Development of a photovoltaic-thermal solar humidifier for the humidification-dehumidification desalination system coupled with heat pump

To provide both thermal and electrical energies needed for the humidification-dehumidification (HDH) desalination systems independent of fossil fuels, the present study proposed a photovoltaic-thermal (PVT) solar humidifier. The designed humidifier is a double-pass dual-fluid solar collector, which was mounted on a humidification-dehumidification system equipped with a heat pump. Experimental investigation of the system was conducted at different condensation temperatures and seawater flow rates. The results showed that the highest water evaporation in the humidifier was around 4.48 kg (1.06 kg/h/m(2) humidifier surface) at the seawater flow rate of 0.15 kg/s and the condensation temperature of 20 degrees C. Specific electrical energy consumption values varied from 0.22 to 0.53 kWh/kg. The maximum thermal and electrical efficiencies of the PVT humidifier were 75.6 and 11.3%, respectively. The ratio of solar PV electricity to consumed electricity of the system at the different operating conditions was ranged from 0.95 to 1.03. The average freshwater production rates were between 0.56 and 0.99 kg/h/m(2) humidifier surface. Economic analysis of the system indicated that the cost of freshwater production with the proposed system is 0.018 US $/kg.