Supply of Greenhouse Water Requirement from Solar Distiller Freshwater Production Using Condensation Method

In this research, a greenhouse connected to a solar distiller device was constructed for the desalination of saline water and irrigation at Shahid Chamran University of Ahvaz. Sand, sand-bagasse-perlite, and bagasse-perlite beds were used in the greenhouse as a condenser of hot and humid air of the distiller tank. By measuring air temperature, relative humidity, air flow velocity in the distiller tank, temperature around the pipes and moisture in the beds, daily production of freshwater from the distiller was calculated. The FAO Penman-Montieth method was used to estimate greenhouse reference evapotranspiration. The purpose of this research was to estimate the percentage of supplied evapotranspiration in the greenhouse by produced freshwater from the condensation method and to select the proper condenser bed in terms of moisture and temperature distribution. Daily and periodic measurements of freshwater produced by each bed were compared to daily and periodic evapotranspiration of the greenhouse. The average amount of freshwater produced per square meter by the solar distiller was calculated to be 1.23, 1.97, 2, and 1.97 kg/day in May, June, July, and August, respectively, with the average of 1.75 kg/day during the whole period. The average evapotranspiration amount in the greenhouse was estimated to be 4.08 millimeter per day. Production water in sand, sand-bagasse-perlite and bagasse-perlite beds was calculated to be 0.94, 0.79, and 0.82 times of the evapotranspiration rate within the greenhouse, respectively. Due to the lower temperature of the sand bed and the higher production of water, the sand bed is a better condenser than the other two beds. Evapotranspiration from April 21 to July 29, 2018, was estimated to be 408.2 millimeters, which %85 of it was supplied by a distiller with a production of 2799.5 kilograms for an area of 8.1 square meters of bed (without considering its type).