Dynamic performance analysis of transcritical power cycle with preheater and regenerator using CO2-based binary zeotropic mixtures

The CO2 transcritical Rankine cycle is considered as an ideal solution in the application of waste heat recovery due to its safety, environmental friendliness and compactness characteristics. In this work, for the heat recovery from internal combustion engine, a dynamic model of an improved CO2 transcritical Rankine cycle system containing both a preheater and regenerator with CO2-based binary zeotropic mixtures as working fluid is developed. The performance of CO2 transcritical power cycle with preheater and regenerator was compared and analyzed for mixture working fluids with different proportions under the disturbance of heat source conditions and system input parameters, which can provide references for system control strategy to ensure efficient and stable operating conditions when selecting control variables. The results show that there is a certain pump speed to obtain the optimal value of the net output work and thermal efficiency of the system. And the net output power and thermal efficiency of system with CO2-based binary zeotropic mixtures at optimum point are higher 6. 34 kW and 2.19% respectively than pure CO2 as working fluid by adjusting pump speed.