Modeling and Analysis of Thermoelectric Generators for Diesel Engine Exhaust Heat Recovery System

Abstract

The paper focuses on the performance of thermoelectric generators (TEGs) in different positions and under different running conditions. Three-dimensional numerical models of two designs of exhaust heat recovery systems were studied in which two kinds of heat exchangers were designed, and their flow and temperature field characteristics were analyzed. Thermoelectric generators were arranged on the upper and lower surfaces of the heat exchanger, and their thermoelectric output performance was investigated under different engine running conditions (i.e., medium load, high load, and full load). The results showed that the surface temperature of the heat exchanger with vortex rods is higher and more uniform than that of the heat exchanger without vortex rods. Although the backpressure increases for the heat exchanger design with the vortex rods, this is in the order of 1,392 Pa in the condition of full load and therefore negligible. One can see that the position of TEGs and diesel engine running conditions greatly impact the performance of TEGs. Compared with the heat exchanger without vortex rods, the heat exchanger with vortex rods could supply a higher open-circuit voltage at the corresponding position. The output characteristics of TEGs are better, as the temperature is higher in a full load condition.