Researchers Invent Efficient But Inexpensive Solar Desalination Device that Offers Drinking Water

Researchers from the Massachusetts Institute of Technology in the USA and Shanghai Jiao Tong University in China have invented a passive solar evaporation system that can clean saline water and waste water which could further help the communities to have access to drinkable water.

The best part is that the novel device is inexpensive and decentralised in nature that can be installed anywhere and work in most conditions.

According to the study published in the journal ‘Nature Communications,’ the team of researchers was MIT’s Lenan Zhang, Xiangyu Li and four others.

As far as the technology is concerned, a wick-free system was created to eliminate salt accumulation. The device had a dark material at the top to absorb the sun’s heat and warm the device. Then comes a thin layer of water, followed by a perforated layer of material. This system is fitted above the saline water, waste water or pond containing non-potable water.

The inventors used wicking structures and novel materials to achieve high performance. To eliminate the accumulation of salt in the system and ensure that the device is not rendered inefficient, the researchers employed natural convention to avoid using materials that accumulate salt.

They drilled 2.5 mm holes that were the best suited holes through the perforated material employing a high-pressure waterjet. There can be other methods to create them.

As far as the process is concerned, in the evaporation process, the water that sits above the layer saltier and the small drilled holes allow the exchange of salt between the water on top and the reservoir that’s beneath. Researchers say that this is possible due to the difference in density between the water with salt on top and the water below.

Other designs have reliability issues. The MIT researchers have used natural convention that is simply based on the geometrical manifestations. As per the researchers, the cost comes around just $4 per square meter of device and it’s made from household materials.

Until now, the device has just achieved a great level of desalination and evaporation. The system needs further improvements. There will need a condenser that will collect the water and render the invention meaningful. MIT is hopeful that this addition will also remain cost effective and will be developed soon. The researchers opine that one square metre device can desalinate or clean about 6.5 litres of water.