Multiphysics Modeling of an Integrated Thermoelectric Generator

An innovative pin-fin integrated thermoelectric device (iTED) is numerically modeled to quantify the effect of thermal flow conditions, namely inlet temperature (\( T_{\textrm{in}} \)) and Reynolds number (Re), as well as electrical load resistance (\( R_{\textrm{load}} \)), on the thermal-electric-fluid coupled performance. Quantification of the simultaneous thermal-fluid-electric behavior of the iTED was pursued through the implementation of an explicitly-coupled solution algorithm developed in ANSYS Fluent's User Defined Scalar (UDS) environment. The effects of \( T_{\textrm{in}} \), Re, and \( R_{\textrm{load}} \), which were varied between 350 and 650 K, 3,000 and 15,000, and 0.01 and \( 10^{6} \% \) of the internal device resistance (\( R_{\textrm{int}} \)), respectively, on the open-circuit voltage, current, power output (\( \dot{W} \)), heat input, pumping power, device thermal conversion efficiency (\( \eta \)), and dimensionless performance index (\( \zeta \)), were evaluated for a fixed cold-side temperature of 300 K. The performance of the iTED was then compared to that of a conventional TEG. At a \( T_{\textrm{in}} \) of 650 K, the iTED achieved a maximum \( \dot{W} \) of 23.9 W when \( R_{\textrm{load}}=R_{\textrm{int}} \) at a Re of 15,000, a maximum \( \eta \) of \( 8.1\% \) when \( R_{\textrm{load}} \) < \( R_{\textrm{int}} \) at a Re of 10,000, and a maximum \( \zeta \) of 7.8 at a Re of 3,000. In comparison, the conventional device achieved a \( \dot{W} \) of 5.2 W, an \( \eta \) of 2.9%, and a \( \zeta \) of 1.6 at the same \( T_{\textrm{in}} \) and Re of 15,000, 6,000, and 3,000, respectively. The proposed multiphysics numerical modeling illustrates marked improvements via device restructuring.