An innovative floating solar still equipped with a Fresnel lens and a submerging condenser: An experimental study

• A novel design floating solar still with a Fresnel lens and a submerging condenser was investigated. • The overall efficiency of the still is remarkably enhanced with the Fresnel lens and submerged condenser. • A freshwater production of up to 18.85 L/day was achieved. • The daily average energy and exergy efficiency were 79.38% and 26.94%, respectively. In response to the scarcity of energy and clean water, extensive research on solar desalination systems has been carried out over recent years. Solar stills are a prevalent desalination system owing to their facile assembly and affordable cost. Nevertheless, solar stills are less productive than other conventional desalination technologies due to the challenge of raising the temperature of salt water. To address this, a newly developed floating solar still (FSS) with an air fan (AF), an external submerged condenser (ESC), and a Fresnel Lens (FRL), designated in short as (FSSFE), is experimentally investigated. This still boosts sunlight entering the still chamber and heats the saltwater directly via a Fresnel lens, thereby improving the evaporation. In addition to the Fresnel lens, an external condenser is integrated with the floating still, which is submerged in the surrounding aquatic environment. The findings reveal that the modified floating solar still with Fresnel lens and external condenser can produce significantly more clean water, accumulating roughly 18.85 L/day, a 469.48 % increase over the conventional solar still’s 3.31 L/day. The modified floating solar still offers a maximum daily average energy and exergy efficiency of 79.38 % and 26.94 %, while the conventional still offers only 20.31 % and 5.77 %, respectively.