LAUSR

Abstract The present study describes the effect of the surface cooling and thickness on the performance of the high temperature standalone tubular solar still (HTS-TSS). TSS is integrated with a parabolic concentrator solar tracking system (PCST). The test was performed under the climatic conditions of Hail city (27.64°N, 41.75°E) in Saudi Arabia. Results showed that reducing TSS tube thickness 40% enhances water productivity and efficiency by 21% and 13.35% respectively and lowers the cost of water production by 37.5%. Unlike conventional basin solar stills, results showed a negative impact on the HTS-TSS performance under tube surface cooling. Two different techniques of cooling were used. First technique is to spray cooling water over the whole tube surface at a rate of 10 ml every 30 min which reduces TSS productivity and efficiency by 10% and 7.79% respectively. In the second technique, cooling water flows in the gap between two concentric tubes with a rate of 40 ml/min which also reduces the productivity and the efficiency by 43.8% and 42.63% respectively. Cooling tube surface is not recommended for standalone TSS systems. Tube dimensions and properties are key design elements of TSS which needs more intensive investigations.