Despite their very promising building energy storage capabilities, PCM are still in the investigating phase before a large potential deployment. This is due to several challenges [1] such as high storage capacity and efficient heat extraction [2,3,4]. If the storage capcity can be adapted by implementing appropriate quantity of PCM, the heat extraction efficiency is more delicate and difficult to optimize. It depends on the conductivity of the PCM and on the heat flow between the PCM surface and the indoor air which can be enhanced by ventilating the PCM surface.