thermoelectrics

A developing technology. Since solar energy 'raining' on Nicaragua amounts to 1 kW per square meter this may prove important in its future.

From Boston Globe / March 24, 2008:

In a thermoelectric circuit, heat applied to one end causes electrons to move to the other end, creating an electric current. The reverse is also true: Applying a current to the device will carry heat from one side to the other, where it is ejected. Thermoelectric devices are already used to power NASA space shuttles, while companies have used their heat-transferring properties to create cooling systems without the polluting chemicals used in most air conditioners.

More widespread adoption has stalled, however, because most materials that conduct electricity also conduct heat and therefore can lose a lot of energy to leakage.

In the experiment, published Thursday in the online version of the journal Science, scientists took a substance commonly used in thermoelectrics, bismuth antimony telluride, and crushed it into nanoparticles. They then heated the powder and pressed it back together, creating a new structure that allowed electrons to move freely but impeded the flow of heat. The new material performed 40 percent more effectively than existing compounds, according to the study.

The researchers have formed a Newton-based company, GMZ Energy, Inc., to develop the technology. They envision a future where thermoelectric coolers replace conventional refrigerators, and thermoelectric power generation becomes a standard part of the design of any green home. That would require much greater improvements in efficiency than those achieved by the MIT-Boston College team. But with oil prices skyrocketing "efficient" becomes a relative term.