If global warming has achieved one thing, it is that more and more people are aware of their energy usage and many of us frown upon the blatant waste of energy by others. That is why switching from the common light bulb to CFL’s has seemed like the proper thing to do. So why is it that millions of car owners all over the world still waste more than half of a car’s energy as heat? It is in fact considered to be one of the leading problems in energy use around the world.

That is why engineers at Oregon State University (OSU) in the USA have developed a device that turns the waste heat from car exhaust pipes, diesel generators, factories and electrical utilities into cooling or electricity.

Now, more than half of the heat generated by industrial activities is wasted and cars are even worse, wasting up to 75 percent of their energy as heat. Engineers have come up with various approaches to capture and use at least some of the waste heat to produce cooling. What makes the new system developed at OSU different is that it will do so more efficiently, while being more portable. But the major advantage is that besides cooling it can produce electricity as well.

The device 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 existing energy conversion technology called an ‘organic Rankine cycle’.

The prototype succeeded in turning 80 percent of the waste heat into cooling capability. When producing electricity the system would not be as efficient, reaching only 15 to 20 percent efficiency, but it is still better than the current approach of wasting all the potential energy.

The technology is exceptionally suited in places where a cooling system is needed while heat is being wasted. But it could also be incorporated into alternative energy technologies such as solar or geothermal. In automotive technologies it would seamlessly fit in the setup of hybrid cars, taking waste heat from the gasoline engine and using it not only for air conditioning but also to help recharge the battery that powers the vehicle.

© Jorn van Dooren | www.bitsofscience.org

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