Experimental investigation of stepped solar still with continuous water circulation

This paper presents a modification of stepped solar still with continuous water circulation using a storage tank for sea and salt water. Total dissolved solids (TDS) of seawater and salt water before desalination is 57,100 and 2370 mg/l. A comparison study between modified stepped and conventional solar still was carried out to evaluate the developed desalination system performance under the same climate conditions. The effect of installing a storage tank and cotton black absorber for modified stepped solar still on the distillate productivity was investigated. The results indicate that, the productivity of the modified stepped still is higher than that for conventional still approximately by 43% and 48% for sea and salt water with black absorber respectively, while 53% and 47% of sea and salt water, respectively with cotton absorber. Also, the daily efficiency for modified stepped still is higher than that for conventional still approximately by 20%. The maximum efficiency of modified stepped still is occurring at a feed water flow rate of 1 LPM for sea water and 3 LPM for salt water. Total dissolved solids (TDS) of seawater and salt water after desalination is 41, and 27 mg/l.