COOLING METHOD IN GREENHOUSE

In the face of hot weather, if the temperature in the greenhouse is too high, it will cause various diseases to the plants. How can we reasonably control the greenhouse temperature?

Greenhouse cooling methods

1. Sunshade and cooling

At present, the most commonly used shading system in actual production is the cooling system. Shading can block excess sunlight outdoors, protect crops from strong light burns, and create suitable growing conditions for crops.
Different shading methods have very different shading effects. The most common one is to use shading nets. Its main function is to block strong light and reduce the temperature of the shed, and it is usually available in black and silver gray on the market.

The black sunshade net has a high shading rate and cools down quickly, and is suitable for short-term coverage in fields that require careful management in hot summer. The silver-gray sunshade net has a low shading rate and is suitable for light-loving vegetables and long-term coverage. In addition to distinguishing by color, it is also important to distinguish the material of the sunshade net.

2. Wet curtain fan cooling

The cooling method that utilizes the evaporation cooling principle of water and uses related equipment for ventilation to achieve cooling purposes is called a wet curtain fan. The wet curtain fan cooling system uses the evaporation cooling principle of water to achieve its cooling purpose. Although wet curtain fan cooling is cheaper than air conditioning, it also requires corresponding equipment.

When you need to cool down, just start the fan. The fan will forcefully pull out the air in the greenhouse, causing negative pressure; at the same time, the water pump will hit the water on the opposite wet curtain wall. When the outdoor air is sucked into the room by negative pressure, it can pass through the gaps in the wet curtain at a certain speed. When the air penetrates the wet curtain medium, the water and gas exchange with the surface of the humidified medium removes the sensible heat of the air. It is converted into latent heat of vaporization, causing the water to evaporate and cool down. The cold air flows through the greenhouse, absorbs the indoor heat, and then discharges it through the fan, thereby achieving the purpose of cooling.

3. Micro mist cooling

Micro-mist cooling is to spray water into the greenhouse in the form of micron-level or 10-micron level mist particles, causing it to evaporate quickly. It uses the large latent heat of evaporation of water to absorb a large amount of heat in the air, and then discharges the humid air outside to achieve the goal. Cooling purposes.

Although there is nothing unreasonable about mist cooling, this method will increase the humidity in the shed, so it is not suitable to use it if you encounter a "sauna day" in the north when the air humidity itself is relatively high. .
4. Natural ventilation and cooling

Generally, ventilation has three purposes - first, to remove heat and cool down; second, to remove moisture; third, to adjust the composition of gases in indoor air, remove harmful gases, and increase the content of CO2. In summer, indoor cooling is its main purpose.

Natural ventilation generally involves setting windows on the top or side walls of the greenhouse, relying on heat pressure or wind pressure for ventilation, and the amount of ventilation can be adjusted by adjusting the width of the window opening.

5. Spray cooling on the roof

Rooftop spray cooling is a cooling measure adopted by many farmers, but it also depends on their own water source conditions.

What needs to be noted here is whether the design of the sprinkler system is reasonable or not, which directly affects the water-saving effect. Generally speaking, the sprinkler system mainly includes: water source, pressurization (control) equipment, pipes and sprinklers.

6. Cooling with air conditioners and other equipment

What is the easiest way to cool down a greenhouse? I believe many friends will choose air conditioning. Indeed, in terms of dehumidification and cooling effects alone, using air conditioning equipment is the best. However, the cost of this method is relatively high. Currently, very few air-conditioning systems are used as greenhouse temperature control systems.