No description available.

No description available.

The construction industry is highly fragmented, consisting of a large number of very small companies that come together as members of non-collocated teams to complete building projects, and who subsequently may never work together again. The industry still faces various challenges in terms of human and organisational issues. The Virtual Enterprise (VE), and other variations of the paradigm, relies on networking organisations as elements forming an alliance or aggregation towards some specific purpose or opportunity. Rather than the VE being a completely new organisational form, the construction industry has adopted many of its characteristics in its modus operandi for some considerable time. The construction industry does not operate effectively as a VE and in consequence faces many problems. These problems could be addressed by the development of ICT solutions geared towards digitally enabling the VE. The success of collaborative work, and the successful design and uptake of such ICT tools to support that work relies not merely on the introduction of different technologies, however, but also on critically analysing `human' aspects of organisation. Using applied research and drawing on a central case study in which a VE solution was developed, tested and evaluated in the context of `real world' scenarios, the thesis addresses the socio-organisational aspects of technological intervention and seeks to answer four research questions dealing with the above. The main results include recognition that whilst ICT are advanced enough to offer adapted solutions to digitally enabling the construction VE, the technology alone is not sufficient. The construction industry is not yet ready to move to an approach employing latest ICT development, due to the need to manage human and organisational issues central to technological intervention. The thesis finally offers business recommendations highlighting and mapping the critical human and organisational decisions that need to be considered.

The ICSSWH (Integrated Collector Storage Solar Water Heater), apart from being the oldest is also the most economical means of solar water heating. The effect of modifications in the collector geometry has frequently appeared in the literature, and over the time, has resulted in different designs. These designs differ mainly on the site of installation as well as the target application. A novel design created by Professor T Muneer at Napier University, utilizes fins inside the storage tank to improve the heat transfer. The reported field tests of the fin type ICSSWH have indicated a 10 % improvement in the solar fraction compared to unfinned. As ICSSWH is the lowest cost, it presented a possible solution for the Scottish market where Energy Saving Trust estimates that 50% of hot water demand of a household can be met through solar water heating. In the present research program, two prototype collectors (one with- and one without fins) were fabricated at Napier University by the author. The collectors were then tested in the laboratory on identical experimental schemes to determine their respective performance. Simulations based on analytical modelling were then undertaken, using numerous experimental data for validation that were obtained during the course of the present work. A high degree of conformance was noted between the two. Furthermore, for a deeper insight, Computational Fluid Dynamics (CFD) analysis was performed. This research focuses on the qualitative and quantitative assessment of the heat transfer due to the fins. The difference in the performance with respect to the change in tilt angle was also studied. This study can therefore be utilised for developing solar water heating systems for any given location. Note that there is an intrinsic link between the latitude and inclination angle of the collector plate. The nocturnal loss from the collector is the principal factor that has inhibited the wide spread use of the ICSSWH. The remedies to abate this problem have therefore been attempted. In addition to that, the collectors have to be integrated with the domestic hot water supply system and plumbing considerations have to be incorporated within the overall design. The supply circuits were worked out and the measures for freeze and boil protection were devised. The optimization of any system is an intrinsic task particularly when several variables are involved. On the basis of the obtained results from simulations and experiments, the influential design variables were identified. The values for these variables which lead to the optimal design in terms of thermal performance were assessed while keeping the overall manufacturing cost of the collector as low as possible. Recommendations for future work have also been presented.

In 1987 the World Commission on Environment and Development proposed a reduction in per capita energy consumption of 50%. Increasing demands, and initiatives of this nature, produce a need for more reliable assessment methods, measurement tools and improvement regimes. Since the late 1960's Life Cycle Assessment (LCA) has become an increasingly important tool for engineers, technologists, scientists, designers, managers and environmentalists alike. LCA enables the effects which products, processes and activities have on local, regional or global environments to be assessed, adopting a holistic, or whole life approach to design methodologies. The design of window systems has a large impact upon LCA results generated. Thermal performance properties influence energy consumption patterns throughout a lifetime of use, while appropriate use of materials, window positioning and size have a knock-on effect on lighting control functions and air conditioning demands. In developing countries, residential sectors account for between 20% and 30% of the total energy used (30% in the UK). Windows in dwellings alone account for 6% of the total UK energy consumption. This thesis addresses an ongoing need to focus on sustainable development, using LCA as an assessment tool to develop a greater understanding of the window life cycle, and to highlight improvements which are necessary to lessen its environmental impact and make the processes involved more benign. To do this successfully requires that the demands of modern day living, and the comfort conditions expected, be incorporated into design criteria, whilst ensuring that the needs of future generations are not compromised by today's activities. Along with rising demands to improve efficiency and decrease energy consumption in buildings, comes an expectation for continual improvement in building interiors. To this end, both the aural and visual haracteristics of window installations become paramount, in addition to the well researched thermal performance criteria. Much research has focused on investigating the social and physiological benefits associated with improved interior environments. The correlation between worker satisfaction and performance has been well proven. If complete physical well-being is satisfied then an individual's mental well-being is less likely to be affected by the additional stressors of environmental dissatisfaction. An optimisation model has been developed, linking the thermal, aural and visual performance of varying window designs, such that an "advanced" window system is created. Two outputs are generated from the model, which may be used to evaluate the "optimum" window design in terms of energy consumption and global environmental impact. Optimisation of energy consumption incorporates embodied energy, thermal performance and electric lighting demand, over the life cycle of a window. Global environmental impact optimisation is similar, but evaluation is based on energy generation, and greenhouse gas production. Finally, a flowchart for optimisation guides the user towards a glazing solution which offers sufficient noise attenuation, whilst minimising thermal losses and electric lighting demand. Each output provides a guide for design, leaving room for judgement, and is not intended to be followed definitively. Recommendations for improvements to manufacture systems and production of multiglazed windows are offered, based on sustainable development criteria. Future research needs, which are necessary to minimise the total environmental impact resulting from multi-glazed window production, are also discussed.

Timber platform frame has evolved as an efficient method of construction for domestic dwellings and is experiencing continual growth in the UK due to it lending itself to off-site modem methods of construction (MMC), being environmentally efficient and exhibiting structural robustness. The challenge faced by the industry in the UK is to continue the evolutionary process such that the future demands of off-site MMC and regulatory changes are met. By conducting a study of the development of timber platform frame construction and reviewing the current and future requirements of the domestic dwelling construction market the challenges for the industry were highlighted. The business drivers of a timber platform frame manufacturer were considered and in conjunction with the information from the review an agenda of research programmes was derived. The objective of the research, although primarily from a structural timber engineering perspective, was to address the challenges faced by the industry employing a holistic approach with a view to implementing applied research. The UK procurement process for domestic dwelling construction is such that building layout is determined by architectural requirements. Building layout can have an adverse effect on structural stability and result in an inefficient system. A design review was conducted to determine the influencing factors which impinge upon system stability as a result of which recommendations for improvements were made. From the investigation the transfer of shear from a wall diaphragm to the foundation was deemed critical. Therefore, an experimental study was carried out which has resulted in an optimised specification. Further to this mathematical modelling techniques were used to demonstrate the impact that architectural layout has on stability, quantifying the financial penalty of inefficient layout and making recommendations to improve current designs. One of major priorities of the UK Government is to reduce climate change by implementing a low carbon economy with sustainable production and consumption; all with duty of care towards natural resources. Improvements to the Building Regulations (2006), in conjunction with other requirements, will result in wall U-values in domestic dwellings to be between 0.27 to 0.30W/m2K. To determine an efficient method of meeting the new regulations an all encompassing research programme was conducted with the primary function being to develop a sustainable method of achieving thermal efficiency. Another method of wall construction is Structural Insulated Panels (SIPs) and this option was reviewed. Initial work by Kermani (2005) on the structural performance of SIPs was extended to examine their racking characterisitcs with comparative studies to European and British structural codes of practice carried out. One of the key industry drivers which the review highlighted was the need for the implementation of lean technologies. The fabrication of flitch beams (timber-steel-timber sandwich configuration), used in cases of onerous load span conditions and limited depth of section, was improved through the implementation of a shot fired dowel connection method. To optimise the method of fabrication and achieve implementation an extensive laboratory study was carried out the results of which are compared to European structural codes of practice with recommendations made for design. The implementation of off-site MMC methods results in a change in associated risk during construction from minor consequence and high risk to major consequence and low risk. The crane erect method of timber platform frame construction optimises on-site performance in terms of both time and cost and reduces the requirement of working at height, which on average causes almost one fatality every week. The biggest health and safety risk associated with the crane erect method is failure of the roof system when being lifted into position. Using an analytical model, verified by full scale laboratory testing, a range of lifting conditions were researched and a best practice lifting procedure was developed which allows the safe lifting of standard roof systems used in domestic dwelling construction.

The dynamic response of structural timber flooring systems can cause vibrational serviceability problems in terms of discomfort experienced by the occupants. A unified method to control timber floor vibrations has not been established to-date. The vibration problem is manifold. The complexity and the limited amount of research with respect to timber floor vibrations have shown an urgent need for further investigations. This thesis has focused on the effects of structural and non-structural modifications on the dynamic performance of timber flooring systems by using experimental data from sixty-seven full-scale flooring systems for analytical investigations so as to identify structural configurations and vibration parameters, which are promising to further the design against disturbing vibrations. The collected data have also been used to identify weaknesses of current design criteria and to build and validate a finite element (FE) model for eigenproblem analyses of timber I-joist floors. The experimental work has been carried out with support from industry, and part of the investigations with respect to the design criteria has been conducted as Visiting Scientist within a Short Term Scientific Mission of COST Action E55 at VTT - Technical Research Centre of Finland in Espoo, Finland. The significant effects of floor make-up and different configurations on their dynamic response are examined, with specific interest to stiffen dynamically sensitive locations targeted, and the most promising designs (configurations) are identified. The important effects of damping on the dynamic performance of flooring systems are addressed by determination of damping ratios from the full-scale experimental work. The results were then used to perform a series of statistical studies to identify and recommend more appropriate damping ratios for design of bare light-weight timber flooring structures based on a number of distinct structural properties. The computer-based finite element analysis has been successfully used to model a series of timber flooring systems incorporating timber I-joists for predicting modal parameters and their relative changes due to structural modifications. The analysis has demonstrated the significant influence of assigning spring stiffness at the supports and at the interface of deck and joists on the floor responses. Overall, this research has helped to achieve a much broader knowledge and greater understanding of dynamic response and vibrational characteristics of timber flooring systems, and has made a contribution to identifying improved structural design and furthering vibration prediction and assessment. Undertaking of any such measures and future work as suggested in this thesis could significantly contribute to the improvement of the structural design and the design to Eurocode 5 if results are incorporated in future revisions. This would lead to fewer nuisances for residential occupants and enhanced quality of life.

No description available.

According to current climate change predictions for the UK, summers are expected to become dryer and hotter in the future. This has potentially serious implications for overheating of naturally ventilated office buildings, many of which already fail to perform under current heatwave conditions. This thesis addresses the summer performance of such buildings under current and future climates by means of building performance simulation. Current industry standard weather datasets for building performance simulation are not however, suited to the assessment of the potential impacts of a changing climate. This work describes the integration of future climate scenarios into widely used weather file formats and critically assesses the resulting weather datasets. Simulations of a case study building at the University of Southampton highlight the potential impact of climate change on future summer overheating inside naturally ventilated buildings. The results of these simulations are compared to monitored data from the case study building during an extended heatwave period in the summer of 2006. It is shown that the present day performance of a naturally ventilated building under an extended heatwave period can give an indication of its likely performance during a projected typical hot summer in the 2050’s under a medium-high emissions scenario. A second case study building serves to highlight that building designs and building services solutions which are suitable for retaining acceptable indoor comfort levels during current heatwave periods, are likely to be suitable to alleviate summer overheating under the predicted warmer future climates. Further simulations, encompassing various locations throughout the UK emphasize the need for timely refurbishment of naturally ventilated office buildings within the next few decades to avoid increasing numbers of existing buildings failing to perform under the predicted future summer conditions.

The study of the buoyancy–driven displacement ventilation flows has been conducted earlier through both mathematical modelling and experiments. There can be some assumptions made in the studies for thermal analysis such as: adiabatic boundaries, neglecting radiation heat transfer between wall surfaces, and neglecting the absorptivity of the air on simulating the thermal distribution within the ventilated spaces. This study considers heat conduction at boundaries, heat radiation between wall surfaces and radiative absorptivity of the air when modelling buoyancy-driven displacement ventilation flows. The simulations were carrying out using computational fluid dynamic (CFD) programme Star-CCM+. This study investigates the influence of the absorptivity of the air on thermal distribution within an enclosure ventilated by buoyancy-driven displacement ventilation flows. Two cases of buoyancy-driven displacement ventilation experiments conducted early by Sandbach (2009) and Li et al. (1993b) were modelled. To consider the absorptivity of the air, the local weather data were retrieved and were used for calculating the absorption coefficient of the air under different weather conditions. The participating media radiation model was employed to compute the radiation heat absorbed by the air. In addition, the performances of the turbulence models on modelling buoyancy-driven displacement ventilation flows were investigated to ensure the predicted results were accurate and satisfactory. The simulation results presented in this study have shown to agree well with the experimental data in two different experiment cases. In the case of the experiments conducted by Sandbach and Lane-Serff (2011b), the predicted results match well with the measurements when considering absorptivity of the air. The errors between the simulation results and the measurements were less than 10% in most cases. The results also suggest that the absorption coefficient has an influence on ventilation flow rate and consequently has an effect on the strength of the stratification. This indicates that the absorption coefficient should be determined according to the conditions rather than be given an one-and-for-all value. The simulation results have also shown to agree well with the measurements given in the literature presented by Li et al. (1993b). The effect of the absorptivity was shown to be more significant in the case of high supply airflow temperature or high supply heat load. Hence, radiative absorptivity of the air should be taken into account in order to accurately model the thermal distribution in the ventilated enclosure.