Energieffektiviserande åtgärder har stor betydelse för den totala effekten på vårt klimat. Lägre energiåtgång leder till reducerade koldioxidutsläpp och att naturens resurser inte belastas lika hårt. En av de mest kostnadseffektiva åtgärderna för att minska byggnaders miljöpåverkan har visats vara att investera i den energieffektiva belysningsteknik LED, och i kombination med dagsljus- och närvarostyrning finns en stor potential att spara energi.Syftet med detta examensarbete är att studera hur bland annat elförbrukningen, värme- och kylbehovet, ljusmiljön och driftkostnaderna för en belysningsanläggning påverkas av att byta ut traditionell belysning mot LED i befintliga kontorslokaler, samt implementering av dagsljus- och närvarostyrning. Detta har gjorts genom bland annat el- och ljusmätningar, flertalet datorsimuleringar, enkätundersökningar och intervjuer som en del i ett befintligt projekt med ÅF Lighting, som gick ut på att två olika LED-lösningar installerades på två kontorsplan på ÅF:s huvudkontor i Solna. Med hjälp av datorsimuleringar har undersökningar gjorts av bland annat kontorens tillgång till dagsljus i DIVA-for-Rhino, kontorens ljusnivåer i diaLUX, hur kyl - och värmebehovet påverkas i IDA ICE 4.7, ekonomiska besparingar i ecoCALC samt belysningens elförbrukning i Mitec Monitor.Elmätningar under en månad av de nya belysningsanläggningarna på plan 5 och plan 10 visade på en reducering av belysningens elförbrukning på 71,6 % respektive 68,1 % under denna period.Energisimuleringar över ett år i IDA ICE visade att den totala energianvändningen för båda kontorslandskapen reducerades med cirka 12-14 % efter bytet till LED-belysningen och implementeringen av dagsljus- och närvarostyrning. Största faktorn till denna besparing är att kylbehovet för plan 5 och plan 10 kunde reduceras med 19 % respektive 17 %, eftersom den mer energieffektiva belysningen och styrningen av denna genererar mindre värme än den befintliga belysningen. Simuleringarna visade även att belysningens totala årliga elförbrukning reducerades med 70 % på plan 5 och 63 % på plan 10.En grundlig LCC för de nya belysningslösningarna på plan 5 och plan 10 visade att investeringskostnaderna för de nya LED-lösningarna är högre än den totala driftkostnaden över livscykeln för den befintliga belysningen. Dock är driftkostnaderna för de nya lösningarna mindre än en tredjedel av kostnaderna att driva den befintliga belysningen, och de totala koldioxidutsläppen kan reduceras med närmare 70 % i och med utbytet.Denna fallstudie har visat att det finns enorm potential att spara energi och minska driftkostnaderna genom att investera i energieffektiv LED-belysning i kombination av dagsljus-och närvarostyrning, samtidigt som det kan ha positiv inverkan på ljusmiljön. Dock är investeringskostnaderna av de nya LED-lösningarna för stora för att installation av just dessa lösningar ska vara ekonomiskt försvarbart idag. / An important measure to reduce buildings’ environmental impact is to make the artificial lighting more effective, which is the biggest electricity consumer of Swedish office buildings and accounts for more than 30 % of the total electricity consumption.A case study has been carried out in this master thesis as a part in an existing project with ÅF Lighting, where new strategic avenues has been explored in which to combine day- and electrical light in office landscapes in a smarter, more energy-efficient manner and at the same time improve the lighting environment.Two office spaces at the own head office of ÅF in Solna, Stockholm has been used in the case study, where two different LED lighting solutions got installed. One with pendant luminaries, desk lamps and downlights, and one with only recessed luminaires.Through several computer simulations, electricity and light measurements, questionnaires, interviews etc., it has been investigated how the heat and cooling load, electricity consumption, lighting quality and operating costs has been affected of the change of the lighting system. The lighting environment, daylight conditions, heat and cooling load, economical savings and electricity consumption for the two offices has been investigated in diaLUX, DIVA-for-Rhino, IDA ICE 4.7, ecoCALC and Mitec Monitor, respectively. The electricity measurements showed that the lighting solutions’ electricity consumption got reduced with 71,6 % on floor 5 and 68,1 % on floor 10 with the new LED lighting solutions and control systems during the investigated month.Through the IDA ICE energy simulations over a year it was shown that the total yearly cooling load to floor 5 and floor 10 got reduced with 19 % and 17 %, which can be explained by the lesser heat gain from the more energy efficient lighting and the controlling of this. Though a small increase in heating load, the total energy consumption got reduced with around 12-14 % on both floors. The simulations also showed that the total electricity consumption of the lighting got reduced with 70 % for floor 5 and 63 % for floor 10 after the change to the new LED lighting solutions and implementation of control systems.The LCC for the new lighting solutions showed that these have a higher investment cost than the total operation cost for the existing solution over the life cycle. However, the costs to run the LED solutions are less than a third of the operation costs for the existing solution, and after the exchange the carbon dioxide emissions can be reduced with close to 70 %.Through this case study it has been shown that the energy consumption from lighting can be highly reduced with the installation of energy efficient lighting in combination with smart control systems, and it can also have a positive effect on the lighting environment. However, the high investment costs of the LED solutions lead to the conclusion that installation of these solutions today is not economically justifiable.

<p>The current study has investigated two-phase refrigerant flow distribution in heat exchange manifolds. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow rate and gas and liquid distribution in the manifolds of compact heat exchangers. Twelve different manifold designs were used in the experiments, and CO² and HFC-134a were used as refrigerants. </p>

<p>Detta examensarbete är genomfört åt Sandvik Mining and Construction inom ramen för det statliga samarbetsprojektet MinBaS II. Sandvik Mining and Construction är ett av Sandvik koncernens affärsområden och har en världsledande position på marknaden för maskiner och tekniska lösningar för bergbrytning m.m</p><p>MinBas II är ett samarbetsprojekt mellan ett stort antal företag och universitet där staten står som huvudman och löper till 2010.</p><p>Uppgiften med examensarbetet var att se om det fanns någon metod för att kartlägga de interna transporterna och beräkna deras energiåtgång i en bergtäckt. I brist på en befintlig skulle det tas fram en ny metod och sedan testa denna genom att genomföra fältstudier i en bergtäkt tillhörande Skånska Makadam AB för att sedan göra beräkningar på energiåtgången där.</p><p>Volvo CE har under arbetet ställt upp med information och även givit oss SiteSimulation, ett simuleringsprogram för simulering av användning av deras maskiner.</p><p>En del av arbetet var också att utreda hur energiåtgången ändras om förkrossen placeras på en högre respektive lägre nivå än det ställe där bergbrytningen genomförs.</p><p>För att införskaffa underlag till beräkningarna har fältstudier genomförts i Skånska Makadam AB:s bergtäkt. Där gjordes bl.a. uppmätningar av den fysiska miljön som t.ex. mätningar av höjdskillnader, bedömningar av lutningar på backar och bedömningar av vägstandarder. Dessutom gjordes ett antal klockningar av cykeltider för olika fordon vilket senare fick fungera som underlag för att utvärdera hur vida Site Simulations resultat stämmer överens med verkligheten.</p><p>I resultatet går det att utläsa vilken den totala energi- och bränsleförbrukningen per ton är för respektive utvald produkt. Dessa värden är en sammanställning av förbrukningarna för de olika interna transporter som behövs under tillverkningsprocessen, från bergbrytning till kundutlastning av färdig produkt.</p><p>Arbetet med att utreda förkrossens placering genomfördes genom att en teoretisk sträcka ”tillverkades” i Site Simulation där sedan förkrossen placerades på olika nivåer i förhållande till startstället. De olika simuleringarna tydde på att optimal bränsleförbrukning uppnås vid en lätt sluttning mot förkrossen.</p><p>Vid simuleringarna med de nya Volvo maskinerna, gick det av resultaten att dra slutsatsen att energiåtgången per ton sten ökar samtidigt som även produktiviteten ökar.</p><p>Till sist kan vi dra slutsatsen att det hela bygger på att man gör en ordentlig förstudie och verkligen planerar upplägget av anläggningen vilket allt ifrån lagringshögar, transportsträckor och placering av krossanläggning i förhållande till dessa.</p>

<p>This final thesis contains three major parts, which all have been time demanding:</p><p>* Designing and construction of a small wind turbine.</p><p>* Designing and construction of an electrical system.</p><p>* Thesis with fundamental facts about wind, wind power and design.</p><p>The thesis contains basic theory in wind power and the energy systems it can be combined with. Different types of wind turbines, which components they consists of and important issues to consider when designing is also mentioned. In the end of this report the technique of our wind turbine will be presented. In the end you can also read about our experiences during the time of designing and construction.</p>

<p>This thesis has been written with our society’s current energy-situation in mind.</p><p>Although it only deals with one particular block of buildings, the solutions and suggestions presented herein are quite applicable on other objects of the same type.</p><p>This thesis is intended to be used as a guideline for energy-preserving projects in general, with an eye to buildings erected during the Swedish “million-programme” in the sixties and seventies.</p><p>The paper starts with the acquiring of all necessary blueprints and technical specifications. It then moves on to a thorough description of the buildings in question, and their heating- and ventilation-systems.</p><p>Followed by this the reader is guided through the successive stages of energy-perseverance measures that are available, and possible. Reasoning around the economic factors concerning all measures is also held.</p><p>The paper ends with conclusion, and a discussion concerning the delicate issue of the higher return-temperatures possibly reaching the district-heating plant.</p>

<p>The presence of deposits in the honing grooves in diesel engine cylinder liners can cause a severe increase in the consumption of lubricating oil. These deposits may appear amber in which case they may be referred to as 'liner lacquerer' or be nearly invisible in which case they are often referred to as 'transparent glaze' or 'bore glaze' in the marine sector. The formation of these deposits is believed to be influenced by engine design, engine load, fuel composition and lubricating oil composition. This relationship has, however, not been well understood and little material has been published on this subject. This thesis describes an investigation of this phenomenon. The problem has been approached by studying the composition of deposit samples, studying cases of deposit formation in the field and through experimental work.</p><p>As a result of this work, it is hypothesized that the root cause of the deposit formation is a mismatch between the rate of formation of oil insoluble material on or within the oil film and the oil film dispersing power and exchange rate. A large number of parameters will affect this balance which explains the sliding shift in appearance and composition of 'liner lacquer' and 'bore glaze' and the difficulty in identifying the cause of this problem.</p><p>A combined mass balance and chemical kinetics approach is used to bridge the gap between fundamental deposit theory and tangible engine related parameters. It is thus possible to rationalize the formation of deposits on cylinder liners. This understanding is sufficient to point out which factors should be considered in terms of the prevention of deposit formation and to present a viable hypothesis on the reason for the deposit formation in the engines that have been investigated in the course of this work as summarized in the following paragraph.</p><p>The presence of deposit indicates that the dispersing power and transport rate of the oil film is insufficient to deal with the deposit precursors being formed. This is believed related to extensive low load operation which is associated with both low liner temperatures and low nominal oil consumption in these engines. Low liner temperatures will encourage the formation of insoluble material due to condensation of sulphuric acid precursors, while low oil consumption is believed to indicate low oil film exchange which reduces the transport of matter and also contributes to oil film oxidation by prolonging the exposure to combustion gases.</p>

<p>Frequency and amplitude dependency of velocity distribution and head loss of oscillatory flow in a rectangular duct have been studied experimentally with a model tunnel system.</p><p>Tests were carried out with the duct of both smooth and rough walls. The smooth wall was made of Plexiglas. Sand roughness was used for the rough wall. Velocity, pressure and differential pressure of stationary flow, pure oscillatory flow and combined oscillatory flow were measured. The combined oscillatory flow was classified as oscillation dominant flow, stationary dominant flow, and oscillation-and-stationary balanced flow. Various oscillating frequencies, amplitudes and steady flow percentages were tested for oscillatory flows. The oscillating frequencies tested were varied from 0.01 Hz to 1.00 Hz. Oscillatory amplitude and stationary part were varied from 10 to 100%. Velocity of the flow was measured with a 2D PIV (Particle Image Velocimetry) and a 2D LDV (Laser Doppler Velocimetry) respectively at different test stages. The maximum mainstream velocity was ranged from 0.05 m/s to 1.1 m/s. Data of pressure variations along the tunnel were collected with differential pressure sensors. Flow rate and instant wall pressures at multiple points along the test tunnel were measured simultaneously. The static pressure in the test tunnel was about 1.0 mWC. The differential pressure along the tunnel was less than 20 mmWC per meter.</p><p>Examples of velocity distribution in the test rig from LDV measurement are presented, for both stationary flow and oscillatory flow. The dimensionless velocity distributions of stationary flow are in good agreement with the universal velocity distribution law. Deviations are obvious between the velocity distributions of oscillatory flow and the universal velocity distribution law, when the measured velocity is scaled to dimensionless by friction velocity from Clauser chart. Examples of PIV velocities of different flow regimes are presented in the forms of velocity profile and velocity waveform. Generally, the velocity distributions are in good agreement with the results from LDV, in agreement with the normal turbulent velocity distribution in a duct, if the velocity magnitude is not too small. Dimensionless velocity profiles at various phase angles of the same oscillatory flow regime have quite consistent distribution. The annular effect is observed in some cases. Its occurrence depends on the complex actions of oscillating frequency, amplitude and stationary flow percentage. The velocity waveform confirms the characteristics of mass oscillation of the flow. No significant phase shift is displayed between the velocity waveform of the boundary and centreline in most cases tested. The vertical velocity, which is normal to the mainstream, is quite small and has similar features to the mainstream velocity.</p><p>The velocity profiles got from both LDV and PIV show that the flows in the test tunnel were typical turbulence, with typical velocity distribution of turbulence. No transition between laminar and turbulence is observed even at the turning point of oscillation.</p><p>Pressure variations measured along the tunnel of different flow regimes are presented. The accelerative heads of oscillatory flow are calculated. The friction head losses along the tunnel are evaluated. The dependencies of pressure variation and friction head loss on oscillatory frequency and amplitude are investigated for both pure oscillatory flow and combined oscillatory flow. It is proven that the friction head loss of oscillatory flow increases along with the increase of frequency if the mean flow rate is kept constant. The peak friction head loss increases along with the increase of oscillatory amplitude. Comparison of pressure variation and friction head loss between stationary flow and oscillatory flow shows that the friction head loss of unsteady flow is much bigger than that of steady flow. This is in good agreement with the expectancy based on the experimental results of laminar flow. The head loss of pure oscillatory flow was greater than that of the stationary flow for dozens or more times for various flow regimes running at equivalent flow rate. The ratio of head loss of combined oscillatory flow to stationary flow running at equivalent flow rate is smaller than that of pure oscillatory flow to stationary flow, several times to dozen times. In general, the frequency dependency of head loss on oscillatory frequency and amplitude is clear, though the measuring length is only 9 metres and the absolute magnitude of pressure variation is less than 0.20 mWC.</p>

<p>Carbon dioxide (CO₂, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO₂ heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO₂ heat pump systems for combined space heating and hot water heating – so-called integrated CO₂ heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems..</p>

<p>This thesis focuses on three main areas within the field of SOFC/GT-technology:</p><p>• Development of a dynamic SOFC/GT model</p><p>• Model calibration and sensitivity study</p><p>• Assessment of the dynamic properties of a SOFC/GT power plant</p><p>The SOFC/GT model developed in this thesis describes a pressurised tubular Siemens Westinghouse-type SOFC, which is integrated in a gas turbine cycle. The process further includes a plate-fin recuperator for stack air preheating, a prereformer, an anode exhaust gas recycling loop for steam/carbon-ratio control, an afterburner and a shell-tube heat exchanger for air preheating. The fuel cell tube, the recuperator and the shell-tube heat exchanger are spatially distributed models. The SOFC model is further thermally integrated with the prereformer. The compressor and turbine models are based on performance maps as a general representation of the characteristics. In addition, a shaft model which incorporates moment of inertia is included to account for gas turbine transients.</p><p>The SOFC model is calibrated against experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC. The agreement between the model and the experimental results is good. The sensitivity study revealed that the degree of prereforming is of great importance with respect to the axial temperature distribution of the fuel cell.</p><p>Types of malfunctions are discussed prior to the dynamic behaviour study. The dynamic study of the SOFC/GT process is performed by simulating small and large load changes according to three different strategies;</p><p>• Load change at constant mean fuel cell temperature</p><p>• Load change at constant turbine inlet temperature</p><p>• Load change at constant shaft speed</p><p>Of these three strategies, the constant mean fuel cell temperature strategy appears to be the most rapid load change method. Furthermore, this strategy implies the lowest degree of thermal cycling, the smoothest fuel cell temperature distribution and the lowest current density at part-load. Thus, this strategy represents the overall lowest risk with respect to system malfunctions and degradation. In addition, the constant mean fuel cell temperature strategy facilitates high efficiency part-load operation. The constant turbine inlet temperature strategy proved to lead to unstable operation at low load, and thus it is considered to be the least adequate method for load change. For both the constant mean fuel cell temperature strategy and the constant TIT strategy, surge might be a problem for very large load reductions. The slowest response to load changes was found for the constant shaft speed strategy. Furthermore, this strategy leads to very low fuel cell temperatures at low loads. This in combination with a possible higher degradation rate makes the constant shaft speed strategy unsuited for large load variations. Nevertheless, operation at constant shaft speed may be facilitated by air bypass, VIGV or compressor blow off.</p> / Paper I is published with kind permission of Elsevier, Sciencedirect.com

The presence of deposits in the honing grooves in diesel engine cylinder liners can cause a severe increase in the consumption of lubricating oil. These deposits may appear amber in which case they may be referred to as 'liner lacquerer' or be nearly invisible in which case they are often referred to as 'transparent glaze' or 'bore glaze' in the marine sector. The formation of these deposits is believed to be influenced by engine design, engine load, fuel composition and lubricating oil composition. This relationship has, however, not been well understood and little material has been published on this subject. This thesis describes an investigation of this phenomenon. The problem has been approached by studying the composition of deposit samples, studying cases of deposit formation in the field and through experimental work. As a result of this work, it is hypothesized that the root cause of the deposit formation is a mismatch between the rate of formation of oil insoluble material on or within the oil film and the oil film dispersing power and exchange rate. A large number of parameters will affect this balance which explains the sliding shift in appearance and composition of 'liner lacquer' and 'bore glaze' and the difficulty in identifying the cause of this problem. A combined mass balance and chemical kinetics approach is used to bridge the gap between fundamental deposit theory and tangible engine related parameters. It is thus possible to rationalize the formation of deposits on cylinder liners. This understanding is sufficient to point out which factors should be considered in terms of the prevention of deposit formation and to present a viable hypothesis on the reason for the deposit formation in the engines that have been investigated in the course of this work as summarized in the following paragraph. The presence of deposit indicates that the dispersing power and transport rate of the oil film is insufficient to deal with the deposit precursors being formed. This is believed related to extensive low load operation which is associated with both low liner temperatures and low nominal oil consumption in these engines. Low liner temperatures will encourage the formation of insoluble material due to condensation of sulphuric acid precursors, while low oil consumption is believed to indicate low oil film exchange which reduces the transport of matter and also contributes to oil film oxidation by prolonging the exposure to combustion gases.