Equivalent model of multilayer enclosing structures for calculations of non-stationary heat transfer

The model of the enclosing structure, which is proposed to be used in non-stationary heat exchange between building premises and the external environment calculations is presented. The model is in representing of multilayer enclosing structure as single-layer with the same values of its heat transfer resistance and characteristic time of stationary heat transfer establishment. Various single-layer enclosing structures characteristic time calculations results are presented and basing on their statistical analysis, an analytical model for determining the volumetric heat capacity of the equivalent enclosing structure material with known enclosing thickness is proposed. The thermal conductivity coefficient of such an enclosing structure material is determined analytically from a given heat transfer resistance. Using the example of a massive wall insulated from the outside, it is shown that the proposed model of a single-layer structure gives a similar dynamics of the transition process as via calculating of the initial structure, with deviations much shorter than the characteristic time. Moreover, deviations occur only at the beginning of the transition process.