Windmill for Seawater Desalination Tested

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The Delft University of Technology (TU Delft) in The Netherlands has developed a reverse osmosis membrane that produces fresh water from seawater directly. This method uses a high-pressure pump to push the water through a membrane and it uses a traditional windmill to drive the pump: that is the simple concept behind the combination of windmill/reverse osmosis.

The University press release says that the windmill is suited for use by, for instance, small villages in isolated, dry coastal areas.

The combination of windmills and desalination installations is already commercially available. These windmills produce electricity from wind power; the electricity is stored and subsequently used to drive the high-pressure pump for the reverse osmosis installation.

This is an expensive process and the storage of electricity in particular is very expensive. Also energy is lost during the conversion. Energy is also lost during conversion.

In the TU Delft installation, the high-pressure pump is driven directly by wind power. Water storage can be used to overcome calm periods. The storage of water is much cheaper than that of electricity.

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The windmill is normally used for irrigation purposes. These windmills turn relatively slowly and are also very sturdy. On the basis of the windmill’s capacity at varying wind speeds, it is estimated that it will produce 5 to 10 m3 of fresh water per day.

This is enough drinking water for a small village of 500 inhabitants.
It is necessary to have a water reservoir to ensure that enough water is available for a calm period lasting up to five days.

Three safeguards (in the event of the installation running dry, a low number of revolutions or a high number of revolutions) are also performed mechanically so that no electricity is needed.

The first prototype has been built and is already working at a location near the A13 motorway near Delft. This prototype is to be dismantled and transported to Curaçao the first week of March and then the concept will be tested on seawater.