Infrared thermography application for in-situ determination of the building envelope thermal performance

Abstract

During the phase of creating energy audit documentation, many calculations are needed when evaluating the thermal performance of building envelope components due to a large number of distinct components and junctions. Several computer programs are available to assess buildings’ energy consumption, using the thermal performance of building envelope elements as input data. These thermal performances are often provided with varying degrees of accuracy, typically only for the current field of the component, without considering the impact of thermal bridges. However, when using linear heat transfer coefficients ψ, the details provided in thermal bridges’ atlases do not cover all the case studies encountered in the current design, which often requires approximate details. In some cases, the technical documentation of the building is unavailable, which leads to various assumptions about the detailing of the building envelope and a non-realistic picture of the energy performance of the assessed building. The paper presents a methodology and accompanying software called THERMOG that evaluates the thermal performance of the building envelope under actual operating conditions using aerial and terrestrial thermography methods. The paper presents initial findings from some case studies used to calibrate the developed methodology.

Analyzing Thermal Images to Evaluate Thermal Protection in Residential Structures: Lessons from Russian Practices

“…The comprehensive solution to the problems discussed in the article and the implementation of capabilities for qualitative and quantitative assessment of thermal images during construction thermography allow answering the question: «Does the control object meet the current requirements for thermal protection or not?» If «No», a list of possible energy-saving measures aimed at complete or partial resolution of the identified issues is compiled [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. For instance, in the case of detecting localized (fragmentary) excess heat losses through the external enclosing structures of a construction object, an energy-saving measure could be the external thermal insulation of walls using sprayed polyurethane foam with a protective coating or liquid insulation.…”

“…The reference zone should be selected similarly to the controlled zone and be in the same heat exchange conditions (located near the inspected area). There are rules for qualitative thermogram analysis that enhance the effectiveness of detecting and assessing temperature anomalies [3][4][5][6][7][8][9][11][12][13][14][15][16][17][18][19]: Supplementing the thermogram with a visible image (photograph). Computer overlay of visible and thermal images.…”

“…The placement of the thermal imager is chosen so that the surface of the object is in direct view at an observation angle of not less than 60°. Using an overview thermogram of the external surfaces of enclosing structures, areas with compromised thermal insulation properties are identified, subsequently subjected to detailed thermography from the internal side of enclosing structures [3][4][5][6][7][8][9][10]. Thermography can be either overview or detailed [5][6][7][8][9][10][11][12][13][14][15].…”

“…Using an overview thermogram of the external surfaces of enclosing structures, areas with compromised thermal insulation properties are identified, subsequently subjected to detailed thermography from the internal side of enclosing structures [3][4][5][6][7][8][9][10]. Thermography can be either overview or detailed [5][6][7][8][9][10][11][12][13][14][15]. Overview thermography involves thermal imaging of external and/or internal surfaces of enclosing structures.…”