11 |
Development of an energy management solution for mine compressor systems / Johan Nicolaas du PlessisDu Plessis, Johan Nicolaas January 2010 (has links)
Eskom is under increasing pressure to provide reliable and sustainable electricity. Demand Side
Management (DSM), offers a short– to medium–term solution to this problem. During 2009, the mining
sector consumed approximately 16% of the domestic electricity supplied by Eskom. This made the
mining sector one of the major targets for Eskom–initiated DSM programmes.
The mining industry uses compressed air for a wide variety of applications and production purposes. This
creates many opportunities to reduce electricity consumption and operating costs. Reducing the airsystem
demand may however not result in significant electrical energy savings, unless the compressed–air
supply is accurately managed to meet the reduced demand.
Until recently, compressor control in the mining sector generally consisted of operating the compressors
continuously, regardless of the actual demand for compressed air. Excessive compressed air is blown off
into the atmosphere resulting in energy loss. This usually occurs when the compressors are operated
manually.
A computer–controlled compressor management solution, which optimises the efficiency potential of the
compressed–air supply, is required to obtain significant electrical energy savings. The need for such a
solution was addressed by the development of an energy management solution for mine compressor
systems. This solution is referred to as Energy Management System (EMS) and is capable of starting,
stopping, loading and unloading compressors. In addition to this, compressor output can be controlled to
maintain a desired pressure set–point.
In this study, the development and implementation of EMS on ten different mine compressor systems is
presented. Automatic compressor capacity control was implemented, while an operator manually initiated
compressor starting; stopping; loading and unloading, according to EMS control schedules.
Centralised compressor control is one of the main advantages offered by EMS, especially for
compressed–air systems with multiple compressor systems at different geographic locations. EMS
facilitated effective and sustainable electrical energy reductions for all these compressed–air systems. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011.
|
12 |
Development of an energy management solution for mine compressor systems / Johan Nicolaas du PlessisDu Plessis, Johan Nicolaas January 2010 (has links)
Eskom is under increasing pressure to provide reliable and sustainable electricity. Demand Side
Management (DSM), offers a short– to medium–term solution to this problem. During 2009, the mining
sector consumed approximately 16% of the domestic electricity supplied by Eskom. This made the
mining sector one of the major targets for Eskom–initiated DSM programmes.
The mining industry uses compressed air for a wide variety of applications and production purposes. This
creates many opportunities to reduce electricity consumption and operating costs. Reducing the airsystem
demand may however not result in significant electrical energy savings, unless the compressed–air
supply is accurately managed to meet the reduced demand.
Until recently, compressor control in the mining sector generally consisted of operating the compressors
continuously, regardless of the actual demand for compressed air. Excessive compressed air is blown off
into the atmosphere resulting in energy loss. This usually occurs when the compressors are operated
manually.
A computer–controlled compressor management solution, which optimises the efficiency potential of the
compressed–air supply, is required to obtain significant electrical energy savings. The need for such a
solution was addressed by the development of an energy management solution for mine compressor
systems. This solution is referred to as Energy Management System (EMS) and is capable of starting,
stopping, loading and unloading compressors. In addition to this, compressor output can be controlled to
maintain a desired pressure set–point.
In this study, the development and implementation of EMS on ten different mine compressor systems is
presented. Automatic compressor capacity control was implemented, while an operator manually initiated
compressor starting; stopping; loading and unloading, according to EMS control schedules.
Centralised compressor control is one of the main advantages offered by EMS, especially for
compressed–air systems with multiple compressor systems at different geographic locations. EMS
facilitated effective and sustainable electrical energy reductions for all these compressed–air systems. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011.
|
13 |
Vokalproduktion : Kärnan i musiken / Vocal Production : The main core in musicAndersson, Markus January 2020 (has links)
Syftet med arbetet har varit att nå utvecklad kännedom inom vokalproduktion genom att undersöka vad som kan göras för att höja kvaliteten på sången i en musikproduktion. En viktig fråga har varit om fokus, för att nå ett gott resultat, framförallt vikten på inspelningen av sången eller om mycket också kan göras genom efterbearbetning för att nå ett gott resultat. Under detta projekt har jag valt att arbeta med tre produktioner där min egen sång står i centrum. Dessa har lite olika stilar på sången och jag har valt just dessa för att utmana mig själv och se hur de olika sångerna ska poleras för att få sin plats i en slutgiltig produktion. För produktionen har jag använt mig av Logic Pro X som DAW. Resultatet är tre produktioner där jag bedömer att sången genom de produktionsmetoder som tillämpats har blivit betydligt bättre jämfört med tidigare produktioner som jag har genomfört. Bland de metoder och tekniker som jag tillämpat ingår programmet Melodyne som jag använt för att höja sångens kvalitet genom att sången blivit tightare och renare. Även equalizer ochkompressor har bidragit till att få sången att låta jämn. En viktig slutsats är att all sång, trots omfattande bearbetning med effektiva redigeringsverktyg, skulle behöva sjungas om innan de aktuella låtarna kan publiceras genom ett eventuellt släpp. / The aim of the work has been to gain advanced knowledge in vocal production by investigating different methods to raise the quality of the vocal parts in a music production. An important question has been whether the focus, to achieve a good result, mainly has to be the recording of the song or whether much can be done through post-processing in order to achieve a good result. During this project I have chosen to work with three productions where I sing the vocal parts myself. These have slightly different styles on the song and I have chosen just these to challenge myself and how to edit and produce the vocal part for at good result in the final production. For the production I have used Logic Pro X as DAW. The result is three productions where the production methods used, from my view, clearly has contributed to a better result compared with productions that I previously have performed. The methods and techniques that I have applied include the Melodyne software, which I have used to improve the quality of the song by making the song tighter and cleaner. Also equalizer and compressor have been used to improve the sound quality. However, it is important to conclude that the vocal parts in the productions, despite extensive processing with efficient editing tools, would need to be re-recorded before the songs can be published.
|
14 |
Säker start av Kalmare Nyckel´s Nohab-Motor : Styrsystem för indikering av ventiler, pumpar och kompressorer för spärr av startknapp.Strand, Jonathan, Yllenius, Robin January 2021 (has links)
På fartyget M/S Calmare Nyckel finns en NOHAB-dieselmotor installerad ombord som används förundervisning på sjöfartshögskolan i Kalmar. Projektet har undersökt om det är möjligt att görauppstart av motorn säkrare för både handledare och elever. Arbetet har tagit fram ett nytt elskåp och styrsystem enligt DNV-Standard för att försäkra sig om att motorn inte går att starta utan att alla kringsystem som behövs är igång. I framtiden finns det även möjlighet att utveckla nya systemet om det skulle vara önskvärt. Arbetet har även konstaterat att det saknas ordentliga handlingar för elritningar och kabeluppmärkning ombord som bör åtgärdas i framtiden. / On the ship M/S Calmare Nyckel there is a NOHAB-Diesel Engine installed that are used foreducational uses on Kalmar Maritime Academy in Kalmar. This project has investigated if it’s possibleto make the startup of the engine safe both for teachers and students.The project has brought a new control cabinet and a new control system according to DNV-Standardto ensure that the engine doesn’t start without any auxiliary system that’s needed is running.In the future, there’s also possible to develop the system if that would be desirable.The project has also found that the lack of proper documents for electrical drawings and cablemarkings onboard should be addressed in the future.
|
15 |
Influence on tip leakage flow in a compressor cascade with plasma actuationWang, Haotian January 2019 (has links)
As one of the key components of aero engines, compressor is required to endure higher pressure, possess higher efficiency and wider operating range. Intensive studies have been made on tip leakage flow and researchers find that by reasonably organizing tip leakage flow, aero engines are more likely to achieve better performance and reliability. Conventional flow controlling methods like casing treatment and micro jet could substantially modify tip leakage flow, unfortunately with a price of additional loss, not to mention the difficulty in manufacturing such structure. Whereas plasma actuation flow control method uses plasma actuators, such equipment is easy to build, responses fast and has a wide excitation bandwidth. This method has become a new trend in internal flow active control field. In this research, a phenomenological model is adopted to simulate DBD plasma actuation in the flow field inside a compressor cascade. The aim is to find out how plasma actuation will influence tip leakage flow. Meanwhile possible means to improve plasma actuation performance are discussed. First of all, numerical simulation of flow inside a compressor cascade without plasma actuation is conducted to validate accuracy of the numerical methodology adopted and then determine one numerical approach that satisfies specific needs sufficiently. Meanwhile, influence of casing movement on tip leakage flow as well as possible mechanism of tip leakage vortex core generation is investigated in detail. The results indicate: 1. Generating position of tip leakage vortex moves towards leading edge with increasing moving speed of shroud. 2. As shroud moving speed increases, trajectory of tip leakage vortex moves away from suction side of blade and closely towards shroud. 3. Casing movement tends to transform tip leakage vortex from circular to oval shape due to circumferential shearing. 4. Casing movement has little influence on total pressure field concerning absolute pressure value. While total pressure loss does reduce slightly with increasing moving speed of shroud. 5.Vorticity transport from tip clearance into passage may be contributing significantly to generation of tip leakage vortex inner core. Secondly, a simplified model of DBD plasma actuation based on literature [1] is derived and applied through UDF function of commercial software Fluent into the flow field. Different actuation positions, voltages and frequencies are applied in simulation and compared. After that casing movement is included. Main conclusions are as follow: 6. Plasma actuation shows significant suppressing effect on tip leakage vortex on both size, trajectory and strength. 7. The suppressing effect on tip leakage vortex grows stronger as actuator moves towards leading edge. 8. Increasing actuation voltage results in stronger suppressing effect on tip leakage vortex. 9. Plasma actuation can effectively improve total pressure loss situation near shroud region with increasing actuation power. 10. Increasing actuation frequency results in stronger suppressing effect on tip leakage vortex as well. Additionally, frequency performs slightly better than voltage. 11. Casing movement tends to weaken suppressing effect of tip leakage vortex by plasma actuation. More actuation power is needed to achieve sufficient suppressing effect in real compressors. / Som en av de viktigaste komponenterna i flygmotorer krävs det att kompressorn utsätts för högre tryck, har högre effektivitet och större driftsintervall. Intensiva studier har gjorts om skovlarnas toppspel läckageflöde och man anser att det är mer sannolikt att flygmotorer uppnår bättre prestanda och tillförlitlighet genom att på ett rimligt sätt reglera läckageflödet i toppspelet. Konventionella metoder för reglering av flödet, som behandling av “casing” och mikrojet, skulle kunna ändra läckageflödet avsevärt, men medför tyvärr ytterligare förlust, för att inte tala om svårigheten att tillverka en sådan struktur. Samtidig flödeskontroll med hjälp av plasma aktuatorer som är relativt lätta att bygga, reagerar snabbt och har en bred excitationsbandvid. Denna metod har blivit en ny trend inom det interna flödesaktiva kontrollområdet. I denna forskning antas en modell för att simulera plasmaaktivering av DBD i flödesfältet i en kompressorskaskad. Man försöker ta reda på hur plasmaaktivering påverkar läckageflödet. Möjliga sätt att förbättra effekten av plasmaaktivering diskuteras. För det första genomförs numerisk simulering av flödet i en kompressorskaskad utan plasmaaktivering för att validera noggrannheten i den numeriska metoden. Därefter undersöks i detalj vilken inverkan den relativa rörelsen av ”casing” har på läckageflödet genom toppspelet och mekanismen för toppspelsvirvel analyseras. Resultaten visar: 1. Startposition för läckagevirveln rör sig mot skovelns framkant när man introducerar och ökar den relativa hastigheten för ”casing”. 2. I takt med att den relativa hastigheten ökar, kretsbanan för läckage virveln rör sig bort från skovelns sugsida och närmare mot ”casing”. 3. Den relativa rörelsen tenderar att omvandla virveln från cirkulär till oval form på grund av skjuvkrafter. 4. Den relativa rörelsen av ”casing” påverkar inte det totala tryckfältet när det gäller det absoluta tryckvärdet. Samtidigt som den totala tryckförlusten minskar något med ökad hastighet. 5. Virveltransport från toppspelet till huvudkanalen kan på ett betydande sätt bidra till att skapa virvelns inre kärna. I senare delen av arbetet utvecklas och tillämpas en förenklad modell för plasmaaktivering av DBD baserad på litteratur [1], genom att använda UDF‐funktionen i kommersiell CFD programvara Fluent. Olika aktuatorläge, spänningar och frekvenser prövas i simuleringen och jämförs. De viktigaste slutsatserna är följande: 6. Aktuering av plasma visar en betydande dämpningseffekt på läckagevirveln i toppspelet både va det gäller dess storlek, bana och styrka. 7. Den dämpande effekten på läckagevirveln blir starkare när aktuator monteras närmare skovelns framkant. 8. Ökad aktuatorspänning leder till en starkare dämpande effekt på läckagevirveln. 9. Ökad aktuatorfrekvens leder till starkare dämpningseffekt på läckagevortex också.mDessutom fungerar frekvensen något bättre än spänningen. 10. Den relativa rörelsen av ”casing” försvagar effekten av plasmaaktuering. För att uppnå tillräcklig dämpningseffekt i riktiga kompressorer krävs mer effekt till aktuatorn.
|
16 |
Dataanalys av en ny avfrostningsrutin på en kyl- och frysanläggning : En studie gjord hos Freezing Food Småland Öland ABAusmeel, Erik, Gannholm, Botvid January 2021 (has links)
Den här rapporten handlar om en ändring i livsmedelsföretaget Freezing Food Småland Öland AB:s avfrostningsrutin för deras förångare i frysrummet. Ändringen gick ut på att avfrostningstiden och maxtemperaturen sänktes samt att tiden mellan avfrostningarna nu sker varannan i stället för varje natt. Syftet var att undersöka om ändringen av rutinen hade bidragit till en minskad energiförbrukning i förhållande till innan ändringen gjordes genom att också granska andra faktorer än själva avfrostningen som kunde tänkas påverka energiförbrukningen. Metoden gick ut på att insamla och analysera stora datamängder tillhandahållna av företaget för att sedan reducera dem till hanterbara siffror. Även data för lokala utomhustemperaturer samlades in. Med hjälp av detta beräknades medelvärden för en given tidsperiod för energiförbrukning, lagerhållning och utomhustemperatur. Resultatet visade en sänkning av energiförbrukningen, hur stor andel som berodde på avfrostningens ändrade rutiner lämnade undersökningen obesvarat. Utomhustemperaturen bör ha minskat effektbehovet, samtidigt bör lagerhållningen ökat den. Slutsatsen blev att mer tid behövde passera och en ny undersökning behöver framställas efter att avfrostningsrutinen ändrades för att möjliggöra en säkrare bedömning. / This report is about a change in the food company Freezing Food Småland Öland AB’s defrosting routine for their evaporators in the freezer warehouse. The change was that the defrosting time and maximum temperature were reduced and that the time between defrostings now takes place every other night instead of every night. The aim was to examine whether the change in the routine had contributed to a reduction in energy consumption compared to before the change was made by also examining factors other than defrosting itself that might affect energy consumption. The method was to collect and analyze large amounts of data provided by the company and then reduce them to manageable figures. Data for local outdoor temperatures were also collected. This calculated averages for a given time period for energy consumption, warehousing and outdoor temperature. The results showed a decrease in energy consumption, the proportion due to the change in defrosting procedures left the investigation unanswered. The outdoor temperature should have reduced the power requirement, at the same time the storage should have increased it. It was concluded that more time needed to pass,and a new study needed to be produced after the defrosting routine was changed to allow for a safer assessment.
|
17 |
The Impact of Different Monitoring Levels For Listeners' Ability to Detect Dynamic Range Compression in Popular MusicOlofsson, Joakim January 2023 (has links)
There are many useful guidelines and theories to be found on mixing and mastering. One of these statements is that the monitoring level affects how well one can detect and evaluate the Dynamic Range Compression (DRC) when mixing. However, some of the sources that support this idea are contradictory as to whether a low or high monitoring level is better for this purpose. No previous research on this subject has been found, even though monitoring levels are presumed to be essential for the mixing and mastering engineer. The aim of the study was to investigate if the monitoring level will affect the listeners’ detection threshold for DRC when applied to a vocal track. For this, one higher and one lower monitoring level was chosen, and a simple up-down method was used to obtain the X50 in each monitoring condition, in which these were compared. The results indicate that the monitoring level does not affect the listeners’ threshold of detection for DRC. Moreover, it can be stated that the monitoring level in which the participants had the most habit of working in did not affect the result either. This research can be used to take more informed decisions regarding monitoring levels and to revisit some previous observations.
|
18 |
RANS & WMLES Simulations of Compressor Corner SeparationPoulain, Arthur January 2019 (has links)
In axial compressor, corner separation phenomenon can occur between the blade surface and the hub. This leads to high total pressure losses, blockage and may worsen to surge. Various studies on NACA65-009 blade were previously performed experimentally and numerically to predict the corner separation. The LMFA showed that RANS simulations tend to overestimate it while the Wall-Resolved LES (WRLES) was able to well capture it. The conclusions drawn on RANS are validated here with another solver software. An extensive parametric study is performed on RANS which highlights the good performance of two non-linear turbulence models k − ω Wilcox QCR and EARSM k − kl for for predicting the topology and the intensity of corner separation. They are however very dependent on the mesh and the numerics. A Wall-Modeled LES (WMLES) is then computed. It reproduces well the topology of the separation given by the experiments and predicts similar anisotropy to the WRLES. Nevertheless it shows high sensitivity to the level of turbulence close to the endwall and the boundary layer profile of the upstream flow. Finally, this confirms that the WMLES is a promising alternative to the WRLES in order to study the corner separation on more costly geometries (several blades for instance). / I axiell kompressor kan hörnseparationsfenomen uppstå mellan bladytan och navet. Konsekvenserna är stora totala tryckförluster och kompressor blockering. Olika studier på NACA65-009 bladet utfördes tidigare experimentellt och numeriskt för att förutsäga hörnseparationen. LMFA visade att RANS simuleringar tenderar att överskatta den hörnseparationen medan Vägg-Löst LES (WRLES på engelska) kunde fånga bra den. Slutsatserna som dras om RANS valideras här med en annan lösningsprogramvara. En omfattande parametrisk studie utförs på RANS som belyserde goda prestandan för två icke-linjära turbulensmodeller k − ω Wilcox QCRoch EARSM k − kl för att förutsäga topologin och intensiteten för hörnseparation. Dock är de mycket beroende av nät och numerik. En Vägg-Modell LES (WMLES på engelska) beräknas sedan. Det reproducerar väl topologin för separationen som ges av experimenten och förutsäger liknande anisotropi som WRLES. Dock visar det hög känslighet för turbulensnivån nära ändväggen och gränsskiktsprofilen för uppströmsflödet. Slutligen bekräftar detta att WMLES är ett lovande alternativ till WRLES för att studera hörnseparationen på dyrare geometrier (till exempelflera blad).
|
19 |
Development of an oil free turbo compressor for mobile fuel cell applications – challenges and resultsFröhlich, Patrik 25 November 2019 (has links)
The compressor for air supply to the fuel cell stack is a critical component of the balance of plant, especially for mobile applications. The main requirements of the compressor are the performance regarding pressure ratio, mass flow and efficiency at minimal size and weight. The turbo compressor technology is ideally suited to cope with these requirements. The lifetime requirement and the necessity of oil and particle free air supply advised to employ air bearings. The fuel cell air supply requirements are in conflict with the turbo compressor pressure ratio and mass flow characteristics. Possible solutions and their impact onto compressor design and fuel cell operation are described in this paper. The chosen system design approach considering all design aspects and its interactions during the design phase is beneficial in order to achieve the most lightweight and efficient air supply system for fuel cells. Experimental validation of an air bearing turbo compressor for a 100 kW fuel cell stack on an aerodynamic test rig verifies the predicted performance.
|
20 |
Techno‐economic analysis of a hydrogen pipeline infrastructureNorberg, Johannes January 2024 (has links)
With hydrogen playing a major role for reaching net zero emissions, the main challenge will be the integration of the energy carrier. This includes solutions for storage, production and transportation of the gas. Alternatives for hydrogen transportation could include either train, truck or boat. However, the current most economical and promising technology is pipeline transmission, especially in northern Sweden, with new green projects suchas H2 Green Steel and HYBRIT. They will create a market that needs a hydrogen infrastructure, which hydrogen pipelines could provide. This thesis will cover a techno-economic evaluation of hydrogen piping, involving material, compressor technology and pipeline dimensions. Hydrogen is briefy covered in its main production, applications and transportation options in the beginning of the thesis. This will ultimately converge into a in-depth analysis of hydrogen piping. This analysis includes alternatives for compressors, materials for pipes and main technical challenges. The gathered information concluded that hydrogen transport will most likely use either reciprocating or centrifugal compressors. Centrifugal compressors have the advantage of managing high gas flows, and the reciprocating compressors are mature and have a high capacity for pressure. For materials, embrittlement is the main challenge when transporting hydrogen gas, and standard ASME B31.12 provides current directions for hydrogen piping. A yield strength of 30% is required in the material, to compensate for hydrogen’s attributes. Generally the higher the strength of the material, the higher the risk of embrittlement and pipe damage. Careful selection has to be made in termsof micro structure, strength and coating to minimise leakage. To realise how hydrogen infrastructure could be constructed, three scenarios where created. These scenarios were based on assumptions and article values to best illustrate future hydrogen transportation. Main scenario settings include a pressure ratio of Pratio < 1.5, and length between compressors of maximum 135km. These assumptions help keep fnal results within a reasonable dimensions. The results from the initial calculations yielded an optimal diameter of 0.35m for Scenario A. At this diameter, an operational pressure of 85 bar and one compressor with 40 MWe optimally transported the gas. With compressor cost decreasing as pipe cost increases, a trade of in price is found at the lowest cost. For a higher diameter, optimising fow resulted in a lower OP, and a lower power consumption for compressors. Scenario B resulted in a diameter of 0.3 m, an OP of 150 bar, four compressors for a total of 405 km pipes. The lowest possible diameter yielded the lowest cost. If other factors are to be considered, a larger diameter could be used for a lower OP, thus reducing stress on material and compressors. Comparison with electricity (Scenario C) mainly resulted in a higher CAPEX for Hydrogen infrastructure, but a lower transmission cost per MWe per km. This concludes that hydrogen piping is better suited for carrying the energy, due to the large decrease in transfer cost. Finally, for material selection low strength carbonsteels are currently the best alternative for transportation of hydrogen. This is due to its commercial use, good composition, high strength and availability.
|
Page generated in 0.0724 seconds