Effects of Phase Change Materials on heat flows through double skin facades

The potential of exemplary organic and inorganic Phase Change Materials (PCMs) as façade integrated storage is tested. The impact of two PCMs on heat flows is assessed in comparison with water and concrete. The simulation-study employs a transient Modelica simulation model of a test cell featuring the Solar Energy Balanced Façade (SEBF). It is shown that, when compared to water, PCMs of identical volume change the seasonal energy balance in winter and summer by only ± 4%. Other than water, the PCMs maintain this effect even if the storage volume decreases. Due to spatial constraints, this can support the integration of thermal storage in façade design considerably. Preliminary results indicate that designing thermal storage in façades with PCMs must not only consider the latent heat storage capacity, but also take into account the combined effects of latent heat capacity, melting point, conductivity, and dead load. The application of PCMs promises to foster the integration of the technology of SEBF into façades, but the necessary deliberate selection of, and design with, PCMs requires further research.