Energy-efficient concrete roofs for buildings: Integrating macroencapsulated nano-enhanced PCMs for hot climate adaptation
Direct sunlight on concrete roofs raises interior heat flow and cooling demands. Latent heat storage with phase change materials (PCMs) offers passive cooling, but nanomaterials are needed to improve their low thermal conductivity. In this study, a two-way hollow concrete roof (HCR) integrated with...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-02-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25000048 |
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| Summary: | Direct sunlight on concrete roofs raises interior heat flow and cooling demands. Latent heat storage with phase change materials (PCMs) offers passive cooling, but nanomaterials are needed to improve their low thermal conductivity. In this study, a two-way hollow concrete roof (HCR) integrated with macroencapsulated nano-enhanced PCM (NePCM) is developed for passive cooling and tested under ambient conditions. Characterization of selected organic PCM (OM35) is conducted individually and in combination with 2 % and 4 % mass fractions of multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP). Following unit cell approach, a conventional concrete roof (CCR) without PCM and three HCR specimens are cast: OM35–SU, 2%GNP–NePCM, and 4%GNP–NePCM. Thermal performance of the four specimens is assessed by analyzing temperature variations, heat flow, thermal load, decrement factor, and time lag. It is observed that thermal conductivity enhances 36.4 % and 45.5 % in 2 % and 4%GNP–NePCMs over OM35. During sunny hours, OM35–SU, 2 %, and 4%GNP–NePCMs reduce indoor surface temperatures by an average of 8.1, 8.7, and 9.6 °C, respectively. Cooling loads in 2 % and 4 % GNP–NePCMs are 68 % lower than CCR. Further, 2 % and 4 % GNP–NePCMs have 33 % and 36 % less mean time lag than OM35–SU. The findings offer valuable insights into the macroencapsulation of NePCM in roof slabs, enabling effective thermal energy management for indoor environments in hot climates. |
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| ISSN: | 2214-157X |