Desalinate sea water with energy from the sun? This innovation from MIT will make headlines!

Camille Coirault

October 18, 2023 at 7:00 p.m.


Ocean © The oceans, future oases in the quest for drinking water?  © Matt Hardy / Unsplash

The oceans, future oases in the quest for drinking water? © Matt Hardy / Unsplash

The Sun is an inexhaustible source of energy, at least on a human scale. Thanks to a discovery from MIT, its radiation could be used to desalinate seawater.

Drinking water is disappearing and shortages will become more and more regular. Some countries are already going through serious crises and are experiencing climate change head-on. The Asian Development Bank estimates that 2 million people die a year from lack of clean water in India alone. According to a recent UNESCO report, it will only take six years for the country to have a 50% water deficit. And this is just one example among many.

The urgency is critical, and the race for drinking water is a priority today. MIT, after recently being noted for the creation of a revolutionary implant for diabetics, once again shows the extent of the skills of its researchers.

A solar device with astonishing performance

This rather brilliant system was designed through close collaboration between engineers from China and the Cambridge Institute of Science. This innovation is based on a rather simple and intuitive principle to understand: the capture of sea water and its heating thanks to the Sun. It is a passive solar device that mimics the thermohaline circulation of the ocean (ocean circulation based on differences in seawater density). The prototype is currently called TSMD, to Thermohaline convection enhanced Solar Membrane Distillation.

By imitating this natural phenomenon, it allows the evaporation of water, which then transforms into water vapor. Once this vapor is condensed, it therefore provides consumable fresh water. The first tests carried out on a small scale are rather conclusive, since the system is capable of supplying between 4 and 6 liters of water per hour. Another big advantage also: maintenance reduced to almost zero, because the machine could operate for years without requiring part replacement. It has in fact been tested in extreme conditions: 180 hours of continuous desalination with seawater loaded with 20% salt, which is equivalent to 229 days of operation with conventional seawater (3.5% salt). ). No major deterioration was reported and fresh water production remained stable.

MIT desalination © The solar desalination system in question © Jintong Gao and Zhenyuan Xu

The solar desalination system in question © Jintong Gao and Zhenyuan Xu

Hope for coastal communities

This technology, if it develops correctly, could be truly life-saving for coastal areas where populations sometimes live completely isolated from drinking water networks. Communities which therefore live with an almost unlimited quantity of salt water at hand. Such a device could offer them access to water resources at an extremely low cost. Lenan Zhang, a researcher at MIT, explains: “ For the first time, water produced by sunlight may be even cheaper than tap water “.

While classic desalination is a process normally requiring very high energy consumption and very expensive implementation, this MIT prototype could change everything. The tests must continue, but if they prove to be as positive as ever, TSMD could be a real revolution.

Sources: Enerzin, cell, UNESCO

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