Simultaneous use of renewable energies and phase change materials to reduce energy consumption in Saudi buildings: Examine the photovoltaic cells

Abstract

According to the Net Zero long-term plan, about 95% of the building's CO2 emissions should be declined by 2050 compared to 2020. In this study, focusing on “energy efficiency” and “renewables”- key pillars of the Net Zero plan-two techniques of adding photovoltaic cells (PVs) along with the loading of phase change material (PCM) to Saudi Arabian buildings were studied. In the first pillar, the installation of PV cells on all the horizontal/vertical envelopes was checked and it was found that in the same area, the electricity production on the roof is 136% more than the south-oriented vertical envelope and 1126% more than the north one. On the other hand, PVs on the roof reduce the cooling load by 5.8%, increase the heating load by 2.5%, and finally reduce the annual energy demand by 4.6% as a side effect. For the second pillar, PCM was installed in vertical/horizontal envelopes. As the thickness of PCM increases, annual energy consumption decreases, but at a lower rate. When the thickness of PCM reaches 15 cm, it is expected that it will have an energy savings of 9855 kWh/year, but the calculations exhibit a value of 4701 kWh, which demonstrates the fall in PCM effectiveness with thickness rise. The effect of PCM installation location had a very important effect. To reduce the cooling load, PCM should be installed in the outermost layer, and vice versa for the heating load, it should be installed in the innermost layer. When the annual analysis is prioritized, installing PCM in the outermost layer can perform better than the innermost layer up to 14.6%.