Numerical investigation and optimization of macro-encapsulated phase change material capsules in building roof slab

Globally, rising temperatures, together with the growing population, urbanization, and improved living standards, are driving a sharp increase in energy demand in the building sector. Space cooling and heating are the major areas of energy consumption. The building's roof slab thermal performance significantly impacts the heating and cooling requirements. Various studies investigated incorporating phase change material (PCM) to enhance the thermal characteristics of roof slabs. In this paper, the effective utilization of macro-encapsulated PCM in reinforced cement concrete (RCC) roof slab is investigated numerically. This research explored the effect of shape, heat transfer area, and thermal shading with the same amount of PCM on the impact of the reduction of inner roof temperature. Validation of the model with the experimental results is done for the current study. A total of 12 different cases, along with a reference case, were examined. In addition, the structural performance of the RCC conventional slab and slab with PCM capsules is also examined. Findings of the study include: cuboid with less thickness was found as the best shape. The increment in heat transfer area leads to better thermal performance while also providing the best case, with 3.2 °C and 1.2 °C peak and average temperature reduction. The thermal shading phenomenon was found to have positive results for the winter solstice. The deflection of all the slab cases was observed to be within the limits.