Assessment of different passive solar stills via exergoeconomic, exergoenvironmental, and exergoenviroeconomic approaches: A comparative study

In this study, comparative performance assessment of different passive solar stills systems based on energy matrices, exergy, economic, exergoeconomic, environmental, exergoenvironmental, enviroeconomic, and exergoenviroeconomic viewpoints is performed. Six systems of passive solar stills are considered namely, traditional solar still (TRD still), solar still with phase change materials (PCM), solar still with PCM embedded in a pin fin heat sink (PCM-PF), solar still with PCM incorporated with steel wool fibers in the basin (PCM-SWF), solar still with SWF only in the basin (with SWF) and finally solar still with pin fined heat sink in the basin (with PF). The performance of the six systems is experimentally evaluated and compared to each other under the same meteorological conditions of New Borg El-Arab City, Egypt (Longitude/Latitude: E 029 degrees 42'/N 30 degrees 55'). The results indicated that PCM-based solar stills systems performed poor performance based on energy matrices, freshwater production cost, exergoeconomic, exergoenvironmental and exergoenviroeconomic parameters. Whereas, solar still with SWF gives the highest performance among all studied systems by employing these enhanced (exergy/economic/environmental) approaches. The daily energy and exergy outputs for conventional still are the minimum at 2.5 and 0.1528 kWh/day, respectively and still with SWF are the maximum at 2.856 and 0.1869 kWh/day, respectively. The annual amount of CO2 emission mitigated for conventional still, still with PCM, still with PCM-PF, still with PCM-SWF, still with SWF and still with PF are 33.02, 35.88, 38.26, 37.05, 41.6 and 38.35 tons, respectively based on energy approach. Whereas, the corresponding values based on exergy are 0.961, 0.6652, 0.6217, 0.756, 1.56 and 1.189 tons, respectively.