MIT Develops Devices to Produce Both Energy and Heat

Thus far, solar cells and panels have been focused exclusively on producing electricity from sunlight. Now, experts in the United States announce the development of a new class of light-harvesting devices that may be used for both electricity and heat production.

Experts with the Massachusetts Institute of Technology (MIT), in Cambridge, say that the results of a recent analysis they conducted on the new technology showed encouraging results. The team says that there are numerous advantages to developing this way of harnessing the power of the Sun.

The new solar thermal system is called a parabolic trough, and it contains devices capable of producing electrical currents from temperature gradients. The latter are called thermoelectrics, the team reports.

MIT researchers say that the system has a fairly simple operating principle. Long, curved mirrors are placed in such a way that they focus a beam of sunlight into glass tube that runs between them. A special type of liquid flows through the pipes.

As sunlight is focused on the pipe, the liquid within is heated to high temperatures and turned into steam. This steam can then either drive a turbine to produce electricity, or used directly to heat industrial complexes, office buildings and homes.

According to MIT associate professor of mechanical engineering Evelyn Wang, this investigation “shows a unique opportunity for thermoelectrics integrated within solar thermal systems.” She was the coauthor of a paper describing the research.

Details of how to create these hybrid sunlight-harvesting systems appear in the latest issue of the esteemed scientific journal Solar Energy. The work was carried out by Want and her graduate student Nenad Miljkovic.

An unexpected benefit that the new system would bring would be a significant cost reduction over traditional photovoltaic devices. Thermoelectrics are a lot cheaper than silicon-based solar cells.

Additionally, the thermoelectric devices work excellently at high temperatures, whereas photovoltaic experience a significant dip in performances when exposed to intense heat. “There really is no solar system now to do combined electricity and heat production at high temperature,” Miljkovic adds.

“This is the situation at early stage with every nonconventional idea. […] Overall, the paper shows a nice start and a very capable team behind it,” comments Tel Aviv University professor of mechanical engineering Abraham Kribus, who was not a part of the study.