Recent studies have shown that considering the values of superficial mass (Ms) and periodic thermal transmittance (Ymn) of external walls is not sufficient to achieve energy savings, particularly in summer. For this reason experimental reference values of the internal areal heat capacity (k1) were introduced. This study aims to understand the interdependency between some thermal parameters (U, Ms, ϕ, Fa,Ymn, k1) of massive and lightweight walls with respect to their energy performance in use in office build-ings in Southern Europe. The study has analyzed eight walls with Italian standard U and Ymn values. These walls have been then modified in order to reach k1values corresponding to the reference ones. The energy demand to ensure a defined level of indoor thermal comfort has been verified with thermodynamic simulations on a virtual test-room localized in two Italian cities, characterized by different climate conditions. The research results are: to develop design change strategies for external walls to achieve the k1ref-erence values; to quantify the thermal annual energy demand of a virtual test-room equipped with the sample walls and then equipped with the improved walls; to compare the energetic and economic impact for the improved walls against the sample ones.
External walls design: the role of periodic thermal transmittance and internal areal heat capacity
ROSSI, MONICA;
2014-01-01
Abstract
Recent studies have shown that considering the values of superficial mass (Ms) and periodic thermal transmittance (Ymn) of external walls is not sufficient to achieve energy savings, particularly in summer. For this reason experimental reference values of the internal areal heat capacity (k1) were introduced. This study aims to understand the interdependency between some thermal parameters (U, Ms, ϕ, Fa,Ymn, k1) of massive and lightweight walls with respect to their energy performance in use in office build-ings in Southern Europe. The study has analyzed eight walls with Italian standard U and Ymn values. These walls have been then modified in order to reach k1values corresponding to the reference ones. The energy demand to ensure a defined level of indoor thermal comfort has been verified with thermodynamic simulations on a virtual test-room localized in two Italian cities, characterized by different climate conditions. The research results are: to develop design change strategies for external walls to achieve the k1ref-erence values; to quantify the thermal annual energy demand of a virtual test-room equipped with the sample walls and then equipped with the improved walls; to compare the energetic and economic impact for the improved walls against the sample ones.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
