Ventilation strategy, energy use and CO2 emissions in dwellings -a theoretical approach

Lowe, RJ

doi:10.1177/014362440002100306

Cited by 14 publications

(19 citation statements)

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“…Similarly, raising environmental awareness in households demands a more transparent and clearly justified explanation of energy consumption resulting from MV operation so that households have a better understanding of why they should change their practices or whether they need to complain about their MV systems not working well. Existing justifications for installing MV systems (Lowe, 2000) must be questioned when wider than assumed temperature comfort ranges are accepted by the inhabitants according to the results of this study. Two specific factors hampering the occupants' use of their MV as designed have emerged from this study: those specifically related to the industry and those related to the user transition period towards low-energy buildings and the permanent adjustments that are required to the design of the system as a result of this transition during the initial year of occupancy.…”

Section: Discussionmentioning

confidence: 99%

Mechanical ventilation in housing: understanding in-use issues

Baborska-Narożny¹,

Stevenson²

2017

Proceedings of the Institution of Civil Engineers - Engineering

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Continuous mechanical ventilation (MV) in housing can in theory secure recommended air change levels without depending on control by inhabitants or on uncontrolled air leaks. Numerous in-use issues related to continuous MV systems have, however, been identified through field studies. The gap between design intention and actual performance and use of continuous MV should be narrowed as far as possible to reduce energy use and increase the inhabitants' health. This paper proposes a process diagram linking the emergence of ventilation practises with factors related to both the occupant (tacit knowledge, learning and needs) and the dwelling (design and procurement). Steps of the process are identified where the performance gap in relation to the continuous MV may gradually build up and lead to MV being ignored in a domestic context -that is, failing to secure the necessary maintenance or even switching the system off permanently. The diagram is based on findings of previous studies as well as results of a 1-year-long in-depth building performance evaluation of 40 households in two UK developments.

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Section: Discussionmentioning

confidence: 99%

Mechanical ventilation in housing: understanding in-use issues

Baborska-Narożny¹,

Stevenson²

2017

Proceedings of the Institution of Civil Engineers - Engineering

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“…DOMVENT3D, a model of infiltration and exfiltration built for Matlab considers the walls as porous media with a linear model of pressure distribution. [74][75][76] The stack and wind pressure diagrams are considered additive creating the possibility for the integration of the overall equation of infiltration along of the wall. Despite their actual complexities and different numerical and programming particularities, the comparison of the results of analysis platforms like CONTAM and DOMVENT3D provides differences in results that are less than 1%.…”

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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“…This article applies DOMVENT3D, a model of infiltration and exfiltration through any number of façades developed initially by Lowe [23] on the basis of a theoretical formulation by Lyberg [24], and subsequently extended by Jones et al [25]. It assumes two things about those façades: all are uniformly porous; and the pressure distribution over a vertical surface is linear.…”

Section: Modelling Infiltration and Exfiltration Heat Lossmentioning

confidence: 99%

Assessing uncertainty in housing stock infiltration rates and associated heat loss: English and UK case studies

Jones

Das

Chalabi

et al. 2015

Building and Environment

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Strategies to reduce domestic heating loads by minimizing the infiltration of cold air through adventitious openings located in the thermal envelopes of houses are highlighted by the building codes of many countries. Consequent reductions of energy demand and CO 2 e emission are often unquantified by empirical evidence. Instead, a mean heating season infiltration rate is commonly inferred from an air leakage rate using a simple ratio scaled to account for the physical and environmental properties of a dwelling. The scaling does not take account of the permeability of party walls in conjoined dwellings and so cannot differentiate between the infiltration of unconditioned ambient air that requires heating, and conditioned air from adjacent dwellings that does not.A stochastic method is presented that applies a theoretical model of adventitious infiltration to predict distributions of mean infiltration rates and the associated total heat loss in any stock of dwellings during heating hours. The method is applied to the English and UK housing stocks and provides probability distribution functions of stock infiltration rates and total heat loss during the heating season for two extremes of party wall permeability. The distributions predict that up to 79% of the current English stock could require additional purpose-provided ventilation to limit negative health consequences. National models predict that fewer dwellings are under-ventilated. The distributions are also used to predict that infiltration is responsible for 3-5% of total UK energy demand, 11-15% of UK housing stock energy demand, and 10-14% of UK housing stock carbon emissions.3 HIGHLIGHTS  Heating season infiltration and heat loss distributions for English housing stock. Up to 79% of English dwellings may be under ventilated. Exfiltration estimated to be responsible for 3-5% of total UK energy demand. Exfiltration estimated to be responsible for 11-15% UK housing stock energy demand. Exfiltration estimated to be responsible for 10-14% UK housing stock CO 2 emissions.

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Ventilation strategy, energy use and CO2 emissions in dwellings -a theoretical approach

Cited by 14 publications

References 1 publication

Mechanical ventilation in housing: understanding in-use issues

Mechanical ventilation in housing: understanding in-use issues

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

Assessing uncertainty in housing stock infiltration rates and associated heat loss: English and UK case studies

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