Self-powered solar desalination using solar still enhanced by external solar collector and phase change material

The performance of a self-powered double-glass cover solar still with phase change material (PCM) connected to solar collector was studied. Black painted stainless-steel tubes filled with the required amount of PCM were placed at the bottom of the basin covering its surface area. Three modes of experiments were carried out al with cooling the glass cover: first, the solar still alone (SS), second: the solar still being connected to an external solar collector (SSC) and third: the solar still contains PCM and being connected to an external collector (SSCP). The effect of PCM type (sodium thiosulfate pentahydrate (STP), sodium acetate trihydrate (SAT) and paraffin wax (PWAX)) and its amount on the unit performance were investigated. The effect of hot water flow rate from the solar collector, solar radiation, ambient temperature and wind speed on the unit's performance were also investigated. The novelty of the work lies in combining the above techniques and parameters to improve the still productivity under set of controllable operating conditions. The experimental work was conducted in the months of May, June and July of 2019 in northern Jordan. During May, the daily productivity of the SS and the SSC modes were found to be 2.1 and 9.7 L/m(2). During July, the productivity was lower by 20% than that of May. The addition of PCM increased the productivity of the SSC system by about 50%. The type of PCM tested has no significant effect on the unit productivity. The addition of the external solar collector to the SS system unit increased the productivity by about 340%. The overall enhancement in productivity of SSCP reached almost 400% compared to that of SS unit.