Thermodynamics analysis of a lab scale humidification-dehumidification desalination system employing solar energy and fogging approach

Abstract

Providing essential fresh water for drinking purposes is a crucial task. Most regions worldwide have the brackish or salty bulk water, which is not suitable for drinking. An experimental water desalination system based on the humidification-dehumidification (HDH) technique is provided in this study. Solar energy was used to power the proposed HDH desalination system by employing a photovoltaic solar panel to generate electricity, and an evacuated tube solar collector (ETSC) to heat the feeding water and air. Moreover, the HDH desalination system employed the novel technology of three fogging nozzles, 10 µm each, which showed promising results regarding exergy efficiency and freshwater productivity. A productivity rate of 1.70 kg/hr freshwater was recorded when the mass flow rate ratio of seawater to dry air was 0.857, and it was possible to reach 3.80 kg/hr when the inlet feedwater was heated to 80 °C. The gain-output ratio was achieved at the value of 3.41 for the same mass flow rate ratio of 0.857 and feedwater temperature of 80 °C. The minimum amount of total specific entropy generation (0.256 kJ/ (kg. K)) was obtained at a mass flow rate ratio of 0.857 and feedwater temperature of 60 °C.