Performance Investigation on a Double-Slope Passive Solar Desalination System Targeting towards Sustainable Development of Oman

In recent times, academicians and scientists have developed many methods for purifying saline water into pure water that is suitable for drinking, as well as other suitable applications. Fortunately, solar desalination has been a very popular technique, which uses eco-friendly solar energy. In this work, a passive-type double-slope solar still was designed and fabricated according to the Global Positioning System (GPS) coordinates of Nizwa city in Oman. Economically and readily available materials, such as acrylic, glass, and foam insulation materials, were used in the construction of the double-slope solar still in addition to the conventional materials used for the supporting structure of the solar still. The climatic factors (such as the solar radiation and ambient temperature), design factors (such as the exposure surface area, inclination, insulation material and thickness, and glazing material), and operating parameters (such as the glass temperature, feed water temperature and yield) obtained were considered in the study to estimate the performance of the solar still. DHT 11 sensors with Arduino programming were used in the experiment to record the temperatures at specific locations on the solar still daily with regular time intervals for a period of 3 to 4 weeks. The solar still was designed to operate from February to March 2023. The temperatures were recorded every two hours daily, whereas the yield was recorded at the end of the day of operation. The quality of the yield was estimated through the measurement of pH and TDS (Total Dissolved Solids) values. The energy and exergy analysis of the desalination unit was carried out to estimate the thermal performance of the system. A significant effect of solar intensity and ambient temperature was observed on the thermal performance of the system and on the quality of the drinking water. An energy efficiency ranging between 30 to 45% and exergy efficiency ranging between 2 to 3.5% was obtained in the system, which was reasonably better for a thermal system involving a renewable source of energy.