Thermal insulation of walls and roofs by PCM: modeling and experimental validation

Kamal A. R. Ismail, J. N. Castro, Fatima A. M. Lino

In hot and tropical countries external walls and roofs receive solar radiation absorbing part of it and transmitting a substantial part to the internal ambient provoking thermal discomfort. In cold climate heat is usually lost to the external ambient and again causing thermal discomfort. In both cases the thermal energy load is increased. For these reasons many studies were dedicated to investigate techniques for improving the thermal performance of walls and roofs. One of the most viable techniques is the use of PCM as thermal insulation filler that increases the thermal inertia of the component at relatively low cost and without substantial increase of weight. The formulation of the problem of the PCM composite wall is based on one dimensional pure conduction model for the PCM and the walls. The numerical solution involves moving grid for the PCM. The computational grid was optimized to eliminate grid size effects. The model was extended to treat the roof problem. The numerical predictions were compared with experimental results and reasonably good agreement was found.  Additional numerical and experimental results were presented and discussed.