Thermoelectric generators for defense applications

J.C. Bass, A. Kushch, V. Jovanovic, N. Elsner

Hi-Z Technology, Inc., 7606 Miramar Road, San Diego, CA 92126 4210, U.S.A.

A program to demonstrate compact thermoelectric generators (TEGs) is being completed. Initial results were presented at the ICT 2002. This is work done on a Phase II SBIR for TACOM-ARDEC (Picatinny Arsenal). Units operating on logistics fuel have output power of 300mW, 3.5W and 15 to 20W. These can be used as primary power sources in place of batteries, or the output can be use for battery chargers.

Hi-Z is currently performing the Phase I of a Navy SBIR study in which it is using its thermoelectric generating modules in developing a miniature energy harvesting system to provide power for shipboard health monitoring wireless sensors. These sensors can be used to detect cracks, corrosion, impact damage, and temperature excursions as part of the Condition Based Maintenance. These power-harvesting modules can be used to replace or augment batteries as electrical power sources. In order to satisfy the small design-volume requirement of one cubic inch, Hi-Z is using its emerging thin-film quantum well thermoelectric technology that will provide a factor of four increase in efficiency and a large reduction in volume over the bulk bismuth-telluride based thermoelectrics.

Hi-Z is currently conducting two other projects focused on waste heat recovery systems for automotive applications, both of which have potential application to military vehicle electric power needs.

Under the DOE (Office of Heavy Vehicle Technologies) Hi-Z and PACCAR have developed a 1 kW engine exhaust powered generator. It has undergone testing in a test cell and mounted on a test truck equipped with a 550 HP Caterpillar engine. The generator went through durability testing equal to 408,000 miles without any evidence of degradation. The current 1 kW TEG design employs bulk bismuth-telluride. It is expected that multi-kilowatt systems in the range of 2 kW to 5 kW will be possible to fabricate when the new quantum well materials are available. Under the same contract Hi-Z has modified a 200W thermoelectric waste heat recovery system for a hybrid vehicle, which is under development at Ohio State University.

Waste heat recovery from a smaller vehicle is being pursued with Clarkson University under the New York State Energy Research and Development Authority (NYSERDA). The projectís goal is to develop a thermoelectric generator for a GM Sierra 2000 truck, driven by a V8, 270 HP gasoline engine.

Both thermoelectric generators are using engine exhaust as the heat source and engine coolant to cool the cold side of the TEG.

Also, Hi-Z is pursuing an auxiliary power unit development. There is no principal difference between the generator that converts diesel/IC engine exhaust heat to electricity and a TEG driven by the exhaust of a fossil fuel burner. Under the UA Army (CECOM) funding Hi-Z is developing a diesel driven 500W high efficiency power generator for military applications.