Performance of a Two-Stage Multi-Effect Solar Desalination System Based on Humidification-Dehumidification Process

A novel two-stage multi-effect solar desalination was presented based on humidification-dehumidification (HDD) process. Experimental study on the performance of device was carried out with an electric heater to simulate solar collector. The main objective of this work was to investigate the thermal efficiency and the water productivity of the unit. In the experiment, the effects of operating parameters on the performance of the desalination unit were studied, including heating temperature, brackish water flow rate and the supplement mass of brackish water. The temperature variation and the yield under different operating temperature were obtained. The effect of the brackish water flow rate on the yield of the unit was analyzed theoretically and compared with the experimental research results. So the gained output ratio (GOR) of the device can be obtained for different operating conditions. The research results show that the yield of the device increases with the increase of the water flow rate and the heating temperature; the yield of the unit can reach 63.55 kg/h at the water flow rate of 1 000 kg/h. The GOR of the multi-effect solar desalination system can reach about 1.98, as the heating temperature is 85 ℃, because it recycles and reutilizes latent heat in the humid air and the residual heat in the brine. The trend of the GOR calculated theoretically is the same as that obtained in experimental results. This multi-effect solar humidification-dehumidification desalination system could be potentially improved through optimization of its design and operation.