|TG16. Click to enlarge.|
GMZ Energy, a developer of high temperature thermoelectric generation (TEG) solutions, has introduced the TG16-1.0, a new thermoelectric module capable of producing twice the power of the company’s first product, the TG8-1.0. By doubling the power density, GMZ’s new module substantially increases performance while maintaining a minimal footprint.
GMZ has been using TG8 modules in developing vehicular thermoelectric generators for the Bradley Fighting Vehicle (1 kW TEG) as well as to design and to integrate a light-duty vehicle TEG into a Honda Accord as part of a DOE-funded project. (Earlier post.)
GMZ Energy’s proprietary platform technology enables the low-cost manufacturing of bulk thermoelectric materials. GMZ is the exclusive licensee of a broad patent held by the Massachusetts Institute of Technology and Boston College covering the manufacturing of high ZT (a dimensionless figure of merit) thermoelectric materials with a nano-structure of less than 1 micron.
The company’s patented nano-structuring process reduces thermal conductivity while maintaining electrical conductivity, enhancing the ZT by 30-60% across multiple classes of thermoelectric materials, including bismuth telluride, lead telluride, skutterudites, silicon germanium, and half-Heusler materials.
GMZ uses nano-engineered half-Heusler (HH) thermoelectric materials (earlier post) in its current modules, and has filed a broad patent to protect the use of half-Heusler compounds for TE applications.
Although these materials (ferromagnetic intermetallic alloys with a strong crystal structure that allows great stability at high temperatures) have a ZT lower than some other TE materials such as Skutterudites, the mechanical strength and the reliability of HH compensates for this deficit, according to GMZ.
The unique properties of half-Heusler materials combined with proprietary module fabrication techniques enable scalable, low-cost manufacturing of half-Heusler modules yielding a cost per watt below $1.00 and a high power density, the company says.
In June, GMZ reported the successful demonstration of a TEG designed for automotive waste heat recapture and built with the TG8 modules. (Earlier post.) The unit generated an output power well in excess of its 200 watt design goal. GMZ Energy built the TEG as a part of an ongoing vehicle efficiency research program sponsored by the US Army Tank Automotive Research, Development and Engineering Center (TARDEC) and administered by the Department of Energy (DOE).
|Typical Performance Values|
|Hot side temperature||400 ˚C||500 ˚C||600 ˚C|
|Cold side temperature||100 ˚C||100 ˚C||100 ˚C|
|Peak Power (W)||2.6||5.9||4.8||10.3||7.2||15.3|
|Voltage at Peak Power (V)||0.53||2.3||0.75||2.9||0.84||3.8|
|Open Circuit Voltage (V)||1.03||4.4||1.41||5.9||1.73||7.5|
|Internal Resistance (Ω)||0.095||0.82||0.1||0.87||0.105||0.91|
TG16. The TG16 can produce 15 Watts of power when a temperature gradient of 500 °C is applied, assuming a 100 °C cold side temperature. (The TG8 can produce 7.2 Watts of power when a temperature gradient of 500°C is applied, assuming 100 °C cold side temperature.) The small size, high power output and reliability of this device make it suited for local, high reliability power generation from waste and primary heat sources.
The added power density of the TG16 makes it particularly useful for applications with very high temperature heat flows, GMZ said. The device has been implemented successfully in applications with heat flows in excess of 1000 °C. The TG16’s lower thermal resistance maintains the hot-side temperature of the module below 600°C even with a high-temperature exhaust stream present.
This new module will augment the TG8 module, broadening the product line and enabling dramatic efficiency improvements and new functionalities in products requiring high power density. The TG16-1.0 is currently available for sampling to qualified OEM manufacturers.
Founded in 2006, GMZ’s investors include Kleiner Perkins Caufield & Byers, BP Alternative Energy, I2BF, Mitsui Global Investment, and Energy Technology Ventures, a joint venture between General Electric, NRG Energy, and ConocoPhillips.