Investigation to Improve Solar Still Productivity with using Solar Collector

Experimental study and theoretical analysis on the water desalination system of solar still have been investigated. Passive solar still of (80cm x 50cm) cm base area integrated with solar collector of five evacuated tubes with U-copper tube inside and PTC reflectors. The effect of solar collector, pump flow rate, heat transfer medium in the evacuated tube, and water level and their effect on the system performance with climate conditions have been studied experimentally. In the passive solar still the saline water fixed in the still and absorb the solar radiation, but in the active solar still the saline water pumped through U-copper tube in evacuated tubes to absorb more energy and back to the still. Results showed that: the productivity increased by 37.6% in case of using oil in the evacuated tubes at 2cm water level in the still, and increased by 53.8% at 3cm water level, so oil in the evacuated tubes represent the best medium as compare to air and water. Maximum percentage of increase in the productivity was 70.311% in case of 3cm water level, pump flow rate 3 L/m and oil in the evacuated tubes. The productivity of the active solar still increased by 6.65% when the pump flow rate increase from 1 to 3 L/m at 2cm water level, and increase by 2.35% at 3 cm water level. Maximum increase in the productivity was 236.826% in case of 3cm water level, pump flow rate 3 L/m and oil in the evacuated tubes. Increase the water level from 2 to 3cm reduce the productivity by 2% for the active solar still and 17.82% for the passive solar still. Maximum energy efficiency of the passive and active solar still were 32% and 53% respectively.