3. Durability of greenhouse
The durability of greenhouse construction must be considered. The durability of greenhouse is affected by the aging resistance of greenhouse materials and the bearing capacity of the main structure of greenhouse. In addition to its own strength, the durability of transparent materials is also reflected in the fact that the light transmittance of materials decreases with time, and the degree of light transmittance attenuation is the decisive factor affecting the service life of transparent materials. The service life of general steel structure greenhouse is more than 15 years. The design wind and snow load is required to use the maximum load once in 25 years; the service life of simple bamboo and wood structure greenhouse is 5-10 years, and the design wind and snow load is required to use the maximum load once in 15 years.
4. Temperature demand of greenhouse
Different plants have different requirements for temperature, and the temperature of different greenhouse is also different. But generally speaking, the temperature of greenhouse is 3 ~ 10 ℃ higher than that of outdoor, and the maximum temperature is about 30 ℃. For the plants with high temperature demand, the greenhouse in the north of China should take certain warming measures in winter.
Heating mode of greenhouse
The conventional heating mode of greenhouse is electric air conditioning and hot blast stove system. However, these two kinds of equipment have the disadvantages of high investment, high energy consumption, poor effect, and are only suitable for the production of high-grade and high added value greenhouses.
Ground source heat pump technology is now in a rapid rise process, as the ground source heat pump technology itself, whether in foreign or domestic has been very mature. Has been widely used in residential, office, shopping malls, factories, stadiums and many large-scale buildings. As a completely pollution-free green air-conditioning form, its biggest advantage is to save the operation cost of air-conditioning system and land space, and we need to pay only a little more investment.