Energy, exergy, economic, and environmental (4-E) analysis of atmospheric water harvesting system based on desiccant wheel using solar air heater

Solar powered atmospheric water harvesting (SPAWH) is an innovative and sustainable approach that addresses the urgent need of a drinkable water source. Low productivity and the use of high-grade energy limits the application of existing systems. In the present work, the performance of the SPAWH system has been evaluated based on 4-E analysis. Prior to experimental investigation, a numerical model of the desiccant wheel has been developed and favourable operating parameters for atmospheric water harvesting have been obtained. The recommended rotational speed of desiccant wheel, regeneration air velocity, facial area ratio and regeneration air temperature as per available ambient conditions are 15 RPH, 2 m/s, 3 and 150 °C respectively. Then, the desiccant wheel is connected to the double ends open evacuated tube solar air heater and air-to-air heat exchanger for atmospheric water harvesting under ambient condition. The system generates 10.5 L of water throughout the day with an average energy and exergy efficiency of 9.83 % and 2.56 % respectively. The cost of obtained water is estimated to be 0.24 $/L with a system payback period of 5.3 years. Considering the environmental aspect, this system mitigates 13.64 tons of CO2 in the lifespan with earned carbon credit of $197.8. [Display omitted] •A novel atmospheric water harvesting system based on a desiccant wheel is proposed.•The mathematical model of desiccant wheel has been developed.•The double ended open ET-SAH is used to regenerate the desiccant wheel.•This system is able to produce 10.5 L of water in a day.•The system mitigates 13.64 tons of CO2 in the lifespan with carbon credit of $198.