In addition to geographical location and climatic conditions, the distance between the wet curtain in the greenhouse and the flower greenhouse fan and the sensitivity of the flowers to temperature should also be considered. If the distance between the fan and the wet curtain is large (generally greater than 32 meters), it is recommended to use a 15cm thick wet curtain; if the cultivated flower is sensitive to greenhouse temperature and has high temperature resistance, it is recommended to use a 15cm thick wet curtain. Conversely, if the distance between the wet curtain and the fan in the greenhouse is small, or if the flower is less sensitive to temperature, a 10 cm thick wet curtain can be used. From an economic point of view, a 10 cm thick wet curtain is less than a 15 cm thick wet curtain, only 2/3 of its price. In addition, the larger the size of the air inlet of the wet curtain, the better. Since the size of the air inlet is too small, the static pressure is increased, thereby greatly reducing the efficiency of the fan and increasing the power consumption.
Flower greenhouse fan evaluation method:
1. The amount of ventilation required for the greenhouse = greenhouse length × width × 8 cfm (Note: cfm is the unit of air volume, that is, cubic feet per minute). The amount of ventilation per unit area should be adjusted according to altitude and light intensity.
2. Estimate the required wet curtain area. If you choose a 10cm thick wet curtain, the wet curtain area = the ventilation required for the greenhouse 250 / the wind speed if a 15cm thick wet curtain is used, the wet curtain area = the required ventilation / greenhouse wind speed 400 . The height of the wet curtain is obtained by dividing the area of the wet curtain by the length of the vent wall covered by the wet curtain. In wet areas, fan capacity and wet curtain size should be increased by 20%. According to the principle of hot air on the upper and cold wind, the fan curtain should be installed above the greenhouse, such as the greenhouse built in the early stage.
However, in recent years, the installation of flower greenhouse fans has shown a downward trend. In the greenhouse construction process, the height of the fan is generally installed at 1/3 of the seedbed, installed on the surface of the seedbed 2/3, and the wet curtain is installed 30cm above the ground, so the installation is mainly It is designed based on the actual temperature of the crop planted on the surface of the seedbed. Because the temperature of the top of the greenhouse is high, the leaves of the plant are not felt, so it doesn't matter. No need to spend unnecessary energy to reduce the temperature of the area that plants can't touch. At the same time, installing a fan under the seedbed is beneficial to plant root growth.
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