Integrated solar-driven PV cooling and seawater desalination with zero liquid discharge

Summary

Utilizing the "waste heat" of solar cells for desalination enables the simultaneous production of freshwater and electricity and represents low barrier-of-entry electricity and freshwater supplies to off-grid communities for point of consumption. Herein, guided by theoretical modeling, this project demonstrated that a higher freshwater production rate and a lower solar cell temperature could be achieved simultaneously. With a five-stage photovoltaics-membrane distillation-evaporative crystallizer (PME), we experimentally demonstrated a high and stable freshwater production rate of ∼2.45 kg m⁻² h⁻¹ and a reduced solar cell temperature of ∼47°C under 1 sun irradiation, as compared to ∼62°C of the same solar cell working alone. The reduced solar cell temperature led to an 8% increase in its electricity production. Moreover, the concentrated brine produced in the process was fully evaporated by the underlying evaporative crystallizer, achieving zero liquid discharge. We expect that our work will have important implications for the understanding and advancement of solar distillation.