Influence of placement of the window block on wall thickness on heat losses

Interface of the window block to an external wall is one of the most responsible knots at thermal engineering design of envelope. For reduction of thermal losses through knot, it is necessary to consider not only design features of a window and wall, but also an arrangement of the window block in the thickness of a wall. In this article the assessment of influence of placement of the window block on thickness of the wall made of constructive and thermal-insulating materials on additional losses of warmth through knot is executed. Various options of an arrangement of the window block on wall thickness are considered: on depth of "quarter" and in the middle of a wall. From the received results of graphic calculation of the two-dimensional stationary temperature field it is established that specific additional losses of warmth in knot of interface of the window block to a wall with application of "quarter" are 38% more, than at placement of the window block in the middle of a wall. Placement of the window block in a neutral zone of an external wall reduces specific additional losses of warmth and increases thermal efficiency of knot. Calculated values of specific additional thermal losses through knot of interface of the window block to a wall are agreed with the data of DIN 4108 of Bbl 2:2004-01 that confirms correctness of results of research. The results of graphic calculation are preliminary and can be specified by numerical modeling of the two-dimensional stationary temperature field. Results of calculation of the temperature field can be used at specification of standard requirements to placement of the window block on thickness of the wall made of constructional and thermal-insulating materials in construction and by means of thermorenovation