Non-Stationary Thermal Performance Evaluation of External Façade Walls Under Central European Summer Conditions
Abstract
Thermal response of building envelope exerts a substantial influence on the formation of overall indoor comfort conditions as well as on the energy performance of buildings. For the majority of Central and Northern European countries it can be said that legislators as well as designers focus primarily on the optimization of building performance in heating season. Nevertheless, predictions for the future show the potential for large increase in cooling demand due to overheating of buildings. In this context, the focus of the presented work was to evaluate the non-stationary performance of different façade walls (lightweight and heavyweight construction systems) during typical Central European summer conditions. In addition to the influence of wall composition, the impact of orientation and high intensity passive cooling on thermal response was also investigated. The results showed differences in the summer time performance of lightweight and heavyweight envelopes, whereas lightweight façade walls had worse summer time thermal response. Furthermore, substantial differences in thermal behaviour of east, south and west faced walls were identified, with wall orientation having greater effect in the cases of walls with higher thermal transmittance and when constant ventilation regimes were used. However, among all the analysed parameters, high intensity passive cooling was identified to have the greatest influence on the summer time thermal behaviour of façade walls.