Rotating Water Desalination Device Is Up to 400% More Efficient

The new machine uses a hollow rotating cylinder to speed up the evaporation process.
Chris Young
The water desalination deviceUrFU

An international team of researchers including engineers from Ural Federal University (UrFU) developed a new desalination technology with high-efficiency thanks to a rotating cylinder, a press release reveals.    

The technology takes advantage of solar energy for the distillation of water, potentially allowing dirty water to be made clean for large parts of the world suffering from water shortages — the UN, for example, states that more than 700 million people worldwide have no access to clean drinking water.

The team says that their method could significantly reduce the cost of desalination and multiply production volumes by four, they explained in a paper in Case Studies in Thermal Engineering.  

Their method utilizes a cylinder that is slowly rotated by a solar-powered DC motor. The rotating hollow cylinder is housed inside a rectangular basin that acts as a solar distiller. This cylinder accelerates water evaporation in the vessel by forming a thin film of water on its outer and inner surface. The film of water is constantly renewed with each turn of the cylinder, while the water below the cylinder is heated using a solar collector.

400% performance improvement over traditional devices 

The team tested a prototype on a rooftop in the Russian city of Ekaterinburg for several months in 2019. They found that at 0.5 rpm, the machine would allow the evaporation of a thin film of water from the surface of the cylinder.  

"The performance improvement factor of the created solar distiller, compared to traditional devices, was at least 280% in the relatively hot months (June, July, and August) and at least 300% and 400% in the cooler months (September and October), at the same time, the cumulative water distillation capacity reached 12.5 l/m2 per day in summer and 3.5 l/m2 per day in winter," said Alharbawi Naseer Tawfik Alwan, a research engineer at UrFU.  

Such a technology could be in great demand in areas like the Middle East in the coming years, as the region has a high solar energy capacity but faces water shortages. The city of Dubai, in the UAE, for example, is using electric shocks from drones to encourage clouds to rain over the region, which sees only 4 inches (10 centimeters) of rain annually. 

Another desalination device designed by Henry Glogau recently won the Lexus Design Award this year. His device doubles up as a no-cost skylight and is able to make seawater drinkable for poor areas that have low access to clean drinking water.

The UrFU researchers next hope to increase the performance of their solar distiller, reducing the operating costs wherever possible so as to allow their machine to help in regions that are desperately in need of clean drinking water.

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