ABSTRACT
Composite walls are analyzed using a theory of dynamic thermal networks presented in a companion paper. The heat loss dynamics of a wall with constant indoor temperature and variable outdoor temperature is determined by the so-called transmittive weight function. This weight function for preceding boundary temperatures is obtained from a step response solution.
Three different walls (gypsum, brick or concrete combined with insulation) are studied. The weight functions and the effective outdoor temperatures (from a heat-loss point of view) are shown. The effect of the order between the layers is discussed. There is a strong effect of moving a part of the thermal insulation to the non-insulated side. The effects of the thickness of insulation and of concrete on the weight function is studied. A handy formula for the annual heating cost with a variable energy price is presented. The climate and energy price are completely separated from the thermal characteristics of the wall as expressed by the weight function.
