Working fluid selecting of the enhanced DPORC system with double-layer multi-objective optimization based on the improved WRSR method considering three pinch point temperature differences ratios

Abstract

This paper centered on the dual-pressure ORC (DPORC) and its derived enhanced DPORC (SRPH-DPORC, DRP-DPORC) to surmount the constraints of pinch-point temperature difference analysis, fixed-weight optimization, and the fuzzy quantization classification of the working fluid. Thermodynamic, economic, environmental, and sustainable performance in the system was explored from the perspective of three pinch-point temperature difference ratios. The enhanced weighted rank-sum ratio (WRSR) was employed for two-layer multi-objective optimization to acquire the optimal system performance of diverse working fluids under the optimal three pinch-point temperature difference ratio and to quantitatively categorize the working fluids. The results indicate that the comprehensive performance of the SRPH-DPORC system is superior. The optimal performance corresponds to a temperature difference ratio of 1:4:15. The performance of the working fluid R365mfc is more favorable, and the economic performance of the zeotropic mixtures containing R365mfc and R601a is better. The working fluid R365mfc or the zeotropic mixture containing R365mfc is preferable under the weighting factor scheme emphasizing thermal performance and economic performance. Under the weighted factor scheme that emphasizes environmental performance and sustainable development performance, the working fluids R601a and R1233zd are more suitable. The working fluid c2butene is not appropriate for operation in the SRPH-DPORC systems.