Comparison of the Experimental Measurement Methods for Building Envelope Thermal Transmittance

Lu, Xinrui; Memari, Ali M.

doi:10.3390/buildings12030282

Cited by 12 publications

(4 citation statements)

References 46 publications

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“…Lu and Memari [42] presented a comparison of measurement methods for the thermal transmittance of building envelopes. These methods were highly precise.…”

Section: Discussionmentioning

confidence: 99%

Renovation of Modernist Housing Developments in the Pursuit of Modernity for Well-Being and Clean Energy

et al. 2022

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The research concerns renovation variants for modernist housing estates built in Szczecin, Poland during 1918–1925 and in Bialystok, Poland during 1950–1990. These buildings are now substandard in many ways; functionally, aesthetically, technically, and ecologically they do not fulfil the current energy efficiency standards. Some of them have architectural heritage, so not all energy-saving technologies can be applied. Renovations must include energy-saving improvements and the use of renewable energy sources. Equally important is the well-being of residents, meaning the quality of the apartments should be increased. The aim of this research was to analyze the renovation options in terms of energy efficiency and well-being criteria, as well as in relation to the cultural value of the buildings. The simplified energy calculation method was used to check the present buildings’ energy demands to compare them with retrofitting results. Three retrofitting possibilities were considered: low-cost, current standards, and near-zero energy. The results show that without EU financial aid, which will soon be introduced under the “Renovation Wave” program, such modernization projects will be difficult, making the target of 55% CO2 emission reductions compared to 1990 levels by 2030 impossible.

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“…Lu and Memari [42] presented a comparison of measurement methods for the thermal transmittance of building envelopes. These methods were highly precise.…”

Section: Discussionmentioning

confidence: 99%

Renovation of Modernist Housing Developments in the Pursuit of Modernity for Well-Being and Clean Energy

et al. 2022

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“…In addition, several studies have investigated other developed dynamic analysis methods that could be used to calculate the building envelope elements' (mostly walls) R-values from in situ data, such as the ARX model (also called the black-box model) and the R-C network model (also called grey-box model) [7,43]. Although the use of dynamic models could improve the accuracy of the results, each one has its own advantages and disadvantages; therefore, there is still no consensus on which model would work better in situ measurements [43]. As noted by Bienvenido-Huertas et al [7], more research studies would be needed to clarify the limitations and possibilities of the developed dynamic methods.…”

Section: Heat Flow Meter Sensors For In Situ Measurementsmentioning

confidence: 99%

Review of the Experimental Methods for Evaluation of Windows’ Thermal Transmittance: From Standardized Tests to New Possibilities

2023

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One of the most important parameters that indicate the energy performance of a window system is the thermal transmittance (U-value). Many research studies that deal with numerical methods of determining a window’s U-value have been carried out. However, the possible assumptions and simplifications associated with numerical methods and simulation tools could increase the risk of under- or over-estimation of the U-value. For this reason, several experimental methods for investigating the U-value of windows have been developed to be used either alone or as a supplementary method for validation purposes. This review aims to analyze the main experimental methods for assessing the U-value of windows that have been published by national and international standards or as scientific papers. The analysis criteria include the type of the test in terms of boundary conditions (laboratory or in situ), the part of the window that was tested (only the center of glazing or the entire window), and the data analysis method (steady-state or dynamic). The experimental methods include the heat flow meter (HFM) method, guarded hot plate (GHP) method, hot box (HB) method, infrared thermography (IRT) method, and the so-called rapid U-value metering method. This review has been set out to give insights into the procedure, the necessary equipment units, the required length of time, the accuracy, the advantages and disadvantages, new possibilities, and the gaps associated with each method. In the end, it describes a set of challenges that are designed to provide more comprehensive, realistic, and reliable tests.

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“…A recent literature review has outlined that 93% of the reported U-value assessments show underperformance (O'Hegarty et al, 2021). In this context, on-site U-value assessment is an increasingly relevant process with many recent research and review works been published (Lu and Memari, 2022).…”

Section: Introductionmentioning

confidence: 99%

Surface heat transfer coefficients in building envelopes: Uncertainty levels in experimental methods

Garay-Martinez

Arregi

Lumbreras

2023

Journal of Building Physics

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There are several research methods for the on-site assessment of U-values that aim to avoid the use of surface heat flux measurements and rely on tabulated or empirically developed correlations to define this parameter. This works performs a detailed process to estimate indoor surface heat transfer coefficients based on several experimental campaigns over building walls. Data is filtered out to remove periods with large temperature variations and/or unstable convective conditions due to HVAC. A statistical analysis is conducted, and the outcomes used to test the validity of U-value estimation approaches. The outcomes show that the actual surface heat transfer coefficients are in the range of reference works, but variations in the range of up to 2 W/m2 K are found. Uncertainty levels associated to the estimation of surface heat transfer coefficient are in the range 60% for instantaneous values while this is reduced down to 12%–20% for 8-h averages. Variations and uncertainty levels are higher for low temperature gradient situations, which are considered to be very likely for modern insulation levels. It is concluded that methods seeking to avoid the use of surface heat flux measurements need to develop much deeper knowledge in this field to gain accuracy and reliability.

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Comparison of the Experimental Measurement Methods for Building Envelope Thermal Transmittance

Cited by 12 publications

References 46 publications

Renovation of Modernist Housing Developments in the Pursuit of Modernity for Well-Being and Clean Energy

Renovation of Modernist Housing Developments in the Pursuit of Modernity for Well-Being and Clean Energy

Review of the Experimental Methods for Evaluation of Windows’ Thermal Transmittance: From Standardized Tests to New Possibilities

Surface heat transfer coefficients in building envelopes: Uncertainty levels in experimental methods

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