Parametric study of a tandem desalination system based on humidification-dehumidification process with 3-stage heat recovery

A heat recovery with tandem desalination system based on humidification and dehumidification process was investigated experimentally in this paper. The sketch and principle of a 3-stage multi-effect solar HDH desalination process are given out. These are the one-dimensional heat and mass transfer control models of humidifier and condenser. The mathematical model of the system is developed and governing conservation equations are numerically solved by using the Engineering Equation Solver (EES). In this experiment, different effects of heating ways on the high and middle stages of the desalination unit were studied, including spraying temperature, air flow rate, condenser drainage and the supplement water mass flow rates. The maximum yield of the unit can reach 0.182 m3/h, the maximum GOR of the system can reach about 2.65. The results indicate that the yield of the system decreases with the increase of the supplement water flow rate and condenser drainage. In order to ensure the stability and reliability of the system, the optimal yield can be realized only when isothermal heating is adopted in higher and middle stages. The system obtains fresh water by multi-stage isothermal heating mode and the cost is about $2.5 per ton.