The Potential for Thermo-Electric Regeneration of Energy in Vehicles

The pursuit of improved fuel economy is becoming an increasingly important objective for automotive manufacturers. The field of thermo-electrics is highlighted as a promising technology. The figure of merit, Z is the primary measure of the effectiveness of a thermo-electric material, and the values now being offered by researchers have reached the level where new applications become attractive. It is feasible to consider such modules incorporated into a thermoelectric generator to recover waste heat from exhaust gas flow – an available energy stream that has traditionally been neglected as unusable. As a precursor to a costly experimental study it is desirable to accurately simulate the application of a thermo-electric system to a vehicle exhaust to understand both the feasibility and potential drawbacks.

A numerical model of a vehicle able to support transient analysis is presented Transient modelling of the exhaust flow is considered of considerable importance to the validity of the simulation study, an aspect that does not appear to have been considered in previous studies. An explicit time-marching numerical model has been developed to capture the transient performance of a thermo-electric generator. The heat exchange model is coupled with a quasi-static vehicle model to allow simulation of the effects on vehicles.

Initial studies indicate that with an output of around 1.3kW the alternator of a small passenger vehicle could be replaced.