Determination of the thermal resistance of walls through a dynamic analysis of in-situ data

Abstract

In this paper a method for calculating the thermal resistance of a wall through the dynamic analysis of both heat flux and surface temperature samples is presented. Such a method models the transient thermal response of the wall through a linear relation with constant parameters that links the instantaneous heat flux at the inner surface of the wall to the temperature difference between the surfaces of the same wall at the same instant. Additionally, the linear relation mentioned above also links a certain number p of terms formed, each of them, by differences of the same variables related to the considered instant and to p previous instants. The number of the parameters of the model is derived through the principles of hypothesis testing. At this stage, the proposed method is applied to simulated data as indicated by the proposal of European standard 12494, 1996. The results shown here have been concerning with different typologies of wall, namely light, medium and heavy, as well as with 24 data sets obtained by picking data in the one-year time series. Although limited to winter and summer measurement periods, a comparison between the proposed method and classic average one is also performed.