Experimental investigation of stepped solar still with external condenser and heat energy storage

Nowadays solar still is widely used in solar desalination processes. This work presents a modified stepped solar still with 7 steps 35 mm high, 80 mm wide and 600 mm long and external condenser. Phase Change Material is used as a heat storage source to continue to sweeten saline water after sunset. In this study, stearic acid has been used as phase change material. In order to increase the efficiency of the still, a fan has been used to suck the air in the stepped solar still and transfer it to the condenser. The experiment was carried out in four modes: the first mode was simple, the second mode was only with the fan and the condenser, the third mode, with stearic acid as phase change material, and the fourth mode was used simultaneously with the PCM and external condenser. The results show that the maximum productivity was obtained in fourth mode of experiment which is increased 104%.