AC pressurisation: Fourier analysis and the effect of compressibility of air

Dewsbury, Jonathan

doi:10.1177/014362449601700203

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…Although the AC method was quicker to set up and implement, it was more difficult to interpret the results compared to the steady method used alongside. Moreover, the measurement is limited to certain frequency due to the impact of environmental noise [ 88 , 89 ] and certain opening size as further increase in the opening size doesn't affect the test results. Therefore, AC method has not been widely used in the field.…”

Section: Steady Pressurisation Methods and Alternativesmentioning

confidence: 99%

A practical review of alternatives to the steady pressurisation method for determining building airtightness

Zheng

Cooper

Gillott

et al. 2020

Renewable and Sustainable Energy Reviews

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As an important indicator of construction quality and envelope integrity of buildings, airtightness is responsible for a considerable amount of energy losses associated with infiltration. It is crucial to understand building airtightness during construction and retrofitting to achieve a suitable envelope airtightness which is essential for obtaining a desirable building energy efficiency, durability and indoor environment. As a convenient means of measurement, the current steady pressurisation method has long been accepted as a standard testing method for measuring building airtightness. It offers an intuitive and robust approach for measuring building airtightness and performing building diagnostics. However, it also has some shortcomings that are mainly related to its high pressure measurement, requirement for skilful operation, long test duration and change to the building envelope. Efforts have been made by manufacturers and researchers to further improve its accuracy and practicality with much progress achieved. Work has also been done to develop alternative methods that can overcome some of the issues. This paper provides a practical review on the incumbent methodology and efforts that have been made over the past decades in research and development of other methods to achieve a similar purpose. It compares them in relation to aspects that are considered important in achieving an accurate, quick and practical measurement of building airtightness and the finding shows other methods such as acoustic and unsteady technique have their own advantages over the steady pressurisation method but also add some of their own restrictions, which therefore makes them suited for different applications.

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Section: Steady Pressurisation Methods and Alternativesmentioning

confidence: 99%

A practical review of alternatives to the steady pressurisation method for determining building airtightness

Zheng

Cooper

Gillott

et al. 2020

Renewable and Sustainable Energy Reviews

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“…Further developments have centered around the diversification of the measuring equipment [52][53][54][55][56][57][58][59] and the implementation of Fourier analysis on this kind of signals. 60,61 Several measurement procedures are detailed in Cooper et al 56 and Cooper and Etheridge. 62 This study selects some mathematical procedures from these techniques as we ascertained that there are closed similarities between the natural oscillation of the atmospheric pressure and the induced harmonics of pressure.…”

Section: Previous Approaches To Air Exchange In Transient Conditionsmentioning

confidence: 99%

“…Further developments have centered around the diversification of the measuring equipment 52–59 and the implementation of Fourier analysis on this kind of signals. 60,61 Several measurement procedures are detailed in Cooper et al. 56 and Cooper and Etheridge.…”

Section: Previous Approaches To Air Exchange In Transient Conditionsmentioning

confidence: 99%

Modeling air leakage in buildings caused by the cyclic variation of the atmospheric pressure

Pătraşcu

Baracu

Badescu

et al. 2018

Building Services Engineering Research and Technology

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This article considers a new type of air infiltration through building envelopes caused by the barometric pressure variation. This process is independent from wind action or stack effect. A new building-atmosphere differential equation of air exchange is established. Based on the solution of the differential equation of air exchange, we propose the notion of pressure equilibration time 50 that characterizes the dynamic response of the building. Furthermore, experimental climatic data were processed using Fourier analysis methods in order to build an identification model based on the regular harmonics of external pressure oscillation. The barometric pressure reconstructed in its parameterized form was introduced in the differential equation of air exchange as a term that models the dynamics of the external action. The analytic solution of the differential equation of air exchange demonstrates that the indoor-outdoor pressure difference is insignificant at less than 10 À3 Pa for any harmonic of the external pressure variation. At the same time, it is concluded that the airtightness of the envelope has little influence on the process, as the indoor-outdoor pressure equilibration is almost instantaneous in a continuous regime of variation. The described mechanism of air infiltration explains the alternation of infiltration and exfiltration of air in buildings. For this, a mass balance of air exchange for the specific ranges of time is performed. We prove that the barometric pressure variation has an effect that accounts for 3.19% of the total quantity of air exchanged. The advances provided by this paper constitute a useful instrument for further studies concerning the stack effect in thermal dynamic conditions. Practical application: The paper proposes a novel methodology of determining the air exchange building-environment by considering a new component of infiltration and its cyclic variation: the barometric pressure. A new mechanism of natural air infiltration is determined and modeled and it should be added to the existing ones: wind action and stack effect. A complete methodology of analysis and extraction of

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“…Measurements are based on steady pressure, creating a sinusoidal volume change to the building by a reciprocating piston (Figure 4). The physical principles were first stated (Sherman, Grimsrud, & Sonderegger, 1979), and then further developed (Dewsbury, 1996;Watanabe, Kobayashi, Utsumi, & Miyagi, 1999). However, due to accuracy and interpretation issues, and reported limitations, the AC pressurisation method is not widely used at present.…”

Section: Alternating Pressurisation Methodsmentioning

confidence: 99%

Airtightness performance of the building envelope of dwellings in Spain. Characterisation and energy impact of air infiltration

Casado¹

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Only after the oil crisis in the 1970s has there been an undeniable growth in the level of interest in reducing the use of fossil fuels. In this regard, the countries of the European Union predict a sustainable, competitive and decarbonised energy system by 2050. For that purpose, it is crucial to address the energy efficiency of buildings, which are responsible for a significant percentage of energy consumption, and, therefore, greenhouse gas emissions. The potential seems obvious, considering that, according to the European Commission, 75% of the buildings in Europe are energy inefficient.In this context, uncontrolled airflow through the building envelope, or air infiltration, is a phenomenon that involves energy loss since it needs to be conditioned at the interior comfort conditions. Air infiltration is also related to the ventilation of buildings and, thus, has an impact on indoor air quality. In this sense, a relationship is established between air infiltration, energy impact and ventilation. Since airtightness is the main characteristic of the envelope that determines air infiltration, its study is essential to understand the performance of the building envelope.However, this issue has not been addressed in depth in most countries with temperate climates, and, specifically, in Spain, given the traditional dependence of air renewal on air infiltration. Currently, the implementation of controlled ventilation systems guarantees adequate indoor air quality in residential buildings. Therefore, air infiltration is no longer necessary as an air renewal source and, consequently, its reduction is a priority to achieve nearly zero-energy buildings (nZEB). In this sense, the airtightness characterisation of the envelope of existing buildings is essential to prioritise efforts and determine strategies for the renovation of the existing building stock according to the decarbonisation objectives which have been set at a national and international level.

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AC pressurisation: Fourier analysis and the effect of compressibility of air

Cited by 4 publications

References 3 publications

A practical review of alternatives to the steady pressurisation method for determining building airtightness

A practical review of alternatives to the steady pressurisation method for determining building airtightness

Modeling air leakage in buildings caused by the cyclic variation of the atmospheric pressure

Airtightness performance of the building envelope of dwellings in Spain. Characterisation and energy impact of air infiltration

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