Heat and cold storage systems of buildings are based on different concepts of heat transfer. In thermal hybrid storage systems, the phase change material (PCM) is macroencapsulated in PCM objects which are positioned in the storage tank and around which the heat transfer fluid flows. The experimental investigations are dedicated to the loading and unloading properties of the PCMs macroencapsulated in spheres. It is shown that the specific heat transfer performance of a hybrid storage tank is directly dependent on the size of the spheres as well as on the specific thermal conductivity of the PCM.