Transition from n<sub>50</sub> to actual air exchange dependent on climatic conditions

Kisilewicz, Tomasz; Nowak-Dzieszko, Katarzyna; Rojewska-Warchał, Małgorzata

doi:10.1051/matecconf/201928202101

Cited by 1 publication

(4 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Infiltration is expected to be lower in summer than winter because the variable drivers of infiltration, i.e. the wind speed and indoor-outdoor temperature difference (Labat et al , 2013), will also be lower (Binamu and Lindberg, 2002; Hong and Kim, 2016; Kisilewicz et al , 2019). Infiltration may also be lower in summer due to seasonal variation in building envelope air permeability which can be 20–40% lower in summer due to building materials expanding and contracting with seasonal changes in humidity (Warren and Webb, 1980b; Persily, 1983; Kim and Shaw, 1986; Bassett, 1992; Bracke et al , 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Although infiltration estimation methods were empirically validated during and soon after their development (e.g. Liddament and Allen, 1983), more recent evidence has questioned the ability of some infiltration estimation methods to accurately estimate infiltration rate, with calls for more research (Keig et al , 2016; Johnston and Stafford, 2017; Johnston et al , 2017; Johnston and Miles-Shenton, 2018; Kisilewicz et al , 2019; Vega Pasos et al . 2019, 2020; Mun et al , 2021).…”

Section: Introductionmentioning

confidence: 99%

“…The prior research tends to focus on wintertime infiltration due to legitimate concerns about wintertime heating demand (Keig et al , 2016; Johnston and Stafford, 2017; Johnston et al , 2017; Johnston and Miles-Shenton, 2018; Kisilewicz et al , 2019; Vega Pasos et al . 2019, 2020; Mun et al , 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Infiltration may also be lower in summer due to seasonal variation in building envelope air permeability which can be 20–40% lower in summer due to building materials expanding and contracting with seasonal changes in humidity (Warren and Webb, 1980b; Persily, 1983; Kim and Shaw, 1986; Bassett, 1992; Bracke et al , 2016). However, the estimates of infiltration rate may be least accurate in the summer season, with one relevant study showing that the difference between measured and estimated infiltration rates (Sherman Simplified model) were greater in summer and smaller in the winter (Kisilewicz et al , 2019). Because of growing concerns about summertime overheating, and to redress the wintertime focus of virtually all infiltration studies, this work measured infiltration rates in the summer.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluating methods for estimating whole house air infiltration rates in summer: implications for overheating and indoor air quality

Roberts

Allinson

Lomas

2021

IJBPA

View full text Add to dashboard Cite

PurposeAccurate values for infiltration rate are important to reliably estimate heat losses from buildings. Infiltration rate is rarely measured directly, and instead is usually estimated using algorithms or data from fan pressurisation tests. However, there is growing evidence that the commonly used methods for estimating infiltration rate are inaccurate in UK dwellings. Furthermore, most prior research was conducted during the winter season or relies on single measurements in each dwelling. Infiltration rates also affect the likelihood and severity of summertime overheating. The purpose of this work is to measure infiltration rates in summer, to compare this to different infiltration estimation methods, and to quantify the differences.Design/methodology/approachFifteen whole house tracer gas tests were undertaken in the same test house during spring and summer to measure the whole building infiltration rate. Eleven infiltration estimation methods were used to predict infiltration rate, and these were compared to the measured values. Most, but not all, infiltration estimation methods relied on data from fan pressurisation (blower door) tests. A further four tracer gas tests were also done with trickle vents open to allow for comment on indoor air quality, but not compared to infiltration estimation methods.FindingsThe eleven estimation methods predicted infiltration rates between 64 and 208% higher than measured. The ASHRAE Enhanced derived infiltration rate (0.41 ach) was closest to the measured value of 0.25 ach, but still significantly different. The infiltration rate predicted by the “divide-by-20” rule of thumb, which is commonly used in the UK, was second furthest from the measured value at 0.73 ach. Indoor air quality is likely to be unsatisfactory in summer when windows are closed, even if trickle vents are open.Practical implicationsThe findings have implications for those using dynamic thermal modelling to predict summertime overheating who, in the absence of a directly measured value for infiltration rate (i.e. by tracer gas), currently commonly use infiltration estimation methods such as the “divide-by-20” rule. Therefore, infiltration may be overestimated resulting in overheating risk and indoor air quality being incorrectly predicted.Originality/valueDirect measurement of air infiltration rate is rare, especially multiple tests in a single home. Past measurements have invariably focused on the winter heating season. This work is original in that the tracer gas technique used to measure infiltration rate many times in a single dwelling during the summer. This work is also original in that it quantifies both the infiltration rate and its variability, and compares these to values produced by eleven infiltration estimation methods.

show abstract