Novel in situ measurement methods of the total heat transfer coefficient on building walls

François, Adrien; Ibos, Laurent; Feuillet, Vincent; Meulemans, Johann

doi:10.1016/j.enbuild.2020.110004

Cited by 13 publications

(9 citation statements)

References 20 publications

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“…si measured with contact sensors on a nearby sound area. The extrapolation is performed thanks to infrared thermography measurements as well as quantification of the total heat transfer coefficient h. This extrapolation process was developed and validated by the authors in [14]. It is presented in section 5.3.1.…”

Section: General Methodsmentioning

confidence: 99%

“…The total heat transfer coefficient h is measured with a specific device presented in the next section. The heat flux extrapolation procedure was validated in [14].…”

Section: Heat Flux Extrapolationmentioning

confidence: 99%

“…The main challenge consists in quantifying the local heat transfer coefficient without knowing the operative temperature. For this purpose, the authors developed and tested several in situ measurements methods of h overcoming this issue (see [14] and [72]). The method selected here is the one referred as the "Harmonic Excitation" (HE) method in [14].…”

Section: Overall Heat Transfer Coefficient Measurementmentioning

confidence: 99%

“…For this purpose, the authors developed and tested several in situ measurements methods of h overcoming this issue (see [14] and [72]). The method selected here is the one referred as the "Harmonic Excitation" (HE) method in [14]. It was chosen for its robustness and ease of implementation.…”

Section: Overall Heat Transfer Coefficient Measurementmentioning

confidence: 99%

“…By measuring the surface temperature and heat flux fields on the thermal bridge, this same inverse technique may be applied to estimate the equivalent thermal resistance of a non-homogeneous wall. The temperature and heat flux are extrapolated from a sound area to the thermal bridge using infrared thermography (IRT) and a device to estimate the global surface heat transfer coefficient [14]. The method is validated on a fullscale wall built inside a climate chamber.…”

mentioning

confidence: 99%

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In situ measurement method for the quantification of the thermal transmittance of a non-homogeneous wall or a thermal bridge using an inverse technique and active infrared thermography

François

Ibos

Feuillet

et al. 2021

Energy and Buildings

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Thermal bridges tend to increase overall buildings energy demand and might cause water condensation problems. They are thermally characterized by a linear transmission coefficient ψ or a point transmission coefficient χ. Today, most studies of thermal bridges are based on theoretical or numerical calculations. Standardized methods define default values and assumptions to make in simple or detailed simulations. The few existing in situ characterization methods of thermal bridges are based on steady-state assumptions. This makes them highly sensitive to weather conditions and often requires very long measurements. The present paper proposes a novel active method for the in situ characterization of a thermal bridge. It generalizes a measurement of a homogeneous wall thermal resistance. The indoor air is rapidly heated for a few hours (typically 6) and the wall thermal response is analyzed with an inverse technique based on a white-box model. Surface temperatures and heat fluxes are measured with contact sensors on a sound area and these quantities are then extrapolated to nearby thermal bridges using infrared thermography. The total heat transfer coefficient, required in the heat flux extrapolation process, is monitored with a specific device. The method is validated on a full-size loadbearing wall built inside a climate chamber. The mechanical supports, holding the internal insulation system implemented on the wall, generate several thermal bridges. The ψ-values estimated by the active method are less than 20% away from steady-state measurements taken as reference. Many configurations were tested with constant and varying external temperature and the method proved its robustness to these unsteady conditions.

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Section: General Methodsmentioning

confidence: 99%

“…The total heat transfer coefficient h is measured with a specific device presented in the next section. The heat flux extrapolation procedure was validated in [14].…”

Section: Heat Flux Extrapolationmentioning

confidence: 99%