The Position Angle of a Greenhouse Roof Vent

A greenhouse roof vent allows cool air to enter the house on warm days, reducing temperature and humidity levels inside. This allows for better crop growth. However, there are a number of disadvantages to using a roof vent.

The ventilation of the greenhouse window mainly depends on the wind and the difference between the indoor and outdoor temperatures. The prevailing summer wind blows from the windward side of the house, creating a pressure difference that causes air to flow towards the leeward side. This ventilation process is most efficient when the roof vents are oriented to match the summer wind direction. However, this effect is often reduced when the ventilation system is not complemented by side or end wall louvers.

Bringing Nature Indoors: The Beauty and Benefits of Greenhouse Windows

Moreover, the performance of the roof ventilation system is affected by the position angle of the greenhouse. Therefore, it is crucial to determine the optimum position angle of the greenhouse roof vents. In this article, the effects of a proposed front bottom + top and back roof (FTB) and a traditional front bottom + top (PW) ventilation structures on the airflow patterns and thermal behavior in an arched greenhouse are assessed using CFD simulation.

The results show that a roof vent with a position angle of 85° is the most suitable ventilation structure for an arched greenhouse to provide an effective cooling environment. The proposed design RS is found to be more favorable than PW with a position angle of 75° due to the improved interaction between the ventilation stack and the prevailing summer wind.