Window air permeability calculation methodology with regard to temperature loading

Abstract

Air permeability is an important characteristic of windows, which significantly affects the energy consumption of a building and the quality of indoor climate in winter. Existing experimental studies confirm that the air permeability of windows can increase significantly when the outside temperature decreases. This phenomenon is associated with temperature deformations. Nevertheless, currently in the practice of window design the dependence of air permeability on temperature effects is not taken into account. There are methods of windows air permeability experimental determination that take into account temperature loads, but they require unique equipment and are large labor inputs. In view of this, this paper proposes a semi-empirical method for calculating the air permeability of windows with regard to temperature loads, which uses data from standard laboratory tests. This method is based on identifying the system of infiltration channels, which is formed by the window structure, with an elementary system for which the analytical solution of the infiltration equation is known. It can be used for more accurate calculations of the building's energy consumption in the cold period of time, as well as for obtaining a scientifically justified limitation of window structure deflections under the combined action of wind and temperature loads.