ADDITIONAL HEAT LOSSES AT THE JUNCTIONS OF THE WINDOW FRAMES AND ENCLOSING STRUCTURES

Abstract

The current state of housing and communal services, which have been built by the end of the 90s, requires complete modernization and a significant increase of energy efficiency. Global trends in energy efficiency of buildings are aimed at changing energy consumption to almost zero level (nZEB). Most of the measures aimed at achieving nZEB refer to measures of improvement the thermophysical properties of enclosures. With the improvement of the thermophysical properties of the enclosures, the influence of the thermally conductive inclusions that occur at the junctions of the window structures / reinforced concrete slab of the ceiling to the outer wall, etc., increases significantly.

The paper contains 2D-models built in the THERM – a software for studying temperature fields at the junctions of linear heat-conducting inclusions. We have simulated heat-conducting fields for two variants of external walls with improved thermophysical properties of enclosures that conform to modern requirements for thermal protection. The calculation was made for the climatic conditions of Kyiv.

It is established that for the same thickness of the outer wall, the replacement of the bearing layer of the silicate bricks structure with a aerocrete blocks improves the resistance to heat transfer by 2 times. From the point of view of influence of linear heat-conducting inclusions in places of adjunction of a window frame to an external wall is observed the opposite effect, when there is a bigger influence in a wall made of the aerocrete blocks. Taking into account linear and point heat-conducting inclusions leads to a deterioration of the resistance to heat transfer of the outer wall made of silicate bricks by 20%, and of the aerocrete blocks - by 33%. Consideration of heat-conducting inclusions even for a construction without difficult constructive decisions of protections leads to increase in heat losses.