EFFECTS OF THREE COOLING SYSTEMS ON THE MICROCLIMATE OF A GREENHOUSE WITH A PEPPER CROP IN THE MEDITERRANEAN AREA

Control of the greenhouse microclimate during the summer is an important challenge in warm climate areas.
Different cooling systems allow the limitation of high temperatures and/or low relative humidity levels inside the greenhouse. In the present work the microclimate conditions in three greenhouses with the same pepper crop and three different cooling systems were determined: T1 with mechanical ventilation; T2 fog system and natural ventilation and T3 plastic whitening with natural ventilation.
The largest differences, between the systems, were found in the first weeks after transplanting, when plants had a low leaf area index (LAI<1) and high temperatures occurred outside the greenhouse.
The maximum temperature differences (weekly average of maximum temperatures) between inside and outside the greenhouses, were 8.4°C for T1, 4.1°C for T2 and 5.1°C for T3. The maximum vapour pressure deficit values inside the greenhouses were 4.1 kPa for T1, 3 kPa for T2 and 3.7 kPa for T3. To maintain the assigned climate settings, the fog system consumed 138 L m^-2 of water and the electricity consumption of the forced ventilation system was 9.3 kWh m^-2 (growing cycle from 21^st July 2004 until 6^th March 2005). As the final yields were very similar in the three treatments (no significant differences were found), we can consider that whitening of the plastic cover as the most efficient cooling system in terms of water and energy use.

XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation

J.C. Gázquez, J.C. López, J.J. Pérez-Parra , E.J. Baeza , P. Lorenzo , I. Caparros

greenhouse, whitening, forced ventilation, evaporative cooling

https://doi.org/10.17660/ActaHortic.2012.927.92