LAUSR

Abstract Phase change materials (PCM) occupy an important position in modern technologies. The use of PCMs in parts of a building structure is a new trend in energy efficient construction. In this study, a building block model with PCM inserts was considered. The influence of the position of the insert and the melting point of the material on the thermal performance of the block during unsteady heating and cooling is analyzed. A numerical model that describes the unsteady process of phase transitions taking into account natural convection, formulated in dimensionless temperature, stream function, vorticity is used. It is shown that, depending on the position of the phase change material, the temperature of the outer surface can vary within several degrees and on the inner surface within one degree. Moreover, it is demonstrated that at higher melting temperatures the material can give a positive result only during hot days. Namely, if the melting point of the material is close to the maximum ambient temperature or higher, then the effect will not be observed, since the material will not start to melt.