High-performance nanotech materials arrayed on a flat panel
platform demonstrated seven to eight times higher efficiency than previous
solar thermoelectric generators, opening up solar-thermal electric power
conversion to a broad range of residential and industrial uses, a team of
researchers from Boston College and MIT report in the journal Nature Materials.
Two technologies have dominated efforts to harness the power
of the sun’s energy. Photovoltaics convert sunlight into electric current,
while solar-thermal power generation uses sunlight to heat water and produce
thermal energy. Photovoltaic cells have been deployed widely as flat panels,
while solar-thermal power generation employs sunlight-absorbing surfaces
feasible in residential and large-scale industrial settings.
Because of limited material properties, solar thermal
devices have heretofore failed to economically generate enough electric power.
The team’s introduced two innovations: a better light-absorbing surface through
enhanced nanostructured thermoelectric materials, which was then placed within
an energy-trapping, vacuum-sealed flat panel. Combined, both measures added
enhanced electricity-generating capacity to solar-thermal power technology,
said Boston College Professor of Physics Zhifeng Ren, a co-author of the paper.
“We have developed a flat panel that is a hybrid capable of
generating hot water and electricity in the same system,” said Ren. “The
ability to generate electricity by improving existing technology at minimal
cost makes this type of power generation self-sustaining from a cost
standpoint.”
Using nanotechnology engineering methods, the team combined
high-performance thermoelectric materials and spectrally-selective solar absorbers
in a vacuum-sealed chamber to boost conversion efficiency, according to the
co-authors, which include MIT’s Soderberg Professor of Power Engineering Gang
Chen, Boston College and MIT graduate students and researchers at GMZ Energy, a
Massachusetts clean energy research company co-founded by Ren and Chen.
The research was supported as part of the Solid State Solar-Thermal Energy
Conversion Center,
an Energy Frontier Research
Center funded by the U.S.
Department of Energy. Other BC members of the research team are doctoral
candidates Bo Yu, Yi Ma, and Xiaowei Wang, post-doctoral researcher Xiao Yan
and facilities manager Dezhi Wang, as well as Bed Poudel, PhD ’07, now a
researcher at GMZ Energy.
The findings open up a promising new approach that has the potential
to achieve cost-effective conversion of solar energy into electricity, an
advance that should impact the rapidly expanding residential and industrial
clean energy markets, according to Ren.
“Existing solar-thermal technologies do a good job generating
hot water. For the new product, this will produce both hot water and
electricity,” said Ren. “Because of the new ability to generate valuable
electricity, the system promises to give users a quicker payback on their
investment. This new technology can shorten the payback time by one third.”
