Analysis of Structural Advantages of Multi story Thin Film Greenhouses

The main body of the connected thin film greenhouse adopts a truss type hot-dip galvanized steel frame combination structure. Greenhouses can be divided into double arch spans and single arch spans. There are many arched drainage ditches with a large span and a grid structure.

The advantages of a multi span membrane greenhouse structure are that it reduces the top space, increases the building area, and the spacious indoor space facilitates users to achieve mechanized production and operation; At the same time, it has an impact on the winter insulation and overall wind resistance performance of the greenhouse. In winter and at night, when used in conjunction with insulation nets, it can reduce heat loss and heating space, thereby saving greenhouse operating costs. This type of greenhouse is suitable for planting flowers, vegetables, and seedlings in most parts of China.

By utilizing the high reflection and low transmission radiation characteristics of aluminum foil, the heat loss caused by longwave radiation and convection can be reduced. Has good insulation effect. In addition, it also has breathability and moisture permeability, preventing excessive indoor humidity. It can also be used for shading and cooling in summer. Shading can reduce transmittance by 4%, but it can save 40% of energy. At present, aluminum foil reflective insulation curtain is a commonly used form of insulation curtain for large greenhouses in various countries. Aluminum foil reflective insulation curtain adopts strip shaped aluminum foil, aluminum plating or mixed aluminum. In a multi story film greenhouse, in addition to regulating humidity, it is also important to regulate air humidity and gas composition. Due to its excellent moisturizing properties, the indoor air humidity often remains saturated under closed conditions, and attention should be paid in the harsh winter season. Such high humidity is a good environment for the occurrence and prevalence of various diseases, so ventilation is needed to reduce indoor air humidity. Even in severe winter, we must maintain ventilation and not freeze the seedlings to death. When the disease is severe in spring and autumn, the main way to solve the problem of moisture is through drainage, and indoor air humidity should be controlled below 85%. Ventilation also has the function of regulating gases. Under closed conditions, indoor carbon dioxide is severely insufficient. Therefore, the normal indoor carbon dioxide concentration should be maintained at 0.03% to meet the needs of vegetables through ventilation. The application of carbon dioxide fertilizer in a continuous thin film greenhouse has a good effect. In general, half an hour after the grass curtain is lifted, it will inhale carbon dioxide, and ventilation will only end after half an hour. The application concentration is 0.15%. After fertilization, ammonia will accumulate in the plastic greenhouse, and harmful gases should be discharged through ventilation.