Multi-layer performance optimization based on operation parameter-working fluid-heat source for the ORC-VCR system

As an effective energy utilization technology, the ORC-VCR system has great development potential. Multi-layer performance optimization of operation parameter-working fluid-heat source for the ORC-VCR system is carried out. Firstly, parametric analysis and multi-objective optimization are conducted by simultaneously considering thermodynamic, economic and environmental performance in operation parameter layer optimization. Then, working fluid selection under different heat source temperature is performed based on the results of multi-objective optimization in working fluid layer optimization. Finally, the optimal heat source temperature for all working fluids is determined in heat source layer optimization. The results show that with the increase of heat source temperature, generation temperature and condensation temperature of the optimal solution increase and change from centralized to dispersed, while evaporation temperature is always concentrated on the lower limit. COP nearly remains the same. NPV and AER increase continuously. Among the candidate working fluids, HCs have the best comprehensive performance and R602 is almost the optimal working fluid under all heat resource temperature. The optimal heat source temperature for all working fluids is concentrated on high-temperature region. The multi-layer performance optimization method provides a novel idea for improving comprehensive system performance.