No description available.

<p>Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.</p><p>The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.<strong></strong></p><p>The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.</p><p> </p><p> </p>

Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system. The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios. The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.

<p>This licentiate thesis proposes and analyzes three carbon dioxide novel cycles, namely: the carbon dioxide transcritical power cycle, the carbon dioxide Brayton cycle and the carbon dioxide cooling and power combined cycle. Due to the different characteristics of each cycle, the three cycles are suitable for different applications. The CO₂ transcritical power cycle is suitable for harvesting energy from low-grade heat sources, near which a low temperature heat sink is accessible. The CO₂Brayton cycle is suitable for harvesting the energy from relatively high-grade heat sources when there is no low temperature heat sink available. The CO₂cooling and power combined cycle is suitable for applications, where both power and cooling are needed (e.g. automobile applications, in which the cycle can utilize the energy in the engine exhaust gasses to produce power and provide cooling/heating to the mobile compartment room at the same time).</p><p>Several models have been developed using the software known as Engineering Equation Solver (EES)¹for both cycle analysis and computer aided heat exchanger design. Different cycle working conditions have been simulated and different working parameters’ influence on the cycle performance has been explained. In addition, Refprop 7.0² is used for calculating the working fluid properties and the CFD tool Femlab has been employed to investigate the particular phenomena influencing the heat exchanger performance.</p>

<p>Following licentiate thesis is a summary of the advances made within the research project - Micro- and nano structured surfaces for enhanced boiling heat transfer – which is a collaboration effort between the Divi-sion of Applied Thermodynamics and Refrigeration and the Division of Materials Chemistry at the Royal Institute of Technology (KTH).</p><p>The main objectives with this research project has been to: <i>develop</i> <i>methods for producing highly efficient boiling surfaces with well defined</i> <i>micro- and nano-structured porous surfaces by the use of micro- a</i>nd <i>nano-manufacturing techniques</i>. This objective has been achieved and the result is a novel micro-porous surface structure comprising dendritically ordered nano-particles of cop-per. The structure was fabricated by a high-current-density electrode-position process, in which the evolution of hydrogen bubbles serve as a dynamic masking template to the growth of the dendritic copper struc-ture. Important variables were identified that affect the production of the structure and its features, such as surface orientation during electrode-position, pressure and temperature of electrolyte, and a final heat treat-ment of the surface under reduced atmosphere, all of which have previ-ously not been reported on.</p><p>Experimental tests have been conducted in a widely used refrigerant, R134a, where the micro-porous structure was shown to enhance the boiling performance of a copper surface over 15 times compared to a regular copper surface. The boiling characteristics of the structure were found to be dependent on controllable surface characteristics. The re-markably good boiling performance of the novel micro-porous en-hancement structure has been attributed to its high porosity ( ~94%), a dendritically formed and exceptionally large surface area, and to a high density of well suited vapor escape channels (>50 per mm2).</p><p>A patent application, intended to protect the enhancement structure and its fabrication method, was submitted to the Swedish patent authorities (PRV) on March 1st, 2006.</p>

Syftet med den här studien är att studera vindprofiler och klassificera Low Level Jets (LLJ) och även analysera den termiska vinden över Östergarnsholm. Östergarnsholm är en liten ö som ligger 4 kilometer öster om Gotland. Viseringar och sonderingar från åren 1995 till 2001 samt år 2003 har använts. Det kriteriet som har använts för att klassificera LLJs är att det ska finnas ett vindhastighetsmaximum under 500 meters höjd. De undersökta orsakerna till uppkomsten av en LLJ är sjöbris, tröghetssvängning och termisk vind. För att kunna ta ut LLJs orsakade av sjöbris har vindprofiler över hela dygn använts. Vindens vridning vid marken, under dagen, jämfört med den överlagrade vindens riktning vid 2000 meters höjd har undersökts. LLJs som uppkommit på grund av tröghetssvängning har analyserats. Metoden för tröghetssvängning bygger på att analysera den geostrofiska vindens hastighet och vindriktning för att sedan kunna räkna ut hur vinden har blåst och var en eventuell LLJ skulle kunna bildas. Här har vindriktningar mellan 20º – 220º använts eftersom det medför att vinden då blåser från havet. Resterande vindriktningar medför att vinden har blåst över Gotland vilket resulterar i att en eventuell tröghetssvängning skulle störas och en LLJ skulle försvinna innan den når Östergarnsholm. Vindhastigeter och vindriktningar har jämförts med teoretiskt uträknade värden från tryckmätningar. Från alla 245 viseringar fanns 103 vindprofiler med LLJs. Utav dessa var 27 stycken, under 12 dygn, orsakade av sjöbris. Hur många LLJs som bildats av tröghetssvängning är oklart. Detta eftersom olika resultat erhålles beroende på om vindhastigheter och vindriktningar tas från viseringarna eller är beräknade från tryckmätningar, samt om beräkningarna av transporttiden sker med raka eller krökta trajektorier. Totalt hittades 9 LLJs som orsakats av tröghetssvängning. Metoden som använts för att analysera tröghetssvängning ger förmodligen bättre resultat över land än över hav. Detta eftersom det är svårt att mäta de exakta vindförhållandena längs luftens transport över hav. Den geostrofiska vindens ändring med höjden över ön, det vill säga den termiska vinden, har analyserats genom att undersöka alla vindprofiler, även de utan LLJs. Dessa har jämförts med den geostrofiska vinden beräknad från tryckmätningar, som representerar vinden vid marken, för att se om det uppkommer termiska vindar över Östergarnsholm. En LLJ som orsakats av termisk vind uppkommer när den geostrofiska vinden avtar med höjden, det vill säga vid negativ termisk vind. Antalet fall där den geostrofiska vinden avtar med höjden och där vinden är konstant med höjden var ungefär lika många. Däremot fanns något fler fall där den geostrofiska vinden ökade med höjden, dessa uppgick även till högre hastigheter än när vinden avtog med höjden. Det finns inget samband för vindvridningen med höjden då det förekommer LLJs på grund av termisk vind. Däremot finns ett tydligt samband mellan den negativa termiska vindens u- och v-komponent och den geostrofiska vindens u- respektive v-komponent. I båda fallen så tenderar vinden att gå mot noll med höjden. Totalt hittades 41 LLJs som var orsakade av termisk vind. Vid ungefär 50% av alla vindprofiler, både när den geostrofiska vinden avtog och ökade med höjden, var den termiska vindens nord-sydliga komposant positiv och den ost-västliga komposanten negativ. Detta ger att den varmare luften finns i nordost. / The aim of this study is to classify Low Level Jets (LLJ) and analyze the thermal wind over Östergarnsholm. Östergarnsholm is a small island that is situated 4 kilometres east of Gotland in the Baltic Sea. Pibal trackings and soundings from 1995 to 2001 and 2003 have been used in the study. The criteria that have been used to classify the LLJs is that there must be a maximum of the wind speed below 500 meters. Wind profiles from a specific day have been used to determine if the LLJs is caused by sea breeze. The shift of wind direction at ground level, during the day, compared to the geostrophic wind at 2000 meters has been analyzed. LLJs caused by internal oscillation have been analyzed. In the used method the geostrophic wind speed and wind direction have been analyzed to determine how the wind has blown and where a LLJ possibly could be formed. Only wind directions between 20º and 220º have been used to avoid that the wind should have passed Gotland. If the winds have passed Gotland the internal oscillation has been disturbed and no LLJ can appear. Measured wind speeds and directions have been compared to theoretical values from pressure measurements. 103 wind profiles with LLJs were found from all pibal trackings. In 27 of these pibal trackings, from 12 days, were LLJs caused by sea breeze. It is difficult to say how many LLJs that are caused by an internal oscillation. This due to the different results obtained when using wind speeds and wind directions from pibal trackings or pressure measurements. Also using straight line trajectories or trajectories following the isobars gives different results. Totally 9 LLJs were found, caused by an internal oscillation. Probably this way of analyze the internal oscillations is a better method for measurements over land than over sea. This due to the difficulties in measuring the exact wind speed and wind direction over the whole traveling distance over sea. The thermal wind over the island has been analyzed by studying all pibal trackings, even those without LLJs. The pibal trackings have been compared to the geostrophic wind calculated from pressure measurements to determine if thermal winds occur over Östergarnsholm. A LLJ caused by thermal wind occur when the geostrophic wind decreese with height, i.e. negative thermal wind. There was no difference in the amount of negative thermal winds and cases with no thermal wind. There were a few more positive thermal winds and they had higher wind speeds than the negative ones. There is no connection in the shift of wind direction when there is a LLJ caused by thermal wind. But there is a significant connection between the u- and v-component of the negative thermal winds and the u- and v-component of the geostrophic wind. In both cases the geostrophic wind tends to decreese towards zero with height. 41 of all LLJs were caused by thermal winds. About 50% of both negative and positive thermal winds have a positive v-component and a negative u-component. This means that the warmer region is in the north east.

Idag spenderas en stor del av vår tid inomhus, det ställer krav på inomhusluften.  Koldioxid och andra föroreningar, som stannar i luften vid dåligt ventilerade  lokaler, påverkar negativt och är bevisat att påverka prestationen och produktiviteten  hos människor i specifika uppgifter. Idag läggs mycket fokus på miljösmarta  lösningar och effektiviseringar, men ibland glöms inomhusklimatet bort. För att  människor ska få en behaglig upplevelse av inomhusklimatet krävs  kvalité på inomhusluften men också på den termiska komforten. Huvudsyftet med examensarbetet är att förklara hur det går att uppnå  förbättrat inomhusklimat och samtidigt minska energiförbrukningen. Genom att minska energibehovet kan företag bli mer konkurrenskraftiga och samtidigt rusta sig mot de stigande elpriserna. Det finns även en ekonomisk fördel för företag såväl som för privata bostäder. Examensarbetet består utav en fallstudie, där luftenstemperatur och fuktighet kommer at loggas och data genereras. Loggning kommer att  ske vid två tillfällen. Först i början för att få en uppfattning om varför  personalen upplever dåligt inomhusklimat och sedan efter justering av luftflödena  för att se skillnaden i förändringen av inomhusklimatet och energipåverkan.   Genom att justera systemet och sammanställa resultat har forskningsfrågan ”Kan inomhusklimatet förbättras samtidigt och samtidigt minska energiförbrukningen?”  besvarats. Litteraturstudien visar att om alternativa ventilationsprinciper  används, istället för det konventionella omblandande systemet, går det att minska  energiförbrukningen samtidigt som inomhusklimatet förbättras. Detta har gjorts  genom att golvventilation använts där tilluften tillförts lågt och undertempererad för att luften ska stiga genom de termiska krafterna. Resultatet visar att termisk komfort försämrats enligt enkätstudierna, men samtidigt visar det en förbättring av  inneklimatet i enskilda frågor. Mätresultaten indikerar även på förbättrad  ventilation och inomhusklimat. Slutligen presenterades energibesparingsåtgärder som företaget kan göra för att minska energibehovet och samtidigt förbättra den termiska komforten.

<p>Agglomeration (the sticking together of particles) is often the major growth mechanism in granulation processes. The population balance equation (PBE) is a mathematical framework that is often applied to systems to describe how the particle size distribution changes as a function of time. Different kinetic terms are included in the PBE to describe the different particle growth mechanisms. In this work, a new kinetic model framework is proposed for the growth mechanism binary agglomeration. Binary agglomeration means that only two particles are involved in an agglomeration event. The generality of the new model framework is an advantage over the previous coalescence kernel framework. It is shown that an existing coalescence kernel model can be expressed by means of the new framework.</p><p>The new model framework is then adapted to the special case of fluidized bed granulation (FBG) by proposing/choosing expressions for the three submodels in the model framework. An advantage of the new FBG model is that a maximum number of agglomeration events per unit time can be estimated. This means that the model is one step closer to being used predictively. At the moment, no population balance models can predict granulation processes where agglomeration is the dominant growth mechanism. It is shown that both the new FBG model and an existing model could fit experimental data well, however, the new model reflects the situation that the presence of surface liquid is rate limiting for the agglomeratio process.</p><p>Experiments in a laboratory batch fluidized bed granulator were carried out. Samples of the particle size distribution were taken at intervals during an experiment. These data were used to fit the model parameters of the FBG model. The dissertation includes a discussion of the effect of certain operating conditions such as bed temperature and liquid spray rate on a model parameter.</p>

<p>Fiberweb Sweden AB är en ledande tillverkare av polypropenbaserad fiberduk med Europa som huvudmarknad. När extrudering och spinning av polypropen till trådar utförs genereras beroende på polypropenets relativa känslighet för termisk nedbrytning lättflyktiga organiska föreningar vid smältning. Vid fiberspinning separeras den resulterande gasströmmen från produktflödet och behandlas innan det släpps ut i recipienten. Detta uppnås genom en för gasströmmen installerad kondensor. Det huvudsakliga syftet med examensarbetet är att undersöka möjligheten att minska företagets utsläpp av lättflyktiga organiska föreningar genom att studera den befintliga kondensorns ingående kylvattentemperatur och dess inverkan på kondensatmängd. Arbetet innefattar även framtagandet av förslag gällande kort- och långsiktiga lösningar avseende företagets utsläpp till luft. Av den anledningen har mycket av tyngdpunkten av arbetet lagts på förståelsen av grundproblematiken genom att undersöka mekanismen för hur rökgaserna bildas. Detta innefattar kunskapen i grunderna för de organiska radikalreaktioner som sker vid den termiska nedbrytningen av polypropen vid extrudering. Den praktiska delen av arbetet är uppdelat i fyra försök. Genom att bygga en kondensationsenhet och koppla ett delflöde från rökgasreningsprocessen är försök genomförda med två olika gasflödeshastigheter och kylvattenflöden.</p><p>Utvunnet kondensat vägs som funktion av tid. Effektivitetsgraden beräknas som funktion av inkommande gasmassflöde. Resultaten indikerar att genom temperatursänkning från 21C kondensatmängden fördubblas och med potentialen att minska Fiberwebs utsläpp till luft med mellan 2 % till 15 % (per spinnbeam). Den teoretiska beräkningen som utfördes visar en potentiell minskning av utsläppen till luft mellan 25% till 42%.</p><p>Effekten av uppehållstid undersöktes. Planerade och oplanerade produktionsstopp resulterade i otillräcklig upplösning av resultaten beträffande uppehållstid. Resultat tyder på att processens installerade värmeväxlare (WRT) är underdimensionerad.</p>

<p>This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened.</p><p> </p><p>I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator. The purpose for that was to open the valve if the temperature dropped more than one degree inside. With the help of a program called IDA it was calculated that, if the temperature drop five degrees, they would have sixteen hours at the heating power plant to open the flow before the sensor open the valves.</p><p> </p><p>After careful consideration I came up with the conclusion that the wireless network must be the best solution. Mostly because you can monitor all the clients in the system from the heating power plant and that will make it easier to discover faults and temperature differences.</p><p>Wireless networks is already a well tested solution in form of wireless controlled electricity meters so it shouldn’t be to much of a problem connecting these sensors to it either.</p>