Assessing Overall Thermal Conductance Value of Low-Rise Residential Home Exterior Above-Grade Walls Using Infrared Thermography Methods
Authors: Matthew D. Baffa
Infrared thermography is a non-destructive test method used to estimate surface temperatures based on the amount of electromagnetic energy radiated by building envelope components. These surface temperatures are indicators of various qualitative building envelope deficiencies such as locations and extent of heat loss, thermal bridging, damaged or missing thermal insulation, air leakage, and moisture presence in roof, floor, and wall assemblies. Although infrared thermography is commonly used for qualitative deficiency detection in buildings, this study assesses its use as a quantitative method to estimate the overall thermal conductance value (U-value) of the exterior above-grade walls of a study home. The overall U-value of exterior above-grade walls in a home provides useful insight into the energy consumption and thermal comfort of a home. Three methodologies from the literature were employed to estimate the overall U-value by equating conductive heat loss through the exterior above-grade walls to the sum of convective and radiant heat losses of the walls. Outdoor infrared thermography field measurements of the exterior above-grade wall surface and reflective temperatures and emissivity values for various components of the exterior above-grade wall assemblies were carried out during winter months at the study home using a basic thermal imager device. The overall U-values estimated from each methodology from the literature using the recorded field measurements were compared to the nominal exterior above-grade wall overall U-value calculated from materials and dimensions detailed in architectural drawings of the study home. The nominal overall U-value was validated through calendarization and weather normalization of utility bills for the study home as well as various estimated heat loss quantities from a HOT2000 computer model of the study home and other methods. Under ideal environmental conditions, the estimated overall U-values deviated from the nominal overall U-value between ±2% to ±33%. This study suggests infrared thermography can estimate the overall U-value of exterior above-grade walls in low-rise residential homes with a fair amount of accuracy.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1317094Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 622
 D. J. Titman, “Applications of thermography in non-destructive testing of structures,” NDT & E International, vol. 34, no. 2, pp. 149–154, Mar. 2001.
 N. P. Avdelidis, and A. Moropoulou, “Emissivity considerations in building thermography,” Energy and Buildings, vol. 35, no. 7, pp. 663–667, Aug. 2003.
 P. A. Fokaides, and S. A. Kalogirou, “Application of infrared thermography for the determination of the overall heat transfer coefficient (U-Value) in building envelopes,” Applied Energy, vol. 88, no. 12, pp. 4358–4365, Dec. 2011.
 C. A. Balaras, and A. A. Argiriou, “Infrared thermography for building diagnostics,” Energy and Buildings, vol. 34, no. 2, pp. 171-183, Feb. 2002.
 A. Moropoulou, M. Koui, N. P. Avdelidis, E. T. Delegou, and S. Kouris, “Calculating the emissivity of building materials for infrared thermographic applications,” in Proceedings of the 6th International Conference of the Slovenian Society of NDT, 2001, pp. 333–337.
 R. A. Thomas, The thermography monitoring handbook. Oxford: Coxmoor Publishing, 1999.
 A. Kylili, P. A. Fokaides, P. Christou, and S. A. Kalogirou, “Infrared thermography (IRT) applications for building diagnostics: A review,” Applied Energy, vol. 134, pp. 531–549, Dec. 2014.
 S. Datcu, L. Ibos, Y. Candau, and S. Matteï, “Improvement of building wall surface temperature measurements by infrared thermography,” Infrared Physics & Technology, vol. 46, no. 6, pp. 451–467, Aug. 2005.
 E. Barreira, and V. P. de Freitas, “Evaluation of building materials using infrared thermography,” Construction and Building Materials, vol. 21, no. 1, pp. 218–224, Jan. 2007.
 J. M. Hart, A practical guide to infra-red thermography for building surveys. Watford: Building Research Establishment, 1991.
 R. Albatici, A. M. Tonelli, and M. Chiogna, “A comprehensive experimental approach for the validation of quantitative infrared thermography in the evaluation of building thermal transmittance,” Applied Energy, vol. 141, pp. 218–228, Mar. 2015.
 B. Tejedor, M. Casals, M. Gangolells, and X. Roca, “Quantitative internal infrared thermography for determining in-situ thermal behaviour of façades,” Energy and Buildings, vol. 151, pp. 187–197, Jun. 2017.
 B. Lehmann, K. Ghazi Wakili, T. Frank, B. Vera Collado, and C. Tanner, “Effects of individual climatic parameters on the infrared thermography of buildings,” Applied Energy, vol. 110, pp. 29-43, Oct. 2013.
 A. Marshall, J. Francou, R. Fitton, W. Swan, J. Owen, and M. Benjaber, “Variations in the U-Value Measurement of a Whole Dwelling Using Infrared Thermography under Controlled Conditions,” Buildings, vol. 8, no. 3, pp. 46, Mar. 2018.
 R. Albatici, and A. M. Tonelli, “Infrared thermovision technique for the assessment of thermal transmittance value of opaque building elements on site,” Energy and Buildings, vol. 42, no. 11, pp. 2177–2183, Nov. 2010.
 E. Grinzato, V. Vavilov, and T. Kauppinen, “Quantitative infrared thermography in buildings,” Energy and Buildings, vol. 29, no. 1, pp. 1–9, Dec. 1998.
 ISO 9869 Thermal insulation - Building elements - In-Situ Measurement of Thermal Resistance and Thermal Transmittance. Part 1: Heat Flow Meter Method, 2014.
 M. O’Grady, A. A. Lechowska, and A. M. Harte, “Infrared thermography technique as an in-situ method of assessing heat loss through thermal bridging,” Energy and Buildings, vol. 135, pp. 20–32, Nov. 2016.
 EN ISO 6946 Building components and building elements – thermal resistance and thermal transmittance – Calculation method, 2007.
 S. Doran, Field investigations of the thermal performance of construction elements as built. BRE Client Report No. 78132. A DETR Framework Project Report. East Kilbride: Building Research Establishment (BRE), 2001.
 L. Evangelisti, C. Guattari, P. Gori, and R. D. L. Vollaro, “In situ thermal transmittance measurements for investigating differences between wall models and actual building performance,” Sustainability, vol. 7, no. 8, pp. 10388–10398, Aug. 2015.
 UNI 10351 Building Materials. Thermal Conductivities and Vapor Permeabilities, 1994.
 E. Lucchi, “Applications of the infrared thermography in the energy audit of buildings: A review,” Renewable and Sustainable Energy Reviews, vol. 82, no. 3, pp. 3077–3090, Feb. 2018.
 M. V. Jokl, “Thermal comfort and optimum humidity Part 1,” Acta Polytechnica, vol. 42, no. 1, 2002.
 ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy, 2017.
 Statistics Canada, Report on Energy Supply and Demand in Canada 1990–2015. Ottawa: Statistics Canada, 2017
 Government of Ontario, Ontario’s Five Year Climate Change Action Plan 2016 - 2020. Government of Ontario, 2016.
 Canadian Mortgage and Housing Corporation, Housing Market Outlook - Canada Edition. Canadian Mortgage and Housing Corporation, 2017.
 T. A. Reddy, J. F. Kreider, P. S. Curtiss, and A. Rabl, Heating and Cooling of Buildings: Design for Efficiency, Revised Second Edition. Boca Raton: CRC Press, 2009.
 ASHRAE, 2009 ASHRAE Handbook - Fundamentals (Har/Cdr edition). Atlanta: ASHRAE, 2009.
 Environment Canada. 2016. Temperature – Monthly data for Vaughan. Retrieved March 11, 2016, from https://vaughan.weatherstats.ca/charts/temperature-monthly.html.
 DIN EN ISO 9001. Quality management systems — Requirements, 2008.
 R. P. Madding, “Emissivity measurement and temperature correction accuracy considerations,” in Thermosense XXI, Orlando, 1999, pp. 393-402.
 R. Albatici, F. Passerini, A. M. Tonelli, and S. Gialanella, “Assessment of the thermal emissivity value of building materials using an infrared thermovision technique emissometer,” Energy and Buildings, vol. 66, pp. 33–40, Nov. 2013.
 R. -H. Zhang, et al., “Study of emissivity scaling and relativity of homogeneity of surface temperature,” International Journal of Remote Sensing, vol. 25, no. 1, pp. 245–259, Jan. 2004.
 ASTM E1862 Standard test methods for measuring and compensating for reflected temperature using infrared imaging radiometers, 2002.
 G. Dall’O, L. Sarto, and A. Panza, “Infrared screening of residential buildings for energy audit purposes: results of a field test,” Energies, vol. 6, no. 8, pp. 3859–3878, Jul. 2013.
 I. Valovirta, and J. Vinha, “Water vapor permeability and thermal conductivity as a function of temperature and relative humidity,” Performance of exterior envelopes of whole buildings IX, 2004.
 N. B. Hutcheon, and G. O. P. Handegord, Building science for a cold climate (First Edition). Toronto: John Wiley & Sons, 1984.
 S. Lorente, “Heat losses through building walls with closed, open and deformable cavities,” International Journal of Energy Research, vol. 26, no. 7, pp. 611–632, Jun. 2002.
 J. Xamán, G. Álvarez, L. Lira, and C. Estrada, “Numerical study of heat transfer by laminar and turbulent natural convection in tall cavities of façade elements,” Energy and Buildings, vol. 37, no. 7, pp. 787–794, Jul. 2005.
 A. Colantonio, “Identification of convective heat loss on exterior cavity wall assemblies,” in Thermosense XXI, Orlando, 1999, pp. 514–520.
 B. Kersten, and J. van Schijndel, “Modeling the Heat Exchange in Cavities of Building Constructions Using COMSOL Multiphysics®”, n.d.
 S. -Y. Wu, L. Xiao, Y. Cao, and Y.-R. Li, “Convection heat loss from cavity receiver in parabolic dish solar thermal power system: A review,” Solar Energy, vol. 84, no. 8, pp. 1342–1355, Aug. 2010.
 D. Haltrect, and K. Fraser, “Validation of HOT2000TM Using HERS BESTEST”, in Proc. Building Simulation, Prague, 1997, pp. 1-8.