Industrial Solid-State Energy Harvesting: Mechanisms and Examples

This paper explores the potential for solid-state energy harvesting in industrial applications. In contrast to traditional heat recovery, the output of solid-state devices is electricity, which can be readily used in virtually any plant. The progress in harvesting waste heat via thermoelectric and thermionic generators is described. With second law efficiencies now approaching 50% and 80% respectively, we show that these technologies are on the cusp of practical use. Finally, we present an example of energy harvesting using thermionic devices in an industrial application. The example considers energy harvesting from a furnace at a glass manufacturing facility where exhaust gases are discharged at about 2,400 o F and where there are no viable uses for recoverable heat. An optimal configuration of thermionic devices is shown to be capable of recovering nearly 1/3 of the available exergy in the exhaust gases as electrical energy.