This thesis discusses topics in the field of process engineering that have received much attention over the past twenty years, process integration and optimization of energy and environmental systems. It emphasizes the applications of three commercial software tools for process integration, ADVENT, HEXTRAN and SlTPERTARGET, that are readily available to academic users at low costs. Specifically, Chapter 1 presents an overview of the basic concepts used in process integration of energy systems. Chapter 2 compares the use of single and dual temperature-of-approach methods to synthesize energy-optimum and minimum-cost, heat-exchanger networks (HENs), and shows how to implement them using three software tools. Chapters 3 and 4 demonstrate how to optimize the energy recovery in petroleum refinery distillation systems via process integration. Chapter 3 presents an extension to a case study of heat integration of a vacuum distillation system. Chapter 4 describes the detailed synthesis, retrofit and optimization of HENs for a system of atmospheric and vacuum distillation towers, and it represents the first process integration and optimization study of a complex process in petroleum refineries using all three commercial software tools. Chapter 5 presents, through four progressive tutorial examples, a recent conceptual method developed in the field of process integration of environmental systems applied to wastewater minimization and to the design of distributed effluent treatment systems. / Master of Science

Biogas is produced during anaerobic degradation of organic material and mainly consist of methane and carbon dioxide. During the anaerobic degradation, the products are fatty acids such as propionate, butyrate and acetate. In the biogas process a syntrophic cooperation between different microorganisms are important, this involves syntrophic acetate oxidizing bacteria (SAOB) which degrade acetate, syntrophic propionate oxidizing bacteria (SPOB) which degrade propionate and methanogens which produces methane. The propionate degradation is often the slowest step in the biogas process since the microorganism involved do not get much energy from it. It has been observed that FeSO4 and FeCl2 improved the propionate degradation rate in thermophilic SPOB enrichment cultures but no impact on mesophilic enrichment cultures was observed.  The aim of this study was to determine the impact by Fe/S-addition on the key species (SAOB, SPOB and methanogens) involved in the propionate degradation in mesophilic enrichment cultures and cultures with sludge with high ammonia concentration. Furthermore, cultivation studies are performed to reveal the optimal concentrations of iron (FeCl2), which boost the propionate degradation rate in mesophilic SPOB-cultures.  The cultivation study was performed in batches (<500 mL) with 50 mM propionate, 0.3 mM ammonium and different FeCl2 concentrations between 0 to 20 mM. To determine the optimal FeCl2 concentration, the cultures were analysed by measuring the propionate, methane and acetate concentration using High Performance Liquid Chromatography (HPLC). The mesophilic enrichment cultures were treated with FeSO4, FeCl2, NaSO4, FeS, FeCl3, Fe2(SO4)3 and Na2S. The mesophilic cultures with sludge were treated with FeSO4, FeCl2, FeCl3, and a combination of all three compounds. The impact of Fe/S compounds on SAOB, SPOB and methanogens were analysed on the mesophilic enrichment cultures and cultures with sludge by measuring the copies of 16S rRNA gene using quantitative PCR (qPCR). It could be concluded that in the mesophilic enrichment culture none of the Fe/S compounds affected the SPOB or methanogens, but FeS increased the concentration of SAOB. In the mesophilic culture with sludge, FeCl2 and FeCl3 increased the SPOB level, however, FeSO4 decreased the SPOB level. Moreover, the SAOB levels decreased for FeCl3 and when all three compounds were combined. The methanogen level decreased over time by the compounds FeCl2 and FeSO4. From the cultivation study, the optimal FeCl2 concentration was 20 mM.

This thesis aims to compare the performance of building integrated PV to “market leading” building applied PV and determine which technology is the most profitable. A case study is conducted of the real estate company Vasakronan’s two buildings Magasin X and Celsius which have both building-integrated PV in the facade and building-applied PV on the roof. The power output from the building-integrated PV systems compared to the building-applied PV systems is studied for each of the four seasons of the year. The system design including technical specifications for the modules and inverters as well as relevant weather data for Uppsala was implemented in the simulation software SAM. By simulating the PV systems in SAM an expected power profile is generated which in comparison with the actual power output from the PV systems could indicate if they are performing optimally. A Life Cycle costing (LCC) analysis is performed to give an understanding of the economic profitability of the different technologies over time. To include the perspective of the challenges in expanding the market for building integrated PV in Sweden, two interviews are conducted.  The results show that the BIPV generates more energy than the BAPV per square meter during the winter. During the spring and autumn, the weather conditions have a great impact on the perfor- mance of the solar modules. During sunny days of spring the temperature of the modules increase which decrease their efficiency and hence the generated power. The results also indicate that the actual power output from both the BIPV and the BAPV overall are performing as expected from the theoretically generated power in SAM. There are cases where the facade-integrated photovoltaics exceed its theoretical power output values. In contrast, roof-applied photovoltaics exhibit a closer correlation with theoretical values, although with a tendency to underperform overall.The life cycle cost analysis indicates that for both buildings, Magasin X and Celsius, only the BAPV system is profitable. In contrast, the BIPV installation is not cost-effective without subsidies. However, as shown in the sensitivity analysis, the electricity price is a factor which has a large impact on the profitability of the system. With a doubled electricity price the entire solar cell installation of Mag- asin X has a pay-back time of 10.6 years and is considered profitable. It can also be concluded that there is a lack of knowledge of how to implement BIPV in the most efficient way as well as what amount of energy the BIPV systems are expected to generate. To expand the BIPV market, stakeholders need to share their knowledge and a standardized process will need to be developed for choosing BIPV for new buildings. Subventions can motivate companies to implement BIPV in practice which is crucial for the spreading of such knowledge and the future development of BIPV.

As Europe confronts a substantial surge in energy demand, the pressing necessity to integrate nuclear energy and others low-carbon energy sources into the energy mix has become evident. This integration is of paramount importance to achieving the objective of zero emissions by 2050, as outlined in various European Union climate policies. The role of nuclear energy, particularly through the deployment of Small Modular Reactors and Generation IV reactors, is pivotal in ensuring a dependable and sustainable energy supply that meets rigorous environmental standards.The public perception of nuclear energy plays a critical role in its acceptance and implementation. This thesis examines the importance of societal views on nuclear power, addressing common concerns and misconceptions through transparent communication and education. Engaging the public in discussions about the advancements in nuclear technology, especially the enhanced safety features and reduced environmental impact of modern reactors, is essential for gaining widespread support. Furthermore, the development of Generation IV reactors is imperative for addressing the challenge of nuclear waste management. These advanced reactors are designed to be more efficient and generate less waste, with some concepts capable of recycling spent fuel and using it as a resource. By focusing on these technologies, it is possible to mitigate the long-term environmental impact of nuclear energy and enhance its sustainability.This research is a purely literature review that highlights the necessity of advancing nuclear technology and fostering public trust to successfully integrate nuclear energy into Europe’s future energy strategy. The achievement of a zero-emissions energy mix by 2050 will necessitate a multifaceted approach that combines technological innovation, robust regulatory frameworks, and proactive public engagement. The findings of this thesis underscore the potential of SMRs and Generation IV reactors to transform the nuclear energy landscape, making them a cornerstone of a clean and reliable energy future.

This thesis investigates the application of two different modeling techniques for simulating nuclear fuel rods: Constructive Solid Geometry (CSG) with Boolean operations in Serpent and mesh-based modeling in OpenFOAM. The purpose of the study was to evaluate how a mesh-based model performs compared to a CSG-based model when conducting simulations on a relatively simple geometric configuration. The reasons for using mesh-based geometry include the ability to couple Serpent with OpenFOAM, enabling simulations in both codes using the same geometry, and accommodating users who might be more comfortable with mesh-based software. By performing a direct comparison between the results from the two modeling methods, the project aimed to assess the accuracy, efficiency, and practical usability of mesh-based geometry in nuclear simulations. The results indicate that mesh-based modeling, particularly with finer mesh, can achieve a level of detail and accuracy comparable to that of CSG models. However, the simulations with finer mesh took significantly longer to complete, highlighting the need for careful consideration of mesh size depending on the specific requirements of the simulation. The study encompasses several critical aspects, including computational speed and the precision of the resulting simulation data. The analysis demonstrates that while mesh-based modeling offers high precision and flexibility, it is more computationally intensive. In contrast, CSG is faster and simpler to implement for less complex geometries, but may not adequately capture more intricate details. The conclusions suggest that mesh-based modeling can be a viable alternative for complex simulations, provided that the computational resources are available. By highlighting the potential and limitations of mesh-based modeling in comparison to traditional CSG techniques, the study provides valuable insights. Utilizing mesh-based models is highly advantageous when CFD simulations are planned, as it avoids the need to simulate one model in Serpent and another in CFD. Thus, mesh-based geometry is a promising toolkit for achieving high precision and efficiency in detailed and intricate simulations within the nuclear field.

This project investigated the feasibility of installing photovoltaic systems with electrical heating on underdimensioned roofs in arctic climate, with the purpose of reducing the snow load. The northern part of Sweden is undergoing an industrial transition and more renewable electricityneeds to be produced. Solar panels on roofs can offer short processes from planning to production of renewable energy, reduced load on the electricity grid and more energy-efficient buildings, without interfering with other interests. Experimental tests were conducted on a snow-covered solar panel mounted on load cells while electric heating was supplied. The snow load was measured during the test, which was conducted twice. During the first test the temperature of the air was −3℃ and an average load reduction of 17N/(m2,h) was observed. The second test was performed at an air temperature of −11℃, and an average load reduction of 9N/(m2,h) was observed. The efficiencies were 40% for the first, and 22% for the second test. The project also included a case study on a building that was underdimensioned for the snow load and thus in need of manual snow removal. It was considered whether a PV system with electric heating for snow removal would be a valid option technically and economically. Two PV-systems were designed in the case study. One system was designed to make manual snow removal accessible, and the other system was equipped with electric heating to reduce snow load. Based on the experimental tests it was concluded that snow load reduction could be performed quick enough, making the technology feasible if precipitation can be predicted in advance. The system designed for manual snow removal resulted in an energy production of 174.5MWh with 𝑃tot=244.8kW, 𝑁𝑃𝑉=333 000SEK and 𝐼𝑅𝑅=7.8%. The system with electric heating resulted in an energy production of 266.6MWh with 𝑃tot=374kWp. The reason why the system with electrical heating generates more energy is because the whole roof area was covered with solar panels. Same percentage of losses due to snow shadowing was assumed for the two systems. The economic analysis was conducted for snow removal at average temperature during February, Mars and April in Storuman (−4℃). The system performed 𝑁𝑃𝑉=−148 000kr and 𝐼𝑅𝑅 = 5.6%. The concluding recommendation for the case study is to install a conventional PV-system because of its economic performance and safety.

This thesis investigates the integration of artificial intelligence (AI) into the Swedish electricity sector, focusing on enhancing operational efficiency and business value creation. With forecasts predicting a doubling of Sweden's electricity consumption by 2045 and the recent surge in AI applications, this research explores whether AI can help mitigate challenges arising from increased electricity consumption. Sweden's transition to weather-dependent renewable energy sources places higher demands on the functionality of its electrical grid, established in the early 20th century, which now requires significant upgrades. Using the Technology-Organizational-Environmental (TOE) framework, the study examines key aspects of AI integration. A qualitative methodology, employing Grounded Theory, gathers insights through iterative interviews with key actors in the AI and Swedish electricity sectors. Findings indicate that AI has the potential to optimize energy management, improve grid stability, and support the transition to renewable energy sources within the Swedish electricity sector. However, challenges such as cybersecurity, data management, and regulatory compliance are significant. The study concludes with strategic recommendations for AI integration, emphasizing the importance of robust data infrastructure, skilled personnel, and adaptive regulatory frameworks to integrate AI into the Swedish electricity sector and create business value. Moreover, transparency and education are highlighted as crucial for building public trust and ensuring that AI enhances human capabilities. / <p>Tomas var examinator för Teknisk Fysik där Alexander var teknisk ämnesgranskare. Carla var examinator för Energisystem där Rafael var teknisk ämnesgranskare. Arbetet skrevs med Entreprenörsskolan på Uppsala Universitet där Matthew var ämnesgranskare.</p>

Urban microgrids are smart and complex energy systems that help integrate renewables into our cities, turning our neighborhoods into partly energy self-sufficient hubs. Moreover, they create the space for electricity transactions between neighbors, transforming the former consumers into prosumers. The following work proposes the implementation of an urban microgrid to a neighborhood in Lisbon, Portugal. This dissertation’s objective is designing and discovering the optimal photovoltaic and storage capacity, optimal electricity dispatch, effects of distributed energy production in grid voltage and economic viability of such a system. With this purpose, a comprehensive model was elaborated, considering specific site weather data, electric loads, grid topology and utility tariffs. The self-sufficiency of Arco do Cego was found to be 66% in this study, reducing its carbon footprint by 61%. A detailed map of where to place each PV system and battery bank was generated, with specific electricity dispatch strategies. Moreover, the system was designed under real grid voltage, current and power flow constraints.

Backup diesel generator (DG) systems continue to be a heavily polluting and costly solution for institutions with unreliable grid connections. These systems slow economic growth and accelerate climate change. Photovoltaic (PV), energy storage (ES), grid connected, DG – Hybrid Energy Systems (HESs) or, PV-HESs, can alleviate overwhelming costs and harmful emissions incurred from traditional back-up DG systems and improve the reliability of power supply. However, from project conception to end of lifetime, PV-HESs face significant barriers of uncertainty and variable operating conditions. The fit-and-forget solution previously applied to backup DG systems should not be adopted for PV-HESs. To maximize cost and emission reductions, PV-HESs must be adapted to their boundary conditions for example, irradiance, temperature, and demand. These conditions can be defined and monitored using measurement equipment. From this, an opportunity for performance optimization can be established. The method demonstrated in this study is a techno-economic and environmental approach to improving the performance of PV-HESs. The method has been applied to a case study of an existing PV-HES in Kenya. A combination of both analytical and numerical analyses has been conducted. The analytical analysis has been carried out in Microsoft Excel with the intent of being easily repeatable and practical in a business environment. Simulation analysis has been conducted in improved Hybrid Optimization by Genetic Algorithms (iHOGA), which is a commercially available software for simulating HESs. Using six months of measurement data, the method presented identifies performance inefficiencies and explores corrective interventions. The proposed interventions are evaluated, by simulation analyses, using a set of techno-economic and environment key performance indicators, namely: Net Present Cost (NPC), generator runtime, fuel consumption, total system emissions, and renewable fraction. Five corrective interventions are proposed, and predictions indicate that if these are implemented fuel consumption can be reduced by 70 % and battery lifetime can be extended by 28 %, net present cost can be reduced by 30 % and emissions fall by 42 %. This method has only been applied to a single PV-HES; however, the impact this method could have on sub-Saharan Africa as well as similar regions with unreliable grid connections is found to be significant. In the future, in sub-Saharan Africa alone, over $500 million dollars (USD) and 1.7 billion kgCO2 emissions could be saved annually if only 25 % of the fuel savings identified in this study were realized. The method proposed here could be improved with additional measurement data and refined simulation models. Furthermore, this method could potentially be fully automated, which could allow it to be implemented more frequently and at lower cost.

“We emphasize the need to address the challenge of access to sustainable modern energy services for all, in particular for the poor, who are unable to afford these services even when they are available.”  Section 126: The Future We Want (Out Come Document of Rio+20-United Nations Conference on Sustainable Development June 20-22, 2012). The lack of energy access has been identified as a hurdle in achieving the United Nations’ Millennium Development Goals, leading towards the urge to set a goal for universal electrification till 2030. With around 600 million people in Africa without access to electricity, effective and efficient electrification programs and policy framework is required to achieve this goal sustainably. South Africa is an example in the continent for initiating intense electrification programs and policies like “Free Basic Electricity”, increasing its electrification rate from 30% in 1993 to 75% in 2010 and a claimed 82% in 2011. The case of South Africa has been analysed from the perspective of universal electrification in the coming years. The aim was to estimate the un-electrified households for each area of South Africa in order to provide the basis for electrification planning. The idea was to use available electrification statistics with GIS (Geographic Information System) maps for grid lines and identifying the suitability of on-grid or off-grid electrification options, which may help in planning the electrification of these areas in the near future. However, due to lack of readily available data, the present work has been able to estimate the un-electrified households &amp; their possible electrical load. The estimates have been distributed in different income groups for each province and district municipality of South Africa, which can be used for electrification planning at national, provincial and municipal level.  As a result, some simple and useful data parameters have been identified and an estimation methodology has been developed, which may be employed to obtain similar estimates at lower administrative levels i.e. local municipalities and wards. The work can be utilized further and feasible electrification options may be suggested for different areas of South Africa, with the help of GIS maps and data. Depending on the availability of useful data, the data parameters &amp; indicators used in this work will be helpful for planning the electrification for rural households in other places of Africa.