Technology Transfer: Innovative way to get water and power simultaneously
Here is an interesting idea that would synthesize renewable energy and desalination. “Now, researchers at the Delft University of Technology have come up with an interesting idea — combining windmills with reverse osmosis filters to produce comparatively rugged and low-cost desalination systems” (WorldChanging).
Desalination is an energy intensive process and Reverse Osmosis (RO) desalination is by far the most energy efficient technology to desalinate water. Reverse Osmosis is a pressure difference separation technique. It uses the natural osmosis process that occurs through a semi-permable membrane with two solutions that have different concentrations of salts in it. At equal pressure and temperature the water will flow through the membrane from less concentrated solution to one with larger concentration, and will delute it, till the concentrations are equal. When a certain pressure applied that is larger then a certain osmotic pressure the flow goes the other way, flowing from a more concentrated side to a more deluted solutions. That process is called Reverse Osmosis.
There are a few experimental RO installations throughout the world that are driven by electricity produced by wind turbines. In these systems the wind energy first transformed to electricity, then stored, and transferred to mechanical energy back to drive the high pressure pumps that pressurize the feed water for the RO-installations. Throughout these transformations energy losses occur. To minimize the energy losses a direct connection between the windmill and the high pressure pump is developed. The RO installation is operated intermittently due to the variable character of the wind and product water is stored, which is much less expensive then the electricity storage facilities. The desalination installation is operated fully mechanically and hydraulically.