Comparative exergy-based performance analyses and optimisation of combined power cycles

Abstract

The value of energy resources has grown significantly these days, making their proper and intelligent utilisation crucial. Improvements are being made to both new and existing systems to satisfy the rising energy demands and effective use of energy. Supercritical and organic Rankine power cycles (ORCs) for waste heat recovery are commonly used to create more effective and ecologically friendly systems. The article in this context analyses the effects of temperature and pressure ratios on the various objective functions of four different systems (1-Brayton, 2-Brayton-sCO2, 3-Brayton-sN2, and 4-Brayton-ORC). As a result, this study will find the optimum solutions and systems for one or more usage purposes. While System 1 can be chosen as optimum in terms of ECOP and ηII, System 4 can be chosen as the best system in terms of wnet and ηth. All systems have certain limitations relative to one another when operating at their optimum under specific parameters.