The first entry on my new blog:
The Stranded Sailor
According to a report
at the Massachussets Institute of Technlogy, scientists at MIT and Korea
have come up with a new way to desalinate water
[S]mall, portable units that could be powered by solar cells or batteries and could deliver enough fresh water to supply the needs of a family or small village. As an added bonus, the system would also remove many contaminants, viruses and bacteria at the same time.
While the report envisions the technology to be primarily used for disaster relief, I think its potential application to boaters is self-evident. Communities that live on small islands and rely on collecting rainwater should also benefit from this new technology.
Traditional watermakers rely on a process called “reverse osmosis” which requires high-pressure pumps to force salty water through special filter membranes that separate the salt
molecules from the water.
According to this report, the new approach to desalination is called “concentration polarization” and solves the biggest problems of watermakers: the need for high pressure pumps (and electricity/fuel to power them) and the fouling of osmosis
The system works at a microscopic scale, using fabrication methods developed for microfluidics devices — similar to the manufacture of microchips, but using materials such as silicone (synthetic rubber). Each individual device would only process minute amounts of water, but a large number of them — the researchers envision an array with 1,600 units fabricated on an 8-inch-diameter wafer — could produce about 15 liters of water per hour, enough to provide drinking water for several people. The whole unit could be self-contained and driven by gravity — salt water would be poured in at the top, and fresh water and concentrated brine collected from two outlets at the bottom.
And here’s the sweetest part:
If properly engineered, the proposed system would only use about as much power as a conventional lightbulb.
Yay! But don’t go tearing out your watermaker
just yet — the first commercial
systems are not expected to be available for a couple years.