Modification of solar distillation unit to increase efficiency in drinking water production from saline water

Abstract

Solar distillation is one of the appropriate methods which could be used to reduce cost of power in the process of water purification. The commonly used single basin solar distillation systems are not efficient in the process of distillation. Therefore, an experiment was carried out to increase the efficiency of the existing single basin solar distillation unit constructed by the NERD center Sri Lanka by incorporating a 2cm thick unsieved river sand layer for heat retention due to its high thermal capacity. It was re vealed that, 30% increment of water distillation could be achieved when sand is incorporated to the so lar distillation system even though the internal temperatures of the both systems were not significantly different. Average daily production of the solar distillation system constructed by the NERD center was 1557ml/m2/day at Mapalana (6°3'39"N 80°33' 57"E). The average daily production after the modifica tion was 2017.50ml/m2/day at Mapalana. The maximum distillation rate of NERD solar distiller was 2150ml/m2/day and 2780mi/m2/day for the modified solar distiller during the experiment period. The average inner temperatures of NERD and modified solar distillers were 55.880C and 56.540C, respec tively when the average ambient temperature was 29.020C. Evaporation of more water from the modi fied solar distiller was the reason for insignificant temperature differences between two solar distillers.