Water Requirements of Basil in an Equipped Greenhouse with Heat Exchanger

A significant part of water consumption in greenhouses is related to the processes of evapotranspiration and cooling of the greenhouse. A large amount of water consumption in greenhouses is not used and in the form humid air is directed outside by the exhaust fans, which can be recycled by a heat exchanger and reused by the condensation process. It is also possible to use the exhaust air from the heat exchanger for cooling. Therefore, the purpose of this study was to investigate the effect of using the exhausted air from the heat exchanger, for cooling inside the greenhouse and on the water requirement of basil in two growing seasons. For this purpose, two greenhouses, one equipped with a heat exchanger and the other without the heat exchanger, were constructed with dimensions of 6×5 m2 and 2 meters in height. The results indicated that the greenhouse equipped with heat exchanger reduced the air temperature inside the greenhouse as compared to the greenhouse without the heat exchanger. In two growing periods, the average daily water requirements of basil for greenhouses equipped with heat exchangers and without heat exchangers were 2.53 and 3.26 mm in the first growing seasons and 2.19 and 2.81 mm in the second growing seasons, respectively, which showed significant difference between two greenhouses. In this study, the yield of basil in both greenhouses during the two growing periods was almost the same. Also, the yield in the second growing season in both greenhouses was lower than the one in the first growing seasons. Regarding the reduction of water consumption and the fact that a significant amount of water consumption can be recycled, the use of heat exchanger in greenhouses is suggested especially for tropical climate.