How to choose a flower greenhouse cooling system

First of all, first to understand the principle of the role of the fan. When the outdoor hot air is sucked through the water-absorbing wet curtain, the moisture on the wet paper is absorbed by the moisture, thereby reducing the temperature of the air entering the greenhouse. Typically, the "wet wall" consisting of wet curtains, water distribution systems, water pumps and water tanks is built continuously along the walls of the greenhouse, while the fans are concentrated on the other side of the greenhouse. evaporative cooling pad must be kept moist to ensure the completion of the evaporation process, according to the size of the greenhouse and the area, choose the appropriate fan installed in the wet curtain on the wall, so that the air through the greenhouse smoothly.
The effect of evaporative cooling is related to the degree of drying of the air, that is, the difference between the temperature of the wet bulb and the temperature of the dry bulb. The temperature difference between the wet and dry bulbs of the air is not only changed with the geographical position and the seasons, but also changes in the course of the day. Although the change in dry bulb temperature may be as high as 14 ¡ã C a day, the rate of change in wet bulb temperature is only about 1/3 of the dry bulb humidity. Therefore, in the high humidity area at noon, the evaporation system is still able to cool, which is required for greenhouse production.
Selection principle

The choice of wet curtain size is to make the wet curtain system achieve the best results. Usually in the flower production greenhouse is often used in 10 cm thick or 15 cm thick fiber evaporative cooling pad. 10 cm thick fibrous wet curtain, greenhouse cooling pads in the wet curtain through the air speed of 76 m / min when the best results. 15 cm thick paper wet curtain requires an air speed of 122 m / min.
The choice of what kind of thickness of the wet curtain, in addition to considering the location of the geographical location, climate conditions, but also should see the greenhouse wet curtain and the distance between the fan and the temperature of the flower crop sensitivity. If the distance between the fan and the wet curtain is larger (usually more than 32 meters), it is recommended to use a 15 cm thick wet curtain; if the cultivated flowers are more sensitive to the greenhouse temperature, the tolerance to high temperature is poor, it is recommended to use 15 cm thick Wet curtain. On the other hand, if the distance between the wet curtain and the fan in the greenhouse is small or the flower is less sensitive to temperature, a 10 cm thick wet curtain can be used.
From an economic point of view, 10 cm thick wet curtain price is less than 15 cm thick evaporative cooling pad, only its price of 2/3.
In addition, the wet curtain of the larger the better the size of the air inlet. Because the size of the inlet is too small will increase the static pressure, which greatly reduces the efficiency of the fan, increase power consumption.
Estimation of greenhouse cooling equipment:
1. Greenhouse required ventilation = greenhouse length ¡Á width ¡Á 8cfm (Note: cfm for the air flow unit, that is, cubic feet per minute), the unit floor area ventilation should be based on altitude and light intensity to adjust.

2. Estimate the required wet curtain area. If you choose 10 cm thick wet curtain, celdek evaporative cooler pads area = greenhouse required ventilation / wind speed 250. If you use 15 cm thick wet curtain, wet curtain area = greenhouse required ventilation / wind speed 400. Calculate the wet curtain height by dividing the calculated wet curtain area by the length of the ventilation wall covered by the wet curtain. In wet climates, fan airflow and wet curtain size should be increased by 20%. In accordance with the principle of hot air on the cold air in the next, the fan wet curtain should be installed in the greenhouse above the early construction of the greenhouse as well.
However, in recent years, high-grade potted greenhouse greenhouse wet curtain installation has continued downward trend. Now in the greenhouse construction process, the general will be the fan height of 1/3 installed in the seedbed below, 2/3 installed in the seed bed above the wet curtain from the ground above 30 cm began to install, so the installation is mainly based on planting On the crop actually felt the temperature to design. Because the top of the greenhouse is very high, but the plant foliage can not feel, so it does not matter, there is no need to reduce the plant contact with the regional temperature, while the fan installed in the seedbed below, is conducive to plant root growth.