Optimising the integration of phase change materials in construction in South Mediterranean regions: A case study from Algiers, Algeria

This study investigates the integration of phase change materials (PCMs) into conventional building envelopes in Mediterranean climates, with a focus on Algiers, Algeria a region characterised by hight diurnal temperature fluctuations and peak summer temperatures reaching 35 °C. The paraffin-based PCM RT35-HC (melting point ≈35 °C) was embedded at the core of wall assemblies composed of four locally prevalent construction materials: fired brick, aerated concrete, stabilised earth concrete, and slag concrete. Using COMSOL Multiphysics®, a two-dimensional transient heat transfer model was developed to evaluate the thermal performance of each wall configuration under representative climatic conditions. Simulations assessed the influence of material type and PCM placement on indoor thermal stability, particularly on time-lag, temperature attenuation, and heat flux reduction. Results indicate that aerated concrete combined with RT35-HC PCM provides the most effective thermal buffering, significantly delaying heat transfer and maintaining lower interior surface temperatures throughout the diurnal cycle. These findings support using PCM-enhanced lightweight materials to improve energy efficiency and thermal comfort in South Mediterranean regions.