Thermographic 2D U-value map for quantifying thermal bridges in building façades

Tejedor, Blanca; Barreira, Eva; Almeida, Ricardo M. S. F.; Casals, Miquel

doi:10.1016/j.enbuild.2020.110176

Cited by 34 publications

(15 citation statements)

References 69 publications

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“…The values of linear thermal transmittance Ψ and point thermal transmittance χ depend on the configuration and thermal conductivity of material layers and on how the calculations of one-dimensional thermal transmittance were made, i.e., which values of coefficients U were selected for different building elements and which planes they correspond to. In most cases, heat loss calculations can be performed using the 2D model [45]. Heat losses can be expressed by the linear heat flux Q, [W/m].…”

Section: Simulationsmentioning

confidence: 99%

The Impact of Internal Insulation on Heat Transport through the Wall: Case Study

2020

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This paper presents a case study on how to improve the energy efficiency of an institutional building of significant heritage value through retrofitting the external wall system. This building is located in Upper Silesia, Poland. Due to the architectural value of the facade, thermal insulation had to be applied from the inside. As part of this publication, basing on the measurements and simulations, the authors present the results involving the improvement of energy efficiency of the insulated wall. On this basis, they also demonstrate the impact of insulation from the inside on the change of humidity inside the room. The tests were carried out both quantitatively by means of heat flux measurement and qualitatively by means of infrared temperature measurement. The research was supported by numerical modeling. The obtained results indicate that the thermal insulation used in the form of mineral insulation boards applied from the inside improves thermal insulation of the wall. Thus, heat losses through the examined envelope were limited. Computer simulations indicated that no condensation may occur under the condition considered.

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Section: Simulationsmentioning

confidence: 99%

The Impact of Internal Insulation on Heat Transport through the Wall: Case Study

2020

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“…In addition, they stated that a stochastic analysis could help to reduce the sampling period and only 30 min could be enough for homogeneous specimens. Recently, the authors developed a 2D U-value map to automatically evaluate entire walls pixel-by-pixel under the impact of anomalies using quantitative IRT [34]. The results were checked by HFM method.…”

Section: Quantitative Infrared Thermography Under Steady-state Conditmentioning

confidence: 99%

“…The first NDT technique was carried out according to the procedure extensively reported by Tejedor et al [20], which considers a 1D horizontal heat flux generated by convection and radiation processes under stationary regime. For the real built environment, the recommendations of Tejedor et al [33] and Tejedor et al [34] should be taken into account in terms of operating conditions, thermo-physical properties and test duration. For example, 30 min can be enough for homogeneous samples, while 2-3 h are needed for heterogeneous samples.…”

Section: Laboratory Testing Under Steady-state Conditionsmentioning

confidence: 99%

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

et al. 2020

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Infrared thermography (IRT) has become a commonly applied non-destructive testing method for assessing building envelopes. Like any diagnosis tool, IRT requires an appropriate experience and principle understanding, mainly when the method is used for quantitative analyses. The challenges of the IRT often deal with the dynamic properties of building partitions. Climatic conditions have a certain variability, and the accumulated energy storage in the building components can affect their temperature as well as the calculated thermal performance. This paper aims to analyze how stationary and dynamic regimes of a quantitative IRT test could impact the measured thermal transmittance of heavy multi-leaf walls. Investigation in two European countries with different climatic conditions are reported. In this way, it is discussed which boundary conditions should be guaranteed to provide reliable information about a building envelope using quantitative IRT. In order to check the quality of the measurements, the heat flux meter (HFM) method was also implemented, following the ISO 9869. The research revealed that it could be possible to use short-lasting tests in the climatic conditions of Southern Europe, while long-term tests should be implemented in Northern European countries where climatic conditions are less regular.

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“…Yi [48] proposed an indoor and outdoor coupling simulation evaluation framework for microclimate change to demonstrate the influence of outdoor microclimate on the indoor thermal performance of the buildings. Tejedor [49] proposes the implementation of a 2D U-value map to quantify the influence of thermal bridges on building facades by internal quantitative infrared thermography.…”

Section: Introductionmentioning

confidence: 99%

Thermal Performance Analysis of Heat Collection Wall in High-Rise Building Based on the Measurement of Near-Wall Microclimate

Zhao

et al. 2021

Energies

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Near-wall microenvironment of a building refers to parameters such as wind speed, temperature, relative humidity, solar radiation near the building’s façade, etc. The distribution of these parameters on the building façade shows a certain variation based on changes in height. As a technology of passive heating and ventilation, the effectiveness of this application on heat collection wall is significantly affected by the near-wall microclimate, which is manifested by the differences, and rules of the thermal process of the components present at different elevations. To explore the feasibility and specificity of this application of heat collection wall in high-rise buildings, this study uses three typical high-rise buildings from Zhengzhou, China, as research buildings. Periodic measurements of the near-wall microclimate during winter and summer were carried out, and the changing rules of vertical and horizontal microclimate were discussed in detail. Later, by combining these measured data with numerical method, thermal process and performance of heat collection wall based on increasing altitude were quantitatively analyzed through numerical calculations, and the optimum scheme for heat collection wall components was summarized to provide a theoretical basis for the structural design of heat-collecting wall in high-rise buildings.

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Thermographic 2D U-value map for quantifying thermal bridges in building façades

Cited by 34 publications

References 69 publications

The Impact of Internal Insulation on Heat Transport through the Wall: Case Study

The Impact of Internal Insulation on Heat Transport through the Wall: Case Study

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

Thermal Performance Analysis of Heat Collection Wall in High-Rise Building Based on the Measurement of Near-Wall Microclimate

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