The influence of non-stationary thermal conditions in the determination of the thermal resistance of the fence
Abstract
The influence of non-stationary thermal conditions in the determination of the thermal resistance of the fence
Incoming article date: 28.11.2013Reconstruction of buildings inevitably entails improving the thermal protection of premises, however, the development of measures for the thermal insulation of the existing building structures is impossible without evaluation of thermal characteristics of these structures, primarily the resistence to heat transfer. Evaluation of the materials according to their characteristics reference is often not possible. The main causes is the lack of information about construction materials to the inner layers of the long-erected buildings. Arise a number of difficulties in conducting field surveys due to the practical absence of the stationary conditions. Heat flux on the surface can change simultaneously with changes in temperature, as walling have thermal inertia, and need some time to change the temperature distribution in the structure thickness. To determine the actual heat transfer resistance of enclosing structures must take into account the dynamics of change of temperature and heat flow on the surface of the enclosure. When determining the actual heat transfer resistance needs to consider the time distribution of heat waves through the walling.
Keywords: non-stationary thermal conditions, cladding, thermophysical characteristics, thermal resistance