br Numerical simulation models The

Numerical simulation models The simulation model is based on a three-dimensional case which was transformed into cylindrical coordinates. The TPS KU60019 manufacturer was clamped in the center of two identical material samples. During short calculation periods, when the heat has not reached the boundary of the sample, the setup can be treated as a cylindrical case, see Figure 1. Table 1 shows the thermal diffusivity, a (m2/s), and penetration depth, d (m), where half the possible temperature change has occurred after 40s. The thermal properties were based on tabulated data. The geometry of the numerical model has to be larger than the penetration depth after 40s to ensure the heat has not reached the boundaries of the samples.
Analytical solutions The analytical solutions for the heat supply over a part of a circular surface have been developed previously (Carslaw and Jaeger, 1959). To validate the results of the numerical model in Section 3.1 the results were compared to the analytical solutions for the steady-state and transient temperature for the same setup.
Results The spread of the eight consecutive TPS measurements can be expressed as the coefficient of variation, i.e. the standard deviation divided with the mean value of each measurement. The case with polystyrene had a coefficient of variation of 0.14% after 40s while the polystyrene covered by aluminum had a coefficient of variation of 1.34% after 40s. Thus repetitive measurements with the TPS sensor give results with small variations.
Conclusions When comparing the temperature increase in the numerical simulation of the setup with polystyrene with the TPS measurements the difference after 40s was quite large. For the case with polystyrene covered by aluminum the deviation of the temperature increases was smaller after 40s compared to the setup with polystyrene.
Acknowledgements
Introduction The adoption of Phase Change Materials (PCM) in combination with transparent elements first appeared in the Nineties, and some investigations concerning transparent building envelope components filled with PCM can be found in literature (Manz et al., 1997; Ismail and Henríquez, 2002; Weinläder et al., 2005; Ismail et al., 2008). Although different configurations have been investigated along the years, the basic concept of the PCM glazing system is the same for all the possible layouts. In fact, the PCM layer is used to absorb and store (thanks to the latent heat of fusion) the largest part of the solar infrared (IR) radiation, and to let part of the solar visible (VIS) radiation enter the indoor environment. The aim of this class of technology is therefore to minimise the unwanted heat loss and solar gain thanks to the buffer effect provided by the PCM layer, but still allowing the utilisation of natural light for day-lighting purpose. While the first concepts of PCM glazing systems were mostly developed for continental and cold climates, this technology shows some positive features for warm climates too, as illustrated in a more recent experimental activity (Goia et al., 2010). The optimal configuration of a PCM glazing system is a very complex issue, since several different variables (e.g., the multi-layer structure, the PCM layer thickness, the temperature range of the phase change of the PCM) influence on the final behaviour of the system, and non-linear phenomena often occur. The aim of the work presented in this paper is to deepen the knowledge on PCM glazing systems with respect to two of the main variables that play a role in the problem: The location of the PCM layer and the nominal melting temperature of the PCM. The results illustrated in this paper concern the numerical analysis of south facing PCM glazing systems in a humid subtropical climate (Cfa — Köppen climate classification — Peel et al., 2007).
Materials and methods
Simulations and data processing
Results and discussion
Conclusion
Acknowledgements