Study on the use of cooling water as input water to improve double slope solar still performance

The problem for residents in island and coastal areas is the lack of fresh water, especially during the dry season. In the dry season, there is abundant potential for solar energy utilization. This potential can be utilized as an energy source for distilling seawater into fresh water using solar still technology. Solar still performance is influenced by the evaporation and condensation processes. Several researchers have made efforts to increase evaporation, such as enhancing the heat absorption of absorber plates and preheating seawater. This research aims to apply initial heating to seawater to enhance the evaporation process. The initial heating of seawater is obtained from heat absorption in the walls, which function as a cooling medium. Thus, this research aims to investigate the use of cooling water on the walls as input water to enhance the performance of double-slope solar stills. The research was carried out experimentally and theoretically. Research on the performance of a double-slope solar still utilizes wall cooling water as input water (SSDS.WCW.HC) compared to wall water cooling (SSDS.WCW). The research yielded an average daily condensate water productivity using SSDS.WCW.HC experimentally of 3.48 kg/10-hours and theoretically of 3.56 kg/10-hours, which is higher compared to SSDS.WCW experimentally of 3.16 kg/10-hours and theoretically of 3.27 kg/10-hours. The average daily energy efficiency using SSDS.WCW.HC experimentally is 53.77 % and theoretically 54.83 % higher compared to SSDS.WCW, which is 48.87 % experimentally and 49.81 % theoretically. The highest daily average exergy efficiency using SSDS.WCW.HC was 6.44 %, compared to 5.33 % for SSDS.WCW