Efficient Diesel Generator with High-zT Thermoelectric Waste Heat Recovery

Mainstream Engineering Corp. (MEC) proposes developing a diesel engine-generator with nanostructured high-zT thermoelectric exhaust waste heat recovery. Commercially available thermoelectric materials have a thermoelectric figure of merit (zT) of approximately 1. Published efforts to harvest exhaust waste heat from a stationary generator using these thermoelectric materials have delivered only very modest gains; about a 0.3% reduction in fuel consumption. To reach more substantial fuel savings will require better (higher zT) thermoelectric materials and tighter integration of the engine, thermoelectric stack, power conditioning unit, and thermal bus. In this Phase I, MEC proposes the further development of a landmark high-zT thermoelectric material recently developed for UAV waste heat recovery. MEC"s thermoelectric material uses nanostructures to induce phonon confinement and thereby improve the ratio of electrical to thermal conductivity. MEC is also in the process of developing a high-efficiency purpose-built 60-hp three-cylinder turbodiesel engine for an Army APU application. The proposed thermoelectric waste-heat recovery system will build off of that engine platform to push the system efficiency considerably beyond the current state-of-the-art for military generators. Phase I includes a thermoelectric material demonstration, component design, and system-level modeling and optimization. Phase II includes the development of a technology demonstrator.