How to cool down in midsummer? A detailed guide to dealing with high temperatures

The heatwave and high temperatures of midsummer makeorchidsenter an unbearable season, and it is alsoorchid growinga time when people's hearts burn like fire. How to cool down isorchid growinga topic that people often discuss. By consulting relevant materials, drawing on others' experience and doing some experiments myself, I have a few insights to discuss with fellow orchid growers. Please offer your valuable suggestions. 1. Water mist cooling Water mist can absorb a large amount of heat in the air. According to relevant data, for every one kilogram of water excited into a floating state of artificial fog, the effect obtained equals dissolving seven kilograms of ice. Water changes from liquid to gaseous state, which increases air humidity and achieves the purpose of lowering air temperature. The whole process is an isenthalpic process. What can produce water mist is nothing other than compressed spray and ultrasonic atomizers. Compressed spray uses pressure to force water through a nozzle to produce an atomizing effect, or uses a centrifugal pump to generate strong air pressure that splashes water into tiny droplets of 0.01-0.03mm to produce an atomizing effect. The mist produced by this kind of atomizer is relatively large and the cooling effect is also relatively obvious, making it more suitable for large orchid sheds. However, because its compressor power is relatively large and the mist droplets produced are relatively large, the cooling persistence is not very good, and it often needs to be turned on frequently, which brings unnecessary humidity to the orchid room. Ultrasonic atomizers use the principle of high-frequency oscillation to make water produce tiny droplets of 0.5 microns and become atomized. The water particles of this atomizer are tiny and easily penetrate into the air, giving a relatively good cooling effect. Turning it on frequently will not bring high humidity to the orchid room. Because the atomization amount is not large, it can only be used in small areas. The micro-mist system currently often used in modern greenhouses has a very good effect. It has both a very large atomization amount and tiny mist droplets, and its cooling and humidifying effects are relatively ideal. 2. Wet curtain cooling The wet curtain cooling system is composed of a special paper porous wet curtain, a water circulation system and a low-pressure, high-flow energy-saving fan. The wet curtain and the fan are installed respectively on the two gable walls of an enclosed building. When the fan draws air, it creates negative pressure indoors, forcing unsaturated outdoor air to flow through the porous moist surface of the wet curtain, causing water to evaporate and absorb a large amount of latent heat, thereby lowering the temperature of the air itself. When the wet curtain fan cooling system operates, it will continuously introduce low-temperature air after evaporative cooling into the room for cooling, thereby forcing the dry-bulb temperature of the air entering the room to drop by 8-12°C and continuously introducing it into the room for heat relief and cooling. It can also maintain air humidity. 3. Roof sprinkling cooling Roof sprinkling cooling is to evenly spray water on the roof surface of a glass greenhouse to lower the temperature of the greenhouse. Its principle is: when water flows on the glass roof surface, the water exchanges heat with the glass roof surface of the greenhouse, taking away the heat inside the greenhouse. Because the thermal conductivity of water is far greater than that of air, the heat exchange intensity between water and glass is far greater than that between air and glass. In addition, when the water film thickness is greater than 0.2 mm, all the energy of solar radiation is absorbed by the water film and carried away, which is also equivalent to shading. Roof fountain sprinkling cooling requires a water source with relatively low temperature. Its cooling effect is related to the water temperature and the flow of water on the roof surface. In principle, if the water is distributed relatively evenly on the roof surface, the cooling effect can reach 6°C to 8°C, but current actual practices cannot reach this ideal situation, and generally can only reduce the temperature by 1°C to 2°C. The disadvantage of roof fountain sprinkling cooling is that it consumes a large amount of water, water scales form on the roof surface, affecting the light transmittance of the glass, and cleaning is complicated. 4. Other cooling methods Air conditioning cooling: this cooling method can make the temperature reach as low as 18°C and the cooling effect is long-lasting, but poor ventilation and poor humidity are major weaknesses of air conditioning cooling. Natural ventilation and forced ventilation cooling effects are not very ideal, because in hot weather the air is also hot, and the gas blown ontoorchid plantsis likewise hot, but the air is relatively fresh. Shade cooling is a means of affecting the sunlight transmittance and blocking sunlight to achieve the purpose of cooling. It has an obvious effect, but the temperature drop is not large. Evaporative cooling: through the evaporation of water absorbing heat to produce a cooling effect, usually by setting up water troughs or splashing water.