There are solar panels that generate electricity and those that absorb heat
for hot water. And now researchers at MIT and elsewhere say they’ve made
progress on using the sun’s heat to make electricity.
In a paper published
in Nature, the researchers describe the progress they’ve made on a
nanostructured material that improves on the heat-to-electricity conversion rate
over existing thermoelectric devices.
Kraemer (right) show a prototype of a solar thermoelectric generator.
The researchers envision that this solid-state material could be packaged
either as a stand-alone thermoelectric generator or added onto existing solar
hot water systems to make electricity. “Our work opens up a promising new
approach which has the potential to achieve cost-effective conversion of solar
energy into electricity,” the researchers said in their paper.
Massachusetts Institute of Technology professor Gang Chen said a
thermoelectric generator in the shape of a flat plate could be placed inside a
glass vacuum tube and covered with a black plate of copper to absorb heat. The
other side of the thermoelectric device is exposed to the ambient air, creating
a temperature difference on the two sides of the plate, which will induce a flow
Thermoelectric devices made of different materials are already used for
different applications, such as portable coolers or to cool off car seats. But
there are a number of researchers and companies seeking to improve the
heat-to-electricity conversion efficiency to open up thermoelectric devices to
more applications, such as using waste heat from car exhaust systems to power
In their paper, the researchers said they have achieved 4.6 percent peak
efficiency, which is seven to eight times better than previous results with
solar thermoelectric generators.
If the research, which is funded by the Department of Energy, pays off, it
could reduce the cost of solar power significantly and enter the market by
piggybacking on the existing solar hot water industry. “It can be a
game-changing thing,” Chen said in a statement.