Nobody likes the winter ritual of defrosting windows on a cold morning. Thanks to an international team of researchers at the University of Illinois at Urbana-Champaign and Japan’s Kyushu University, however, such indignities may not hang around for too much longer. They have developed a new way of removing ice and frost from surfaces with impressive efficiency — requiring less than 1% of the energy and 0.01% of the time required for traditional defrosting methods. In addition to car windows, it could be used for other surfaces, such as defrosting airplanes.
“The work was motivated by the large energy efficiency losses of building energy systems and refrigeration systems due to the need to do intermittent defrosting,” UIUC researcher Nenad Miljkovic said in a statement. “The systems must be shut down, the working fluid is heated up, then it needs to be cooled down again. This eats up a lot of energy when you think of the yearly operational costs of running intermittent defrosting cycles.”
The system uses a pulse of high current. This creates a layer of water where the ice and surface meet. To make sure that the pulse hits its intended target, the researchers apply a thin coating of conductive film indium tin oxide (ITO). The rest then relies on gravity, which causes the ice to simply slide off. This could also be aided by air flow if necessary.
So far, the tech is still at the proof-of-concept stage. The scientists recently demonstrated how their approach works by using it to defrost a piece of glass cooled to temperatures as cold as minus 159.8 degrees Fahrenheit. These incredibly low air temperatures are colder than the coldest parts of Antarctica. Using their technology, the researchers were able to remove ice with one pulse lasting under one second.
These researchers are not the only ones working on a similar solution. At ETH Zurich in Switzerland, scientists have developed a solar-activated nanoscale-thick coating which captures sunlight and uses it to defrost windows rapidly. Meanwhile, at Virginia Tech, investigators have developed an innovative water-repellent aluminum surface which uses millions of tiny air pockets to significantly speed up thawing speeds. Hopefully it won’t be too much longer before one of these approaches finds its way to market.
The Urbana-Champaign and Kyushu University research was recently described in the journal Applied Physics Letters.