High performance of a simple design, two effects, solar distillation unit

Abstract

Under a passive mode of operation, a transient analysis of a new, simple design, two effects, solar distillation unit is presented. The unit consists mainly of a single sloped basin solar still of a shutter fashion type reflector, purging its vapor to a second effect still connected at the shaded side of the first effect still. Based on energy balance for the different components of the two effects distillation unit, hourly variations in the unit energies, temperatures, productivity and efficiency were obtained. The effects of some design, operational and environmental parameters on the distillation unit productivity are presented. On the basis of the numerical computations, it was observed that the unit first to second effects volume ratio, solar intensity, base and side wall insulation and initial temperature of the basin water significantly influence the unit's productivity. The daily productivity increases to a high as 10.7 kg/m 2.day for the proposed unit under the climatic conditions of Dhahran, Saudi Arabia. The proposed distillation unit is simple, passive and adds no design, operation or maintenance complexities over the conventional single effect basin solar still.