Experimental investigation on the effect of the slope of glass cover with flat and convex surfaces of absorber plate on the efficiency of the solar desalination

In this paper, the experimental results from the study of the effect of the angle of the slope of glass cover on the performance of the two geometry of solar desalination with flat and convex plates under different amounts of distilled water are presented. The slope of the studied angles is selected to be 25°, 27.5°, 30°, 32.5° and 35° while the other design parameters remain constant. The results showed that a solar collector with a convex absorber plate has a higher average daily water production compared to the solar collector with a flat absorber plate. Experiments also showed that the angle of the slope has a significant effect on the performance of the solar desalination system. The best slope is 32.5° and the larger angles cause to decrease in the heat transfer coefficient. These results can be used for design purposes and eliminate the common assumption of using lower angles to optimize productivity. Finally, from the obtained information, new experimental relations are obtained for the Nusselt number for the flat and convex surfaces with different slope angles of the glass cover.