Turning Waste Heat Into Power | .....Aaron's EnvironMental Corner.....

Turning Waste Heat Into Power Posted on June 21st, 2009

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General Electric and Idaho Labs are working together to create cheap electricity from the waste heat of industrial engines. They announced that they’d received $2 million in Department of Energy grants to further develop this technology earlier this month.

So long as there’s industry, there will be machinery and the engines to power it. Most engines of this kind, according to GE, are only about 35% efficient with the remaining 65% of the energy potential from their fuels being wasted as heat and unused byproducts. The GE-Idaho Labs joint plan is to capture some of this wasted energy and use it.

For over a hundred years, a process called the Organic Rankine Cycle has been around, but seldom used, because it’s generally expensive to utilize in practice. The process traditionally uses a fluid to capture waste heat from an engine and transfer it to another medium for conversion to electricity or another energy source.

In some factories, for instance, the ORC can be used productively to take waste heat from engines and pre-heat water, reducing the amount of energy required to heat the water.

In GE’s new process, however, an improved ORC process uses an evaporator rather than fluid to transfer the waste heat–hopefully being more efficient and losing less of the heat in the process. The idea behind this design is to transfer and utilize much lower heat sources and convert it to electricity. So a wider range of power sources (coal plant equipment, small gas turbines, even the air transfer units at mines and in large factories/warehouses) can be utilized.

There’s tons of potential from these types of machines. Similar concepts are being used in a variety of ways, including steam stacks being utilized to turn turbines for electrical production and even thermoelectrics, which convert heat directly into power (albeit expensively, for now).

The goal, of course, is to ultimately have energy potential to energy use being as clsoe to 100% as possible.

Here’s more on the GE-Idaho Labs research.