Multi-objective decision framework for comprehensive assessment of organic Rankine cycle system

Abstract

A multiobjective decision framework, which is developed to determine the optimal operational parameters and choose the best working fluids for the organic Rankine cycle taking thermodynamics, economy, and environment into consideration, is proposed. Net output work, electricity production cost (EPC), and equivalent carbon emission (ECE) are adopted as the thermodynamic, economic, or environmental indicators in the decision framework. Then, a sensitivity analysis is conducted to investigate the effect of criteria weights on working fluid selection and their priority variations. Finally, the decision results obtained from the Technique for Order by Similarity to Ideal Solution are compared with those obtained by another two kinds of decision making methods, namely, Multi-Factor Evaluation and Vector-Based Ranking method. Butane, R245fa, R1233zd(E), R245ca, and R123 are chosen as the working fluids. The result shows that R1233zd(E) is recognized as the most appropriate working fluid under the above three decision methods in this work. The corresponding net output work, EPC, and ECE are 7.76 kW, 6.690 × 10−2 $/kWh, and 2.075 × 10−2 kg CO2eq/kWh, respectively.