Novel indicators to evaluate PCM performance under different ventilation strategies by considering the impact of climate change

Due to climate change, the cooling energy demand in the building sector is projected to increase significantly. According to International Energy Agency, for a sustainable future, energy-efficient technology should be implemented in buildings. The potential of Phase change materials (PCM) for reducing building energy consumption has been widely acknowledged by researchers. However, the selection of appropriate PCM and its latent heat exploitation is crucial when PCM is integrated into the building envelope. This research evaluates the implementation of PCM for building cooling energy savings (CES) with climate change in thirty-nine cities located in 13 different zones of the future Koppen-Geiger climate map. Novel performance indicators, energy charging, and discharging coefficients are presented, to evaluate the PCM performance based on the exact latent heat exploitation. A range of PCMs (PCM 18–32) were assessed by coupling PCM with free night ventilation and changeover ventilation using the hybrid downscaled weather files for 2095. The results showed that the optimum PCM varied from PCM27 to PCM30 resulting in substantial CES (1214 kWh-7240 kWh) in all zones except Cfb, Dfa, and Dfb under the indoor HVAC controlled conditions. In natural ventilation conditions, combining PCM with free night ventilation increased CES up to 2490 kWh compared to night ventilation alone, while combining PCM with changeover ventilation, reduced energy consumption by up to 2772 kWh compared to changeover ventilation alone. Overall, free night ventilation with PCM improved the CES by up to a maximum of 35% while changeover ventilation in combination with PCM further increased the CES by up to 96% and appeared to be the best strategy for maximizing the CES in all climate zones.