Numerical Study on the Performance Evaluation and Thermal Management of Automotive Exhaust Thermoelectric Generator using Pin fins

Abstract

Abstract The utilization of thermoelectric power generators presents a viable prospect for the recuperation of waste heat that results from exhaust gases within the automotive sector. The optimal performance of thermoelectric modules in waste heat recovery applications is heavily dependent on the design of the heat exchanger. The current study employs numerical methods to examine the efficacy of pin-fin configurations on the hot-side heat exchanger surface in enhancing heat transfer and thereby improving the conversion efficiency of TEG. Specifically, the study explores the impact of inline, staggered, and progressive arrangements of pin-fins in the direction of the exhaust stream. The heat exchanger is subjected to variations in fin thickness ranging from 10 mm to 18 mm to improve heat transfer in each configuration. The study conducts simulations on every fin configuration, utilizing three distinct inlet velocities (4 m/s, 6 m/s, and 8 m/s) and five different inlet temperatures (423 K, 473 K, 523 K, 573 K, and 623 K). The assessment of the heat exchanger’s performance is conducted by means of the thermal-hydraulic performance coefficient (THPC) and the temperature uniformity index. Meanwhile, the evaluation of the TEG device’s performance is carried out by estimating its rated power output and the conversion efficiency of TEG. According to the findings, the staggered fin arrangement exhibits the highest Thermal Hydraulic Performance Coefficient (THPC) and power generation capability, while the progressive and inline fin configurations follow in descending order. The utilization of fins with a thickness of 18 mm in a staggered arrangement yields a peak rated power output of 53.42 W. The implementation of pin fins in a staggered configuration within the heat exchanger amplifies the heat transfer from the exhaust gas to the thermoelectric module. Consequently, there is an increase in the output power with respect to the given temperature difference.