Thursday, September 30, 2010

Turning waste heat into power

Image: A "forest" of molecules holds the promise of turning waste heat into electricity. UA physicists discovered that because of quantum effects, electron waves traveling along the backbone of each molecule interfere with each other, leading to the buildup of a voltage between the hot and cold electrodes (the golden structures on the bottom and top).

( Daniel Stolte, University of Arizona )

"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.

Car or factory exhaust pipes could be coated with the material, less than 1 millionth of an inch thick, to harvest energy otherwise lost as heat and generate electricity. ...

via Turning waste heat into power.

If we are now in the Internet age, the next age could be the nano-age.
In its broadest definition, "nanotechnology" refers to the construction and use of structures and devices that range in size from one to 100 nanometers, a nanometer being one billionth of a meter. How small is this? A dot one nanometer in diameter would be approximately 100,000 times smaller than the diameter of a human hair. A typical virus measures 100 nanometers across. Nanometer-sized features on a computer chip would be about a thousand times smaller than the micrometer-sized features on today's chips. This would mean that all the information stored in the Library of Congress could be contained in a computer the size of a sugar cube. By today's standards, that's a supercomputer that can fit in the palm of your hand.

The arrival of the nano-age will mean that humans can process matter on a molecular scale; that is, we will be able to build things atom by atom or molecule by molecule.

When construction takes place at the molecular level, there is virtually no limit to the shape and size of the objects and devices you can make. The nano-age is coming, but how soon this technology arrives will depend upon scientific research.

via Eureka Alert

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