Numerical investigation of a naturally ventilated greenhouse containing stacked benches

Abstract: The rapidly growing concerns of energy efficient methods have increased the emphasis on natural air ventilation in indoor environments such as greenhouses. Naturally ventilated greenhouses are used to create a microclimate that does not fluctuate majorly with the ambient conditions. This microclimate is of vital importance since it directly influences the quality and quantity of crop production. This study investigates the natural ventilation in a single-span greenhouse with a roof vent opening configuration using a two-dimensional Computational Fluid Dynamics (CFD) model. The numerical model is first successfully validated against data found in a study by Ould Khaoua. The two benches are then replaced by stacked type benches in order to investigate its effect on the indoor climate inside the greenhouse, which is the main objective of this study. The temperature and velocity profiles at the various stack heights were observed and it is noted that the temperature distributions are not significantly affected by the type of benches. However, the air velocity values are seen to be significantly lower for the lower racks when stacked benches are used. This indicates that care should be taken when placing plants on the lower racks as this could lead to non-uniform crop production