Jun 1, 2009

By UCLA Samueli Newsroom

Jean-Pierre Fleurial,
Jet Propulsion Lab/Caltech

10:30 a.m. to Noon, June 5
2101 Engineering V building
Refreshments Will Be Served

Thermoelectric Technology: Challenges and New Application Opportunities

Thermoelectric (TE) power sources have consistently demonstrated their extraordinary reliability and longevity for deep space missions (67 missions to date, up to 30 years of life) as well as terrestrial applications where unattended operation in remote locations is required. They are static devices with a high degree of redundancy, no electromagnetic interferences, with well documented “graceful degradation” characteristics and a high level of scalability. They are also tolerant of extreme environments (temperature, pressure, shock and radiation).

The development of new, more efficient materials and devices is the key to improving existing space power technology and expanding the range of terrestrial generators, for both stand-alone and hybrid applications. There exists a wide range of heat source temperatures for these applications, from low grade waste heat, at 300 – 400 K, up to 900 to 1100 K, such as in the heat recovery from a processing plant of combustible solid waste.

For the U.S. manufacturing industry alone, each year more than 600 terawatt-hour of waste heat energy are considered to be an opportunity for waste heat recovery. The automobile industry has also recently developed a strong interest in a waste exhaust heat recovery power source operating in the 400 to 900 K temperature range to supplement or replace the alternator and thus decrease fuel consumption and concurrently reduce greenhouse gas emissions.

One of the approaches is to develop and integrate a TE power generator into a vehicle’s electrical system to convert the engine waste heat directly to electricity and improve fuel economy by as much as 10 percent, a significant
savings over the useful life of today’s vehicles.
Some key challenges and barriers to the successful development and implementation of TE waste heat recovery technology include:

a) improving TE materials conversion efficiency in the temperature range of interest;
b) developing rugged, reliable high temperature TE multi-couple module technology;
c) optimizing heat transfer to/from the TE modules;
d) surviving the vehicle operational thermal
cycling, vibration stress and strain environment;
e) leak proof heat transfer fluid connections;
f) integrating a dedicated radiator for the TE Generator;
g) minimizing TE generator system weight;
h) ensuring acceptance of this revolutionary technology and;
i) costs.

We highlight recent improvements in the conversion efficiency of high temperature materials, summarize progress in transitioning thermoelectric technology to a more flexible, modular array configuration and discuss technical challenges, competing technologies and promising application opportunities.