This prototype of a “thermal activated cooling system” has been developed by engineers at Oregon State University, and promises important new advances in energy efficiency by using wasted heat. (Photo courtesy of Oregon State University)
A “thermally activated cooling system” that gains much of its efficiency by using extraordinarily small microchannels which help to better meet the performance, size and weight challenges. It effectively combines a vapor compression cycle with an “organic Rankine cycle,” an existing energy conversion technology.
The new prototype completed at OSU succeeded in turning 80 percent of every kilowatt of waste heat into a kilowatt of cooling capability. Researchers say the conversion efficiency wouldn’t be nearly as high if the goal is to produce electricity – about 15-20 percent – but it’s still much better than the current approach, which is to waste the energy potential of all of the heat.
More than half of the heat generated by industrial activities is now wasted, Wang said, and even very advanced electrical power plants only convert about 40 percent of the energy produced into electricity. The internal combustion engines of automobiles are even worse – they generally operate around 25-40 percent conversion efficiency. The very function of an automobile radiator is to dissipate wasted heat.
“This technology would be especially useful if there’s a need to have cooling systems where heat is being wasted,” Wang said. “That’s one reason the research has been supported by the Department of Defense, because they see it being used to provide needed air conditioning for electronics and other purposes when they are using generators in the field.”
However, the OSU scientists said that may be just the beginning. Factories often produce enormous amounts of wasted heat in their operations. The systems could also be incorporated into alternative energy technologies such as solar or geothermal, scientists say, in addition to fossil fuel use.