The US DoE and most major auto manufacturers are currently pursuing the use of thermoelectrics to replace belt-driven alternators, targeting a 10% increase in fuel efficiency predicated on the development 20% efficient thermoelectric units. Progress has been significantly hampered by the fact that current thermoelectric devices fall well below the targeted 20%.
The automotive industry’s pursuit of thermoelectrics may not be based purely on financial considerations, as the economics are not necessarily compelling for a significant portion of the market unless far greater efficiencies can be obtained, and the price can be reduced below $1/watt. Consequently, we are devoting our resources to other markets in the short-term.
Manufacturers of heavy trucks are also pursuing the use of thermoelectrics as a means toward greater energy efficiency and increased reliability. Of course, trucks only make up a fraction of the overall automotive market (approximately 4%), but they travel far more miles annually than ordinary passenger vehicles, often covering 80,000 miles in a single year.
Clearly, one of the key reasons that the economic case for automotive applications does not appear compelling is that most people are not driving their car for the vast majority of the time. However, employing the same economic model to commercial trucks presents a far more appealing proposition due to the fact trucks are driven significantly more, and are less fuel-efficient.
As in the auto industry, MicroPower thermoelectric generators capturing waste heat produced by the main engine can be used to generate electricity. Though fuel economy and reduced emissions are obvious benefits, the primary driver for the implementation of waste heat recovery systems in the aviation industry is the desire to significantly increase on-board power capabilities without needing to undertake a major engine redesign.
Most of the transportation sectors share common waste heat technologies (reciprocating engines with exhaust pipes or steam systems with cooling pipes) and will share common thermoelectric solutions. Jet engine technology along with mission critical safety will require a careful and lengthy development process.