The increasing share of renewable energies in the power sector influences the economic viability of investments in new conventional power plants. Many studies have investigated these issues by considering power plant operation or the long-term development of the power plant fleet. However, power plant decommissioning, investment and operation are intrinsically linked. This doctoral thesis therefore presents a modelling framework for an integrated consideration of power plant decommissioning, investment and operation. In a case study focusing on Germany, the effects of the integration of renewable energies on power plant decommissioning, investment and operation are evaluated in the context of different assumptions regarding the remaining lifetime of nuclear power plants. With regard to the use of nuclear power, a phase-out scenario and a scenario with lifetime extension of nuclear power plants (by on average 12 years) are considered. The results show that static decommissioning (i.e. considering fixed technical lifetimes) underestimates the capacity available in the power sector in the scenario without lifetime extension since retrofit measures (versus decommissioning) are not taken into account. In contrast, capacity available in the case of nuclear lifetime extension is overestimated since mothballing (versus regular operation) is not considered. If the impact on decommissioning decisions of profit margins accrued during power plant operation are considered (“dynamic decommissioning”), the electricity price reduction effect due to a lifetime extension is reduced by more than half in comparison to static decommissioning. Scarcity situations do not differ significantly between the scenarios with and without lifetime extension with dynamic decommissioning; in contrast, there is a significantly higher need for imports without lifetime extension with static decommissioning. The case study demonstrates that further system flexibility is needed for the integration of renewable energies. It can be further concluded that the share of flexible power plants is higher with the phase-out of nuclear power plants. With regard to the decommissioning dynamics, the phase-out can be considered as beneficial for the economic viability of fossil power plants. Furthermore, the phase-out does not, overall, lead to environmental disadvantages in the medium term, but may be beneficial in the long run since lock-in effects are avoided. Further research is required with regard to the consideration of future flexibility options and a new market design. / Der steigende Anteil erneuerbarer Energien beeinflusst die Wirtschaftlichkeit von Investitionen in neue konventionelle Kraftwerke. Zahlreiche Studien haben diese Aspekte in Bezug auf den Kraftwerksbetrieb oder die langfristige Entwicklung des Kraftwerksparks untersucht. Stilllegungen, Investitionen und Betrieb im Kraftwerkspark bedingen jedoch einander. Aus diesem Grund wird in dieser Doktorarbeit ein Modellierungsansatz für eine integrierte Betrachtung von Kraftwerksstilllegung, -investition und -betrieb vorgestellt. In einer Fallstudie für Deutschland werden die Auswirkungen einer Integration erneuerbarer Energien auf Kraftwerksstilllegung, -investition und -betrieb im Zusammenhang mit unterschiedlichen Annahmen über die Restlaufzeit von Kernkraftwerken untersucht. Bezogen auf die Nutzung der Kernenergie wird hierbei ein Ausstiegsszenario sowie ein Laufzeitverlängerungsszenario (Verlän-gerung der Laufzeit um durchschnittlich 12 Jahre) betrachtet. Die Ergebnisse zeigen, dass die statische Stilllegung (d.h. die Betrachtung fester technischer Lebensdauern) im Fall eines Verzichts auf die Laufzeitverlängerung die im Kraftwerkspark verfügbare Leistung unterschätzt, da Retrofit-Maßnahmen (im Vergleich zur Stilllegung) nicht berücksichtigt werden. Die verfügbare Leistung im Falle einer Laufzeitverlängerung wird dagegen überschätzt, da die Möglichkeit der Kaltreserve (im Vergleich zum regulären Betrieb) vernachlässigt wird. Werden die Rückwirkungen der im Betrieb erwirtschaftbaren Deckungsbeiträge auf Stilllegungsentscheidungen (“dynamische Stilllegung”) betrachtet, so wird der strompreissenkende Effekt durch die Laufzeitverlängerung im Vergleich zur statischen Stilllegung mehr als halbiert. Knappheitssitutationen unterscheiden sich nicht wesentlich mit und ohne Laufzeitverlängerung im Fall der dynamischen Stilllegung, während bei statischer Stilllegung ohne Laufzeitzeitverlängerung ein deutlich größerer Importbedarf besteht. Die Fallstudie zeigt, dass weitere Systemflexibilitäten für die Integration erneuerbarer Energien benötigt werden. Der Anteil flexibler Kraftwerke ist größer im Fall des Kernenergieausstiegs. Der Kernenergieausstieg wirkt sich in Bezug auf die Stilllegungsdynamik positiv auf die Wirtschaftlichkeit fossiler Kraftwerke aus. Insgesamt führt der Kernenergieausstieg zu keinen mittelfristig nachteiligen Umwelteffekten, er kann sich jedoch langfristig positiv auswirken, da Lock-in-Effekte vermieden werden. Es besteht weiterer Forschungsbedarf in Bezug auf die Berücksichtigung künftiger Flexibilitätsoptionen und ein neues Marktdesign.

[pt] O Rio de Janeiro é uma cidade de alta densidade demográfica em uma situação geográfica excepcional, entre o mar, as montanhas e diversas lagoas. Uma parcela de sua população, de aproximadamente 6 milhões de habitantes, vive em edifícios de apartamentos. Em muitos bairros não há mais terrenos disponíveis para novas edificações. A construção sustentável é necessária para redução de consumos e desperdícios, assim como a fundamental atenção a aspectos de conforto ambiental e sociais (o morador). Visando a melhoria da qualidade de vida e para atingir um estágio de sustentabilidade será necessário pensar em como aperfeiçoar os edifícios e quadras existentes. Na cidade do Rio de Janeiro há diversos proprietários e locatários, sendo importante elaborar uma estratégia específica para desenvolver uma renovação do parque construído. A presente tese aborda: os edifícios residenciais no Rio de Janeiro (e a legislação), a construção sustentável, a renovação de edifícios e quadras, recomendações para projetos de acordo com as características climáticas e verificações sobre as condições existentes (físicas, ambientais e sociais). Foi desenvolvido um estudo de caso em uma quadra típica no famoso e de alta densidade demográfica bairro de Copacabana (96 porcento de seus moradores vivem em apartamentos, sendo 1/3 com mais de 60 anos) que teve praticamente todos os seus prédios e quadras construídos entre 1940 e 1960 com características semelhantes como: estrutura em concreto, edifícios de 10 e 12 pavimentos e com pouco ou nenhum afastamento entre si. / [en] Rio de Janeiro is a very dense city in an exceptional geography situation between the sea, the mountains and some lakes. The population of six million inhabitants only in the municipality area lives mainly in apartments buildings. In some neighborhoods there are no empty sites for new constructions. Sustainable construction is a necessary step to reduce the consumption and the waste, and also the focus in the comfort conditions and social aspects (the dwellers). To improve the quality of living and achieve the environmental goals it is necessary to think how to upgrade the quality of existing buildings and blocks. In Rio de Janeiro each building has different owners and dwellers, and it will be important to work in a specific strategy to develop the building stock renovation. This thesis involves: apartment buildings in Rio de Janeiro (including the legislation), sustainable construction, renovation (refurbishment) of buildings and blocks, design recommendations according to the climatic conditions in Rio de Janeiro, and the verification of apartment building conditions (physical, environmental and social). One case study in a regular block of a very dense and famous neighborhood named Copacabana (96 percent of dwellers in this neighborhood live in apartments and 1/3 is older than 60 years old) was developed. Copacabana has almost all the buildings and blocks built during the 1940 and 1960 decades with common features like: concrete structure, buildings with 10 to 12 floors, and no distance between them.

The diploma thesis deals with the issue of replacement of non-ecological refrigerant R22 according to the requirements of relevant juristic regulations and of subsequent influence of this replacement to the efficiency of air conditioning systems. The theoretical part is focused on proceeding processes in thermodynamic cycles and during heat transfer, then determines calculation of cooling and heating factor in context with experimental measurement. The experimental measurement utilizes to the assessment of operation of heat pump after refrigerant replacement and it is source for the composion of economical evaluation of alternative solutions due to the particular choice of refrigerant replacement.

Legally binding targets set by the UK government to reduce carbon emissions by 2050 mean it is imperative that the efficiency of the UK housing stock is improved. Housing currently contributes over 30% of the UK s total carbon emissions and a large proportion of the current stock will still exist in 2050. There is therefore a need to retrofit this existing stock with energy saving measures, as the savings from new builds will not be adequate to meet the stringent carbon reduction targets. Whilst technologies to facilitate energy saving retrofit are available, there has been a low uptake from householders in the UK, in part due to the lack of consideration of user requirements within the design of these technologies. To investigate this issue further, this thesis considers two main questions: How can the design of energy saving measures and the process of retrofit of the existing UK housing stock be improved through the use of user centred design (UCD) and How can UCD methods be applied to the research and development process for energy saving measures in order to improve the outcome? Through the research, it became clear that in order to answer these questions, it would be necessary to work across disciplines and therefore a third Research Question was posed; How can UCD facilitate working across disciplines in the context of an energy research project? The results provide evidence of how UCD can effectively improve the design and development process of energy saving technologies, the process of retrofit and the practice of cross-disciplinary working within a research environment. The research is novel in several ways: firstly, the UCD process has been applied in the area of domestic retrofit, giving new insights into the barriers and opportunities to retrofit; secondly, home improvement has been investigated by viewing the home as a complete, interacting system, using novel methods; thirdly, a set of UCD specifications have been created to inform the design of heat pumps, a specific domestic energy saving technology, and finally, enhancements to the UCD process are made for use within an energy technology project, together with the development of six principles for effective cross-disciplinary working and conceptualisation of the bridge building role which the UCD practitioner fulfills.

The effectiveness of seismic retrofitting applied to enhance seismic performance was assessed for a five-story reinforced concrete (RC) flat-slab building structure in the central United States. In addition to this, an assessment of seismic fragility that relates the probability of exceeding a performance level to the earthquake intensity was conducted. The response of the structure was predicted using nonlinear static and dynamic analyses with synthetic ground motion records for the central U.S. region. In addition, two analytical approaches for nonlinear response analysis were compared. FEMA 356 (ASCE 2000) criteria were used to evaluate the seismic performance of the case study building. Two approaches of FEMA 356 were used for seismic evaluation: global-level and member-level using three performance levels (Immediate Occupancy, Life Safety and Collapse Prevention). In addition to these limit states, punching shear drift limits were also considered to establish an upper bound drift capacity limit for collapse prevention. Based on the seismic evaluation results, three possible retrofit techniques were applied to improve the seismic performance of the structure, including addition of shear walls, addition of RC column jackets, and confinement of the column plastic hinge zones using externally bonded steel plates. Finally, fragility relationships were developed for the existing and retrofitted structure using several performance levels. Fragility curves for the retrofitted structure were compared with those for the unretrofitted structure. For various performance levels to assess the fragility curves, FEMA global drift limits were compared with the drift limits based on the FEMA member-level criteria. In addition to this, performance levels which were based on additional quantitative limits were also considered and compared with FEMA drift limits.

Mitigation of the blast risk associated with terrorist attacks and accidental explosions threatening critical infrastructure has become a topic of great interest in the civil engineering community, both in Canada and abroad. One method of mitigating blast risk is to retrofit vulnerable structures to resist the impulsive effects of blast loading. A comprehensive re-search program has been undertaken to develop fibre reinforced polymer (FRP) retrofit methodologies for structural and non-structural elements, specifically reinforced concrete slabs and walls, subjected to blast loading. The results of this investigation are equally valid for flexure dominant reinforced concrete beams subject to blast effects. The objective of the research program was to generate a large volume of research data for the development of blast-resistant design guidelines for externally bonded FRP retrofit systems. A combined experimental and analytical investigation was performed to achieve the objectives of the program. The experimental program involved the construction and simulated blast testing of a total of thirteen reinforced concrete wall and slab specimens divided into five companion sets. These specimens were subjected to a total of sixty simulated explosions generated at the University of Ottawa Shock Tube Testing Facility. Companion sets were designed to study one- and two-way bending, as well as the performance of specimens with simply-supported and fully-fixed boundary conditions. The majority of the specimens were retrofitted with externally bonded carbon fibre reinforced polymer (CFRP) sheets to improve overall load-deformation characteristics. Specimens within each companion set were subjected to progressively increasing pressure-impulse combinations to study component behaviour from elastic response up to inelastic component failure. The blast performance of companion as-built and retrofitted specimens was quantified in terms of measured load-deformation characteristics, and observed member behaviour throughout all stages of response. The results show that externally bonded FRP retrofits are an effective retrofit technique to improve the blast resistance of reinforced concrete structures, provided that debonding of the composite from the concrete substrate is prevented. The test results also indicate that FRP retrofitted reinforced concrete structures may survive initial inbound displacements, only to failure by moment reversals during the negative displacement phase. The experimental test data was used to verify analytical techniques to model the behaviour of reinforced concrete walls and slabs subjected to blast loading. The force-deformation characteristics of one-way wall strips were established using inelastic sectional and member analyses. The force-deformation characteristics of two-way slab plates were established using commonly accepted design approximations. The response of all specimens was computed by explicit solution of the single degree of freedom dynamic equation of motion. An equivalent static force procedure was used to analyze the response of CFRP retrofitted specimens which remained elastic after testing. The predicted maximum displacements and time-to-maximum displacements were compared against experimental results. The analysis indicates that the modelling procedures accurately describe the response characteristics of both retrofitted and unretrofitted specimens observed during the experiment.

The purpose of this research is to determine the average energy intensity of multi-unit residential buildings (MURBs) in Toronto, and evaluate whether certain building characteristics influence energy intensity. This information is particularly important in the Toronto market. Relative to the city’s population, Toronto has an unusually high proportion of MURBs with more than half of residential dwellings in apartment buildings. Additionally, Toronto MURBs are significant consumers of energy and produce an estimated 1.3M tonnes of CO2e each year. The ultimate goal is to assess the most efficient building retrofit measures. Energy consumption data for Toronto MURBs were collected and weather normalized. Correlations between the energy data and the building characteristics were examined. Window characteristics and heating system type were found to have the most significant influence on energy intensity. Establishing energy consumption characteristics of MURBs is the first step towards improving the energy efficiency of Toronto’s MURBs stock.

The purpose of this research is to determine the average energy intensity of multi-unit residential buildings (MURBs) in Toronto, and evaluate whether certain building characteristics influence energy intensity. This information is particularly important in the Toronto market. Relative to the city’s population, Toronto has an unusually high proportion of MURBs with more than half of residential dwellings in apartment buildings. Additionally, Toronto MURBs are significant consumers of energy and produce an estimated 1.3M tonnes of CO2e each year. The ultimate goal is to assess the most efficient building retrofit measures. Energy consumption data for Toronto MURBs were collected and weather normalized. Correlations between the energy data and the building characteristics were examined. Window characteristics and heating system type were found to have the most significant influence on energy intensity. Establishing energy consumption characteristics of MURBs is the first step towards improving the energy efficiency of Toronto’s MURBs stock.

Mitigation of the blast risk associated with terrorist attacks and accidental explosions threatening critical infrastructure has become a topic of great interest in the civil engineering community, both in Canada and abroad. One method of mitigating blast risk is to retrofit vulnerable structures to resist the impulsive effects of blast loading. A comprehensive re-search program has been undertaken to develop fibre reinforced polymer (FRP) retrofit methodologies for structural and non-structural elements, specifically reinforced concrete slabs and walls, subjected to blast loading. The results of this investigation are equally valid for flexure dominant reinforced concrete beams subject to blast effects. The objective of the research program was to generate a large volume of research data for the development of blast-resistant design guidelines for externally bonded FRP retrofit systems. A combined experimental and analytical investigation was performed to achieve the objectives of the program. The experimental program involved the construction and simulated blast testing of a total of thirteen reinforced concrete wall and slab specimens divided into five companion sets. These specimens were subjected to a total of sixty simulated explosions generated at the University of Ottawa Shock Tube Testing Facility. Companion sets were designed to study one- and two-way bending, as well as the performance of specimens with simply-supported and fully-fixed boundary conditions. The majority of the specimens were retrofitted with externally bonded carbon fibre reinforced polymer (CFRP) sheets to improve overall load-deformation characteristics. Specimens within each companion set were subjected to progressively increasing pressure-impulse combinations to study component behaviour from elastic response up to inelastic component failure. The blast performance of companion as-built and retrofitted specimens was quantified in terms of measured load-deformation characteristics, and observed member behaviour throughout all stages of response. The results show that externally bonded FRP retrofits are an effective retrofit technique to improve the blast resistance of reinforced concrete structures, provided that debonding of the composite from the concrete substrate is prevented. The test results also indicate that FRP retrofitted reinforced concrete structures may survive initial inbound displacements, only to failure by moment reversals during the negative displacement phase. The experimental test data was used to verify analytical techniques to model the behaviour of reinforced concrete walls and slabs subjected to blast loading. The force-deformation characteristics of one-way wall strips were established using inelastic sectional and member analyses. The force-deformation characteristics of two-way slab plates were established using commonly accepted design approximations. The response of all specimens was computed by explicit solution of the single degree of freedom dynamic equation of motion. An equivalent static force procedure was used to analyze the response of CFRP retrofitted specimens which remained elastic after testing. The predicted maximum displacements and time-to-maximum displacements were compared against experimental results. The analysis indicates that the modelling procedures accurately describe the response characteristics of both retrofitted and unretrofitted specimens observed during the experiment.

The central focus of this dissertation is a seismic vulnerability assessment of retrofitted bridges. The objective of this work is to establish a methodology for the development of system level fragility curves for typical classes of retrofitted bridges using a probabilistic framework. These tools could provide valuable support for risk mitigation efforts in the region by quantifying the impact of retrofit on potential levels of damage over a range of earthquake intensities. The performance evaluation includes the development of high-fidelity three-dimensional nonlinear analytical models of bridges retrofit with a range of retrofit measures, and characterization of the response under seismic loading. Sensitivity analyses were performed to establish an understanding of the appropriate level of uncertainty treatment to model, assess, and propagate sources of uncertainty inherent to a seismic performance evaluation for portfolios of structures. Seismic fragility curves are developed to depict the impact of various retrofit devices on the seismic vulnerability of bridge systems. This work provides the first set of fragility curves for a range of bridge types and retrofit measures. Framework for their use in decision making for identification of viable retrofit measures, performance-based retrofit of bridges, and cost-benefit analyses are illustrated. The fragility curves developed as a part of this research will fill a major gap in existing seismic risk assessment software, and enable decision makers to quantify the benefits of various retrofits.