A comprehensive review of exergy analysis in sustainable engineering systems: Fundamentals, methods, applications, and challenges

Exergy analysis is a thermodynamic framework for evaluating the performance and irreversibilities of engineering systems by quantifying energy degradation and efficiency losses. This review systematically examines the fundamental principles of exergy theory, its governing equations, and its implementation across energy, thermal, industrial, and environmental systems. The paper analyzes key applications of exergy-based assessment in diverse technologies, including energy conversion systems and heat transfer-dominated processes. By synthesizing existing literature, the review identifies methodological variations, differences in reference state selection, and inconsistencies in performance indicator definitions. Current challenges related to data uncertainty, modeling assumptions, and practical implementation are discussed. The study concludes by outlining research gaps and future directions to improve the consistency and integration of exergy analysis in sustainable engineering applications.