Detta examensarbete är en del av energiingenjörsutbildningen i värmeteknik på Mälardalens högskola i Västerås och är en fördjupning inom ventilationsteknik. Arbetet har utförts med hjälp av företaget VentPartner i Västerås som har tillgodosett med det aktuella studerande ventilationssystemet. Syftet med detta examensarbete var att undersöka om beräkningsprogrammet MagiCAD är tillförlitligt med avseende på tryckfall i ventilationssystem samt vilken potential och påverkan programmet eventuellt kan ha för ventilationsbranschen. Tre stycken olika beräkningsmetoder för tryckfall har utförts; MagiCAD simuleringar, handberäkningar med formler och diagram samt fysiska mätningar med mätinstrument. Syftet har gått ut på att göra en jämförelse mellan dessa tre beräkningsmetoder för att med hjälp och tillsammans med tidigare forskning fastställa MagiCADs trovärdighet samt undersöka eventuella brister hos beräkningsprogrammet. Det studerade ventilationssystemet för den aktuella studien var ett till- och frånluftssystem på VentPartners kontor i Västerås. Systemet hade ett tilluftsflöde på 250 l/s och ett frånluftsflöde på 260 l/s. I arbetets tidiga skeende utfördes först ett platsbesök i syfte att ta fram referensdata av det utvalda ventilationssystemet. Med hjälp av stege, tumstock och en utskriven skiss av systemet samlade man in längd och dimensioner på kanaler, kanalernas placering i höjdled, produktinformation på don, spjäll och ljuddämpare. Därefter utfördes själva designen och uppritningen av ventilationssystemet i MagiCAD med hjälp av referensdata. När det projekterade ventilationssystemet var färdigt i MagiCAD utfördes själva tryckfallssimuleringen i beräkningsprogrammet. De manuella handberäkningarna utfördes med hjälp av formler och diagram och genomfördes i programmet Excel. De fysiska mätningarna utfördes vid ett separat platsbesök på VentPartners kontor och utfördes med universalmätaren Swema 3000 som Ventpartner tillgodosatte. Resultatet av tryckfallen ifrån MagiCAD simuleringarna och handberäkningarna skiljde sig endast en aning, både för tillufts -och frånluftssystemet. Medans tryckfallen ifrån de fysiska mätningarna skiljde sig betydligt mer jämförelsevis mot de andra två beräkningsmetoderna. Detta berodde på att MagiCAD och handberäkningarna utgår ifrån ideala förhållanden, vilket verkligheten aldrig är. Slutsatsen blev att beräkningsprogrammet MagiCAD är ett väldigt komplett och behagligt projekterings -och simuleringsprogram som är tillförlitligt. Dock har programmet sina brister i en del anpassningsfunktioner till verkligheten, men potentialen för framtiden ser ljus ut.

The aim of this thesis is to apply and evaluate potential forecasting models for solar power production, based on data from a photovoltaic facility in Sala, Sweden. The thesis evaluates single step forecasting models as well as multiple step forecasting models, where the three compared models for single step forecasting are persistence, autoregressive integrated moving average (ARIMA) and ARIMAX. ARIMAX is an ARIMA model that also takes exogenous predictors in consideration. In this thesis the evaluated exogenous predictor is wind speed. The two compared multiple step models are multiple step persistence and the Gaussian process (GP). Root mean squared error (RMSE) is used as the measurement of evaluation and thus determining the accuracy of the models. Results show that the ARIMAX models performed most accurate in every simulation of the single step models implementation, which implies that adding the exogenous predictor wind speed increases the accuracy. However, the accuracy only increased by 0.04% at most, which is determined as a minimal amount. Moreover, the results show that the GP model was 3% more accurate than the multiple step persistence; however, the GP model could be further developed by adding more training data or exogenous variables to the model.

The concern of climate change and Greenhouse Gas emission have increased national consideration toward energy efficiency. Despite noticeable action which have taken by EU cities and Sweden government to mitigate the climate change, there is still shortage in appropriate energy measurements in old residential buildings. Due to the fact that a large share of residential buildings in Sweden have constructed more than 40 years ago, most of them need energy renovation  to enhance efficiency and saving more energy. In order to encourage home owners toward energy efficiency renovations, some cost effective measurements have to introduce to people with the view of effect on property value.  To this end, 50 detached houses and villas in Kronoberg County in Sweden have been chosen and analyzed to identify how renovation can increase the property value. These houses have been set in different categories by location, heating system, deep renovation, energy and aesthetic renovation. After that, compares the sold prices and biding prices for each category. Moreover, it analyses the people behavior toward renovation to see how can motive people to adopt necessary energy efficient renovation. This research also shows the current situation of building renovation, the most favourite renovation which are adopted by people as well as providing information about the factors affect the value of the house after renovation.

An existing solar-powered water pumping system located in Mutomo, Kenya has beenevaluated in this paper. The requirement for this system is to produce a minimum of25m³ water per day throughout the year.The aim of this thesis is to investigate theperformance of the currently installed system and find a suitable replacement in termsof efficiency and economic viability. In order to acquire the necessary knowledge forthis project, a literature study was carried out to analyse the research within the area.Three simulation models were created which all include an electric motor driven by aphotovoltaic array and are connected to a submersible groundwater pump. Allmodels utilise space vector pulse width modulation. One model of an inductionmotor that represents the currently installed system, one induction motor thatdelivers a minimum of 25 m³ water per day, and one model of a permanent magnetsynchronous motor for comparison. Simulations using weather data, representing anaverage day for each month of the year were carried out. It was shown that thecurrently installed system does not fulfil the requirement of producing 25 m³ waterper day, and in addition produces a significant amount of energy that can not beutilised. It was also shown that the efficiency of the permanent magnet synchronousmotor was superior to the induction motors. In order to compare the systems interms of economic viability, price quotations from world leading manufacturers wereacquired. The results of the economic comparison show that the superior efficiencyof the permanent magnet synchronous motor was not enough to compensate for thehigher investment cost.

There is a challenge to feed an increasing world population. Simultaneously, as more people rely on food production, ensuring a sustainable food production becomes more important. In two of the United Nations’ seventeen sustainable development goals food is mentioned, and one of the more specific targets regards making public procurements more sustainable. There are however challenges with regards to how to reduce a Swedish public procurement’s environmental impacts. This is due to some fundamental principles every Swedish public procurement must follow. This thesis examines the environmental impacts of two public procurements of food, regarding global warming, acidification and eutrophication. It also examines whether calculating food’s environmental impacts per serving or per kg is the more representative approach. Lastly, this thesis examines how the environmental impacts of a public procurements of food can be reduced. Consequently, a methodology of how to minimize the environmental impacts of a procurement is presented. Firstly, the results show that the environmental impacts per servings and per kg differ. One procurement has approximately 50-60% higher environmental impacts compared to the other when measured per serving, but approximately 2-9% lower impacts when measured per kg. The authors argue that representing the environmental impacts per serving is more accurate, since it is more correlated to nutritional values. Secondly, the results show that the environmental impacts for minimizing each environmental impact category differs.

Att minska energianvändningen är lika mycket ett globalt mål som ett nationellt mål. Sverige har som mål att öka effektiviseringen av energianvändningen med 20 % fram till år 2020. Det gör att nästan alla sektorer påverkas och inte minst bostads- och servicesektorn som står för nästan 40 % av Sveriges energianvändning. Ventilationssystem är en av de saker som kan bidra till energibesparingen. I den här studien har en nybyggd grundskola simulerats avseende energi och komfort där olika ventilationssystem testats för att se vilket system som är mest lönsamt ekonomiskt, energi- och komfortmässigt. Det som skiljer ventilationssystemen åt är de olika typerna av flödesreglering. Två huvudtyper av ventilationsflödesreglering har testats: ”Variable Air Volume” = Luftflödet varierar efter behovet (VAV) och ”Constant Air Volume” = Konstant luftflöde (CAV). Byggnaden, som är välisolerad och har tung stomme, har även simulerats med ökad personbelastning för att se hur det påverkar ventilationssystemet. Metoden som används för att utföra arbetet är en simuleringsstudie av komparativt slag, där datorprogrammet IDA ICE 4.8 har använts för att modellera byggnaden och utföra simuleringarna. Modellen som har simulerats efterliknar delar av grundskolan Stigslundsskolan i Gävle, i både uppbyggnad, ventilation och användningsgrad. Data har samlats in från konsultföretaget Rambolls databaser med information om projekteringen av skolan och genom personlig kommunikation. Simuleringen av ett skolår har utförts och ett schema för personbelastningen har ställts in för varje sal för att efterlikna det schema som eleverna går efter i dagsläget. Resultatet av simuleringarna visade att VAV -ventilationssystemet som efterliknar det projekterade fallet väl täckte ventilationsbehovet, använde mindre energi än CAV-systemet och skapade ett mycket bra termiskt klimat i byggnaden. Resultatet visade också att ökad personbelastning hade stor inverkan på ventilationssystemet, och medförde bland annat att återbetalningstiden för VAV-systemet ökade från 11 till 30 år. / To reduce the energy use is as much a global goal as it is an international goal. The Swedish goal is to increase the efficiency of energy use with 20 % by year 2020. This means that almost all the sectors are affected, that includes the housing and service sector which accounts for almost 40 % of Sweden’s energy use. The ventilation system is one thing that can contribute to saving energy. In this study a new built primary school has been simulated, regarding energy use and thermal comfort, where different ventilation system has been tested to determine which system are the most profitable in economically, energy and comfortably. The ventilation system different in the flow control. Two main types of flow control have been tested: Variable Air Volume (VAV) and Constant Air Volume (CAV). The building, which is well insulated and has a heavy body has also been simulated with increased personal load to see how it affects the ventilation system. The method used to perform the work is a comparative type simulation study. The computer program IDA ICE 4.8 has been used to build the model and do the simulations. The model that has been simulated resemble the primary school Stigslundsskolan in Gävle in both construction, ventilation and degree of use. Data has been collected from the consulting company Ramboll’s database with information on the planning of the school. Personal communication has also been used to collect information. The simulations have been performed for a school year and a schedule for the personal load has been set for each hall to imitate the schedule that the students are following today. The result of the simulations showed that the VAV ventilation system, which resemble the planned case, cover the ventilation requirements, uses less energy than the CAV system and create a very good thermal climate in the building. The result also shows that the increased personal load had a great influence on the VAV ventilation system and increased the repayment period from 11 to 30 years.

In this study, the financial and economic viable of perovskite-SHJ tandem solar cells were determined using a detailed bottom-up cost model and energy-yield calculations. Attention to specific advancements in perovskite solar cell layer technology and large-scale deposition have been taken into account to create a realistic, viable commercial scale option for tandem production. A reference tandem technology is used to determine the overall manufacturing cost and minimum sustainable price. Models used show that the tandem technology has the potential to be cost competitive with existing silicon technology given the uncertainty and sensitivity of the values used in this study. It was examined further how non-STC energy yield and service life contributes to the overall economic viability of the tandem module within residential, commercial and utility scale of application. Given the reference tandem module, it is expected to be competitive at the residential level with existing silicon technology if perovskite layers' service life is greater than 20 years. In commercial and utility application, the tandem model is not economically viable due to the reductions seen in the area- and project-related installation costs for existing technology. This thesis concludes by presenting the current limitations in perovskite technology that would inhibit adaptation of this into commercial-scale production and presents alternative applications in which tandem modules would be more favourable.

In this study, it was investigated how individual households could manage security of supply during an outage by installing a local energy system that could operate independently from the electricity grid. By installing local renewable off-grid energy systems, households could guarantee an uninterrupted supply of energy even during an outage on the electricity grid, while also increasing their energy autonomy during normal circumstances. The results showed that managing an outage during summer was fairly easy. Due to high electricity production, a small energy storage was enough to manage an outage during summer. However, managing an outage during winter was more critical. During winter, the systems needed to be almost fully reliant on the energy storage. This significantly increased the cost of these systems. Due to the high cost for the energy systems today, it was not considered a feasible solution to improve energy security at a national level. However, at a local level, this was considered to have the potential to improve energy security. First, it could to be of interest for people who already have installed solar panels, who could add a battery and thereby be able to manage an outage during summer. Second, it could be of interest for people who are more exposed to outages or have a low trust in the system to work properly. Lastly, this could be of interest for actors for whom backup energy is important, for instance for the industry.

The analysis of unbalanced power system problems using the method of phase co-ordinates by which the phase quantities are preserved has obvious practical advantages over the transformation methods requiring the phase quantities to be substituted by, for example, symmetrical component and d-q quantities. Since the physical identity of the system is maintained in the phase frame of reference, the matematical models of the system can be subjected to actual operating constraints enabling a unified approach to be adopted in the study of both symmetrical and unsymmetrical conditions. In this thesis the bond graph techniques are used to model power system components in terms of their phase co-ordinates. The bond graph structure, which is based on energy continuity and power balance, classifies system and sub-systems, with respect to the number of energy ports through which energy or power is exchanged with the environment as well as in terms of the particular internal energy transformations involved. The use of bond graphs for the analysis of non-linear electromagnetic systems has resulted in the evolution of a uniform diagramatic structure which, represents in a single diagram the basic field properties such as the magneto-motive force and the flux linkages together with the conjugate circuit power variables, voltage and current. As an extension of this ideal the general n-port electromagnetic and electrostatic field systems are derived in bond graph notations. A very desirable feature of this method of presentation is that there exists a one-to-one-correspondence between the bond graph and a computation structure which may be used for the purpose of simulation by either analogue or digital computers. The general n-port electromagnetic and electrostatic field systems form the basis for the effective modelling of power system components such as rotating machines, transformers and transmission lines. In the investigations of earth faults, these models are simplified in accordance with the need of the particular study but are sufficiently accurate representations to allow predictions on the overall system behaviours. The bond graph approach is ideally suited to expedite the modelling of dynamic interacting energy systems and when used in conjunction with the computation structure can provide the simulation technique required to model accurately the non-linear behaviours of multiport electromechanical energy converters. The effects of magnetic saturation in synchronous generators are presented in detail.

O objetivo deste estudo foi investigar as contribuições dos sistemas energéticos e do gasto energético total em situação de luta. A amostra foi composta de 10 atletas do sexo masculino de nível nacional/internacional (21±6 anos; 176.2±5.3cm; 67.2±9.0kg), competindo em nível internacional. Para a estimativa das contribuições energéticas e do gasto energético total, foram realizados três protocolos simulando combate (um round, dois rounds e três rounds). As lutas foram filmadas para quantificação das ações motoras em cada round. A estimativa dos sistemas energéticos aeróbio (WAER), anaeróbio alático (WPCR) e anaeróbio lático (W[La-]) foi realizada através do consumo de oxigênio durante a atividade, do delta da concentração sanguínea de lactato de cada round e do débito alático de oxigênio (DAO2), respectivamente. A razão entre as ações de elevada intensidade e momentos de baixa intensidade (step e pausa) no protocolo 3 foi ~1:7. Os resultados dos sistemas WAER, WPCR e W[La-] no protocolo 3 foi 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectivamente. Assim, as sessões de treinamento devem ser direcionadas principalmente para a melhoria do sistema anaeróbio alático (responsável pelas ações de alta intensidade), e do sistema aeróbio (responsável pelo processo de recuperação entre as ações de alta intensidade) / The purpose of this study was to investigate energy system contributions and energy cost in combat situation. The sample was constituted by 10 male taekwondo athletes at national/international level (age: 21±6 years old; height: 176.2±5.3cm; body mass: 67.2±9.0kg) competing at national/international level. To estimate the energy contributions and total energy cost of the fights, athletes performed a three different protocols simulated competition (1 round, 2 rounds and 3 rounds). The combats were filmed in order to quantify the actual time spent fighting in each round. The estimate of the aerobic (WAER), anaerobic alactic (WPCR) and anaerobic lactic (W[La-]) energy systems was carried out through the oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the delta of blood lactate concentration in each round, respectively. The mean data between the high intensity actions and moments of low intensity (step and pause) was ~1:7. The results of WAER, WPCR and W[La-] system contributions were 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity)