Exergy, energy, and economic analyses of pyramid solar still integrated with solar water heater

Abstract

ABSTRACT One of the top priorities in the development of solar stills is productivity enhancement. The present study experimentally investigates both passive and active pyramid solar stills. In active mode, the pyramid solar still is integrated with a solar water heater. The tests were carried out with conventional pyramid solar still (CPSS) and active pyramid solar still (APSS) at 1, 2, and 3 cm of water depth, respectively. The experimentation has been carried out in Nagpur (Longitude 21.124042, Latitude 79.002211) from April – May 2022. The finding shows that the pyramid solar still coupled with a solar water heater at a water depth of 1 cm produces the highest productivity of 7.99 L/m2.The hourly thermal efficiency is to be inversely related to the absorber area and the exergy efficiency is inversely related to the absorber area and directly proportional to the still output. Hence exergy and thermal efficiency of CPSS at 1 cm water depth is enhanced by (107.59%) and (49.36%) as compared to APSS, respectively. The cost per liter of fresh water obtained from conventional pyramid solar still and active pyramid solar still are 0.0139$/L and 0.00751$/L respectively. Based on the study, lower basin water depths and secondary heating enhance the solar still’s productivity.