Denne oppgaven har sett på modellering av spredning og fordamping av dammer på faste underlag bestående av kryogene væsker. En modell basert på grunt vann-ligningene har blitt utledet. Grunt vann-ligningene består av: én kontinuitetsligning og to impulsligninger i henholdsvis x- og y-retning. Modellen tar høyde for varmeovergang, avdamping og todimensjonal spredning av dammen. I tillegg inkluderes viskøse krefter som påvirker spredningen. Ligningene som oppstår fra modelleringen løses numerisk. For å gjøre dette har det blitt skrevet et numerisk program i Fortran 90. Programmet har blitt kalt CRYOSPREAD og de numeriske teknikkene dette programmet bygger på gås gjennom i teksten. Det har også blitt gjennomført simuleringer med dette programmet. Simuleringene sammenlignes med henholdsvis forsøksdata og modeller i Kameleon FirEx (KFX). Ved å sammenligne med forsøksdata fra spredning av vann, vises det at dam-spredningsmodellen i CRYOSPREAD er kapabel til å følge forsøksdataene rimelig bra. Dette er imidlertid svært avhengig av en turbulenskonstant som representerer mye av usikkerheten i modellen. Sammenligning med spredningsmodellen av dammer i KFX viser tydelig forbedringen ved å løse impulsligninger. Et simuleringsforsøk med begge modellene har blitt gjennomført, der strømningen i starten skal være dominerende i én retning. Resultatet viser at dammen i KFX-modellen med én gang sprer seg mer radielt og ikke har en dominerende retning for spredningen til forskjell fra den nye modellen i CRYOSPREAD. Forsøksdata for avdampingsrater av metan og nitrogen uten spredning viser at avdampingsmodellen i CRYOSPREAD presterer rimelig bra for senere tider (t > ~20s), men har noe avvik i starten. Sammenligning med avdamping i KFX uten spredning viser den kvalitative forskjellen i avdampingsratene som følger av forskjellige modeller for varmeoverføring. Total avdampet masse fra dammen i KFX er proporsjonal med tiden, mens den er proporsjonal med t1/2 i CRYOSPREAD. Forskjellen består i at KFX ikke tar hensyn til kjøling av underlaget, mens modellen i CRYOSPREAD tar hensyn til dette gjennom en vertikal konduksjonsmodell i bakken. Da det ikke lyktes å få tak i forsøksdata for spredning og avdamping av kryogener er ikke modellen tilstrekkelig validert, men vil kunne gi en god pekepinn for hva som skjer ved spredningsulykker av kryogener hvis antagelsene den bygger på er gode nok.

A literature study is first presented then the practical experiments are described. The theoretical chapter provides an overview of filtration mechanisms and available gas cleaning technologies, with an emphasis on hot gas and cake filtration. The experimental chapters describe the setup and testing of the filter tray test rig and the L10-56 test rig.The filter tray test rig was built, instrumentation was installed and programming performed. Puff-back calibration and heating tests were performed. The puff-back calibration showed that a significantly lower delta p minimum was obtained with this design compared to previous designs. Filtration tests were conducted at an elevated temperature (120 C) with different dust concentrations (1 and 3 g/m3) and filtration velocities (10 - 20 cm/s). The results showed that the rig was working in accordance with the design criteria, with a filtration efficiency above 99,5%.A previously used filter test rig, the L10-56 test rig, was installed at the slipstream of the exhaust of a oil sand extraction pilot plant at 350⁰C. A horizontal bed unit (HBU) was also developed to investigate the impacts of the exhaust gas on the granular filter media. Once completed, the rig was re-tested and the puff-back calibration and heating tests that were performed achieved results corresponding with the previous testis performed on this test rig. The test rig was ready to start filtration tests but they were not initiated due to time limitations and unpredicted halt of the oil sand extraction pilot plant.

It is in this report given an analysis of the effect of utilizing load control in the Norwegian power system, which is one of the functions included in the Smart Grid consept. The analysis is performed by running simulations in the EMPS model. Effects are investigated in terms of increased socio-economic surplus in Norway and reduced prices during peak load periods in the area Østland.Based on earlier studies it is assumed that it is possible to disconnect 600 MW of electric water heaters during peak load hours without reducing any comfort for customers. In this analysis, 600 MW is shifted from two peak load hours to a low load period, implying that 6 GWh/week (600 MW*2h/day*5 days/week) is shifted from peak load periods to low load periods.Simulations using the existing model of the Nordic system show a net increase in socio-economic surplus of 20.208 MEUR per year by implementing a load shift. The average prices during the peak load periods are in this case reduced by 0.06 cent/kWh. In an extreme situation, a price reduction of 33.02 cent/kWh is observed. Including variation of wind power production in these simulations shows that the average price reductions are smaller and that the effect obtained in extreme situations is significantly smaller. This indicates that the effect of a load shift is somewhat smaller than what the results in the other simulations have shown.An improved system model, where the functions quadratic losses and gradual consumption adaption are included, give that a load shift increases socio-economic surplus by 41.198 MEUR per year. The average price reduction are found to be about the same as obtained by the original model. The price reductions in extreme situations are however considerably lower.Varying the exchange prices with the continental areas gives increased price differences between the price periods, which results in an even larger effect of load shift. The effect is especially large in a scenario where the prices in Germany and the Netherlands are very low during off-peak periods due to increased wind power production while the peak prices are high due to use of gas power plants instead of coal. An average peak price reduction of 0.07 cent/kWh and a price reduction of 10.48 cent/kWh during extreme situations are here found.Some uncertainty is connected to the results due to difficulties when comparing results from different simulations, which occurs when the calibrating the models. However, the results still indicate the range of the values that a load shift provides, which is clearly positive.

The hydraulic models representing hydro turbines and conduit system found instandard model libraries of power system analysis tools are often simplied mod-els. Subsequently, important information about the dynamics of the hydraulicsystem may not be properly represented by such models, putatively resultingin insucient representation of the interaction between the electric system andhydraulic system.In this master thesis three dierent hydraulic models for hydro power plantsequipped with Francis turbines for use in power system simulation software hasbeen studied: 1) a simplied model often found in power system simulation tools;2) a model including a surge tank and elastic water column and 3) a model thatincludes a surge tank, elastic water column and turbine parameters accountingfor the characteristics of the hydraulic turbine.The hydraulic models were implemented in Simpow, a power system simulationtool. A frequency scan in the range from 10􀀀3-5 Hz was performed. The re-sults were compared with a frequency scan from LVtrans, a program specicallydesigned for accurate simulation of the dynamics of the hydraulic side in hydropower plants. The comparison showed that the simplied model failed to prop-erly represent the dynamics of the conduit system. The the model with surgetank and elastic water column was able to represent the dynamics of the con-duit system with satisfactory accuracy. Best representation was achieved for themodel including turbine parameters.The three hydraulic models were implemented in three dierent power systemcongurations: a single machine innite bus system; a system consisting of twointerconnected areas; and a system that has sustained power oscillations. Theresulting active power delivered from the generator were the hydraulic modelswas implemented, the speed of the turbine, the pressure at turbine and the owthrough the turbine were investigated.The simulation results revealed that the active power variation from the gener-iiators is in the same range for all three models, except for the simulation withsustained power oscillations. The speed variations of the turbine as a result ofincidents in the electrical network are in the same range for all three models.The model including turbine parameters is the only model able to representthe pressure variation as a result of a variation of speed of the turbine. Forpower oscillations with frequencies equal to the half period frequency of the waterhammer eect,1.38Hz, both the model with surge tank and elastic water columnand the turbine parameter model show very little response. For frequencies equalto the water hammer eect, 0.69Hz the variation in ow is also small for the twomodels. In general, the model with turbine parameters are better damped thanthe two other models.Further work should include development of an automated routine for determin-ing parameters to use in the model with turbine parameters as well as investiga-tions of how the model behaves in dierent network congurations.

I denne masteroppgaven har det blitt sett på hvordan fleksibilitet i strømforbruk kan utnyttes for å bedre forsyningssikkerheten og redusere topplast. Europa står foran store utfordringer med stadig økende forbruk og økt andel uregulerbar fornybar energi, samtidig som kraftnettet blir eldre. Også i Norge har vi områder med stort energiunderskudd og begrensninger i overføringskapasitet inn til området. Det går utover forsyningssikkerheten, spesielt hvis det oppstår avbrudd og en linje faller ut av drift. Norge skal innføre avanserte måle- og styringssystemer (AMS) med målere som skal registrere forbruket minimum en gang i timen og med mulighet for registrering hvert 15. minutt. Etter forslag fra Olje- og energidepartementet og Norges vassdrags- og energidirektorat skal de nye målerne være installert i alle målepunktene i Norge innen 1.1.2017. I Midt-Norge er det foreslått nye målere i 80 % av målepunktene innen 1.1.2014. Pr. juni 2011 er ikke fristene for utrulling endelig vedtatt. De nye målerne skal gi forbrukerne motivasjon for å redusere forbruket i timer med høy pris og stor belastning på nettet. AMS kan gi mulighet for å koble ut enkelte laster, som varmtvannstanker, panelovner og varmekabler, i husholdninger i et stort område. I denne masteroppgaven fokuseres det på Midt-Norge og hvilken betydning slik utkobling av last kan ha å si for belastningen i sentralnettet. I Midt-Norge er det identifisert en fleksibel last i husholdninger på totalt 240 MW. Det er gjennomført lastflytberegninger der det er sett på virkningen av å koble ut opptil 240 MW last ved feil i en linje i sentralnettet inn til eller i Midt-Norge. Beregningene viser at i situasjoner med høyt forbruk og lav produksjon i Midt-Norge kan lastutkobling benyttes for å holde effektflyten på snittene inn mot området lavere enn overføringsgrensen. Dette er særlig aktuelt ved utfall av en linje inn mot Midt-Norge eller ved tap av produksjon i Midt-Norge. Ved å redusere topplasten kan tapene i sentral- og regionalnettet reduseres med opptil 10 MW, avhengig av hvor mye som kobles ut og last- og produksjon i Midt-Norge den aktuelle timen.

I denne masteroppgaven undersøkes det hvordan polarisasjonsfenomenet og DC ledningsevnen påvirkes av ulike faktorer. Det legges spesiell vekt på å vise hvordan temperatur, tid og spenning påvirker disse fenomenene. Resultatene av analysen brukes til å vurdere retningslinjer for dimensjonering av massekabelisolasjon.Forsøkene som ble utført for å karakterisere disse faktorene, var måling av polarisasjons- og depolarisasjonsstrømmer både på tvers og på langs av kabelenisolasjonen. Spenning og temperatur ble variert for å undersøke hvordan ledningsevnen og polarisasjonen ble endret av dette. For å kunne gjennomføre forsøkene ble det laget en målekrets og to prøveobjekter. Det første prøveobjektet var en 4,5 meter lang kabel som ble brukt til å måle den dielektriske responsen på tvers av kabelisolasjonen. Det andre prøveobjektet var en 25 mm tykk kabelskive som ble brukt til å måle den dielektriske responsen på langs av kabelisolasjonen. Disse prøveobjektene ble tatt ut av en del av NorNed kabelen. Dette er en 450 kV HVDC massekabel. For å logge målingene, ble det utviklet et eget loggerprogram som styrte hele prøvetakningen. En bit av kabel ble også dissekert for å se nærmere på kabelens oppbygning, og de ulike isolasjonsmaterialenes dimensjoner. Arbeidet med denne masteroppgaven har ledet frem til følgende konklusjoner:I kabelisolasjonen vil den mest dominerende polarisasjonsmekanismen være grenseflatepolarisasjon. Det vil likevel foregå to ulike typer grenseflatepolarisasjon, en rask grenseflatepolarisasjon i oljefilmene i isolasjonen, og en tregere grenseflatepolarisasjon i buttgapen.På bakgrunn av resultatene og diskusjonen kan en konkludere med dielektriske respons og DC ledningsevne i en massekabel er avhengig av temperatur, tid, påtrykt spenning og kabelisolasjonens oppbygning.Når det gjelder den dielektriske responsen kan en ut fra tidskonstantene for de forskjellige forsøksresultatene konkludere med at polarisasjonen i kabelisolasjonen skjer raskere ved temperatur og spenningsøkning. Polarisasjonsstrømmen vil også raskere stabilisere seg ved økning av disse parameterne. Stabiliteten til polarisasjonsstrømmen var f. eks ved t = 6 h, 35 ganger mer stabil for forsøket utført ved 60 ͦ C og 10 kV enn for forsøket utført ved 20 ͦ C og 3 kV.Ledningsevnen til kabelisolasjonen er hovedsaklig avhengig av påtrykt E-felt og temperatur, men for massekabler vil også isolasjonsoppbygningen være en avgjørende faktor. For prøveobjektet der ledningsevnen ble målt på tvers av kabelisolasjonen ble ledningsevnen beregnet til:σ=5,79*〖10〗^(-17) e^((0,105T+0,155E))Ledningsevnen på langs av kabelen kan som en forenkling sees på som ledningsevnen til oljen. Denne ble målt til å være 103 ganger høyere enn ledningsevnen på tvers av kabelen. Dette vil si at konduktiviteten vil stort sett være forårsaket av oljen i isolasjonen. Ladningene vil altså bevege seg i buttgapene og oljefilmene i kabelisolasjonen.Som en løsning på dette problemet kan buttgap og oljefilmer gjøres mindre, men det er viktig at dette ikke går utover kabelens mekaniske egneskaper. Siden ledningsevnen er avhengig av temperaturen, og ledertap vil føre til varmeutvikling, er det også viktig at den termiske konduktiviteten i isolasjonen er god. Hvis temperaturvariasjonene i kabelisolasjonen er stor vil dette føre til en skjev feltfordeling. Bedre kontroll i produksjonen av hvor brede buttgapene i isolasjonen faktisk lages, og hvor stor variasjon bredden til buttagene blir, vil også bedre kabelens egenskaper. Hvis bredden på buttgapene varierer mye kan det oppstå "weak spots" i isolasjonen. Det er også mulig å eksperimentere med ulike dimensjoner på papirstrimlene i isolasjonen for å prøve og bedre isolasjonens elektriske egenskaper.

This paper describes a proposed test plan for harvesting energy from waves with a linear machine that uses gas-springs. The linear machine “Prototype 2B” has been put into production and will be finished. The machine has been constructed to withstand 300 bars of gas pressure and the maximum speed of the rotor is set to 10 m/s due to the sealing. The model made in [5] uses the fundamental equations and describes the system behavior of a linear machine with gas springs. The model has been slightly improved and the input specifications for the “Prototype 2B” have been used. The simulations shows that one needs to feed electric energy in some parts of the cycle, but the whole cycle will yield a positive net contribution of electrical energy. The model is not optimized, and hence should be improved due to the time consuming simulations. Steel profiles have been proposed to use for the frame of the test-bench. The first draft of the drawing has been sent to NTNU and the workers have started to build the frame. To ensure the vibration energy to spread itself into the surroundings, isolators need to be selected and adapted. The natural frequency of the test bench with four chosen isolators was calculated to 18,17Hz. The chosen isolators are therefore most likely good enough since the lowest operating frequency of the machine was simulated to 55 Hz.Transferring the energy from the high-force-low-speed source (the wave) to the resonator has been discussed and some suggestions have been proposed. The energy transfer is done by raising pressure in a freestanding actuator with a hose connected to the gas spring. Hence, increasing the actuator pressure will increase the gas spring pressure and the force acting on the rotor will be significantly higher. A procedure to select the correct components are discussed and a Matlab script for analyzing the choice has been made. The high-force-low-speed source has been discussed. Two solutions where a hydraulic system is used have been further investigated, and some calculations and analysis have been performed. Simulations show that one need to apply a maximum force of 24115N at one actuator with a 32mm effective piston area. The regulation of the high-force-low-speed source could be crucial to obtain a good test result since the regulation of the wave must adapt itself to the resonating force of the rotor. The regulation must therefore be investigated further as it can have tremendous impact on the possibility of extracting energy from the machine.The electrical source and regulation control have been discussed. Timing of the electrical energy supplied is crucial and three operational simulations have been performed to investigate when the positive net contribution is at it`s highest. In order to extract the maximum possible net energy from the machine, the right electrical control is very important to implement. Two of the control systems have been proposed, where perhaps the simple proportional controller should be chosen to prove the concept. Later on a more sophisticated electrical controller should be applied since the efficiency of the wave energy converter could increase significantly.The non-linear compression event in the gas-springs is not proportional to the electrical extracted energy. Simulations show that when the pressure increases in the springs one could extract more energy, but the non-linear event could not be recognized. Simulations show that the efficiency of the system varies significantly with the controlling of the machine. If a simple proportional controller is adapted, the theoretical efficiency becomes 2,87% and with a more sophisticated controller one could get 10,02%. This means that there must be done more research on the electrical operating control system if energy harvesting could be profitable.

AbstractIn relation to new building directives and regulations there is much focus on energy efficiencyand reducing the use of electricity. There is therefore a need for ventilation systems with lowSpecific fan power (SFP) and to limit or avoid the need for mechanical cooling.At the same time questions are raised concerning whether increasingly complicatedventilation systems are the best way to achieve energy efficiency. They are more vulnerablefor poor design and maintenance which especially school buildings have suffered from.This has led to the development of several natural and hybrid ventilation concepts. One ofthese which has had success in school buildings the last 15 years in Sweden and Norway isthe so-called Swedish model. Characteristic of this solution is that sub terrain culverts areused for passive cooling and heating of the ventilation air which passes through double innerwalls and is supplied to the room high on the inner wall. The supply air falls towards the floormixing in the surrounding air and spreads along the floor as displacement flow with an outletin the ceiling. This works particularly well in classrooms where the high occupation densitycreates a cooling demand large parts of the year. These schools therefore have a very low SFPfactor and no mechanical cooling.In the following report a classroom model with the Swedish ventilation concept is studiedwith the aim of developing a method of dimensioning such air flow. CFD simulations areused to confirm expected behaviour and the resulting thermal comfort and air quality attypical winter, spring and summer scenarios. Finally a Guide for preliminary design andsizing for climatization of rooms with cooling needs using the Swedish model is presented.The most important results were that there was a good correspondence between the empiricalcalculations and CFD simulations. Adequate carbon dioxide levels and temperature can beachieved without use of primary energy for heating at for outdoor temperatures above 5 ºC.There was a substantial risk of draft unless a near zone of 2-3 m is used. However the CFDmodel was limited to a slice of the classroom and the accuracy of the results suffers somewhatfrom this.Guidelines are developed for preliminary design and sizing of supply air plumes based onempirical expressions of air flow by Eimund Skåret(2000) and can be found in the appendix.

LCA of buildings has become a distinguished field of LCA, and a number of previous studies have found that low energy buildings generally have better life cycle performance than conventional buildings. However, there has been a lack of studies comparing low energy buildings against passive buildings. The present study evaluates life cycle performance of two passive and two low energy buildings that are all part of the housing cooperative Løvåshagen in Bergen. Construction of the housing cooperative was completed in 2009 and measured material and operational data was used in a comprehensive LCA of the whole life cycle from cradle to grave, for twelve midpoint impact categories. The functional unit is a lifetime of fifty years of one square meter BRA of a building block apartment. Heating for low energy apartments are provided by electric resistance heaters and heating cables in the bathroom floors, while hot water heating is provided by an electric water heater. Evacuated tube thermal collectors are located on the roofs and provide passive house room heating through hydronic radiators and hydronic floor heating. They also provide hot water heating for each apartment. When solar collector output is not sufficient, heating is supplied by electric resistance elements.The LCA results show practically no difference between the climate change performances of the house models, and this is largely the result of a particularly low passive house performance. In simulation-based LCA literature there appears to be a trend of over-estimating the operational performance of passive and low energy buildings, and Løvåshagen is no exception. The measured electricity consumption is high, both compared to estimations and to the results of other, simulation-based, studies. The high consumption appears to be a result of a particularly low outdoor temperature for the year of the measured data. It is recommended to monitor the electricity consumption over the next few years of operation, and if it is not significantly reduced there is reason to suspect faults in building construction or in the solar collector system. In the case of no direct defects there is reason to re-evaluate the effectiveness of solar collectors for the climatic conditions of Bergen.

A dynamic one-dimensional homogeneous model for a packed bed sorption-enhanced water-gas shift (SEWGS) reactor has been developed, describing the non-isothermal, non-adiabatic and non-isobaric operation of this type of reactor. The model was developed to describe a SEWGS reactor designed to work under operating conditions and syngas feeds encountered in a coal-fed Integrated Gasification Combined Cycle power plant utilizing an oxygen-fed gasifier. Different from previous integration designs reported in literature, the feasibility of leaving out the conventional high-temperature water-gas shift (WGS) reactor upstream of the SEWGS reactor has been investigated. The reactor was assumed to be packed with a mixture of K2CO3-promoted hydrotalcite CO2 adsorbent and commercial high-temperature FeCr-based water-gas shift catalyst pellets. Utilizing the reactor model, a mathematical modelling framework for the operation of eight SEWGS reactors in a SEWGS cycle has been developed. This system model accounts for all the necessary interactions between the reactors during the SEWGS cycle, including the exchange of mass in the feed, rinse, equalization and repressurization steps. In contrast to available open literature, the mathematical framework describes in detail how the necessary switches in the boundary conditions for the reactors have been realized.Simulations of several SEWGS cycles were carried out. The results were compared with experimental and modelling data from literature. Due to inconsistencies in the parameters and implementation of the model in the simulation software employed, results were in most aspects quantitatively not comparable to results from literature. However, the qualitative trends and physical mechanisms expected were observed and confirmed by the model. The temperatures in the reactors reached an unacceptable high level with respect to the tolerable operating conditions of the catalyst and adsorbent. It is planned to continue the work on the model, and implementing it within a full power plant model to investigate the effects of changes in the power production and thus the required amount of syngas to be treated.