Numerical Simulation of a PCM Shutter for Buildings Space Heating During the Winter

The integration of Phase Change Materials (PCMs) into the building envelope provides a higher thermal inertia that, combined with the thermal insulation effect, can reduce the energy consumption. Using a 2-dimensional simulation model based on the enthalpy formulation, a latent heat storage system has been numerically designed and parametrically optimized to take advantage of solar thermal energy for buildings space heating during the winter in Coimbra, Portugal. The main purpose of this study is to show the potential of incorporating PCMs in structural cells of shading elements associated to southward facade windows. In view of the low thermal diffusivity of the Phase Change Material (PCM) chosen, the distance between metal fins is directly proportional to the energy storage/release capacity of the system. The results of the parametric study also show that solar radiation flux has a strong effect on the melting/charging process. On the other hand, the indoor temperature and the indoor heat convection transfer rate, during the night, play an important role in PCM solidification/discharging process. In conclusion, an optimal thermal storage system – PCM shutter – can be designed for any given location and characteristic climatic data during the winter. The optimum depends strongly on the thermophysical properties of the PCM and on the internal boundary conditions considered.