Reproduction of the Thermal Environment in the Greenhouse and Analysis of Exhaust Heat Effect at Different Aperture Rations of Roof Ventilation using CFD

Abstract

Computational fluid dynamics (CFD) analysis was used to model a single pipe house with a low eave height (less than 2 m), taking into account the effect of planting, and to reproduce the internal environment. As a result, it was possible to capture the temperature change of the internal air in both windy and windless conditions, while there was disagreement between the analyzed and measured values. The model was also used to estimate the relationship between the ratio of roof vent opening and the heat exhaust effect to reduce the internal temperature. The results showed that the smaller the roof vent opening ratio, the more heat was accumulated regardless of windless or windy conditions, and the larger the roof vent opening ratio, the higher the heat removal effect. However, this effect did not change significantly in the range of 12 and 16% of the floor area. This indicates that an aperture ratio of about 12% or more of the floor area is effective for ventilation of greenhouses with a similar shape.