Cfd study of airflow and microclimate patterns inside a multispan greenhouse

Abstract

Understanding and improving greenhouses requires the analysis and modelling of energy and mass exchange phenomena. The mastery of all these physical mechanisms can make it possible to propose technological solutions to control the greenhouse climate. This study presents an analysis and simulation of air flow, temperature and humidity patterns,in ½-ha multi-span greenhouse with oblique side walls,covered by insect proof nets.The site is located in the coastal area of southern Morocco. The fundamental calculation of climatic conditions is based on CFD, wich uses the mass, momentum and energy conservation equations. The dynamic influence of the insect screens and tomato crop on airflow movement, was described,using the concept of the porous medium approach proposed by Darcy and Forchheimer.The coupling of convective and radiative exchanges at the plastic roof cover is considered. A good agreement was observed between the measured and simulated values for inside air temperatures and relative humidity. Insect screens significantly reduced airflow and increased thermal gradients inside the greenhouse. The results clearly showed the heterogeneity of the greenhouse’s internal climate, which infects agricultural production in quantity and quality.