A novel solar-driven water and electricity cogeneration integrated system by multistage vaporization enthalpy recycling

Abstract

Satisfied the long-term demand for electricity and freshwater shortage in off grid and resource constrained areas through clean energy is particularly important in the context of comprehensive clean and green development. In this paper, a novel solar-driven freshwater-electricity cogeneration system was proposed, which has high efficiency solar-thermal-electrical conversion capability and outstanding thermal management performance. First, a solar-thermal-electrical coupling numerical model of the system was established, the energy transmission and transformation mechanism were analyzed, and the structural parameters such as the air gap and distillation stages were optimized to further improve the performance of the system. Second, guided by theoretical modeling, the outdoor experiment verified the outstanding thermal management performance through evaporative cooling of seawater and the efficient solar-electricity-steam conversion ability of the system. A photovoltaic module temperature was reduced to about 8 °C, as compared to the same photovoltaic module working alone. And the reduced photovoltaic module temperature led to a 0.86 % increase in average solar-electricity conversion efficiency. Meanwhile, a large amount of freshwater was obtained by consuming the waste heat of photovoltaic modules. The average water production rate was about 2.06 kg·m−2·h−1 under the real outdoor environment. Finally, the system has a stable self-cleaning ability without solid salt crystallization and efficient seawater desalination performance in freshwater production. Hence, this novel system not only realizes passive high energy transfer efficiency to produce freshwater and electricity, but also provides a strategy to solve the crisis of energy and water resources in the future.