Location of the phase-change material layer on thermal performance of light-weight walls

Light-weight materials are commonly used in high-rise buildings to reduce the building weight, but their thermal inertia will increase the fluctuation of air-conditioning and heating load and reduce indoor thermal comfort. Phase-change material (PCM) is employed to improve the thermal behavior by latent thermal storage, but its location has the obvious impact on the thermal behavior improvement of the light-weight wall. According to this condition, by taking the common multi-layer wall as a reference, three walls were built with different locations of the PCM layer, including locating the PCM layer in inner side, locating the PCM layer in outer side and distributing PCM uniformly into foamed concrete. The dynamic heat transfer model with the phase change was built and verified by an experiment. Numerical results showed locating the PCM layer in inner side is the best in three locations and followed by distributing PCM uniformly into foamed concrete, while locating the PCM layer in outer side is the worst in spite of the high liquid fraction variation. Locating the PCM layer in the inner side can lower the attenuation factor by 101.25% and 33.87%, increase the delay time by 40.00% and 17.14%, reduced by the peak heat flow by 47.69% and 17.28%, compared to locating the PCM layer in the outer side and distributing PCM into foamed concrete uniformly.