Development of eco-sustainable plasters with thermal energy storage capability

Abstract

In order to limit the energy demand of buildings, a possible strategy consists in the storage of thermal energy using phase change materials (PCMs). In this work, an innovative PCM-enhanced plaster, fully formulated by using materials coming from natural resources, was developed. The PCM (i.e., a biodegradable material from agricultural resources having a melting temperature of 23 °C) was shape-stabilized with a direct absorption method by using a proper combination of different inorganic powders, taking into account also the final cost of the product and the processability issues. The most important physical properties of the plaster were then investigated following the European standards and compared with those of a natural hydraulic lime commercial plaster. The optimized PCM-enhanced plaster could be classified as a lightweight plaster (LW class according to UNI EN 1015-10) with compressive strength CSI (UNI EN 1015-11) and water absorption class W2 (UNI EN 1015-18). Differential scanning calorimetry tests confirmed the thermal energy storage capability of the PCM-enhanced plaster, even though plaster processing operations slightly decreased the specific melting enthalpy of the PCM within the plaster. Moreover, small-scale simulations were performed through the monitoring of the inner temperature of an insulated box, in which a plaster layer was applied on the internal walls, during heating and cooling ramps. These tests confirmed the thermal energy storage capability of the newly developed plaster around the PCM melting temperature interval.