Emissivity considerations in buildingnext term thermography
Avdelidis, N. P. and Moropoulou, A.
2003 Energy and Buildings, 35(7): 663-667
Author Infrared thermography; Emittance; Temperature; Wavelength; Surface condition; previous termBuildingsnext term
Avdelidis, N. P. and Moropoulou, A., (2003), "Emissivity considerations in buildingnext term thermography", Energy and Buildings, 35(7): 663-667.
Abstract:
In the last 25 years, there have been considerable efforts put into the use and development of infrared thermography on previous buildings term and large structures. As a result, nowadays, there are systems that can be used effectively in outdoor and/or indoor previous building term surveys; indication and monitoring of problems such as voids, detached areas, deposits of humidity, etc. However, the principal problem where infrared previous thermographic term measurements are concerned is the emissivity¡ªemittance of the material(s). Given that an infrared previous camera term detects the radiation emitted by a material under investigation and renders this energy to a temperature¡ªthermal image, the feature that describes the relation between the emitted radiation and the material's temperature, is ed as emissivity. Emissivity is actually a surface property that states the ability of the investigated material to emit energy. Correct emissivity values could provide valuable information concerning the interpretation of thermal images obtained from previous thermographic term surveys. There is a considerable amount of work that has been published on emissivity of different materials and under various circumstances (i.e. temperature, surface condition, wavelength). In this work, a review on emissivity measurement techniques and the importance of emissivity values on previous building term diagnostics was materialised. Furthermore, the emissivity of selected previous building term materials were determined at a variety of temperatures, in the mid and long wavelength regions of the infrared spectrum, using different approaches and were discussed and explained in terms of the approach used, the wavelength and temperature effects, as well as the materials surface state.
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