Evaluation and optimization of PCM-integrated walls: Energy, exergy, environmental, and economic perspectives

Phase Change Materials (PCM) is a promising solution for thermal energy storage, offering significant potential to enhance the efficiency of renewable energy systems, reduce energy consumption, and support sustainable energy practices in nearly zero-energy buildings (NZEB). While extensive research has examined the energy performance of PCM-integrated walls, a comprehensive evaluation that simultaneously considers energy efficiency, exergy performance, carbon footprint, and economic feasibility remains limited. This review addresses this gap by assessing the current status and applicability of the Energy, Exergy, Environmental, and Economic (4E) analysis for PCM-integrated walls and identifying key evaluation metrics and methodologies. Additionally, multi-objective optimization is explored to determine the optimal configuration of PCM-integrated walls, addressing trade-offs among the 4E objectives. Furthermore, the review emphasizes the growing role of artificial intelligence (AI) in enhancing multi-objective optimization within the 4E framework. Findings indicate that PCM-integrated walls can reduce annual energy use by 13–50 %, enhance exergy efficiency by up to 50 %, and lower total environmental impact by roughly 12–34 %. Payback periods are generally greater than 5 years. Notably, the combination of smart control systems with PCM-integrated walls can further enhance exergy performance by an additional 5–50 %. This review serves as a valuable reference for advancing the application of PCM in sustainable building wall design, thus contributing to the broader adoption of renewable energy strategies.