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Clifford A. Elwell
UCL, Energy Institute, Central House, 14 Upper Woburn Place, London, United Kingdom

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Conference paper
Published: 30 June 2020 in E3S Web of Conferences
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This paper presents sensitivity and uncertainty analyses on a DELPHIN model, which is representative of a case study wall in real climatic conditions. Results of the Differential Sensitivity Analysis (DSA) show properties governing liquid water transported into, through and stored in the wall impact most on moisture accumulation, affecting relative humidity (RH) outputs by 10 – 35% at three different locations in the wall. Parameters affecting vapour transport into the room also influence RH outputs at the inner location, but less than rain amount and rain exchange coefficient. A probabilistic uncertainty study is then used to explore key material functions, parameterised as four sets of co-ordinates and varied randomly. The correlation between the parameter inputs and the resulting change in RH is assessed. There are some surprising divergences from the DSA, including the significance of moisture storage in the plaster layer in the presence of liquid. Low correlation coefficients suggest numbers of variables could be reduced to further clarify the effects of these parameters, and interesting questions are raised on the parameterisation of material functions to represent the uncertainty in the characterisation of real walls.

ACS Style

Naomi Grint; Valentina Marincioni; Clifford Elwell. Sensitivity and Uncertainty analyses on a DELPHIN model: the impact of material properties on moisture in a solid brick wall. E3S Web of Conferences 2020, 172, 04006 .

AMA Style

Naomi Grint, Valentina Marincioni, Clifford Elwell. Sensitivity and Uncertainty analyses on a DELPHIN model: the impact of material properties on moisture in a solid brick wall. E3S Web of Conferences. 2020; 172 ():04006.

Chicago/Turabian Style

Naomi Grint; Valentina Marincioni; Clifford Elwell. 2020. "Sensitivity and Uncertainty analyses on a DELPHIN model: the impact of material properties on moisture in a solid brick wall." E3S Web of Conferences 172, no. : 04006.

Conference paper
Published: 30 June 2020 in E3S Web of Conferences
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This work addresses the need for long-term, high-resolution, in-situ datasets by providing in-wall humidity and temperature data from three walls of in-use office buildings over three to four years, two of which were insulated during this period. Temperature and humidity sensors were inserted diagonally into three locations within the thick brick walls, and the holes were carefully packed with dry brick dust. Surface, ambient and interstitial measurements were also recorded, as were additional climatic data during 18 months at one wall, and in-wall moisture content using resistance pins for 18 months in another. This dataset is unique due to the combination of temporal length and resolution, spatial detail, as well as the availability of control data from both before and after insulation and the use of real climatic conditions on both sides of the walls. The experiment was designed to produce data to facilitate parameter estimation by inverse analysis. By using these estimated parameters, or by taking material property measurements, it would also be useful for validating and calibrating hygrothermal models, and by using plausible ranges for parameters it is useful for exploring model performance, such as through sensitivity analyses.

ACS Style

Naomi Grint; Clifford Elwell. Moisture in walls before and after internal wall insulation: a long-term in-situ dataset. E3S Web of Conferences 2020, 172, 01005 .

AMA Style

Naomi Grint, Clifford Elwell. Moisture in walls before and after internal wall insulation: a long-term in-situ dataset. E3S Web of Conferences. 2020; 172 ():01005.

Chicago/Turabian Style

Naomi Grint; Clifford Elwell. 2020. "Moisture in walls before and after internal wall insulation: a long-term in-situ dataset." E3S Web of Conferences 172, no. : 01005.

Research article
Published: 22 May 2020 in Building Services Engineering Research and Technology
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Gas boilers dominate domestic heating in the UK, and significant efficiency improvements have been associated with condensing boilers. However, the potential remains for further efficiency improvement by refining the control, system specification and installation in real dwellings. Dynamic building simulation modelling, including detailed heating system componentry, enables a deeper analysis of boiler underperformance. This paper explores the link between the space heat oversizing of boilers and on/off cycling using dynamic simulation, and their subsequent effect on boiler efficiency and internal temperatures. At plant size ratio (PSR) 8.5 daily cycles numbered over 50, similar to median levels seen in real homes. Simulations show that typical oversizing (PSR >3) significantly increases cycling behaviour and brings an efficiency penalty of 6–9%. There is a clear link between raising PSR, increased cycling and an associated decreased efficiency; however, in the UK, boilers are regularly oversized with respect to space heating, especially combination boilers to cover peak hot water demand. Current legislation and labelling (ErP and SAP) overlook PSR as a determinant of system efficiency, failing to incentivise appropriate sizing. Reducing boiler oversizing through addressing installation practices and certification has the potential to significantly improve efficiency at low cost, decreasing associated carbon emissions. Practical application: This research provides the basis for a practical and cost effective means of assessing the potential for underperformance of boiler heating systems at the point of installation or refurbishment. By assessing the oversizing of the boiler with respect to space heating, unnecessary cycling and the associated efficiency penalty can be avoided. Plant size ratio, as an indicator of cycling potential, can be implemented in energy performance certificates (EPCs), through the standard assessment procedure (SAP), using existing data. The potential for real carbon savings in the existing boiler stock is considerable, and the findings have wider implications for next generation heating systems.

ACS Style

George Bennett; Clifford Elwell. Effect of boiler oversizing on efficiency: a dynamic simulation study. Building Services Engineering Research and Technology 2020, 41, 709 -726.

AMA Style

George Bennett, Clifford Elwell. Effect of boiler oversizing on efficiency: a dynamic simulation study. Building Services Engineering Research and Technology. 2020; 41 (6):709-726.

Chicago/Turabian Style

George Bennett; Clifford Elwell. 2020. "Effect of boiler oversizing on efficiency: a dynamic simulation study." Building Services Engineering Research and Technology 41, no. 6: 709-726.

Journal article
Published: 02 December 2019 in Energy and Buildings
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The accurate determination of the in-use heat transfer coefficient (HTC) of a dwelling can support efficiency improvements and understanding of energy costs, potentially addressing the performance gap. This paper introduces a dynamic grey-box framework combining Bayesian methods and lumped thermal capacitance models for the estimation of the performance of in-use buildings. It focuses on methods to account for solar gains, a significant contributor to the heat transfer. Six simple first-order lumped models of occupied homes are presented, which explicitly include gains from solar radiation with varying complexity. Specifically, the models use solar radiation as a single heat input, divided by façade according to the angle of the sun, and including diffuse radiation. Two case study houses in the UK, monitored over two different seasons, were used to illustrate the models’ performance. Bayesian model comparison was used, in conjunction with other methods, to determine the most suitable model for each sub-dataset analysed; this indicates that the most appropriate model is both season and case-study dependent, highlighting the importance of local topography and weather experienced. For each case study, the models selected provided HTC estimates within 15% of each other, including during the summer, using only 5-10 days of data. Such techniques have the potential to estimate the thermal performance of dwellings year-round, with minimum disturbance to the occupants and could be developed to improve quality assurance processes for new build and retrofit, identify opportunities for targeted retrofit, and close the performance gap. (Declarations of interest: none.)

ACS Style

Frances P. Hollick; Virginia Gori; Clifford A. Elwell. Thermal performance of occupied homes: A dynamic grey-box method accounting for solar gains. Energy and Buildings 2019, 208, 109669 .

AMA Style

Frances P. Hollick, Virginia Gori, Clifford A. Elwell. Thermal performance of occupied homes: A dynamic grey-box method accounting for solar gains. Energy and Buildings. 2019; 208 ():109669.

Chicago/Turabian Style

Frances P. Hollick; Virginia Gori; Clifford A. Elwell. 2019. "Thermal performance of occupied homes: A dynamic grey-box method accounting for solar gains." Energy and Buildings 208, no. : 109669.

Journal article
Published: 13 September 2019 in Energies
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Domestic Energy Performance Certificates (EPCs) are used in the UK to provide energy efficiency ratings for use in policy and investment decisions on individual dwellings and at a stock level. There is evidence that the process of creating an EPC introduces measurement error such that repeat assessments of the same property give different ratings, compromising their reliability. This study presents a novel error analysis to estimate the size of this effect, using repeated EPC assessments of 1.6 million existing dwellings in England and Wales. A statistical model of how measurement error contributes to variation between repeated measurements is set out, and exploratory data analysis is used to decide how to apply this model to the available data. The results predict that the one standard deviation measurement error decreases with EPC rating, from around ± 8.0 EPC points on a rating of 35 to ±2.4 on a rating of 85. This predicted error is higher than the limit recommended in UK guidance except in very efficient buildings; it can also result in dwellings being rated in the wrong EPC band, for example it was estimated that 24% of band D homes are rated as band C.

ACS Style

Jenny Crawley; Phillip Biddulph; Paul J. Northrop; Jez Wingfield; Tadj Oreszczyn; Cliff Elwell. Quantifying the Measurement Error on England and Wales EPC Ratings. Energies 2019, 12, 3523 .

AMA Style

Jenny Crawley, Phillip Biddulph, Paul J. Northrop, Jez Wingfield, Tadj Oreszczyn, Cliff Elwell. Quantifying the Measurement Error on England and Wales EPC Ratings. Energies. 2019; 12 (18):3523.

Chicago/Turabian Style

Jenny Crawley; Phillip Biddulph; Paul J. Northrop; Jez Wingfield; Tadj Oreszczyn; Cliff Elwell. 2019. "Quantifying the Measurement Error on England and Wales EPC Ratings." Energies 12, no. 18: 3523.

Journal article
Published: 12 August 2019 in International Journal of Building Pathology and Adaptation
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PurposeMillions of properties have suspended timber ground floors globally, with around ten million in the UK alone. However, it is unknown what the floor void conditions are, nor the effect of insulating such floors. Upgrading floors changes the void conditions, which might increase or decrease moisture build-up and mould and fungal growth. The purpose of this paper is to provide a review of the current global evidence and present the results ofin situmonitoring of 15 UK floor voids.Design/methodology/approachAn extensive literature review on the moisture behaviour in both uninsulated and insulated suspended timber crawl spaces is supplemented with primary data of a monitoring campaign during different periods between 2012 and 2015. Air temperature and relative humidity sensors were placed in different floor void locations. Where possible, crawl spaces were visually inspected.FindingsComparison of void conditions to mould growth thresholds highlights that a large number of monitored floor voids might exceed the critical ranges for mould growth, leading to potential occupant health impacts if mould spores transfer into living spaces above. A direct comparison could not be made between insulated and uninsulated floors in the sample due to non-random sampling and because the insulated floors included historically damp floors. The study also highlighted that long-term monitoring over all seasons and high-resolution monitoring and inspection are required; conditions in one location are not representative of conditions in other locations.Originality/valueThis study presents the largest UK sample of monitored floors, evaluated using a review of current evidence and comparison with literature thresholds.

ACS Style

Sofie Pelsmakers; Evy Vereecken; Miimu Airaksinen; Clifford Elwell. Void conditions and potential for mould growth in insulated and uninsulated suspended timber ground floors. International Journal of Building Pathology and Adaptation 2019, 37, 395 -425.

AMA Style

Sofie Pelsmakers, Evy Vereecken, Miimu Airaksinen, Clifford Elwell. Void conditions and potential for mould growth in insulated and uninsulated suspended timber ground floors. International Journal of Building Pathology and Adaptation. 2019; 37 (4):395-425.

Chicago/Turabian Style

Sofie Pelsmakers; Evy Vereecken; Miimu Airaksinen; Clifford Elwell. 2019. "Void conditions and potential for mould growth in insulated and uninsulated suspended timber ground floors." International Journal of Building Pathology and Adaptation 37, no. 4: 395-425.

Journal article
Published: 01 July 2019 in International Journal of Building Pathology and Adaptation
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Purpose The purpose of this paper is to investigate the distribution of dwelling airtightness test results for a developer, between 2007 and 2011. The changes in airtightness test results over time are discussed, and links between the airtightness test results and the construction technique are investigated. Design/methodology/approach A data set of airtightness test results was statistically analysed by applying probabilistic model of the distribution and using Bayesian parameter estimation techniques. Findings The inferred background distributions, those estimated to describe dwelling performance before secondary sealing, suggest an improvement in airtightness between 2008 and 2011, the mode decreases from 5.46±0.09 m3/m2h to 4.12±0.07 m3/m2h with a corresponding shift in practice towards a more target-driven approach. The most airtight dwellings are constructed from reinforced concrete frame, followed by “traditional” (dry lined masonry), timber frame and lightweight steel frame. Research limitations/implications This study is limited by the size of the available data set (901 dwellings), and by the fact that the data set contains a larger proportion of flats to houses; however, the metadata has enabled the exploration of the link between construction practices and airtightness. Practical implications Developers need better guidance surrounding how to meet more stringent airtightness requirements through improvements to the primary air barrier, with incentives and support to deliver changes in practice. Furthermore, if a large number of dwellings undergo secondary sealing, this may have implications for the long-term efficiency of the dwelling stock. Originality/value This analysis investigates two issues that have not previously been studied on a significant number of dwellings: the changes to the distribution of airtightness results over time and the link between construction methods and airtightness.

ACS Style

Minnie M.A. Ashdown; Jenny Crawley; Phillip Biddulph; Jez Wingfield; Robert Lowe; Clifford Elwell. Characterising the airtightness of dwellings. International Journal of Building Pathology and Adaptation 2019, 38, 89 -106.

AMA Style

Minnie M.A. Ashdown, Jenny Crawley, Phillip Biddulph, Jez Wingfield, Robert Lowe, Clifford Elwell. Characterising the airtightness of dwellings. International Journal of Building Pathology and Adaptation. 2019; 38 (1):89-106.

Chicago/Turabian Style

Minnie M.A. Ashdown; Jenny Crawley; Phillip Biddulph; Jez Wingfield; Robert Lowe; Clifford Elwell. 2019. "Characterising the airtightness of dwellings." International Journal of Building Pathology and Adaptation 38, no. 1: 89-106.

Journal article
Published: 08 May 2019 in International Journal of Building Pathology and Adaptation
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Purpose Compulsory airtightness testing was introduced for new dwellings in England and Wales in 2006 and in Scotland in 2010 to ensure that they are constructed according to design air permeability targets. These targets are set to limit heat loss through air infiltration. Previous work examining the large Air Tightness Testing and Measurement Association (ATTMA) data set of UK airtightness test data suggested that, in a proportion of dwellings, the targets were being met by post-completion sealing as opposed to airtight construction, but did not quantify the prevalence of this practice. The paper aims to discuss this issue. Design/methodology/approach In this paper, the distribution of as-built airtightness and the proportion of dwellings undergoing post-completion sealing are estimated from the ATTMA data set covering 2015–2016. This is carried out by Bayesian statistical modelling, using the data set of recorded test results and a modelled representation of the testing process. Findings This analysis finds the mode of the as-built distribution of air permeability as 4.38 ± 0.01 m3/m2h. It predicts that 39 per cent of dwellings aiming for one of the five most common design targets have sealing interventions at the point of pressure testing to meet their target. The as-built distribution of the ATTMA data is compared to airtightness test data obtained from just before compulsory testing was introduced, showing an improvement in the modal air permeability of 3.6 m3/m2h since testing became mandatory. Originality/value This paper has investigated the available data beyond simply what is reported, to estimate what the real levels of airtightness in the UK new build stock may be.

ACS Style

Jenny Crawley; Phillip Biddulph; Jez Wingfield; Minnie Ashdown; Robert Lowe; Clifford Elwell. Inferring the as-built air permeability of new UK dwellings. International Journal of Building Pathology and Adaptation 2019, 38, 3 -19.

AMA Style

Jenny Crawley, Phillip Biddulph, Jez Wingfield, Minnie Ashdown, Robert Lowe, Clifford Elwell. Inferring the as-built air permeability of new UK dwellings. International Journal of Building Pathology and Adaptation. 2019; 38 (1):3-19.

Chicago/Turabian Style

Jenny Crawley; Phillip Biddulph; Jez Wingfield; Minnie Ashdown; Robert Lowe; Clifford Elwell. 2019. "Inferring the as-built air permeability of new UK dwellings." International Journal of Building Pathology and Adaptation 38, no. 1: 3-19.

Journal article
Published: 22 December 2018 in Building Services Engineering Research and Technology
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The UK’s Air Tightness Testing and Measurement Association competent persons scheme collects pressure test data and metadata from the majority of new build dwellings in the UK. This article uses the dataset to investigate the importance of the ventilation strategy in airtightness design and construction. Design and measured airtightness were tested for association with declared ventilation strategy. It was found that ventilation strategy makes a statistically significant difference to airtightness; however, this difference is too small to be practically relevant. Properties with mechanical ventilation and heat recovery (MVHR) were shown to have a mean designed air permeability only 0.46 m3/m2h lower than naturally ventilated dwellings. Seventy-three per cent of homes with MVHR have design airtightness greater than or equal to 5 m3/m2h and 17% of naturally ventilated dwellings have design airtightness less than 5 m3/m2h. We discuss how current design is not maximising the CO2, cost and air quality benefit of each ventilation strategy. A new approach to regulatory compliance is proposed, which explicitly links the designed airtightness and chosen ventilation system. It is suggested that compliance could then be achieved using a set of airtightness ranges linked to appropriate ventilation strategies. This could be expected to result in reduced energy consumption and carbon emissions for new build homes compared to the current approach and would also potentially lead to better outcomes for occupants in terms of indoor air quality. Practical application: Analysis of a large database of the airtightness of new UK dwellings found that ventilation strategy makes very little difference to airtightness design. For dwellings with MVHR, the results suggest that infiltration levels are too high to maximise the energy savings; for naturally ventilated homes, there may be air quality issues. Coupling airtightness design and ventilation strategy can reduce a dwelling’s energy demand and can support achieving the required energy performance rating.

ACS Style

Jenny Crawley; Jez Wingfield; Clifford Elwell. The relationship between airtightness and ventilation in new UK dwellings. Building Services Engineering Research and Technology 2018, 40, 274 -289.

AMA Style

Jenny Crawley, Jez Wingfield, Clifford Elwell. The relationship between airtightness and ventilation in new UK dwellings. Building Services Engineering Research and Technology. 2018; 40 (3):274-289.

Chicago/Turabian Style

Jenny Crawley; Jez Wingfield; Clifford Elwell. 2018. "The relationship between airtightness and ventilation in new UK dwellings." Building Services Engineering Research and Technology 40, no. 3: 274-289.

Correction
Published: 06 September 2018 in Energies
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The authors wish to make the following corrections to their paper [1]:

ACS Style

Virginia Gori; Phillip Biddulph; Clifford A. Elwell. Correction: Gori, V.; Biddulph, P.; Elwell, C.A. A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error. Energies 2018, 11, 802. Energies 2018, 11, 2353 .

AMA Style

Virginia Gori, Phillip Biddulph, Clifford A. Elwell. Correction: Gori, V.; Biddulph, P.; Elwell, C.A. A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error. Energies 2018, 11, 802. Energies. 2018; 11 (9):2353.

Chicago/Turabian Style

Virginia Gori; Phillip Biddulph; Clifford A. Elwell. 2018. "Correction: Gori, V.; Biddulph, P.; Elwell, C.A. A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error. Energies 2018, 11, 802." Energies 11, no. 9: 2353.

Research article
Published: 20 August 2018 in Building Services Engineering Research and Technology
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Residential space and water heating account for 23% of UK final energy demand and combination gas boilers are the dominant technology. Performance gap issues in gas boiler systems have been reported, with previous studies unable to isolate or quantify root causes for performance issues, hampered by indirect and coarse measurement methods. Utilising high-frequency data, through state-of-the-art boiler diagnostics from 221 UK combination boilers, assumptions in efficiency standards are challenged. Total heating energy consumption and number of hot water tappings are in line with national expectations but the observed cycling behaviour of boilers gives cause for concern due to links with lower performance and higher emissions. Most combi-boilers appear oversized for space heating and despite available modulation are unable to prevent rapid on–off cycling. Per day, half of combi boilers studied average more than 50 starts and 70% of starts average less than 10 min during space heating operation. Cycling contradicts assumptions in efficiency testing standards, which assume steady state operation, weighted by full and part power measurements. Addressing oversizing and excessive boiler cycling provides an opportunity to quickly and significantly reduce emissions associated with heating, at low cost through the ongoing replacement of millions of boilers. Practical application: Lessons learned from this research regarding the detrimental performance issues seen in gas combi boilers are directly applicable to the topics of boiler specification for building service engineers and installers, such as guidelines in CIBSE Guide A, 1 CE54 Whole house boiler sizing method 2 and legislation set out in BoilerPlus from the Department of Business, Energy and Industrial Strategy. Plant size ratio, radiator hydraulic layout and controls can all contribute to the rapid cycling seen in the data and can all be influenced by building service professionals. Boiler modulation range is also crucial and manufacturers need to be aware of the benefits of extending modulation in new products.

ACS Style

George Bennett; Clifford Elwell; Tadj Oreszczyn. Space heating operation of combination boilers in the UK: The case for addressing real-world boiler performance. Building Services Engineering Research and Technology 2018, 40, 75 -92.

AMA Style

George Bennett, Clifford Elwell, Tadj Oreszczyn. Space heating operation of combination boilers in the UK: The case for addressing real-world boiler performance. Building Services Engineering Research and Technology. 2018; 40 (1):75-92.

Chicago/Turabian Style

George Bennett; Clifford Elwell; Tadj Oreszczyn. 2018. "Space heating operation of combination boilers in the UK: The case for addressing real-world boiler performance." Building Services Engineering Research and Technology 40, no. 1: 75-92.

Journal article
Published: 01 May 2018 in Energy and Buildings
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Robust characterisation of the thermal performance of buildings from in-situ measurements requires error analysis to evaluate the certainty of estimates. A method for the quantification of systematic errors on the thermophysical properties of buildings obtained using dynamic grey-box methods is presented, and compared to error estimates from the average method. Different error propagation methods (accounting for equipment uncertainties) were introduced to reflect the different mathematical description of heat transfer in the static and dynamic approaches. Thermophysical properties and their associated errors were investigated using two case studies monitored long-term. The analysis showed that the dynamic method (and in particular a three thermal resistance and two thermal mass model) reduced the systematic error compared to the static method, even for periods of low internal-to-external average temperature difference. It was also shown that the use of a uniform error as suggested in the ISO 9869-1:2014 Standard would generally be misrepresentative. The study highlighted that dynamic methods for the analysis of in-situ measurements may provide robust characterisation of the thermophysical behaviour of buildings and extend their application beyond the winter season in temperate climates (e.g., for quality assurance and informed decision making purposes) in support of closing the performance gap.

ACS Style

Virginia Gori; Clifford Elwell. Estimation of thermophysical properties from in-situ measurements in all seasons: Quantifying and reducing errors using dynamic grey-box methods. Energy and Buildings 2018, 167, 290 -300.

AMA Style

Virginia Gori, Clifford Elwell. Estimation of thermophysical properties from in-situ measurements in all seasons: Quantifying and reducing errors using dynamic grey-box methods. Energy and Buildings. 2018; 167 ():290-300.

Chicago/Turabian Style

Virginia Gori; Clifford Elwell. 2018. "Estimation of thermophysical properties from in-situ measurements in all seasons: Quantifying and reducing errors using dynamic grey-box methods." Energy and Buildings 167, no. : 290-300.

Journal article
Published: 30 March 2018 in Energies
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The performance gap between the expected and actual energy performance of buildings and elements has stimulated interest in in-situ measurements. Most research has employed quasi-static analysis methods that estimate heat loss metrics such as U-values, without taking advantage of the rich time series data that is often recorded. This paper presents a dynamic Bayesian-based method to estimate the thermophysical properties of building elements from in-situ measurements. The analysis includes Markov chain Monte Carlo (MCMC) estimation, priors, uncertainty analysis, and model comparison to select the most appropriate model. Data from two case study dwellings is used to illustrate model performance; U-value estimates from the dynamic and static methods are within error estimates, with the dynamic model generally requiring much shorter time series than the static model. The dynamic model produced robust results at all times of year, including when the average indoor-to-outdoor temperature difference was low, when external temperatures had large daily variation, and measurements were subjected to direct solar radiation. Further, the probability distributions of parameters may provide insights into the thermal performance of elements. Dynamic methods such as that presented herein may enable wider characterisation of the performance of building elements as built, supporting work to reduce the performance gap.

ACS Style

Virginia Gori; Phillip Biddulph; Clifford A. Elwell. A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error. Energies 2018, 11, 802 .

AMA Style

Virginia Gori, Phillip Biddulph, Clifford A. Elwell. A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error. Energies. 2018; 11 (4):802.

Chicago/Turabian Style

Virginia Gori; Phillip Biddulph; Clifford A. Elwell. 2018. "A Bayesian Dynamic Method to Estimate the Thermophysical Properties of Building Elements in All Seasons, Orientations and with Reduced Error." Energies 11, no. 4: 802.

Journal article
Published: 01 November 2017 in Energy and Buildings
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ACS Style

J. Love; J. Wingfield; A.Z.P. Smith; P. Biddulph; T. Oreszczyn; R. Lowe; C.A. Elwell. ‘Hitting the target and missing the point’: Analysis of air permeability data for new UK dwellings and what it reveals about the testing procedure. Energy and Buildings 2017, 155, 88 -97.

AMA Style

J. Love, J. Wingfield, A.Z.P. Smith, P. Biddulph, T. Oreszczyn, R. Lowe, C.A. Elwell. ‘Hitting the target and missing the point’: Analysis of air permeability data for new UK dwellings and what it reveals about the testing procedure. Energy and Buildings. 2017; 155 ():88-97.

Chicago/Turabian Style

J. Love; J. Wingfield; A.Z.P. Smith; P. Biddulph; T. Oreszczyn; R. Lowe; C.A. Elwell. 2017. "‘Hitting the target and missing the point’: Analysis of air permeability data for new UK dwellings and what it reveals about the testing procedure." Energy and Buildings 155, no. : 88-97.

Journal article
Published: 01 October 2017 in Energy Procedia
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ACS Style

Virginia Gori; Clifford Elwell. Characterization of the thermal structure of different building constructions using in-situ measurements and Bayesian analysis. Energy Procedia 2017, 132, 537 -542.

AMA Style

Virginia Gori, Clifford Elwell. Characterization of the thermal structure of different building constructions using in-situ measurements and Bayesian analysis. Energy Procedia. 2017; 132 ():537-542.

Chicago/Turabian Style

Virginia Gori; Clifford Elwell. 2017. "Characterization of the thermal structure of different building constructions using in-situ measurements and Bayesian analysis." Energy Procedia 132, no. : 537-542.

Journal article
Published: 01 October 2017 in Energy Procedia
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ACS Style

Clifford Elwell; Harper Robertson; Jez Wingfield; Phillip Biddulph; Virginia Gori. The thermal characteristics of roofs: policy, installation and performance. Energy Procedia 2017, 132, 454 -459.

AMA Style

Clifford Elwell, Harper Robertson, Jez Wingfield, Phillip Biddulph, Virginia Gori. The thermal characteristics of roofs: policy, installation and performance. Energy Procedia. 2017; 132 ():454-459.

Chicago/Turabian Style

Clifford Elwell; Harper Robertson; Jez Wingfield; Phillip Biddulph; Virginia Gori. 2017. "The thermal characteristics of roofs: policy, installation and performance." Energy Procedia 132, no. : 454-459.

Journal article
Published: 01 October 2017 in Energy and Buildings
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ACS Style

Sofie Pelsmakers; Clifford Elwell. Suspended timber ground floors: Heat loss reduction potential of insulation interventions. Energy and Buildings 2017, 153, 549 -563.

AMA Style

Sofie Pelsmakers, Clifford Elwell. Suspended timber ground floors: Heat loss reduction potential of insulation interventions. Energy and Buildings. 2017; 153 ():549-563.

Chicago/Turabian Style

Sofie Pelsmakers; Clifford Elwell. 2017. "Suspended timber ground floors: Heat loss reduction potential of insulation interventions." Energy and Buildings 153, no. : 549-563.

Research
Published: 26 June 2017 in Building Research & Information
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There are approximately 6.6 million dwellings in the UK built before 1919, predominantly constructed with suspended timber ground floors whose thermal performance has not been extensively investigated. The results are presented from an in-situ heat-flow measuring campaign conducted at 27 locations on a suspended timber ground floor, and the estimated whole-floor U-value compared with modelled results. Findings highlight a significant variability in heat flow, with increased heat loss near the external perimeter. In-situ measured-point U-values ranged from 0.54 ± 0.09 Wm−2 K−1, when away from the external wall perimeter, to nearly four times as high (2.04 ± 0.21 Wm−2 K−1) when near the perimeter. The results highlight the fact that observing only a few measurements is likely to bias any attempts to derive a whole-floor U-value, which was estimated to be 1.04 ± 0.12 Wm−2 K−1 and nearly twice that derived from current models. This raises questions about the validity of using such models in housing stock models to inform retrofit decision-making and space-heating-reduction interventions. If this disparity between models and measurements exists in the wider stock, a reappraisal of the performance of suspended timber ground floors and heat-loss-reduction potential through this element will be required to support the UK’s carbon-emission-reduction targets.

ACS Style

S. Pelsmakers; B. Croxford; C.A. Elwell. Suspended timber ground floors: measured heat loss compared with models. Building Research & Information 2017, 47, 127 -140.

AMA Style

S. Pelsmakers, B. Croxford, C.A. Elwell. Suspended timber ground floors: measured heat loss compared with models. Building Research & Information. 2017; 47 (2):127-140.

Chicago/Turabian Style

S. Pelsmakers; B. Croxford; C.A. Elwell. 2017. "Suspended timber ground floors: measured heat loss compared with models." Building Research & Information 47, no. 2: 127-140.

Journal article
Published: 01 January 2017 in Energy and Buildings
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ACS Style

Virginia Gori; Valentina Marincioni; Phillip Biddulph; Clifford A. Elwell. Inferring the thermal resistance and effective thermal mass distribution of a wall from in situ measurements to characterise heat transfer at both the interior and exterior surfaces. Energy and Buildings 2017, 135, 398 -409.

AMA Style

Virginia Gori, Valentina Marincioni, Phillip Biddulph, Clifford A. Elwell. Inferring the thermal resistance and effective thermal mass distribution of a wall from in situ measurements to characterise heat transfer at both the interior and exterior surfaces. Energy and Buildings. 2017; 135 ():398-409.

Chicago/Turabian Style

Virginia Gori; Valentina Marincioni; Phillip Biddulph; Clifford A. Elwell. 2017. "Inferring the thermal resistance and effective thermal mass distribution of a wall from in situ measurements to characterise heat transfer at both the interior and exterior surfaces." Energy and Buildings 135, no. : 398-409.

Journal article
Published: 24 December 2016 in Energy and Buildings
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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.

ACS Style

Sofie Pelsmakers; R. Fitton; P. Biddulph; William Swan; B. Croxford; S. Stamp; F.C.F. Calboli; David Shipworth; R. Lowe; C.A. Elwell. Heat-flow variability of suspended timber ground floors: Implications for in-situ heat-flux measuring. Energy and Buildings 2016, 138, 396 -405.

AMA Style

Sofie Pelsmakers, R. Fitton, P. Biddulph, William Swan, B. Croxford, S. Stamp, F.C.F. Calboli, David Shipworth, R. Lowe, C.A. Elwell. Heat-flow variability of suspended timber ground floors: Implications for in-situ heat-flux measuring. Energy and Buildings. 2016; 138 ():396-405.

Chicago/Turabian Style

Sofie Pelsmakers; R. Fitton; P. Biddulph; William Swan; B. Croxford; S. Stamp; F.C.F. Calboli; David Shipworth; R. Lowe; C.A. Elwell. 2016. "Heat-flow variability of suspended timber ground floors: Implications for in-situ heat-flux measuring." Energy and Buildings 138, no. : 396-405.