Plant growth requires proper temperature and humidity. Correspondingly, the greenhouse needs ventilation system to regulate and control the indoor temperature and humidity, providing suitable growth environment for plants. Usually, the greenhouse ventilation system can be divided into two kinds of natural ventilation and forced ventilation. The so-called natural ventilation through the greenhouse to open the side windows or skylights, the use of greenhouse temperature difference between inside and outside or wind pressure to achieve convection inside and outside the greenhouse to reduce the greenhouse temperature and humidity. The so-called forced ventilation that is forced by the fan and other forced air convection inside and outside the greenhouse to adjust the greenhouse temperature and humidity. Two kinds of ventilation have their own characteristics, suitable for different situations.

       In order to achieve natural ventilation, people in the greenhouse side wall or roof windows. In general, the greenhouse side windows help to increase the ventilation around the greenhouse, but the open area is limited. Greenhouse skylights open the area will be much larger, and the hot air up, so the greenhouse skylights can more effectively increase the ventilation capacity of the greenhouse, is conducive to promoting the uniform temperature of the greenhouse.

       With the continuous expansion of greenhouse area, for improving the ventilation capacity of the greenhouse, skylights than the side window is much better. With the window system, the greenhouse side windows and skylights can be opened or closed as required. Greenhouse side windows are usually continuous windows, if the greenhouse covered with glass, PC boards and other relatively hard material, the use of continuous rack and pinion system drive; if it is soft materials such as film, you can use the film window system. There is also an option is to use inflatable window, that is, through the air bag inflated or deflated to achieve the closure of Poly window and open. Greenhouse skylights may be designed to be continuously open or intermittently opened along the greenhouse roof. In the case of continuous sunroofs, a continuous rack and pinion system is used, and each sunroof uses a continuous rack and pinion system. Multiple continuous sunroofs can also be opened and closed simultaneously with a split rack and pinion system, where the torque distributor on the windowing shaft is connected to the input shaft of the worm gear reducer, and a turbine worm reducer drives a skylight. When the skylight material is film, can also be used film film window system; if it is intermittent skylights, from the truss rack and pinion system, rocking rack and pinion system, column fixed rack and pinion system, choose one Drive System. One of the most common rack and pinion rack system, rocking rack and pinion system applications rarely, while the column fixed rack and pinion system is only the truss rack and pinion system in the drive shaft and gear moved to the greenhouse gutter below, reducing the Window system to block the incident light, which is a window system development trend.

       Greenhouse ventilation system is usually used low-pressure high-flow axial fan or circulation fan. Low-pressure large flow axial fan is mainly used to blow the greenhouse, or to the greenhouse outside the ventilation. The wind outside the greenhouse to avoid wind damage to plants in the greenhouse, and the greenhouse outside the air through the greenhouse to fill the gap throughout the greenhouse is conducive to the formation of a uniform greenhouse, air velocity moderate air flow, it should be widely used many. Circulating fan is a small flow of axial fans, and more for promoting the flow of greenhouse air is conducive to the greenhouse temperature and humidity uniformity, and promote the evaporation of plant leaf water. When the size of the greenhouse exceeds the effective working distance of the low-pressure and high-flow axial fan, the circulation fan can be used as a relay fan to ensure the effect of forced ventilation.

       In comparison, natural ventilation, low energy consumption, low noise, uniform ventilation, but the ventilation capacity around the greenhouse airflow, greenhouse temperature difference between inside and outside and other factors, fluctuations. Forced ventilation to consume a lot of power, fan noise and wind noise when running larger, the advantage of strong ventilation, ventilation time controllable. Therefore, if the greenhouse ventilation requirements are not high, consider the use of natural ventilation. Conversely, forced ventilation should be used.