Principle
This is a cooling method that relies on natural pressure and temperature differences to achieve air exchange. When the temperature in the greenhouse rises, the density of the indoor hot air decreases and rises, and is discharged at the vents on the top or side of the greenhouse. At the same time, the colder air from the outside enters the room from the bottom of the greenhouse or other vents under the action of the pressure difference, thereby achieving the purpose of lowering the indoor temperature.
For example, after the greenhouse is heated up by sunlight during the day, the hot air will naturally flow out of the vents on the top of the greenhouse, just like the chimney effect, and fresh cold air will enter from the side windows.
Components
Vents: including side windows and skylights. Side windows are generally set at a lower position on the side wall of the greenhouse to facilitate the entry of cold air; skylights are located at the top of the greenhouse to exhaust hot air. The size, number and opening method (manual or automatic) of the vents will vary depending on factors such as the area of ​​the greenhouse and the needs of the crops grown.
Ventilation ducts: In some large greenhouses, ventilation ducts may be set up to guide air flow and make ventilation more uniform.
Scope of application
The natural ventilation cooling system is suitable for areas with a mild climate and a large temperature difference between day and night. In spring and autumn, when the outdoor temperature is more suitable, natural ventilation can well meet the cooling needs of the greenhouse. This cooling method is also more suitable for some plants that are more adaptable to temperature changes, such as some leafy vegetables.