Comparative study on conventional and phase change material (PCM) based solar desalination still using low-pressure water as a heat storage medium

Over the years, solar desalination is a renewable energy-driven method to produce freshwater from saline/ brackish water. Since solar radiation is available only in the daytime, many studies have been undertaken to store solar energy using phase change material (PCM). The aim of this study is to compare the two solar stills (still I as a conventional solar still and still II as a PCM-integrated solar still). In still II, using low-pressure water as thermal energy storage, PCM in a copper tube with a 1 liter capacity has been additionally installed than still I. Five trials have been conducted to compare the performance and yield between stills I and II, with various factors during the experiment. Remarkably, three distinct vacuum pressures - 712 mmHg (for trials 1, 2, and 3), - 690 mmHg (for trial 4), and - 660 mmHg (for trial 5) were used for the investigation to compare the performance of PCM-based solar still with conventional solar still among five trials. Finally, at a vacuum of -712 mmHg and 175 ml of water poured inside the low-pressure system, the distillate yield obtained from still II is 9.375% higher than the yield of still I.