Heat-flow variability of suspended timber ground floors: Implications for in-situ heat-flux measuring

Pelsmakers, S; Fitton, R; Biddulph, P; Swan, W; Croxford, B; Stamp, S; Calboli, FCF; Shipworth, D; Lowe, R; Elwell, CA

Abstract

Reducing space heating energy demand supports the UK’s legislated carbon emission reduction targets and requires the effective characterisation of the UK’s existing housing stock to facilitate retrofitting decision-making. Approximately 6.6 million UK dwellings pre-date 1919 and are predominantly of suspended timber ground floor construction, the thermal performance of which has not been extensively investigated. This paper examines suspended timber ground floor heat-flow by presenting high resolution in-situ heat-flux measurements undertaken in a case study house at 15 point locations on the floor. The results highlight significant variability in observed heat-flow: point U-values range from 0.56 ± 0.05 to 1.18 ± 0.11 Wm−2 K−1. This highlights that observing only a few measurements is unlikely to be representative of the whole floor heat-flow and the extrapolation from such point values to whole floor U-value estimates could lead to its over- or under- estimation. Floor U-value models appear to underestimate the actual measured floor U-value in this case study. This paper highlights the care with which in-situ heat-flux measuring must be undertaken to enable comparison with models, literature and between studies and the findings support the unique, high-resolution in-situ monitoring methodology used in this study for further research in this area.

Citation

Pelsmakers, S., Fitton, R., Biddulph, P., Swan, W., Croxford, B., Stamp, S., …Elwell, C. (2017). Heat-flow variability of suspended timber ground floors: Implications for in-situ heat-flux measuring. Energy and Buildings, 138, 396-405. https://doi.org/10.1016/j.enbuild.2016.12.051

• Journal Article Type: Article
• Acceptance Date: Dec 16, 2016
• Online Publication Date: Dec 24, 2016
• Publication Date: Mar 1, 2017
• Deposit Date: Jan 3, 2017
• Publicly Available Date: Dec 24, 2017
• Journal: Energy and Buildings
• Print ISSN: 0378-7788
• Publisher: Elsevier
• Volume: 138
• Pages: 396-405
• DOI: https://doi.org/10.1016/j.enbuild.2016.12.051
• Publisher URL: http://dx.doi.org/10.1016/j.enbuild.2016.12.051