Investigating the energetic, exergetic, and sustainability aspects of a solar still integrating fins, wick, phase change materials, and external condenser

Abstract

Renewable-based desalination systems as one of the sources of a chief human sustenance are of tremendous significance to tackle the climatic detriments associated with their fossil fuel-based counterparts. This experimental study deals with investigating a double slope solar still (SS) retrofitted with a combination comprising fins, phase change materials (PCM), external condenser (EC), and wick materials (WM). A comprehensive assessment of energy, exergy, economic, exergo-economic, exergo-environmental, and sustainability indicators have been carried out. Results reveal that the SS with all the mentioned modifications, i.e., fins, PCM, EC, WM (Case V) achieved the highest improvement of 32.46 % in daily productivity over the conventional SS (Case I) that achieved a daily baseline yield of 2.28 L/m2. Moreover, SS with fins (Case II), fins and PCM (Case III), fins, PCM, and EC (Case IV), and Case V exhibited respectively 3.49 %, 14.51 %, 28.21 %, and 39.36 % improvement in energy efficiency over the conventional case. Exergy analysis reveals that Case V achieved the maximum efficiency (5.26 %), which is 12.88 %, 25.84 %, 41.78 %, and 64.90 % more than Case IV, Case III, Case II, and Case I, respectively. The payback time for the different solar still configurations based on the energy and exergy analyses has been observed within the reasonable ranges of 0.81–1.23 yr and 10.22–12.64 yr, respectively. The exergo-economic parameter based on energy has been seen to be varying in the range of 62.15–69.39 kWh/$ while the cost of water varied within 0.0082–0.0095 $/L, with the least one attributed to Case V. This experimental investigation also substantiates the decrease in waste exergy ratio and the increase in sustainability index by the incorporation of fins and phase change materials with the traditional solar still.