AU2021100016A4

AU2021100016A4 - Greenhouse cooling system and method

Info

Publication number: AU2021100016A4
Application number: AU2021100016A
Authority: AU
Inventors: Jianhu Han; Lijuan Qie; Qingzhen Yin
Original assignee: Economic Crop Res Institute Of Hebei Academy Of Agriculturel And Forestry Sciences
Current assignee: Economic Crop Research Institute Of Hebei Academy Of Agriculturel And Forestry Sciences
Priority date: 2021-01-04
Filing date: 2021-01-04
Publication date: 2021-03-18
Anticipated expiration: 2029-01-04

Abstract

The present invention discloses a greenhouse cooling system and method. The greenhouse cooling system comprises a greenhouse, a rainwater collection system, a water storage pool, a micro-spray system and an air supply system. When the greenhouse cooling system is used for cooling the greenhouse, the greenhouse is closed first; a blower fan and an exhaust fan are turned on; meanwhile, the micro-spray system is turned on, so that the greenhouse is cooled by the wet and cold air in the water storage pool; and when the temperature in the greenhouse is lower than a temperature appropriate for the growth of crops, the blower fan, the exhaust fan and the micro-spray system are turned off to stop cooling. The present invention has good cooling effect, low energy consumption, water conservation and environmental protection. Drawings of Description - -- - - - - - -, - -~ - - - Fig.1I I

Description

Drawings of Description

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Fig.1I

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Description

GREENHOUSE COOLING SYSTEM AND METHOD

Technical Field

The present invention belongs to the technical field of agricultural greenhouses, and particularly relates to a greenhouse cooling system and method.

Background

Greenhouse is equipment special for the growth and cultivation of crops. The greenhouse can keep good heat preservation and moisturization effects in low-temperature seasons, so that crops can produce stably in low-temperature seasons. However, the temperature in greenhouse is too high and the growth of the crops is adversely affected in high-temperature seasons. For example, if temperatures optimum for the growth of solanaceous fruit vegetables at a seedling stage are 25-28°C in the daytime and 15-18°C at night, when the night temperature exceeds 22°C at a blossoming and fruiting stage, flowers and fruits will drop. At present, wet curtain-fan cooling is a most commonly used method for cooling the greenhouse. In the method, a desired cooling effect cannot be achieved when the thickness of the wet curtain is too small; and the wind resistance will be increased and energy consumption is high when the thickness is too large.

Summary

In view of the above technical status, the purposes of the present invention are to provide a greenhouse cooling system with energy conservation, water conservation and good cooling effect, and to provide a method for cooling by utilizing the system. The following technical solution is adopted in the present invention: A greenhouse cooling system comprises a greenhouse, a rainwater collection system, a water storage pool, a micro-spray system and an air supply system; the

Description

rainwater collection system comprises apron slopes located at both sides of the greenhouse and a sedimentation pool connected with the apron slopes through a confluence pipeline; a filter screen is arranged at a water outlet of the sedimentation pool; the sedimentation pool is connected with a water inlet of the water storage pool through a pipeline; the water storage pool is arranged below the ground; the top of the water storage pool is covered with a cover plate; the cover plate is covered with a soil layer; the micro-spray system comprises a trunk pipe and branch pipes arranged at the top of the water storage pool in a manner of communicating with the trunk pipe; the bottom of the trunk pipe is located below a water surface in the water storage pool; the branch pipes are uniformly distributed at the top of the water storage pool; micro-nozzles are arranged on the branch pipes; the air supply system comprises an air supply inlet and an air outlet, which are respectively reserved in a left side and a right side of the water storage pool; the air supply inlet is connected with a blower fan; the air outlet is connected with an exhaust fan; an outlet of the exhaust fan is connected with an air distribution pipe; and the air distribution pipe is arranged at the top of the greenhouse and is provided with air distribution holes. Preferably, the greenhouse is located in a south-north direction and comprises a framework and a greenhouse film, wherein arch bars of the framework are fixedly connected with longitudinal pull bars in a cross manner; air outlets are arranged at both sides of the greenhouse; and gables at both ends are respectively provided with a door. Preferably, the sedimentation pool is at least 1 m away from a water inlet of the water storage pool, and has a volume of 1-2 m3 .

Preferably, the water storage pool is arranged under the ground in the greenhouse; and the interior of the water storage pool is poured with impermeable concrete and is brushed with waterproof glue to prevent water leakage. Preferably, the thickness of the soil layer covered on the water storage pool is at least 0.6 m; the water surface in the water storage pool is at least 3 m away from

Description

the top of the water storage pool; the water storage pool is further provided with an overflow hole connected with the apron slopes; the apron slopes are communicated with a natural ditch to discharge water overflowing from the water storage pool; and the water storage pool is further connected with a drip irrigation or spray irrigation device for watering crops in the greenhouse. Preferably, the water storage pool has a direction the same as that of the greenhouse and has an area of 30%-40% of the area of the greenhouse. Preferably, the air distribution pipe is arranged at the top inside the greenhouse along the direction of the greenhouse; and air distribution holes are uniformly formed in both sides of the air distribution pipe. The present invention also provides a method for cooling the greenhouse by using the system, comprising the following steps: closing the greenhouse and turning on the blower fan and the exhaust fan when the temperature in the greenhouse exceeds a temperature appropriate for the growth of crops; meanwhile, turning on the micro-spray system so that the greenhouse is cooled by the wet and cold air in the water storage pool; and turning off the blower fan, the draught fan and the micro-spray system to stop cooling when the temperature in the greenhouse is lower than the temperature appropriate for the growth of crops. The present invention has the beneficial effects that: (1) The cold air in the water storage pool built at a certain depth under the ground is used for cooling the greenhouse in the present invention, so that the temperature in the greenhouse can be lowered effectively; and the micro-spray system arranged in the water storage pool can further lower the temperature of the air in the water storage pool, ensure the cooling effect and appropriately increase the air humidity, thereby benefiting the growth of the crops and avoiding the damage of the cold air to the crops.

Description

(2) The water storage pool is built under the greenhouse and is covered with the soil layer; and the soil layer can be used for normal crop cultivation without occupying other farmlands, thereby improving the land utilization rate. (3) The water storage pool is communicated with the rainwater collection system; the rainwater collection system collects rainwater into the water storage pool through the apron slopes, a water pipeline, the sedimentation pool and the filter screen, and cools the air in the pool through the micro-spray system; and when watering is required in the greenhouse, the rainwater collected in the water storage pool can be used for irrigating the crops in the greenhouse through the drip irrigation or spray irrigation device, thereby saving the water consumption of irrigation and improving the utilization rate of water resources.

Description of Drawings

Fig. 1 is a structural schematic diagram of the present invention; and Fig. 2 is a schematic diagram of layout of a rainwater collection system in the present invention. In the figures, 1 greenhouse, 2 water storage pool, 2-1 water inlet, 2-2 overflow hole, 3 apron slope, 4 confluence pipeline, 5 sedimentation pool, 6 water pump, 7 trunk pipe, 8 branch pipe, 9 micro-nozzle, 10 air supply inlet, 11 air outlet, 12 blower fan, 13 exhaust fan, 14 air distribution pipe, 15 air distribution hole and 16 drip irrigation or spray irrigation device.

Detailed Description

Specific embodiments of the present invention will be further described in detail in combination with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but not to limit a scope of the present invention.

Description

As shown in Fig. 1 and Fig. 2, a greenhouse cooling system according to the present embodiment comprises a greenhouse 1, a rainwater collection system, a water storage pool 2, a micro-spray system and an air supply system. The rainwater collection system comprises apron slopes 3 located at both sides of the greenhouse 1 and a sedimentation pool 5 connected with the apron slopes 3 through a confluence pipeline 4; a filter screen is arranged at a water outlet of the sedimentation pool 5; the sedimentation pool 5 is connected with a water inlet 2-1 of the water storage pool 2 through a pipeline; the water storage pool 2 is arranged under the ground inside the greenhouse 1; the water storage pool 2 is covered with a soil layer; the micro-spray system comprises a trunk pipe 7 with a water pump 6, and branch pipes 8 arranged at the top of the water storage pool 2 in a manner of communicating with the trunk pipe 7; the bottom of the trunk pipe 7 is located below a water surface in the water storage pool 2; the branch pipes 8 are uniformly distributed at the top of the water storage pool 2; the air supply system comprises an air supply inlet 10 and an air outlet 11 which are respectively reserved in a left side and a right side of the water storage pool 2; the air supply inlet 10 is connected with a blower fan 12; the air outlet 11 is connected with an exhaust fan 13; an outlet of the exhaust fan 13 is connected with an air distribution pipe 14; and the air distribution pipe 14 is arranged at the top of the greenhouse 1 and is provided with air distribution holes 15 at both sides of the pipe body. The greenhouse 1 is located in a south-north direction, has a length of 60 m from south to north, a span of 12 m from east to west, a height of 3.5 m, a shoulder height of 1.8 m and a burial depth of 0.5 m, and is composed of a framework and a greenhouse film. Arch bars of the framework are made of D32*1.8 hot-dip galvanized steel pipes; seven longitudinal pull bars are made of D25*1.4 hot-dip galvanized steel pipes; and four longitudinal clamping grooves are provided. The arch distance is 1 m; and the longitudinal pull bars are connected with the arch bars in a cross manner and are fixed by spring clips and herringbone clips. The film is

Description

rolled up at both sides for ventilation. The greenhouse film is a long-lived greenhouse film. The anti-corrosion life of all pipe fittings and connectors is 10-15 years. Gables at a north end and a south end are respectively provided with a set of doors of 1.8 mx1.8 m. The apron slopes 3 are located at an east side and a west side of the greenhouse 1. The greenhouse film and the apron slopes 3 intercept rainfall runoff and then introduce the rainfall runoff into the confluence pipelines 4. The confluence pipelines 4 are communicated with each other by a PE plastic pipe with a diameter of p100. Then, the rainfall runoff flows into the sedimentation pool 5 and the filter screen for sedimentation and filtration and then flows into the water storage pool 2. A plurality of sedimentation pools 5 can be provided according to the specifications of the greenhouse. Eight sedimentation pools are provided in the present embodiment, wherein one is arranged at the confluence pipeline every 15 m along the directions of the apron slopes at both sides; each sedimentation pool 5 is 1I m3 ; and the last two are arranged about 1 m away from the water inlet of the water storage pool 2. The apron slopes 3 and all sedimentation pools 5 are built by bricks and stones and plastered with cement. The rainwater collection system collects the rainwater, to save the water consumption of irrigation and improve the utilization rate of water resources. The water storage pool 2 is built under the greenhouse 1, is also located in the south-north direction, and has a length of 32 m, a width of 8 m and a height of 5 m; the bottom of the water storage pool is 5.6 m away from the ground; and the water storage pool 2 is built first and then is backfilled with a 0.6 m soil layer. The water storage pool 2 stores 2 m deep water, with a 3 m high space at an upper part. The water storage pool 2 is sealed and poured with reinforced concrete. To facilitate the load bearing of the top of the pool, load-bearing walls are arranged in the pool to divide the pool into eight rooms in a single row. The load-bearing walls are provided with doors for circulating water and wet air. In order to further enhance

Description

the air circulation effect between the rooms, air vents can be formed between the top of the load-bearing walls and the top of the pool to facilitate the circulation of wet and cold air. The bottom of the pool is tamped with C15 concrete; a plastic film is laid outside the bottom and the walls of the pool; and the walls, the bottom and the top of the pool are poured with C30 impermeable reinforced concrete. The thickness of the walls is 40 cm; and the waterproof glue is brushed in the pool to prevent water leakage. The reinforcement models are pl4@150 and p 1 2@150; the wall pouring thickness is 30 cm; the pool has a bottom thickness of 40 cm and a top thickness of 10 cm; and the air vents are formed by DN200 steel pipes and elbows. An inner wall of the water storage pool 2 is plastered with five layers of cement mortar (brushed with 1: 2.5+5% waterproof powder + polyurethane waterproof coating). The water storage pool 2 is built under the greenhouse 1, to facilitate the collection of the rainwater from the greenhouse, the cooling of the greenhouse and the irrigation of vegetables in the greenhouse without occupying other farmlands, thereby increasing the land utilization rate. Openings of the water storage pool 2 are closed with prefabricated concrete cover plates, on which access openings are reserved; the blower fan 12 is mounted at an upper right opening; the exhaust fan 13 is mounted at an upper left opening; the outlet of the exhaust fan 13 is connected with the air distribution pipe 14; the air distribution pipe 14 is arranged at the top of the greenhouse 1 in the south-north direction and is provided with the air distribution holes 15 at both sides of the pipe body. An overflow hole 2-2 not smaller than a water inlet 2-1 is reserved at one side of the water storage pool 2. In the present embodiment, the water outlet is 4.5 m away from the bottom of the pool; rainwater in the pool can flow out from the overflow hole after reaching the height of the overflow hole; and the overflow hole 2-2 is connected with the natural ditch to introduce excessive rainwater into the natural ditch. A small water pump is mounted in the water storage pool 2; and

Description

when the cooling system of the present invention needs to be used and the water level in the water storage pool is higher than 2 m, the water pump is turned on to pump out the rainwater so that the water level becomes 2 m high, and the pumped rainwater can be used for irrigation or discharged into the natural ditch. The micro-spray system is arranged in the water storage pool 2, and comprises the trunk pipe 7 with the water pump 6 and the branch pipes 8 communicated with the trunk pipe 7. The bottom of the trunk pipe 7 is located below the water surface in the water storage pool 2; and the branch pipes 8 are arranged at a position 0.5 m away from the top of the water storage pool 2. In the present embodiment, the trunk pipe 7 is a <p50 PE pipe; the branch pipes 8 are three <p25 PE pipes arranged side by side in the south-north direction of the water storage pool 2; and micro-nozzles 9 are uniformly arranged on the branch pipes 8. The micro-spray system in the water storage pool 2 further lowers the air temperature in the water storage pool 2 and increases the air humidity. The wet and cold air has a good cooling effect and avoids the damage of the cold air to plants. The rainwater flows into the water storage pool 2 for storage, and can be used for drip irrigation or spray irrigation under a mechanical power of the small water pump when vegetable crops in the greenhouse need to be watered. The blower fan 12 has a ventilation rate of 18000 m3 /h and 30-40 times/h, and is horizontally kept on a mounting bracket. The ventilation rate of the exhaust fan 13 is 85%-95% of an air supply rate of the blower fan 12. In the present embodiment, the air distribution pipe 14 has a length of 55 m, and is located to avoid turns and branch pipes as much as possible. The wet and cold air in the water storage pool 2 is delivered into the greenhouse 1 through the exhaust fan 13, the air distribution pipe 14 and the air distribution holes 15, i.e., a method that the wet and cold air in the water storage pool 2 is used for delivering the wet and cold air to the greenhouse in summer, thereby lowering the day temperature and the night temperature of the greenhouse 1 in summer, so that the

Description

greenhouse 1 keeps the temperature appropriate for the growth of the solanaceous fruit vegetables, increases the yield of the solanaceous fruit vegetables and increases the output value. Taking the solanaceous fruit vegetables as an example, a method for using the greenhouse cooling system of the present invention comprises the following steps: Temperatures optimum for the growth of the solanaceous fruit vegetables at a seedling stage is controlled at 25-28°C in the daytime and 15-18°C at night. The temperature appropriate for the growth at a vegetative growth stage is 20-25°C; the temperature at a blossoming and fruiting stage should not exceed 30°C; it is more conducive to the growth that the night temperature is 5-10°C lower than the day temperature; and when the night temperature is higher than 22°C or lower than 0C, flowers and fruits will drop. During rainfall, the greenhouse film and the apron slopes 3 of the greenhouse 1 intercept rainfall runoff and then introduce the rainfall runoff into the confluence pipeline 4; and the rainwater is purified through the sedimentation of the sedimentation pool 5 and the filtration of the filter screen and then is delivered into the water storage pool 2 for storage. In hot summer seasons and periods, opening the vents at the left side and the right side of the greenhouse 1 is not enough to lower the temperature of the greenhouse 1 to the temperature appropriate for the growth of the solanaceous fruit vegetables. At this moment, the vents of the greenhouse 1 can be closed; the blower fan 12 and the exhaust fan 13 can be turned on; and meanwhile, the micro-spray system is turned on, so that the wet and cold air in the water storage pool 1 is pumped out and distributed to various places in the greenhouse through the air distribution holes 15 to cool the greenhouse. When the temperature in the greenhouse is lower than the temperature appropriate for the growth of the solanaceous fruit vegetables, the system is turned off to stop cooling. When the temperature is too high at night, the system can also be turned on, and the vents of the greenhouse 1 can be closed to reduce the night temperature for the

Description

greenhouse. The appropriate day temperature and night temperature in the greenhouse can be ensured to meet growth needs of the solanaceous fruit vegetables. When the crops in the greenhouse need to be watered, the rainwater stored in the water storage pool 2 can be pumped out by the water pump to irrigate the crops in the greenhouse by a drip irrigation or spray irrigation device 16. When ventilation is required in the greenhouse, the vents at both sides of the greenhouse are opened to allow air circulation between the greenhouse and the outside. The structure of the greenhouse can be formed by double frameworks and double greenhouse films, to enhance the airtightness of the greenhouse and improve the cooling effect of the greenhouse during circulation of the wet and cold air, so that the cooling effect of the greenhouse is more sufficient, the appropriate day temperature and night temperature can be ensured more favorably, and the yield of the solanaceous fruit vegetables in the greenhouse can be increased. To lower the temperature of the greenhouse in summer, the structure of the greenhouse can be changed to various types of greenhouses, such as multi-span plastic greenhouses, double-arch plastic greenhouses and modified plastic greenhouses. The water storage pool 2 can also be built below the outdoor ground adjacent to the greenhouse; and the rainwater from other greenhouses can be collected by the rainwater collection system to ensure a sufficient water source. When the cooling system provided by the present invention is compared with the wet curtain-fan cooling system in greenhouses of the same size, the temperature in the greenhouses is uniformly set at 35°C; and the cooling system provided by the present invention and the wet curtain-fan cooling system are turned on at the same time, and respectively take 1 h and 0.5 h to lower the temperature in the greenhouses to 28°C. Compared with the wet curtain-fan

Description

cooling system, the cooling system provided by the present invention reduces the energy consumption by 60% and reduces the equipment cost by 55%.

Claims

1. A greenhouse cooling system, comprising a greenhouse (1), a rainwater collection system, a water storage pool (2), a micro-spray system and an air supply system, wherein the rainwater collection system comprises apron slopes (3) located at both sides of the greenhouse (1) and a sedimentation pool (5) connected with the apron slopes (3) through a confluence pipeline (4); a filter screen is arranged at a water outlet of the sedimentation pool (5); the sedimentation pool (5) is connected with a water inlet (2-1) of the water storage pool (2) through a pipeline; the water storage pool (2) is arranged below the ground; the top of the water storage pool is covered with a cover plate; the cover plate is covered with a soil layer; the micro-spray system comprises a trunk pipe (7) and branch pipes (8) arranged at the top of the water storage pool (2) in a manner of communicating with the trunk pipe (7); the bottom of the trunk pipe (7) is located below a water surface in the water storage pool (2); the branch pipes (8) are uniformly distributed at the top of the water storage pool (2); micro-nozzles (9) are arranged on the branch pipes (8); the air supply system comprises an air supply inlet (10) and an air outlet (11) which are respectively reserved in a left side and a right side of the water storage pool (2); the air supply inlet (10) is connected with a blower fan (12); the air outlet (11) is connected with an exhaust fan (13); an outlet of the exhaust fan (13) is connected with an air distribution pipe (14); and the air distribution pipe (14) is arranged at the top of the greenhouse (1) and is provided with air distribution holes (15).

2. The greenhouse cooling system according to claim 1, wherein the greenhouse (1) is located in a south-north direction and comprises a framework and a greenhouse film; arch bars of the framework are fixedly connected with longitudinal pull bars in a cross manner; air outlets are arranged at both sides of the greenhouse; and gables at both ends are respectively provided with a door.

3. The greenhouse cooling system according to claim 1, wherein the sedimentation pool (5) is at least 1 m away from a water inlet (2-1) of the water storage pool (2), and has a volume of 1-2 m3 .

Claims

4. The greenhouse cooling system according to claim 1, wherein the water storage pool (2) is arranged under the ground in the greenhouse (1); and the interior of the water storage pool is poured with impermeable concrete and is brushed with waterproof glue to prevent water leakage.

5. The greenhouse cooling system according to claim 1, wherein the thickness of the soil layer covered on the water storage pool (2) is at least 0.6 m; the water surface in the water storage pool (2) is at least 3 m away from the top of the water storage pool (2); the water storage pool (2) is further provided with an overflow hole (2-2) connected with the apron slopes (3); the apron slopes (3) are communicated with a natural ditch to discharge water overflowing from the water storage pool; and the water storage pool (2) is further connected with a drip irrigation or spray irrigation device (16) for watering crops in the greenhouse.

6. The greenhouse cooling system according to claim 1, wherein the water storage pool (2) has a direction the same as that of the greenhouse (1) and has an area of 30%-40% of the area of the greenhouse.

7. The greenhouse cooling system according to claim 1, wherein the air distribution pipe (14) is arranged at the top inside the greenhouse along the direction of the greenhouse; and air distribution holes (15) are uniformly formed in both sides of the air distribution pipe (14).

8. A method for cooling the greenhouse by using the system of any one of claims 1-7, comprising the following steps: closing the greenhouse (1) and turning on the blower fan (12) and the exhaust fan (13) when the temperature in the greenhouse (1) exceeds a temperature appropriate for the growth of crops; meanwhile, turning on the micro-spray system so that the greenhouse (1) is cooled by the wet and cold air in the water storage pool (2); and turning off the blower fan (12), the draught fan (13) and the micro-spray system to stop cooling when the temperature in the greenhouse is lower than the temperature appropriate for the growth of crops.