New Generator Prototype Converts Waste Heat Into Electricity

Researchers at the University of Texas, Dallas have developed a generator that converts waste heat into electricity.

Heat is an abundant renewable energy source. According to the researchers, data centers spend lots of time getting rid of heat using chillers and air conditioning.

Meanwhile, the focus should be on recycling the heat back to electricity. Other appliances such as air conditioners, including electric car batteries, are also a source of waste heat.

Past attempts to harvest energy from waste heat have only explored processes like manufacturing and steel mills that generate high-temperature heat byproducts. The UT Dallas researchers, on the other hand, focused on sources that generate lower-temperature heat – between 80 and 115 degrees.

Founding director of the Renewable Energy and Vehicular Technology Laboratory at UT Dallas, Babak Fahimi noted:

“Renewable sources of energy, such as electric cars, all have fantastic merits. One thing we don’t do anything about is how to recycle the heat they generate. If there is a way to recycle that heat back to electricity, that would be fantastic.”

So, the UT Dallas team created a way to do just that. It began with a magnetohydrodynamic power (MHD) generator.

Using Liquid Metal to Convert Waste Heat Into Clean Electricity

MHD generators generate electricity by moving fluids through a magnetic field.

While the technology has been around since the 1960s, it has never enjoyed wide adoption. Then, a UT Dallas doctoral student, Eva Cosoroaba, proposed an MHD generator that uses gallium for the working liquid.

Why gallium, you ask?

Gallium becomes a liquid at a temperature that’s greater than 85 degrees – perfect for harvesting low-temperature heat sources. Also, it conducts electricity better than most conductive fluids

“Dr. Cosoroaba demonstrated that we could harvest energy from low-temperature sources of heat and use that heat to melt and maintain the liquid metal that in turn drives the generator,” Fahimi said

The technology has several potential applications.

For example, it could improve the efficiency of electric vehicles by converting the heat from their batteries into electricity. Similarly, data centers can turn all the waste heat that the computers generate into energy.

The researchers detailed the project in the October print edition of Sustainable Energy Technologies and Assessments.