat exchange subsystem respectively, the inlets of the solar heat storage and heat exchange subsystems are communicated with the atmosphere outside the sunlight greenhouse body 100, and the outlets of the solar heat storage and heat exchange subsystems are connected with the air supply main pipe in the soil-air heat exchange subsystem; wherein the solar heat storage and heat exchange subsystems are used for heating the air outside the greenhouse by using solar energy, and conveying the heated air into the soil-air heat exchange subsystem.

[0068] The two solar heat storage and heat exchange subsystems are the same in structure, and both adopt a solar heat storage and heat exchange device; the solar heat storage and heat exchange device comprises a solar heat collector 1, a water supply pipeline 2, a return water pipeline 3, a heat storage and heat exchange pool 4, a tube bundle heat exchanger 5 and a submersible pump 6; wherein the solar heat collector 1, the water supply pipeline 2, the return water pipeline 3, the heat storage and heat exchange pool 4, the tube bundle heat exchanger 5 and the submersible pump 6 are connected to form a water heat exchange circulation loop.

[0069] Specifically, the solar heat collector 1 is arranged at the top end of the rear wall of the sunlight greenhouse body 100, the top of the sunlight greenhouse body 100 is provided with a greenhouse heat preservation layer 200; the water supply pipeline 2 and the water return pipeline 3 are arranged in the sunlight greenhouse body 100, and the water supply pipeline 2 and the water return pipeline 3 are laid along the rear wall of the sunlight greenhouse body 100; the heat storage and heat exchange pool 4 is arranged at the end of the soil-air heat exchange subsystem and is placed underground at both ends of the sunlight greenhouse body 100; the inlet end of the water supply pipeline 2 is connected with the water outlet of the heat storage and heat exchange pool 4, and the outlet end of the water supply pipeline 2 is connected with the cold water inlet of the solar heat collector 1; the inlet end of the water return pipeline 3 is connected with the hot water outlet of the solar heat collector 1, and the outlet end of the water return pipeline 3 is connected with the water inlet of the heat storage and heat exchange pool 4; the tube bundle heat exchanger 5 is arranged in the heat storage and heat exchange pool 4, the air inlet of the tube bundle heat exchanger 5 is connected with the atmosphere outside the sunlight greenhouse body 100, and the air outlet of the tube bundle heat exchanger 5 is connected with the third air inlet on the air supply dry pipe in the soil-air heat exchange subsystem; the submersible pump 6 is arranged in the heat storage and heat exchange pool 4 and is placed at the water outlet of the heat storage and heat exchange pool 4; wherein the water outlet of the submersible pump 6 is connected with the inlet end of the water supply pipeline 2.

[0070] In the application, the solar heat collector 1 comprises a plurality of heat collector units arranged in parallel, each heat collector unit is made of a hollow PC plate; wherein the outer surface of the PC plate is coated with black heat absorbing material; the cold water inlet of each heat collector unit is connected with the outlet end of the water supply pipeline 2 through a heat collector unit water supply branch pipe 101, and the hot water outlet of each heat collector unit is connected with the inlet end of the water return pipeline 3 through a heat collector unit water return branch pipe 102; the inside of each heat collector unit is provided with a Z-shaped channel, the Z-shaped channel is used for water flow and can exchange heat with solar energy.

[0071] It should be noted that the area requirement of each heat collector unit is affected by multiple factors, including the solar energy enrichment degree of the region, the heat collector manufacturing process, the heat exchanger performance, etc., and generally 1 square meter of heat collecting area can produce 90kg of hot water of 45℃-65℃ per day under general illumination; when calculating the area of the solar heat collector according to the heating demand of the designed greenhouse, the actual illumination conditions of the local area are considered , the design illumination conditions of the heat collector , the daily average minimum temperature of the heat storage pool , the comprehensive coefficient of the heat collector use environment and the heat exchanger performance , the heat storage water volume of the heat collector , and the night demand heat of the greenhouse ; wherein the heat collector area calculation formula is as follows:

[0072]

[0073]

[0074] wherein, is the collector area.

[0075] The heat storage and exchange pool 4 comprises, from outside to inside, a reinforced concrete layer, an insulation layer and an anti-seepage layer; the top of the heat storage and exchange pool 4 is provided with a water supply pipe interface 401, a return water pipe interface 402, a pool maintenance opening 403 and a multifunctional hole 404; the water supply pipe interface 401 serves as the water outlet of the heat storage and exchange pool 4 and is used for connecting the water supply pipe 2 with the heat storage and exchange pool 4; the return water pipe interface 402 serves as the water inlet of the heat storage and exchange pool 4 and is used for connecting the return water pipe 3 with the heat storage and exchange pool 4; the pool maintenance opening 403 is used for the entry of equipment or personnel during pool maintenance; the multifunctional hole 404 is used as a temperature measurement, water replenishment, water drainage and sewage drainage channel; wherein the hole opening parts of the water supply pipe interface 401, the return water pipe interface 402, the pool maintenance opening 403 and the multifunctional hole 404 are connected with the insulation layer in a sealed and heat-insulated manner.

[0076] Preferably, the thickness of the reinforced concrete layer is 250-300 mm; the insulation layer adopts hard polyurethane foam plastic plate, the thickness of the hard insulation layer of the pool wall and pool bottom is 100-150 mm, and the thickness of the top of the insulation layer is 150-200 mm; the anti-seepage layer adopts high-temperature-resistant high-density polyethylene anti-seepage film; the size of the maintenance opening is 600 mm x 600 mm, and the periphery of the inspection opening and the top of the heat storage and exchange pool insulation layer are connected in a sealed and heat-insulated manner.

[0077] The soil-air heat exchange subsystem is arranged inside the sunlight greenhouse body 100 and along the long axis direction of the sunlight greenhouse body 100; the soil-air heat exchange subsystem comprises soil heat exchange pipelines 7, two air supply main pipes 8, two air supply pipes inside the greenhouse 9, two air supply pipes outside the greenhouse 10, an air supply main pipe 11, a plurality of air supply branch pipes 12 and two axial flow fans 13.

[0078] Specifically, the soil heat exchange pipe 7 is buried underground inside the solar greenhouse body 100 and is placed 1-2m underground; wherein, the soil heat exchange pipe 7 is arranged along the long axis direction of the solar greenhouse body 100, and serves as a heat exchange space between the air inside it and the soil; the two air supply dry pipes 8 are respectively arranged at both ends of the soil heat exchange pipe 7, and each of the air supply dry pipes 8 is provided with a first air inlet, a second air inlet, a third air inlet and an air supply port; wherein, the first air inlet is connected to the air inside the solar greenhouse body 100, and the second air inlet is connected to the atmosphere outside the solar greenhouse body 100; the third air inlet on one of the air supply dry pipes is connected to the outlet of one of the solar heat storage and heat exchange subsystems, and the third air inlet on the other air supply dry pipe is connected to the outlet of another solar heat storage and heat exchange subsystem.

[0079] One of the greenhouse air supply pipes 9 and one of the greenhouse air supply pipes 10 are arranged on both sides of one of the air supply main pipes 8, and the other greenhouse air supply pipe 9 and the other greenhouse air supply pipe 10 are arranged on both sides of the other air supply main pipe 8.

[0080] Take the structure of the greenhouse air supply pipe 9 and the greenhouse air supply pipe 10 provided on both sides of one of the air supply main pipes 8 as an example:

[0081] The inlet end of the greenhouse air supply pipe 9 extends to above the internal ground of the solar greenhouse body 100 and is connected to the air inside the solar greenhouse body 100, and the outlet end of the greenhouse air supply pipe 9 is connected to the first air inlet of the air supply main pipe 8; the inlet end of the greenhouse external air supply pipe 10 extends to the outside of the solar greenhouse body 100 and is connected to the atmosphere outside the solar greenhouse body 100; the outlet end of the greenhouse external air supply pipe 10 is designed in two ways, one of which is connected to the second air inlet of the air supply main pipe 8, and the other is connected to the air inlet of the tube bundle heat exchanger 5; wherein, filtering structures are respectively provided at the inlet ends of the greenhouse internal air supply pipe 9 and the greenhouse external air supply pipe 10 to filter impurities in the air.

[0082] It should be noted that the structures of the greenhouse air supply pipe 9 and the greenhouse air supply pipe 10 arranged on both sides of the other air supply main pipe 8 are similar to the above-mentioned structures and will not be repeated here.

[0083] It should be noted that when the double-sided heat storage heat exchange heating mode and the electric heating mode are selected, the air inlet of the tube bundle heat exchanger 5 is connected to the second air inlet of the air supply dry pipe 8 through two outlet ends of the greenhouse external air supply pipe 10, so that the indoor air flow is heated by the tube bundle heat exchanger 5 and then enters the air supply dry pipe 8.

[0084] The air supply main pipe 11 is arranged above the internal ground of the sunlight greenhouse body 100, and the two ends of the air supply main pipe 11 are connected to the air supply ports of the two air supply main pipes 8 respectively; wherein the air supply main pipe 11 is used to transport the air after heat exchange with the soil to the inside of the sunlight greenhouse body 100; a plurality of air supply holes are arranged on the air supply main pipe 11, and the plurality of air supply holes are uniformly distributed along the axis of the air supply main pipe 11; a plurality of air supply branch pipes 12 are arranged at the plurality of air supply holes correspondingly; wherein one end of the air supply branch pipe 12 is connected to the air supply hole, and the other end of the air supply branch pipe 12 is in communication with the air in the sunlight greenhouse body 100.

[0085] Two axial flow fans 13 are arranged in the two air supply main pipes 8 respectively, and the axial flow fan 13 is used to provide air flow power; wherein the axial flow fan 13 is arranged between the first air inlet and the third air inlet of the air supply main pipe 8; two electric heaters 14 are arranged at the two ends of the air supply main pipe 11 respectively and close to one side of the two air supply main pipes 8 respectively; wherein the electric heater 14 is used to electrically heat the air flow entering the air supply main pipe 11; the electric heater 14 is arranged on the air supply main pipe 11, and the air supply main pipe 11 has the functions of high temperature resistance and detachability; the electric heater 14 is connected in series with the main body of the air supply main pipe 11, and the connection part is sealed.

[0086] It should be noted that under the premise that the heat supply system is in normal operation, the heat storage and heat exchange pool 4 and the soil-air heat exchange subsystem can meet the daily heat load demand of the sunlight greenhouse body, and the heat provided by the heat storage and heat exchange pool is greater than the heat provided by the soil-air heat exchange subsystem.

[0087] As shown in the accompanying drawings, Figure 5 The first electric valve 19 is arranged at the inlet of the first solar heat storage and heat exchange subsystem; the second electric valve 20 is arranged on the first air supply main pipe and is arranged between the first air inlet and the second air inlet of the first air supply main pipe; the third electric valve 21 is arranged at the outlet of the first solar heat storage and heat exchange subsystem; the fourth electric valve 22 is arranged on the air supply main pipe 11 and is arranged close to one end of the first air supply main pipe; the fifth electric valve 23 is arranged on the air supply main pipe 11 and is arranged close to one end of the second air supply main pipe; the sixth electric valve 24 is arranged on the second air supply main pipe and is arranged between the first air inlet and the second air inlet of the second air supply main pipe; the seventh electric valve 25 is arranged at the inlet of the second solar heat storage and heat exchange subsystem; and the eighth electric valve 26 is arranged at the outlet of the second solar heat storage and heat exchange subsystem.

[0088] The control subsystem comprises a greenhouse information acquisition module, an environment data acquisition module, a thermal insulation layer state information acquisition module, a load calculation module, an opening degree adjustment module, a water pump control module and a mode selection module; the greenhouse information acquisition module is used for acquiring the temperature in the greenhouse, the relative humidity in the greenhouse, the working temperature of the solar heat storage and exchange subsystem and the outlet temperature of the soil-air heat exchange subsystem; the environment data acquisition module is used for acquiring the ambient dry bulb temperature outside the solar greenhouse body 100, the solar radiation intensity and the ambient wind speed; the thermal insulation layer state information acquisition module is used for acquiring the opening state information of the greenhouse thermal insulation layer 200 at the current time; the load calculation module is used for calculating the total amount of indoor gas and the total amount of outdoor gas in the solar greenhouse heating system during the first air mixing according to the acquired temperature in the greenhouse, the relative humidity in the greenhouse, the working temperature of the solar heat storage and exchange subsystem, the outlet temperature of the soil-air heat exchanger subsystem, the ambient dry bulb temperature outside the solar greenhouse body 100, the solar radiation intensity and the ambient wind speed; the opening degree adjustment module is used for generating and sending the opening degree adjustment instruction of the electric valve to the first electric valve 19, the second electric valve 20, the third electric valve 21, the fourth electric valve 22, the fifth electric valve 23, the sixth electric valve 24, the seventh electric valve 25 and the eighth electric valve 26 according to the total amount of indoor gas and the total amount of outdoor gas in the solar greenhouse heating system during the first air mixing; the water pump control module is used for generating and sending the water pump adjustment instruction to the submersible pump 6 according to the working temperature of the solar heat storage and exchange subsystem, the ambient dry bulb temperature outside the solar greenhouse body 100, the solar radiation intensity and the ambient wind speed; wherein the working temperature of the solar heat storage and exchange subsystem comprises the inlet temperature and the outlet temperature of the solar heat collector 1 and the temperature of the heat storage and exchange pool 4; the mode selection module is used for determining the working mode of the solar greenhouse heating system according to the temperature in the greenhouse and the opening state information of the greenhouse thermal insulation layer 200 at the current time.

[0089] Specifically, the greenhouse information acquisition module comprises a heat collector temperature collector 15, a pool temperature collector 16, a greenhouse temperature collector 17, a soil temperature collector 18, a greenhouse relative humidity collector and an outlet temperature sensor; the heat collector temperature collector 15 is used for collecting the inlet temperature and the outlet temperature of the solar heat collector 1, the pool temperature collector 16 is used for collecting the temperature of the heat storage and exchange pool 4, the greenhouse temperature collector 17 is used for collecting the temperature in the solar greenhouse body 100, the soil temperature collector 18 is used for collecting the soil temperature in the solar greenhouse body 100, the greenhouse relative humidity collector is used for collecting the relative humidity in the solar greenhouse body 100, and the outlet temperature sensor is used for collecting the outlet temperature of the soil-air heat exchange subsystem.

[0090] In the present application, the sunlight greenhouse heating system comprises five working modes, specifically: soil-air heat exchange heating mode, single-side heat storage heat exchange heating mode, soil-air heat exchange heating and solar heat storage heat exchange combined heating mode, double-side heat storage heat exchange heating mode and electric heating heating mode; wherein, the heating mode selection process of the sunlight greenhouse heating system is as follows:

[0091] determining the night demand load of the sunlight greenhouse body 100 , comparing the night demand load of the sunlight greenhouse body 100 with the preset design heating capacity in the soil-air heat exchange heating mode , the preset design heating capacity in the single-side heat storage heat exchange heating mode and the preset design heating capacity in the soil-air heat exchange heating and solar heat storage heat exchange combined heating mode ; according to the heating capacity comparison result, the heating mode selection result of the sunlight greenhouse heating system is obtained.

[0092] the night demand load of the sunlight greenhouse body (100) , specifically:

[0093]

[0094]

[0095]

[0096] wherein, is the heat transfer coefficient of the sunlight greenhouse body, is the covering area of the greenhouse heat preservation layer; is the temperature of the greenhouse heat preservation layer; is the ambient temperature; is the convective heat transfer coefficient in the greenhouse, which is 11 kJ / (m -2 k -1 h -1 ); is the temperature of the greenhouse heat preservation layer; is the thickness of the greenhouse heat preservation layer; is the thermal conductivity of the greenhouse heat preservation layer; is the environmental wind speed; is the characteristic size parameter of the greenhouse.

[0097] the preset design heating capacity in the soil-air heat exchange heating mode , specifically:

[0098]

[0099] wherein, is the air density; The number of air heat exchanges; is the volume of air in the greenhouse; is the heat capacity of air; is the outlet temperature of the soil-air heat exchange subsystem, which is related to the air flow rate and burial depth and is taken as 16-20℃; is the air temperature inside the greenhouse.

[0100] The designed heat supply in the preset single-side heat storage and heat exchange heating mode , specifically:

[0101]

[0102] in, is the outlet temperature of the solar thermal storage and heat exchange subsystem, which is related to the structure of the tube bundle heat exchanger and the air flow rate; the temperature difference between the outlet temperature of the solar thermal storage and heat exchange subsystem and the liquid temperature in the thermal storage and heat exchange water pool is 20-30℃. The temperature of the thermal storage and heat exchange water pool is related to the local solar radiation and the demand of greenhouse crops. The recommended temperature setting range of the thermal storage and heat exchange water pool is 60-80℃.

[0103] The designed heating capacity under the preset soil-air heat exchange and solar heat storage heat exchange combined heating mode , specifically:

[0104]

[0105] in, The design heating capacity under the preset soil-air heat exchange heating mode; It is the designed heat supply under the preset single-side heat storage and heat exchange heating mode.

[0106] Working mode selection principle:

[0107] As attached Figure 6 As shown, the heating mode selection process of the solar greenhouse heating system of the present invention specifically includes the following steps:

[0108] Step 101: Acquire the temperature in the greenhouse at the current moment, the opening status information of the greenhouse insulation layer 200 at the current moment, and call the temperature history data in the greenhouse.

[0109] Step 102: determine a temperature prediction model based on the opening state of the greenhouse insulation layer 200 at the current moment; wherein the temperature prediction model is used to calculate the temperature in the greenhouse at the next moment by using the temperature in the greenhouse at the current moment and the temperature history data in the greenhouse.

[0110] The determination process of the temperature prediction model is as follows:

[0111] (a) When the greenhouse insulation layer 200 is on and the heating system is not running, the temperature inside the greenhouse is less affected by the external environment, and the heat loss is linearly related to time. The interpolation method is used to predict the temperature inside the greenhouse at the next moment. At this time, the temperature prediction model is specifically as follows:

[0112]

[0113] in, is the temperature in the greenhouse at the next moment; is the temperature in the greenhouse at the current moment; is the temperature in the greenhouse at the previous moment.

[0114] (b) When the greenhouse insulation layer 200 is turned on and the heating system is running, the temperature inside the greenhouse is determined by the heat transfer process with the environment and the heating process of the heating system. At this time, based on the opening state information of the greenhouse insulation layer 200, it is judged whether the current greenhouse state has a relatively stable state of the insulation layer. Assuming that the greenhouse heating system is running normally, the greenhouse state is always as shown in the attached figure. Figure 7 In the B area; in a greenhouse heating mode, when the greenhouse state is as follows Figure 7 If the temperature in the B3 area is still slowly decreasing, set the gain coefficient in the temperature prediction model. , Less than 1; that is, the temperature prediction model is specifically:

[0115]

[0116] in, is the gain coefficient, Less than 1.

[0117] When the greenhouse is in the following state Figure 7 If the temperature in the B1 area is still increasing slowly, set the gain coefficient in the temperature prediction model. ; That is, the temperature prediction model is specifically:

[0118]

[0119] in, is the gain coefficient, Less than 1.

[0120] It should be noted that the gain coefficient The value is affected by the temperature in the greenhouse and the outlet temperature of the heating system; among them, the gain coefficient The calculation process is as follows:

[0121]

[0122] in, is the outlet temperature of the heating system; is the temperature in the greenhouse; is the external ambient temperature; The lowest local ambient temperature.

[0123] (c) When the greenhouse insulation layer 200 is closed, the temperature inside the greenhouse is significantly affected by the external environment, and the heat loss has a nonlinear relationship with time. At this time, the temperature prediction model is specifically as follows:

[0124]

[0125] in, is the current time; and is a constant coefficient, which is calculated from the current temperature and the temperature value at the previous moment.

[0126] Step 103: Determine the nighttime load requirement of the greenhouse body 100. , the nighttime demand load of the solar greenhouse body 100 Compared with the design heating capacity under the preset soil-air heat exchange heating mode , Designed heating capacity under the preset single-side heat storage and heat exchange heating mode And the design heating capacity under the preset soil-air heat exchange heating and solar heat storage heat exchange combined heating mode Compare; according to the heat supply comparison result, obtain the heating mode selection result of the solar greenhouse heating system.

[0127] The following is a detailed description of the working status of the above five working modes:

[0128] As attached Figure 8 As shown, if the nighttime demand load of the solar greenhouse body 100 ,satisfy When , the soil-air heat exchange heating mode is selected, which is recorded as mode 1; specifically, the first axial flow fan a is started, the first electric valve 19, the third electric valve 21, the fourth electric valve 22, the seventh electric valve 25 and the eighth electric valve 26 are closed, the second electric valve 20, the fifth electric valve 23 and the sixth electric valve 24 are opened, and the inlet II of the greenhouse external air supply pipe and the inlet IV of the greenhouse internal air supply pipe are closed; the inlet of the greenhouse external air supply pipe; the opening of the electric valve at the inlet I of the greenhouse external air supply pipe and the inlet III of the greenhouse internal air supply pipe is adjusted according to the indoor and outdoor air mixing ratio; the indoor and outdoor gases are then mixed for the first time in the air supply main pipe 8, and the mixed air is heated and heated through the soil heat exchange pipe 7, and the hot air flows into the greenhouse from the air supply main pipe 11 through the air supply branch pipe 12, and is mixed for the second time with the low-temperature gas in the greenhouse until the feedback value of the temperature in the greenhouse reaches the temperature control set value; wherein, the gas flow route is as shown in the attached figure Figure 8 As shown by the dotted line in .

[0129] As attached Figure 9 As shown, if the nighttime demand load of the solar greenhouse body 100 ,satisfy When the soil-air heat exchanger is insufficient to meet the temperature regulation requirements, a single-side heat storage heat exchange heating mode is selected, which is recorded as mode 2. Specifically, the first axial flow fan a and the second axial flow fan b are started, the second electric valve 20, the fifth electric valve 23, the seventh electric valve 25 and the eighth electric valve 26 are closed, the first electric valve 19, the third electric valve 21, the fourth electric valve 22 and the sixth electric valve 24 are opened, and the inlet IV of the greenhouse air supply pipe is closed. The openings of the electric valves at the inlet II of the greenhouse air supply pipe and the inlet III of the greenhouse air supply pipe are adjusted according to the indoor and outdoor air mixing ratio. The outdoor air is first preheated by the soil heat exchanger pipe 7 and then mixed with the low-temperature greenhouse gas entering through the inlet III of the greenhouse air supply pipe. The mixed air is heated by the tube bundle heat exchanger 5 in the heat storage water tank 4. The hot air flows into the greenhouse from the air supply main pipe 11 through the air supply branch pipe 12 and is mixed with the low-temperature greenhouse gas for a second time until the temperature feedback value in the greenhouse reaches the temperature control set value. The gas flow route is shown in the attached figure. Figure 9 As shown by the dotted line in the figure; in order to ensure the uniformity of the overall air supply to the greenhouse, a valve can be set at the air outlet of the air supply branch pipe to adjust the air outlet flow.

[0130] As attached Figure 10 As shown, if the nighttime demand load of the solar greenhouse body 100 ,satisfy When the single-side heat storage and heat exchange water pool heating mode is insufficient to meet the temperature regulation requirements, the soil-air heat exchange heating and solar heat storage and heat exchange combined heating mode is selected, which is recorded as mode 3; specifically, the first axial flow fan a is started, the first electric valve 19, the third electric valve 21, the fourth electric valve 22 and the sixth electric valve 24 are closed, the second electric valve 20, the fifth electric valve 23, the seventh electric valve 25 and the eighth electric valve 26 are opened, and the inlet II of the greenhouse external air supply pipe and the inlet IV of the greenhouse internal air supply pipe are closed; according to the indoor and outdoor The air mixing ratio adjusts the opening of the electric valves at the inlet I of the greenhouse air supply pipe and the inlet III of the greenhouse air supply pipe; the indoor and outdoor air are mixed for the first time in the air supply main pipe, and then preheated by the soil through the soil heat exchanger pipe 7. The preheated air is heated by the tube bundle heat exchanger 5 in the heat storage and heat exchange pool 4. The hot air flows into the greenhouse through the air supply main pipe 11 and the air supply branch pipe 12, and is mixed with the low-temperature gas in the greenhouse for the second time until the temperature feedback value in the greenhouse reaches the temperature control set value; the gas flow route is shown in the attached figure. Figure 10 As shown by the dotted line in .

[0131] As attached Figure 11 As shown, if the nighttime demand load of the solar greenhouse body 100 ,satisfy When the combined heating mode of soil-air heat exchange and solar heat storage and heat exchange is insufficient to meet the temperature regulation demand, the double-side heat storage and heat exchange heating mode is selected, which is recorded as mode 4. In this mode, the greenhouse load is large and the geothermal energy is effectively utilized, and the introduction of outdoor cold air to increase the load demand is no longer required. Specifically, the first axial flow fan a is started, the second electric valve 20 and the sixth electric valve 24 are closed; the first electric valve 19, the third electric valve 21, the fifth electric valve 23, the seventh electric valve 25 and the eighth electric valve 26 are opened, and the inlet I of the greenhouse external air supply pipe and the inlet II of the greenhouse external air supply pipe are closed; the low-temperature gas in the greenhouse passes through the inlet III of the greenhouse internal air supply pipe and the inlet IV of the greenhouse internal air supply pipe, and is heated by the tube bundle heat exchanger 5 in the heat storage and heat exchange water tank 4. The hot air flows into the greenhouse from the air supply main pipe 11 through the air supply branch pipe 12 and mixes with the low-temperature gas in the greenhouse until the temperature feedback value in the greenhouse reaches the temperature control set value. The gas flow route is shown in the attached figure. Figure 11 As shown by the dotted line in .

[0132] It should be noted that since the two solar thermal storage and heat exchange subsystems are symmetrically distributed, when the operating conditions of the axial flow fans on both sides are the same, the continuity equation shows that the flow velocity at the symmetrical position of the pipeline is the same, and the Bernoulli equation shows that the pressure head is also the same. Therefore, the air flow follows the preset path, and there is no need to install an electric valve in the soil heat exchanger pipeline to control the airflow path.

[0133] If the nighttime demand load of the solar greenhouse body 100 ,satisfy When, that is, when, due to the influence of external weather, the heat storage and heat exchange water tank 4 fails to store enough heat to meet the temperature regulation demand of the greenhouse, or the regulation method of the heat storage and heat exchange water tank 4 is insufficient to meet the temperature regulation demand, the auxiliary electric heating mode is turned on at this time, and the electric heating mode is selected, which is recorded as mode five; specifically, the first axial flow fan a is started, the electric heater 14 is started, the first electric valve 19, the third electric valve 21, the fourth electric valve 22 and the sixth electric valve 24 are closed, the second electric valve 20, the fifth electric valve 23, the seventh electric valve 25 and the eighth electric valve 26 are opened, and the air supply pipe outside the greenhouse is closed. Entrance II and entrance IV of the air supply pipe in the greenhouse; the opening of the electric valve at the entrance I of the air supply pipe outside the greenhouse and the entrance III of the air supply pipe in the greenhouse is adjusted according to the mixing ratio of indoor and outdoor air; the first mixing is carried out in the gas supply air main pipe, and the mixed air is preheated and heated by the soil heat exchange pipe 7, and then the second heating is achieved by the tube bundle heat exchanger 5 in the heat storage and heat exchange pool 4. Finally, the hot air flows through the air supply main pipe 11 and is heated again by the electric heater 14 through convection heat exchange; the heated air flows into the greenhouse through the air supply branch pipe 12 and is mixed with the low-temperature gas in the greenhouse for the second time until the temperature feedback value in the greenhouse reaches the temperature control set value.

[0134] In the present invention, the indoor and outdoor air mixing ratio is determined based on the total amount of indoor gas and the total amount of outdoor gas during the first air mixing in the solar greenhouse heating system calculated by the load calculation module; wherein, the load calculation module adopts a PID-MPC joint control strategy, specifically including a PID controller and an MPC controller; wherein, the PID controller is used to determine the indoor air mixing ratio during the first air mixing in the solar greenhouse heating system based on the collected temperature in the greenhouse and the relative humidity in the greenhouse; the MPC controller is used to obtain the total air volume that needs to be heated in the solar greenhouse heating system based on the operating temperature of the solar heat storage and heat exchange subsystem, the outlet temperature of the soil-air heat exchanger subsystem, the ambient dry bulb temperature outside the solar greenhouse body 100, the solar light intensity and the ambient wind speed.

[0135] As attached Figure 12 As shown, the working principle of the load calculation module is as follows:

[0136] After determining the operating mode, the greenhouse thermal and humid environment is controlled by combining proportional-integral-derivative control (PID) with model predictive control (MPC) to implement a secondary air mixing control strategy. The indoor and outdoor air are mixed for the first time and then heated by the determined heating mode, and the heated air is mixed with the air in the greenhouse for a second time.

[0137] When using a PID controller to solve the mixed value in the greenhouse thermal and humid environment control, only a single parameter can be used as the control target in each calculation step, that is, the control object is temperature or relative humidity; therefore, it is necessary to design corresponding operation rules for the controller so that it can reasonably select the control object in the greenhouse thermal and humid environment control to ensure that the control effect meets the design requirements.

[0138] In the present invention, dynamic selection of the control object is achieved through preset operation rules based on the actual situation in the greenhouse; in the process of selecting the control object, different gain coefficients are set according to the different emphases on greenhouse temperature and greenhouse humidity, and a certain parameter is selected as the control object by calculating and comparing the size of the influence values ​​of different parameters.

[0139] Among them, the dynamic selection of the control object is realized through the preset operation rules, as follows: design ideal reference values ​​for the control objects respectively; in the present invention, the reference temperature of the greenhouse is set to 15℃ and the reference relative humidity is set to 70%; calculate the deviation values ​​of different control objects; in the present invention, the value ranges of temperature and relative humidity are [13℃, 17℃] and [50%, 80%] respectively, then the deviation values ​​of temperature T and relative humidity RH as control objects are ∆T =17- T 、 ∆RH = RH -50; normalize the deviation value; since the relative humidity fluctuation range is much larger than the temperature fluctuation range, in order to facilitate the comparison of the influence values ​​of different parameters, the deviation value of different parameters is divided by the design range value to achieve the normalization of the deviation value of different parameters. y ∆T =(17- T ) / 4、 y ∆RH =(RH-50) / 30; set the gain coefficient for the normalized results of different parameters a 1. b 1; According to the importance of different control objects, set the corresponding gain coefficient for them. y` ∆T = a 1·y ∆ 、 y` ∆RH = b 1. y ∆RH ; Select the control object; calculate the impact value of different control objects y` ∆T ,y` ∆RH Compare and select the larger value as the control object of the PID controller

[0140] In the application, the control parameter object is determined by using a preset operation rule, the PID controller outputs a mixing ratio according to the deviation of the control object parameter and the design reference value, and then performs numerical calculation with the total heating air volume output by the MPC controller to respectively calculate the total amount of indoor gas and outdoor gas; the opening degree of the electric valve is adjusted according to the calculation result, and the corresponding amount of indoor and outdoor air is mixed, the mixed air is transported to the greenhouse after being heated and dehumidified by the solar auxiliary soil air heat exchanger system for secondary mixing until the hot and humid environment of the greenhouse meets the design requirements.

[0141] In the application, the operation process of the solar heat storage and exchange subsystem is specifically as follows: in the heat storage stage, when the temperature of the liquid in the heat storage and exchange pool 4 does not reach the preset value, the submersible pump 6 is started to make the liquid in the heat storage and exchange pool 4 flow into the solar heat collector 1 to absorb the sunlight heat through heat conduction between the solar heat collector 1 and the liquid; the temperature of the solar heat collector 1 is increased, the submersible pump 6 is started again to make the high-temperature water flow into the heat storage and exchange pool 4, and the low-temperature water in the heat storage and exchange pool 4 flows into the solar heat collector 1, and the operation is repeated until the sunlight is insufficient to heat the liquid in the heat collector 1 to the preset value; through the circulation, the solar energy is stored in the heat storage and exchange pool 6 in the form of sensible heat; according to specific use requirements, the soil heat exchange pipeline 7 and the heat storage and exchange pool 4 are flexibly matched to realize the adjustment of the greenhouse under various conditions.

[0142] The working principle of the water pump control module is specifically as follows:

[0143] The water pump control module can automatically optimize in the solar energy storage process to realize full utilization of solar energy; the temperature value is fed back by the pool temperature collector 15, when the temperature value is less than the preset value T and the external light intensity is greater than the preset value S, the submersible pump 6 is controlled to be started by the water pump control module, the solar heat collector fluid outlet temperature, the ambient temperature and the wind speed data are collected and stored; if the outlet fluid temperature is greater than the inlet temperature, the water pump is continuously started and the determination result is output, recorded as 1; otherwise, the water pump is turned off and the determination result is output, recorded as 0; the stored data is transmitted to the water pump control module, the neural network is used for fitting, and the water pump start-stop logic rule model under different environmental temperature, wind speed and light intensity is obtained; after the preliminary fitting of the model is completed, the current state data is input to determine whether the water pump is started; at the same time, the parameters and the results are stored, and the logic model is fitted again to realize the automatic optimization of the heat storage and exchange pool in the solar energy storage process.

[0144] It should be noted that the temperature preset value T of the heat storage and exchange pool 4 is set according to the local light intensity and the environmental requirements of greenhouse crops, and the environmental setting range of greenhouse growth requirements; for example, for tomatoes, the recommended range of temperature preset value T is 60-80 DEG C, and the recommended range of preset value S is 400-600 W / m 2 .

[0145] The sunlight greenhouse heating system provided by the application realizes the storage of solar light energy in the heat storage and exchange pool during the period of abundant solar energy by arranging two solar heat storage and exchange subsystems and a soil-air heat exchange subsystem; the stability of greenhouse temperature and the self-regulating ability are greatly improved by flexible application of the soil-air heat exchanger and the heat storage and exchange pool to various weather conditions, so that the renewable geothermal energy and solar energy are used for heating the greenhouse; the electric heater is provided for heating the greenhouse in consideration of extreme weather; in the control aspect, the PID-MPC combined control strategy is designed, and the adjustment of the hot and humid environment of the greenhouse is realized through the secondary air mixing process; the control object of the PID controller is dynamically selected through the designed calculation model; the application realizes the purpose of adjusting the growth environment of greenhouse crops, and solves the problems of environmental pollution and energy consumption in the greenhouse heating, so that an energy-saving and feasible greenhouse heating scheme is provided for the users.

[0146] In the application, the solar collector, the heat storage and exchange pool and the tube bundle heat exchanger are connected to form a solar heat storage system of the sunlight greenhouse, and are combined with the soil-air heat exchange system using geothermal energy; the operation mode is changed according to the size of the heat load demand of the greenhouse, and the soil-air heat exchanger system is combined with the solar heat storage system or the solar heat storage system is used alone; the electric heater is started according to the demand in continuous rainy or extremely cold weather; when the PID controller and the MPC controller are used together, the dynamic control object of the PID-MPC combined control is selected through the designed calculation steps of operation rules, so as to meet the heat load of the sunlight greenhouse and the heat and humidity environment demand of the internal plants; the application can store the solar light energy through water in the daytime with sufficient sunlight, and release the heat in the water to the greenhouse at night, so that the whole process is energy-saving and environment-friendly, the operation energy consumption is low, and great convenience is provided for the users.

[0147] The above embodiment is only one of the implementation manners of the technical scheme of the application, and the scope of protection of the application is not limited to the embodiment, but also includes any changes, substitutions and other implementation manners easily thought by those skilled in the art within the technical scope disclosed by the application.

Claims

1. A solar greenhouse heating system, characterized in that: It includes two solar heat storage and heat exchange subsystems, a soil-air heat exchange subsystem, and an electric heater. The two solar heat exchange subsystems are located at both ends of the soil-air heat exchange subsystem, and are used to heat the air outside the greenhouse using solar energy and transport the heated air to the soil-air heat exchange subsystem. The soil-air heat exchange subsystem includes a soil heat exchange pipe, two air supply dry pipes, an air supply dry pipe, and an axial flow fan. The soil heat exchange pipe is buried underground in the solar greenhouse body, and two air supply dry pipes are respectively arranged at both ends of the soil heat exchange pipe; each air supply dry pipe is provided with a first air inlet, a second air inlet, a third air inlet and an air supply port; the first air inlet is connected to the air inside the solar greenhouse body, and the second air inlet is connected to the atmosphere outside the solar greenhouse body; the third air inlet on one of the air supply dry pipes is connected to the outlet of one of the solar heat storage and heat exchange subsystems, and the third air inlet on the other air supply dry pipe is connected to the outlet of the other solar heat storage and heat exchange subsystem, and the inlets of the two solar heat storage and heat exchange subsystems are both connected to the atmosphere outside the solar greenhouse body; The air supply main pipe is arranged above the ground inside the solar greenhouse body, and the two ends of the air supply main pipe are respectively connected to the air supply ports of the two air supply main pipes; the axial flow fan is arranged in the air supply main pipe and placed between the first air inlet and the third air inlet; the electric heater is arranged at the end of the air supply main pipe for electrically heating the air flow entering the air supply main pipe; Electric valves are installed at the inlet and outlet of the two solar thermal storage and heat exchange subsystems, and on the air supply and delivery main pipes; It also includes a control subsystem; the control subsystem includes a load calculation module; The load calculation module is used to calculate the total amount of indoor gas and the total amount of outdoor gas during the first air mixing in the solar greenhouse heating system based on the collected greenhouse temperature, relative humidity, operating temperature of the solar thermal storage and heat exchange subsystem, outlet temperature of the soil-air heat exchanger subsystem, ambient dry bulb temperature outside the solar greenhouse body, solar radiation intensity, and ambient wind speed; an opening adjustment module, configured to generate and send an opening adjustment instruction for the electric valve according to the total amount of indoor gas and the total amount of outdoor gas during the first air mixing; The load calculation module adopts PID-MPC joint control strategy; The heating mode selection process of the solar greenhouse heating system is as follows: Determine the nighttime demand load of the solar greenhouse , the night demand load of the solar greenhouse itself Compared with the design heating capacity under the preset soil-air heat exchange heating mode , Designed heating capacity under the preset single-side heat storage and heat exchange heating mode And the design heating capacity under the preset soil-air heat exchange heating and solar heat storage heat exchange combined heating mode Compare and obtain the heating mode selection result of the solar greenhouse heating system based on the heating supply comparison result.

2. A solar greenhouse heating system according to claim 1, characterized in that: The two solar thermal storage and heat exchange subsystems have the same structure and both use solar thermal storage and heat exchange devices; the solar thermal storage and heat exchange devices include solar collectors, thermal storage and heat exchange water tanks and tube bundle heat exchangers; The solar thermal collector is installed at the top of the rear wall of the solar greenhouse body, and the heat storage and heat exchange pool is installed at the end of the soil-air heat exchanger subsystem; the cold water inlet of the solar thermal collector is connected to the water outlet of the heat storage and heat exchange pool, and the hot water outlet of the solar thermal collector is connected to the water inlet of the heat storage and heat exchange pool; The tube bundle heat exchanger is arranged in a water storage and heat exchange pool. The air inlet of the tube bundle heat exchanger is connected to the atmosphere outside the solar greenhouse body, and the air outlet of the tube bundle heat exchanger is connected to the third air inlet; the tube bundle heat exchanger is used to use the hot water in the heat storage and heat exchange pool to heat the air in the tube bundle heat exchanger.

3. A solar greenhouse heating system according to claim 2, characterized in that: The solar thermal storage and heat exchange device also includes a water supply pipeline, a water return pipeline and a submersible pump; The inlet end of the water supply pipeline is connected to the outlet of the heat storage and heat exchange water tank, and the outlet end of the water supply pipeline is connected to the cold water inlet of the solar collector; the inlet end of the return water pipeline is connected to the hot water outlet of the solar collector, and the outlet end of the return water pipeline is connected to the water inlet of the heat storage and heat exchange water tank; the submersible pump is arranged at the outlet of the heat storage and heat exchange water tank and connected to the inlet end of the water supply pipeline.

4. A solar greenhouse heating system according to claim 2, characterized in that: The soil-air heat exchange subsystem also includes an air supply pipe inside the greenhouse, an air supply pipe outside the greenhouse, and several air supply branches; The inlet end of the greenhouse air supply pipe is connected to the air inside the solar greenhouse body, and the outlet end of the greenhouse air supply pipe is connected to the first air inlet; the inlet end of the greenhouse external air supply pipe extends to the outside of the solar greenhouse body and is connected to the atmosphere outside the solar greenhouse body; the outlet end of the greenhouse external air supply pipe is designed in two ways, one of which is connected to the second air inlet and the other is connected to the air inlet of the tube bundle heat exchanger; A plurality of air supply holes are opened on the air supply main pipe, and the plurality of air supply holes are evenly distributed along the axis of the air supply main pipe, and a plurality of air supply branch pipes are correspondingly arranged at the plurality of air supply holes.

5. A solar greenhouse heating system according to claim 1, characterized in that: The electric valves include a first electric valve, a second electric valve, a third electric valve, a fourth electric valve, a fifth electric valve, a sixth electric valve, a seventh electric valve and an eighth electric valve; The first electric valve is arranged at the inlet of the first solar thermal storage and heat exchange subsystem; the second electric valve is arranged on the first air supply main pipe and placed between the first air inlet and the second air inlet of the first air supply main pipe; the third electric valve is arranged at the outlet of the first solar thermal storage and heat exchange subsystem; the fourth electric valve is arranged on the supply air main pipe and is arranged close to one end of the first air supply main pipe; the fifth electric valve is arranged on the supply air main pipe and is arranged close to one end of the second air supply main pipe; the sixth electric valve is arranged on the second air supply main pipe and is placed between the first air inlet and the second air inlet of the second air supply main pipe; the seventh electric valve is arranged at the inlet of the second solar thermal storage and heat exchange subsystem; and the eighth electric valve is arranged at the outlet of the second solar thermal storage and heat exchange subsystem.

6. A solar greenhouse heating system according to claim 5, characterized in that: The control subsystem includes greenhouse information acquisition module and environmental data acquisition module; Greenhouse information collection module, used to collect the temperature in the greenhouse, the relative humidity in the greenhouse, the operating temperature of the solar thermal storage and heat exchange subsystem, and the outlet temperature of the soil-air heat exchanger subsystem; Environmental data acquisition module, used for the ambient dry-bulb temperature, solar radiation intensity and ambient wind speed outside the solar greenhouse body; The opening adjustment module is used to generate and send the opening adjustment instructions of the above-mentioned electric valves to the first electric valve, the second electric valve, the third electric valve, the fourth electric valve, the fifth electric valve, the sixth electric valve, the seventh electric valve and the eighth electric valve according to the total amount of indoor gas and the total amount of outdoor gas during the first air mixing.

7. A solar greenhouse heating system according to claim 6, characterized in that: The load calculation module adopts PID-MPC joint control strategy, which specifically includes PID controller and MPC controller; A PID controller is used to determine the indoor air mixing ratio during the first air mixing in the solar greenhouse heating system according to the collected temperature and relative humidity in the greenhouse; The MPC controller is used to obtain the total air volume required for heating in the solar greenhouse heating system based on the operating temperature of the solar thermal storage and heat exchange subsystem, the outlet temperature of the soil-air heat exchanger subsystem, the ambient dry-bulb temperature outside the solar greenhouse body, the solar radiation intensity and the ambient wind speed.

8. The operating method of a solar greenhouse heating system according to claims 1 to 7, characterized in that: The solar greenhouse heating system includes five working modes, namely: soil-air heat exchange heating mode, single-sided heat storage heat exchange heating mode, soil-air heat exchange heating and solar heat storage heat exchange combined heating mode, double-sided heat storage heat exchange heating mode and electric heating heating mode.

9. The operating method of a solar greenhouse heating system according to claim 8, characterized in that: The process of obtaining the heating mode selection result of the solar greenhouse heating system based on the heating supply comparison result is as follows: If the nighttime demand load of the solar greenhouse itself ,satisfy When , the soil-air heat exchange heating mode is selected; If the nighttime demand load of the solar greenhouse itself ,satisfy When , the single-side heat storage and heat exchange heating mode is selected; If the nighttime demand load of the solar greenhouse itself ,satisfy When the heat is high, the combined heating mode of soil-air heat exchange and solar heat storage and heat exchange is selected; If the nighttime demand load of the solar greenhouse itself ,satisfy When , the double-side heat storage and heat exchange heating mode is selected; If the nighttime demand load of the solar greenhouse itself ,satisfy When , select the electric heating mode.

10. The operating method of a solar greenhouse heating system according to claim 8, characterized in that: Nighttime demand load of the solar greenhouse itself , specifically: in, is the heat transfer coefficient of the solar greenhouse body, The coverage area of ​​the greenhouse insulation layer; The temperature of the greenhouse insulation layer; is the external ambient temperature; Designed heating capacity under the preset soil-air heat exchange heating mode , specifically: in, is the air density; The number of air heat exchanges; is the volume of air in the greenhouse; is the heat capacity of air; is the outlet temperature of the soil-air heat exchange subsystem; is the air temperature inside the greenhouse; Designed heating capacity under the preset single-side heat storage and heat exchange heating mode , specifically: in, is the outlet temperature of the solar thermal storage and heat exchange subsystem; Designed heating capacity under the preset soil-air heat exchange and solar heat storage heat exchange combined heating mode , specifically: in, The design heating capacity under the preset soil-air heat exchange heating mode; It is the designed heat supply under the preset single-side heat storage and heat exchange heating mode.

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