• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • No language data
  • Tagged with
  • 18
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Performance-based methodology for the fire safe design of insulation materials in energy efficient buildings

Hidalgo-Medina, Juan P. January 2015 (has links)
This thesis presents a methodology to determine failure criteria of building insulation materials in the event of a fire that is specific to each typology of insulation material used. This methodology is based on material characterisation and assessment of fire performance of the most common insulation materials used in construction. Current methodologies give a single failure criterion independent of the nature of the material – this can lead to uneven requirements when addressing materials of different characteristics. At present, fire safety codes establish that performance of different materials or assemblies is assumed to be “equivalent” when subject to the same test, where attainment of the unique failure criteria occurs after a required minimum time. Nevertheless, when using extremely different materials this may not be actually the case. Building performance is currently defined in a quantitative way with respect to factors such as energy usage (i.e. global thermal transmittance), element weight (i.e. thickness and mass), space utilisation and cost of application. In the case of fire performance, only a threshold value is required, therefore a quantitative performance assessment is not conducted. As a result, the drivers are those associated with the variables that can be quantified, whereas the thresholds merely need to be met without any alternative for a better performance. This work opens the door to a performance-based-design methodology that takes into account fire performance as an optimisation variable for the building design, to be used with all other quantifiable variables. An added advantage is that the numerical tool required embraces a low level of complexity. As a result, the possibility for any insulation product to achieve quantifiable and acceptable fire safety levels for required energy efficiency targets is established. As a final remark, an application of the performance assessment methodology that introduces fire safety as a quantifiable variable is presented.
12

Fire engineering in sustainable buildings : an evaluation for the application of performance-based design in Abu Dhabi

Al Hashmi, Emad January 2016 (has links)
Sustainable Building Design and Engineering is an integrated approach to energy, health, and operational performance. Abu Dhabi, the capital of United Arab Emirates (UAE) is experiencing a phenomenal growth in built environment. In this context, the Abu Dhabi Government has taken initiatives and measures to sustainable building designs development. This research aimed to develop a guideline for the application of performance- based fire-engineering design with sustainable building designs. In addition, it builds a referral information base helping to build sustainable communities, where fire- related fatalities and risks mitigated. Identifying fire safety and sustainability relation, and assessing technical and regulatory challenges with performance-based designs (PBD) in buildings are also part of this study. It also investigated current practices in sustainable building design and fire safety measures applied by Abu Dhabi Civil Defence (ADCD) under the existing construction legislations. The overall results of the study addressed three main areas, namely, sustainability, fire safety, and legality of the construction industry in Abu Dhabi. The data obtained from the case studies, the questionnaire and face-to-face interviews revealed a strong element of misunderstanding regarding the accurate definition of sustainable building design in Abu Dhabi especially among the stakeholders, including the enforcers. This is by pushing towards sustainable design concepts and technologies without taking into consideration the effects on fire safety level from one side and misunderstanding of the local conditions that shape a local definition for building sustainability in Abu Dhabi hot humid climate. Second, the results relating to fire safety measures in Abu Dhabi showed that some factors in the sector of fire safety seemed to affect the accurate application of Performance- Based Design (PBD). These factors were considered as technical and administrative challenges facing the application of PBD and its safety level. Third, the existing local construction legislation and regulations do not support the application of sustainable building design in innovative designs that implementing fire engineering approach. This includes the lack of legislation, disintegration of requirements between building regulators and absence of law enforcement on building owners. The overall findings of this study showed that the application of fire engineering in the innovative sustainable design under the existing construction legislations and culture could have some serious issues to overcome before achieving accepted safety level. In conclusion, there is a common perception that application of sustainable building design can increase fire safety risk. Innovative fire engineering applications compromises on sustainability and vice-versa. A number of similar studies in Abu Dhabi have shown reduction in fire safety on applying performance- based designs. These are challenging issues with the Governments and they are concerned with the local authorities. The building industries in Abu Dhabi need guidelines to find a trade-off between fire safety and sustainability with application of performance based designs.
13

Practice, policy and professional roles : unintended consequences and performance gaps in UK domestic solid wall insulation retrofit projects

Forman, Timothy January 2015 (has links)
Space heating in domestic buildings accounts for roughly one-fifth of UK greenhouse gas emissions. There are roughly 11 million homes in the UK potentially suitable for solid wall insulation (including hard-to-treat cavity constructions). Remarkably, approximately 97 per cent of homes built with solid walls have no wall insulation. Retrofitting these homes with insulation offers the potential to significantly reduce national greenhouse gas emissions while reducing expenditure on fuel, improving thermal comfort and realising numerous important associated benefits. This research began at the onset of an upsurge in national rates of solid wall insulation retrofit in 2011-2012. At that time, anecdotal reports pointed toward a legacy of poor practices and continued problems in the retrofit industry. A literature review outlines knowledge about the risks of performance gaps and unintended consequences. Participant and non-participant observation, site inspection and qualitative study are employed in area-based retrofit projects and across a variety of related settings. Analysis interprets observations against a range of existing theory and develops new theoretical insights. Findings convey an understanding of a subset of the landscape in which retrofitting occurs and identify a number of challenges to improving practice. The perspectives of installers, managers, trainers and a range of professionals are reported. The research suggests that unintended consequences are likely to result from many observed practices and cautions that if these practices are typical of wider realities and remain unchanged, then serious problems may be propagated across many projects if growth in retrofitting continues as expected. Findings identify factors of quality in retrofits ranging from construction management, training, certification, technology, identity and motivation, and government policy instruments. Emerging from the research is a definition of ‘quality’ against which retrofits can be evaluated. This forms the basis for evaluation of a number of proposed interventions and routes to improved practice.
14

Integrating active thermal mass strategies in responsive buildings

Warwick, David James January 2010 (has links)
Thermal mass can be used in buildings to reduce the need for and dependence on mechanical heating and cooling systems whilst maintaining environmental comfort. Active thermal mass strategies further enhance the performance of thermal mass through integration with the Heating, Ventilation and Air Conditioning (HVAC) systems. For the design of new buildings to include active thermal mass strategies, experience from operational projects and design guidelines are normally used by engineers. However, dynamic thermal modelling is required in most cases to accurately determine the performance of its integration with the environmental systems of the building. Design decisions made in the preliminary stages of the design of a building often determine its final thermal characteristics. At this stage, reasons for not integrating active thermal mass strategies include the lack of knowledge about the performance of previous buildings and the time and resources required to carry out detailed modelling. In this research project a commercially available dynamic building thermal program has been used to construct models for active thermal mass strategies and compare the results with monitored temperatures in buildings incorporating the strategies in the UK. Four active thermal mass strategies are considered (a) hollow core slabs (HCS), (b) floor void with mass, (FVWM) (c) earth-to-air heat exchanger (ETAHE) and (d) thermal labyrinth (TL). The operational strategies and monitoring are presented and their modelling is described in terms of geometrical configuration and input parameters. The modelling results are compared with the measured parameters successfully. Using the calibrated model, an excel based tool (TMAir) was then developed that can be used at the concept design stages of a typical office building to determine the benefits of integrating an active thermal mass strategy. Key design parameters were identified for each system. These parameters can be split into two categories; fixed parameters and user selected parameters. The fixed parameters are pre-selected for the design tool and have to be a fair representation of the projects that the tool will be used for. The user selected parameters are chosen by the user to represent the way the building will be used, and to look at the effect of key design decisions on the performance of the building. The tool has an easy-to-use interface which allows direct comparison of the different active thermal mass strategies together with the effects of changing key design parameters. Results are presented in terms of thermal comfort and energy consumption. TMAir has then been used to carry out a series of parametric analyses. These have concluded the following:  There is only a benefit in integrating a HCS strategy when night cooling is introduced  There is no benefit in integrating a FVWM strategy when only one parameter is improved  An ETAHE and TL strategy will always provide a benefit, although the benefits are greater when night cooling is introduced, solar and internal gains are reduced and when the air change rate is increased. When all of the parametric improvements are applied to the test room the results show that all of the active thermal mass strategies can provide a reduction in annual overheating hours when compared to the Standard Strategy. Only a small benefit is found for the FVWM Strategy, however around a 25% reduction is found for the HCS Strategy, over a 50% reduction for the TL Strategy and nearly a 75% reduction for the ETAHE Strategy. This demonstrates the importance of applying a low energy, passive approach when considering the application of active thermal mass strategies. The key results have shown that when comfort cooling is provided, adding a HCS or FVWM strategy always results in an increase in the annual cooling load. This is as a result of the temperature of the air being supplied into the cores or floor void being higher than that of the internal surface temperatures of the cores or void. This results in the supply air being heated, and less cooling provided to the test room per cooling energy delivered. Due to the pre cooling effect of the ETAHE and TL strategies, these strategies always result in a reduction in the annual cooling load. The key results have shown that the annual heating load is reduced by a small amount for the HCS and FVWM strategies unless the solar gains or internal gains are reduced, whereas the ETAHE and TL strategies always result in a around a 10% reduction in annual heating load as a result of the preheating effect these strategies have on the supply air.
15

Economics of fire : exploring fire incident data for a design tool methodology

Salter, Chris January 2013 (has links)
Fires within the built environment are a fact of life and through design and the application of the building regulations and design codes, the risk of fire to the building occupants can be minimised. However, the building regulations within the UK do not deal with property protection and focus solely on the safety of the building occupants. This research details the statistical analysis of the UK Fire and Rescue Service and the Fire Protection Association's fire incident databases to create a loss model framework, allowing the designers of a buildings fire safety systems to conduct a cost benefit analysis on installing additional fire protection solely for property protection. It finds that statistical analysis of the FDR 1 incident database highlights the data collection methods of the Fire and Rescue Service ideally need to be changed to allow further risk analysis on the UK building stock, that the statistics highlight that the incidents affecting the size of a fire are the time from ignition to discovery and the presence of dangerous materials, that sprinkler activations may not be as high as made out by sprinkler groups and that the activation of an alarm system gives a smaller size fire. The original contribution to knowledge that this PhD makes is to analyse the FDR 1 database to try and create a loss model, using data from both the Fire Protection Association and the Fire and Rescue Service.
16

Development of vacuum insulation panel with low cost core material

Alam, Mahmood January 2015 (has links)
Buildings consume around half of the UK's total energy consumption and are responsible for almost 50% of UK's total carbon dioxide (CO2) emissions. Use of high thermal resistance insulation in buildings is critical to save the substantial amounts of space heating energy lost through building fabric. Conventional building insulation materials have higher thermal conductivity values ranging from 40 mWm-1K-1 (Glass fibre) - 26 mWm-1K-1 (Polyurethane foam) and require larger thicknesses to achieve stringent building regulation requirements which may not be feasible due to techno-economic constraints. Vacuum Insulation Panel (VIP) is a relatively new insulation for building applications that offers 5-8 times higher thermal resistance and can achieve significant space savings in buildings. VIPs are produced as a rigid panel comprising inner core board laminated in an outer high barrier envelope under evacuated conditions (< 5mbar). However, the main challenge for large scale acceptance of VIPs in building applications is their higher cost. VIPs have been shown to have an approximately 10 times longer payback compared to conventional EPS insulation due to their high initial cost. Expensive materials currently being used for VIP manufacturing such as fumed silica contribute to high cost of VIPs and it is critical to identify alternative low cost materials for VIP components to overcome the challenge of high cost. The aim of this thesis was to develop an alternative low cost material and investigate its suitability for use as VIP core. Expanded perlite, a low cost material was identified as a replacement of expensive fumed silica in a VIP core. Composite samples containing expanded perlite, fumed silica, silicon carbide (SiC) and polyester fibres were developed by dry mixing of the constituents in different mass ratios and their different properties were experimentally measured to identify optimum composition of composite. Gaseous thermal conductivity at different pressures was calculated from the pore size data obtained using Mercury Intrusion Porosimetry (MIP), gas adsorption and electron microscopy. Radiative conductivity of composite samples was measured using Fourier Transform Infrared (FTIR) to ascertain the opacifying effect of expanded perlite and opacifier (SiC). Centre of panel thermal conductivity of core boards of size 100mm x 100mm made of composite material at atmospheric pressure was measured by using a small guarded hot plate device. Average pore diameter values of expanded perlite decreased with the partial filling of fumed silica aggregates and was found to be in the range of 150-300 nm yielding lower gaseous conductivity values of 1.2-2.1 mWm-1K-1 at 100mbar and became negligible upon further decreasing pressures below 10 mbar. Core boards made of optimised composite containing 30% expanded perlite and 50% fumed silica along with SiC and polyester fibres was found to achieve centre of panel thermal conductivity of 28 mWm-1K-1 at atmospheric pressure and the average radiative conductivity of 0.67 mWm-1K-1 at 300K with its gaseous thermal conductivity at 1 mbar being 0.016 mWm-1K-1. According to the results of the thesis VIP prototypes consisting of core made with optimised composite consisting (50 mass% of fumed silica, 30 mass% of expanded perlite along with 8 mass% of fibre and 12 mass% of SiC) yielded centre of panel thermal conductivity of 7.4-7.6 mWm-1K-1 at pressure of 0.53-0.64 mbar. Opacifying properties of expanded perlite were observed and quantified. Expanded perlite reduced the radiative conductivity of the composite requiring smaller quantities of high density opacifiers such as SiC. For sample containing no expanded perlite, average radiative conductivity was calculated to be 1.37 mWm-1K-1 and radiative conductivity values decreased to 1.12 mWm-1K-1, 0.67 mWm-1K-1, 0.63 mWm-1K-1 and 0.50 mWm-1K-1 with mass ratio of expanded perlite 20%, 30%, 40% and 60% respectively. It was concluded that the solid conductivity of prototypes VIPs was 1.8-2 times higher compared to those of commercially available VIPs and is the main reason for higher centre of panel thermal conductivity.
17

Energy efficiency improvements in traditional buildings : exploring the role of user behaviour in the hygrothermal performance of solid walls

Herrera Gutierrez-Avellanosa, Daniel January 2016 (has links)
Thermal improvement of traditional and historic buildings is going to play a crucial role in the achievement of established carbon emission targets. The suitable retrofit options for traditional buildings are, however, very limited and their long term performance is still uncertain. Evaluation of risks, prior to any alteration of building physics, is critical to avoid future damage to the fabric or occupants’ health. Moisture dynamics in building envelopes are affected by the enclosure’s geometry, materials properties and external and internal boundary conditions. Since the internal boundary is heavily influenced by users, understanding their behaviour is essential to predict the outcome of energy retrofit measures more accurately. The effect of user behaviour on energy demand has been extensively investigated; however, its impact on the hygrothermal performance of the envelopes has barely been explored. This research approached the connection between users and buildings from a new angle looking at the effect that user behaviour has on moisture dynamics of buildings’ envelopes after the retrofit. Qualitative and quantitative research methods were used to develop a holistic evaluation of the question. Firstly, factors influencing the adoption of energy efficiency measures in traditional buildings were explored by means of semi-structured interviews with private owners and project managers. Subsequently, a multi-case study including interviews with occupants and monitoring of environmental conditions was conducted. Data collected at this stage was used to explore users’ daily practices of comfort and to characterise the internal climate of traditional dwellings. Lastly, users’ impact was quantified using Heat, Air and Moisture (HAM) numerical simulation. This allowed for the evaluation of the hygrothermal performance of walls under different internal climate scenarios. Combined results of interviews, environmental monitoring and simulation showed that internal climate can compromise envelope performance after the retrofit and highlighted the need to consider users in the decision making process. Ultimately, the results of this research will help to increase awareness about the potential impact of user behaviour and provide recommendations to decision makers involved in the energy retrofit of traditional structures.
18

Life cycle costing methodology for sustainable commerical office buildings

Oduyemi, Olufolahan Ifeoluwa January 2015 (has links)
The need for a more authoritative approach to investment decision-making and cost control has been a requirement of office spending for many years now. The commercial offices find itself in an increasingly demanding position to allocate its budgets as wisely and prudently as possible. The significant percentage of total spending on buildings demands a more accurate and adaptable method of achieving quality of service within the constraints on the budgets. By adoption of life cycle costing techniques with risk management, practitioners have the ability to make accurate forecasts of likely future running costs. This thesis presents a novel framework (Artificial Neural Networks and probabilistic simulations) for modelling of operating and maintenance historical costs as well as economic performance measures of LCC. The methodology consisted of eight steps and presented a novel approach to modelling the LCC of operating and maintenance costs of two sustainable commercial office buildings. Finally, a set of performance measurement indicators were utilised to draw inference from these results. Therefore, the contribution that this research aimed to achieve was to develop a dynamic LCC framework for sustainable commercial office buildings, and by means of two existing buildings, demonstrate how assumption modelling can be utilised within a probabilistic environment. In this research, the key themes of risk assessment, probabilistic assumption modelling and stochastic assessment of LCC has been addressed. Significant improvements in existing LCC models have been achieved in this research in an attempt to make the LCC model more accurate and meaningful to estate managers and high-level capital investment decision makers A new approach to modelling historical costs and forecasting these costs in sustainable commercial office buildings is presented based upon a combination of ANN methods and stochastic modelling of the annual forecasted data. These models provide a far more accurate representation of long-term building costs as the inherent risk associated with the forecasts is easily quantifiable and the forecasts are based on a sounder approach to forecasting than what was previously used in the commercial sector. A novel framework for modelling the facilities management costs in two sustainable commercial office buildings is also presented. This is not only useful for modelling the LCC of existing commercial office buildings as presented here, but has wider implications for modelling LCC in competing option modelling in commercial office buildings. The processes of assumption modelling presented in this work can be modified easily to represent other types of commercial office buildings. Discussions with policy makers in the real estate industry revealed that concerns were held over how these building costs can be modelled given that available historical data represents wide spending and are not cost specific to commercial office buildings. Similarly, a pilot and main survey questionnaire was aimed at ascertaining current level of LCC application in sustainable construction; ranking drivers and barriers of sustainable commercial office buildings and determining the applications and limitations of LCC. The survey result showed that respondents strongly agreed that key performance indicators and economic performance measures need to be incorporated into LCC and that it is important to consider the initial, operating and maintenance costs of building when conducting LCC analysis, respondents disagreed that the current LCC techniques are suitable for calculating the whole costs of buildings but agreed that there is a low accuracy of historical cost data.

Page generated in 0.041 seconds