A perturbation method to estimate building thermal performance

Alzetto, Florent; Meulemans, Johann; Pandraud, Guillaume; Roux, Didier

doi:10.1016/j.crci.2018.09.003

Cited by 13 publications

(12 citation statements)

References 6 publications

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“…The test commences after sunset and finishes before sunrise of the following day (Figure 1b). The principle of the QUB method is based on a single resistance and capacitance model [24] where the building is represented by a global thermal resistance R (the reciprocal of the HTC of the building) and a global capacitance, C (the internal heat capacity) (Figure 1a). Internal and external temperature nodes (T int and T ext respectively) are considered homogeneous and heat exchange between the two nodes occurs through the thermal resistance, R. Temperature evolution is described as a single decaying exponential.…”

Section: The Qub Methodsmentioning

confidence: 99%

“…The thermal response of the building in that case would be the superposition of a number of decaying exponentials. However, it has been shown that after a sufficient amount of time the single RC model provides a good approximation of the building conditions and the model becomes valid [16,17,24]. Based on the single RC model, the energy input, P, is heat lost through the envelope and stored/released by the thermal mass of the fabric (Equation 1):…”

Section: The Qub Methodsmentioning

confidence: 99%

“…This approach led to establishing specific criteria considering the testing conditions with regards to the power input and the internal and external temperature that, when met, allow for a reliable measurement to take place. These criteria have been summed to a dimensionless parameter inherent to the QUB method, the α-parameter, α (e.g., see [16,24] and references therein) (Equation 3).…”

Section: The Qub Methodsmentioning

confidence: 99%

“…It has been demonstrated that the α-parameter has minimum effect on the resulting HTC for values 0.4 ≤ α ≤ 0.7, while for α ≥ 0.7 there is usually an overestimation of the HTC mostly at very short tests [19,21,24]. Hence, meeting this criterion is considered a measure of confidence level for test accuracy.…”

Section: The Qub Methodsmentioning

confidence: 99%

“…Several studies have been previously reported on the performance of the method under actual climatic conditions in different regions of Europe [16,[21][22][23]. A concise description of the different tests and validation experiments is provided by Alzetto et al [24]. These studies demonstrated the applicability of the QUB method to measure the building thermal performance and its suitability to be used as a research tool.…”

Section: Introductionmentioning

confidence: 99%

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Field testing of the QUB method for assessing the thermal performance of dwellings: In situ measurements of the heat transfer coefficient of a circa 1950s detached house in UK

Sougkakis

Meulemans²,

Wood³

et al. 2021

Energy and Buildings

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In this paper the findings from a long-term field study of the thermal performance of a circa 1950s dwelling are presented and discussed. The study aimed at evaluating the robustness of the QUB method in the field under UK climatic conditions. A series of 147 QUB tests were performed during the whole heating period (September 2016 -March 2017) in a detached house located in the University Park campus, University of Nottingham considering two distinct conditions: as-built and with increased airtightness.The QUB method was able to provide consistent and robust estimates of the Heat Transfer Coefficient (HTC) of the whole dwelling with approximately 80% of the results within ± 10% from the mean and more than 95% of the results within ± 15%. The need to treat heat losses occurring through the ground when assessing the thermal performance of buildings through experimental diagnostics methods was highlighted, especially in uninsulated concrete slab floors. The method devised to isolate the ground floor heat losses from the whole building losses resulted in reduced dispersion of the adjusted Heat Transfer Coefficient with a coefficient of variation of 5% and 98% of results within ± 10% from the mean.

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Section: The Qub Methodsmentioning

confidence: 99%

Section: The Qub Methodsmentioning

confidence: 99%

Section: The Qub Methodsmentioning

confidence: 99%

Section: The Qub Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Field testing of the QUB method for assessing the thermal performance of dwellings: In situ measurements of the heat transfer coefficient of a circa 1950s detached house in UK

Sougkakis

Meulemans²,

Wood³

et al. 2021

Energy and Buildings

Self Cite

View full text Add to dashboard Cite

show abstract

Solar Decathlon Europe 2022 – Bauphysikalische Ergebnisse von Demonstrationsgebäuden

Voss¹,

Hansen²,

Kaliga³

et al. 2023

2023 Bauphysik Kalender

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Development of a short duration method to assess the envelope thermal performance of multi-family housings

et al. 2023

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Building energy efficiency is a key factor in reducing CO 2 emissions. For this reason, EU member states have developed thermal regulations to ensure building thermal performance. These results are often based on results achieved with building simulation software during the design stage. However, the actual thermal performance can deviate significantly from the predicted one, and this difference is known as the energy performance gap. Accurate indicators of the actual thermal performance are a valuable tool to guarantee building quality. These indicators, including the heat transfer coefficient (HTC) and the heat loss coefficient (HLC), can be estimated by the application of in situ methods. As multi-family housing and tertiary sector buildings are an important part of the building stock, mature methods to measure their thermal performance are needed. This paper presents a short-duration method for assessing the HTC in large building typologies using a sampling approach. The method was applied in a four-storey building model under different conditions to study the limits of the method and to improve indicator bias and uncertainty. Indicator quality was strongly influenced by the external weather conditions, the temperature variation during the protocol and the heat exchange with the adjacent apartments. Under winter conditions and with stable indoor temperatures, the method had a high accuracy when the protocol was applied for half a day. It is recommended that the protocol be used over two days to improve indicator quality under less favorable test conditions.

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A perturbation method to estimate building thermal performance

Cited by 13 publications

References 6 publications

Field testing of the QUB method for assessing the thermal performance of dwellings: In situ measurements of the heat transfer coefficient of a circa 1950s detached house in UK

Field testing of the QUB method for assessing the thermal performance of dwellings: In situ measurements of the heat transfer coefficient of a circa 1950s detached house in UK

Solar Decathlon Europe 2022 – Bauphysikalische Ergebnisse von Demonstrationsgebäuden

Development of a short duration method to assess the envelope thermal performance of multi-family housings

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