Enhanced Thermal Performance of Roofing Materials by Integrating Phase Change Materials to Reduce Energy Consumption in Buildings

Abstract

This work focused on characterizing and improving the thermal behavior of metal sheet roofing. To decrease the heat transfer from the roof into a building, we investigated the efficiency of four types of phase change materials, with different melting points: PCM І, PCM II, PCM III and PCM IV, when used in conjunction with a sheet metal roof. The exterior metal roofing surface temperature was held constant at 50°C, 60°C, 70°C and 80°C, using a thermal source (halogen lights) for 360 min to investigate and compare the thermal performance of the metal sheet roofing with and without phase change materials for each condition. The thermal behaviors of the phase change materials were analyzed by differential scanning calorimeter (DSC). The results showed the melting points of PCM І, PCM II, PCM III and PCM IV were around 45°C, 50°C, 55°C and 59°C, respectively. The integration of PCM IV into the metal roofing sheet increased the thermal performance by reducing the room temperature up to 2.8%, 1.4%, 1.0% and 0.7% when compared with the normal metal roof sheet, at the controlled temperatures of 50°C, 60°C, 70°C and 80°C, respectively. The thermal absorption of the phase change materials also caused a time delay in the model room reaching a steady temperature. The integration of phase change materials with metal roofing sheets resulted in better thermal performance and conservation of electrical energy by reducing the demand for cooling.