Productivity, thermal, and exergy efficiency analyses of tubular solar still integrated with solar water heater

Productivity is the primary output of any solar still system, hence solar still technology needs to be improved continuously in order to reduce the price of distillate water. In the current work, we compared the tubular solar still (TSS) with the conventional solar still of the same size and material while conducting experiments and improving performance when implementing a solar water heater. The experiment was conducted in Nagpur, India, in May 2022, at Longitude 21.124419, Latitude 79.002072. Three different water depths, respectively, 1 cm, 2 cm, and 3 cm, were used in the experiment to compare TSS using active solar still with TSS using passive solar still. As part of the investigation, the TSS solar water heater produced the most freshwater, at a rate of 8.76 L/m(2), compared to the CTSS solar still, which produced 6.02 L/m(2) of water at a depth of 1 cm. For water depths of 1 cm, 2 cm, and 3 cm, respectively, the ATSS increased freshwater highest production at 1 cm depth by 45.51%, in comparison to the CTSS. The costs of producing freshwater, ATSS and CTSS, are 0.015 $/L and 0.011 $/L, respectively. As compared to ATSS, the exergy and thermal efficiency of CTSS at 1 cm of water depth is increased by 130.32% and 24.90%due to the absorber area which is inversely correlated with the hourly thermal efficiency, and the absorber area directly correlated with the still output for the exergy efficiency.