Simulation of Hdh Desalination System Using Tilted, Two-pass Solar Air Heater

The present work represents a theoretical investigation of the performance of a solar air-heated desalination system using humidification-dehumidification (HDH) technique based on closed-water, open-air cycle under the geographical conditions of Dhahran (26.5°N, 50.2°E), Saudi Arabia. The HDH desalination system is suitable for small-scale decentralized fresh water production. It essentially consists of a tilted, twopass solar air heater, a humidifier, a dehumidifier in addition to a storage tank. In this system, air alone is heated in the solar air heater. A simulation program is developed based on mass and energy balance. The governing equations are simultaneously solved using Engineering Equations Solver (EES) to investigate the effect of the main design and operating parameters on the productivity of the water desalination system. It is found that the tilted solar heater outperforms the horizontal one by about 7% whereas the humidifier performance has a significant effect on the system productivity. Using a selective surface an increase the desalted water productivity by 39% compared to the units that do not have a selective surface.