High Temperature Integrated Thermoelectric System and Materials

Current commercial thermoelectric generators (TEG) and materials can only harvest waste energy at temperatures below 250C, with newer systems that might reach 500C(PbTe). Current TE systems are not cost competitive with competing energy harvesting technologies. This is because current methods of fabrication are not compatible with large scale production techniques. Also some of the materials are very expensive, some are toxic, and others are too rare for global adoption. These limitations prevent adoption of TE recovery where waste heat is readily available in industrial processes. These limitations are due largely to a) no suitable high temperature(+1000C) thermoelectric materials, b) mechanical failure caused by thermal expansion mismatch between thermoelectric component and metallization materials, c) design limitations in heat management, and d) cost factors such as raw material, processing, and manufacturing expenses. The above problems will be addressed in this proposal by researching, designing, and development of an integrated thermoelectric system that utilizes high temperature ceramic oxide thermoelectric materials, matched with high temperature ceramic conductive materials, and an energy efficient module design. Phase I research work will be focused particularly on high temperature ceramic oxide thermoelectric materials families that exhibit a potential for a high ZT above 2. The resulting TE devices will have higher energy efficiency, with a goal of +10% by the end of Phase II. They will harvest thermal waste energy at temperatures current modules cannot tolerate. They can also be produced in a low cost manner, and form fitted to different industrial applications. By using ceramic processing, developed over decades of operation, TAM can scale the production of these materials into metric tons, in sharp contrast to current materials. As a result TAM is capable of overcoming technical obstacles as well as meeting market price pressures. The proposed technical approach is focused on increasing the electrical conductivity of oxide ceramic thermoelectric compounds by doping and stoichiometry adjustment schemes of zirconate and titanate compounds. TAM will also utilize state of the art mill processing to reduce materials to nanoparticle size. Commercial application applications and Other Benefits: The best way to first demonstrate the commercial potential of this innovation is in high heat industrial processes. This market would be easier to integrate into than space confined applications, such as vehicles. The novel materials can meet the specific energy and temperature requirements of operation where +1000C waste heat is generated. After proof of principle in Phase I, TAM will conduct prototype testing with our global collaborators in industrial settings. The Glass industry will be a prime example of commercial application. This industry alone has almost $300 million worth of wasted heat energy a year according to recent DOE studies. TEGs can also have applications in steel mills, coal power plants, and many industrial processes where harvesting waste energy at high temperatures for conversion into electricity is very desirable. After the success of commercial applications in industrial processes, TAM believes that vehicles will benefit from the advancement of this technology. TEG applications in automobiles have already been shown to increase fuel efficiency and decrease emissions, but the efficiency is not yet high enough and costs are not yet low enough for industry wide adoption.