Turning Waste Heat Into Power

ScienceDaily ^ | Oct. 3, 2010 | ScienceDaily staff

[Freeport]

What do a car engine, a power plant, a factory and a solar panel have in common? They all generate heat -- a lot of which is wasted.

University of Arizona physicists have discovered a new way of harvesting waste heat and turning it into electrical power.

Using a theoretical model of a so-called molecular thermoelectric device, the technology holds great promise for making cars, power plants, factories and solar panels more efficient, to name a few possible applications. In addition, more efficient thermoelectric materials would make ozone-depleting chlorofluorocarbons, or CFCs, obsolete.

The research group led by Charles Stafford, associate professor of physics, published its findings in the September issue of the scientific journal, ACS Nano.

"Thermoelectricity makes it possible to cleanly convert heat directly into electrical energy in a device with no moving parts," said lead author Justin Bergfield, a doctoral candidate in the UA College of Optical Sciences.

"Our colleagues in the field tell us they are pretty confident that the devices we have designed on the computer can be built with the characteristics that we see in our simulations."

"We anticipate the thermoelectric voltage using our design to be about 100 times larger than what others have achieved in the lab," Stafford added.

Catching the energy lost through waste heat has been on the wish list of engineers for a long time but, so far, a concept for replacing existing devices that is both more efficient and economically competitive has been lacking.

Unlike existing heat-conversion devices such as refrigerators and steam turbines, the devices of Bergfield and Stafford require no mechanics and no ozone-depleting chemicals. Instead, a rubber-like polymer sandwiched between two metals acting as electrodes can do the trick.

[Freeport]

Well, well. An undergraduate doing independent study may have figured out how to get a boat load of electrical energy back from waste heat. I learned more doing 'IS' than in my course work since I could mix and match disciplines. More IS needs to be done in my opinion.

[El Sordo]

Still kinda neat.

[MHGinTN]

"Unlike existing heat-conversion devices such as refrigerators and steam turbines, the devices of Bergfield and Stafford require no mechanics and no ozone-depleting chemicals. Instead, a rubber-like polymer sandwiched between two metals acting as electrodes can do the trick."

Mmmm, sandwiches!

[taxcontrol]

Later in the article, it talks about powering two hundred 100 watt bulbs from the waste heat from an automobile. That would be a recovery of about 20 Kw. A significant jump and could push the effeciency past 50%. It would be really interesting to see this combined with a steam engine.

[filospinato]

Let me know when I can ditch my alternator, or will this only ever be able to power my dome light.

[r9etb]

Later in the article, it talks about powering two hundred 100 watt bulbs from the waste heat from an automobile. That would be a recovery of about 20 Kw. A significant jump and could push the effeciency past 50%. It would be really interesting to see this combined with a steam engine.

I'd be interested to know what would push the efficiency so high in the first place. The best thermocouples in use today run at about 5-10% efficiency.

IMO. the most important point in this article is that they haven't even built one of these items yet. They've got a nifty model and a 2nd-hand quote saying that some guys he knows "are pretty confident that the devices we have designed on the computer can be built...."

Well, we'll see. Sounds to me like grant application deadlines are looming.

[Flightdeck]

ZT=?

Sorry, there isn’t enough high-quality (i.e. high temperature) waste energy to do much with.

[Squawk 8888]

That level of recovery would be more than enough to eliminate the alternator, MOF the waste heat could easily be used to drive a 20hp electric motor to supplement the engine power.

[tired1]

A molecular benzine aircraft wing. cool!

[benewton]

“IMO. the most important point in this article is that they haven’t even built one of these items yet. They’ve got a nifty model and a 2nd-hand quote saying that some guys he knows “are pretty confident that the devices we have designed on the computer can be built....”

Well, we’ll see. Sounds to me like grant application deadlines are looming. “

I think that covers it.

I do use modeling software, but I always prototype and characterize the resulting circuit. My bad: I don’t have total faith in models (see global warming)(.

[SuziQ]

Sounds like a good application for industrial use. Why send all that heat out into the atmosphere, when it could be used IN the plant, and reduce the cost of other energy needs.

[Pessimist]

Solar panels do not generate heat.

[WOBBLY BOB]

if we could only harness the heat of Algore’s 2nd chakra...

[wbill]

Solar panels do not generate heat.

You noticed this too? :-)

Good idea to try and recapture some energy. I've always wondered what could be done with all of the waste heat that's radiated out of our datacenters.

[taxcontrol]

I’m wondering if this can take out enough heat to go back to an air cooled engine. If you can take away the efficency losses due to water pump, radiator, and alternator; a significant gain in efficiency could be had right there.

[Smokin' Joe]

You need to think harder. Imagine power plant cooling towers that generated more electricity, for instance.

[padre35]

Good idea.

[Smokin' Joe]

I have more! (but I want to make some money off of them)

[Pessimist]

It is a goodidea. But it’s not very easy to efficiently convert it to electricity.

A better bet is for “hotel” load (hot water, heat, etc).

[RadiationRomeo]

If I remember correctly they use at least some of the hot water generated by the Nuke plant near Sandusky Ohio to heat a whole lot of greenhouses. That was smart.