Research on Engine Exhaust Energy Recovery by a Heat Pipe Exchanger with a Semiconductor Thermoelectric Generator

A heat pipe exchanger was adopted to recover the engine exhaust energy and its internal gas pressure. Velocity and temperature distribution were obtained with the computational fluid dynamics software called ‘FLUENT’. Based on the simulation results, the structure of the exchanger was improved, and its working performance was verified by experiments. The experiments showed that the pressure loss of the exchanger is only about 850 Pa, which has less influence on engine performance and is in good agreement with the simulation, as this is a more homogeneous internal air temperature distribution with better exchanger’s efficiency. And by measuring the output power under the temperatures 335 K, 355 K, 375 K and 395 K, respectively, at the cold end of the semiconductor thermoelectric generator, it was found that it had the same cold end temperature and the temperature difference was over 100 K. The output power increases rapidly at first and then continues to grow but at a decreasing rate, and the largest output power is 75.6 W when the cold end temperature is 335 K with the temperature difference of 380 K, and in addition to this it was observed that under the same temperature difference, the lower cold end temperature is the larger the output power.