Research on Heat Transfer Area Characteristic Based on Engine Exhaust Heat Recovery Generating System

Thermal efficiency of conventional automobile engine is only about 30%, and most of other energy is brought away by the exhaust in the form of wasted-heat. Therefore, the heat recovery of engine exhaust has become a hot topic, among which generating electricity through exhaust gas is one of the most important and effective ways. In this research high efficient thermoelectric materials are applied in the thermoelectric generating system. First of all, heat transfer model between car exhaust and cooling water has been established. Then, based on the heat transfer model, in the thermoelectric power generating system the heat transfer area of evaporator has been analyzed and optimized. Finally, based on generating capacity evaluation system, when the engine speed is within the range of common 1700 similar to 2100 Rpm, when the optimal evaporator area range is 0.8m(2) similar to 0.95 m(2) the maximum power output could be achieved.