Estimating In-Situ R-Value of Highly Insulated Building Walls Based on the Measurement of Temperature and Heat Flux Inside the Wall

Accurate and rapid in situ measurements of the thermal resistance (R-value) of building envelopes are necessary for assessing planned performance and identifying appropriate retrofitting strategies. Although there are several approaches for in situ R-value estimation, the average method of ISO 9869-...

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Bibliographic Details
Published inEnergies (Basel) Vol. 16; no. 15; p. 5714
Main Authors Choi, Doo-Sung, Lee, Ye-Ji, Moon, Ji-Hoon, Kim, Yong-Shik, Ko, Myeong-Jin
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.08.2023
Subjects
average method
Buildings
Energy consumption
Heat
heat flow meter method
highly insulated building wall
in situ measurement
Paper industry
Research methodology
Sensors
Temperature
thermal resistance
United Kingdom
South Korea
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Summary:Accurate and rapid in situ measurements of the thermal resistance (R-value) of building envelopes are necessary for assessing planned performance and identifying appropriate retrofitting strategies. Although there are several approaches for in situ R-value estimation, the average method of ISO 9869-1 based on the heat flow meter method is the most widely used. However, discrepancies between theoretical and in situ R-values are frequently reported in many studies that employ this method. This study aimed to investigate the cause of this discrepancy in estimating in situ R-values of highly insulated building walls using the average method of ISO 9869-1 by conducting long-term experiments. This study was made possible due to a specially constructed test wall wherein more sensors were installed than are required by the ISO 9869-1 standard. The findings showed that discrepancies between heat fluxes on the internal surface and heat passing through the wall is the main cause of the error in in situ R-value estimation. Measurement results from winter showed that deviation from the theoretical R-value was 9.12% for the average method and 0.6% for the extended average method, determined by additionally using the temperature and heat flux inside the wall.
ISSN:1996-1073
1996-1073
DOI:10.3390/en16155714