Computational study of canary greenhouse side wall and roof vents opening effect on nocturnal airflow and climate patterns

The following paper presents a Computational Fluid Dynamic (CFD) comparative study ofthe effect of side wall and roofs vents openings on canary greenhouse airflow circulation andclimate distribution under different ventilation processes. The investigation was conducted ina one hectare canary greenhouse type, which is the most widespread type in the wholeMediterranean and along the Atlantic coast area of Morocco, especially in souss vally region.The simulations were performed with the commercial code CFD2000 based on the solution ofthe partial differential equations, which describe the flows, and was obtained by discretizingthe space and time and solving the transport equations on the spatial grid as differenceequations, used a finite volume discretization. The standard two equations k-ε model wasused to describe the turbulent transport. The influence of external factors such the covertemperature, the wind speed, on the flow was simulated by boundary conditions, these valueswere obtained from experimental results. Simulations were conducted with a fixed windspeed equal 1.05 m/sec, tomato crop rows oriented north-south and the ventilation openingsare continuous and equipped with insects screen type 20/10. Results reveal that ventilationopening arrangements strongly affects the greenhouse wind speed, which can generate aheterogeneous climate, especially during daytime. But in the other hand, results confirm thatthere is no significant effect of the side wall vents opening on canary greenhouse airtemperature and humidity fields.