THE EFFECT OF STRUCTURE AND THICKNESS ON PERIODIC THERMAL CAPACITY OF BUILDING COMPONENTS

摘要

Thermal capacity of building partitions and their internal thermal structure, that is location of materials of different thermal conductivity, density and specific heat, have an influence on dynamics of the heat transfer processes, caused by external and internal thermal excitations. Dynamic thermal characteristics of building components, which determine the periodic heat transfer processes, are admittances, transmittances and periodic thermal capacities. In this paper, properties of the areal periodic heat capacity of interior and exterior building partitions are examined: its dependence on structure, thickness of masonry layers, surface film resistances and period of temperature variations, and also its asymptotic values for high thickness and low frequency. For wall assemblies composed of lightweight materials, and also for massive walls of very low thickness, approximate proportionality takes place. For heavy structures, the dependence becomes curvilinear, and for very thick walls tends to the constant value, attaining maximum for a comparatively low thickness which is approximately twice the periodic penetration depth. For exterior walls, dependence on the thermal mass factor, and also on thickness of the interior massive layer, has a similar character. Maximum periodic heat capacity for walls with insulation outside appears for thickness of the masonry layer of only 10-12 cm, which is approximately value of the periodic penetration depth.