Hensikten med denne studien har vært å kartlegge mulighetene for å etablere en superkjølt produksjonslinje for svinekjøtt på et slakteri. For å kunne vurdere mulighetene for å utnytte eksisterende kuldeanlegg, ble det gjennomført målinger i den eksisterende slakterilinja. Produkttemperaturer ble målt gjennom hele kuldekjeden, fra slakting til distribusjonslager. Energibruken i enkelte kuldeanlegg ble også målt. For superkjølingsprosessen ble det også vurdert å installere en skallfryser. Kjøletiden i skallfryseren ble estimert ved hjelp av FVM (finite volume method). Temperaturmålingene viste at et eksisterende kjølerom kun kunne benyttes i en småskala superkjølingslinje. Rommet brukes i dag til kjøling av stykker av nakke og svinekam, slik at disse er delvis fryst når de blir hakket opp til koteletter. For å kunne senke temperaturen til superkjølingsnivå, må produktene oppbevares på kjølerommet over natten, og kapasiteten er derfor begrenset av hvor store mengder det er plass til i rommet. Siden den daglige produksjonen av koteletter er nok til å fylle rommet, vil en eventuell superkjølingslinje være begrenset til produktene som kjøles i dette rommet i dag, eller en tilsvarende mengde av andre produkter. Med lang kjøletid kan man også forvente økt vekttap fra produktet. For å kunne superkjøle større mengder, og få kortere kjøletid, bør man installere en skallfryser. Denne kan plasseres i det eksisterende kjølerommet. Med skallfryser kan produktet kjøles ned til ønsket entalpinivå i løpet av kort tid, og den videre prosesseringen kan skje samme dag som nedskjæring. Små endringer i produktstørrelse, innløpstemperatur, varmeovergangstall eller lufttemperatur, gir betydelig utslag i den estimerte kjøletiden. Siden simuleringen ble gjennomført med estimater for disse verdiene, kan man ikke forvente å finne riktig kjøletiden med denne metoden. Den faktiske kjøletiden må bestemmes eksperimentelt for det konkrete tilfellet som gjelder på slakteriet. Selv om estimatene ikke kan brukes til å bestemme den korrekte kjøletiden, gir de forståelse for forholdene som påvirker kjøletiden i skallfryseren. Siden produkttykkelsen varierer, både for det enkelte produkt og mellom produktene, vil samme kjøletid gi forskjellig isfraksjon for hvert enkelt stykke. Koteletter fra den samme nakken vil ha forskjellig isfraksjon før utligning. Konsekvensene dette har for kvaliteten til det enkelte produkt, og temperaturreguleringen under lagring, bør studeres nøyere. Temperaturmålingene på kjølelageret for ferdige produkter viste for stor variasjon til å være egnet for superkjølt lagring. For å opprettholde holdbarhet og kvalitet, bør superkjølte produkter lagres ved stabil temperatur. Lagringstemperaturen for superkjølte produkter vil heller ikke passe med lagringstemperaturen for konvensjonelt kjølte produkter. Man bør derfor bygge et mindre lager for superkjølte produkter inne i det store kjølelageret. Det superkjølte lageret bør ha et eget kuldeanlegg, slik at det temperatur og ytelse kan reguleres uavhengig av det omgivende kjølelageret. Dersom man velger å installere en skallfryser, kan kuldeanlegget som i dag leverer kjøling til før hugging benyttes. Størrelsen på det superkjølte lageret avhenger av mengden produkter tiltenkt superkjølt lagring. Siden de ulike produktene har forskjellig sammensetning, vil de også ha forskjellig isfraksjon ved den samme lagringstemperaturen. Temperaturen på det superkjølte lageret må derfor velges slik at holdbarheten og kvaliteten til alle produktene sikres. På bakgrunn av estimert isfraksjon ved ulike temperaturer anbefales en lagertemperatur mellom på -1,15 og -1,10 °C, avhengig av hvilke produkter man ønsker å lagre.

A widespread use of liquid liquid separators are taking place in many industrial processes, especially in production of hydrocarbons. The separators in oil production are used to separate water from oil, increasing the purity of petroleum and making cleaner produced water in order to meet quality and environmental standards. To improve the performance of the separators it is important to understand the complex dynamics taking place. The scope of this work has been to develop and build a facility for accurately studying coalescence and coalescence time which is a key parameter in separator dimensioning, the facility is designed for droplets ranging from 50 $mu m$ to 1000 $mu m$. The relationship of droplet size and coalescence time is especially interesting. Theory on droplet formation, behavior and coalescence mechanism are introduced and a special focus is put on generation of the smallest droplets. Earlier work in this field of study is presented in the background and literature study part. It covers a brief introduction to separator design, coalescence modeling by using basic principles as gravity and surface tension and generation of small droplets by deforming a meniscus with electrostatic forces. The facility has been developed by step-wise treating obstacles and requirements. Facility development is organized by the various parts and includes droplet generation, illumination, visualization and automation of the experiments. Unfortunately a high voltage amplifier malfunctioned due to a factory error and the generation of the smallest droplets was not demonstrated. The facility is successfully build and can generate, visualize and capture the coalescence for large droplets and is ready to accept smaller ones when the high voltage amplifier is repaired. While major parts of the facility is completed there is potential for improvement by further work. Besides from demonstrating the generation of the smallest droplets it should be aimed to complete the automation of the facility and to complete the post processing by deciding a decision criteria for coalescence time. In this way a fully automated facility producing and recording hundreds of droplets of a given size can be made, making it possible to do statistical evaluation of the relationship of droplet size and coalescence time.

A synthetic jet is a flow control device which injects a pulsating jet flow of high-momentum fluid into a boundary layer near the wall confining a main flow. The technique is used to prevent or delay boundary layer separation. While the method is well reported for gas flows, less knowledge is available for liquid flows. It has been suggested that synthetic jets might be used in hydro turbines in order to stabilise draft tube flow. When accelerating a liquid flow, the energy consumption required will not only depend on the system mass, but also on the added mass due to acceleration of the liquid. The purpose of this thesis has been to study the physics of a synthetic jet where water is the working fluid, drawing special attention to added mass. CFD simulations have been conducted, where the synthetic jet was modelled using a dynamic grid. Results for added mass and frequency response of the system from CFD analysis have been compared to an analytic solution. CFD simulations seem to have captured a number of interesting effects not predicted from the analytic solution; the most prominent being frequency regions of lower added mass than analytically predicted. The apparent resonance regions are believed to occur due to interaction between the excitation frequency of the synthetic jet, and frequencies of dynamics in the system - examples are pressure pulsations from vortex shedding frequencies, or from frequencies originating from the effect of flow across a cavity. Furthermore, it has been demonstrated that operating the system at resonance will reduce the power requirements of the driving force, and that a variable stiffness spring should be part of the actuation system to allow for tuning of the resonance frequency.

A Cartesian grid method has been developed for solving the 2D Euler and Navier-Stokes equations for viscous and inviscid compressible flow, respectively. Both steady and unsteady flows have been considered. Using a simplified ghost point treatment, we consider the closest grid points as mirror points of the ghost points. Wall boundary conditions are imposed at the ghost points of the immersed boundary. The accuracy of the method has been investigated for various test cases. We show computed examples of supersonic flow past a diamond-wedge airfoil and compare with analytical results. Further we compute time accurate solutions of the compressible Euler equations for an incident shock over a cylinder and compare the pressure time history with other work. The supersonic viscous flow around a NACA0012 airfoil is computed, and the lift and drag coefficients along with the pressure coefficient profile are compared with the literature. The method is also tested for supersonic flow over a cylinder, and the computed skin friction profiles have been used to assess the accuracy. Lastly the supersonic flow around a 2D F-22 fighter aircraft with simulated jet engine outflow is shown to illustrate the flexibility of the method. The present method is built on a previously established simplified ghost point treatment, but performs better. The results are comparable, although not as accurate as other more complex methods.

In the search for new technology, new materials are prerequisite for major breakthrough. One of these classes of functional materials is the metal-organic framework (MOF). The MOFs offer higher surface areas because of its porous structure and a potential for improved adsorption activity than other currently used materials. This makes it attractive for physical adsorption, which is a hydrogen storage technique. Adsorption type storage systems are alternatives that have the potential to reach the goals for handling hydrogen in on-board storage systems. However, the transient processes during charging and discharging of a storage system play an important role in the utilization of the hydrogen adsorption storage systems, and the heat distribution in the sorption material plays a major role during charging and discharging of a storage system. The specific heat capacity for activated carbon, Norit R0.8 (1), and three microporous MOFs, Cu-btc (2), Fe-btc (3), and MIL-100(Fe) (4), have been measured, both for inactivated and activated material. The compounds were measured using an MDSC method on a Q2000 differential scanning calorimeter with an appurtenant liquefied nitrogen cooler system (LNCS). The heat capacities were measured from -180°C to 150°C. The uncertainties for the different measurements were determined; it varied from 5% to 7%, depending on the assumed water content adsorbed. Further the measurement accuracy was found to depend very little on the inert gases present in the sample. In addition to measuring the porous material´s specific heat capacity, is it performed and presented a literature survey on theoretical models and published data for both gas adsorption and heat capacities in porous materials. The experimental results are compared with published data on reference materials where possible, and a complete uncertainty analysis on the experimental results presented. The inactivated sample curves showed a general trend, where the heat capacities for inactivated material normally were higher than the heat capacities for the respective activated material, which most probably was due to higher water content in the inactivated material. A considerable number of measurements on each material were performed, without obtaining the expected results for the activated samples. The principal reason was that an unexplainable transition around -150 °C was present on almost half of the obtained data. The exact reason behind this anomaly was not found. However, the most likely error was the activation of the samples, based on analysis and investigation of the results. This presumption was stated mainly because the heat capacities for the inactivated samples increased in a smooth and continuous matter with increasing temperature, without this sudden heat capacity change around -150 °C. The conclusion is due to the time perspective of this work an assumption based on observations and personal experience. Further investigation on the matter is recommended, especially to find out if there was a problem in the actual activation procedure or a chemical change in the investigated materials.

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.