Evaluation of the thermal performance of hollow brick walls with gypsum-pcm plasters

Abstract

As EU buildings account for 40% of the total energy consumption, it is important to take measures to reduce these needs and, consequently, reduce the EU energy dependency as well as the greenhouse gas emissions, in accordance with what is prescribed in the EU Energy Efficiency in Buildings Directive (EPBD) and reinforced with the "EPBD-recast". Some of the most effective ways of improving buildings energy performance are by increasing thermal insulation of the building elements, reducing heat losses and summer heat gains and by storing the energy from solar gains. Latent heat storage using phase change materials (PCM) can be used as an effective way of regulating indoor temperatures. The use of PCM is then a way of achieving thermal mass without increasing the weight of the buildings and improving the thermal comfort conditions inside buildings by increasing thermal energy storage. The good thermal characteristics of PCM can be used in residential or office buildings, in new and existing ones as a passive way of saving energy and reducing running costs for both heating and cooling seasons. Therefore it is possible to achieve an adequate behaviour of buildings reducing the energy needs, using solar gains, night cooling and off-peak electricity and, at the same time, increasing the comfort conditions inside the buildings, reducing temperature fluctuations and peak temperatures. In this study, gypsum and lime based interior plastering systems, incorporating phase change materials were studied and the results from experiments made in an adiabatic room of a real scale test building of the University of Minho are presented. Gypsum and lime plaster were chosen as they have good insulating properties due to low conductivity and high thermal inertia, good hygrometric behaviour, acting as a moisture regulator, high composition stability, good tensile and flexural strength, absorbing background movement, fire resistance and good acoustic properties.