Climate-Responsive Integration of Phase Change Materials in Building Envelopes: A Systematic Review and Libya-Focused Roadmap for Hot-Arid and Mediterranean Climates

Abstract

Buildings in hot-arid and Mediterranean regions experience substantial cooling loads, pronounced daily temperature swings, and growing exposure to climate-related heat stress. Phase change materials (PCMs) can moderate these effects through latent thermal energy storage, yet their performance depends on climate, phase-transition temperature, integration position, building operation, and methodological assumptions. This systematic review synthesizes a deduplicated evidence base of 90 unique studies published primarily during 2020–2025. Bibliographic, climatic, material, envelope, methodological, and performance variables were harmonized and analyzed using a PRISMA-aligned workflow. Studies published in 2024–2025 represented 58.9% of the evidence base. Hot-arid/desert and Mediterranean climates accounted for 23.3% and 21.1%, respectively. Organic PCMs dominated (64.4%), walls or façades were investigated in 73.3% of studies, and numerical or simulation-based methods represented 58.9%. Quantitative energy-saving values were reported in 37.8% of studies, with substantial heterogeneity in baselines and outcome definitions. The review proposes a climate-responsive integration framework and a Libya-focused roadmap emphasizing multi-city field validation, locally appropriate transition-temperature selection, aging and cycling assessment, techno-economic and life-cycle evaluation, and open benchmark datasets. Available evidence supports targeted Libyan pilot studies but not direct transfer of generalized performance claims.