A series of advanced studies in microchannel technology at Oregon State University has led to the invention of a waste heat recovering device that can convert heat into cooling with an 80% efficiency.
Most factories and power plants around the world currently get rid of waste heat, and the most advanced of them transform heat into electricity, but their approaches are usually no more than 25 to 40 percent efficient.
“This could become a very important new energy source and way to improve energy efficiency,” said Hailei Wang, a research associate in the School of Mechanical, Industrial and Manufacturing Engineering at OSU. “The prototype shows that these systems work as well as we expected they would.”
The OSU invention is called a “thermally activated cooling system,” and owes its high efficiency to 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 heat recovery system developed at OSU is far more efficient than anything on the market today, and also has the advantage of being able to generate electricity. Of course, the efficiency in this case would be way lower, down to 15 percent, as the scientists involved in the project say.
So the project is perfectly fit for powering air conditioning units with heat, and could have important effects on those cars and power plants that use heat exchangers and radiators to get rid of extra heat. That includes solar and geothermal energy harvesting, where there’s a lot of energy dissipated in the form of 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.”