What if you could get fresh water while also generating clean and renewable electricity? Sounds like a really ideal case but these researchers from Saudi Arabia and China have a solution. The new device they have developed can be used for both generating electricity and desalinating seawater and it’s highly efficient in doing both of them.
The device has been developed by Wenbin Wang and his colleagues at the King Abdullah University of Science and Technology in Saudi Arabia. Climate change is pushing many scientists and researchers to develop new and improved ways of generating electricity and reducing wasteful bi-products as much as they can. This new device is called a PV-membrane distillation-evaporative crystallizer or PME.
The PME combines desalination with electricity generation. It consists of a solar panel on top of a multistage membrane distillation or MSMD component. This distillation component is used to drive the water evaporation process and subsequently used to collect and reuse the waste heat from vapor condensation in each distillation stage to drive evaporation in the next stage.
According to Wang, “The high desalination performance of this design is attributed to the recycling of the latent heat of vapor condensation”. The MSMD component works in five stages in tandem with its four parts: a thermal conduction layer, an evaporation layer, a hydrophobic membrane, and a condensation layer.
The component itself is fixed on top of an evaporative crystallizer. The crystallizer uses the latent heat from the last distillation phase to evaporate off the liquid from the final concentrated brine that is produced alongside the freshwater, leaving behind only solid salt. Thus no waste is produced in the process.
According to Wang, “The key development with this device is the utilization of the hydrophobic membrane with a low thickness and high porosity, which is guided by our theoretical model. Previous work mainly utilized the hydrophobic membrane with a high thickness to reduce the thermal conduction loss and our theoretical model found that reducing the thickness of the hydrophobic membrane can achieve a high desalination performance and low solar cell temperature simultaneously”.
The team members are currently hard at work on scaling the device up for commercial use. They plan to build a photovoltaic farm that combines electricity generation and seawater desalination.