With the increased energy usage and its affect on the environment the European Union (EU) has issued climate and environment goals which will oversee countries energy saving potential. These goals focus on several areas including the energy usage within buildings. The purpose of this thesis is to categorize and analyze the energy saving potential for buildings constructed 1945 or earlier. The building stock in focus consists of 73 apartment buildings in Vasastaden, Linköping. The buildings were all chosen with Boverket’s database within building characteristics GRIPEN. The method consisted of stocktaking via location visits, categorizing and performing simulations on the buildings. The fictive buildings were based on the categorized building stock. They were modelled and simulated with the help of IDA Indoor Climate and Energy (IDA ICE). With the results of the energy usage a greater understanding of energy saving potential was obtained. The result of the categorization displayed that typical buildings in Vasastaden are buildings out of brick, fully detached (no adjoining walls), specifically with 3 floors. The fictive buildings have an calculated energy usage of 102-144 kWh/m2,year and have an energy saving potential within ranges of 17-41% compared to the building regulations set by Boverket (BBR). The building stock obtained an calculated energy usage of 804-3 515 MWh/m2,year. GRIPEN displayed several inaccuracies compared with the collected data from the location visits which proves that more frequent updates in databases such as GRIPEN are of high significance.

Idag står bostads- och servicesektorn för närmare 40 % av Sveriges totala slutliga energianvändning. Flerbostadshus utgör ca 30 % av den energianvändningen. Därför är det viktigt att lokalisera energiparametrar och redovisa dess betydelse för energianvändningen. Samtidigt bör relationen mellan energianvändning och inomhusklimat analyseras, så att inte förändringar i energin medför till försämringar för inomhusklimatet. Baserat på identifiering hos energisparpotentialen hos parametrar, parameterbeteende och parameterkänslighet för energianvändning har i studien ett antal parametrar undersökts för ett flerbostadshus. Även parametrarnas betydelse för det termiska klimatet har utifrån de parametrar som visat sig ha störst energisparpotential studerats. Studien är tänkt att komma till nytta för presentation av energisparpotentialer och beaktande hos indataparametrar vid energiberäkningar, samt öka förståelsen för hur termiska komforten påverkas av olika parametrar. En referensbyggnad har modellerats i programmet IDA ICE 4.5 och typisk spridningen för olika parametrar för byggnader från år 1970 till nutid har varierats och jämförts med ett referensfall. För det termiska klimatet har kriterier enligt certifieringsprogrammet Miljöbyggnad utnyttjats. Resultatet visar att ventilationssystem har stor energisparpotential. Vid en övergång från F-system till FTX-system görs betydande energibesparing, samtidigt som det sker en förbättring av den termiska komforten. Inomhustemperaturen har visats sig vara den känsligaste parametern vid beräkning av energianvändning. För den termiska komforten är fönsters g-värde och inomhustemperatur viktiga parametrar att beakta. Resultatet av energi- och komfortsimuleringarna visar också på en tydlig korrelation mellan energianvändning och termisk komfort. / Building stock consumes 40 % of total energy usage in Sweden, dwellings contribute almost 30% of the proportion. With an interest on the parametric analysis and its corresponding energy saving potentials, the investigation on the sensitivity of selected building parameters in a typical Swedish slab house is performed in the study. Based on the identification to the behavior of target sensitive parameters, the upgrading potential of thermal comforts is comparably analyzed with respect to approach the optimization design of further retrofitting scenario and uncertainty guidelines. A slab house built after 1970 is selected as the represented case building with a detailed typology introduction. In the study, IDA ICE 4.5 is applied to perform both the energy simulation and thermal comfort estimation. Based on the local screening analysis and the setting of criterion system, the ranking of the target parameters is rated systematically. The study is meant to be useful for the presentation of energy saving potentials and consideration of input parameters on energy calculations, and increase understanding of how thermal comfort is affected by various parameters. The results show that accomplished with the transformation of F-system to FTX-system, the applicable ventilation system efficiency shows the largest energy saving potential and improved thermal comfort, and the indoor temperature shows the largest sensitivity to the total energy profile. Comparably, along with the indoor temperature, the performance of glazing system in terms of the g-value is recognized as the parameters with the highest consideration. Based on the sensitivity analysis, the correlation between the energy savings and thermal comfort upgrading is verified, which indicate the possibility of providing optimal design scenario for both architectural error guidelines and further building retrofitting.

I Sverige är fjärrvärme den vanligaste uppvärmningsformen. Vatten värms upp i en fjärrvärmeanläggning och distribueras genom nedgrävda rör i marken, också kallat fjärrvärmenätet. En tillförlitlig energimodell anses vara ett bra och viktigt hjälpmedel för analyser av värmeförluster som uppstår i ett fjärrvärmenät vid distribueringen av det heta vattnet. Sandviken Energis styrning av framledningstemperaturen sker idag utifrån en inställd styrkurva som tar hänsyn till vad det är för utetemperatur. Det var av intresse för studien att jämföra denna styrning med en simulerad framledningstemperatur och identifiera övertemperaturer i Sandviken Energis fjärrvärmenät i Sandviken. Detta gjordes utifrån att undersöka hur olika faktorer påverkade värmebehovet. De påverkande faktorer som studerats i detta examensarbete var följande: utetemperatur, månad, tid på dygnet och vindhastighet. Mätdata gällande valda påverkande faktorer hämtades för perioderna 2015 till och med 2019, analyserades och indelades för att se deras påverkan på värmelasten. Utifrån indelningen av faktorerna utvanns ekvationer från deras effektkurvors trendlinjer. Ekvationerna användes för att skapa en simuleringsmatris för styrningen. En egenskapad masterekvation simulerade den ideala styrningen utifrån simuleringsmatrisen och de krav på påverkande faktorer som ställs av ett exempel-år. Den ideala styrningen beräknades om till en ideal framledningstemperatur och jämfördes därefter med den verkliga framledningstemperaturen. Tillsammans med en värmeförlustsimulering i NetSim, som resulterade i vad sparad energi per grad är värd, kunde besparingspotentialen beräknas. Resultatet visar på att en besparingspotential på 261 MWh är möjlig att uppnå vid en sänkning av framledningstemperaturen för att utesluta övertemperaturer i fjärrvärmenätet, vilket är en minskning med ca 1,8 % jämfört med det verkliga året. Detta skulle motsvara en besparing på ca 70 000 SEK genom en förändring av styrningen. En minskad framledningstemperatur kommer påverka resten av systemet positivt, bland annat för att returtemperaturen kommer minska, rökgaskondenseringens och pannornas effektivitet öka samt minskade utsläpp i form av bland annat CO2, för att nämna några exempel. / In Sweden district heating is the most common form of heating. Water is heated in a district heating plant and distributed through buried pipelines in the ground, also called the district heating network. A reliable energy model is considered to be a good and important tool for analysis of heat losses that occur in a district heating network when the hot water is distributed. Sandviken Energi’s control of the supply temperature is based today on a set control curve that takes into account what the outdoor temperature is. It was of interest to this study to compare this control with a simulated supply temperature and identify overtemperatures in Sandviken Energi’s district heating network in Sandviken. This was done on the basis of examining how different factors affected the heat demand. The influencing factors studied in the thesis were the following: outdoor temperature, month, time of day and wind speed. Measurement data on selected influencing factors were collected for the periods 2015 through 2019, analyzed and subdivided to see their effect on the heat load. From the subdivision of the factors, equations were extracted from the trend lines of their effect curves. The equations were used to create a simulations matrix for the control. A custom master equation simulated the ideal control based on the simulation matrix and the demands on influencing factors set by an example year. The ideal control was recalculated to an ideal supply temperature and then compared with the actual supply temperature. Together with a heat loss simulation in NetSim, which resulted in what energy saved per degree is worth, the savings potential could be calculated. The result shows that a saving potential of 261 MWh is possible to achieve by lowering the supply temperature to exclude excess temperatures in the district heating network, which is a decrease of about 1.8 % compared to the real year. This would correspond to a savings of about 70 000 SEK through a change in control. A reduced supply temperature will have a positive impact on the rest of the system, including reducing the return temperature, increasing the efficiency of flue gas condensation and boilers, and reducing emissions such as CO2, to name a few examples.

Stricter requirements from the European Union and the German government regarding the utilization of renewable and sustainable fuels for transportation, power, and heat production are currently in effect. This has led to that heavy transportation companies are looking for a more sustainable alternative to liquefied natural gas, such as liquefied biomethane. The monetary costs for the release of greenhouse gas are also increasing due to the carbon certificates that are being traded are decreasing in numbers each year. Carbon certificates grant companies an allowance of releasing a certain amount of emissions without being fined. Carbon dioxide and biomethane liquefaction can be a good investment for producers of biomethane to find new markets by for example trading in carbon certificates, selling liquid carbon dioxide, and producing liquefied biomethane as an alternative transportation fuel. The sale price of biomethane is heavily dependant on the emission factor for the biomethane and as such, capturing the carbon dioxide from the biomethane plant and off-setting fossil carbon dioxide would increase the sale price of the biomethane. The methods used are theoretical and quantitative, Numerical data was collected to be able to perform the economical and environmental calculations. The investment cost for the liquefaction technologies was scaled down to correspond to a plant with a production capacity of 350 Nm3/h. Also included in this thesis is a review of biomethane production, together with theory for the economical and environmental calculations.  By performing a technical, economical and environmental assessment of the technologies for the liquefaction of carbon dioxide and biomethane. This thesis shows that liquefaction of biomethane is not an economical viable option at the moment for plants equal or below this production capacity, due to a negative net present value, negative return on investment, sensitivity to fluctuating costs, and a high payback time. However, it could help in achieving the sustainability goals set forth by the European Union and the German government. With regards to the liquefaction of carbon dioxide it is deemed a viable investment option with an investment cost of approximately 1 million Euro and a payback time of approximately 3 years. Liquefaction of carbon dioxide could bring an extra income to the biomethane plant. This due to an added revenue in the sales of liquid carbon dioxide and an increase in the sale price of biomethane due to a reduction of the emission factor from 17 gCO2-eq /MJ to -23 gCO2-eq /MJ. The investment could also help achieving the sustainability goals by decreasing the dependence on fossil carbon dioxide for various sectors.

O presente trabalho objetiva, a partir de dados coletados dos motores elétricos em regime de trabalho, dar sua contribuição ao estudo de conservação de energia elétrica numa planta industrial. Apresenta-se o motor elétrico trifásico de indução e as diversas questões relativas ao seu uso industrial, para então, demonstrarem os parâmetros elétricos obtidos. Elaborou-se um trabalho de campo, que possibilita à análise da eficiência energética no uso de motores elétricos em uma fábrica de papel e cosméticos. A partir de medidas dos parâmetros elétricos como: corrente e tensão, mais os dados de catálogos do fabricante, chegaram-se aos valores de rendimento, fator de potência e fator de utilização, para diversas condições de carga dos motores. Caso o fator de utilização seja inferior a 75%, um estudo comparativo permitirá as decisões de substituição dos motores super dimensionados. Os dados são usados para as seguintes análises: qual a possível conservação de energia elétrica para cada setor, se os motores fossem substituídos por unidades de alto rendimento?; qual a viabilidade de cada setor realizar as trocas imediatas por motores de alto rendimento?; qual à economia de energia elétrica por setores em (R$/dia), utilizando motores de alto rendimento?; em quanto tempo obteríamos o retorno desse investimento? Alguns recursos de informática foram utilizados nos cálculos realizados. Os resultados indicam que o potencial de conservação de energia elétrica em motores deve ser melhor explorado e de forma mais consciente. / The objective of the present research, from a data set of electric motor collected in a regimen of work, give its contribution to the study on industrial electrical motors’ energy saving. It present the three-phase induction motor, the various issues of its industrial use and the electric parameter set collected are then presented. Field of work was elaborated, wich allowed the analysis of the energy efficiency in the use of electric engines in industry of paper and cosmetics. Given the measurements of current and tension, plus the data from the manufacter’s catalogs, values of efficiency were obtained, power factor and utilization factor, for diverse conditions of engine load. But in case the utilization factor is less than 75%, a comparative study allowed the decisions of substitution of the poorly dimensioned engines. The data are analyzed in ways: 1)What would be the energy save to each sector, if motors were changed for high efficient units? 2)What would be the viable to each sector to replace immediately the existing motors for high efficient? 3)What would be the energy save to each sector in (R$/day), using high efficient motors? 4)How much time would be the return of the investiment?. Some resources of computer technology were used in the calculations. The results showing the electric energy saving potential in motor would be better use to advantage and more conscientions form.

O presente trabalho objetiva, a partir de dados coletados dos motores elétricos em regime de trabalho, dar sua contribuição ao estudo de conservação de energia elétrica numa planta industrial. Apresenta-se o motor elétrico trifásico de indução e as diversas questões relativas ao seu uso industrial, para então, demonstrarem os parâmetros elétricos obtidos. Elaborou-se um trabalho de campo, que possibilita à análise da eficiência energética no uso de motores elétricos em uma fábrica de papel e cosméticos. A partir de medidas dos parâmetros elétricos como: corrente e tensão, mais os dados de catálogos do fabricante, chegaram-se aos valores de rendimento, fator de potência e fator de utilização, para diversas condições de carga dos motores. Caso o fator de utilização seja inferior a 75%, um estudo comparativo permitirá as decisões de substituição dos motores super dimensionados. Os dados são usados para as seguintes análises: qual a possível conservação de energia elétrica para cada setor, se os motores fossem substituídos por unidades de alto rendimento?; qual a viabilidade de cada setor realizar as trocas imediatas por motores de alto rendimento?; qual à economia de energia elétrica por setores em (R$/dia), utilizando motores de alto rendimento?; em quanto tempo obteríamos o retorno desse investimento? Alguns recursos de informática foram utilizados nos cálculos realizados. Os resultados indicam que o potencial de conservação de energia elétrica em motores deve ser melhor explorado e de forma mais consciente. / The objective of the present research, from a data set of electric motor collected in a regimen of work, give its contribution to the study on industrial electrical motors’ energy saving. It present the three-phase induction motor, the various issues of its industrial use and the electric parameter set collected are then presented. Field of work was elaborated, wich allowed the analysis of the energy efficiency in the use of electric engines in industry of paper and cosmetics. Given the measurements of current and tension, plus the data from the manufacter’s catalogs, values of efficiency were obtained, power factor and utilization factor, for diverse conditions of engine load. But in case the utilization factor is less than 75%, a comparative study allowed the decisions of substitution of the poorly dimensioned engines. The data are analyzed in ways: 1)What would be the energy save to each sector, if motors were changed for high efficient units? 2)What would be the viable to each sector to replace immediately the existing motors for high efficient? 3)What would be the energy save to each sector in (R$/day), using high efficient motors? 4)How much time would be the return of the investiment?. Some resources of computer technology were used in the calculations. The results showing the electric energy saving potential in motor would be better use to advantage and more conscientions form.

<p dir="ltr">Smart windows, dynamically adjusting optical transmittance, face global adoption challenges due to climatic and economic variability. Aiming these issues, we synthesized a methyl cellulose (MC) salt system with high tunability for intrinsic optical transmittance (89.3%), which can be applied globally to various locations. Specifically, the MC window has superior heat shielding potential below transition temperatures while turning opaque at temperatures above the Lower Critical Solution Temperature (LCST), reducing the solar heat gain by 55%. Such optical tunability is attributable to the particle size change triggered by the temperature-induced reversible coil-to-globular transition. This leads to effective refractive index and scattering modulation, making them prospective solutions for light management systems, an application ahead of intelligent fenestration systems. MC-based windows demonstrated a 9°C temperature decrease compared to double-pane windows on sunny days and a 5°C increase during winters in field tests, while simulations predict an 11% energy savings.</p><p dir="ltr">Incorporating MC-based phase change materials in passive solar panels indicated optimized energy efficiency, offering a sustainable alternative. Real-time simulations validate practical applicability in large-scale solar panels. Furthermore, a temperature-responsive sorbent with a dark layer demonstrates an optimal optical and water uptake performance. Transitioning between radiative cooling and solar heating, the sorbent exhibits high water harvesting efficiency in lab and field tests. With an adjustable LCST at 38 ℃, the cellulose-based sorbent presents a potential solution for atmospheric water harvesting, combining optical switching and temperature responsiveness for sustainable water access. Furthermore, the ubiquitous availability of materials, low cost, and ease-of-manufacturing will provide technological equity and foster our ambition towards net-zero buildings and sustainable future.</p>

This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region. The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device. Numerical predictions using three turbulence models (renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ω model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ω model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range. The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study. This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.

Predložená doktorandská dizertačná práca (ďalej len práca) sa zaoberá rozsiahlou analýzou valčekového hydrogenerátora s premenlivým geometrickým objemom a predikciou výkonových úspor dosiahnutých aplikáciou navrhnutého valčekového hydrogenerátora s premenlivým geometrickým objemom v hydrostatickom pohone vybraných mobilných pracovných strojov. Teoretický rozbor princípov fungovania valčekového hydrogenerátora a teória jednorozmerného simulačného modelu sú popísané v prvej časti práce. Na základe odvodenej teórie je vytvorený simulačný model, ktorý je vhodný na predikciu priebehu tlaku v komorách valčekového hydrogenerátora, síl pôsobiacich na valček a na predikciu vnútorných únikov vzniknutých skratovaním rozvodovej dosky, ktoré majú priamy vplyv na objemovú účinnosť valčekového hydrogenerátora. Simulačný model bol úspešne použitý pre optimalizáciu rozvodových dosiek valčekového hydrogenerátora a vhodnosť simulačného modelu potvrdili následné merania Práca obsahuje aj analýzu síl pôsobiacich na vodiaci prstenec, ktorej výsledky boli taktiež potvrdené meraním. Analýza týchto síl môže vylepšiť v konečnom dôsledku parametre budúcich tlakových regulácii. Práca ďalej obsahuje základné porovnanie použitých tlakových regulácii. Všetky uskutočnené merania potvrdili, že valčekový hydrogenerátor s premenlivým geometrickým objemom s testovanými tlakovými reguláciami je schopný úspešne pracovať v hydrostatickej prevodovke. Druhá časť práce analyzuje potenciál výkonových úspor valčekového hydrogenerátora s premenlivým geometrickým objemom pre dve mobilné aplikácie - teleskopický nakladač s hmotnosťou 9 ton a kombajn s hmotnosťou 20 ton. Analýza vyžaduje jednorozmerný simulačný model hydrostatického pohonu s teplotnou predikciou hydrostatickej prevodovky. Dva rozdielne koncepty variabilného doplňovacieho systému hydrostatickej prevodovky sú porovnané so štandardným doplňovacím systémom pre pracovný a transportný režim oboch vybraných typov vozidiel. Simulácia pohonu vozidla s valčekovým hydrogenerátorom s premenlivým geometrickým objemom vo funkcii doplňovacieho hydrogenerátora a obtokovou clonou potvrdili vyššie úspory iba v prípadoch, kedy rýchlosť doplňovacieho hydrogenerátora bola výrazne vyššia a prietok cez obtokovú clonu do skrine hlavného hydrogenerátora zabezpečil dostatočné chladenie. Najvyššie výkonové úspory boli dosiahnuté s premenlivým preplachovacím systémom, ktorého prietok sa menil podľa požiadaviek hydrostatickej prevodovky. Záver druhej časti práce sa zaoberá metodikou dimenzovania veľkosti doplňovacieho hydrogenerátora.

Hydropower is the most important power balancing resource in the Swedish electrical power system, regulating the power supply to match the load. Consequently, several hydropower plants have periods of stand-by operation where the power production is absent but where several devices within a plant are still active. Such a device is the step-up power transformer, which during stand-by operation still generates no-load energy losses. These losses can accumulate to a considerable amount of energy and costs during the long technical lifetime of the apparatus. One option to minimize these no-load energy losses is by turning the transformer off when its generating unit is in stand-by operation. However, when this transformer operational change has been explained to experts in the field, the most common response has been that a more frequent reenergizing of a transformer leads to higher risks for errors or transformer breakdowns. This study aimed to analytically investigate three effects from this operational change. First, the potential of fatigue failure for the windings due to the increased sequences of inrush current. Secondly, the thermal cycling as a consequence of change in present losses. Lastly, the energy and economic saving potentials for hydropower plants where this operational adjustment is applied. The study used both established as well as analytical tools explicitly created for this study. These were then applied on currently active transformers in different plant categories in Fortum’s hydropower fleet. The study primarily showed three things. Firstly, risk of fatigue failure due to the increased presence of inrush currents did not affect the transformer’s technical lifetime. Secondly, the thermal cycling changes were slightly larger with absent no-load losses during stand-by operation. The average temperature for the transformer decreased, which in general is seen as a positive indicator for a longer insulation lifetime and thus the transformer’s technical lifetime. Finally, the created frameworks showed the potential of saving energy and money for all plant categories, where the potential grew with the installed production capacity and the stand-by operation timeshare. Despite the simplifications made to describe the complex reality of a transformer operating in a hydropower plant, this thesis contributes to lay a foundation for future investigation of an easy adjustment to avoid unnecessary energy losses and costs for transformers in hydropower plants