Design, optimization and performance evaluation of water-energy nexus of an atmospheric water harvesting system (AWHS) based on subsurface cooling and solar power

The scarcity of drinking water is one of the most important challenges worldwide. There are many methods for producing and purifying water. Given the large amounts of water vapor in the atmosphere, the potential for converting water vapor into usable water can be an important source of water harvesting. High energy consumption and low condensation rate are one of the biggest challenges in producing drinking water by air moisture harvesting. The use of an atmospheric water harvesting system (AWHS) using subsurface cooling and solar-powered underground coils for air moisture harvesting have assessed in this study. The results have shown that the use of underground coils in the warm seasons of the year can provide the dew point temperature required for water condensation. The parameters affecting the water performance and energy consumption of the AWH system based on underground coils have evaluated. By choosing an inlet air velocity of 0.5 m/s, a coil perimeter of 0.82 cm, and a coil length of 14 m (which includes four inlet and outlet coils), the system was able to collect a maximum water of approximately 23 lit/day. Also, the comparison of the unit power consumption (UPC) between the two systems (AWHS based on underground coils and vapor compression cycle (VCC) cooling sources) indicates that the underground coils have a UPC that is approximately 10% to 15% lower than that of the VCC systems.