There is a scarcity of fresh water in many rural communities where solar stills can be used to produce drinking water at a minimal cost. These stills use solar energy, which is a sustainable form of energy, and hence this can contribute towards achievement of United Nations (UN) Sustainable Development Goals (SDG). This study aims to develop empirical models of a solar stills based on experimental data obtained at Werrington South, New South Wales, Australia. Two solar stills were used in the experiment, a conventional design (Con-Still) and a con-still modified with adding extra thermal mass inside the still (mod-still). Regression analysis was adopted to develop prediction equations using Pi (productivity in L/m2/day) as the response variable and ambient temperature (Ta), sky temperature (Ts19), global radiation (Gh), and wind velocity (W) as the predictor variables. The mean and median productivity values of the mod-still were found to be 17%, and 22% higher than that those for the con-still. The proposed mod-still can be further improved and used in rural areas to produce fresh water from sea water and other forms of contaminated water.

Solar desalination is the most attractive and simple technique for desalination process but suffers low thermal efficiency. The objective of this research is to study the effect of charcoal in seawater desalination for clean water production. The experiment was conducted in a basin type solar evaporator by using seawater with charcoal to seawater mass ratio variation of 1:50 to 1:500. The investigation was carried out for eight hours in sunny daylight. The water qualities including pH, conductivity, total dissolve solid (TDS), chemical oxygen demand (COD) and turbidity of the seawater and amount of evaporated water were determined. The spent and fresh charcoals were also characterized by using Nitrogen Adsorption (BET), X Ray Detector (XRD) and Scanning Electromagnetic Microscope (SEM). It is found that the addition of charcoal in the water leads to20 % increment of water temperature. Charcoal’s exposed area to the energy source significantly affects the temperature raise. The best charcoal to water mass ratio was achieved at 1:100 to produce 16.8% evaporated water. Charcoal was stable in seawater because minimum changes of pore size and pore volume were observed. In conclusion, charcoal is a potential salt adsorbent and medium for solar thermal energy storage for seawater solar desalination process.