Graphite-enhanced microencapsulated phase change material - geopolymer composites for passive cooling: Experimental, numerical and life cycle assessment under climate change
Construction and Building Materials, cilt.538, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 538
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.conbuildmat.2026.147130
- Dergi Adı: Construction and Building Materials
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Anahtar Kelimeler: Energy storage, Geopolymer, Graphite, Life-cycle assessment (LCA), Passive cooling, Phase change material (PCM), Wall configurations
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
Rising cooling demand under climate change creates a need for low-carbon building envelope materials capable of passive thermal regulation. This study investigates the development and multi-scale performance of geopolymer composites incorporating microencapsulated phase change materials (μPCM) and graphite as multifunctional additives for building envelope applications. The composites were synthesized through alkali activation of a fly ash–ground granulated blast furnace slag binder and characterized in terms of workability, density, mechanical strength, thermal conductivity, and latent heat capacity. Incorporation of μPCM increased latent heat storage capacity but reduced workability and mechanical strength; however, all mixtures yielded 28-day compressive strengths above 22.9 MPa, indicating promising strength levels for structural applications. The reduction in thermal conductivity caused by μPCM incorporation was partially compensated by graphite addition, resulting in up to a 30% increase compared with non-graphite composites. To evaluate performance, transient simulations were conducted for multi-layer exterior wall configurations using experimentally measured thermophysical properties under dynamic climatic conditions. The results indicate that μPCM content, layer placement, cooling set-point temperature, and wall orientation strongly influence cooling energy performance. Locating μPCM-rich layers near the interior surface improved thermal regulation by enhancing nighttime re-solidification and peak-load mitigation, outperforming uniform PCM distributions even at lower overall PCM contents. Life-cycle assessment and cost analysis over a 30-year service life revealed global warming potential reductions of up to 303 kg·CO2-eq/m² and cost savings of up to 32 USD/m². These findings demonstrate that graphite-enhanced μPCM-geopolymer composites provide a promising low-carbon strategy for enhancing thermal storage and climate resilience in building materials.