Development of Small-scale Two-stage Photovoltaic-photothermal Humidification-dehumidification Desalination System

Air bubble has been proved that it can increase evaporation area and coefficient of mass transfer and heat transfer. Two-stage evaporation system can indirectly increase the contact area of water and vapor, reduce the volume of single evaporation system, and can also combine the multiple systems flexibly. So a new type of small scale two-stage photovoltaic-photothermal humidification-dehumidification (HDH) desalination system is designed, and the relationship between solar radiation and temperature is measured, and the water production capability of the system is investigated. The effect of water temperature, ambient temperature, air flow rate and air temperature on desalination performance is also investigated. The results showed that the rate of water production is positively correlated with sea water temperature, ambient temperature, gas flow rate and air temperature. And the gas temperature is positively correlated with the solar radiation intensity. When the ambient temperature is higher than 25 ℃, the cumulative amount of irradiation is 22.3 MJ/m2, the cumulative water production is 19.2 L/d, and 6.4 L/( m2∙d), the thermal efficiency is 0.66. The cost of water produced through the designed HDH system is 0.08 $/L.