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.

Organisk Rankine cykel är en förångningscykel med användningen av en organisk fluid för att få bättre lågtempererade egenskaper än vid användningen av vattenånga. Naturgas är ett bränsle som används inom industrin och sjöfarten, den förvaras mycket kallt i vätskeform för att spara utrymme. Detta bränsle förångas antingen naturligt eller med syftet att förbränna den i gasform. Detta för att minska behovet av kryogenisk teknik. Förångningen sker med att tillföra värme till bränslet. Genom att förgrena ångcykelns behov av kondensering och bränslets behov av värme kommer massflödet för kondenskylningen att minska. Det ger i sin tur en stadigare drift i varma miljöer. Frågeställningen var hur mycket effekt som kunde hämtas ur denna konfiguration. Hur mycket mindre kondenseringsanläggningen blir och den möjliga systemkonfigurationen utifrån aspekten av säkerhet, effekt och goda möjligheter till reglering. Tillvägagången var först att studera systemen ingående, hur de funkar och för att ta fram de fysikaliska data. Sedan teoretiskt bygga samman systemen och göra beräkningar. Resultatet påvisade låg effekt men med ett behov av en 11 gånger mindre kondensor jämfört med vattenkylning. Slutsatsen är att denna konfiguration begränsar den potentiella effekten mycket men minskar effektbehovet för att driva ångprocessen och att kondenseringsanläggningen blir mindre. / Organic Rankine cycle is a vaporization cycle where an organic fluid is used toobtain better low-temperature properties than when using water vapor. Natural gasis a fuel used in industry and shipping it is stored very cold in liquid form to savespace. This fuel is either vaporized naturally or with the aim of burning it in gaseousform. This is to reduce the need for cryogenic technology. Vaporization takes placeby adding heat to the fuel. By branching the steam cycle's need for condensation andthe fuel's need for heat, the mass flow for condensation cooling will decrease. Thisin turn provides a more stable operation in warm environments. The question washow much power could be extracted from this configuration. How much smaller thecondensing plant will be and the possible system configuration from the aspect ofsafety, power, and good solutions for control. The approach was to first study thesystems in detail, how they work and to produce the physical data that was required.Then theoretically build the systems together and make calculations. The resultshowed low power but with a need for an 11 times smaller condenser compared towater cooling. The conclusion is that this configuration greatly limits the potentialpower but reduces the power requirement to drive the steam process and thecondensing plant becomes smaller.

Extena är en industri som ligger i norra Sverige. Det producerar tryckrörsledningar vilket leder till en stor mängd spillvärme i kylvattnet som inte används hos Extena i dagsläget. Fabriken använder samtidigt elbatterier för uppvärmning av ett par lokaler på industriområdet. Syftet med projektet är att undersöka möjligheteten att energieffektivisera Extena genom att ta vara på energin som finns i spillvattnet. Målsättningen med arbetet är att ge underlag för en energieffektivare uppvärmningslösning för vidareförädling och underhållsverkstad. Men även undersöka möjligheten till att exportera värme till närliggande samhälle genom att beräkna värmetransportförluster till Norsjö centrum för att effektivisera processen på fabriken och ta vara på så mycket energi som möjligt. Genom att ta vara på spillvärmen från produktionen kommer också belastningen på kyltornen minska vilket gör underlättar för processen. Uppvärmningen av egna lokalerna kommer ske med kulvert från kylvattenbassängen till vidareförädling och underhållsverkstaden med en vattentemperatur på ungefär 15  . Det används för att beräkna värmepumpens  . Den nya värmepumpen kommer kräva ett vattenburet system för att sprida värmen i lokalen. Det undersöks främst på fläktkonvektorer. Uppvärmning för lokalen är okänd vilket måste antas vilket ger den årliga uppvärmningen av 104 696 kWh som används för beräkning av livscykelanalys och ekonomisk återbetalningstid.  Möjligheten att bygga ett nytt närvärmenät för Extena utvärderas genom att beräkna värmeledningsförluster för olika rörledningar. Det görs med ett webbaserat datorprogram Logostor. Där det visar sig att TwinPipe systemet ger minst värmetransportförluster.  Resultatet beskriver ifall installation av värmepump är en bra investering. Det beräknas genom energibesparingen som är 83 757 kWh/år. Det används för att beräkna återbetalningstiden miljömässigt till ungefär ett halvt år, samtidigt som den ekonomiska återbetalningstiden är 5 år och 6 månader för ett elpris på 0,5 kr/kWh. Möjligheten att transportera spillvattnet till en annan aktör kan ske på flera sätt som undersöks, där ett nytt närvärmenät är rimligast eftersom fjärrvärmenätet kräver högre temperaturer och har större förluster. Närvärmenätets värmetransportförluster från fabriken till någon av kommunens byggnader som beräknas ligga 2100 meter ifrån. Det totala värmetrasportförlusterna är 311 MWh av det totala energimängden 870 MWh som finns i spillvattnet efter kylprocesserna. Flödet av spillvatten sker endast 4300 timmar årligen vilket gör att det är svårt att använda som ensam uppvärmning för lokaler.

Syftet med detta arbete var att undersöka om olika utökningar av ett passivt borrhålslager kan påverka dess långsiktiga prestanda ur ett ekonomiskt samt ett tekniskt perspektiv. Målet var att genom överdimensionering av borrhålslagret försöka sänka de långsiktiga driftkostnaderna och därmed minska dess totala livscykelkostnader samt förlänga lagrets tekniska livslängd.  För detta gjordes en fallstudie på ett projekterad borrhålslager belägen i Luleå kommun som projekterades av WSP till Alviksskolans alternativa bergvärmeanläggning. Borrhålslagret som från början består av 16 borrhål vardera med 300 meters djup utökades eller överdimensionerades genom addering av borrhål samt ökning av dess totala djup. Kombinationerna av dessa utökningsalternativ sammanställdes i olika fall som sedan utvärderades ekonomiskt samt tekniskt ur ett långtidsperspektiv. Fem olika fall undersöktes där ett borrhål adderades för varje fall med 16 borrhål som utgångspunkt i det första fallet upp till 20 borrhål i det femte fallet. Dessa kombinerades med tre olika borrhålsdjup på 300,- 350- samt 400 meter. Genom att addera borrhål samt öka dess totala djup kan medeltemperaturen av i borrhålslagret cirkulerande köldbärarvätskan ökas samt dess nedkylningstakt med åren minskas som kan förbättra bergvärmesystemets långsiktiga prestanda. Förbättringen av prestandan medför minskad energikonsumtion och därmed sänkta driftkostnader som under en längre tid kan medföra sänkta livscykelkostnader. För att se hur köldbärarvätskans temperatur i borrhålslagret påverkas hos de utökade fallen simulerades dess temperaturutveckling med hjälp av programvaran EED. Utifrån de simulerade temperaturprofilerna hos de utökade borrhålslagren räknades sedan den teoretiskt maximala COP ut samt dess degraderingstakt med tiden som för varje undersökta fall jämfördes med den ursprungligen projekterade lagrets uträknade maximala COP och dess degraderingstakt. På så sätt räknades en teoretisk procentuell förbättring fram av systemets långsiktiga prestanda hos de överdimensionerade fallen. Av dessa kunde sedan minskandet av energikonsumtionen hos de utökade fallen räknas ut varav dess livscykelkostnader kunde beräknas. Temperaturutvecklingen av köldbärarvätskan som simuleringarna visade hos de undersökta fallen plottades också upp i grafer för att se hur borrhålslagrets tekniska livslängd påverkas av de applicerade utökningarna.  Resultaten visar att det långsiktigt inte är lönsamt att överdimensionera ett borrhålslager utifrån de beräknade livscykelkostnaderna. Hos alla de studerade fallen är livscykelkostnaderna av de överdimensionerade borrhålslagren alltid högre än av den ursprungligen projekterade borrhålslagret vilket resulterar alla dessa i ekonomiska förluster i slutändan. Det beror på de höga extra investeringskostnaderna som olika utökningar av borrhålslagret medför vilket inte kan kompenseras av den minskade energikonsumtionen. Tekniska livslängden förlängs däremot hos alla utökade fall vilket är en teknisk fördel som kan framtidssäkra borrhålslagret. Generellt presterar utökning mot djupet bättre än utökning av adderade borrhål både ur ett ekonomiskt och ett tekniskt perspektiv. Då energikonsumtionen minskar hos alla de undersökta utökade fallen blir också borrhålslagret mindre beroende av extern elproduktionen som indirekt kan minska användningen av fossila bränslen. Reducering av fossila bränslen till elproduktion kan därmed mildra koldioxidutsläppet och sakta ner globala uppvärmningen. Slutsatsen som kan alltså dras är att överdimensioneringen av ett borrhålslager i norra Sverige är ekonomiskt inte en fördelaktig investering på grund av de höga investeringskostnaderna som detta medför. Förlängningen av den tekniska livslängden samt minskandet av externa elproduktionen kan däremot vara fördelaktigt i längden.Arbetet begränsas av just den specifika fallstudien som görs på Alviksskolans projekterade bergvärmeanläggning. Den specifika platsen gör att endast unika utformningar kan appliceras på den tillgängliga ytan som tillsammans med platsspecifika klimatet gör att resultaten av denna studie inte kan generaliseras för andra borrhålslager belägna på andra platser. Framtida arbeten inom ämnet skulle därför kunna undersöka överdimensioneringar i andra klimat samt utvärdera långsiktiga effekterna av färre borrhål i kombination med djupare borrningar. / The purpose of this work was to investigate whether different expansions of a geothermal borehole field can affect its long-term performance from an economical as well as a technical perspective. The goal was to try to reduce the long-term operating costs and reduce its total life cycle costs by over-dimensioning the borehole field, as well as extending its technical lifetime. For this, a case study was made on a projected borehole field in Luleå municipality which was designed by WSP for Alviksskolan's alternative ground source heat pump (GSHP) system. The borehole field, which initially consists of 16 boreholes each with a depth of 300 meters, was expanded or over-dimensioned by adding boreholes and increasing their total depth. The combinations of these expansion options were compiled in different cases, which were then evaluated economically and technically from a long-term perspective. Five different cases were investigated where a borehole was added for each case with 16 boreholes as a starting point in the first case up to 20 boreholes in the fifth case. These were combined with three different borehole depths of 300, 350 and 400 meters. By adding boreholes and increasing their total depth, the average temperature of the coolant circulating in the boreholes can be increased and its cool-down rate reduced over time, which can improve the long-term performance of the GSHP system. The improvement in performance leads to reduced energy consumption and thus lower operating costs, which over a longer period can lead to lower life cycle costs. To see how the temperature of the coolant in the boreholes is affected when the cases are extended, its temperature development over time was simulated using the EED software. Based on the simulated temperature profiles of the extended borehole fields, the theoretical maximum COP and its degradation rate over time were then calculated, which for each investigated case were compared with the calculated maximum COP of the originally dimensioned borehole field and its degradation rate. In this way, a theoretical percentage improvement of the system's long-term performance in the oversized cases could be achieved. From these, the reduction in energy consumption of the extended cases could then be calculated, from which its life cycle costs could be acquired. The temperature evolution of the coolant obtained from the simulations of the investigated cases was also plotted in graphs to see how the technical life of the borehole layer is affected by the applied expansions. The results show that in the long term it is not financially profitable to oversize a well-dimensioned borehole field based on the calculated life cycle costs. For all the studied cases, the life cycle costs of the oversized variants are always higher than for the originally dimensioned borehole field, which results all these in financial losses in the long-term. This is due to the high additional investment costs that various expansions of the borehole field entail, which cannot be compensated by the reduced energy consumption. However, the technical lifetime is extended in all the extended cases, which is a technical advantage that can future proof the borehole field. In general, expansion towards depth performs better than expansion of added boreholes from both an economic and a technical perspective. As energy consumption decreases in all the investigated expanded cases, the borehole also becomes less dependent of external electricity production which can indirectly lower the usage of fossil fuels. Reduction of fossil fuels for electricity production can thus mitigate CO2 emissions and slow down global warming. The conclusion that can thus be drawn is that the over-dimensioning of a borehole field in northern Sweden is not economically an advantageous investment due to the high investment costs involved. The extension of the technical lifespan and the reduction of external electricity production can, however, be beneficial in the long run.The work is limited by the specific case study that is done on Alviksskolan's projected GSHP system. The specific location means that only unique designs can be applied to the available land area at the school which together with the site-specific climate means that the results of this study cannot be generalized to other borehole fields in other locations. Thus, future work on the subject could investigate oversizing in other climates as well as evaluate long-term effects of fewer boreholes in combination with deeper drilling.

Mitthem är ett fastighetsbolag som ägs av Sundsvalls kommun och har ca 5 800 lägenheter.  Syftet med studien är att förutse hur elanvändningen och den ekono-miska kostnaden kommer att påverkas i framtiden med elbilar och mo-torvärmare. Studien ska visa när effekttopparna blir och hur batterilag-ringen kan kapa ner effekttopparna. Studien visar hur mycket produce-rad el som tillverkas med solceller från data från en annan solcellsanlägg-ning.  Studien inledes med att bygga en beräkningsmodell i Excel som är base-rad på insamlade data från producerad el från solceller, elanvändning från fastigheter och garage även historiska elpriser från elmarknaden. Med ett antagande med elanvändning av elbilar och motorvärmare.  Solcellerna kommer att producera 151 670kWh/år och ha en lönsamhet på 59 503kr/år. Batterilagringen kommer inte vara lönsam även om priser på batterilagring sjunker med 50 %.  Slutsatsen i studien är att elanvändningen ökar och effekttopparna blir högre i framtiden. Solceller har en lönsamhet i de olika driftfallen men batterilagringen är inte lönsam idag och även om priset sjunker med 50 % så är det inte lönsamt. All producerad el kommer att förbrukas till fastigheter och garage. / Mitthem is a real estate company owned by the Sundsvall municipality which has about 5,800 apartments. The purpose of the study is to predict how energy consumption and the economic cost will be affected by elec-tric cars and engine heaters in the future. The study will also show when the peak loads will occur and how battery storage can cut down these peaks. The study also shows how much electricity solar cells can generate from actual data.  The study began by building a calculation model in Excel based on col-lected data from electricity produced by solar cells, energy consumption from buildings and garages, as well as historical electricity prices from the electricity market. The solar cells will produce 151,670 kWh/year and have a profitability of 59,503 SEK. Battery storage will not be profitable even if battery storage prices drop by 50 %.  The conclusion of the study is that energy consumption increases and peak loads will be higher in the future. Solar cells have profitability in the different operating cases but battery storage is not profitable today, and even if the price drops by 50 %, it is not profitable. All produced electricity will be used for buildings and garages.

Gas turbines integrated with biomass gasification in a combined cycle power plant (Bio-IGCC) provide a path to power production with very high efficiency. Over 60% fuel-to-power efficiency has been demonstrated with natural gas. The fast ramp and relatively low cost make Bio-IGCC via gas turbines the ideal complement to intermittent power from wind turbines and PV cells. With stricter pollutant regulations and in order to promote the use of renewable fuels there is a great interest in improving fuel flexibility. An important feature of biomass gasification is that its properties vary depending on the feedstock and gasification principle and that the combustion characteristics are significantly different from conventional fuels. This makes it interesting to develop CFD models that can be used to simulate the combustion of syngas in existing gas turbines and for design optimization of new gas turbines.  The TECFLAM swirl burner geometry, which is designed to be representative of common gas turbine burners, was selected for an assessment of the differences between a typical hydrocarbon fuel and syngas. A two-stage approach was employed with development and validation of an advanced CFD model. The validated model was used to compare the flame shape and other characteristics of the flow between methane, 40% hydrogen enriched methane and four typical syngas compositions. The syngas compositions used are representative of practical gasification processes and biomass feedstocks. It was found that the syngas fuels experience lower swirl intensity due to high axial velocities that weaken the inner recirculation zone. A strong correlation was found between the laminar flame speed and the flame shape.  The simulation of a typical combustion geometry with syngas is quite demanding and requires a long computational time. In order to speed up the parametric analysis and to make it possible to test more configurations a Two-Step, One Way coupled method was assessed. This is a common approximation in CFD that is used to solve complex problems with limited computational resources. The test case used for the assessment was the CeCOST burner that uses strong swirl for flame stabilization. Only isothermal flow was investigated to eliminate the influence from flow – chemistry interactions. This method effectively divides the domain in two parts, one downstream and one upstream. The assumption behind this method is that the downstream part should not have a big influence on the upstream part and hence it could be solved separately. From the comparison it was found that the full solution and the approximations were in good qualitative agreement. However, there were some minor quantitative discrepancies, and it was proposed that the explanation for the differences could be the slightly different solution approaches that were used for the full simulation (URANS) and the two approximate solutions (RANS). The speed-up from using the approximate method was close to one order of magnitude.  However, because an artificial steady inlet cannot reproduce all the dynamic phenomena created by a swirler, for the continuation a full CeCOST domain was used. LES modelling was also employed to be able to identify smaller structures that would affect flame stability. Using LES and the Artificially Thickened Flame model, a syngas composition that relates to Black Liquor gasification was modelled. The flame front position using the CH2O mole fraction was estimated and it correlated well with the position estimated by the progress variable. The flame front position found by using the OH mole fraction was different to the two previous ones, predicting the hot part of the flame.

Den globala uppvärmningen blir en alltmer central fråga i samhället i takt med att det 1,5°C- mål som sattes i Parisavtalet kommer allt närmre. Mot bakgrund av denna växande oro har EU under energikrisen 2022/2023 enats om att främja energieffektivisering, och poängterar dess vikt för att bland annat uppnå en hållbar energiproduktion och minska den negativa klimatpåverkan en stor energikonsumtion medför. I dagsläget går ungefär hälften av en byggnads totala energiförbrukning till uppvärmning. För flerbostadshus i Sverige motsvarar det ca 29 TWh/år där energiförluster kopplat till ventilation utgör en större del. I denna parameterstudie undersöks hur isoleringen på ute- och avluftskanaler påverkar energiförluster i ett flerbostadshus placerat i Karlstads temperaturzon då tjockleken varierar mellan 0-80mm. Energiförluster har räknats i form av ett ökat uppvärmningsbehov inomhus då avluft oavsiktligt värms upp i avluftskanaler. Samtliga lägenheter i undersökt referensbyggnad är utrustade med individuella FTX-aggregat och tillhörande ventilationskanaler. Frågeställningen har analyserats i Comsol Multiphysics 6.1. Resultatet visar att det vid oisolerade ventilationskanaler årligen går förlorat 20MWh. Adderas 80mm isolering minskar förlusterna till 10MWh/år. Det motsvarar 2,5% av en byggnads totala uppvärmningsbehov för inomhusluft och tappvarmvatten. Om den initiala isolertjockleken i stället är 30mm och utökas till 80mm ges en total uppvärmningsbesparing på 0,3%. Energibesparingen blir procentuellt större vid tilläggsisolering ju kallare luft som rör sig i kanalerna. Störst energivinning görs alltså för byggnader i kallare klimat och vid användning av effektiva värmeväxlingsaggregat. Den maximala miljömässiga besparingen till följd av ett minskat uppvärmningsbehov, räknat i koldioxidekvivalenter, fås då 80mm isolering adderas på oisolerade kanaler och uppvärmning sker med direktverkande el. Besparingen uppgår då årligen till 1000kg. Motsvarande besparing då uppvärmning sker med fjärrvärme är 600kg årligen. Denna siffra tar ej hänsyn till klimatpåfrestning av tillverkning, hantering och transport av isolermaterialet. Energibesparingen avtar för varje cm isolering som adderas men för samtliga fall mellan 10-80mm uppnås lönsamhet då återbetalningstiden är kortare än isoleringens uppskattade livslängd. Snabbast återbetalningstid är efter 5 år då 30mm isolering används. Långsammast återbetalningstid är efter 11 år vid användning av 80mm isolering. 80mm isolering ger däremot den bästa ekonomiska avkastningen sett till hela isoleringens livslängd. I resultatet redovisas hur verkningsgraden för FTX-aggregatet sjunker från angivna 80% till mellan 61–70% beroende på isolertjocklek då transmissionsförluster till ventilationskanalerna medräknas. / Global warming is becoming an increasingly central issue in society as the 1.5°C target set in the Paris Agreement draws ever closer. Against the background of this growing concern, the EU has agreed during the 2022/2023 energy crisis to promote energy efficiency, and emphasizes its importance for, among other things, achieving sustainable energy production and reducing the negative climate impact that large energy consumption entails. Currently, about half of a building's total energy consumption goes to heating. For multi-apartment buildings in Sweden, this corresponds to approximately 29 TWh/year, where energy losses linked to ventilation form a larger part. In this parameter study, how the insulation on outside and exhaust air ducts affects energy losses in an apartment building located in Karlstad's temperature zone is investigated when the thickness varies between 0-80mm. Energy losses have been calculated in the form of an increased heating requirement indoors when exhaust air is unintentionally heated in exhaust ducts. All apartments in the investigated reference building are equipped with individual FTX units and associated ventilation ducts. The question has been analyzed in Comsol Multiphysics 6.1 The result shows that with uninsulated ventilation ducts, 20MWh is lost annually. Adding 80mm insulation reduces the losses to 10MWh/year. It corresponds to 2.5% of a building's total heating needs for indoor air and domestic hot water. If the initial insulation thickness is instead 30mm and is increased to 80mm, a total heating saving of 0.3% is given. The energy savings are percentage-wise greater with additional insulation, the colder the air that moves in the ducts. The greatest energy gains are thus made for buildings in colder climates and when efficient heat exchange units are used. The maximum environmental savings as a result of a reduced heating need, calculated in carbon dioxide equivalents, is obtained when 80mm insulation is added to non-insulated ducts and heating takes place with direct-acting electricity. The saving then amounts to 1000kg annually. The corresponding saving when heating is done with district heating is 600kg annually. This figure does not take into account climate stress from the manufacture, handling and transport of the insulation material. The energy saving decreases for every cm of insulation that is added, but for all cases between 10-80mm, profitability is achieved as the payback time is shorter than the estimated life of the insulation. Fastest payback time is after 5 years when 30mm insulation is used. Slowest payback time is after 11 years when using 80mm insulation. 80mm insulation, on the other hand, gives the best economic return in terms of the entire lifespan of the insulation. The result shows how the efficiency of the FTX unit drops from the specified 80% to between 61–70% depending on insulation thickness when transmission losses to the ventilation ducts are included.

When practicing their profession, engineers use their analytical and creative thinking to develop solutions for problems that require the application of scientific knowledge and experience in a dependable and sustainable way. Laboratory exercises represent an ideal scenario for engineering students to comprehend through the application in actual situations of fundamental concepts and to analyze, synthetize, and make judgments based on evidence. Furthermore, in case of group work, students collaborate on an assignment taking decisions and sharing responsibilities thus training their social skills. The use and development of information technology have in the past few decades increased at a very high pace and have had considerable effects on various domains of society, including education. Although distance learning has existed for a while, it is the widespread access to the Internet and familiarity of the current young generation with information technology that has led to the recent boom of interest in massive open online education (MOOC) as well as in various forms of blended learning. Laboratories in education are traditionally hands-on activities carried out on-campus by students with the assistance of an instructor. New laboratory environments such as virtual and remote laboratories have in the past decades been introduced in several disciplines to improve access to distant students, cut down costs, and reduce obsolescence of hands-on labs. Yet many are the doubts concerning their effectiveness in tackling the development of engineering skills, as well as their technical capability of being 24/7 worldwide accessible professional remote infrastructures. The present thesis work is concerned with the conceiving, implementation and evaluation of a set of remote laboratories to be used in the training of turbomachinery engineering students. The focus is put on three new remote laboratory exercises: a pump laboratory exercise focusing on the assessment of operation of pumps a turbine cascade laboratory exercise focusing on the measurement of aerodynamic losses and a turbine cascade laboratory exercise focusing on the measurement of aeroelastic properties in a vibrating blade row. The laboratories are developed using state-of-the-art instrumentation and a design that allows for reusability of common hardware and software resources. Different technologies are explored for the remote operation of the equipment while laboratory exercises are constructed that include interactive learning material, online self-assessments, and tools for analysis of the experimental test data. Extensive field-testing within ongoing courses at the department proves an overall good technical performance of the remote laboratories. Accessibility is significantly improved with the use of new web technologies while integration in existing networks of remote laboratories and use of remote experiment management systems is perceived as necessary for future scaling up of the application. The concept of the remote laboratory exercises is critically evaluated and leads to changes in the structure of the exercises that improve development of certain laboratory skills and student’s perception of the remote experience. The same experimental setup is used to address different learning outcomes and, in turns, different target audiences showing the potential of significantly improving the economical sustainability of the labs, especially in the case these are integrated in courses at other universities. The generality of conclusions is partially validated by the involvement of external students, researchers and professional in energy technology in the testing of the remote laboratory exercises as part of collaborative initiatives that raise also the interest for a possible application of remote experimentation in research activity. Keywords: remote laboratory, distant education, engineering education, turbomachinery training / <p>QC 20131206</p>