Energy demand for buildings has been rising during recent years. Increasing building energy consumption has caused many energy-related problems and environmental issues. The on-site community energy system application is a promising way of providing energy for buildings. Community energy system usage reduces the primary energy consumption and environmental effects of greenhouse gas (GHG) emissions compared to the implementation of the stand-alone energy systems. Furthermore, due to the increase in electricity price and shortage of fossil fuel resources, renewable energies and energy storage technologies could be great alternative solutions to solve energy-related problems. Generally, the energy system might include various technologies such as internal combustion engine, heat recovery system, boiler, thermal storage tank, battery, absorption chiller, ground source heat pump, heating coil, electric chiller, solar photovoltaics (PV) and solar thermal collectors, and seasonal thermal energy storage. The economic, technical and environmental impacts of energy systems depend on the system design and operational strategy. The focus of this thesis is to propose unified frameworks, including the mathematical formulation of all of the components to determine the optimal energy system configuration, the optimal size of each component, and optimal operating strategy. The proposed methodologies address the problems related to the optimal design of the energy system for both deterministic and stochastic cases. By the use of the proposed frameworks, the design of the energy system is investigated for different specified levels of GHG emissions ratio, and the purpose is to minimize the annual total cost. To account for uncertainties and to reduce the computational times and maintain accuracy, a novel strategy is developed to produce scenarios for the stochastic problem. System design is carried out to minimize the annual total cost and conditional value at risk (CVaR) of emissions for the confidence level of 95%. The results demonstrate how the system size changes due to uncertainty and as a function of the operational GHG emissions ratio. It is shown that with the present-day technology (without solar technologies and seasonal storage), the lowest amount of GHG emissions ratio is 37%. This indicates the need for significant technological development to overcome that ratio to be 10% of stand-alone systems. This thesis introduces novel performance curves (NPC) for determining the optimal operation of the energy system. By the use of this approach, it is possible to identify the optimal operation of the energy system without solving complex optimization procedures. The application of the proposed NPC strategy is investigated for various case studies in different locations. The usage of the proposed strategy leads to the best-operating cost-saving and operational GHG savings when compared to other published approaches. It has shown that other strategies are special (not always optimal) cases of the NPC strategy. Based on the extensive literature review, it is found that it is exceptionally complicated to apply the previously proposed models of seasonal thermal energy storage in optimization software. Besides, the high computational time is required to obtain an optimum size and operation of storage from an optimization software. This thesis also proposes a new flexible semi-analytical, semi-numerical methodology to model the heat transfer process of the borehole thermal energy storage to solve the above challenges. The model increases the flexibility of the storage operation since the model can control the process of the storage by also deciding the appropriate storage zone for charging and discharging. / Thesis / Doctor of Engineering (DEng)

The acceleration towards achieving a low carbon society has raised many challenges in the energy sector. The existing systems, highly dependent on fossil fuels, are not sustainable and recommendations are made to accelerate the transition by using more renewable and low-carbon sources of energy. By being responsible for over 70 % of the greenhouse gas emissions, cities or districts have a major role to play in this transition and present a large potential for implementation of renewable energy systems. The optimization of those systems and a better use of energy are crucial to reduce emissions and reach carbon neutrality. This study evaluates the potential of the implementation of three storage solutions for a decentralized energy system in a residential cluster in Ludvika, Sweden, equipped with photovoltaics panels. The first solution includes stationary batteries, the second includes a hydrogen storage solution and the third offers a hybrid solution from the two previous storages. Simulations were conducted using two numerical tools with an hourly resolution.The first scenario was conducted using Spine modelling tools, and the other simulations, including the cost analysis, were conducted on Excel with the support of Visual Basic for Applications. The comparison between the three solutions showed that the stationary batteries, blessed with a higher efficiency, offers the best results. The autonomy of the site, initially at 19.1 %, was raised to 22.8 % due to the batteries, and the system allowed to save up to 9.6 MW∙h per year. The investment price of the battery system was the highest of the three solutions. However, the payback period is reached in 20 years, within the average lifespan of the batteries and 10 years shorter than with the other solutions. The results also showed that the benefits of implementing a hydrogen storage solution were not visible as the excess in the photovoltaic production was not enough to cover the energy demand in a long-term period.

Du fait de la flexibilité énergétique qu'ils offrent et de leur potentiel de diminution des émissions de GES et de polluants, les réseaux de chaleur (RdC) sont un des leviers d'actions des politiques énergétiques locales en constante progression. Leur déploiement et/ou rénovation n'est pas qu'une question technico-économique classique, dans la mesure où ils sont au cœur d'un ensemble d'acteurs interconnectés, aux objectifs spécifiques, tous parties prenantes des politiques énergétiques locales. Dans ce contexte, les outils permettant à ces différents acteurs l'évaluation des actions liées aux RdC sont très importants. Ils doivent permettre l'évaluation de scénarios de conception, d'actions de rénovation, de performance et de suivi... Parmi les outils permettant ces évaluations, les approches par modélisation sont souvent trop spécifiques à une situation, un type de réseau un acteur... Le travail réalisé consiste à développer un outils de modélisation de RdC, offrant la flexibilité recherchée. "HeatGrid" permet de modéliser des architectures de réseaux variées. A chaque pas de temps, le fonctionnement du réseau est simulé grâce au formalisme de la programmation linéaire. Cet outil peut être utilisé en phase de conception ou d'exploitation d'un réseau. L'approche de modélisation permet d'évaluer et de comparer sous les aspects économiques, énergétiques et techniques d'un RdC sous différents scénarios. Plusieurs exemples sont simulés et analysés dans le but d'illustrer le potentiel du modèle. / Because of the energy flexibility that they offer and their potential to reduce GHG emissions, disctrict heating (DH) networks are a tool of local energy policies in constant progression. Their develpment and/or renovation is not only a classic technico-economical question, insofar as interconnected stakeholders of local energy policies, taking into account specific objectives, are concerned by DH networks. In this context, tools which enable these different stakeholders to evaluate actions related to DH networks are essential. They must be helpful for the assessment of renovation actions, the monitoring and the evaluation of performances....Among the tools that allow theses evaluations, the modelling approaches are often too specific to a situation, a type of network, a stakeholder... The work of the thesis consists in developing a DH modeling tool that has this desired flexibility. The proposed tool "HeatGrid" can model various network architectures. At each time step, the network running is simulated via linear programming formalism. This tool can be applied either at the design stage of a DH or at the operating stage. The model based approach enables the evaluation and comparison of economic, energy and technical aspects of the DH system in different scenarios. Several examples are simulated and analyzed in order to illustrate the potential of the model.

This thesis investigated application of the heat recovery ventilation using an exhaust air heat pump and a roof top photovoltaic (PV) system for a group of three multi-family houses located in Ludvika, Sunnansjö. The buildings in the existing condition have mechanical ventilation and a centralized heating system consists of a pellet boiler as the main source and an oil boiler as back up. Exhaust air heat pump (EAHP) has been known by the previous relevant researches as an effective solution to promote the energy efficiency in the buildings. Furthermore, reduction in PV cost has made the PV as a financially viable option to be contributed in supplying electricity demand. In this respect, this thesis aimed to calculate the potential of energy saving in the case study using the combination of EAHP and PV. For this purpose, the buildings and the proposed energy system were simulated to enable the comparison of energy demand before and after the renovation. The simulation was gradually progressed through several phases and each stage created the prerequisites of the next. Since the buildings were relatively similar in terms of boundary conditions, one of the buildings were initially modeled and the concluded space heating (SH) demand was extrapolated to the three buildings scope. The simulation of the building was done using 3dimensional thermal model offered by Trnsys3d. The primary results were also calibrated against the available annual fuel consumption data. In the second phase, a pre-developed TRNSYS model of the energy system was completed using the result of previous step as the total SH demand as well as the estimated domestic hot water (DHW) consumption from a stochastic model. This simulation produced the electricity demand profile of the heat pump when the heat pump provided the total heat demand. Subsequently, the electricity consumption of the flats and operational equipment were estimated using stochastic model and available monthly measurement, respectively. Since the feasibility and optimal placement of 74 𝑘𝑊 PV modules offered for these buildings had been already examined by the author in another study, the final simulation were performed in an hourly basis considering PV production and total electricity demand; i.e. EAHP, flats consumption and operational equipment. The results of the simulation showed that 21 % of total electricity demand during a year could be supplied by the proposed PV system even without any electrical storage, whereas 74 % of total yearly PV production is consumed by the local loads. The results also proved that removing old inefficient oil boiler and supplementing the pellet boiler with the combination of EAHP and PV could mitigate the annual purchased energy (including electricity and pellet) by approximately 40 % compared to the current condition.

With sharp climate goals to be climate neutral by 2045, Sweden needs to rapidly change the present energy system. The Swedish government has assigned Gotland as a pilot area for the energy transition, due to its geographical constrains as an island, and because of the major structural changes planned for Gotland’s energy supply and industrial establishment. These changes create the opportunity to build a more flexible, efficient, and robust energy system. To support the transition, IVL Swedish Environmental Research institute has initiated the GOT Heat project. This thesis contributes to the GOT Heat project by developing a GIS model that represent the heat sector of Gotland. The model has been developed in parallel with a TIMES model. The purpose of the GIS model is to be used as a heat atlas and to support the TIMES model of Gotland’s energy system by spatial visualization and knowledge. The GIS model was successfully developed and utilized to enhance the representation of Gotland’s energy system within the TIMES model. Data from Boverket, Lantmäteriet, Energimyndigheten and companies has been collected, processed for the development of the GIS model. The incorporation of spatial knowledge and visualization of the heat sector through the GIS model is expected to improve the overall outcomes of the TIMES model. The heat atlas also proved to be a valuable support tool, enabling the visualization of excess heat potentials within the heat sector. This visualization provides insights into potential opportunities for industrial and sector coupling, which would lead to more efficient utilization of excess heat.

Diese Arbeit geht der Frage nach, ob sich durch die stattfindende Transformation zu einem kohlenstoffarmen Energiesystem in Deutschland auch Marktchancen für innovative Marktteilnehmer, insbesondere für Speicherbetreiber, herausbilden. Die ökonomischen Effekte, die in Energiesystemen mit hohen Anteilen an variablen erneuerbaren Energien (vEE) auftreten, können durch deren Integrationskosten gemessen werden. Die wissenschaftlichen Untersuchungen in Bezug auf den zusätzlichen Speicher- bzw. Flexibilitätsbedarf für ein solches Energiesystem setzen häufig bei den Ungleichgewichten in der Systembilanz an. Den jeweiligen Methoden liegen jedoch unterschiedliche Annahmen und Rahmenbedingungen zu Grunde, sodass die Ergebnisse nur eingeschränkt miteinander verglichen werden können. Der stündlich schwankende Großhandelspreis an der Strombörse ist ein wichtiger Indikator, um den Flexibilitätsbedarf zu signalisieren. Viele Analysen legen historische oder auch prognostizierte Preiszeitreihen für eine Bewertung von Speicheroptionen zu Grunde. Jedoch wird dabei die Rückkopplung der Betriebsweise eines Energiespeichers auf die Marktpreise außen vor gelassen. In dieser Arbeit wird deshalb eine Methode entwickelt, um den Einfluss eines steigenden Marktvolumens an Speichern und anderen Flexibilitätsoptionen auf die Spotmarktpreise abzuschätzen. Untersucht wird der Einfluss des Speichereinsatzes auf die Stromnachfrage und die Spotmarktpreise in 2020 sowie 2030. Die hierfür zu definierenden Szenarien für den Strommarkt werden modellgestützt abgebildet und ausgewertet. Für die Beantwortung der Fragestellung werden techno-ökonomische Modelle, z.B. das Strommarktmodell MICOES zur Kraftwerkseinsatzplanung, das Modell DeSiflex zur Glättung der Residuallast durch integrierte Flexibilitätsoptionen sowie das Modell Arturflex zur Abschätzung der Arbitragegewinne durch Einsatz von Flexibilitätsoptionen am Spotmarkt, herangezogen.

Considerando que a duração do combate de judô pode variar entre poucos segundos até um período superior a 5 min, a caracterização da demanda fisiológica do combate na sua duração regulamentar e fracionada, assim como a relação dessas respostas com o nível de aptidão aeróbia e anaeróbia dos atletas é relevante para o aperfeiçoamento dos métodos de treinamento. Assim, o objetivo do presente estudo foi analisar a aptidão física, ações técnicas e respostas fisiológicas durante a luta de judô com diferentes durações. Para tanto, 12 atletas de judô foram submetidos a 10 sessões de avaliação. Nas duas primeiras sessões foram realizados quatro testes físicos para caracterização da aptidão aeróbia e anaeróbia dos membros superiores e inferiores. Nas demais sessões, os atletas foram submetidos a 15 combates simulados de judô (3 condições x 5 durações - 1, 2, 3, 4 e 5 min) com o mesmo oponente, em ordem aleatória e vendados quanto à duração do combate. Em uma das condições, os atletas simularam um combate real. Na segunda condição, os atletas lutaram usando um analisador de gases para mensurar o consumo de oxigênio, para a estimativa da contribuição dos sistemas de transferência de energia. Nessa condição foram impostas algumas adaptações de movimento. Para verificar se o uso do analisador de gases modificou as respostas obtidas, na terceira condição, os atletas lutaram com as mesmas adaptações, porém não usaram o equipamento. Em cada sessão foram conduzidos dois combates, intercalados por 60 min de recuperação. Foram quantificadas as respostas fisiológicas, perceptivas, de desempenho, de estrutura temporal e ações técnicas em todos combates. A comparação das variáveis dependentes foi realizada com uma análise de modelos mistos para medidas repetidas, seguida do post hoc de Bonferroni. As associações entre a aptidão aeróbia e anaeróbia com as variáveis do combate foram verificadas por meio da correlação de Pearson. Para todas as comparações pareadas significantes foi calculado o tamanho do efeito (d de Cohen). Em todas as análises foi adotado 5% como nível de significância. Os principais resultados demonstraram aumento da contribuição aeróbia com concomitante redução da contribuição dos sistemas anaeróbios com o transcorrer do combate, sendo a contribuição aeróbia superior à contribuição dos sistemas anaeróbios a partir do primeiro min de combate. O sistema anaeróbio lático contribuiu com a menor proporção do custo energético do combate de judô. As taxas de incremento das respostas fisiológicas e perceptivas por min de combate foram reduzidas com o transcorrer do combate, sendo as principais modificações observadas no início do combate, sugerindo que os atletas podem apresentar estratégia para modular seus esforços. Com o transcorrer do combate observou-se manutenção do tempo médio de esforço e ações aplicadas, porém houve aumento do tempo médio dos períodos de pausa. Após a realização do combate observou-se declínio da resistência muscular dinâmica dos membros superiores, manutenção da força isométrica máxima de preensão manual e melhora da potência muscular dos membros inferiores. As variáveis de aptidão aeróbia e anaeróbia relacionaram-se com menor queda do desempenho, maior taxa de golpes de perna e maior tempo médio de combate. Assim, observou-se predominância do sistema aeróbio para suprir a energia necessária para a realização do combate de judô. Além disso, maiores níveis de aptidão aeróbia e anaeróbia estão associados positivamente com o desempenho durante a luta / Considering that judo combat can last from a few seconds to up to more than 5 minutes, characterization of the physiological demands of combat in different time frames, and the relationship of these responses to an athlete\'s level of aerobic and anaerobic fitness is relevant to improving training methods. Thus, the objective of the present study was to describe the physiological demands of judo combat. Twelve judo athletes performed 10 experimental sessions. In the first and second sessions, four physical tests to characterize the aerobic and anaerobic fitness of the upper and lower limbs were performed. In the other sessions, the athletes performed 15 judo combat (involving 3 conditions x 5 durations of time: 1, 2, 3, 4 and 5 minutes) randomly determined, against the same opponent, on different days and blinded for time duration. In one condition, the athletes simulated actual combat. In the second condition, the athletes fought while using a gas analyzer to measure oxygen consumption in order to estimate the contribution of the energy systems. In this condition some motion adjustments were imposed. To verify if the use of the gas analyzer modified the responses obtained, in the third condition the athletes fought with the same adjustments, but did not use the equipment. These combat periods were divided into 8 sessions with two different conditions, separated by an interval of 60 minutes. The physiological, perceptual, performance, time-motion, and technical action responses were quantified in all matches. The comparison of the dependent variables was performed with an analysis of mixed models for repeated measures, followed by a post hoc Bonferroni. The associations between aerobic and anaerobic fitness to combat variables were verified using Pearson\'s correlation. For all significant pairwise comparisons the effect size (d Cohen) was calculated. A 5% level of significance was adopted for all analyses. The main results showed an increase in aerobic contribution with a concomitant reduction of the anaerobic contribution in the course of combat, given that the aerobic contribution was greater than the anaerobic contribution from the first minute of combat. The lactic anaerobic system contributed to the smaller proportion of energy cost in judo combat. The increment in rate of the physiological and perceptual responses per minute of combat decreased throughout the course of the combat, with the highest changes occurring at the beginning of combat, which suggest that judo athletes seem to modulate their effort. In the course of combat, maintenance of the average time of effort and actions occurred, but there was an increase in the average time of pause. After the combat, a decline in the dynamic strength endurance of the upper limbs was observed, while maximal isometric handgrip strength was maintained, and improvement of muscle power in the lower limbs was noted. The aerobic and anaerobic fitness variables were associated with lower fall performance, higher rate of leg attacks and a higher average time of standing combat. Thus, a predominance of the aerobic system in supplying the energy needed for the realization of judo combat was observed. In addition, higher levels of aerobic and anaerobic fitness are positively associated with performance during the combat

O conceito de cidadania tem evoluído ao longo dos anos, fonte e guardiã de direitos e deveres iguais para todos. Mas a atual educação básica, que poderia proporcionar o desenvolvimento de espírito crítico, não prepara o cidadão para decisões presentes no cotidiano. Nesse sentido, o presente trabalho se propõe a ressaltar a importância da aprendizagem sobre questões energéticas, em particular relacionadas à Eletricidade, em atenção ao desafio de conciliação de desenvolvimento humano à preservação ambiental, assim como a reunir informações e considerações que ampliem e qualifiquem a presença dessas questões na educação básica e na preparação de seus professores. Pressupostos educacionais humanistas conduzem uma análise de textos, projetos e recursos didáticos, seguida de um panorama dos problemas socioambientais, econômicos e do desenvolvimento do sistema energético brasileiro ao longo do tempo. A apresentação da atual e necessária interação interdisciplinar entre educação e preservação do meio ambiente fornece elementos para a elaboração de sugestões, no sentido de que recursos para educação básica e seus professores, especialmente do Ensino Médio, efetivamente equipem o jovem estudante em elementos para exercer sua cidadania. Levando em consideração essas preocupações, a análise dos recursos didáticos e o histórico da política energética orientam proposições e sugestões para a pretendida qualificação visando maior compreensão e participação do estudante e cidadão a respeito desse tema. / The citizenship concept evolved along the years, source and guardian of rights and duties equal for all. But the current basic school education, which could provide the social inclusion and the development of critical spirit, does not prepare the citizen for present decisions on a daily basis. On this sense, the current Paper proposes itself to emphasize the importance of the learning about energetic questions, in particular related to the Electricity, in attention to the challenge of conciliation of economic growth to the environmental preservation, as well as to collect information and considerations that broaden and qualify the presence of those questions in the basic school education and in the preparation of its professors. Presumed educational and humanists considerations lead to an analysis of texts, projects and learning resources, followed by an overview of the social-environmental issues, economical issues and of the development of the Brazilian energy system along the times. The presentation of the current and necessary interdisciplinary interaction between education and environmental preservation give elements for the elaboration of suggestions, in the sense of which resources for basic education and its professors, especially of the medium education, effectively equip the young student with elements to exercise his citizenship. Taking into consideration those concerns, the analysis of the learning resources and the historical ones of Energy Policy lead to propositions and suggestions for the desired qualification aiming a deeper understanding and a increased participation of the student and citizen about this topic.

The UK domestic sector accounts for more than a quarter of total energy use. This energy use can be reduced through more efficient building operations. The energy efficiency can be improved through better control of heating in houses, which account for a large portion of total energy consumption. The energy consumption can be lowered by using renewable energy systems, which will also help the UK government to meet its targets towards reduction in carbon emissions and generation of clean energy. Building control has gained considerable interest from researchers and much improved ways of control strategies for heating and hot water systems have been investigated. This intensified research is because heating systems represent a significant share of our primary energy consumption to meet thermal comfort and indoor air quality criteria. Advances in computing control and research in advanced control theory have made it possible to implement advanced controllers in building control applications. Heating control system is a difficult problem because of the non-linearities in the system and the wide range of operating conditions under which the system must function. A model of a two zone building was developed in this research to assess the performance of different control strategies. Two conventional (On-Off and proportional integral controllers) and one advanced control strategies (model predictive controller) were applied to a solar heating system combined with a heat pump. The building was modelled by using a lumped approach and different methods were deployed to obtain a suitable model for an air source heat pump. The control objectives were to reduce electricity costs by optimizing the operation of the heat pump, integrating the available solar energy, shifting electricity consumption to the cheaper night-time tariff and providing better thermal comfort to the occupants. Different climatic conditions were simulated to test the mentioned controllers. Both on-off and PI controllers were able to maintain the tank and room temperatures to the desired set-point temperatures however they did not make use of night-time electricity. PI controller and Model Predictive Controller (MPC) based on thermal comfort are developed in this thesis. Predicted mean vote (PMV) was used for controlling purposes and it was modelled by using room air and radiant temperatures as the varying parameters while assuming other parameters as constants. The MPC dealt well with the disturbances and occupancy patterns. Heat energy was also stored into the fabric by using lower night-time electricity tariffs. This research also investigated the issue of model mismatch and its effect on the prediction results of MPC. MPC performed well when there was no mismatch in the MPC model and simulation model but it struggled when there was a mismatch. A genetic algorithm (GA) known as a non-dominated sorting genetic algorithm (NSGA II) was used to solve two different objective functions, and the mixed objective from the application domain led to slightly superior results. Overall results showed that the MPC performed best by providing better thermal comfort, consuming less electric energy and making better use of cheap night-time electricity by load shifting and storing heat energy in the heating tank. The energy cost was reduced after using the model predictive controller.

Australia’s economy is heavily dependent on coal-based energy and greenhouse gas intensive natural resource extraction and processing industries. As part of an international climate change mitigation effort Australia will have to undergo a national transformation to a low emissions society by mid century. Federal and State Governments in Australia, like their counterparts in other major developed economies, have been persuaded that reliance on fossil fuels in stationary energy industries such as electricity generation and minerals processing will be able to continue with the deployment of a value chain of technologies fitted to these installations for capturing carbon dioxide, transporting it to a disposal site, and then injecting it into subsurface geological formations for permanent storage (carbon capture and storage, or CCS). Understanding the likely effectiveness of CCS for reducing greenhouse gas emissions from stationary energy industries is therefore critical to policy formulation for, and management of, Australia’s emissions mitigation effort and national transformation over the decades ahead. / This thesis aims to offer a clearer understanding of the practicalities, limitations and uncertainties surrounding future CCS use in Australia and of the contribution CCS can make to mitigating emissions from the Australian stationary energy sector in the period to 2050. It considers two central questions: Is CCS a realistic option for emissions mitigation in Australia? Are Australian climate policies formulated to facilitate CCS deployment and optimise its potential contribution? The criteria employed in this thesis for answering these questions are restricted to those having an ascertainable causal impact on the timing, pace and ultimate scale of CCS deployment within Australia. The methodology used for the research is grounded in critical approaches and integrated assessment within a holistic, trans-disciplinary paradigm. / This thesis finds that under Australia’s existing climate policy framework it is unrealistic to expect CCS can contribute more than 75 million tonnes of CO2 per annum to emissions mitigation by 2050. Australia does have sufficient potential geological storage resources to expect some environmentally safe CCS infrastructure could be engineered over time, but commencement of large scale build-out is not likely before 2025. When CCS will become a commercial mitigation option in Australia is unpredictable and dependent more on the political economy of climate change than on Australian research, development and demonstration activities. / The thesis also finds that the existing climate policy framework is increasing rather than decreasing the risks to timing and usefulness of CCS even to the level of 75 million tonnes of CO2 per annum by 2050. This thesis concludes that Australian Governments are not developing the institutional capability to oversee a holistic decarbonisation of the stationary energy sector. This capability is required not only to address the risks to CCS deployment but also to prevent market failures that foreclose an optimal contribution from all other potential mitigation technologies. The thesis proposes that an Australian national CCS company be created with responsibility for CCS integration, transport and storage services in order to develop Australian capability rather than that of international corporations.