Thermoelectric Analysis of Automobiles Exhaust Waste Heat Recovery Material – A Simulation Study

Abstract

Abstract Alongside the improvements in renewable fuel technologies, there is also a tremendous increase in research in the field of automobile exhaust waste heat recovery. This is mainly done with the help of thermoelectric generators (TEGs) which use thermoelectric materials (TEMs) as their primary elements. Thermoelectric materials have extensive application in space vehicles. This experience led to its usage for terrestrial automobile waste heat recovery. Usage of TEMs could help in producing accessory power and for fuel savings. Practically the efficiency of system level of automobile exhaust applications is 33% lower than material conversion (device) level. Further the heat exchanger’s performance plays a vital role in the outcome from TEGs. We worked on a theoretical model of heat exchanger with three different profiles of parabolic fin. The fin material which are used to transfer the heat to thermoelectric material is Bismuth Telluride/Antimony Telluride (Bi2Te3/Sb2Te3) for automobile waste heat recovery. The dimensional characteristics of fins for finding the best model were found with the simulation study using ANSYS-Steady state thermal mode. A model of the double finned profile with 8 fins, 8cm length and 1.737cm breadth was proved effective and this profile was simulated using ANSYS-CFX for temperature profiles. Based on the data collected for Bi2Te3/Sb2Te3 super lattice thermoelectric material (TEM) the TEG’s performance was calculated. Double finned parabolic fins resulted in uniformity of temperature distribution. The TEM with a figure of merit (ZT) of 2.4 is showed extraordinary theoretical efficiency, which is of better device level rather than system level.