USB Cable,HDMI Cable,Speaker Cable,Network Cable,Type-C Cable ,Audio&Video Cable Changzhou Satidi Import and Export Co., Ltd. , https://www.guanjiejt.com
How to choose a floral greenhouse fan wet curtain system
The fan wet curtain cooling system is currently the most widely used, effective, and most suitable method for the growth of crops in the greenhouse of flower production. How to properly install the fan curtain system in the construction of the flower greenhouse and give full play to its function as a flower Growth plays a catalytic role? The principle of action First of all, first understand the principle of the fan. When outdoor hot air is drawn through the wet curtain filled with water, moisture on the wet curtain absorbs heat to evaporate, thereby reducing the temperature of the air entering the greenhouse. Usually, a “wet wall†consisting of a wet curtain, a wet curtain water distribution system, a water pump and a water tank is continuously built along one side of the greenhouse, while fans are concentrated on the other side of the greenhouse. The wet curtain must be kept moist to ensure the completion of the evaporative cooling process. According to the size of the greenhouse and the area in which it is located, a suitable fan can be installed on the wall opposite the wet curtain to allow the air flow to pass through the greenhouse smoothly. The effect of evaporative cooling is related to the degree of drying of the air, ie, the difference between the wet bulb temperature of the air and the dry bulb temperature. The temperature difference between dry and wet bulbs in the air varies not only with geographical location and season but also during the day. Although the change in dry-bulb temperature during the day may be as high as 14°C, the wet-bulb temperature changes by approximately 1/3 of the dry-sphere humidity. Therefore, at noon in the high-humidity area, the evaporation system can still cool down, which is also required for greenhouse production. Selection Principle The principle of wet curtain size selection is that the wet curtain system should achieve the best results. Usually used in the flower production greenhouse is a 10 cm thick or 15 cm thick cellulosic wet curtain. A 10 cm thick cellulosic wet curtain performs best when the air speed through the wet curtain is 76 meters per minute. A 15 cm thick paper wet curtain requires an air speed of 122 m/min. The choice of the thickness of the wet curtain, in addition to considering the location of the location, weather conditions, we should also look at the distance between the wet curtain and the fan in the greenhouse and the sensitivity of the flower crops to the temperature. If the distance between the fan and the wet curtain is greater (usually more than 32 meters), it is recommended to use a 15 cm thick wet curtain; if the cultivated flowers are sensitive to greenhouse temperature, poor tolerance to high temperature, it is recommended to use 15 cm thick Wet curtains. Conversely, 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 economical point of view, a 10 cm thick wet curtain is less than 15 cm thick and only 2/3 of its price. In addition, the larger the inlet size of the wet curtain, the better. Because the size of the air inlet is too small, the static pressure will increase, which will greatly reduce the efficiency of the fan and increase the power consumption. The method for estimating the cooling equipment of traditional multi-span greenhouses: 1. The necessary ventilation of the greenhouse = the width of the greenhouse length of 8 cfm (Note: cfm is the air flow unit, ie cubic feet per minute). The ventilation of the unit ground area should be based on the altitude and light intensity, etc. Make adjustments. 2. Estimate the required wet screen area. If a 10 cm wet curtain is selected, the area of ​​the wet screen = the required ventilation/wind speed of 250 in the greenhouse. If a wet curtain of 15 cm is used, the area of ​​the wet curtain = the required ventilation of the greenhouse / wind speed 400. The wet curtain height is obtained by dividing the calculated wet curtain area by the length of the ventilated curtain wall. In humid climate areas, the fan air volume and wet screen size increase by 20%. According to the principles of hot air and cold air, the wet curtain of the fan should be installed above the greenhouse, as well as the greenhouse that was built early. However, in recent years, the installation of fan wet curtains in high-grade potted greenhouses has continued to move downwards. Now in the greenhouse construction process, generally, the height of the fan is 1/3 below the seedbed, 2/3 is installed above the seedbed surface, and the wet curtain is installed from 30 cm above the ground. This installation is mainly based on planting on the bed surface. The actual temperature felt on the crop is designed. Because although the temperature at the top of the greenhouse is high, the foliage of the plant is not felt, so it does not matter. It is not necessary to spend unnecessary energy to reduce the temperature of the plant inaccessible area, and the fan is installed below the seedbed, which is conducive to the growth of the plant roots. .