Keywords: single slope solar stills, annual performance, floating porous absorbers, capillarity, thermal inertial, nocturnal output, start–up, operating temperatures, jute cloth, thermo–col insulation, base heat losses, distillate, basin water, renewable energy, surface temperature, evaporation rates, wind speed
Multiple floating porous absorbers type solar still: annual performance evaluation
This paper describes an experimental work conducted in order to evaluate the annual performance of a modified single sloped basin type solar still. The modified still consists of a multiple number of blackened porous jute cloth absorbers, which are being floated on the basin water with the help of thermo–col insulations. Higher absorber surface temperatures are rapidly reached in this design, resulting in a quicker start–up and faster evaporation rates. Cooler basin water results in lower base heat losses. Highest distillate output was recorded in the month of May with 52% efficiency, whereas the lowest was obtained in the month of December with 34% efficiency. The modified still gave the maximum gain of 74.6% more output in the month of January and the minimum gain of 35.5% in the month of August, when compared with the conventional still. An average 7.6% of the total output was obtained as nocturnal yield. The productivity initially increases marginally with the wind velocity, but at higher wind velocities it decreases rapidly. Extra base insulation improves the performance.