The building sector accounts for a relevant portion of the overall energy consumption and CO2 emissions. The type of construction materials used in the buildings as well as the characteristics of the envelope affect their energy consumption. The choice of appropriate building materials is a crucial challenge widely discussed in the context of the bioclimatic architecture concept. The implementation of phase change materials (PCMs) into the building envelope is among the investigated solutions to make the building sector more sustainable. In this paper, cement mortar integrated with solid/solid PlusIce X25 commercial PCM was characterized and tested. The main feature of the proposed composite is the use of the solid/solid phase change, which avoids typical PCMs' issues due to the leakage occurring when the material becomes liquid. The properties of the PCM material itself were investigated by measuring the latent heat and the phase change temperature through differential scanning calorimetry (DSC). Furthermore, in order to evaluate the performance of the realized samples, an experimental setup was designed and built. The main feature of the experimental setup is the possibility to test two different cement mortar bricks subjected contemporary to the same testing conditions. Experimental results confirmed the advantages of the PCM-loaded plaster. Thermal performances of the PCM were further compared to those ones of two specimens of cement mortar incorporating rubber and cork with the same experimental conditions. Experimental results were used to validate and calibrate a finite element model, implemented in COMSOL Multiphysics 5.6. Parametric simulations to investigate the effect of the PCM mass fraction were carried out. The results showed remarkable thermal performance improvements in terms of peak temperatures reduction with mass fraction of 25-50%. Furthermore, different placements of the PCM in the wall of a building were simulated and discussed.

In the present work, the experimental and theoretical analysis of hybrid cement mortar embedding microencapsulated PCMs is reported. Different samples with variable PCM loading, up to 15 wt.%, were prepared and experimentally tested by means of a properly designed and realized setup, able to compare the dynamic thermal behaviour of two sample contemporary. The results demonstrated that the mixed PCM samples are characterized by higher overall thermal capacity, which allows limiting the temperature fluctuation if compared to standard pure cement mortar sample. Furthermore, a numerical model was implemented in COMSOL Multiphysics and satisfactorily validated by means of the experimental results. The validated model will be then employed to simulate full-scale building configurations making use of the proposed hybrid cement mortar - PCM.