Investigating the Possibility of Water Production from humid Air in the Greenhouse Model Equipped with Heat Exchanger

About 90 percent of the water used in greenhouses is allocated to the two processes of evapotranspiration and cooling of the environment. A large amount of water used in greenhouses is driven out useless in the form of humid air by the fan, which is recyclable and can be reused in the greenhouse water inlet cycle by condensation. Therefore, the purpose of this study is to investigate the possibility of water production from humid air exiting the greenhouse. In the next step, the effects of heat exchanger length and inlet air velocity were investigated on the amount of recycled water. This study was conducted in 9 experimental treatments with three lengths (0.5, 1 and 1.5 m) and three inlet air velocities (0.5, 0.8 and 1.2 m/s) inside a greenhouse model with dimensions of 2x1.5 x 2 m3. The measurements were done with dimensions of 1.5 × 1 × 2 m3. The results showed that increasing the heat exchanger length and inlet air velocity increase the water production and the highest condensed water achieved at heat exchanger length of 1.5 m and an air velocity of 1.2 m/s. Also, the amount of water produced was about three times higher than normal condition without condensation, up to a maximum of 60 liters at a length of 1.5 m and velocity of 1.2 m/s. The results showed that about 10 to 30 percent of the water used for irrigation and cooling (fan and pad) the greenhouse can be recovered by using a heat exchanger.