Selection principle
    Wet curtain size selection principle is to be wet curtain system to achieve the best results. Usually in greenhouse flower production is often used in a fibrous wet curtain thickness of 10 cm or 15 cm thick. Fibrous wet curtain 10 cm thick, running through the wet curtain air velocity of 76 m / min at best. 15 cm thick wet curtain paper requires an air speed of 122 m / min.
    The choice of the thickness of wet curtain, in addition to considering geographical location, climatic conditions, we must also look at the wet curtain and fan greenhouse distance and flower crops sensitive to temperature. If the distance between the fan and the greater wet curtain (usually more than 32 meters above), it is recommended to use 15 cm thick wet curtain; if the floriculture greenhouse temperature sensitive, high temperature tolerance of difference, it is recommended to use 15 cm thick wet curtain. Conversely, if the distance between the wet curtain and fan greenhouse or lesser extent from the flower of the low temperature-sensitive, you can use 10 cm thick wet curtain.
    From an economic point of view, 10 cm thick wet curtain price is lower than 15 cm thick wet curtain, only 2/3 of the price.
In addition, wet curtain air inlet size of the bigger the better. Because the size is too small inlet static pressure will increase, thus greatly reducing the efficiency of the fan, power consumption increases.
    Traditional estimates Greenhouse cooling device:
    1. Greenhouse Greenhouse required ventilation rate = length × width × 8cfm (Note: cfm air flow units, namely cubic feet per minute), the unit floor area of ??the ventilation rate should be adjusted according to the altitude and light intensity.
    2. estimates need to be wet curtain area. If you use 10 cm thick wet curtain, wet screens greenhouse area = necessary ventilation / wind speed 250. If the 15 cm thick wet curtain, wet screens greenhouse area = necessary ventilation / wind speed 400. Wet area with a curtain calculated by dividing the length of the wall wet curtain covering ventilation, obtained wet curtain height. In humid areas, wet curtain fan flow and to increase the size by 20%. In accordance with the hot air on the principle of cold air next, wet curtain fan should be installed at the top of the greenhouse, built early in the greenhouse as well.
    In recent years, however, high-end potted greenhouse fan wet curtain installed continued downward trend. Now in the greenhouse construction process, usually the height of the fans installed in the seedbed 1/3 or less, and 2/3 is mounted in the bed above the surface, more than 30 centimeters of wet curtain from the ground to start the installation, so installation is mainly based on planting in the bed crops on the actual feel of the design temperature. Because despite the high greenhouse temperature of the top, but do not feel the plant leaves, so it does not matter, there is no need to spend unnecessary energy consumption to reduce the plant out of the reach of zone temperature, while the fan is mounted under the bed, it is conducive to root growth .