A numerical study of external building walls containing phase change materials (PCM).

Abstract Phase Change Materials (PCMs) have been receiving increased attention, due to their capacity to store large amounts of thermal energy in narrow temperature ranges. This property makes them ideal for passive heat storage in the envelopes of buildings. To study the influence of PCMs in external building walls, a one-dimensional transient heat transfer model has been developed and solved numerically using a finite difference technique. Different external building wall configurations were analyzed for a typical building wall by varying the location of the PCM layer, the orientation of the wall, the ambient conditions and the phase transition temperature of the PCM. The integration of a PCM layer into a building wall diminished the amplitude of the instantaneous heat flux through the wall when the melting temperature of the PCM was properly selected according to the season and wall orientation. Conversely, the results of the work show that there is no significant reduction in the total heat lost during winter regardless of the wall orientation or PCM transition temperature. Higher differences were observed in the heat gained during the summer period, due to the elevated solar radiation fluxes. The high thermal inertia of the wall implies that the inclusion of a PCM layer increases the thermal load during the day while decreasing the thermal load during the night.

[1]  Zhu Neng,et al.  Experimental study and evaluation of latent heat storage in phase change materials wallboards , 2007 .

[2]  Joseph Andrew Clarke,et al.  Numerical modelling and thermal simulation of PCM–gypsum composites with ESP-r , 2004 .

[3]  Minoru Mizuno,et al.  Numerical study on a low energy architecture based upon distributed heat storage system , 2001 .

[4]  J. Duffie,et al.  Analysis of collector-storage building walls using phase-change materials , 1991 .

[5]  Slobodan Gadžurić,et al.  New materials for solar thermal storage—solid/liquid transitions in fatty acid esters , 2003 .

[6]  J. Carmeliet,et al.  Convective heat transfer coefficients for exterior building surfaces: Existing correlations and CFD modelling , 2011 .

[7]  Joseph Virgone,et al.  Optimization of a Phase Change Material Wallboard for Building Use , 2008 .

[8]  K. Peippo,et al.  A multicomponent PCM wall optimized for passive solar heating , 1991 .

[9]  Hazim B. Awbi,et al.  Performance of phase change material boards under natural convection , 2009 .

[10]  Hongfa Di,et al.  Application of latent heat thermal energy storage in buildings: State-of-the-art and outlook , 2007 .

[11]  Uroš Stritih,et al.  Solar heat storage wall for building ventilation , 1996 .

[12]  Philip C. Eames,et al.  The application of a validated numerical model to predict the energy conservation potential of using phase change materials in the fabric of a building , 2006 .

[13]  D. A. Neeper,et al.  Thermal dynamics of wallboard with latent heat storage , 2000 .

[14]  M. Rady.  Granular phase change materials for thermal energy storage: experiments and numerical simulations , 2009 .

[15]  H. Awbi,et al.  Natural convection from heated room surfaces , 1999 .

[16]  S. Thelandersson,et al.  Estimating extreme values of thermal gradients in concrete structures , 2011 .