Prospects for Implementation of Thermoelectric Generators as Waste Heat Recovery Systems in Class 8 Truck Applications

Abstract

With the rising cost of fuel and increasing demand for clean energy, solidstate thermoelectric (TE) devices are an attractive option for reducing fuel consumption and CO2 emissions. Although they are reliable energy converters, there are several barriers that have limited their implementation into wide market acceptance for automotive applications. These barriers include: the unsuitability of conventional thermoelectric materials for the automotive waste heat recovery temperature range; the rarity and toxicity of some otherwise suitable materials; and the limited ability to massmanufacture thermoelectric devices from certain materials. One class of material that has demonstrated significant promise in the waste heat recovery temperature range is skutterudites. These materials have little toxicity, are relatively abundant, and have been investigated by NASAJPL for the past twenty years as possible thermoelectric materials for space applications. In a recent collaboration between Michigan State University (MSU) and NASAJPL, the first skutteruditebased 100 W thermoelectric generator (TEG) was constructed. In this paper, we will describe the efforts that have been directed towards: (a) enhancing the technologyreadiness level of skutterudites to facilitate mass manufacturing similar to that of Bi2Te3, (b) optimizing skutterudites to improve thermaltoelectric conversion efficiencies for class 8 truck applications, and (c) describing how temperature cycling, oxidation, sublimation, and other barriers to wide market acceptance must be managed. To obtain the maximum performance from these devices, effective heat transfer systems need to be developed for integration of thermoelectric modules into practical generators.