ISHS Acta Horticulturae 559: V International Symposium on Protected Cultivation in Mild Winter Climates: Current Trends for Suistainable Technologies
NATURAL VENTILATION OF MULTI-SPAN TUNNEL GREENHOUSES WITH AND WITHOUT INSECT-PROOF SCREENS |
| Authors: | P. Muñoz, J.I. Montero, A. Antón |
| Keywords: | leeward, windward, discharge coefficient, greenhouse, ventilation, screens |
| Abstract:
In this paper, the ventilation rate of a multispan plastic greenhouse was analysed, and the effect of insect-proof screen was evaluated. Direct measurements of the ventilation rate of a three-span greenhouse with continuous roof vents were obtained by means of the decay rate tracer gas method, with and without screen. Empirical regressions between ventilation rate and wind speed were established for both cases. The screen had a negative effect on the ventilation rate. In most cases, the air exchange rate of screened greenhouses with continuous rectangular roof vents was not sufficient to ensure suitable environmental conditions. It was also shown a clear effect of wind direction on the air exchange process, the ventilation rate being higher when the wind was facing the opening. | |
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