company news, news 03/06/2026 1
A greenhouse ventilation system refers to a mechanical assembly utilized within a greenhouse to open and close roof vents or side vents, employing either electric power or manual operation via a transmission mechanism. This chapter focuses primarily on the design of two electrically driven ventilation systems commonly employed in modern greenhouses: the rack-and-pinion system and the roll-up film system.
Greenhouse ventilation systems are primarily utilized to facilitate natural ventilation. Natural ventilation occurs when external wind is present; as the greenhouse structure obstructs the airflow, the air is forced to flow around the building, resulting in a variable distribution of air pressure across the greenhouse’s perimeter. On the windward side, airflow is impeded—causing a reduction in velocity and an increase in static pressure—whereas on the lateral and leeward sides, airflow velocity increases (often generating eddies) and static pressure decreases. This differential in static air pressure creates a pressure gradient between the interior and exterior of the greenhouse, known as wind pressure. Driven by this wind pressure, the internal air pressure on the windward side becomes lower than that of the exterior, while on the lateral and leeward sides, the internal pressure exceeds the exterior pressure. Consequently, external air enters the greenhouse through openings on the windward wall and exits through openings on the lateral or leeward walls, thereby completing the natural ventilation process.
Natural ventilation is indispensable for both the operation of a greenhouse and the cultivation of crops within it. It effectively regulates internal air temperature, humidity, and CO2 concentration, thereby meeting the specific environmental requirements necessary for the healthy growth of cultivated plants. Furthermore, the ventilation systems required for natural ventilation entail relatively low capital investment costs and minimal operational and maintenance expenses; moreover, they occupy a minimal amount of space and do not interfere with internal production activities.