Experimental energetic evaluation of changeable thermal inertia PCM containing walls

The insertion of Phase Change Materials (PCM) inside light dry assembled building envelopes seems to be the right way to solve overheating problems usually caused by the low thermal inertia of such walls. An experimental campaign was held during the summer of 2004 at the Renewable Energies Outdoor Laboratory of the Polytechnic University of Marche (Ancona, Italy), where three experimental boxes were built: two of them were built with the south-facing walls containing PCM characterized by different stratifications, whereas the third box was built using a light multi-layered south facing wall
without the insertion of PCM (hereon referred to as reference box). The use of the PCM provided three main positive results when compared to the reference box:
- lowering of the radiant surface wall temperatures, even if not provided with a thick insulation layer;
- strong reduction of incoming heat flux in the presence of a PCM layer, whose peaks are halved compared to the reference wall;
- shift in time of the highest incoming heat flux value occurrence which, for south-facing PCM containing walls, moves to a number of hours later than the reference boxs wall.