An experimental study on productivity, energy, and exergy efficiency improvement of inclined solar still using...

Water scarcity and clean drinking water remain a global challenge, particularly in remote and off-grid areas. Solar stills offer a low-cost, sustainable method for water purification. However, its low productivity and low efficiency are the major concerns for using it for large-scale applications. It provides low productivity because the evaporation and condensation rates in conventional solar stills (CSS) are limited by low heat transfer efficiency and large thermal losses. Wick materials increase surface area and heat transfer by dispersing water into a thin layer, which increases productivity and evaporation. Due to this, the proposed study aims to improve the performance of the inclined solar still (ISS) using different uncoated wick materials such as Flannel Cloth, Cotton Cloth, Coconut Coir mat, Jute, and Polypropylene materials. The performance enhancement without coating approach was used to avoid the additional cost, complexity, and maintenance associated with surface treatments or advanced material modifications in solar stills. Wick materials were used over the absorber plate without any coatings and compared with conventional ISS. Among the tested materials, the coconut coir mat provides the best performance. ISS with coconut coir provides water productivity of 4323 ml, whereas conventional ISS provides only 3303 ml. This water productivity of ISS with coir is 30.88% higher than that of conventional ISS. The average energy and exergy of ISS with coconut coir are 43.46% and 2.53%, which shows 62.40% and 86.02% higher energy and exergy efficiency compared to conventional ISS. The economic study gives the distilled water cost of $0.0131 for ISS with coconut coir, and this water production cost is 28.24% less compared to conventional ISS.