Improving Energy Efficiency Through Artificial Inertia: Use of Phase Change Materials in Light, Internal Components

Phase Change Materials (PCM’s) are characterised by a large thermal capacity and by melting temperatures close to those associated with human comfort. Thanks to the “artificial inertia” they can give a building, they can be used in components such as wallboards, floors, etc. in order to: - store free heat gains during winter days and release energy during the night; - reduce overheating risks in summer, especially in well-insulated Structure / Envelope constructions (Str/En) with poor thermal capacity (lightweight construction), thanks to the peak-shaving effect; - store off-peak energy – both in winter and summer – in order to have, during the day, a warm / cool surface that contributes to irradiative comfort in winter / summer. An extensive experimental campaign was set up in Ancona (I) and Gävle (S) during the EU-FP5-funded research called C-TIDE (Changeable Thermal Inertia Dry Enclosures), involving Politecnico di Milano, Università Politecnica delle Marche, BMG and three SME. Different configurations were studied and tested on site, allowing to understand the potential for integration of hydrated salt PCM’s in lightweight floors and internal partitions. The experimental campaign included: - prototyping a specific packaging system based on aluminium pouches (the “PCM blanket”); - testing the blanket – both in wall and floors – in experimental boxes with controlled temperature conditions; - testing the implication of sandwiching the blanket in a traditional plasterboard wall from the point of view of assembly procedures, time, everyday use, etc. The results, which were supported by mathematical modelling using the FDM method, show a good potential for integration of PCM’s in light plasterboard components. PCM’s work as a thermal flywheel, reducing the peak loads (for heating and / or cooling) and energy consumption.