Energy-Saving potential of radiative cooling and phase change materials in hot Climates: A numerical study

The combination of radiative cooling and phase change technology has significant potential for reducing energy consumption in buildings. However, most current studies primarily focus on cooling load analysis, with limited attention given to the total annual energy consumption, leaving room for further optimization. To address this gap, this study numerically investigates the energy-saving potential of radiative cooling-phase change material (RC-PCM) co-applied to building envelopes in hot climates. Three models of OM, PCM, and RC-PCM were developed using Energyplus and validated based on experimental data, with a maximum deviation of less than 7 %. Based on the validated models, a comparative analysis of energy consumption was conducted for the climates of Ganzhou and Guangzhou, with key parameters such as melting temperature, phase change radius, thickness, and latent heat of PCM optimized. The results indicate total annual energy savings of 31 kWh & sdot;m- 2 in Ganzhou and 38.9 kWh & sdot;m- 2 in Guangzhou, while annual heating energy savings were -6.6 kWh & sdot;m- 2 and -2.2 kWh & sdot;m- 2, respectively. The optimal melting temperature for minimizing total annual energy consumption was 20 degrees C in Ganzhou and 22 degrees C in Guangzhou, while the optimal PCM thickness was 15 mm in Ganzhou and 20 mm in Guangzhou. The differing results were attributed to Ganzhou's classification as a hot summer, cold winter area, compared to Guangzhou's hot summer, warm winter climate. These findings demonstrate the significant energysaving potential of RC-PCM and provide valuable guidelines for the optimal design of building envelopes with RC-PCM in hot climates.