Energiforbruket til fritidsboligsektoren i Norge har de senere årene hatt en dramatisk økning. Fremtidsprognosene anslår at dersom ingenting gjøres vil denne utviklingen fortsette til fritidsboligsektoren står for en merkbar andel av det totale strømforbruket. Tall fra SSB tyder på at det ikke er antallet nybygde hytter som i hovedsak bidrar til det økte forbruket, men økt standard på allerede eksisterende fritidsboliger. Det økte forbruket kommer både som en følge av innleggelse av vann med påfølgende behov for frostsikring i ubebodde perioder, og som en følge av økt forbruk i bebodde perioder. En gjennomgang av tidligere arbeid viser at det er gjort mye godt arbeid og mange gode vurderinger som danner grunnlag for en videre prosess. Dessverre lider tidligere simuleringer av et par grove forenklinger som gjør at arbeidet må dimensjoneres og verifiseres på nytt før det kan benyttes som annet enn parameterstudier og løsningsforslag uten å vise nødvendig dimensjonering. Tidligere arbeid har likevel med tydelighet vist muligheten for, og gitt gode forslag til utformingen av en rekke tiltak og vurderinger. De viktigste er listet opp under:-Klarlagt den store betydningen av en indre, ekstra isolert og frostfri sone(Børset, 2009)-Vist muligheten for utnyttelse av energitilførsel fra sola:oPassiv soloppvarming (Amble, 2008)(Bratteberg, 2009)oSolfangere og luftsolfangere (Børset, 2009)(Bøckman, 2010)oSolcellepanel (Børset, 2009)(Bratteberg, 2009)-Potensialet for frostsikring gjennom grunnkobling er utforsket (Amble, 2008)-Bratteberg sin mastergrad (Bratteberg, 2010) illustrerer viktigheten av først og fremst å redusere strømforbruket. Videre viser studien at LCA vurderinger kan være nyttige for å oppnå utslippsreduksjoner.-Hybrid ventilasjon av ytre sone er optimalt for en fritidsbolig (Bøckman, 2010)I denne oppgaven er det lagt ned et omfattende arbeid for å sikre mer realistiske simuleringer som også tar hensyn til tidligere arbeider. Det er vist at med en realistisk og optimalisert modell som benytter enkleste form for ventilasjon av indre sone vil energiforbruket bli 3.3 ganger høyere enn for tidligere løsninger, med mindre ekstra tiltak implementeres. Slike tiltak kan være å ventilere indre sone gjennom en luftsolfanger eller en jord-luft varmeveksler. Det har ikke lyktes å simulere en løsning med jord-luft varmeveksler tilstrekkelig realistisk til å det er verdt å ta med. Derimot har det vist seg at selv en simpel luftsolfanger kan redusere energibehovet til frostsikring til 107 kWh per år. Dette er fortsatt dobbelt så høyt forbruk som antatt i tidligere arbeid. Det er både påpekt flere muligheter for optimalisering av tidligere løsninger og luftsolfangeren og det er til en viss grad mulig å skalere opp tidligere løsninger. Derfor antas det at løsningene fortsatt er gjennomførbare, men krever ytterligere optimalisering. De viktigste forslagene til optimalisering er: -Optimalisering av luftsolfangeren.-Dersom solfanger og akkumulatortank benyttes for frostsikring, foreslås det å benytte flere små tanker kombinert med vakuumrørsolfangere i stedet for løsningen i Børsets mastergrad. -Dersom metoden med grunnkobling benyttes for frostsikring, foreslås det å jobbe videre med geometrien til indre sone, alternative måter å føre grunnvarmen inn i bygget på, og bedre simulering av de termiske forholdene i grunnen. Gjennom arbeidet med den nye modellen ble det tatt hensyn til anbefalte materialvalg fra mastergraden til Bratteberg. Resultatet viser at det er mulig å bygge en fritidsbolig med tilnærmet lik prestasjon som tidligere og samtidig trolig redusere CO2 utslippene i forbindelse med byggeprosessen med 28 tonn CO2. Viktige tiltak for å oppnå dette har vært å benytte cellulosefiber til isolering, massivtre til vegger og jordgulv for å oppnå tilstrekkelig termisk masse. En undersøkelse viser at jordgulv, selv om det er utradisjonelt, kan fungere veldig godt som gulv i fritidsboliger.For ytre sone anbefales det å ventilere med ventiler som er selvregulerende med hensyn på vind. Et luftskifte på 0,29 h-1 antas å være passelig mengde ventilasjonsmengde. Forholdene rundt kondensering i ytre sone er noe usikkert, spesielt for klima som er varmere og fuktigere enn Østersund. Derfor anbefales det å se videre på et VAV anlegg som regulerer den naturlige ventilasjon med hensyn på temperaturer og RF inne i ytre sone og utendørs. Det antas at dette vil gi vesentlig tørrere forhold inne i ytre sone. Energibehovet forbundet med ventilering av indre sone er ikke stort, i størrelsesordenen 35 kWh/år. En simpel luftsolfanger har vist seg å gi vesentlig reduksjon av dette energibehovet, og til og med gitt netto varmetilskudd til indre sone. Luftsolfangere er rimelige i innkjøp og derfor anbefales det å benytte slike i fremtidig simuleringer. En litteraturstudie antyder også sterkt at en løsning med jord-luft varmevekslere kan bidra med netto energitilskudd.

Hovedformålet med oppgaven er å etablere en fungerende metode for forsegling av varmerør ved hjelp av induksjonssveising. Varmerøret skal produseres i nikkel og ha kalium som arbeidsmedium, og det stilles derfor strenge krav til påfylling, vakuumering og lukking av påfyllingsrøret. Siden nikkel reagerer med luft og danner nikkeloksid, og kalium reagerer med både tørr og fuktig luft, ble det nødvendig å utføre påfyllingen og forseglingen under vakuum.I sammenheng med denne problemstillingen ble det utført et litteraturstudium innen induksjonsoppvarming og induksjonssveising. Her ble det fokusert på klargjøring av de ulike parameternes betydning, samt hvilke verdier som gav best mulig resultat.Det ble laget en forsøksrigg for å undersøke mulige fremgangsmåter for induksjonssveising under vakuum. Hovedfokuset var på å fremstille en gasstett sveis hvor resultatet kan overføres til hovedriggen for påfylling og forsegling av varmerøret. Hovedriggen var ikke klar ved oppgavens slutt.Eksperimentene utført ved forsøksriggen resulterte i en gasstett sveis, et resultat som lot seg reproduseres.I tillegg til forsøkene ble det gjennomført numeriske beregninger ved hjelp av FEM-vektøyet Comsol Multiphysics. Simuleringene hadde som formål å undersøke temperaturutviklingen rundt sveisesonen, samt å forstå betydningen av å variere de forskjellige parameterne som kunne påvirke sveiseprosessen.Som resultat av eksperimentene og de numeriske beregningene ble det oppdaget utfordringer relatert til implementeringen av induksjonsprosessen i påfyllingsriggen. Det viste seg at det opprinnelige designet til påfyllingsriggen kunne gi en uønsket lav frekvens. Derfor ble det utført simuleringer i Comsol for å undersøke hvilket design som passet best til formålene. Løsningen ble å inkludere en RF-gjennomføring, og redusere trykkbeholderens materiale i nærheten av lederne til spolen, dette skal føre til en reduksjon av den induserte motstanden.Med utgangspunkt i disse løsningene samt resultatene fra sveiseprosessen ble det laget tegninger for oppsettet til påfyllingsriggen.Med bakgrunn i litteraturstudiet, forsøksresultatene og de numeriske beregningene ble det satt opp en forsøksplan. For å kunne oppnå en gasstett sveis er det nødvendig å teste den nye riggen før påfyllingsprosessen startes. Det er i oppgaven laget en anbefaling av startverdier for de ulike parameterne, samt en forklaring av hvordan en bør justere disse for å oppnå ønsket resultat. Det er altså ikke sikkert at de angitte verdiene vil resultere i en gasstett sveis, hensikten er å redusere antall nødvendige forsøk før påfyllingen kan iverksettes.Oppgaven avsluttes med forslag til videre arbeid, med den hensikt å optimalisere resultatene fra denne oppgaven.

The Höegh LNG FPSO is designed for a CO2 removal of a gas stream containing 12.3% CO, but has a desire to add discuss alternative CO2 compositions.The thesis aims to give an introduction of some CO2 removal technologies. The work of this thesis is comprised of a literature study and evaluation of different aspects of these technologies. The evaluation includes discussing the aspects of the technologies and also collecting comparative data.There are three main technologies for CO2 removal; amine, membrane and molecular sieve. These were chosen from the literature study to be most suitable for removal of CO2 for LNG production. Two combinations are most relevant, the amine-membrane, and the amine-molecular sieve.Both the molecular sieve and the membrane have certain issues with regards to hydrocarbon losses. The best solution is to use both of these losses as fuel for the turbine. This however requires the turbine design to be adjusted accordingly.The molecular sieve is suggested used for CO2 compositions of less than 0.1%. The amine solution is suggested used for CO2 compositions between 0.1% and 6%. The membrane-amine solution is suggested for CO2 compositions above 6% because of the high bulk removal capability of the membrane and the ability for the amine process to remove CO2 on the lower part of the scale.

Due to the increasing demand for LNG, more environmental friendly regasification solutions are of interest. Aker Solutions has developed a concept for zero emission regasification of LNG, where the regasification train is heat integrated with an oxy-fuel power and steam plant. The oxy-fuel combustor burns part of the send-out gas in an oxygen enriched environment. The flue gas produced is CO2 rich, making CO2 capture feasible. 95mol% pure oxygen is produced by cryogenic distillation in an ASU. Today, oxy-fuel combustion is not economical feasible, mainly due to the significant power demand in the ASU and the CO2 Compression and Purification Unit (CPU). This thesis investigates opportunities of reducing the power consumption in the plant. Pinch analysis is used to evaluate the heat integration in the Aker Solutions’ concept. Simulation models are created in Aspen Hysys to investigate possibilities of integrating the ASU with the power and steam plant, and to find the impact of changing the oxygen purity. In addition the use of membranes to separate air is discussed. The heat integration was evaluated in terms of sequence of the pair matches, and placement of Heat Transfer Fluids (HTFs). The sequence of the streams was found acceptable. However, changing the HTF in LNG heater 2 and 3 from MEG/Water to Methanol could be beneficial. The freezing point of Methanol is lower than that of MEG/Water; hence the HTF can be shifted to a lower temperature. Because LNG has a higher h-value than the hot streams, ∆T between the LNG and the HTF should be lower than that of the hot fluid and the HTF. If the oxygen purity was set to 90mol%, the load of the CO2 CPU and the condenser duty of the N2/CO2 distillation were increased by 10% and 65% respectively. If the purity was increased to 97mol% the opposite results were obtained. Although increasing the purity leads to savings in the CO2 CPU, this unit only accounts for a small part of the overall power consumption compared to the ASU, hence the impact on the ASU is of greater concern. For the ASU, decreasing the purity would lead to some energy savings. However, the required equipment size of the unit would increase. If the purity is increased, the separation of Argon is required in the distillation column, thus a significant increase in energy of separation is experienced. In addition the capital expenses of the ASU are increased, due to implementation of a supplementary distillation column. Based on the previous facts, it was recommended to keep the oxygen purity at 95mol%. If integrating the ASU, cryogenic LNG should be used to cool the air upstream and downstream the air compressor. Results from Hysys showed that this would lead to 18 % reduction in external utility consumptions. In addition the compressor work of the ASU would be decrease by 14%, and the yield of the LP turbine would increase with 2MW. Today, membranes are not capable of producing large quantities of oxygen. However, there exist some membranes with great potential. The most promising membranes are found to be MIECs with a perovskite structure, especially Ba0.5Sr0.5Co0.8Fe0.2O3-δ. At 800ºC the oxygen flux of these membranes are found to be approximately 1.56∙10-6 mol/scm2, and the oxygen purity obtained is above 99mol%. The thickness of one of these membrane were found to be 1.8mm, hence more than 1∙109 membranes are required to produce enough oxygen for the oxy-combustion plant. Although these membranes have a great potential, they need to be further evolved before implemented to oxy-fuel power plants.

The lattice Boltzmann method is a modern method in computational fluid dynamics. Its primary use is the simulation of incompressible flows. It has computational advantages over conventional methods like the finite volume method. However, the implementation of boundary conditions is still an unsolved topic for this method. The method is defined on a Cartesian grid such that curved walls need special treatment as they are generally not aligned with the grid lines. We investigated a number of straight and curved boundary conditions and performed four different benchmark tests to verify these. Based on a formulation for curved walls with no-slip from the literature, we showed that this method could be extended to simulate flows with arbitrary velocity boundary conditions. Our scheme conserved the second order accuracy of the lattice Boltzmann method in time and space.

Yara Glomfjord is the north most production facility of compound fertilizer in the world and produces annually about 500 000 tons NPK and 200 000 tons CN. The general energy system of the process plant utilizes steam as the main energy carrier for the entire production site. Yara Glomfjord has today a general lack of steam, and steam is produced in EGA boilers approximately 75% of operational time to cover all heating tasks. The main objective of this Master thesis is to analyze energy flow in in the factory to identify energy saving potential, and later to suggest improvements for the CN-evaporator system in order to retire the use of EGA boilers and supply excess heat for other heating tasks in the factory.First off analysis was made on general energy flows in the factory. This was done in order to reveal potential for energy savings and to clarify which paths to choose for further heat integration. The result of the analysis shows that latent heat flows are of far greater importance than sensible heat flows to the general steam balance at Yara Glomfjord. It was also identified that the large potential for latent heat recovery lies within the evaporator equipment.Next up this text suggests investment in evaporator equipment in order to integrate latent heat, so that the overall steam consumption goes down. Three different suggestions were presented and analyzed in detail in the document: CN-Evaporator System Design. The most proving suggestions are new equipment coupled in cascade with old evaporators or a new independent MVR evaporator in front of old solution. Both suggestions are found to retire EGA boilers completely and also supply excess heat for other heating tasks. This text recommends one of these two suggestions.To suggest new improvements in the CN-evaporator system Epcon Evaporation Technology AS were involved. Testing at Epcon’s facilities in Trondheim indicate a new possibility. For the suggested retrofit cascade evaporation system, submergence of boiling pressure is possible. These findings supports the recommendations from this text to invest in a new evaporator coupled in cascade with the old solution with submergence of boiling pressure. In this way the energy savings in question can be implemented with only a small investment and almost no energy cost in a vacuum pump.As a huge potential for energy savings was found possible at reasonable cost and at a manageable technical level, the findings of this Master thesis hopefully settles the steam issues of the Yara Glomfjord compound fertilizer plant once and for all.In light of the late findings of this project, with the possibility of submergence of boiling pressure a hint is also sent to Yara Porsgrunn. As a great role model for Yara Glomfjord they utilize latent heat, but at the cost of expensive compressor work and not with submergence of boiling pressure which this text clearly states to be the superior technology.

In the present study the wake behind a scaled; Horizontal Axis Wind Turbine (HAWT) has been investigated. The experiments were performed at the Department of Energy and Process Engineering, at the Norwegian University of Science and Technology, NTNU. The turbine was installed in the wind tunnel at the department and measurements were performed at several distances behind the turbine to examine the development of the flow. A five-hole pitot probe was applied as measurement instrument. The instrument made it possible to calculate both size and direction of the velocity components.Through the experiments, characteristic curves of the turbine and grid measurements over the cross-section of the wind tunnel, were obtained. The power and thrust coefficients were measured against the local velocity ratio at the tip of the blade, the 'Tip Speed Ratio' (TSR). The power coefficient had a peak at TSR=5,5. The maximum value at this point was 0,45. The highest measured thrust coefficient was 1,15, achieved at TSR=10,3. During the experiments the turbine operated at optimal conditions, at the highest obtained power coefficient.Measurements behind the turbine found that the axial velocity distribution developed as expected. A significant velocity deficit was measured in the wake behind the turbine, which gradually decreased with increased distance to the turbine. Due to the presence of the hub and tower, the middle of the wake was characterized by disturbances. Moving down the wake the profile got more symmetric. The tangential profile was almost symmetric about the origin, right behind the turbine, but drifted to the left at increased distance downstream. Contribution from the tangential components were gradually reduced further down the wake.The tower shadow moved with the rotation of the wake, in clockwise direction, as a region of lower velocities than the prevailing wake. Further downstream the tower shadow merged with the surrounding wake.The rotational axis relocated in the wake behind the turbine. Downstream, measurements showed that the center of rotation moved to the left of the origin. To investigate if the tower was responsible for the experienced downshift, an additional tower was mounted to the tunnel roof, above the turbine. The additional tower created symmetry about the hub and gave a symmetric development of the flow field. Thus, it was concluded that the tower was responsible for the relocation of the rotational axis.

Sperre AS produserer i stor grad hele ROV konstruksjonen sin i aluminiumslegeringen AA6082-T6. Dette er et velegnet materiale for oppgava, men med noen mangler.Denne oppgava fokuserer på elektronikksylindrene til ROV-en, disse er per idag produsert i den ovennevnte aluminiumslegeringa. Man vil i framtida ned på store havdyp, ned mot 6000 meter. Når man skal så dypt vil disse elektronikksylindrene påføre konstruksjonen mye vekt og volum, både direkte pga større masse aluminium og indirekte ved at man trenger mye oppdriftsmateriale.Ved å benytte seg av kompositt og egna produksjonsmetode vil man kunne produsere samme tanken, med svært mye bedre egenskaper. I denne oppgava er det sett på metall-innerforing for spinning av kompositt på utsida og derfor oppnå ønska styrke, samt generelt design av sylinderen. Det er også foreslått design uten innerforing, men da produsert ved hjelp av kompositt-duk. Hvilket materiale som er best egna til innerforing og hvilken kompositt som har de beste egenskapene er også vurdert.Som deloppgave er det utført mekanisk testing på sveist aluminiumslegering for å verifisere DNV standardencite{DNV271}, samt vurdere om man ved forenkla varmebehandling kan gjenopprette noe av styrken til metallet.

Abstract— The object of this paper is to investigate the influence of wave-current interaction on a tidal turbine. An experiment at Norwegian Marine Technology Research Institute (MARINTEK) has been carried out, and a CFD analysis has been performed in order to enhance the understanding of the wave induced loads on the tidal turbine. These loads are known to be the governing forces and it is therefore of great importance to predict them accurately. The CFD results are found to be trustworthy with calculated values close to experimental data. In addition to the wave-induced forces, the wake characteristics and wave influence on the wake are investigated. Results from Blade Element Moment Theory (BEM) are also compared to validate the accuracy of this method. CFD is a powerful tool if used properly, but it is computationally expensive, especially when dealing with complex geometry like a tidal turbine. A high performance computer (HPC) has been used to carry out the transient CFD wave-current simulations in order to obtain reliable results within reasonable time.

The governing purpose of the thesis is to develop a chair concept based on a tilting mechanism called VAPAC. This chair concept has many potential ergonomic and environmental benefits that should be included and developed in the design. The report starts with an analysis of different segments within the chair market. Based on an evaluation, office chairs was chosen as the segment for the VAPA-Chair. Due to an interesting tilting idea suggested by the Supervisor/Concept originator, a test rig was built in order to try out a chair concept using straps for the tilting mechanism. This assignment was not originally one of the main tasks in the problem definition of this thesis . Due to curiosity and expectations for the idea, it was chosen to include this assignment in the thesis. A user survey reviled that this tilting idea offered an exciting and comfortable sitting experience. The concept using straps as tilting stringers was therefore developed further and important lengths and angles regarding the tilting mechanisms were settled. A problem occurred due to the risk of the chair tilting completely around if the user leans too much forwards or backwards in the chair. Making the stringers stiff so that they can withstand pressure when introduced to a load solved this problem. The tilting function was still the same as with the regular straps because the stringers were attached in joints, allowing the stiff straps to rotate freely. An Idea using turnbuckles as stringer was developed. This solution ensured the required stiffness as well as possibilities for height adjustment and a stop mechanism for the tilting. The terms “Ergonomic” and “Environmental friendly” is introduced, and important elements from these was set as requirements for the chair concept. Design sketches, doodling and brainstorming generated ideas for different concepts. Different functional concepts was introduced and evaluated as sub-parts of the chair. One concept was chosen for each part resulting in a holistic concept for the chair.The preliminary work results in a final concept, which is presented in the form of hand sketches and a 3D model using the program NX 7.5 Mechatronics . A lot of time was spent on modeling a simple and functional design with ergonomic and environmental friendly solutions.A material analysis was conducted regarding the bearing structure of the chair using the Life cycle analysis tool Eco-indicator 99. The analysis compared aluminum and steel. Due to low environmental impact using recycled aluminum, this material was chosen for the VAPA-Chair. A life cycle analysis was also conducted on the chair using the program CES Edupack. The analysis showed that the part of the chair’s lifecycle that impacts the environment the most, is the production of materials. Based on these results, it is recommended that the VAPA-Chair should focus on weight optimization of the chair and use as much recycled aluminum as possible in the production. Based on results from the report, a list of recommendations for further work is presented.