Analyzing solar still performance with PV electricity storage: Energy, exergy, exergoeconomic, and enviroeconomic perspectives
Ayman Refat Abd Elbar, Faisal B. Baz, S.A. Marzouk, Ayman Eldesoukey, Ahmed M. Salem
Abstract
Population expansion and water shortages are driving up demand for freshwater worldwide. This study presents an in-depth 4E analysis (energy, exergy, exergoeconomic, and enviroeconomic) of a novel solar still (SS) design integrated with a photovoltaic (PV) module. In this configuration, the PV module is positioned on the backside of the SS, enabling electrical output to be stored during daylight hours and converted to thermal energy after sunset to heat saline water in the SS basin until midnight. Two solar still configurations are assessed: a conventional solar still (CSS) and an enhanced design featuring the PV module (CSS + PV). This integration not only optimizes land use by requiring no additional space but also enhances efficiency as the PV module acts as a reflector, transferring additional solar energy to the SS basin. Results demonstrate that the CSS + PV setup boosts the SS temperature by nearly 23 %, significantly increasing hourly freshwater production, particularly around midday, with a 52.3 % increase in daily freshwater yield over the CSS alone. Energy efficiency shows a steady increase until mid-afternoon, followed by a dip and subsequent rise into the evening, with CSS + PV consistently achieving higher efficiencies. The CSS + PV system also yields substantial gains in exergy, with day-to-day exergy efficiency improving by 20.12 % compared to conventional stills. This study underscores the potential of PV-integrated SS systems to enhance performance across multiple metrics, supporting their suitability for sustainable freshwater production and offering a viable solution for increased water and energy efficiency.