Is Heat a Resource?

By | June 5, 2007
4 Comments

…apparently so. Utah physicist Orest Symko has developed a way to turn waste heat into sound which is then converted into electricity.

“It is a new source of renewable energy from waste heat.”

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Using sound to convert heat into electricity has two key steps. Symko and colleagues developed various new heat engines (technically called “thermoacoustic prime movers”) to accomplish the first step: convert heat into sound.

Then they convert the sound into electricity using existing technology: “piezoelectric” devices that are squeezed in response to pressure, including sound waves, and change that pressure into electrical current. “Piezo” means pressure or squeezing.

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Devices that convert heat to sound and then to electricity lack moving parts, so such devices will require little maintenance and last a long time. They do not need to be built as precisely as, say, pistons in an engine, which loses efficiency as the pistons wear.

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The research is funded by the U.S. Army

speculist dune.JPGSymko thinks that these devices can be shrunk for use in laptop computers. They could reduce heat and extend battery life at the same time. Also he thinks they might be used as an alternative method for getting electricity from sunlight. You could put these devices in a small greenhouse box on your roof and plug in. No word yet on whether this could provide more electricity per dollar invested than photovoltaic cells.

If our country moves to hybrid vehicles, why not use our hot cars to charge those lithium ion batteries? Both engine heat and cabin heat could be used. We southerners could get some serious mileage out of cabin heat. Just sitting in the parking lot my truck typically gets over 120 degrees Fahrenheit in August.

The interim sound step is important. It serves to organize the energy in preparation for a conversion to electricity:

“You have heat, which is so disorderly and chaotic, and all of a sudden you have sound coming out at one frequency,” Symko says.

And they won’t drive us crazy with their noise:

Symko says the devices won’t create noise pollution. First, as smaller devices are developed, they will convert heat to ultrasonic frequencies people cannot hear. Second, sound volume goes down as it is converted to electricity. Finally, “it’s easy to contain the noise by putting a sound absorber around the device,” he says.

  • Phil Bowermaster

    This is a good idea for household appliances, too. Imagine if just refrigerators and air conditioners could put some measure of the juice they use back into the grid via converted heat.

    Also, I wonder if this technology could be distributed over rooftops and highways — both great solar heat collectors.

  • MikeD

    Is heat a resource? I believe many people would agree that it is, especially when attempts are made by their spouse to usurp that resource rather than put on socks. :)

  • Karl Hallowell

    Keep in mind that some people and many animals can hear ultrasonic frequencies. This frequency either needs to be above that range or quiet.

  • https://www.blog.speculist.com Stephen Gordon

    Mike:

    What’s with women and cold feet? They’re like blocks of ice.

    Karl:

    Most of these devices that are being developed in glass cylinders. The smaller the cylinder, the higher the frequency of sound.

    The developer envisions some of these devices as very small – attached to integrated circuits for cooling in laptops. The pitch of those cylinders should be above the hearing of pretty much anything.