A parametric study of phase change material characteristics when coupled with thermal insulation for different Australian climatic zones

The development of lightweight structures in the building industry has made the usage of thermal mass more difficult. Hence, phase change materials (PCMs) due to their latent heat storage are a favourable alternative which can be coupled with lightweight constructions. This paper explores the relationship between PCM thicknesses, PCM transition temperatures, insulation, building orientations and energy consumption. For this exploration, a full-scale calorimeter was utilized to validate a model; through numerical simulations, the model was then used for four different climates of Australia. It was found that for all the climates, increasing PCM thicknesses ameliorates the overall energy saving, and the saving proportion is dependent on both the climate conditions and envelope thermal resistance (R-values). For low R-value opaque envelopes, the optimal transitional temperature is contingent upon the PCM thicknesses. Moreover, using insulation in sub-tropical, hot-dry, and cold climates enhances PCM efficiency and stabilizes the optimal PCM melting temperature for differing thicknesses; also, augmenting insulation thickness lowers the importance of PCM thicknesses. However, the use of well-insulated envelopes in tropical climates has an adverse impact on PCM efficacy due to the hindrance of night-time energy release. Finally, the PCM energy saving fully depends upon the building orientation, while the PCM optimum temperature is not conditional on this factor.