New Harvester Transforms Wasted Heat into Useful Energy
CREDIT: Hailei Wang/Oregon State University
With gas and electricity prices turning wallets into sieves, it's a painful time to think about how much wasted energy seeps out of our cars and electronics in the form of heat. But anyone who has baked his legs under a laptop can testify that the problem is real.
Dr. Hailei Wang, a mechanical engineer at Oregon State University, has designed a prototype machine that can recover heat from industrial components and use it to either power a cooling system or generate electricity . His device improves on established heat conversion systems such as the recently developed ElectraTherm.
It's particularly difficult to utilize heat from most industrial machines because heat comes out at a temperature below the boiling point of water.
"Because it's low-grade, there's no easy or economical way to recover it," Wang told InnovationNewsDaily.
Both the ElectraTherm and Wang's prototype confront this challenge using a technology called the Organic Rankine Cycle, also known as ORC. Fluid in the system boils at low temperatures. As heat transfers to the fluid, it can be used to drive an expander, which then generates power. Wang improved the system by running the fluids through extremely narrow channels, only a few hundred microns wide, to more effectively transfer the heat to the fluid.
Wang's heat harvester would be most efficient when used to power a cooling cycle, returning up to 80 percent of the wasted energy. A portable version of his prototype could conceivably replace or supplement radiators in cars and other big heat producers, making the entire system more efficient.
The device can also return wasted energy to a power generator. While doing so would have much lower efficiency, it would still be enough to take some of the heat off our energy demands.