Simhallar är en byggnadstyp med stor energianvändning. Härnösands simhall har en månatlig elenergianvändning på 100 000 kWh, vilket motsvarar fyra normalvillors årsanvändning. Arbetets syfte är att beräkna var energin används och se vilka energieffektiviseringsmöjligheter det finns för att minska användningen. Energikartläggningen har gjorts genom att samla in information från besök på anläggningen, driftkort, ritningar, avläsa värden på enheter, pumpar och värmeväxlare och prata med driftpersonal. Simhallen består av en 25-metersbassäng, en undervisningsbassäng, plaskavdelning, relax, gym och restaurang. Den renoverades under 2010. Härnösands simhall har en energifördelning och energianvändning som liknar genomsnittliga simhallar. Härnösand använder 2 700 MWh per år i total inköpt energi, där både fjärrvärme och el ingår. Den har en energianvändning på 13,6 kWh/besökare medan andra tidigare beräknade simhallar ligger mellan 8–24 kWh/besökare. Simhallen använder 50–100 kWh per timme under natten och 180 – 230 kWh under en timme då simhallen är öppen. Simhallen har ett över lag gott energitekniskt utformande. De områdena med tydligast potential för energieffektivisering är spillvatten från duschar, belysning och ventilation. Årligen spolas 200 000 kWh i avloppet med duschvatten. Det krävs troligtvis för stora insatser för att kunna tillgodogöra sig den energin. Belysningen och ventilationen har en del potential att kunna minska energianvändningen, men det har inte gått att beräkna.  Härnösands simhalls energi fördelas genomsnittligt och energianvändningen per besökare är genomsnittlig, jämfört med sju andra badhus. / Public baths are a high consumer of energy. Each month the electricity energy use in Härnösand’s public bath, Härnösands simhall, is close to 100,000 kWh, which is equivalent to four standard Swedish villas annual electricity consumption. The purpose of this thesis is to calculate where the energy is used in this public bath and to see if there are any possible energy efficiency measures. The public bath includes a 25 meters swimming pool, a teaching pool, a toddler splash pool area, a wellness area with warm pools and saunas, a gym, and a restaurant. The energy mapping has been made by visits, reading operating cards and drawings, collecting data values from units and heat exchangers, and talking to operating staff. Härnösand’s public bath has energy use similar to other Swedish public baths. The facility used 2,700 MWh of energy in 2022, district heating and electricity included, which is 13,6 kWh/swimmer, while other public baths use 8-24 kWh/swimmer. In one hour at night the facility uses 50-100 kWh per hour. An hour during opening hours the same value is 180-230 kWh. The facility is energy efficient well designed since renovated in 2010. Although there are three areas with the clearest potential in energy efficiency: shower wastewater, lighting, and ventilation. Annually, 200,000 kWh are flushed down the drain with shower water. It probably requires too much effort to be able to take advantage of it. The lighting and ventilation have some potential to reduce energy use, but it has not been possible to calculate. The energy use of Härnösand´s public bath is average compared to other Swedish public baths.

The aim of the study is to investigate whether induction devices can replace fan convectors, which is the climate system that is most common in hotel rooms today. The study compares the importance of the power of the two climate systems, induction devices and fan convectors, for use in hotel rooms. Climate systems controlled by presence require high power if room temperature is to be quickly regulated. The results show that fan convectors with power of 3000 W are often oversized for the hotel room, as the room being studied has a dimensioning cooling power requirement between 600 – 1700 W and heating power needs between 600 – 1000 W. Induction devices with a power of 1500 W are capable of meeting the cooling and heating needs if the room is appropriately designed according to its conditions, including sun protection and high window quality.    When the climate systems have been switched off during the absence period, the room has reached different temperatures depending on the design of the room. The time to cool or heat the room to the desired temperature, which is related to how hot or cold the room has been, differs between fan convectors and induction apparatus. High-power fan convectors have always been able to cool or heat the room in under 1.5 hours, while induction devices often can do it in a shorter time, except in cases where the power requirement is over 900 W.   What distinguishes the rooms studied is the placement of windows in different directions, the quality of the windows such as permeability, g-value and insulation ability, u-value, the rooms also have different thermal masses and sun shielding. The room that requires the highest heat output has a window with high g-value to get the most heat in during the winter months to reduce the power requirement, which turned out to have the opposite effect. When the permeability of light is high, it also contributes to more sunlight and heat being given to the room in the summer, therefore the cooling power requirement is also high for rooms with such a window.   To reduce the power requirement in an existing room, measures such as window replacement, additional insulation or sun protection change can be performed. The measures have different effects and can contribute up to 150 W lower power requirements, which means that both climate systems can be used in hotel rooms without problems.

Digesters at a biogas plant have high temperatures and poor insulation. There is great potential to save energy by improving the construction. This study has two aims. One is to compare the difference between a simple steady-state calculation and a calculation that uses simulated values from Heat2. The second is to develop an improved insulation method at the concrete digester that can be used in future projects. Ten different insulation scenarios have been simulated to understand how to improve the insulation method to develop an idea of where the insulation has the most impact. Then a combined insulation method was created from the scenarios. That combined method was then simulated with 5 different insulation thickness to find the most profitable design. The conclusion was that there is great value in making more advanced calculations for the walls and floor because the energy losses are very excessive using the simplified calculation, especially on surfaces covered in soil. It was proved difficult to calculate the losses for the roof, this was because the assumption that was needed to perform the calculation does not mirror the reality. Due to this, the roof has been neglected in the suggested insulation method. The insulation method proposed provides an energy saving of 58 MW h/year and a discounted payback time of 4, 3 years if the saved energy can be delivered as 90◦C degree hot water into the district heating network.

The Swedish energy supply has gone from dispatchable energy sources to more intermittent energy. The conversion to renewable sources such as solar and wind power, also the increasing demand caused by electrification of cars creates increasing challenges on today's electricity grid. Today's electricity consumption is an increasing trend, which puts loads on the electricity grid as reducing consumption is one of several solutions.  From 1 January 2022, the ordinance (2007:215) on exemptions from the requirement for a network concession in accordance with the Electricity Act (1997:857) has been amended. Construction of an internal low-voltage grid for energy sharing, also called microgrids, has been permitted. This enables an internal low-voltage network, sharing of energy that is burred underground and not overhead may be built, also to be used without a network concession for private actors to build microgrids. This report looks at the interconnection of photovoltaic systems in a microgrid, which enables the sharing of electrical energy. The aim of the study is to see conditions that are advantageous in applying a microgrid. The survey has been compared in two scenarios. Scenario 1 has four buildings with individual photovoltaic systems. Scenario 2 have the same four buildings but only two photovoltaic systems installed, on houses one and four. Both scenarios are compared with the application of a microgrid. The buildings are based on the planned residential area for Eksta AB in Algusered, Kungsbacka. The study in Algusered shows an increase in self-use and self-sufficiency as well as a reduction in overproduction and CO2 emissions for all facilities. Scenario 2 reduces investment costs by reducing the total installed solar cells.

Rapporten ämnar kartlägga beteendet för de vanligaste typerna av kylkompressorer, vid användning av köldmedier med låg GWP (global warming potential) under olika driftsförhållanden, samt att tillgängliggöra denna kartläggning i form av diagram och tabeller. Av de parametrar som utgör kartläggningen, så ligger huvudfokus på den isentropiska och volymetriska verkningsgraden. Alla de kompressormodeller som ingår i kartläggningen är antingen hermetiska eller semihermetiska. Det har i vissa fall varit omöjligt att ta fram den isentropiska verkningsgraden gällande dessa kompressormodeller. I dessa fall har den så kallade hermetiska verkningsgraden använts istället, vilken baseras på den elektriska effekten som kompressorenheten kräver. Kartläggningen är baserad på köldmedierna koldioxid (R744), propan (R290) och tetrafluoretan (R134a) i kombination med ett flertal kompressormodeller av typerna kolv och scroll. Katalogdata för dessa modeller erhölls via Select 8 och Coolselector 2; två beräkningsverktyg från tillverkarna Emerson och Danfoss. För att beräkna de parametrar som inte var tillgängliga via dessa beräkningsverktyg användes samband tillhörande den kompressordrivna förångningsprocessen. Slutligen sammanställdes insamlad och beräknade data i form av tabeller och diagram, där diagrammen utformades i stil med tidigare kartläggningar som förekommer i kurslitteratur på KTH. Det är fortfarande oklart om vad som i Select 8 benämns som ”isentropisk verkningsgrad” endast avser de mekaniska förlusterna som uppkommer under kompressionen, eller om alla förluster i kompressorenheten är inkluderade. Om fallet är det sistnämnda borde denna verkningsgrad ses som en hermetisk verkningsgrad (för semi-hermetiska eller hermetiska kompressorer) istället för enisentropisk. I denna rapport har tanken varit att separera den isentropiska verkningsgraden från den hermetiska verkningsgraden, eftersom så är fallet i den kurslitteratur som använts i rapporten. Däremot har samma termer som förekommer i de båda beräkningsprogrammen även använts i rapporten, vilket är anledningen till varför isentropisk verkningsgrad står utskrivet för de hermetiska och semihermetiskakompressormodellerna från Select 8. Det finns således en risk att vad som står som isentropisk verkningsgrad i denna rapport egentligen ska läsas som hermetisk verkningsgrad. Detta gäller för alla kompressormodeller som behandlats i Select 8. Sånär som på oklarheten som kvarstår kring betydelsen av den isentropiska verkningsgraden från Select 8, är rapportens syfte och delmål genomförda. / This bachelor thesis aims to chart the behaviour of modern compressors, using low GWP (global warming potential) refrigerants during different operating conditions. The aim is also to present the gathered data in form of diagrams and tables. The isentropic and volumetric efficiencies are the main parameters that have been used to chart the behaviour of the compressors in this project. In some cases, it has not been possible to calculate the isentropic efficiency regarding the semihermetic and hermetic compressor models that occur in this report. In these cases, the overall efficiency for a hermetic or a semi-hermetic compressor has been used instead. The overall efficiency is based on the total electric power input to the compressor unit. In order to chart the behaviour, three refrigerants were chosen in combination with different compressor models. The chosen refrigerants were carbon dioxide (R744), propane (R290) and tetrafluorethane (R134a), and the compressor models were of the types piston and scroll. The compressors models, in combination with the refrigerants, were chosen from the software tools Select 8 and Coolselector 2 provided by the manufacturers Emerson and Danfoss. The input variables consisted of two values for superheat and several values for condensing and evaporatingtemperatures. The compressor models used in this report are either hermetic or semi-hermetic. Some of the desired data was not available in the software and had to be calculated using well known equations regarding the vapor compression cycle with superheated suction vapor. Finally, both the collected and calculated data was compiled into tables and diagrams. The final shape of the diagrams was inspired by previous work available through mentioned course literature. It is still unclear if what is labelled as “isentropic efficiency” for hermetic and semi-hermetic compressors in Select 8 truly considers only the mechanical losses during the compression, or if it takes into account all losses in the compressor unit. If the latter, the efficiency should be considered as an overall efficiency for a hermetic or semi-hermetic compressor, not isentropic. The intention in this report has been to separate the isentropic efficiency from the overall efficiency regarding hermetic compressors, since these are two distinct efficiencies according to the course literature used. However, when an efficiency has been reported as “isentropic” by the manufacturer, it has also been labelled as so in the report. Therefore, if the efficiency is mislabelled in the software, it is also mislabelled in this report. A word of caution is therefore advised when taking part of these results, with regards to the isentropic efficiency whenever mentioned. Except for the confusion surrounding the meaning of isentropic efficiency in Select 8, the purpose and objectives of this bachelor thesis have been fulfilled.

Målet med denna studie är att ta fram en metodik och beräkningsmodell för att beräkna återladdningsmängd och dess effekter på ett bergvärmesystem som kan användas tillsammans med simuleringsverktyget för bergvärmesystem Earth Energy Designer (EED) och som kan hantera olika återladdningsmetoder. Syftet med studien är att automatisera och effektivisera beräkningen av optimal återladdning.  För att utföra detta skapades en beräkningsmall i Microsoft Excel. I mallen kan användaren importera effekter från den valda återladdningsmetoden, beroende på bergvärmesystemets värmebärartemperaturer. I de fall som återladdningeffekten är beroende av utomhustemperaturen kan även dessa importeras i mallen. Därefter, så kan användaren simulera bergvärmesystemet i EED där temperaturer beräknas. Dessa kan sedan importeras till beräkningsmallen och effekter beroende på de aktuella temperaturerna kan beräknas. Effekterna kan sedan bli exporterade till EED och bergvärmesystemet kan återigen simuleras och nya temperaturer uppstår. Denna process måste repeteras tills dess att konvergens uppnåtts och temperaturerna slutar ändras mellan simuleringarna. Den utvecklade beräkningsmodellen och metodiken har sedan tillämpats på en fallstudie där det projekterade bergvärmesystemet ska leverera värme till en förskola i Luleå kommun. Detta GSHP-system har 16 borrhål, dimensionerat för att möta förskolans värmebehov och därav är det väldimensionerat. På grund av implementeringen av återladdning så har antalet borrhål reducerats så att bergvärmesystemet blir underdimensionerat, effekterna av återladdning på detta system har utvärderats och jämförts med det väldimensionerade bergvärmesystemet. Fyra fall av återladdning har blivit implementerade. I samtliga fall har bergvärmesystemet återladdats med kylmedelkylare men återladdningseffekten och energin har varierat mellan de olika fallen.  Resultaten visade att genom återladdningen kan både temperaturen på värmebäraren i borrhålen och COP höjas. Detta leder till att energin som behöver tillföras värmepumpen minskar liksom driftkostnaden för densamma. Vid en ekonomisk analys för det väldimensionerade, underdimensionerade bergvärmesystemet utan återladdning samt de fallen där återladdning implementerats visade resultaten dock att den totala livscykelkostnaden blev större för de fallen med återladdning än de fallen utan. Detta beror på att både den totala drift och installationskostnaden för systemen blir större när återladdningen implementerats än när det inte görs. Detta trots att investeringskostnaden för borrhålen minskar när antalet borrhål minskar samt att energin som krävs till värmepumpen minskar när återladdning implementerats. Slutsatsen som kan dras av studien är att en beräkningsmodell och metodik för att beräkna återladdning och dess effekter på ett bergvärmesystem kunde skapas. Modellen och metodiken kan också användas tillsammans med EED för flera typer av återladdning men i denna studie har den enbart implementeras med en återladdningsmetod. Rörande effekterna av återladdning med den implementerade återladdningsmetoden på borrhålen, så visade resultatet att återladdning med kylmedelkylare i detta fall inte är ekonomiskt lönsamt och ska bara implementerats om det är något som krävs om det till exempel skulle vara begränsad yta för borrning av borrhål. Detta är dock något som måste beräknas i varje enskilt fall av återladdning.

This report gives a general overview of the natural gas resources in the world, along with its importance as a source of producing energy, and technical uses. It also draws attention to the political issues raised by natural gas exploitation and the steps being taken to address them. It also discusses the long-term measures required to achieve net zero emissions. With enormous supplies spread across several locations, natural gas is essential to the world's energy balance. Its better burning characteristics makes it a desirable substitute for other fossil fuels, especially for the production of power, heating, and industrial activities. Economic growth and global energy security are significantly impacted by the availability of natural gas resources. However, natural gas extraction and use, raise additional environmental issues, particularly in light of its greenhouse gas emissions have been discussed. Despite producing less carbon dioxide than either coal or oil, natural gas is a significant source of methane emissions, a powerful greenhouse gas. So a deep dive into why methane is a stronger greenhouse gas has been presented. It is observed that the fracking, flaring and methane leaks during the mining, transportation, and storage processes are the major concerns for climate change mitigation. Furthermore, natural gas is intertwined with political issues due to its geopolitical nature and the reliance of resource-rich nations on it as a significant source of income. It is observed that geopolitical tensions and potential wars are frequently caused by disagreements over ownership, cost, and transit routes. Geopolitical stability and energy security will be impacted by a region's reliance on imported natural gas. Various mitigation measures have been proposed and implemented to tackle the environmental challenges posed by natural gas are discussed. These include improving extraction techniques such as improved drilling methods and improved leak detection systems and investing in cleaner technologies, such as carbon capture utilization and storage (CCUS). Policies and rules are also being developed to encourage the use of advance energy efficiency measures and to promote the use of renewable energy sources in addition to natural gas. These measures aim to minimize the carbon footprint of natural gas and transition towards a more sustainable energy system. However, achieving long-term sustainability and net zero emissions (NZE) will require more profound transformations. To achieve NZE, EU has proposed the fit for 55 package. Some of the proposals of the fit for 55 package to achieve NZE 2030 target have been discussed. This involves developing alternative energy sources and technologies, such as renewable energy and the use of alternate fuels in various sectors. It also entails promoting energy conservation, implementing rigorous emissions regulations, fostering international cooperation, and investing in research and development for innovative solutions. Implementing all these measures ensure a sustainable and secured energy for future generations.

Due to concerns for climate change and future supply of phosphorus fertilizer within agriculture, there has been an increased interest in the combustion of phosphorus containing waste residues and opportunity biomass fuels. Previous research has shown that during combustion, phosphorus has large impact on ash transformation reactions and may decrease or increase ash-related problems such as slag formation and bed agglomeration. This is a serious concern if new types of biomass are to be added for heat and power production. Additionally, plant studies and leaching tests of P-rich biomass ash indicate that the plant availability of phosphorus varies greatly with its association in the ash. As such, the ash transformation behavior of phosphorus is of great importance for the success of such ventures. While several studies have been made on the behavior of phosphorus during combustion, no comprehensive study has been made evaluating the effect of fuel composition and combustion conditions. In this work, the behavior of phosphorus was determined for a wide range of fuels and combustion conditions. More specifically, the objective was to determine (i) the effect of fuel ash composition and combustion technologies on the fate of phosphorus during combustion, (ii) investigate potential difference in the behavior of phosphorus during combustion of sewage sludge and plant based biomassand (iii)the effect of phosphorus on slag formation and bed agglomeration for the co-combustion of a wide range of plant based biomasses. The investigation was carried out by comparing experimental data gathered from the combustion of 26different biomass fuelsor fuel blends in a bench scale bubbling fluidized bed (5 kW, 18 experiments), an underfed pellet burner (20kW, 10 experiments) and a swirling powder burner (150 kW, 7 experiments). This included chemical characterization of bed ash, bottom ash and fly ash fractions by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) in addition to qualitative measures of slagging-and bed agglomeration tendencies. It was found that phosphorus, irrespective of combustion technology and fuel composition, was mainly found in bed-, and bottom ash fractions and/or coarse fly ash fractions (>1μm). Based on the crystalline phase composition of the phosphates found in bed-, bottom-and coarse fly ash samples, phosphate speciation was correlated to the molar ratio between P, Ca and Mg for all three combustion technologies. Based on these results, it would be possible to control the behavior of phosphorus during combustion and the plant availability of phosphates in biomassash by designing fuel blends based on their fuel ash composition. In fluidized bed combustion, it was found that for similar combustion conditions and fuel ash compositions (with respect to K, Ca and P), the speciation of phosphorus in coarse ash fractions was significantly different from experiments with plant based biomass compared to sewage sludge. Unlike ash from plant based biomass, the crystalline phase composition of ash from sewage sludge did not change with the relative concentration of K, Ca andP in the fuel. The results suggest that the reaction pathway of phosphorus during combustion of sewage sludge is different to plant based biomass due to difference in the association of phosphorus in the fuel. The effect of phosphorus on slag formation and bed agglomeration in biomass combustion was mainly related to the relative fuel ash concentration of K, Ca, Mg, Si and P. In fluidized bed combustion, P contributes to the formation of agglomerates through the melt induced mechanism, through complex interaction with K, Ca, Mg and Si. Similarly, in fixed bed combustion the composition of slag indicatedthatslag formation involves the formation of P and Si rich ash melt with a varying content of K, Ca and Mg. In both cases, the severity of problems was related to the melting behavior of the (CaO,MgO)-K2O-(SiO2,P2O5) multicomponent system.

This thesis summarises the work performed within the project known as ICE-COOL at the Royal Institute of Technology (KTH) on low tem-perature applications of ice slurry. The ICE-COOL project is a Euro-pean Community funded project within the 5th Framework Program. The task given to KTH was to find and characterize the best possible aqueous solution with a freezing point of -25 °C applicable for ice slurry with an operating temperature of -35 °C. The circumstances differ for low temperature ice slurry from medium temperature as a result of for example the change in thermo-physical properties due to increased addi-tive concentration and the lower temperature. Ice slurry is a mixture of fine ice crystals, water and freezing point de-pressant additives. The typical ice crystal size ranges between 0.1 to 1 mm in diameter. The main purpose of using ice slurries is to take advan-tage of the latent heat. More than a few requirements are to be fulfilled by an ideal ice slurry fluid. It should have good thermo-physical proper-ties, high heat transport and transfer abilities, as well as low pressure drop to facilitate small pumping power. The ice content of ice slurry af-fects all the mentioned abilities. Apart from the mentioned factors of the fluid, there are other aspects that have to be taken into consideration such as environmental pollution and toxicity, flammability, material compatibility, corrosion, handling security and cost. This thesis reports on the experiences accomplished and the initial ex-periments performed on low temperature ice slurry. The thesis also gives the background and fundamentals necessary for a discussion and com-parison of different aqueous fluids suitable for ice slurry in general and for low temperature in particular. In addition to the low temperature ap-plication, the thesis also reports on an initial energy consumption com-parison between using ice slurry and single-phase fluid in supermarkets by means of the simulation program CyberMart developed by Jaime Arias at the Department of Energy Technology at KTH. / QC 20101202

Industry is responsible for approximately 30 % of the total emissions of greenhouse gases, both globally and in Sweden. Given the climate targets set out in the Paris agreement, the industry is facing a challenging future, requiring effective policies to aid the transition. Energy system optimisation models are commonly used for analysing the impact from different policies and for assessing the transition to a climate-neutral energy system. In the past, the primary focus of the models has been on the stationary energy sector, and less on the industry. This thesis work, therefore, aims to improve energy system optimisation models as a tool for decision support and policy analysis about the industry. An improved modelling structure of the industry sector is developed and a wide range of future technology options that can support the transition to a climate-neutral industry is identified. The improved model is then applied in different scenario analysis, assessing how the Swedish industry can meet net-zero CO2-emission under resource limitations. The methodology applied is energy system analysis with a focus on the process of modelling, an iterative process of i) model conceptualisation, ii) model computation and iii) model result interpretation. Two different models for the evaluation of the Swedish industry are developed and used; a TIMES based model (cost-minimisation) and a small linear optimisation model (resource optimisation). An outcome from developing the model structure was that the following important aspects need to be represented in the model to capture the transition to a climate-neutral industry sector; i) synergies between different types of industrial processes, ii) setup of process chains based on important tradeable materials, iii) detailed technology representation. When identifying and analysing future technologies, it was concluded that there are plenty of technology options for Swedish industry to become fossil-free. Technology options were identified that enable all studied site categories (representing approximately 92 % of the CO2 emissions from Swedish industry in 2015) to reach net-zero CO2-emissions via either electrification (direct electric heating or via power to gas) or biofuels usage. CCS options were implemented for iron and steel industry, chemical industry, cement- and limestone industry and aluminium industry, and for most of the industrial energy conversion technologies. Although technology options for deep reductions in CO2 emissions exist, many of them require further development to enable full-scale implementation, as concluded in paper III. The scenario analysis performed in paper I and paper II gives insights into key resources and technologies enabling the industry to reach net-zero CO2 emissions. About resources, biomass is seemingly the most cost-efficient option for reaching ambitious climate targets, e.g. according to the findings in paper II biomass is consistently preferred over electrified alternatives. However, the availability of biomass is limited, and increased electrification of technologies is unavoidable to achieve sustainable use of it (as seen in paper I and paper II). Finally, there is not one key enabling technology but rather key groups of enabling technologies that create cross-technology synergies, providing different benefits depending on resource availability and the overall needs of the system in different scenarios.