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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Field trialling of a new airtightness tester in a range of UK homes ABSTRACTA low pressure 'quasi-steady' pulse technique for determining the airtightness of buildings has been developed and compared with the standard blower-door technique for field-testing a range of UK homes. The reported low pressure air pulse unit (APU) for determining the airtightness of buildings, through several development stages related to optimizing the algorithm, pressure reference and system construction, has been trialled under various testing and environmental conditions to assess its repeatability and accuracy. The houses, representative of the UK housing stock, mostly have high levels of air leakage; resulting in poor energy performance and imbalanced indoor environments. The results of the pulse techniques are also compared with the standard blower door technique. A comparison between the results obtained using the two techniques is presented, which indicates that the pulse technique is reliable for determining building leakage at low pressure. Repeatability of consecutive tests in identical conditions is found to be within ± 5% of the mean, and within ± 8% when tested under different environment conditions. It has also been shown that the correct tank/valve combination is necessary to achieve the required quasi-steady flow. Tests for accuracy using the addition of known openings have been conducted and shown that uncertainties are hard to eliminate for a clean comparison when testing conditions are not controlled.

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Cellulosic-crystals as a fumed-silica substitute in vacuum insulated panel technology used in building construction and retrofit applications, Energy and Buildingshttp://dx.doi.org/10. 1016/j.enbuild.2017.08.058 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis article investigates impact of substituting fumed silica with a cellulosic-crystal innovation in a commercial Vacuum Insulated Panel (VIP) core. High building performance demands have attracted VIP technology investment to increase production capacity and reduce cost. In building retrofit VIPs resolve practical problems on space saving that conventional insulations are unsuitable for. Three challenges exists in fumed silica: cost, low sustainability properties, and manufacture technical maturity. Cellulosic nano-crystal (CNC) technology is in its infancy and was identified as a possible alternative due to a similar physical nano-structure, and biodegradability. The study aim was to determine a performance starting point and establish how this compares with the current benchmarks. Laboratory cellulosic-crystal samples were produced and supplied for incorporation into commercial VIP manufacture. A selection of cellulosic-panels with core densities ranging 127 -170 kg/m 3 were produced. Thermal conductivities were tested at a pressure of 1 Pa (0.01 mBar), with the results compared against a selection of fumed silica-VIPs with core densities ranging 144 -180 kg/m 3 . Conductivity tests were then done on a cellulosic-VIP with 140 kg/m 3 density, under variable pressures ranging 1 -100,000 Pa (0.01 -1000 mBar). This investigated panel lifespan performance, with comparisons made to a fumed silica-VIP of similar core density. Manufactured cellulosic-samples were found unsuitable as a commercial substitute, with performance below current standards. Areas for cellulosic nano-material technology development were identified that show large scope for improvement. Pursuit could create a new generation of insulation materials that resolve problems associated with current commercial versions. This is most applicable in building retrofit where large ranges of domestic and commercial cases are marginalised from their construction markets due to impracticalities and high upgrade costs. This being a problem in multiple economies globally. Figure 3 with typical layer thicknesses [1,13].VIP thermal conductivities are five to ten times lower than commercial insulations, with the centreof-panel reaching 4 mW/m.K [3,4,14,16]. Albeit excellent performance, the technology is expensive with panel prices multiples of five to ten that of standard insulations [...