GMZ Energy gets thermoelectric

Newton, Mass.-based startup GMZ Energy is heading for the commercial market with a new thermoelectric material that it says can turn waste heat into electrical power.

Last month, the company raised an undisclosed seed investment from Kleiner Perkins Caufield & Byers (see Solar jumps to the front of the pack).

GMZ said its nanotechnology-based material would initially be used in cooling applications, but longer-term it could also be used on car exhausts and in solar thermal panels.

It's made from bismuth antimony telluride, a semiconductor alloy that has been used in commercial devices since the 1950s.

GMZ said its already producing the material in pre-production volume at its multi-ton manufacturing facility in Newton.

"It's actually very low tech. We ball-mill into nanoparticles and then compact them into bulk form. And, of course, in the process we maintain the structure we want," professor Gang Chen, co-founder of GMZ Energy, told the Cleantech Group.

Chen is a professor of professor of mechanical engineering at the Massachusetts Institute of Technology.

He teamed up with Mike Clary, an entrepreneur in residence at Kleiner Perkins, and Zhifeng Ren, a professor of physics at Boston College, to form the G-M-Z of GMZ Energy.

"The current market is mostly in the cooling market," said Chen. "For example, in automobile carseats."

When the alloy is crushed to make the material, and then heated and pressed back together, the process disburses the nanoparticles, which scatter incoming heat.

Take a look at a close-up of the material here >>

The company said the material can slow down heat flow while allowing electrical flow, redirecting the heat to drive electrons.

In an example of thermoelectricity, if you heat one end of a wire, it causes electrons to move to the cooler end, producing an electric current. In reverse, applying a current to the same wire will carry heat away from a hot section to a cool section.

The early applications for GMZ's new material, in addition to carseats, will be in appliances like refrigerators and air conditioners.

Right now the material can handle up to 250 degrees Celsius, but once the material can handle even higher temperatures, it could be used for a number of interesting applications.

"Combine the temperature with heat from the automobile exhaust and generate electricity," said Chen. "So it's not an insulation purpose material, it's a power generation purpose material."

"Automobile driving efficiency is less than 20 percent, the rest goes to waste," he said, mostly in the form of heat. "Roughly one third of this goes through the tailpipe."

If you can capture that heat and use it to power the vehicle, Chen said you would increase the car's fuel efficiency.

The company said the material could also be used as part of a solar thermal system.

Kleiner Perkins could potentially play matchmaker on that front, as it's one of the investors in Palo Alto, Calif.'s Ausra, a developer of utility-scale solar thermal technology (see Solar thermal could supply most of the U.S. grid, says Ausra).

Last September, Ausra raised more than $40 million in funding from Khosla Ventures and Kleiner Perkins.

GMZ, which said its manufacturing method is low cost and could be scaled for mass production, announced that its material is in an advanced testing stage at certain U.S. and Asia-Pacific manufacturers.

The company said the material is also being sampled by early customers.

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