Transient Thermal Optimization of Hollow Block for Roof Slab using PCM Integration and other Efficient Infill Materials Under Real Climatic Conditions

Abstract

This study focuses on the thermal optimization of hollow concrete blocks by incorporating different infill materials to enhance their thermal performance. A numerical model was developed to analyse transient heat transfer through hollow blocks under varying thermal conditions. The study considers different infill materials, including Phase Change Material (PCM), Expanded Polystyrene (EPS), and foamcrete. The geometry of the hollow block was modelled based on standard dimensions, and material properties were adopted from established literature. The temperature boundary conditions were established utilizing hourly climatic data for Dammam during peak summer conditions, sourced from Time and Date and employed in the transient thermal analysis. The validation of the slab panel model was conducted by comparing the numerical results with available published data to ensure accuracy and reliability. Thermal performance was evaluated using parameters such as temperature variation and heat flux.

Introduction

The text discusses improving the thermal performance of hollow block slabs used in construction, especially in hot climates where they allow significant heat transfer and increase cooling demands. To enhance insulation, different infill materials—Expanded Polystyrene (EPS), foamcrete, and Phase Change Materials (PCM)—are evaluated and compared against hollow blocks without infill.

The study aims to analyze how these materials affect temperature distribution and heat flux, particularly under peak summer conditions in Dammam, Saudi Arabia, and to assess the effect of filling different cavity configurations during day and night conditions. The analysis is carried out using ANSYS Workbench through transient thermal simulations.

A hollow block with six cavities is modeled, and each configuration (no infill, EPS, foamcrete, PCM) is tested using real hourly temperature data. Material properties such as thermal conductivity, density, and heat capacity are considered in the simulation.

Key results:

• Without infill: highest temperature (~38°C) and moderate heat flux
• PCM infill: best performance with lowest temperature (~30°C) and very low heat flux
• EPS infill: good insulation with ~30°C temperature but higher heat flux
• Foamcrete infill: moderate improvement (~35°C temperature)

Conclusion

The research shows that infill materials make hollow masonry bricks work much better in terms of heat transfer when the temperature is at its highest. PCM infill lowered the peak temperature by about 21.13% and the heat flux by 99.64% compared to the unfilled brick. This is because it can store latent heat, which makes it the most efficient. EPS infill also lowered the temperature by about 20.85%, but it raised the heat flux by about 67.30%. Foamcrete infill lowered the temperature by about 6.70% and the heat flux by 98.36%.The results also show that the type of infill material and how well it stores heat have a big effect on how the brick reacts to heat. PCM effectively slows down the transfer of heat by taking in and releasing latent heat. This makes the temperature inside more stable and less likely to change. The decrement factor analysis shows that PCM does a better job of blocking heat waves than other materials. These results show how important it is to choose the right infill materials for energy-efficient building design, especially in hot weather. In general, PCM is the best material for filling in gaps in hollow masonry systems because it improves thermal comfort and reduces heat gain.

References

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Copyright

Copyright © 2026 Nafeesa Nasrin V K, Sarah Anil . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.