Improvement in Flow Distribution for Effective Thermal Management in Thermoelectric Generator for Waste Heat Recovery

In an automobile, only one-third of the total fuel energy is used for propulsion, and the remaining two-third is lost to engine coolant and the exhaust as waste. Thermoelectric generators (TEG) demonstrate huge potential in automotive applications by recovering the exhaust waste heat and converting it into direct electric power. TEG helps escalate the engine’s fuel efficiency. However, extracting waste heat from automobile exhaust using TEG manifests practical difficulties attributed to thermoelectric materials, design, and operating conditions. Ineffective configurations and heat exchanger designs lead to non-uniform flow and temperature distribution on the hot and cold sides of TEG, causing undesirable power output, which lowers the entire system’s efficiency. In this study, the flow distribution of exhaust gas through the automotive TEG with pin fin heat exchanger is simulated using Computational Fluid Dynamics (CFD). Improvement in the flow pattern using passive flow distributors such as guide vanes at different angles is analyzed to attain the temperature uniformity through the hot heat exchanger surface. A detailed analysis of flow distribution and its influence on the local and average temperature distribution is presented. Results provide critical design recommendations to improve the flow distribution in an automotive TEG for exhaust waste energy recovery.