Thermo-economic performance improvement of hemispherical solar still using wick material with V-corrugated basin and two different energy storage materials

Abstract

Solar still is a developing solar desalination method that has been introduced to face the shortage of freshwater with low energy consumption. However, this method is challenged by its low productivity. Therefore, the following work aimed to improve the freshwater productivity and reduce the produced water price. Herein, the performance of a hemispheric solar still equipped with four alternative combinations was experimentally studied; and its thermo-economic performance was assessed. The experimental work had four stages, firstly the distiller’s flat basin was replaced by a V-corrugated basin. Secondly, the corrugated basin was covered with a black cotton wick material. Thirdly, paraffin wax, as a phase change material (PCM), was contained under the wick-coated corrugated basin for latent thermal storage purpose. Finally, paraffin was replaced with sheep fat PCM. Each modified distiller was compared to a conventional one from 8 A.M. until 9 P.M. under the climate conditions of Suez City, Egypt lies at (29. 5825 °N, 32.5734°E) in terms of the thermal performance, daily productivity, and freshwater price. The four cases showed increasing in the daily productivity by ratios of 11 %, 25.7 %, 34.1 %, and 39.6 % respectively. The fourth case showed the best water productivity and thermal performance. It had daily productivity of 4737.5 mL/m2 and 45 % thermal efficiency. Furthermore, the thermal performance in terms of the thermal and exergy efficiencies improved by 39.75 % and 44.04 %, whereas the average total heat transfer coefficient increased by 5.5 %. Moreover, the freshwater price was 0.0137 $/L, likewise, 17.5 % cost reduction.