Application of Aerial and Terrestrial Thermography for Determining the Building Envelope Thermal Performance

Abstract

It is well known that at a European level, a large building fund must be retrofitted by 2050 to meet the climate and energy targets defined by a reduction of greenhouse gas emissions up to 80 - 95% compared to 1990 levels. In this regard, the proposed recast of the energy performance directive defines a new path: going from nearly Zero Energy Buildings to Zero Emission Buildings for residential and non-residential buildings. Thus, practitioners need more adequate instruments to perform reliable field measurements that can later be used for providing retrofit solutions. In recent years it was observed that infrared thermography could be an excellent substitution for already used techniques that require a significant number of sensors or various equipment. The paper presents an overview of the aerial and terrestrial thermography applications and a description of the THERMOG research project, which focuses on using the thermal imaging approach as both a qualitative and a quantitative approach. The project aims to develop a methodology accompanied by software that evaluates the thermal performance of the building envelope under actual operating conditions using aerial and terrestrial thermography methods. The calculation methodology and the associated software will also be used in the structural and energy expertise activity of buildings, as well as in assessing the energy performance of a new building before the reception phase.

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.…”

“…Results of thermal imaging can be evaluated both qualitatively and quantitatively [3,27]. In the case of qualitative analysis, thermograms are examined for temperature anomalies based on the temperature difference at the location of the presumed defect and the reference zone [8,10,[12][13][14][15][16][17]. The reference zone should be selected similarly to the controlled zone and be in the same heat exchange conditions (located near the inspected area).…”

“…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.…”