Effect of crops on natural ventilation in a screenhouse evaluated by CFD simulations

J. Flores-Velazquez, W. Ojeda, F. Villarreal-Guerrero, A. Rojano
Screenhouses are one of the most important production systems in the Mexican horticulture industry. They are rising in extension along with low technology structures (53%) compared to typical plastic cover greenhouses (47%). One of the main reasons is the average temperate conditions prevailing in wide regions in Mexico dedicated to crop production, as well as the chance for avoiding the high cost for installing heating or ventilation systems. Under the screenhouse technology, tomato is the main crop occupying 78-80% of the surface area, followed by sweet pepper (10-12%) and cucumber (2-4%). Normally, a screenhouse is suitable for its installation under semiarid conditions; however, its management is based on traditional greenhouse knowledge. Therefore, more studies are needed on the behavior of these production systems. In this study, CFD is used for analyzing the thermal behavior in a big scale screenhouse by using the classical k-e method. Four different sequential crops and mesh porosities were simulated. Preliminary results indicated not significant differences in the ventilation rate. The spatial thermal distribution was similar regardless of the crop, the leaf Area Index and the mesh porosities employed in the simulations.
Flores-Velazquez, J., Ojeda, W., Villarreal-Guerrero, F. and Rojano, A. 2017. Effect of crops on natural ventilation in a screenhouse evaluated by CFD simulations. Acta Hort. (ISHS) 1170:95-102
air exchange, drag coefficient, CFD, thermal gradient, turbulence model

Acta Horticulturae