Mål Simulere Svartisen Kraftverk i LVTrans og sammenligne med frekvensresponsmålinger. Oppgaven skal bearbeides utifra følgende punkter: 1) Kandidaten skal sette seg in i teorien bak og metoder for frekvens respons målinger 2) Kandidaten skal delta i planlegging og utføring av målinger 3) Analysere data fra målingene 4) Modellere kraftverket i LVTrans 5) Utføre transiente simuleringer 6) Sammenligne resultat fra målinger og simuleringer, og identifisere og begrunne eventuelle avvik

Vannkraftlaboratoriet har i den siste tiden opplevd stor pågang fra eksterne firmaer som ønsker å teste modeller av turbiner og andre vannkraftmaskiner. Det er derfor ønskelig å kartlegge kapasiteten til pumpene i Vannkraftlaboratoriet. I denne oppgaven er det utført målinger av pumpene. På grunnlag av målingene er det utarbeidet en pumpekarakteristikk med virkningsgradskurver. Pumpene, to KSB 400-665, ble kjørt i singel-, serie- og parallelldrift, og det ble utarbeidet pumpekarakteristikker for disse konfigurasjonene. Det ble ved undersøkelser funnet at pumpekarakteristikken er stabil i alle områder. Det ble utført trykkpulsasjonsmålinger på pumpene og i rørsystemet for å se i hvor stor grad trykkpulsasjoner fra pumpene kan påvirke turbinforsøk. Av den grunn er pumpene kjørt i system med en høytrykks-Francis modellturbin. Pumpas løpehjulsfrekvens (turtallsfrekvens) og harmonier, samt løpeskovlfrekvens ble identifisert i trykkpulsasjonsmålingene på pumpa. Disse frekvensene dempes ut i systemet. Trykkpulsasjonsmålinger på turbinmodellens innløp viste en reduksjon av løpehjulsfrekvensen, mens harmonifrekvenser og løpeskovlfrekvensen elimineres. På grunnlag av disse observasjonene kan det slås fast at turbinforsøk ikke påvirkes av trykkpulsasjoner generert i pumpa.

CO2 is an environmentally friendly refrigerant that has a no global warming potential when used as refrigerant. The current refrigerants used for air conditioning in public transport are chemical components, and have a high global warming impact. The possibility of replacing the conventional refrigerants by CO2 is investigated for various parts of the transport sector. A possible CO2system for heating and cooling for public transport has been modeled and simulated. This system is a turntable prototype which is reversing the airflows to provide either cooling or heating. It has two gascoolers and two evaporators for separate treatment of ambient and recycled air. The plate is rotated 180˚ to switch from heating to cooling mode. CO2 has large potential for expansion work, due to the normally large throttling losses for high ambient temperatures. An ejector has therefore been implemented in the heat pump circuit. The turntable prototype is modeled by the simulation tool Modelica, and it is investigated how this ejector system adjusts to varying ambient conditions and power demand. Weather data from the climate database Meteonorm was used as a basis for calculation of heating and cooling demand for a train compartment in five different cities, covering a variety of climates. A case study was performed based on an occupancy rate profile and operative hours of the heat pump for the compartment. Simulations were performed of the air reversing heat pump based on the heating -and cooling demand calculations for the five cities. The COP values obtained are very positive, and they are in general higher for heating than cooling mode. The COP is depending on the load, and decreases with reduced occupancy rate. For cooling mode the COP ranged from 3.1 to 6. For heating mode it ranged from 8.2 to 2.8. With the occupancy rate chosen, the annual energy savings is about 80% for all the 5 cities of the study. The fan work of the heat pumps was also included for 4 different operating modes. This reduced the total COP by between 10 to 40%, depending on heating and cooling power requirement and ambient conditions. The fin and tube gas coolers that were used in the Modelica model were compared to a set of MPE gas coolers. The total mass of the heat exchangers was reduced by 50%. One would still have to weigh the reduced mass and increased LCCP performance against the increased investment cost of the MPE heat exchangers.

SINTEF and NTNU are planning to build a 150 kWth Chemical Looping Combustion (CLC) reactor system. This is new technology and the CLC reactor system is going to be one of the largest of its kind in the world. The technology is promising for CO2 capture in terms of energy efficiency and economics. To verify the design a Cold Flow Model, CFM, has been built. In the CFM no reactions take place, but it simulates the hydrodynamics of the 150 kWth CLC reactor system. The reactor system consists of two reactors exchanging solids in a loop. The two reactors are one air reactor, AR, and one fuel reactor, FR. Air is injected at different locations in the CFM to fluidize the solids and achieve the proper mass flows. The Cold Flow Model has been commissioned and an experimental campaign was executed. A series of experiments running each reactor singularly were performed. The rig seems to be functioning satisfactory and a minimum of plugging in the pipes were observed. The Cold Flow model has two cyclones that showed collection efficiencies at approximately 99 %. This is important to avoid emissions of solids from the future CLC reactor system, both for economic and environmental reasons. An investigation and mapping of the operating area of the reactors singularly and coupled was the target of the experiments. Correlations between operating velocity, total solid inventory, air distribution and flux were found. Appropriate flow regimes, meant to give good gas solid contact efficiency, and mass flow’s entrainments were achieved. The targets of a solid circulation rate of 2 kg/s in the AR and 1 kg/s in the FR were also achieved. Air is injected in the bottom of the reactors to fluidize the particles. This air is distributed through primary and secondary nozzles. The highest primary air percentage tested in the FR, 75%, gave the highest flux. In the AR 100% was tested, but 70% gave the highest flux. The last result is in contradiction with other experimental work in the area which says that 100% primary air should give the highest flux. After the mapping of the operating area of the single reactors it was possible to try to run the two reactors coupled. The divided loop seal was tested but led to a pressure short circuit and a large amount of the total solid inventory was lost out of the cyclones in a short time. The operation of a divided loop seal is probably possible, but seems difficult. The internal part of the loop seals were sealed to make the operation easier. The loop seals could then be operated as traditional loop seals. A challenge was the mass balance between the fuel reactor and air reactor. The mass flows of particles from both reactors must be equal to have a mass balance. Otherwise all the particles eventually ends up in one reactor. Results from the single reactor experiments were used to know approximately which operating conditions gave a mass balance between the reactors. The Cold Flow Model seemed to a certain degree be self regulating for achieving a mass balance if initial operating conditions were reasonable. Two experiments with coupled reactors and mass exchange only through the loop seals were done. A global solid circulation rate of 0.7 kg/s and 1 kg/s was achieved. Both AR and FR had the proper flow regimes. Proper flow regimes in the reactors are turbulent or fast fluidization. A third experiment utilized a lifter to enhance the solid transport between the reactors. A lifter is a additional transporter of solids from one reactor to another. The lifter worked successfully. The experiment had a global solid circulation rate of 1.4 kg/s. The mass flows were 1.4 kg/s from the AR loop seal and 1 kg/s from the FR loop seal. The remaining part 0.4 kg/s from the FR to the AR was transported with the lifter. Both reactors had proper flow regimes. A fourth experiment trying to achieve a global solid circulation rate of 2 kg/s failed. The bottleneck seems to be the AR loop seal. Solids accumulated and the loop seal was not able to handle this rate of solid flow. A new operation philosophy and design of the loop seal has been proposed. The new design of the loop seal and operation philosophy reduces the air flow needed in the loop seal, but it may not necessarily solve the solid circulation limit in the AR loop seal. Further investigation is needed. Manipulating the pressure in the AR may contribute to enhance the rate of solid flow through the loop seal. The successful experiments were presented at the 1st International Conference on Chemical Looping, IFP-Lyon, France, 17 - 19 March 2010. After the experimental campaign was finished the experiments were simulated with the fluidization software ERGUN developed by Compiegne University of Technology. ERGUN applies different mathematical models. For the simulations performed Horio’s and Berruti’s model were applied. The evaluation of the ERGUN simulations by means of the experiments shows that Horio’s and Berruti’s model should not be used for a detailed investigation of the flow structure in the CFM’s risers. However, despite its strongly empirical nature, a preliminary investigation of the riser’s behavior with Berruti’s model may be useful. Berruti’s model is a reasonable tool for modeling the upper part of the pressure profile in the AR and FR at the operating conditions tested. The operating conditions tested in the AR are total solid inventories of 35 and 45 kg, and superficial gas velocities from 0.9-1.9 m/s. The operating conditions tested in the FR are total solid inventories of 35 and 50 kg, and superficial gas velocities from 1.5-2.0 m/s. Berruti’s model is not capable of accounting for the dense bed in the lower part of the reactor as Horio’s model does. However, Horio’s model mismatched the experimental results too much. Horio’s model seems to be a provide a better match at larger total solid inventory and smaller operating velocities, hence flow regimes not relevant for the CLC reactor system.

The task of this project was to investigate the near wake, performance characteristics and yaw moment on a model wind turbine. The test turbine is a horizontal axis three bladed machine with a rotor diameter of 0.9 meter. Initially it is an upwind turbine, but was used for downwind measurements as well by rotating the blades and the entire construction 180^0. For the wake measurements the tip speed ratio was set to be TSR=3, TSR=6 and TSR=9 to describe the different regimes; partly stalled, optimal operation and partly propeller operation. Two different yaw angles, 0^0 and 30^0, was also explored for the near wake measurements. The velocity field was measured at X/D=1, as well as X/D=4 for TSR=6 and the two yaw angles; X/D being the number of rotor diameters downstream from the rotor plane. The performance characteristics and yaw moment were measured for yaw angles 0^0, 10^0, 20^0 and 30^0, and with tip speed ratios from 1 to 11. The power and thrust coefficients were found to decrease with increasing yaw angle. This is due to the reduced projected rotor area and reduced effective wind velocity component interacting with the turbine blades. The loss in power due to the yaw angle of the turbine is approximately 6% for yawAngle=10^0 and 40% for yawAngle=30^0 with upstream configuration. For downstream setup the reduction in power due to the yaw angle was 5.2% and 38% for yawAngle=10^0 and yawAngle=30^0 respectively. The near wake velocity field was strongly influenced by tip speed ratio and yaw angle. At TSR=3 the outer parts of the wake had a velocity close to the freestream velocity. Therefore much of the flow passes through without interacting with the rotor blades. For TSR=6 the velocity deficit was close to uniform in the wake. Most of the turbine blades operate efficiently at the design condition, and gives the peak in the power coefficient curve at this TSR. When TSR=9 the inner part of the blades experience negative angle of attack and provide energy to the wind instead of subtracting it. The outer parts of the blade operate more efficiently, but due to the inner part working as a propeller the power coefficient is low. The thrust coefficient is high for this operating condition. When the turbine is operating in yawed condition, the wake width is reduced and shifted towards the yawed direction. At downstream distance X/D=4 for TSR=6 the wake deficit becomes more uniform for both yawAngle=0^0 and yawAngle=30^0. For the downstream configuration the yaw moment was generally stable at more operating conditions than the upstream setup. Common for both configurations was that the yaw moment tended to rotate the rotor plane out of the wind at low tip speed ratios and yaw angles. The downwind turbine got a stabilizing moment for a lower tip speed ratio than the upwind turbine for all yaw angles. Both upwind and downwind turbine setup had an unconditionally stable yaw moment for yawAngle=30^0.

An integrated approach to climate and energy policy is required to meet the challenges associated with climate changes caused by anthropogenic emissions. At the same time, the demand for electricity is increasing. Wind power is considered as part of the solution in solving these challenges, as this is renewable energy. By relocating wind power production offshore, stronger winds are achieved that increases electricity production without having emissions of GHG during power production. Europe's ambitious goals and plans for development of offshore wind power development in the North Sea have also raised questions about how to integrate wind power into existing power systems in Europe. In this study the environmental impacts of offshore wind power production and development of an offshore grid in the North Sea, have been considered. To quantify the environmental impacts associated with offshore wind power generation and power transmission in the North Sea, several LCA’s have been carried out. Four LCA's were conducted, whereof three of them were analyses of various submarine cables used either in offshore wind farms or long-distance power transmission. The cables studied were; 33 kV HVAC cables used internally in offshore wind farms, 132 kV HVAC cables used to transmit power from a wind farm to the grid onshore and 450 kV HVDC cables used for long-distance power transmission between for instance countries. A fourth LCA was conducted of an entire offshore wind farm, including the inventories of the 33 kV and 132 kV cables. The emissions from a 390 MW offshore wind farm with bottom-fixed windmills, were calculated to be 20.6 g CO2 -equivalents/kWhel. Cabling constituted only 1.5 % of the total impacts to climate change from the wind farm. A larger wind farm of 9000 MW had lower estimated emissions of 19.8 g CO2 -equivalents/kWhel due to a higher electricity production. The LCA results of the 450 kV cables were used in estimating the environmental impact caused by different designs of offshore power grids in the North Sea. Several alternative grids were investigated, both with and without wind farms. For instance, a power grid in the North Sea where the two wind farms above were implemented, had estimated emissions of 84 million tonnes of CO2-equivalents throughout lifetime. This represents approximately 2% of the EU-27 countries' total GHG emissions from 2007. In addition to the quantification of environmental impacts, a qualitative discussion was conducted of the various environmental costs and benefits associated with large-scale development of power generation and transmission in the North Sea. The results from this study indicate that the expected environmental impacts from developing offshore wind farms and power grids in the North Sea are not insignificant. The positive environmental effects are large because the increased transmission capacity between power markets allows for increased development of electricity generation from intermittent renewable energy sources like wind power. Increased share of renewable energy reduces the need for power generation from fossil fuels, thus there will be an environmental gain. The study seeks to emphasize the complexity and the important aspects of the assessment of environmental impacts associated with large power systems.

In this study the environmental costs and benefits of smart metering technology systems installed in households in Norway have been assessed. Smart metering technology systems enable mechanisms to manage electricity consumption by shifting loads. With the use of Life Cycle Assessment (LCA) and the ReCiPe method for impact assessment, the life cycle impacts of installation and operation of a system in a household have been found. Environmental benefits of using the systems to manage electricity consumption have been quantified. The results of the study indicated that the environmental costs of smart metering technology systems mainly are caused by the production of system components and system electricity use during operation. For the production of system components, the use of electronics in the components was generally the major contributor to the total environmental impacts. Further, the systems metal depletion potential was high relative to other environmental impacts after normalization in impact assessment. The main environmental benefits of smart metering technology systems in a Norwegian perspective will be in a critical supply situation of electricity to avoid use of reserve capacity gas power plants, and the results from the study showed that the systems in such a case can contribute to an avoided emission of greenhouse gases. Load shifting from a general basis may however not always have environmental benefits and this will depend on the existing alternatives for electricity production.

19. mai ble det utført virkningsgradsm°alinger av Norconsult AS ved Nore I Kraftverk i Buskerud. På denne målingen var Stud. Techn. Arild Høydal medvirkende, og utførte samtidig egne målinger av energifordelingen i avløpet til bruk i masteroppgaven. Kraftverket består av åtte Peltonturbiner, hver på 26 MW, og har en fallhøyde på 343 m. Målingene ble utført på turbin 8, som nettopp ble satt i drift etter utskifting av løpehjulet. En garantiåaling av virkningsgraden skulle derfor utføres. Denne oppgaven består av to hovedmål. Det første er å sette seg inn i teorien bak termodynamiske virkningsgradsmålinger for å deretter være med på måling og utføre beregninger på virkningsgrad og usikkerhet basert på måledata. Det andre målet er å gjøre detaljerte målinger av både temperatur- og hastighetsfordeling i avløpet på kraftverket. Dette er for å se om kunnskaper om energifordelingen gjør at man kan få ned usikkerheten i målingene. Da vil det også være mulig å sammenligne den målte usikkerheten med usikkerheten man er anbefalt å sette på energifordelingen i avløpet. Målingen av virkningsgraden var vellykket med gode måleforhold og små forstyrrelser. Målingen av energifordelingen var bare delvis suksessfull, ettersom hastighetsmålingene ble vurdert til å være ugyldige. Dette var likevel et mindre problem, ettersom temperaturvariasjonene på tvers av avløpet ble funnet til å være rundt 1 mK. Dette gjorde at virkningsgraden varierte lite fra kontrollflate til kontrollflate, og en hastighetsvekting av kontrollflatene gav lite utslag. Måleusikkerheten ble funnet til å være 0.76% relativt til virkningsgraden for alle lastpunktene, som er en akseptabel usikkerhet for en virkningsgradsmåling. Denne usikkerheten ble derimot redusert til 0.47% når det ble brukt usikkerheter på energifordelingen i avløpet i stedet for anbefalte verdier fra IEC 41. Det demonstrerer fordelen av å kartlegge energifordelingen i avløpet. På bakgrunn av målingene utført ved Nore I og tidligere målinger på andre Francis- og Peltonturbiner, ble det konkludert med at usikkerheten på 0.60% for Em blir unødvendig høy for kraftverk med stor fallhøyde. Denne oppgaven støtter tidligere forslag om å heller sette en absolutt usikkerhet på 2 mK på temperaturen i avløpet, som er mer representativt for observerte forhold. Et forslag blir også fremmet om å skille mellom Francis og Pelton i IEC 41 når usikkerheten skal settes på energifordelingen i avløpet, observert data antyder en større energispredning i Francissugerør enn i Peltonavløp. Flere energikartlegging av avløp trengs for å avgjøre om det er riktig.

Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was to study liquid film flow in a diverging test-channel. The channel was designed to resemble conditions found over an airfoil or diffuser in a compressor, with emphasis on study the separation of the gas boundary layer over the thin liquid film. Boundary layer separation is closely connected to instabilities (surge) in compressors and is an important aspect to shed light on. Tools used were the CFD-software Ansys CFX 13.0. CFX was validated against experimental work were high speed camera was used in terms of flow visualization. In addition, two dynamic pressure sensors were used in the channel with the subsequent FFT-analysis, to study the influence of thin liquid films in a compression process, also related to instabilities. The CFD software has proven to give promising results on multiphase flows. From the CFD-simulations it was found a significant decrease in the shear stress in the gas phase over the liquid film, compared to air over a solid, smooth surface. This finding implies that the liquid film induces an increase in frictional losses for the gas phase, which leads to increased susceptibility for the gas phase to separate. The gas phase was, however, not found to separate with the given conditions. Visual similarities to the CFD-simulations were found from the high speed camera recordings. It was observed a clear void on the profile section with a substantial decrease in velocity, which can be related to boundary layer separation. These observations are supported by the smooth liquid film structure in this region. The FFT analysis shows a decrease in amplitude on the frequency spectra when increasing the liquid mass flow.

Energibruk i supermarkeder er blant de høyeste innefor bygningssektoren i Norge. Norske supermarkeder har typisk et årlig energibehov på mellom 400 og 600 kWh/m^2 . Opp mot 50 % av dette totale energibehovet går til kuldeanlegg for kjøling og frysing av produkter for salg, både til fremvisning og lagring. Samtidig stilles høye krav til ventilasjon og belysning i butikkarealene. Energisystemer i supermarkeder opererer etter strenge krav og kriterier, som ofte er motstridende for kunder og matvarer, når det kommer til temperaturer og luftstrømning. Nye og energieffektive energisystemer for å tilfredsstille både kulde- og varmebehov i supermarkeder kan derfor bidra til å redusere energiforbruket i denne delen av bygningssektoren. Hovedmålet i denne oppgaven er å utføre transiente simuleringer for fullskala kuldeanlegg i supermarkeder, der CO2 benyttes som eneste kuldemedium. Det ble først gjort en litteraturstudie, der ulike systemløsninger for kuldeanlegg i supermarkeder ble vurdert med hensyn på energieffektivitet ved bruk i ulike klima. Et utvalg endringer/utbedringer som kan bidra til økt energieffektivitet for de ulike systemløsningene er vist, og effekten av disse utberingene er vurdert med tanke på COP og kjølekapasitet. Potensialet for bruka av varmegjenvinning fra kuldeanlegg for å dekke oppvarmingsbehov i supermarkeder er presentert, og ulike systemløsninger for bruk av varmegjenvinning er vist. Det er utført transiente simuleringer for tre ulike systemløsninger: 1. Booster-løsning med bypass av flashgass i høytrykkskrets 2. Booster-løsning med parallell kompresjon av flashgass i høytrykkskrets 3. Booster-løsning med bypass av flashgass og bruk av varmegjenvinning fra gasskjøler/kondensator Temperaturdata for europeiske byer er benyttet i de transiente simuleringene. De fire byene er Trondheim, Athen, Moskva og Frankfurt. Det ble gjort simuleringer av perioder på et døgn for de tre systemløsningene, der de døgn med lavest og de døgn med høyest gjennomsnittstemperatur gjennom et år for de fire byene. For å sammenligne energieffektiviteten for de ulike systemløsningene, er det lagt vekt på det totale energibehovet for de ulike døgnsimuleringene. I dette totale energibehovet er energibehov til kompressorer, energibehov til vifte for varmeavgivelse fra gasskjøler/kondensator til omgivelsene og energibehov til oppvarming av ventilasjonsluft inkludert. I de simuleringer der varmegjenvinning ikke benyttes, er elektrisk oppvarming antatt. Resultatene fra simuleringene viste at i de døgn med lav omgivelsestemperatur var det systemløsningen der varmegjenvinning benyttes som resulterte i det laveste energibehovet. For simuleringene med høy omgivelsestemperatur, var det systemløsningen med parallell kompresjon av flashgass som viste det lavest energibehovet, for all de fire byene. Basert på resultatene fra døgnsimuleringene ble årlig energibehov for de tre systemløsningene beregnet for de fire ulike byene. Beregningene viste at systemløsning 3, der varmegjenvinning benyttes, resulterte i lavest årlig energibehov for alle de fire byene. For byene Trondheim, Athen, Moskva og Frankfurt kunne en se en reduksjon i totalt energibehov fra systemløsning 1 til systemløsning 3 på henholdsvis 40 %, 7 %, 36 % og 25 %. Andelen av det totale oppvarmingsbehovet som ble dekket ved varmegjenvinning for systemløsning 3 var da på henholdsvis 85 %, 35 %, 83 % og 71 %. For alle fire byene resulterte systemløsning 2 i en reduksjon i årlig energi behov i forhold til systemløsning 1 på mellom 3,6 % og 5,3 %, og reduksjonen var høyest, der omgivelsestemperaturen var høy i store deler av året. Resultatene fra simuleringene viser høy energieffektivitet for systemløsning 3, der varmegjenvinning benyttes. Ulike faktorer tilsier at forskjellen i totalt energibehov mellom systemløsning 3 og systemløsning 1 og 2 ikke vil være like stor, som det resultatene presentert her viser. Reguleringskurvene for optimalt gasskjøletrykk ved transkritisk drift av modellene viste seg å ikke være nøyaktig nok. Dette medfører et økt energibehov til viftedrift for å oppnå nødvendig nedkjøling av gasskjøleren. Dette kombinert med at gasskjøleren/kondensatoren ikke er detaljmodellert for bruk i de ulike byene, og en økning i luftmengden fra viften resulterer i en stor økning i trykkfall over luftsiden av gasskjøleren, kan være med å bidra til et for stort energibehov til viftedrift i de simuleringene der omgivelsestemperaturene er høye. Totalt sett gir simuleringene og beregningene gjort her viser at potensialet for reduksjon i årlig energibehov for supermarkeder ved bruk av varmegjenvinning er betydelig ved bruk på steder med forholdsvis kjølig klima.