Bulk Nano Structured Thermoelectric Materials for Building Air Conditioning and Commercial Refrigeration Applications

High-efficiency, bulk nano-structured thermoelectric composite materials with high performance (ZT ~ 3 or 4) are needed for refrigeration applications in buildings. The concept of improving ZT by making nano-structured thin film materials in the form of quantum wells and dots has been demonstrated. Instead, in this project, nano-structured bulk thermoelectric materials will be processed via powder metallurgy (P/M), leading to ease of fabrication and lower costs. The approach combines three innovations: (1) nano powders of Bi2Te3- Bi2Se3 made from high purity ingots, (2) a novel dispersion process of matrix and additives, and (3) the compaction of these powders into high performance thermoelectric materials using Dynamic Magnetic Compaction (DMC), a high density powder compaction method. Such materials are designed to yield nano-structured modulations that will lower thermal conductivity without sacrificing electrical conductivity. Commercial Applications and other Benefits as described by the awardee: The thermoelectric devices should find use in building air conditioning and commercial refrigeration applications, replacing current cooling methods that depend on the mechanical vapor compression cycle (VCC) of refrigerant gas. Thermoelectric materials offer environmentally-friendly solutions for cooling.