ISHS Acta Horticulturae 287: II International Symposium on Protected Cultivation of Vegetables in Mild Winter Climates
ADIABATIC AIR COOLING FOR IMPROVEMENT OF THE DIURNAL CLIMATE IN GREENHOUSES UNDER DESERT CLIMATE |
| Authors: | H. Verlodt, B. De Muynck, A. Mougou |
| Abstract:
Standard plastic greenhouses of the hemispheric type were equipped with static evaporation systems hanged up at 2 m of height in the greenhouse. The evaporation system was composed of curtains which were wetten by means of incorporated Irrigaine or Portube irrigation tubes. Climatic data were measured under this greenhouses and compared to control greenhouse and outdoor data. Under improved aeration conditions (16% of ventilation openings) the temperature under the greenhouse cultivated with watermelon and equipped with the wet curtains are 5° C lower than under the control greenhouse with the same aeration system and mostly proach to the outside temperatures. Under poor ventilation conditions (7% ventilation openings) the temperature decrease is reduced to 2–2.5° C. Relative humidity under greenhouses with improved ventilation and static evaporation is in most cases 15–20% higher than under the control greenhouses, while with classic ventilation the differences with the control are reduced to 10–12%. Enthalpy under both greenhouses is similar, showing the adiabatic way of the cooling effect. Theoretical water consumption to realize the adiabatic cooling is calculated and compared with the water consumption of the evaporation system. In greenhouses with young tomato plants the utilisation of 4 wet curtains fixed on Portube irrigation systems permitted to obtain an important reduction of greenhouse temperature and only a slight improvement of relative humidity. The reason of this differences are discussed. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
