Vapour collection technology allows steam from power plant cooling towers to be recovered, saving large amounts of water
Spotted: A perhaps little-remarked upon fact is that power plants use huge amounts of water. As much as two-fifths of all the water withdrawn from lakes, rivers, and wells in the US is used to cool power plants. Many of these plants use evaporative cooling – which is the source of those huge white plumes that can be seen billowing from their cooling towers. Now, a company based on technology developed at MIT has come up with a way to recover most of that water.
The company, Infinite Cooling, is led by Maher Damak and Karim Khalil, who both worked on the concept for their PhDs and MIT professor of mechanical engineering Kripa Varanasi. The technology was originally meant to improve the efficiency of fog-harvesting systems, which are used in some arid coastal regions as a source of potable water. Those systems use plastic or metal mesh hung in the path of fogbanks, but they are very inefficient, only capturing only around 1 to 3 per cent of the water droplets that pass through them.
The researchers improved the efficiency of the reclamation process by first zapping the steam or fog with a beam of electrically charged ions, giving each water droplet a slight electric charge. The wire mesh is then given the opposite charge. As the charged droplets pass through the mesh, they are strongly attracted to it and are collected in trays placed underneath.
The system has been tested on the cooling towers of MIT’s Nuclear Reactor Laboratory research facility, demonstrating its effectiveness in a reactor licensed by the Nuclear Regulatory Commission. The team felt this was an important step in “de-risking” the technology for commercial use. The system was able to collect water that was “more than 100 times cleaner than the water coming into the cooling system,” and had no effect on the plant’s operation.
As the planet heats up, water shortages are going to become a persistent threat in more areas. This system is just one of the ways that innovators are seeking to mitigate this problem. Others that we have seen at Springwise include a “Fitbit” for your water metre and a synthetic tree that acts as a water purifier.
Written By: Lisa Magloff