Optimization of the cold-side heat exchanger design to improve the performance of the motorcycle exhaust thermoelectric generator

Abstract

This study optimizes the main parameters of the cold-side heat exchanger (CHE) longitudinal fin, including fin quantity (N_f), fin thickness (T_f), and fin height (H_f), to enhance the performance of motorcycle exhaust thermoelectric generator units (TGUs) utilizing the computational fluid dynamics approach. The investigation shows that these parameters significantly affect the dissipation area of the CHE heat and the outside air velocity distribution in fin gaps, resulting in the fluctuation of TGU output power. The output power increases with respect to H_f; nevertheless, it first increases as N_f and T_f increase but decreases dramatically when N_f or T_f becomes too large. Besides, H_f significantly affects output power, and its impact is almost independent of T_f and N_f, and vice versa; meanwhile, T_f and N_f have a strong relation. This study proposes two H_f of 40 and 60 mm along with the optimal T_f of 1 mm and N_f of 29, providing significantly high output power, low weight, and compact size for TGU. This work contributes insight into the effect of CHE parameters on the TGU performance, and it is a crucial case study for selecting suitable heat sink parameters for TGU, considering practical requirements and conditions.