Binary-objective optimization of latest low-GWP alternatives to R245fa for organic Rankine cycle application

摘要

Organic Rankine cycle (ORC) enables to harness waste heat resource to generate electrical power. R245fa is assumed as an appropriate working fluid for low-temperature waste heat recovery. However, strict regulations of CO2 emissions stimulate scientists to search for potential alternatives to R245fa. This paper presents a comparative analysis of various latest low-GWP refrigerants for ORC application. An energetic-economic-environmental evaluation model is established and further integrated into the non-sorted genetic algorithm (NSGA-II) for multi-objective optimization (MOO). A classic decision-making method is employed to screen out the optimal refrigerant for current study. Apart from that, the whole-year ambient conditions in Sydney are taken into consideration to screen refrigerants. Comparing the cycle thermal efficiency, R1224yd(Z) leads to 3.3% higher than R245fa. Comparing the economic cost, it saves 10.4% more than R245fa. Comparing the whole year's performance, R1224yd(Z) exhibits 11.2% higher cycle thermal efficiency than R245fa while R1234ze(Z) saves 9.85% more economic cost than R245fa. R1224yd(Z) is considered as the optimal working fluid for current ORC system. R1224yd(Z) leads to 16% higher LECTs than R245fa. Comparing the maximum LECTs, R1224yd(Z), R1234ze(Z) and R1233zd(E) is 16%, 9.2% and 13.5% higher than R245fa, respectively. (C) 2020 Elsevier Ltd. All rights reserved.