Adjustment of thermal behavior by changing the shape of PCM inclusions in concrete blocks

Most installed phase change materials in real applications are typically spherical microencapsulated paraffin. However, salt hydrates can be a cheap alternative when combined with a suitable macroencapsulation. Such macroencapsulation enables the installation of different shapes and positions within the building material. Therefore, an experiment setup consisting of a wooden box equipped with infrared radiators and a cooler was used to investigate cuboid, cylindrical, plate-shaped, and spherical phase-change packages. All water vapor impermeable packages filled with salt hydrate were positioned within a standard concrete block. As a result, it can be seen that changing the design of a PCM package enables the opportunity to adjust the thermal behavior without changing the mass of the PCM. For a high heat transfer, a set up position of a large number of thin packages with a large heat transfer surface was found to be the best design. Using a thermal shading effect and an even distribution of the PCM within concrete block ensures a slow increase in the temperature of the block and thus a lower heat flow into the inner rooms.