A hybrid solar desalination system of air humidification–dehumidification and water flashing evaporation: Part I. A numerical investigation

• The current study makes a focus on a hybrid solar desalination system
• The system consists of humidification–dehumidification unit and single stage flashing evaporation unit.
• The proposed system gives considerable daily water productivity up to 94.6 kg.

This paper presents a hybrid solar desalination system consisting of a humidification–dehumidification unit and single stage flashing evaporation unit. The hybrid solar desalination system was studied numerically. The heat and mass transfer and flow field are modeled theoretically in two dimensions using the finite difference scheme. For different operating and weather conditions, the fresh water productivity and salinity are computed. The model is developed to investigate the steady-state behavior of each component of the system. Six main parameters that have influence on the system productivity are studied; feed water mass flow rate of SSF unit, feed water mass flow rate of HDH unit, cooling water mass flow rate of SSF unit, cooling water mass flow rate of HDH unit, air mass flow rate and inlet cooling water temperature. The results show that, the studied hybrid desalination system gives a significant operational compatibility between the air humidification–dehumidification method and flash evaporation desalination with daily water production up to 11.14 kg/m2/day. The efficiency of the system is measured by the gained output ratio (GOR) with day time. The gained output ratio (GOR) of the system reaches 4.5. The effect of the water and the air solar heaters collecting areas on the system productivity is measured. The trend of air solar heater collecting area variation showed a pronounced increase in the fresh water productivity than that of the water solar heater collecting area variation.