David Marín García

Threshold Values for Energy Loss in Building Façades Using Infrared Thermography

The main factor in energy savings is the thermal envelope of buildings, where energy losses or gains with the exterior occur. This work proposes a new methodology to detect the most significant sectors in energy transmission through infrared thermography and the thermal intensity assessment of each opaque area, building element or thermal bridge, taking into account different values of wind speed. Thermal intensity values are then compared with the corresponding thermal transmittance threshold given in the regulations for each country, depending on the climate area. This method provides a specific view of the building elements and of the overall envelope in terms of energy loss using thermal intensity instead of the traditional heat transfer analysis. It thus results in quantitative energy loss through the shell. The main goal of this work is to select building elements or zones of a thermal envelope according to their energy losses in order to avoid an indiscriminate intervention on the opaque parts of envelopes. This research is significant as few studies have analysed global energy losses in buildings, quantitatively evaluating the thermal intensity of all the components of the opaque parts of facades. This study also advances in analysing the influence of different wind speeds in facades in order to assess the thermal behaviour of buildings when quasi-steady condition is lost.