Performance Analysis Of A Tubular Solar Still Integrated With Phase Change Material For Sustainable Freshwater Production

Abstract

Freshwater scarcity is a global challenge that necessitates sustainable, low-cost, and decentralized solutions. Solar distillation offers a viable pathway to freshwater production, though conventional designs suffer from low efficiency and limited productivity. In this study, the performance of a tubular solar still (TSS) integrated with phase change material (PCM) was experimentally investigated and compared with a conventional tubular solar still (CTSS). Paraffin wax was selected as the PCM owing to its high latent heat capacity, thermal stability, and non-toxic nature. The PCM was encapsulated in copper cylinders and tubes and placed inside the basin of the modified still (MTSS). Experiments were conducted under natural solar conditions in June 2023, with key parameters including basin water temperature, vapor temperature, solar radiation, and hourly distillate yield being monitored. Results showed that the PCM-integrated still exhibited consistently higher basin and vapor temperatures, particularly during late afternoon and evening hours, when the PCM released stored latent heat. The MTSS achieved 32–38% higher cumulative yield compared to the CTSS, along with improved thermal efficiency in the range of 42–48%, as opposed to 28–30% for the baseline system. The integration of PCM effectively extended operational hours, reduced rapid cooling during post-peak periods, and provided more stable water production. These findings highlight the potential of PCM-enhanced tubular solar stills as a promising solution for decentralized freshwater generation, particularly in arid and semi-arid regions.