Further development of a two-dimensional thermal analysis code (G2DHeat) to include internal decomposition and charring ablation of insulation materials is presented. An overview of the structural changes made to the program code by implementing an implicit solution routine, including source term is given, before testing and verification of accuracy is performed. A kinetic model for decomposition reactions, as well as routines for handling the generated gas from the decomposition reactions, changes concerning the material properties and erosion of surface material are implemented and explained. Comparisons of results are made with similar results obtained by commercial programs. Possible reasons affecting the results are pointed out, before additional comparisons with experimentally observed measurements are performed. Based on the simulated results it is concluded that a great deal of testing remains for proper validation of the program. How to include better boundary conditions for simulating charring ablation is suggested and recommended for further development of the program.

This paper treats further development of the TEG injection process described in Bråthen (2007). An introduction to separation technology, conventional glycol regeneration and compact mixing is presented, as these are important parts of the alternative dehydration concept. Advantages, disadvantages and operational problems are pointed out, before the problems with the TEG injection process is described. Using hot stripping gas for regeneration of the TEG is one of the suggested improvements, but large glycol losses, large flow rates of stripping gas and oxidizing of glycol are found to be the consequences, thus making the alternative unfeasible. The only improvements used, are to use inline separators for the first separation stages and compact mixers for mixing of TEG and natural gas. A simulation model is developed using the simulation software HYSYS with the CPA EoS as fluid package. Both the absorption and the regeneration part of the process is modeled, and operational data from the Snøhvit LNG facility is used as reference. From simulations it is found that TEG injection requires about 50% more circulated TEG than conventional absorber dehydration to obtain the same water content in the dehydrated gas. The weight and volume of the absorption part of the process is however found to be considerably smaller than the operational process at the Kristin field in the Norwegian North Sea, thus partly compensating for the increased TEG circulation rate. Use of MEG and DEG instead of TEG for the injection concept is also simulated, but it is concluded that TEG is the best suited because of lower regeneration energy, lower absorbent loss and best dehydration performance for low to intermediate flow rates of stripping gas. MEG is found to be unsuited for dehydration because of very large losses of absorbent.

I denne oppgaven skulle jeg kartlegge de tekniske konsekvenser ved endringer i design av rør varmeveksler for varmegjenvinning og de teknisk/økonomiske konsekvenser for eventuell fjernvarmeutbygging ved redusert varmetetthet. Spillvarmen som skulle brukes ble hentet fra elektrolysehallen i et aluminiumsverk. Det var 170 ovner i elektrolysehallen. Varmen fra elektrolysehallen gikk ned i rør i kjelleren under hver ovn. For rør varmevekslere var det 2 alternativer kjølekappe rundt hvert rør til ovn og røykkjel der avgassen fra alle ovnene ble samlet i 4 store varmevekslere. Inntemperaturen til avgassen fra elektrolysehallen til varmeveksler var 400 C, og uttemperaturen til avgassen ut varmevekseleren i det første alternativet var 235 C. Innetemperaturen til avgassen fra elektrolysehallen til varmeveksleren var 400 C mens ute temperatur for røykkjelen var 120 C. I begge tilfellene så skulle vannet bli varme opp fra 50 C til 70 C. Røykkjelen egnet seg best til dette med dimensjonene: lengde 25 meter, diameter 0,1 meter. Antall rør er 10. Energien fra varmevekslere ble brukt videre til å dekke energibehovet til byen, både offentlige og private bygg. Det ble sett på 2 tilfeller energibehovet nå og energibehovet i år 2020. Det ble estimert med at energibehovet til byen blir redusert med 30% fra 2008 til 2020 i følge regjeringens soria moria erklæring angående energibruk. I byen er det også installert et pellets verk. Dette kan utnyttes til å samle rest energi og bruke dette for å dekke topplasten. Det totale energibehovet i 2008 var 21692169.2Kilowatt timer, mens det totale energibehovet i 2020 var 15184518.44 Kilowatt timer. Rørnettet ble distribuert på en total lengde på 8 km. Rørene ble lagt ned i en perfekt grunnforhold i sand og omtrent 1 meter under jorden. Maksimale trykk som er tillat i rørnettet er 16 bar. 10 meter stigning i terrenget tilsvarer 1 bar. Det høyeste toppen i terrenget var 70 meter. Det høyeste trykket blir derved 7 bar. Temperaturen til nettet ble på 70 C Rørnettet hadde en optimal diameter på 240 mm og kostnaden per meter ble i 2008 227 kr, mens i 2020 ble kostnaden 248,84 kr per meter. Den totale distribuerte kostnaden ble i 2008 på 1816071.664 kr, mens den i 2020 ble den totale distribuerte kostnaden på 1990779.649 kr. Kostnaden per Kilowatt timer ble i 2008 på 0,08 kr. Mens den i 2020 ble på 0,13 kr per Kilowatt timer. For selve anleggskostnadene så ble det betraktning til at investeringskostnadene var 1,5 kr per Kilowatt time. Det medførte at anleggsinvester ble 32,538,254 kr. For anleggskostnadene ble det antatt at man fikk 30 % støtte av Enova. Totale Anleggskostnad ble da henholdsvis 14223167.5 kr i 2008 og 12588089 kr i 2020. Dette medførte at i 2008 ble det anleggskostnaden 0,66 kr per Kilowatt time, i 2020 ble anleggskostnaden 0,89 kr per Kilowatt time. Dette medførte at de totale kostnadene per Kilowatt time økte med 30 % når varmebehovet sank med 30 %.

The following paper presents HVAC system commissioning activities, highlighting the most critical techniques and features to consider when commissioning the underfloor air distribution (UFAD) system. UFAD systems are non-standard and unique and therefore a special attention is needed to some issues and situations specific only for UFAD installations, e.g. coordination of the raised access floor, carpet and furnishings, temperature stratification etc. Some of the most important tests to be performed during commissioning of UFAD systems, are the air leakage, air stratification and thermal decay testing. In order to achieve successful operation of UFAD, the active participation of all involved parties, e.g. architects, interior designers, HVAC designers, contractors etc. is needed since the very beginning of the project. Commissioning of UFAD just requires a discipline, structured approach and commitment from all participants involved. The practical study involved assessment of expected UFAD performance at the Sparebank kvartalet office building complex in Trondheim, Norway. The underfloor plenum was not properly sealed, creating a significant risk of future energy waste. The openings in the raised access floor construction also lead to the dust and dirt accumulation in the plenum. This in its turn would not only impair indoor air quality, but could also lead to the malfunction of mechanical equipment installed in the plenum. Trying to seal the plenum after laying down the carpet was found to be difficult, costly and time consuming. Even though relatively good air distribution in the entire floor was achieved, some diffusers (automatically controlled) are located too close to the workstations and it will be probably needed to rearrange their layout in order to avoid draught complaints by occupants. The easier commissioning and better performance of UFAD in Sparebank Kvartalet could actually be achieved in a less time consuming and costly way if the commissioning would start early in the pre-design phase, with a well established commissioning plan.

SammendragAnalyse av konsekvenser ved tiltak for bygging av hus med særlig lavt energiforbrukDenne oppgaven er knyttet til planlegging og utvikling av lavenergi bolighus. Spesielt gjelder dette de nye kravene som ersatt i den norske standarden NS 3700:2010 Kriterier for passivhus og lavenergihus - Boligbygninger. Standarden er utviklet forsertifisering av tre forskjellige klasser med lavenergiboliger for norske forhold. Denne oppgaven omhandler i hovedsakpassivhusspesifikasjonen, som er den strengeste klassifiseringen.Det er blant annet utført beregninger på forholdet mellom energibruk og gulvareal. Disse tyder på at varmetransport vedtransmisjon er den dominerende parameter for energitap i et lavenergibygg, på samme måte som for en normal standard bygning.Dette innebærer at den lineære korreksjon for energibehov som er gjort i NS 3700 vil lette kriteriene for å kvalifisere små bygningermed samme bygningsstandard som større bygninger. Likevel, siden beregningene viser at forholdet mellom gulvflate og spesifikkenergibruk ikke er lineært, vil kravene være strengere for små bygninger.Standarden gjør videre bruk av lokale klimadata for kontrollberegninger mot energikravene. Da det er mangel påstandardiserte timebaserte data for de fleste norske steder, er det i dette arbeidet undersøkt hvordan interpolerte data, generert fraulike klimadatabaser, samsvarer med standardiserte offisielle værdata. Undersøkelsene viser at de interpolerte dataene avviker frastandardiserte måledata, spesielt for dimensjonerende forhold. Dette indikerer at energiberegninger med lokale timebaserteklimadata blant annet kan underestimere bygningens oppvarmingsbehov.For kravene til netto oppvarmingsbehov er det også gitt en klimakorreksjon basert på årsmiddeltemperatur for angittlokalisering. Undersøkelser på ulike klimasteder viser at denne gjennomsnittsbaserte parameteren ikke er den beste indikatoren pågitt varmelast for ulike lokaliseringer. Beregningene viser også at det er mulig å sertifisere en passivkvalifisert bygning for Osloklimaogså i kaldere klima.Det er videre undersøkt varmtvannets andel av varmebehovet i en lavenergibygning og effekten av varmegjenvinning avventilasjonsluft. Disse undersøkelsene viser at varmtvann representerer det dominerende energibehovet i energieffektive boliger,samt viktigheten av fungerende varmegjenvinningssystemer med høy virkningsgrad.Avslutningsvis konkluderes arbeidet med at den nye standarden er mer fokusert på detaljerte spesifikasjoner enn denoriginale standarden og implementeringene i Sverige og Finland. Likevel er de resulterende kravene til oppvarmingsbehov mindrekrevende enn for de andre nordiske standardene med tilsvarende bygningsutforming og klima, og varierer ikke alltid forutsigbart forde ulike forhold.Una Myklebust Halvorsen, Trondheim juni 2010

In a refrigerated seawater (RSW) system using carbon dioxide (CO2) as the refrigerant, a variable bypass valve was installed in front of a suction gas heat exchanger (SGHX). A simulation tool was developed and utilized to optimize the systems transcritical performance (COP) with respect to the gas cooler pressure and choke valve inlet temperature for cooling and combined cooling and water heating. The simulations indicate that the RSW system performance can be increased compared to running a system with a traditional non-variable suction gas heat exchanger, but only when the cooling water temperatures are high (above ~25°C) or where air is used as the cooling medium, for instance commercial or mobile refrigeration. It is strongly recommended that a system to be used for simultaneous cooling and heating should have an improved design compared to the current setup, as this mode of operation shows low cooling capacity and poor energy efficiency.

This thesis applies the framework of input-output analysis to the transportation of goods driven by the consumption of French household.It was found that transportation of goods amounts to 7 % of the average 22,4 tons of CO2 emitted by French households and that78 % of the emissions occured inside the EU 15, France included.In fact, 92 % of the tons consumed by French households are produced inside the EU 15 and are mainly transported via roadwhereas the remaining tons, coming from other countries, are mainly transported by ships.Consequently, the carbon efficiency of the transportation inside the EU15 is low compared to imports from other countriessince road transportation emits 40 times more carbon dioxide per tonne-kilometer transported.This demonstrates the need for an ambitious policy of transfer from road to rail, water or maritime ways via the development of the appropriate infrastructure and the combination of theadvantages of the different modes, flexibility of the road transporation associated with mass and environmentally friendly transportation of rail, waterway and maritime mode.Furthermore, the study gives some knowledge on the indirect emissions associated with French households, which correspond to the combination of the emissions driven by the transportation of goods withthe emissions associated with the production of these goods. It was found that petroleum products, food related sectors and the coal sector are the main contributor of the indirect emissions associated with French households representing as much as 57 % of them. As a result, future studies should focus on those sectors in order to isolate path of improvement both in production, consumption and transportation patterns.

In this diploma thesis, the possibilities to enhance the process production and energy efficiencyas well as the energy recovery potential of PFA 2 at Hydro-Sunndalsøra have been determined.To identify the potentials for energy recovery, it has been conducted energy balances. The resultsfrom the balances give an overview of the waste heat sources and their total energy content, togetherwith the temperatures at which they are available. The total energy in the waste heatsources for PFA 2 was found to be 17.8 GWh/year. The largest waste heat sources were localisedin connection to the cooling agent of the casting ingot machine. Here disappears 12.32GWh/year through cooling water within a temperature range of 10 to 30°C as well as convectionand radiation to surrounding. The cooling water section one was determined as the most promisingheat recovery potential with 7.47 GWh/year. Furthermore the initialisation of liquid aluminiumalloy was revealed as a waste heat source with 5.48 GWh/year. Here disappears 3.34GWh/year through the flue gas of the furnace within a temperature range of 288 to 1,100°C andcreates the most promising heat recovery potential at the furnace.The energy saving potential is divided into three groups: energy saving by existing equipment,optimising of equipment and waste heat recovery. Here energy saving by existing equipmentreveals 26.4 MWh/year for an improved control quality of the melt temperature. The greatestpotential for energy saving by optimisation of the equipment was found to be 1.98 GWh/year forthe implementation of regenerative burner. Furthermore effects an installation of a furnace pressurecontrol system 689.14 MWh/year less energy consumption due to the avoided false air. Thegreatest energy saving potential for waste heat recovery was estimated to 1.65 GWh/year for thepreheating of charged metals to 300°C, instead of 20°C. The preheating also leads to improvedsafety, because of the elimination of moist metal in the furnaces, and increases the process production,as a consequence of larger melt capacity. Furthermore, heat to power solutions revealedthe use of favourable electricity production by the generation of waste heat. Here the greatestgeneration potential was found to be in the flue gas from the furnace. A common Rankine cycle,with a direct heat recovery design and water as working fluid, was estimated with a recoverypotential of 1.1 GWh/year. With the use of an organic Rankine cycle the potential can be recoveredto 489.8 MWh/year for an indirect heat recovery design and pentane as working fluid. Thereare still some challenges associated with flue gas heat exchangers (dust) and operation of suchpower generation plants at alternating heat loads, but the technology is under rapid development.The waste heat generation potential for the casting ingot machine was determined with 411.3MWh/year for an ideal organic Rankine cycle heat recovery design, within a temperature rangeof 58 to 90°C and R 134a as working fluid. An alternative ideal organic flash cycle layout revealed253.4 MWh/year (expander = 0.6) respectively 416.5 MWh/year (expander = 0.6), within atemperature range of 36 to 90°C and butane as working fluid. These considerations have lowerefficiencies compared to the furnace layouts caused by the low application temperatures (TBoiler <90°C).

Ejector systems have been a field of research for many years. One of the latest topics are transcritical cycles with R744 refrigerant. The main reason of installing ejectors in that type of systems is the recovering of the pressure energy, lost in the classic cycles during the throttling processes.The thesis consists basically of two parts, which both of consider the topic of parallel ejector operation. In the third part conclusions are presented.The first part is a simplified feasibility study for a concept R744 cycle with three different ejector geometries working in parallel. MS Excel spreadsheet was created for general parameters calculations and for specific motive nozzles mass flow estimations.The second part contains results of measurement procedures on the SINTEF test facility. First, single ejector operation was examined. Basing on the test results, characteristic of P2GGC ejector geometry has been created. Later on, a new module with two different geometries (P2GGC and A2CDC) working in parallel has been built on the rig. The parallel ejector operation has been examined, as well as single operation of each geometry. The results has been compared, considering the influence of each operation on the system parameters.In the third part final conclusions are presented. Some ideas of further work are mentioned as well.

This thesis includes a brief presentation of the different losses developed in high head Francis turbines, where special attention is paid to the losses in the guide vanes due to the head covers deflection. The different factors determining the extent of the leakage flow are thoroughly examined. Also, since the guide vane facing plate and the head covers are exposed to serious wear due to the presence of sand particles in a high accelerating flow, efficiency measurements of sand eroded and repaired turbines are presented. In addition, results from efficiency measurements of Francis turbines with different clearance gaps are included to underline the severity of the clearance gap between the covers and the guide vanes. The thesis presents a numerical approach to calculate the head covers deflection. And the scope of this work is to develop a simplified 2-D model, which calculates the head covers deflection within a certain order of accuracy. Thus a 3-D modelling of the head covers deflection is also included with the purpose of validating the 2-D modelling. Furthermore, a discussion of the efficiency with respect to the design of the head covers is performed to describe the potential of increasing the hydraulic efficiency by altering the design method. Also, a numerical computation of the leakage flow in the guide vanes due to the head covers deflections, is presented to better visualize the effect from the clearance gap between the head cover and guide vane facing plate. Also, to underline the severity of large clearance gaps, the guide vane has been modeled with four different sized clearance gaps. Finally, an analytical interpretation of the leakage flow is included to evaluate the numerical calculation of the leakage flow.