Thermo-economic comparison of single basin and stacked solar still configurations

Owing to the low productivity per unit area of a single basin solar still, a stacked solar still configuration which has two basins stacked together has gained popularity due to its increased output for the same area. This paper delivers a detailed comparison between single basin and stacked solar still configurations based on thermodynamic and economic analysis. A single slope single basin and double basin solar still of same base area of 0.5 m² were fabricated and tested at Velammal Engineering College, Chennai, in the month of March 2020. The average daily productivity obtained from the single basin and stacked still configuration are 1.416 L/day and 1.913 L/day, respectively. The thermo-economic analysis gives detailed information about the exergy destruction of each component of the solar still and the overall exergy efficiency of both the configurations. The energy and exergy efficiency of the stacked solar still is higher than the single basin solar still due to lower energy loss in the stacked solar still configuration. In order to optimize the cost of the distilled water, an economic feasibility analysis is carried out, and it is observed that the cost per liter of distilled water produced from a single basin solar still is 29.9% higher than the stacked solar still. The payback period of the stacked solar still is 540 days, whereas it is 459 days for a single basin solar still. The results from the analysis further justify the thermo economic feasibility of a stacked solar still.