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This thesis investigates the feasibility of converting spent oil and gas wells for use in geothermal power generation. A novel approach to heat exchange with the ground was proposed whereby two directionally drilled (L-shaped) wells are connected to create a continuous loop. A Computational Fluid Dynamics (CFD) model was developed that simulates flow through the connected wells and the associated heat exchange with the ground. The model consisted of a coupled fluid-solid domain; 1D fluid flow was explicitly coupled to the 2D cylindrical solid domain using a convection boundary condition. Temperatures in the solid domain were resolved using an Alternating Direction Implicit (ADI) solver, which suited the largely unidirectional nature of the heat transfer problem. Fluid temperatures were solved for using a Tri-Diagonal Matrix Algorithm (TDMA). The results from a series of simulations demonstrated that geothermal power generation from abandoned wells is feasible under certain conditions. The findings of this research show that the correct selection of a well, considering geothermal gradient, well diameter, and ambient temperatures (impacting the inlet temperature), will significantly influence the level of power production. Further, the simulations show that it is necessary to optimize the flow rate for the given well conditions. The research indicates that the addition of insulation to a portion of the system can lead to modest improvements in power when the system is operated continuously. In contrast, it was found that insulation was necessary for the viability of intermittent use, which would allow the system to meet the demand for peak power generation. The simulations demonstrated that the proposed system could produce approximately 200 kW to 300 kW of electricity. / Thesis / Master of Applied Science (MASc)

Thermoelectric materials are playing a larger role in the global effort to develop diverse, efficient, and sustainable energy technologies: primarily through power-generating thermoelectric modules. The principal components of thermoelectric modules are solid-state thermoelectric materials – typically heavily doped semiconductors – that convert heat directly into electricity. However, this conversion efficiency is too low to supplant traditional energy technologies – severely limiting the distribution of clean and sustainable thermoelectric energy technologies. Efforts to enhance thermoelectric efficiency, which have been underway for decades, have been slow to realize appreciable gains in thermoelectric efficiency. However, a key advance in improving efficiency – the New Paradigm in thermoelectric material research – has been the development of thermoelectric nanocomposites. Thermoelectric nanocomposites show improved efficiency; however, they are often synthesized from highly toxic elements via energetically intense and costly synthesis procedures. Therefore, this research focuses on the discovery and development of a novel procedure for synthesizing thermoelectric nanocomposites – attrition enhanced nanocomposite synthesis – from open cage-like skutterudite-based materials. With further optimization, high-performance power-generating thermoelectric materials can be produced via this technique. Therefore, attrition-enhanced nanocomposite synthesis may play a small, though instrumental, role in achieving sustainable electrical power. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Jan. 6, 2012 - Jan. 6, 2013

Notre société évolue constamment et se positionne vis-à-vis du monde qui l’entoure. Cette évolution la pousse à se réorganiser atour d’énergie provenant de source locale et renouvelable. Pour ces raisons, il semble pertinent de concevoir une évolution possible de la méthanisation par des unités localisées. On parle alors de micro-méthanisation à l’échelle urbaine. La rédaction de cette thèse a ainsi eu pour objectif d’apporter des éléments de réponse quant à la question de la faisabilité d’intégrée cette micro-méthanisation dans des quartiers. Pour cela, il a été réalisé : i) Une analyse des retours d’expérience issus de villes porteuses de projet de méthanisation urbaine. ii) Une approche expérimentale, dans le but d’obtenir un processus de méthanisation des déchets urbains à l’échelle laboratoire. iii) Ces données d’entrée ont ensuite permis l’établissement d’un modèle de valorisation des déchets dans un quartier. Ces résultats mettent en avant la nécessité d’une approche systémique afin de pouvoir intégrer la méthanisation dans un quartier. Ils permettent de plus, de recommander l’utilisation de certains procédés et l’emploie de déchets, afin d’améliorer la mise en œuvre du processus dans l’espace urbain. Dans des conditions définies la méthanisation urbains est possible et stable dans le temps. De plus, le bilan énergétique s’avère bénéfique pour le quartier. On note que l’énergie ainsi produite, l’est majoritairement sous forme de chaleur ce qui met en avant l’intérêt d’un processus intégré, proche des habitations. / Our society is constantly evolving and positioning itself in relation to the world around it. This evolution pushes it to reorganize itself around energy from local and more renewable sources. For these reasons, it seems appropriate to design a possible evolution of anaerobic digestion (AD) by localized units. This is referred to a micro-AD at urban scale. The purpose of this thesis was to provide some answers to the question of the feasibility of integrating this micro-AD into a neighbourhood.To this end, it was carried out: i) An analysis of feedback from cities with urban AD projects. ii) An experimental approach, with the aim of obtaining a stable AD process of urban waste atlaboratory scale. iii) These input data then made it possible to establish a waste recovery model in a district. These results highlight the need for a systemic approach in order to be able to integrate AD in a neighbourhood. They also make it possible to recommend processes and wastes, in order to improve the implementation of the process in urban areas. Under defined conditions, urban AD is possible and stable over time. In addition, the energy balance is beneficial for the district. It should be noted that the energy thus produced is mainly in the form of heat, which highlights the importance of an integrated process, close to homes.

Healthcare is one of the most energy-intensive industries because of its 24 hour-a-day and 7-days-a-week operation model. Climate change, due to environmental pollution, has increased the incidence of respiratory disease, cardiovascular disease, and cancer, which further overload the financial burden of our healthcare system. The National Health Service Sustainable Development Unit suggested that a sustainable healthcare sector also requires using their resources in an efficient and responsible way. Hong Kong public hospitals are facing this problem along with high energy expenditure. The purpose of this qualitative, multiple site case study was to explore strategies for Hong Kong's public hospital leaders to develop and implement a sustainable program to reduce energy consumption. A purposive sample consisted of five local public hospital leaders that had successfully implemented a sustainable energy at their hospitals and received the 2014 Certificate of Merit of The Hong Kong Awards for Environmental Excellence. Semistructured interviews and document reviews were the data analysis methods for this study. The findings from the data analysis suggested that five major themes arose from the data: (a) external and internal driving forces, (b) leadership, (c) governance, (d) building a sustainable culture, and (e) performance measures. The recommendations of this study may lead to improving the use of energy in an efficient and responsible manner at the local public hospitals, reducing the hospital energy consumption cost, and reducing the disease incidences caused by environmental pollution.

The risk for climate change is a growing concern for theglobal society. According to what is known as the Kyoto Protocol,developed countries have committed themselves to reduce theirgreenhouse gas (GHG) emissions. The purpose of this thesis hasbeen to analyse opportunities for CO2 reductions in Swedish pulpand paper mills. The pulp and paper industry accounts forsignificant shares of the Swedish utilisationof both electricityand, in particular, biomass fuels. In this thesis, it has been agoal to focus not only on the technical potential of alternativesfor CO2 reductions in the energy systems of pulp and paper mills,but also on analysing the costeffectiveness of the studiedmeasures. Moreover, the analysis has covered questions concerningthe capacity and willingness among the actors involved with thepulp and paper mills’energy systems to realise CO2reduction potentials. A broad techno-economical evaluation of available technologiesfor increased power production as well as more efficient energyutilisation is carried out. Furthermore, a more indepth analysisof pulp mill-based biomass energy with CO2 removal and permanentsequestration (BECS) is presented. An evaluation is made of thepotential for pulp and paper production with a negative CO2balance through the implementation of BECS. In recent yearsoutside suppliers, mainly energy service companies (ESCOs), havebegun to operate energy facilities in some Swedish pulp and papermills. Based on interviews with managers from pulp and papercompanies and ESCOs, the main driving forces behind theincreasing co-operation as well as the opportunities and riskswith energy related co-operation are presented. Furthermore, the technical possibility of carbon-negativitythrough the implementation of BECS is discussed in relation tocarbon management on both corporate and global levels. The extentto which CO2-reducing measures in pulp and paper mills arerealised will have an impact on Sweden’s capacity to reachCO2 reduction targets. Whether or not technologies for CO2capture and sequestration are developed and implemented inSwedish pulp mills has a very large impact on the size ofSweden’s long-term CO2 reduction potential. Moreover, thedevelopment of business and competence focus in pulp and papercompanies and ESCOs suggests that cooperation will become ofincreasing importance for future sustainable industrial energymanagement. <b>Keywords:</b>CO2 reduction, pulp and paper industry, energysystem, biomass, CO2 capture and sequestration, black liquor,gasification, power production, outsourcing, sustainable energymanagement

This thesis analyses a specific type of energy usage system, “energy usage in hotels”, and how this system behaves. In order to evaluate the current state of energy use in hotels, an energy audit questionnaire was developed and conducted among 31,5% of hotels on the Adriatic coast. The energy audit was used as a tool to set a benchmark for energy consumption in hotels and to identify opportunities for increased energy efficiency measures in HVAC systems. The analysis has shown that the average energy consumption in hotels on the Adriatic coast is in the range of 159 to 180 kWh/m2 and 162 to 225 kWh/m2 for seasonal and non seasonal hotels respectively. In order to establish a relationship between different independent variables in the hotels (total floor area and number of rooms) and dependent variables, such as electricity and oil consumption, mathematical statistical methods, such as correlation and regression analysis, were implemented. The objective of this thesis was also to develop - from an energy, environmental and economical points of view - a methodology for the design and retrofit of HVAC systems in the hotels on the Adriatic coast. The methodology named HOTECO is based on a system thinking approach. With respect to the technological aspects, the first step was to analyse conventional HVAC system designs and to compare it with the three most promising alternative HVAC systems utilizing renewable energy sources for a typical hotel. Computer modelling in TRNSYS was used to assess energy consumption. TRNSYS software has been used for simulations for a number of years, is internationally recognized, and has been validated and verified. It was concluded that energy and environmental savings in hotels on the Adriatic coast could be achieved using readily available technologies. The HOTECO methodology also demonstrated a framework that supports decision making iv regarding system selection and operational strategies to limit environmental impact from HVAC systems in hotels. Four scenarios for energy consumption in hotels on the Adriatic coast with regards to current state of energy systems and improved retrofit solutions utilizing renewable energy source were given. / QC 20100929