EFFECT OF VENT TYPES AND INSECT SCREENS ON VENTILATION OF “PARRAL” GREENHOUSES

A study was carried out at the Experimental Station Las Palmerillas of Cajamar with the aim of characterising the natural ventilation of the “parral” greenhouse.
For this purpose the ventilation rate for two different types of roof ventilators (rolling and flap windows) was determined.
Natural ventilation rate was measured in a symmetric multispan (5 spans) “parral” greenhouse with polyethylene cover by means of the dynamic tracer-gas method (decay rate method), using N₂O as tracer-gas.
For rolling openings, no influence of the position of the window in the span (leeward or windward) on the ventilation rate was observed.
For flap windows, windward ventilation was found to be around 50% higher than leeward.
Flap windows have proved to be much more efficient than rolling windows for wind induced ventilation.
In the same way, we have found and important reduction of the ventilation rates due to the presence of an anti insect screen in the openings.

VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation

J. Pérez Parra, E. Baeza, J.C. López, C. Pérez, J.I. Montero, A. Antón

tracer gas, windward, leeward, wind velocity, ventilation rate, symmetric multispan greenhouse.

https://doi.org/10.17660/ActaHortic.2003.614.59