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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Performance Evaluation of a bench-scale Thermochemical Storage System / Prestandautvärdering av ett termokemiskt energilagringssystem i bänkskala

Seetharaman, Harish Balaji January 2022 (has links)
This thesis is part of a joint thermochemical heat storage (TCS) research project named Neutrons for Heat Storage (NHS), involving three Nordic research institutes. The project isfunded by Nordforsk and KTH Royal Institute of Technology for the project partner KTH. KTH´s objective in the NHS project is to design, build and operate a bench-scale TCS system using strontium chloride (SrCl2) and ammonia (NH3) as a solid-gas reaction system for low temperature heat storage (40-100 ℃). Here, absorption of NH3 into SrCl2⋅NH3 (monoammine) to form SrCl2⋅8NH3 (octaammine) is used for heat release, and desorption (of NH3 from SrCl2⋅8NH3 to form SrCl2⋅NH3) for heat storage. This thesis initially aimed to conduct commissioning, operation and experimental data acquisition, and performance evaluation of the bench-scale TCS system. However, due to various delays in equipment delivery and shortcomings discovered during the project timeline, its objectives were then redefined to partially commission the system with NH3 and carry out the first absorption cycle in one of the reactors. This thesis project was partly a joint project, where Hjörtur Brynjarsson performed various tasks in the overarching NHS project as part of his thesis project, alongside the work described in this report. Brynjarsson’s work involved reviewing and adapting the design of this bench-scale TCS system. For further details about the shortcomings discovered and corresponding design adaptations, readers are referred to Brynjarsson’s report. In this thesis project, to understand the design of the TCS system, background research on the current project and the SrCl2-NH3 reaction pair was conducted. This includes comprehending the evolution of the project carried out by the previous students and project researchers to the current thesis project. Following this, the maximum theoretical volume of composites in the reactor-heat exchanger (R-HEX) was determined. This was found to be 5262 cm3, and the corresponding SrCl2 in the R-HEX is 1631 g for an average salt density in the composite of 0.31g/cm3. Thereupon, a literature review was conducted on the performance evaluation of Thermal energy storage (TES) systems. The final report of International Energy Agency (IEA) Annex 30 (on Applications of TES in the Energy Transition: Benchmarks and Developments) presents numerous Key Performance Indicators (KPIs) relevant to TES systems and are classified into technical, economic, and lifetime performance indicators. These KPIs are used as the basis for the current thesis work and are compared to examples from other metalhalide-NH3 TCS systems. Finally, for the current thesis project, it was decided to focus the KPIs on technical performance indicators, such as energy storage capacity [kJ] and reaction advancement [-]. As one of the main tasks within the project, the data acquisition system (for measuring temperature, pressure, and mass flow rate parameters), as well as the system components and many final connections, were commissioned herein. A data acquisition manual is thus provided for future use. It considers all the data measuring instruments and their respective locations in the system and the data logger. Also, explanations are provided for the calibration of these instruments. As the next main task, a thermal homogeneity test of the reactors (to compare the heat transfer similarity of reactors before the first reaction) was performed, to investigate the underlying assumption that the reactors were identical was valid. After conducting the test, it was found that reactor A had slightly better heat transfer than reactor B. However, this inhomogeneity is not significant enough to affect the system’s overall performance. As the final main task, partial commissioning of the system (i.e., for the first absorption reaction in reactor B) with N2 (as a mock-test to troubleshoot the procedure forNH3) and then with NH3 were carried out. During the partial commissioning of the system using NH3, the NH3 was added in short pressure pulses (between 5-8 bar(a)) with idling between each pulse due to some practical reasons. In addition to this, the absorption reaction was carried out under less than ideal (still not unfavourable) absorption conditions by deliberately setting the heat transfer fluid (HTF) at high temperatures (e.g., at 105, 90, and 65 °C) to avoid a drastic pressure drop in the reactor between each NH3 pulse. At the end of the NH3 commissioning (possible completion of absorption), it was found that 1541 g of NH3 passed through the mass flow meter. The most likely scenario is that 1521 g of NH3 reacted with the SrCl2 salt in the reactor (the rest, 20 g, is in the dead space, comprised of, e.g., the voids in composite, voids in the R-HEX, and the volume in the gas lines). The heat released from the absorption reaction, in this case, is 3774 kJ (or 1.05 kWh), considering all eight ammines. The heat released from the absorption reaction of SrCl2∙NH3 (monoammine) to SrCl2∙8NH3 (octaammine) is 3224 kJ (or 0.89 kWh). The discharge power calculation is excluded here due to the special approach used in this first absorption, with long idling steps, making that irrelevant. In addition, the sustainability aspects of this TCS technology (SrCl2-NH3) used in this project were analyzed. Based on the analysis, it was found that this technology is environmentally friendly, economically feasible, and can aid in social development. Hence, this technology is considered sustainable, and the designed TCS system has an overall positive impact on sustainable development. To conclude, within this project, the designed TCS system was successfully operated for the first absorption in one reactor and is found to meet the design storage capacity (0.89 kWh). As this TCS system was mainly operated for data acquisition, and since the first absorption was performed at less-than ideal conditions, better absorption conditions are recommended for the subsequent cycles, accommodating better temperature and pressure conditions for both absorption and desorption reactions. Finally, evaluation of the system's technical performance at different reaction conditions (pressure, temperature) and optimizing the system for energy and economics are some of the key follow-up tasks for future work that will benefit the system. / Detta exjobbsprojekt är en del av ett forskningsprojekt Neutrons for Heat Storage (NHS), som handlar om termokemisk energilagring (TCS) och genomfördes med hjälp av tre nordiska forskningsinstitut. Projektet finansieras av Nordforsk och KTH Kungliga Tekniska Högskolan för KTH. I NHS-projektet, KTH:s mål är att utforma, bygga och driva ett TCS-system i bänkskala med ett fast-gasreaktionssystem som använder reaktionsparet strontiumklorid (SrCl2) och ammoniak (NH3), för värmelagring vid låg temperatur (t.ex. 40-100 ℃). Här används specifikt absorption av NH3 i SrCl2⋅NH3 (monoammin) till SrCl2⋅8NH3 (oktaammin) för värmeavgivning och desorption av NH3 från SrCl2⋅8NH3 till SrCl2⋅NH3 för värmelagring. Detta projekt syftade inledningsvis till att genomföra driftsättning, drift och insamling av experimentella data samt utvärdering av prestanda för TCS-systemet i bänkskala. På grund av olika förseningar i leveransen av flertal utrustningar och brister som upptäcktes under projektets gång, omdefinierades målen till att ta en partiell driftsättning av systemet med NH3 och genomföra den första absorptionscykeln i en av reaktorerna. Detta exjobbsprojekt var delvis ett gemensamt projekt, där Hjörtur Brynjarsson utförde olika uppgifter i det övergripande NHS-projektet som en del av sitt exjobbsprojekt, parallelt med arbetet som beskrivs i denna rapport. Brynjarsson’s arbete bestod i att granska och anpassa utformningen av denna bänkskala i TCS-system. För ytterligare detaljer om de brister som upptäcktes och motsvarande anpassningar av utformningen hänvisas läsarna till Brynjarsson’s rapport. I detta exjobbsprojekt, för att förstå TCS-systemets utformning, genomfördes bakgrundsforskning om det aktuella NHS projektet och reaktionsparet SrCl2-NH3. Detta innefattar att förstå utvecklingen av NHS projektet från tidigare projekt utförda av studenter och projektforskare för att sammanställa detta exjobbsprojekt. Därefter fastställdes i detta projekt den maximala teoretiska volymen kompositer i reaktor-värmeväxlare enheten (RHEX). Den visade sig vara 5262 cm3 och att motsvarande SrCl2 i R-HEX är 1631 g för en genomsnittlig salttäthet i kompositen på 0,31 g/cm3. Därefter gjordes en litteraturstudie om utvärdering av prestanda för system för termisk energilagring (TES). Slutrapporten om bilaga 30 från International Energy Agency (IEA) (om tillämpningar av TES i energiomställningen: Benchmarks och Utvecklingar) presenterar ett flertal nyckelindikatorer (KPI:er) för prestandaanalys som är relevanta för TES-system och som är klassificerade i tekniska, ekonomiska och livslängdsindikatorer. Dessa KPI:er används som grund för den aktuella exjobben och jämförs med exempel från andra metallhalogenid-NH3- TCS-system. För detta exjobbprojektet beslutades slutligen att fokusera KPI:erna på tekniska prestandaindikatorer, t.ex. energilagringskapacitet [kJ] och reaktionsframsteg [-]. Som en av huvuduppgifterna inom detta projekt togs datainsamlingssystemet (för mätning av temperatur, tryck och massflödesparametrar) samt systemkomponenterna och många slutliga anslutningar i drift här. En användarmanual för datainsamling tillhandahålls därför för framtida användning. Den gäller alla instrument för datamätning och deras respektive placering i systemet samt dataloggern. Dessutom ges här förklaringar till kalibreringen av dessa instrument. Som nästa huvuduppgift utfördes ett test av reaktorernas termiska homogenitet (för att jämföra reaktorernas likhet i värmeöverföring före den första reaktionen), för att undersöka om det underliggande antagandet att reaktorerna var identiska var giltigt. Efter att ha utfört testet konstaterades det att reaktor A hade en något bättre värmeöverföring än reaktor B. Denna inhomogenitet är dock inte tillräckligt betydande för att påverka systemets totala prestanda. Som sista huvuduppgift genomfördes en partielldriftsättning av systemet (dvs. för den första absorptionsreaktionen i reaktor B) med N2 (som ett simuleringstest för att felsöka förfarandet för NH3) och sedan med NH3. Under den partiella idrifttagningen av systemet med NH3 tillsattes NH3 i korta tryckpulser (mellan 5-8 bar(a)) med tomgång mellan varje puls av praktiska skäl. Dessutom utfördes absorptionsreaktionen under mindre än ideala (men ändå inte ogynnsamma) absorptionsförhållanden genom att värmeöverföringsvätskan medvetet ställdes in på höga temperaturer (t.ex. 105, 90 och 65 °C) för att undvika en drastisk tryckminskning i reaktorn mellan varje NH3-puls. I slutet av NH3-installationen (eventuellt avslutad absorption) konstaterades att 1541 g NH3 passerade genom massflödesmätaren. Det mest sannolika scenariot är att 1521 g NH3 reagerade med SrCl2-saltet i reaktorn (resten dvs., 20 g, finns i det döda utrymmet, som t.ex.består av hålrummen i kompositen, hålrummen i R-HEX och volymen i gasledningarna). Den värme som frigörs från absorptionsreaktionen är i detta fall 3774 kJ (eller 1,05 kWh), om man beaktar alla åtta aminer. Den värme som frigörs från absorptionsreaktionen av SrCl2∙NH3 (monoammin) till SrCl2∙8NH3 (oktaammin) är 3224 kJ (eller 0,89 kWh). Beräkningen av utmatningseffekten är utesluten här på grund av det speciella tillvägagångssätt som används vid denna första absorption, med långa tomgångssteg, vilket gör att den är irrelevant. Dessutom analyserades hållbarhetsaspekterna av denna TCS-teknik (SrCl2-NH3) som användes i detta projekt. På grundval av analysen konstaterades det att denna teknik är miljövänlig, ekonomiskt genomförbar och kan bidra till social utveckling. Tekniken anses därför vara hållbar och det konstruerade TCS-systemet har en övergripande positiv inverkan på hållbar utveckling. Sammanfattningsvis kan man konstatera att det konstruerade TCS-systemet inom ramen för detta projekt används på ett framgångsrikt sätt för den första absorptionen i en reaktor och att det uppfyller den avsedda lagringskapaciteten (0,89 kWh). Eftersom detta TCS-system huvudsakligen användes för datainsamling och eftersom den första absorptionen utfördes under mindre än ideala förhållanden, rekommenderas bättre absorptionsförhållanden för de efterföljande cyklerna, med bättre temperatur- och tryckförhållanden för både absorptions och desorptionsreaktioner. Slutligen är utvärdering av systemets tekniska prestanda vid olika reaktionsförhållanden (tryck, temperatur) och optimering av systemet med avseende på energi och ekonomi några av de viktigaste uppföljningsuppgifterna för framtida arbete som kommer att gynna systemet.
12

Review and Design Adaptations of a SrCl2-NH3 bench-scale Thermochemical Heat Storage system

Brynjarsson, Hjörtur January 2021 (has links)
Thermochemical heat storage (TCS) is a thermal energy storage (TES) technology used to store thermal energy for later use. TCS can provide heating or cooling services from intermittently available thermal energy, often low grade waste heat. The system studied here stores and releases the energy in the form of chemical energy by utilizing reversible chemical reactions. TCS has potential to reduce greenhouse gas emissions, increase infrastructure system efficiency, lower society-wide energy system costs and by that contribute to sustainable development. This thesis is part of a joint TCS research project named Neutrons for Heat Storage (NHS), involving three research institutes. The project is funded by Nordforsk and KTH Royal Institute of Technology. KTH´s objective in the NHS project is to design, build and operate a bench-scale TCS system using strontium chloride (SrCl2) and ammonia (NH3) as a solid-gas reaction system for low-temperature heat storage (40-80 ℃). Here, absorption of NH3 into SrCl2⋅NH3 (monoammine) to form SrCl2⋅8NH3 (octaammine) is used for heat release, and desorption (of NH3 from SrCl2⋅8NH3 to form SrCl2⋅NH3) for heat storage. Prior to this thesis project, this TCS system, as well as its reactor+heat exchanger (R-HEX) units, were numerically designed at KTH, and the R-HEX units were manufactured. This system is now being built at the laboratory of Applied Thermodynamics and Refrigeration division at the Department of Energy Technology, KTH. The initial system is comprised of a shared storage tank, expansion valve, ammonia meter and an R-HEX (absorption path); and an R-HEX, ammonia meter, gas cooler, compressor, condenser, and the storage tank (desorption path), to accommodate absorption, desorption, and NH3 storage. This thesis was originally planned to include commissioning, operation and experimental data acquisition, and performance evaluation of this system. However, due to various delays and shortcomings discovered at the beginning of the project, its objectives were then redefined to review the system and its components and propose necessary design adaptations of the initially designed (and partially built) system. This thesis project was partly a joint project, where Harish Seetharaman performed various tasks in the overarching NHS project as part of his own thesis project, performed alongside the work described in this report. For various information and results, referring to Harish´s report therefore will be necessary. A literature review of the research into SrCl2-NH3 systems was conducted, with emphasis on performance evaluation, kinetics, and reaction paths. TES performance evaluation is discussed concerning the TCS key performance indicators, with the 2018 IEA's Annex 30 as a guideline and 2013 IRENA´s E17 technology brief as a comparative reference. Much progress and refinement has been made in the 5-year span between the publications of these documents, but some adaptations and interpretations still need to be made to the Annex 30 approach for a good approach to a TCS system of similar nature as the one studied in this report. Review of the latest research on the kinetics and reaction path of the SrCl2-NH3 reaction pair revealed that the 100-year-old single-line-and-path reaction expression is an oversimplification of the actual chemistry. The reaction path seems to be dependent on the kinetics of the reaction, and varies with heating rate, temperature, and pressure. Various literature was found and compared, which show that the reaction enthalpies and entropies are not settled science. This demonstrates the necessity for further research into the SrCl2-NH3 reaction pair before application-scale product design and commercialization can take place. A comprehensive equipment and system review was conducted, whereby multiple issues were found and addressed, that if gone unnoticed, would have caused difficult setbacks for the project.  Consequently, the previous purchased ammonia flow meters and ammonia compressor, were exchanged for new and better suiting equipment. The original ammonia flow meters were undersized due to miscalculations of converting flow units of NLPH (Normal Liters Per Hour) to the project units of g/s, while wrongly using the density of compressed ammonia to convert to g/s, instead of it at the defined normal conditions. Furthermore, these flow meters were of the wrong type, as they had no digital output for data acquisition. The original compressor was also severely undersized, only capable of evacuating 7-14% of the expected maximum desorption flow. This was due to a similar miscalculation during conversion of NLMP (Normal Liters Per Minute) to g/s, as well as an unrequested compressor stroke reduction. New solutions and additional equipment were then required to accommodate the operational limitations discovered in the final chosen equipment and system configuration. These include limiting the compressor inlet pressure to a maximum of 1.1 bar(a); avoiding risk of NH3 condensation at them inlets of the new mass flow meters and compressor; and maintaining the flow meter and compressor inlet temperatures below 40 °C. The pressure limitations required considerable design adaptations. Firstly, an ammonia by-pass is introduced to keep feeding ammonia into the compressor during low desorption flows. The inlet pressure limitation necessitated active pressure management in the form of pressure reduction valves, which were thus introduced. Secondly, the condensation regulation and temperature management required a new approach, as the cooling and condensation temperatures in the original design were too low, causing risks of far too low temperature and pressure in the desorption path, as well as counter-acting simultaneous heating and cooling between the condenser and the storage tank heating sleeve. As a solution, a shunt pump is proposed, where constant cooling water temperature provides condensation on a tight temperature range using an infinite cold wall approach. Along with reviewing the equipment and the system design, new procedures concerning investigating and confirming homogeneous heat transfer properties of the reactors are proposed. Furthermore, improvements are suggested concerning the commissioning of the experimental rig, that include equipment testing with N2-gas and stepwise changes in temperature in sequential cycles to gain a good understanding of the likely behaviors of the system before it is run at the extremes of the operating range. In conclusion, a new and improved process flow diagram, showing all these adaptations, additions, and changes from the original diagram is presented herein as the final key contribution to the overarching NHS-project. This is complemented with an instruction manual, to allow the next researchers a smooth continuation, in terms of the system build, and later commissioning and operation. Finally, some suitable next steps in the project are suggested. These include a conceptualization of descriptive functions for the performance and behavior of the specific system and reactors. These functions are proposed with temperature and pressure as independent variables, as these are two main variables influencing the kinetics of the reaction in the given system. As no experimental data exists yet, the form of the proposed functions is generic. Furthermore, a suggestion is made for a future adaptation for achieving the phase change from NH3(g) to NH3(l) (which is the storage form of ammonia in the system) by deep cooling at the desorption pressure, resulting in only a liquid pump being required to raise the pressure of the NH3(l) in the storage tank. / Termokemisk energilagring (TCS) är en teknik inom termisk energilagring (TES) som används för att lagra termisk energi för senare bruk. TCS kan tillhandahålla värme och kyla från periodvis tillgänglig termisk energi, ofta lågtemperatur spillvärme. Systemet lagrar energin som kemisk energi genom att använda reversibla kemiska reaktioner och massaseparation av reaktions-produkterna. TCS har potential att minska utsläppet av växthusgaser, öka effektiviteten av system i vår infrastruktur, minska energikostnader i samhället och därmed bidra till hållbar utveckling. Detta exjobbsprojekt är en del av ett gemensamt TCS-forskningsprojekt som heter Neutrons for Heat Storage (NHS), där tre forskningsinstitut deltar. Projektet är finansierat av Nordforsk och Kungliga Tekniska Högskolan. KTH:s mål med NHS-projektet är att projektera, bygga, samt driva ett TCSsystem i bänkskala med strontiumklorid (SrCl2) och ammoniak (NH3) som ett fast-gasreaktionssystem för lågtemperaturvärmelagring (40-80 ℃). Här används absorption av NH3 till SrCl2⋅NH3 (monoammin) för att bilda SrCl2⋅8NH3 (oktaammin) för värmeurladdning och desorption (av NH3 från SrCl2⋅NH3 till SrCl2⋅NH3) för värmelagring. Innan detta exjobbsprojekt började hade detta TCS-system, samt systemets reaktor+värmeväxlare (R-HEX) enheter varit numeriskt projekterad vid KTH, och R-HEX-enheterna hade redan tillverkats. Detta system byggs nu på laboratoriet för Avdelningen för tillämpad termodynamik och kylning vid Institutionen för Energiteknik, KTH. Det initiala systemet består av en gemensam lagringstank, expansionsventil, ammoniakmätare, och en R-HEX (systemets absorptionssida) och en R-HEX, ammoniakmätare, gaskylare, kompressor, en kondensor, och en gemensamma lagringstanken (desorptionssidan), for att rymma absorption, desorption (samtidigt) och NH3-lagring. Exjobbsprojektet var ursprungligen planerat att inkludera driftsättning, drift och experimentdatainsamling samt utvärdering av systemet. På grund av olika förseningar och brister som upptäcktes i projektet, omdefinierades projektets mål och består nu av att granska systemet och, samt att föreslå nödvändiga designanpassningar av det ursprungligen konstruerade systemet och dess komponenter. Projektet var delvis ett gemensamt arbete, där Harish Seetharaman utförde olika uppgifter i det övergripande NHS projektet som en del av sitt eget exjobbssprojekt. För olika uppgifter och resultat kommer det därför att vara nödvändigt att hänvisa till Harishs rapport. Litteraturstudié av forskningen kring SrCl2-NH3 system genomfördes, med betoning på prestandautvärdering, kinetik och reaktionsvägar. Prestandautvärdering av TES system diskuteras angående TCS-nyckelindikatorer, med 2018 års IEA:s Annex 30 som riktlinje och IRENA:s E17 Teknologi-sammandrag från 2013 som en referens. Många framsteg och förbättringar har gjorts under femårsperioden mellan dessa publikationer, men vissa anpassningar och tolkningar måste fortfarande härledas till metoderna i Annex 30 för att få ett bra förhållningssätt till ett TCS-system av liknande karaktär som det som studeras i detta projekt. Granskning av den senaste forskningen avseende reaktionskinetik och reaktionsvägar för SrCl2-NH3 reaktionsparet visade att det hundraåriga enkellinje-och-reaktionsväg-formuleringen är en förenkling av den faktiska kemin. Reaktionsvägen verkar beroende av reaktionens kinetik och varierar med uppvärmnings-takten, temperaturen och även trycket. Olika litteratur jämfördes som visar att reaktionsentalpierna och entropierna inte är fastställd vetenskap. Detta visar behovet av ytterligare forskning avseende SrCl2-NH3 innan produktdesign och kommersialisering i applikations-skala kan utföras. En omfattande granskning av systemet och dess komponenter genomfördes, där flera problem hittades och åtgärdades. Om dessa problem hade gått obemärkt förbi skulle det ha orsakat svåra bakslag för projektet. Följaktligen byttes de tidigare köpta ammoniakflödesmätarna ut till nya och en ammoniakkompressor byttes ut mot en ny, för tillämpningen bättre anpassad. De ursprungliga ammoniak-flödesmätarna var underdimensionerade pga. felberäkningar i omvandling av flödesenheter för NLPH (normal liter per timme) till projektenheterna g/s. Samtidigt var densiteten av komprimerad ammoniak felaktigt använt för omvandling till g/s, istället för densiteten vid de definierade normala förhållandena; 1 bar (a) och 20 ° C. Dessutom var dessa flödesmätare av fel typ, eftersom de inte hade någon digital utgång för datainsamling. Den ursprungliga kompressorn var också kraftigt underdimensionerad, endast kapabel att evakuera 7-14% av det förväntade maximala desorptionsflödet. Detta berodde på en liknande felberäkning vid konvertering av NLPM (normal liter per minute) till g/s, samt en oönskad kompressorslagsminskning. Nya lösningar och ytterligare utrustning krävdes för att tillgodose de operativa begränsningar som upptäcktes i den slutgiltigt valda utrustningen och systemutformningen. Dessa inkluderar: begränsa kompressorns inloppstryck till maximalt 1,1 bar(a); undvika risk för NH3 kondens i de nya massflödesmätarna och kompressorn; samt bibehålla flödesmätarens och kompressorns inloppstemperaturer under 40 °C. Tryckbegränsningarna krävde omfattande projekteringsanpassningar. För det första införs en ammoniak-by-pass för att fortsätta mata ammoniak till kompressorn under låga desorptionsflöden. Inloppstrycksbegränsningen nödvändiggjorde aktiv tryckhantering i form av tryckreduceringsventiler. För det andra krävde kondensregleringen och temperaturhanteringen en ny strategi, eftersom kyl- och kondenseringstemperaturerna i den ursprungliga utformningen var för låga. Detta orsakade risker för alldeles för låg temperatur och tryck på desorptionssidan, samt samtidigt motverkande uppvärmning och kylning av kondensorn och förvaringstankens värmehylsa. Som en lösning föreslås en shunt där konstant kylvattentemperatur ger kondens i ett tätt temperaturintervall med en oändlig kallväggsinriktning. Tillsammans med granskning av utrustningen och systemutformningen föreslås nya tillvägagångssätt för undersökning och bekräftelse av reaktorers förmodade homogena värmeöverförings-egenskaper. Dessutom föreslås förbättringar av idrifttagningen av den experimentella riggen, som inkluderar utrustningstestning med N2-gas och stegvisa temperaturförändringar i sekventiella körningar för att få en god förståelse för systemets troliga beteenden innan det körs i ytterligheterna av systemts arbetsområde. Sammanfattningsvis presenteras ett nytt och förbättrat processflödesdiagram, som visar alla utförda anpassningar, tillägg och ändringar från det ursprungliga diagrammet, som är avhandlingsprojektets huvudbidrag till det övergripande NHS-projektet. Detta kompletteras med en bruksanvisning för att smidigt fasa in kommande forskare avseende systemets konstruktion, driftsättning, och drift. Slutligen föreslås några lämpliga kommande steg i projektet. Dessa inkluderar en konceptualisering av beskrivande funktioner för prestanda och beteende av det specifika systemet och reaktorer. Dessa funktioner föreslås med temperatur och tryck som oberoende variabler, eftersom dessa är två huvudvariabler som påverkar reaktionens kinetik. Eftersom inga experimentella data ännu finns, är formen för de föreslagna funktionerna generisk. Vidare ges förslag om framtida anpassning för att uppnå fasändringen från NH3(g) till NH3(v) (som är lagringsformen för NH3 i systemet) genom djup nedkylning vid desorptionstrycket, vilket resulterar i att endast en vätskepump krävs för att höja trycket för NH3(v) i lagringstanken.
13

Caractérisation des systèmes à deux composantes chez Salmonella enterica sérovar Typhi

Murret-Labarthe, Claudie 04 1900 (has links)
No description available.
14

Realize Configurable and Interoperable TT&C with Commercial Components

Patel, Kirti 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / With explosive growth in the satellite communication market. there is an increasing need for the satellite network service providers to support many satellites with a common Telemetry, Tracking, and Commanding (TT&C) assets. The open bus technology, and Commercial Off The Shelf (COTS) Hardware and Software components, provides an opportunity to build a common IF and baseband systems that will support many satellites with different frequencies and protocols. However, the high frequency front end components of the ground station such as antenna or HPA can not be common due to different gain and polarization requirements of the various communication bands and frequencies. The system architecture presented in this paper offers such system that is interoperable and reconfigurable in near real-time to support multiple frequency and multiple communication protocols.
15

Design And Simulation Of A Traction Control System For An Integrated Active Safety System For Road Vehicles

Oktay, Gorkem 01 December 2008 (has links) (PDF)
Active safety systems for road vehicles make a crucial preventive contribution to road safety. In recent years, technological developments and the increasing demand for road safety have resulted in the integration and cooperation of these individual active safety systems. Traction control system (TCS) is one of these individual systems, which is capable of inhibiting wheel-spin during acceleration of the vehicle on slippery surfaces. In this thesis, design methodology and simulation results of a traction control system for four wheeled road vehicles are presented. The objective of the TCS controller is basically to improve directional stability, steer-ability and acceleration performance of vehicle by controlling the wheel slip during acceleration. In this study, the designed traction control system based on fuzzy logic is composed of an engine torque controller and a slip controller. Reference wheel slip values were estimated from the longitudinal acceleration data of the vehicle. Engine torque controller determines the throttle opening angle corresponding to the desired wheel torque, which is determined by a slip controller to track the reference slip signals. The wheel torques delivered by the engine are compensated by brake torques according to the desired wheel torque determined by the slip controller. Performance of the TCS controller was analyzed through several simulations held in MATLAB/Simulink for different road conditions during straight line acceleration and combined acceleration and steering. For simulations, an 8 DOF nonlinear vehicle model with nonlinear tires and a 2 DOF nonlinear engine model were built.
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Análise crítica de estratégias para redução de consumo energético do processo de destilação extrativa. / Critical analysis of strategies to reduce the energy consumption of the extractive distillation process.

CORDEIRO, Gardênia Marinho. 23 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-23T19:16:15Z No. of bitstreams: 2 GARDÊNIA MARINHO CORDEIRO - TESE PPGEQ 2016..pdf: 4354292 bytes, checksum: 1f9e0bf89dc6a2e1c64d5fa7f2e58a85 (MD5) ANEXO_TESE.pdf: 3069265 bytes, checksum: da63715d85442ba1e5c536dc5ebe121f (MD5) / Made available in DSpace on 2018-03-23T19:16:15Z (GMT). No. of bitstreams: 2 GARDÊNIA MARINHO CORDEIRO - TESE PPGEQ 2016..pdf: 4354292 bytes, checksum: 1f9e0bf89dc6a2e1c64d5fa7f2e58a85 (MD5) ANEXO_TESE.pdf: 3069265 bytes, checksum: da63715d85442ba1e5c536dc5ebe121f (MD5) Previous issue date: 2016-08-29 / Capes / A intensificação de processos através de colunas de parede dividida (DWC) e acoplamento térmico de duas colunas (TCS) são apontadas na literatura consultada como uma das alternativas mais promissoras para redução do consumo energético do processo de destilação. Especificamente ao processo de destilação extrativa, o uso destas configurações ainda é questionável e não consensual quanto ao seu potencial de redução de custos totais. Neste trabalho, a fim de avaliar rigorosamente a viabilidade de configurações TCS, três abordagens de redução de energia (otimização, integração térmica e acoplamento térmico) são analisadas e concatenadas de modo a reduzir o custo anual total (TAC) e consumo específico de energia (SEC). O uso de um procedimento de otimização baseado no teor de solvente, com garantia de solução ótima global foi eficiente na redução desses custos, uma vez que apresentou menores resultados (de SEC e TAC) em comparação com todos os fluxogramas da literatura analisados. A inclusão de uma integração térmica para pré-aquecer a alimentação do azeótropo com a corrente de reciclo mostrou-se competitiva com o uso do acoplamento térmico. Para estender a avaliação em configurações DWC, considerando a equivalência em termos de estágio de equilíbrio com TCS, é proposto uma estratégia sistemática para obtenção de uma configuração DWC otimizada, em termos operacionais e de design. Um comparativo rigoroso entre DWC e CS (também otimizada) foi realizado e demonstrou a influência do número de estágios das colunas no desempenho dessas configurações. Em relação aos custos energéticos, todas as DWC’s mostraram-se favoráveis, entretanto, o percentual de redução de carga térmica depende de qual CS tomou-se como referencial. Os melhores resultados de TAC foram obtidos para colunas com o número de estágios bem distintos em cada lado da parede, entretanto, essas colunas não superaram os sistemas convencionais otimizados. Economicamente, a decisão sobre o tipo de configuração mais viável para uma aplicação industrial pode ser tomada como base nas estratégias apresentadas, observando o trade-off entre a capacidade de redução energética das DWC’s e os custos do processo das configurações otimizadas. / The process intensification through dividing wall column (DWC) and thermal coupling of two columns (TCS) are noted in the literature consulted as one of the most promising alternatives to reduce energy consumption of the distillation process. Specifically by extractive distillation process, the use of these settings is still questionable and nonconsensual as to its potential to reduce total costs. In this work, in order to assess accurately the feasibility of TCS, three approaches of energy reduction (optimization, thermal and thermal coupling integration) are analysed and concatenated in order to reduce the total annual cost (TAC) and specific energy consumption (SEC). The use of an optimization procedure based on the solvent content, with guaranteed global optimal solution was effective in reducing these costs, since presented smaller results (SEC and TAC) compared to all studies of the literature examined. The inclusion of a thermal integration to preheat the azeotrope with the recycle proved to be competitive with the use of thermal coupling. To extend the assessment in DWC, considering the equivalence in terms of stage of equilibrium with TCS, proposed a systematic strategy for obtaining a DWC configuration optimized in terms of design and operational. A strict comparison between DWC and CS (optimized too) was performed and showed the influence of the number of stages of the columns in the performance of these configurations. In relation to energy costs, all the DWC's were favorable, however, the percentage of reduction of thermal load depends on which CS took as a reference. The best TAC’s results were obtained for columns with distinctive number of stages on each side of the wall, however, these columns do not have overcome the conventional systems optimized. Economically, the decision about the type of configuration more viable for an industrial application can be taken as the basis of the presented strategies, noting the trade-off between the ability of energy reduction of DWC's and the costs of the process of the optimized configurations.
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Intel Integrated Performance Primitives a jejich využití při vývoji aplikací / Intel Integrated Performance Primitives and their use in application development

Machač, Jiří January 2008 (has links)
The aim of the presented work is to demonstrate and evaluate the contribution of computing system SIMD especially units MMX, SSE, SSE2, SSE3, SSSE3 and SSE4 from Intel company, by creation of demostrating applications with using Intel Integrated Performance Primitives library. At first, possibilities of SIMD programming using intrinsic function, vektorization and libraries Intel Integrated Performance Primitives are presented, as next are descibed options of evaluation of particular algorithms. Finally procedure of programing by using Intel Integrated Performance Primitives library are ilustrated.
18

Hodnocení doby života a změn konfokální mikroskopií / Realisation of method for fluorescence lifetime and spectral changes evaluation using advanced confocal microscopy techniques

Rúbal, Radek January 2015 (has links)
Content is focused on fluorescence lifetime imaging techniques. Fluorescence lifetime is computed from data acquired with using of Leica TCS SP8X confocal microscope sequential scanning. Algorithms and software for the computation, imaging and analysis of fluorescence lifetime is presented. Software is allowing both 2D and 3D imaging of fluorescence lifetime. Techniques are used for fluorescence lifetime imaging of mesenchymal cells and fibroblasts tainted with SPIO-Rhodamin complex.
19

Evaluation of Traction Control Systems for an Electric Forklift Truck

Karlsson, Mattias, Johansson, Sebastian January 2021 (has links)
This thesis evaluates different controllers for traction control on an electric forklift truck and has been done in cooperation with Toyota Material Handling Manufacturing Sweden. The need for a traction control system has increased with the introduction of lithium-ion batteries replacing the older lead-acid batteries, reducing the battery weight and therefore the downward force on the driving wheel increasing the risk for slip. The forklift truck was modelled using Simulink and validated by experiment. Different possible control strategies were investigated and three were chosen for implementation in simulation. These were controllers based on Model Following Control, Maximum Transmissible Torque Estimation and Sliding Mode Control. Model Following Control makes use of a nominal model to compare actual wheel speed values with nominal wheel speed values to determine if slip is occurring, Maximum Transmissible Torque Estimation makes use of a closed-loop disturbance observer to compute the maximum transmissible torque possible without inducing slip and using it as a limitation on the input signal, and Sliding Mode Control uses different functions to \say{slide} along a sliding surface to stay around a specific slip value. All three controller types were developed both as speed controlled and torque controlled. All of the controllers could reduce slip heavily in simulation. The Maximum Transmissible Torque Estimation controller reduced slip the most and kept oscillations at a minimum, but was not as responsive as the others to driver commands. The conclusion was that the controller of choice would depend on the working environment of the forklift truck. In a low friction environment where slip is expected to occur often, the Maximum Transmissible Torque Estimation controller is advisable, while the other two would be a better choice for environment with low slip occurrence. The use of torque control, while often better with regards to decreasing slip, could not be advised due to a perceived increase in implementation cost.
20

PhoR, PhoP and MshC: Three essential proteins of Mycobacterium tuberculosis

Loney, Erica 21 August 2014 (has links)
No description available.

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