Micro- generation is the small-scale and localised provision of heat or electricity. Micro-generators have the potential to reduce greenhouse-gas emissions and enhance energy security by providing heat or electricity from either renewable sources, or via the more efficient use of fossil fuels. But this potential is often unquantified or unclear, and hence quantitative information is required concerning both the energetic performance of micro-generators and their ability to provide net reductions in carbon emissions. <br /> In the context of household energy provision in the UK, thermodynamic and related carbon analyses of three micro-generation technologies have been carried out. These studies contribute to the research of the SUPERGEN ‘Highly Distributed Power Systems’ Consortium, which has been addressing a broad range of issues regarding micro-generation. The technologies analysed here are a grid-tied micro-wind turbine (rotor diameter 1.7m, rated power 600 W at 12 m/s), a grid-tied solar photovoltaic array (15 m2, 2.1 kWp mono-crystalline silicon), and a solar hot-water system (2.8 m2 flat-plate collector, direct-feed system). Annual energy outputs were estimated and contextualised against the demands of representative UK households. The overall energy-resource and carbon savings provided by the micro-generators were assessed on the basis that they (partially) displace the established supply systems. Savings were then compared with the energy-resource and carbon ‘debts’ of the micro-generators to determine their net performance. <br /> The displaced energy or carbon payback periods of the micro-generators were estimated to be well within their estimated lifetimes: a maximum 2.5 years for the SHW system, 3.1 years for the micro-wind turbine installed in an ‘open’ environment, and 7.4 years for the solar PV system. After payback, net energy-resource and carbon savings accrue. This thesis thus demonstrates that, given appropriate UK installations, all three micro-generators can reduce carbon emissions and enhance energy security by reducing use of, and dependence upon, fossil fuels.

The aim of this thesis is to take a broad conceptual overview of the global energy system and investigate what the aims of sustainability might entail for such a system. The work presented uses a biophysical economic approach in that the dynamics of the global economy are investigated using the tool box of the physical sciences, including the laws of thermodynamics and the methods of energy analysis. Modern society currently uses approximately 500 exajoules (EJ = 10^18 J) of total primary energy supply (TPES) each year. This energy consumption has been increasing at roughly 2% per year for the past two hundred years. TPES is currently dominated by three non-renewable energy sources: coal, oil and gas which, together with energy from nuclear fission of uranium, make up around 85% of the energy market. Consumption of finite resources at a continuously growing rate is not sustainable in the long-term. A trend in policy direction is to seek a transition to renewable sources of energy. This thesis seeks to explore two questions: are the technical potentials of renewable energy sources enough to supply the current and/or projected demand for energy and what would be the effect on the physical resource economy of a transition to an energy supply system run entirely on renewable energy sources? The Global Energy Model using a Biophysical Approach (GEMBA) methodology developed here is compared and contrasted with other approaches that are used to study the global energy-economy system, including the standard neoclassical economic approach used in such models as MESSAGE and MARKAL. A number of meta-analyses have been conducted in support of the GEMBA model. These include: meta-analysis of historic energy production from all energy sources; meta-analysis of global energy resources for all energy sources; meta-analysis of energy-return-on-investment (EROI) for all energy sources. The GEMBA methodology uses a systems dynamic modelling approach utilising stocks and flows, feedback loops and time delays to capture the behaviour of the global energy-economy system. The system is decomposed into elements with simple behaviour that is known through energy analysis. The interaction of these elements is captured mathematically and run numerically via the systems dynamics software package, VenSim. Calibration of the model has been achieved using historic energy production data from 1800 to 2005. The core of the GEMBA methodology constitutes the description of a dynamic EROI function over the whole production cycle of an energy resource from initial development, through maturation to decline in production, in the case of non-renewable resources, or to the technical potential in the case of renewable resources. Using the GEMBA methodology, the global energy-economy system is identified as a self-regulating system. The self-regulating behaviour acts to constrain the amount of total primary energy supply that the system can produce under a renewable-only regime. A number of analyses are conducted to test the sensitivity of the system to such changes as: an increase of the technical potential of renewable resources; technological breakthroughs which would significantly increase the EROI of renewable resources; a decrease in the capital intensity of renewable resources and; an increase in the energy intensity of the economy, A statistical analysis reflecting the wide range of values of both the estimates of EROI and technical potentials of renewable energy sources has also been undertaken using a Monte Carlo approach. The results from the modelling suggest that not all levels of energy demand projected by the WEA can be supplied by an energy system running solely on renewable energy. The Monte Carlo analyses suggest that reduction in total energy yield over current (2010) levels might occur with a 20-30% possibility. The middle and high growth scenarios from the WEA are greater than 95% of all scenarios modelled, hence seem unlikely to be sustained by an energy system running solely on renewable energy. This finding has implications for the future direction of both engineering and technology research as well as for energy policy. These implications are discussed.

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Water utilities are facing pressure to continue to provide high-quality potable water in an increasingly energy constrained world; managing the ageing infrastructure that exists in many countries is a challenge in and of itself, but recently this has been coupled with political and public attention to the environmental impacts of the distribution system. Utility managers need to take a holistic approach to decision-making in order to determine all of the impacts of their plans. The intention of this thesis is to present a set of considerations for utility planners and managers to provide clarity to the trade-offs associated with any pipe replacement decision. This research has examined the energy relationships between operational energy reduction and the embodied energy tied to replacing deteriorated pipes in water distribution networks. These relationships were investigated through the development and application of a life-cycle energy analysis (LCEA) for three different pipe replacement schedules developed with the intent to reduce leakage in the system. The results showed that the embodied energy for pipe replacement is significant even when compared against the large amount of energy required to operate a large-scale water utility. The annual operational energy savings of between 8.9 and 9.6 million kWh achieved by 2070 through pipe replacement comes at a cost; 0.88-2.05 million kWh/mile for replacement with ductile iron pipes with diameters of 6” to 16” respectively. This imbalance resulted in a maximum energy payback period of 17.6 years for the most aggressive replacement plan in the first decade. Some of the assumptions that were used to complete the LCEA were investigated through a sensitivity analysis; specific factors that were numerically queried in this chapter include the break rate forecasting method, pumping efficiency, the leakage duration and the flow rate per leakage event. Accurate accounting of energy requirements for pipe replacement will become even more important as energy and financial constraints continue to increase for most water utilities, this thesis provides guidance on some of the complex relationships that need to be considered. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-08-21 16:51:18.963

In this paper we develop a finite-difference scheme to approximate radially symmetric solutions of a dissipative nonlinear modified Klein-Gordon equation in an open sphere around the origin, with constant internal and external damping coefficients and nonlinear term of the form G' (w) = w ^p, with p an odd number greater than 1. We prove that our scheme is consistent of quadratic order, and provide a necessary condition for it to be stable order n. Part of our study will be devoted to study the effects of internal and external damping.

This study deals with the thermodynamic analysis of a molten carbonate fuel cell (MCFC) hybrid system to determine its efficiencies, irreversibilities and performance.The analysis includes a performance investigation of a typical molten carbonate fuel cell stack, an industrial MCFC hybrid system, and an MCFC hybrid system deployed by Enbridge. A parametric study is performed to examine the effects of varying operating conditions on the performance of the system. Furthermore, thermodynamic irreversibilities in each component are determined and an optimization of the fuel cell is conducted. Finally, a simplified and novel method is used for the cost analysis of the Enbridge MCFC hybrid system.An exergy analysis of the hybrid MCFC systems demonstrates that overall efficiencies of up to 60 % are achievable. The maximum exergy destruction was found in components in which chemical reactions occur. In addition, the turboexpander is one of the major contributors to the overall exergy destruction of the system. The cost analysis of the Enbridge system illustrates that by merging the importance of “green” energy and rising costs of carbon offsets, this new technology could be a promising solution and substitute for future energy supply. / UOIT

Accurate modeling of energy flows in buildings is necessary for optimization of mechanical systems, and architectural designs and components. One specific process which has been studied little is that of forced convection on the interior surfaces of window assemblies, which is present in the majority of newly constructed commercial buildings. To this end, energy flows associated with a specific Heating Ventilation and Air-Conditioning (HVAC) configuration- a floor register near a glass curtain wall with or without Venetian blinds- are analyzed experimentally and partially described with accepted theory. Natural convection at the same surface is analyzed as well, both to establish a baseline and to experimentally validate the experimental setup. A 60 cubic meter environmental chamber with precisely controlled interior conditions and electrical resistance heating panels is employed to study heat transfer at the interior surfaces of a building’s envelope. Convection heat transfer processes for various blind angles, HVAC regimes, surface temperatures, and window sizes are examined. Results show that convection at window and blind surfaces is highly dependent on blind angle, supply temperature and flow rate, moderately dependent on room-supply air temperature difference and HVAC regime, and weakly dependent on surface-supply air temperature difference. A simplified model of convection heat transfer in this particular situation is proposed for easy implementation in energy modeling software. / text

Résumé : Ce projet fait partie du projet MFERD (Magnésium Front End Research and Development) qui vise à développer les technologies permettant de rendre les alliages de Magnésium (Mg) comme un principal matériau structural pour les voitures (aujourd'hui essentiellement constituées d'acier quatre fois plus lourd que le Mg) afin d'en réduire leur masse pour des raisons environnementales et sécuritaires. Dans ce travail de maîtrise nous avons regardé la partie acoustique dans le cas d'un tablier (structure métallique derrière le tableau de bord) en magnésium. En effet, le confort acoustique à l'intérieur des voitures est devenu un argument de marketing d'une grande importance. Le tablier en séparant le compartiment moteur, source de bruit, de l'habitacle, joue un rôle important dans l'isolation acoustique de l'intérieur de la voiture. Ainsi le passage d'un tablier en acier à un tablier en Mg ne doit pas entraîner une baisse de performance. Dans ce travail, nous avons d'abord effectué une revue de la littérature sur les types de traitements acoustiques utilisés dans l'industrie automobile ainsi que des différentes techniques de leur modélisation. Nous avons ensuite comparé les performances acoustiques du tablier en Mg sur lequel on a appliqué des traitements classiques (à une couche, deux couches et trois couches) à celles des tabliers en acier et en aluminium et ce, à masse surfacique, raideur et/ou fréquences de résonnances égales. Finalement nous avons optimisé différents concepts de traitements acoustiques innovants appliqués sur le tablier en Mg en vue d'avoir des performances acoustiques semblables ou supérieures à celles du tablier en acier classique. L'optimisation s'est faite à partir d'un modèle SEA (Statitical Energy Analysis) couplé à un code d'optimisation basé sur un algorithme génétique||Abstract : This work is part of the MFERD (Magnesium Front End Research and Development) project which goal is to develop enabling technologies for the use of magnesium alloys as a principal structural material for cars (mainly made in steel which is four time heavier than magnesium) in order to reduce their mass for both, environmental and security concerns. In this work we have focused on the acoustic part, in the case of a magnesium alloy dash panel. The dash board, by separating the engine compartment from the interior cabin, plays a critical role in the insulation of the car interior. Since the acoustic comfort inside the car has become a marketing argument of great importance, the passage from steel to magnesium dash panel should not deteriorate acoustic performances. In this work, we first conducted a literature review on the types of acoustic treatments used in the automotive industry as well as various techniques of their modeling. We then compared the acoustic performances of a Mg dash with attached traditional acoustic treatments (single-layer, two layers and three layers) to those of a steel and aluminum dash panels with the same mass density, stiffness and/or frequency of resonances. Finally, we optimized different concepts of innovative sound packages applied on the Mg dash panel to achieve a noise performance similar or superior to those of a conventional steel dash. The optimization was done using a SEA (Statitical Energy Analysis) model, coupled with an optimization code based on a genetic algorithm.

In this paper we consider a radially symmetric nonlinear Dirichlet problem in a ball, where the nonlinearity is "superlinear" and "superlinear with jumping."

Master of Science / Department of Architectural Engineering / Charles L. Burton / An energy analysis was performed on a Midwestern residence to evaluate its performance based on energy use. A model of the actual house was replicated using eQuest and adjusted until its projected utility bills matched the actual yearly bills. This model was used to gauge how potential improvements made to the envelope and HVAC systems lowered the energy use. The results were documented after each improvement the feasible options were considered. The top alternatives were then combined to see how much money could be saved through renovating an existing home or through constructing a new residence. The overall goal of this report was to use the resulting improvement data as a reference for homeowners or home builders who are interested in conserving energy and money through residential improvements.