Energy and environmental performance of building facades integrated with phase change material in subtropical Hong Kong

In the past decade, the application of phase change material (PCM) wallboard in building facade has gained wide attention around the world. For successful application of PCM integrated building facade, a number of crucial factors including thermo-physical properties of PCM, outdoor climate condition. operating schedule of building, investment cost and tariff structure should be taken into account. In this study, a typical residential flat with PCM integrated external walls constructed in the living room and bedroom was modeled and the thermal/energy performance was investigated. The effect of PCM integrated wall's orientation was also evaluated. Through computer simulations, it was found that the living room of a residential flat with west-facing integrated external wall could perform better. It gave a comparatively higher decrease in the interior surface temperature up to a maximum of 4.14%. Moreover, an annual energy saving of 2.9% in air-conditioning system was achieved. However, a long cost payback period of 91 years makes the PCM integrated building facade economically infeasible. On the other hand, the energy payback period was estimated as 23.4 years for this building case, indicating that the energy saving can surpass the embodied energy of PCM wallboard and mitigate the greenhouse gas emission. (C) 2011 Elsevier B.V. All rights reserved.