Research on the simulation of cascade utilization of engines´ waste heat based on TEG and ORC

A novel system combined thermoelectric generators (TEG) with organic Rankine cycle (ORC) systems was designed for cascade utilization of the waste heat of engines. R113 is used as the working fluid in the ORC system which is coupling with the TEG devices, and the simulation of system performance was carried out under different system parameters when R113 worked under subcritical conditions, so the optimization of parameters of both TEG and ORC can be achieved. The results show that, the overall system efficiency of the combined TEG-ORC system increase significantly compared with the traditional ORC. Under the fixed ORC working parameters, there is a maximum efficiency point within the Tη range studied, and efficiency will increase monotonically in a small scale as the Tc decreases, and the larger the high-temperature-side UA is, the higher the maximum efficiency point of the system achieves. While under the fixed ORC working parameters, thermal efficiency of the system is much higher due to its higher evaporator pressure and lower condenser pressure. Compared with the conventional ORC system, additional 2.61kW output can be provided by the TEG, and it can lower the external input to support the system and make a considerable contribution to the overall system efficiency.