Breaking new ground: A first-of-its-kind critical analysis of review articles on phase change materials for building applications

The integration of phase change materials (PCMs) into building envelopes presents an effective approach to improving energy efficiency through enhanced heat storage. By improving energy efficiency and reducing reliance on fossil fuels, PCMs hold significant potential to mitigate the environmental impact of building operations. Despite a wealth of review literature on PCMs, a comprehensive and critical synthesis that consolidates insights, identifies research gaps, and provides a structured perspective remains lacking. Therefore, this study presents a novel and extensive critical review of all available review articles on PCMs, from the first in 1983 to the present, offering a state-of-the-art synthesis that unifies existing knowledge and guides future research and applications. A critical review of 271 review articles is conducted for the first time, providing in-depth insights from the earliest review to the present. While review papers often compile surface-level facts and trends, they may oversimplify or fragment the broader understanding of literature. Therefore, critically evaluating these articles is essential to uncover deeper insights, distinguish substantive findings from superficial observations, and establish consensus on key challenges and potential solutions in the field. This review briefly discusses the categorization of PCMs and their encapsulation techniques and compiles all the commercially available PCMs in tabular form with details of their thermophysical properties. It goes beyond existing studies by addressing a notable omission—many reviews on commercial PCMs do not include detailed information about their manufacturers. To bridge this gap, we have systematically gathered and presented comprehensive manufacturer data, along with direct links to their websites. Our compilation encompasses nearly all commercially available PCMs explored in the literature to date, ensuring that researchers and industry professionals have easy access to verified and exhaustive information. This makes our review a uniquely valuable and practical resource for advancing research and industrial applications. The review also examines PCMs with different natural ventilation strategies, highlighting their potential to enhance indoor thermal comfort and energy efficiency. Furthermore, the economic viability and environmental implications of PCM applications are critically evaluated, accompanied by a detailed life cycle assessment to understand the impact of materials from production to operation and demolition. The application of PCMs in buildings is analyzed in sufficient detail, and challenges and limitations associated with PCM incorporation are thoroughly covered. Extensive opportunities for future research are identified, serving as a roadmap for advancing PCM technology while uncovering unexplored areas and addressing critical gaps in the existing literature. Finally, the review concludes by thoroughly synthesizing all key concepts discussed in the paper through detailed bullet points, each accompanied by comprehensive recommendations, offering an in-depth framework to guide future studies and advance PCM research and applications.