ISHS Acta Horticulturae 691: International Conference on Sustainable Greenhouse Systems - Greensys2004
EFFECT OF VENTILATOR SIZE ON NATURAL VENTILATION IN PARRAL GREENHOUSE BY MEANS OF CFD SIMULATIONS |
| Authors: | E.J. Baeza, J. Pérez-Parra, J.I. Montero |
| Keywords: | CFD, natural ventilation, ventilator, parral greenhouse |
| Abstract:
In the province of Almeria, the most important in Spain for protected horticulture, there are approximately 26,000 ha of “parral” greenhouses (Sanjuan, 2000). One of the main problems in this greenhouse type is the lack of natural ventilation which can be explained by different factors being the insufficient ventilator area one of them. The aim of this paper is to evaluate the effect of ventilator size on the air exchange rates of two 5 and 10 spans parral multispan greenhouses using CFD. The two most common types of roof ventilators in the parral greenhouse (rolling vents and flap vents) have been evaluated. A two dimensional model of the greenhouse was generated. In a previous step, CFD simulations were validated with tracer gas experimental data measured in the experimental greenhouse. A clear influence on the air exchanges was observed when the width of the openings was increased. Flap vents with increased size proved to be more efficient than rolling vents and provided ventilation rates for middle wind velocities which were close to those proposed as optimal in the literature. | |
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