Advanced Thermoelectric Energy Recovery System in Light Duty and Heavy Duty Vehicles: Analysis on Technical and Marketing Challenges

Thermoelectric materials — materials that exploit a phenomenon in which the application of heat to combination of certain metals induces an electric current- are emerging as potentially important systems for increasing fuel efficiency and decreasing emissions in future automotive vehicles. Thomas seebeck, a German physicist, first noticed the thermoelectric effect in 1821 when he discovered that a voltage was developed in a loop containing two dissimilar metals, provided the two junctions were maintained at different temperature. Some devices have emerged over the years to exploit that property, but have in general been hampered by low efficiency of about 5% with corresponding value of (ZT) equal to approx one (and high cost) Despite the fact that thermoelectric devices are compact, quite, rugged, stable and very reliable; thermo electrics have found only in niche applications and their wide widespread acceptance depends upon discovery of new materials with high conversion efficiency. The issue of thermoelectric efficiency for automotive application is examined from the standpoint of what material figures of merit (FOMs) will enable solid-state devices to compete with conventional electricity generator or vapor compression refrigerators. It is estimated that FOMs of (ZT) equal to or greater than 8 will be required. Some of the emerging new bulk materials may eventually reach that level of performance. How ever layered thin — film structures based on two — dimensional quantum wells and short period super lattices appear to have qualities will enable rapid attainment of FOMs that signal economic competitiveness.