Utilization of Waste Heat in Closed Brayton Cycle: A Thermodynamic Analysis with Various Working Fluids

Authors : Gamze Soytürk

Pages : 405-417

Doi:10.34248/bsengineering.1592949

View : 45 | Download : 56

Publication Date : 2025-03-15

Article Type : Research Paper

Abstract :This research investigates the thermodynamic performance of a power generation system employing five working fluids: helium, carbondioxide, nitrogen, argon, and neon. Key parameters like net power generation, exergy destruction, energy and exergy efficiencies, and mass flow rates were evaluated under varying operational conditions. The analysis revealed that carbondioxide consistently outperformed other fluids, achieving the highest net power generation of 450 kW at lower compressor inlet temperatures, and maintaining the lowest exergy destruction of approximately 500 kW. Additionally, carbondioxide exhibited superior energy and exergy efficiencies, with values reaching 31% and 45%, respectively. Nitrogen and argon demonstrated moderate performance, with nitrogen achieving a stable net power generation of around 250 kW and an exergy destruction of approximately 700 kW. Both fluids-maintained energy efficiencies near 17% and exergy efficiencies of approximately 25%, making them suitable for balanced thermodynamic systems. In contrast, neon and helium showed limited performance, with neon recording the lowest net power generation of 170 kW and a relatively high exergy destruction of 770 kW. Helium similarly exhibited reduced efficiencies, with energy efficiency dropping to 13% and exergy efficiency to 19% under varying conditions. Mass flow rate analysis indicated argon required the highest flow, at approximately 9.5 kg/s, while helium maintained the lowest at 1 kg/s, reflecting their respective densities and energy transport capacities. These findings underline the critical role of working fluid selection, with carbondioxide emerging as the optimal choice for systems prioritizing high efficiency and minimal energy losses. The study provides a comprehensive framework for enhancing thermodynamic performance in power generation applications.
Keywords : Waste heat recovery, Power generation systems, Working fluids, Thermodynamic analysis