Exploring energy-efficient building solutions in hot regions: A study on bio-phase change materials and cool roof coatings

Creating low-energy buildings in arid, hot desert climates like Kuwait poses significant challenges. This research examines the potential of Bio-PCMs and cool roof coatings as energy-saving methods in three hot climate locations, using both experimental and computational approaches. Two identical portable cabins were meticulously constructed, and their thermal properties were analysed under two different cooling conditions. These cabins offer a unique testing ground for various energy-saving techniques, as their thermal similarity has been experimentally confirmed. A six-zone model was developed in TRNSYS software to study Bio-PCM integrated walls. The findings for the desert climate of Kuwait and subtropical climate of Rockhampton, Australia, demonstrated the best performance with autoclaved aerated concrete block walls, achieving energy performance indices of 761.7 and 496.3 kWh/m²/year, respectively. Bio-PCMs integration in three positions within walls and roof were examined, which were yielded energy savings of 22%, 23%, and 53% in Kuwait, Australia, and India, respectively, while experimental results on two cool roof methods, cool roof paint and aluminium foil roof, indicated that energy savings proved to be negligible. Incorporating insulation materials via sandwich panels in buildings can substantially enhance energy efficiency in Kuwait and Australia, with observed reductions of 35.7% and 43.8% compared to autoclaved aerated concrete blocks from simulation results. However, in tropical climate of Kodaikanal, India, energy consumption were increased dramatically by 126.2% when sandwich panels were used. This study offers valuable insights into optimal wall materials and energy-saving strategies, such as cool roof methods, insulation and Bio-PCM, for use in various hot climates.