A compact design of water heating–humidification processes for solar hdd systems

Abstract

This work investigates the thermal performance of a solar humidification technique that is suitable to use in a Humidification Dehumidification Desalination system (HDD). Water heating and air humidification processes have been merged to take place in a direct contact water solar thermal collection unit. Experiments are conducted under the weather conditions of N. Cyprus. Air passes through brackish water in the humidifier and reaches saturation at the outlet. The difference between temperatures and relative humidity at the inlet and outlet of the humidifier were recorded for different airflow rates (8.2, 10.4, and 12.6 kg/h) between December 1 and 4, 2012. The experiment demonstrated that for an average solar radiation of 600 W/m2 and a mass flow rate of 12.6 kg/h of air, the increase in average absolute humidity was 0.62 kg/h m2. As the airflow rate was stepped up, the rate of vapor transfer increased but the efficiency of the humidification process slightly dropped. © Springer International Publishing Switzerland 2014.