Sustainable Roof Design Using PCM Under Hot Climate Conditions

Hot climate areas worldwide are observing severe heat waves every year due to global warming and greenhouse gas emissions. The exploration of sustainable and passive solutions is a must in order to reduce the extreme impact of these heat waves and their impact on the electricity grid operation. This work proposes the use of a phase change materials (PCM) layer on the outside surface of a roof to passively reduce the indoor room temperature. Parafin wax and paraffin oil were mixed at different ratios and fabricated to panels with different thicknesses. The proposed solution is tested in a room located in Cairo, Egypt by adding different layer thicknesses of PW1 (4 cm) and PW2 (6 cm). Results exhibits that the using of PW1 and PW2 layers of PCMreduces the indoor temperature by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$11-11.5^{\circ} \mathrm{C}$</tex> compared to non-AC conditions. Also, PW1 reduces the required air conditioner size from 5 HP to 3 HP, leading to a 50% reduction in electricity consumption. PW1 is more favourable over PW2 since it achieves similar thermal improvement,lowering peak temperatures by 11.5° C while having a thinner layer.