Experimental investigation of a multi-effect isothermal heat with tandem solar desalination system based on humidification-dehumidification processes

A new multi-effect solar desalination system based on humidification-and dehumidification (HDH) process was investigated experimentally in this paper. Several hourly yields with operation temperatures were tested and analyzed. The warm saline water is sprayed upon the porous ball humidifiers, which is simple and effective for enhancing the evaporation process. A mathematical model based on the mass and energy balances in each unit of the system is developed which is used to optimize the test. In addition the performance ratio (PR) of the device was investigated under different feeding water mass flow rates and heating temperature conditions. The experimental results indicate that the yield of system increases with the increase in water flow rate and air flow rate. The maximum PR of the system at the heating temperature of 85°C can reach up to about 2.65. When the heating temperature increases from 60 to 90°C and the feed water flow rate is 2t/h, the fresh water yield increases from 59.41 to 182.47kg/h. The yield per unit volume is calculated as 22kg/m³h. The numerical results based on the mathematical model are well in agreement with the experimental results. The maximum relative deviation is only 5%.