It is well known that greenhouses are used to increase the temperature so that vegetables can grow normally in winter. However, with the promotion and use of standardized greenhouses in recent years, we have found that some greenhouses can still carry out normal summer seedling cultivation, vegetable and flower growth work even in the hot summer. In some greenhouses, the temperature in the greenhouse is as high as 40 to 50 degrees at noon in summer, and no plants can grow. The factors that affect the internal temperature of the greenhouse are mainly light and ventilation.
1. External electric shading system of greenhouses
At present, the external shading nets of multi-span greenhouses are mostly round wire black nets with a shading rate of 75%. This kind of shading net is slightly more expensive, but the effective service life is up to five years. In summer, the top of the greenhouse is driven by a motor to drive the transmission system to unfold the shading net, which can block most of the sunlight outside the greenhouse and effectively reduce the indoor greenhouse by 3 to 5 degrees Celsius.
2. Natural ventilation system of greenhouse
The natural ventilation system is to install vents around or on the top of the greenhouse. Due to the principle of hot air floating, the hot air in the greenhouse will be dissipated to the outside through the vents on the top, which can also have a certain cooling effect. However, under the best natural ventilation conditions, it can only achieve the effect of outdoor temperature.
3. Fan water curtain forced exhaust cooling system
The principle of fan water curtain forced cooling is to arrange the fan and water curtain on the opposite side of the greenhouse. The fan exhausts the high-temperature air in the room by exhausting air to the outside of the greenhouse, and then the outdoor air absorbs heat and cools down after the evaporation of the water curtain. The cool air enters the greenhouse to achieve the cooling effect. What do you pay most attention to? The number and power of the fans, the layout area of the water curtain, and the air humidity will affect its cooling effect. Through reasonable layout, the temperature inside the greenhouse can reach 28 degrees Celsius in the hot summer.
4. High-pressure spray system
The water particles released into the air by the spray cooling system absorb a large amount of heat from the surrounding environment during the vaporization process, thereby reducing the temperature of the surrounding environment. It is an effective means of preventing heatstroke and cooling down. By installing the high-pressure spray system on the top of the greenhouse, it can effectively reduce the temperature. (This cooling method is widely used in greenhouse production in the Netherlands)
