One of the leading problems in energy use around the world today? Emissions that contribute to climate change? Nope. The waste of half or more of the energy produced by cars, factories and power plants, according to engineers at Oregon State University.

This may be something that just gets blown off in the energy debate (as in through a tailpipe).

OSU has completed a successful prototype that captures and uses the low-to-medium grade waste heat that’s lost out of the exhaust pipe of cars and trucks, or out the stacks of factories and electrical utilities, according to university officials.

If it’s good enough for landfills, as in creating electricity from the methane that’s usually burned off, then why not waste heat? The Oregon researchers say the potential of recycling vehicle exhaust is enormous, and new systems being developed at the university should be able to reuse much of that waste heat for cooling or producing electricity.

Photo Courtesy OSU

Hailei Wang, a research associate at OSU, says the new prototype is more efficient than previous methods used for capturing and using waste heat. The system also has the added advantage of being able to produce electricity.

How does it work? The details have been published in a professional journal called Applied Thermal Engineering.

The technology, called a “thermally activated cooling system,” gains much of its efficiency by using mini microchannels (no wonder OSU has a Microproducts Breakthrough Institute). The system effectively combines a vapor compression cycle with an existing energy conversion technology called an “organic Rankine cycle,” researchers say.

The result is a machine that turns 80% of every kilowatt of waste heat into a kilowatt of cooling capability. The conversion efficiency for producing electricity is only 15-20%. Not bad.

This looks like a way to put waste heat to work, rather than just releasing it back to the atmosphere. How much additional energy can this technology save? Enough to put more hybrid-electric vehicles on the roads, and cut power usage by factories and power plants, hopefully.

Researchers at Northwestern University also are working on ways to harness waste heat.