Thermal analysis of humidification–dehumidification desalination system based on evacuated tube solar air heater

Desalination, which converts saline water into freshwater, has been proposed as a possible alternative to address the worldwide freshwater scarcity problem. The humidification–dehumidification (H–DH) desalination technique can provide appropriate quantity of freshwater to the population residing in water-stressed regions. The aim of the current study is to investigate the solar H–DH desalination system performance which consists of a solar air heater based on double-ends open evacuated tube collector, a packed bed humidifier, and a dehumidifier. The packing material used in humidifier is aspen pads. The performance is assessed based on system overall efficacy, gained output ratio (GOR), yield, and efficacy of humidifier and dehumidifier at three distinct process air flow rates. The average overall system efficacy, yield, and GOR are 11.97%, 4.1 kg day^-1, and 0.84, respectively, for open-loop system. The closed-loop system reports better performance at low mass flow rate. The average overall system efficiency, daily yield, and GOR at 100 kg h⁻¹ are 32.48%, 11.9 kg day^-1, and 2.44, respectively, for a closed-loop system.