The action of cooling things down plays a critical part of any mechanical or electric system, because the inevitable heat, produced by friction, is the number one cause of almost instant failure. So far, different methods that cool systems have been discovered, but not to the extent of performance that engineers dream of building their computers or mechanical devices (cars, for example).
Oregon State University researchers, led by Terry Hendricks, have discovered a method of applying a nanostructured coating that could make the heat transfer more easily. Their findings have been published in the International Journel of Heat and Mass Transfer, and they also filed a patent for them.
The coating, made of zinc oxide with an aluminum and copper substrate is very cheap to make industrially, even cheaper than carbon nanotubes, which need high temperatures to be manufactured. Despite those, the zinc oxide nanocoating needs low temperatures.
“Many electronic devices need to remove a lot of heat quickly, and that’s always been difficult to do,” said Chih-hung Chang, an associate professor in the School of Chemical, Biological and Environmental Engineering at Oregon State University. “This combination of a nanostructure on top of a microstructure has the potential for heat transfer that’s much more efficient than anything we’ve had before.”
Hendricks says: “For the configurations we investigated, this approach achieves heat transfer approaching theoretical maximums [...] This is quite significant.” The applications range from microelectronics to industrial scaled ones. The heat transfer coefficient resulted by using the new coating is 10 times higher than that of uncoated surfaces.
For water to reach its boiling point of 100 degrees Celsius, the temperature of the adjacent material has to be about 140 degrees, for example. With the same material having the surfaces painted with their new coating, the temperature needed is only of 120 degrees.
So, cooling is not only vital for any system to work, but can also increase the efficiency by dissipating the heat. Cars can get more powerful, computer can get a lot faster, and solar cells, for example, can render high efficiencies much easier. Heat, being one of the components of sunlight, can be extracted a lot easier if the materials used to carry the exchange liquid are treated with this coating. And they can be a lot cheaper, too.
See the example of Dow Chemicals, who made solar shingles that harvest all the parts of sunlight. They have a photovoltaic cell layer, a thermoelectric layer and the rest of the heat goes into pipes filled with an exchange liquid, carrying the heat energy and have it used in your home.