The cooling system of a DC-motor is examined in this thesis. A change of direction of the cooling air is desired to prevent the generated coal dust from entering into the windings of the machine. Ultimately this will have a negative effect on the cooling in the machine and the loss of cooling needs to be compensated through other ways. The purpose of this thesis is to work for an improved operational safety and performance of the DC-motor and to make it more competitive in the market. By modelling the interior geometry of the machine and defining the boundaries in the software programs Gambit and FLUENT respectively, the motion and the heat transfer of the airflow could be simulated. The simulation results would give us an understanding of the flow pattern which later could be used to develop design modifications on the cooling system of a DC-motor. In this thesis the main focus lies on creating a simulation model with a sufficiently fine mesh size.

The energy use in a workshop company has been examined in this work in order to find areas for energy efficiency improvement. The combined oil and electricity heating in the company were compared with other alternative heating systems including cooling of the premises in following combinations: Ground source heat pump for heating and cooling District heating and absorption cooling District heating and low temperate surface water cooling Energy use, operation costs and carbon dioxide emissions were calculated for the current heating systems and the three alternatives including cooling. The ground source heat pump for heating and cooling decreases bought energy with 34 MWh annually compared to current heating only. The district heating and low temperate surface water cooling has the largest reduction of operation cost and carbon dioxide. The operation cost decreases with 42 kSEK and the carbon dioxide with 43 metric ton CO2 annually. The differences between the alternatives were smaller concerning the operation costs. The ground source heat pump alternative had smaller reductions of carbon dioxide than the other two alternatives with district heating. An alternative heating and cooling system can also lead to alternative energy use. The choice is between electrical or heat energy. A weighting can be done to evaluate the energy use for heating on basis of how much energy is needed in order to generate the energy the end user buys. A 2.5 factor for electrical energy entails the alternative with district heating and low temperate surface water cooling gets the lowest heating and cooling energy in comparison. An inventory of the lighting was also done. The company has already an energy effective lighting but yet another saving of 2 MWh can be done annually without replacement of armatures. Finally, the operation time of the compressor was calculated with a mean value of 11 hours per day. The compressor delivers pressure air to machines and tools. There can be a great demand for pressure air in the workshop but the operation time can also be an indication of leakage in the air net.

Biogas is increasingly used for fuel in for example vehicles and it´s produced in a biogas processconsisting of the steps of pretreatment, digestion and gas cleaning. The pretreatment is a method usedto increase the gas production and / or destroy pathogens. The digestion is the stage when anaerobicmicroorganisms convert bio-mass of a substrate to a raw gas containing about 65% of methane. Thegas cleaning is used to increase the methane content to about 97% so the gas can be used for motors invehicles. The biogas part of the Ekeby sewage plant in Eskilstuna is using multiple substrates. Sewagesludge is mostly used but also other substrates, like food waste. The time for processing is in average25 days before the content is taken out for drying and finally for use as cover material. The producedgas will be cleaned in a water scrubber before pressurization and after that used as fuel for vehicles.The usage of support energy in the biogas process is essentially district heating, electricity and oil. Theoverall efficiency term is the energy produced in the gas minus the supporting energy divided with theenergy from possible biogas production of the substrates. For calculation of a continuous process thefact that there is always a part of the substrates which not will be digested has to be considered.Another thing to think about is that the inserted energy as material will not be converted to gasimmediately, several days is needed. In 2009 the overall efficiency in Ekeby biogas plant was inaverage 70.5%, and the value was higher during the summer than the winter. Calculation of overallefficiency of a biogas plant will always involve some uncertainties because differences of thecomposition of the substrates, the condition of the micro-organisms, digestion of many substrates atthe same time etc.

Samhällets normer och riktlinjer är att dagens byggnader ska minska sinenergianvändning för att erhålla en bättre energiprestanda. För att möjliggöra detta harnya lagar tagits fram för att säkerställa att så är fallet. Högskolan i Halmstad (HH) beståridag av 18 byggnadskroppar, var och en med sin egna unika energianvändning. För att fåen helhetsblick över HHs energisituation har mätvärden för fjärrvärme, kyla samt el tagitsfram. Uppgiften att få fram dessa mätvärden har varit mödosam då flera instanser frånbåde HH, leverantören samt fastighetsförvaltaren har behövt rådfrågas. Dessa mätvärdenhar behandlats utefter riktlinjer från Boverket angående hur energideklarationer skautfärdas. Där har dock funnits mätvärden som ej har kunnat erhållas, detta beroende av attflera byggnader delade på samma anslutningspunkt, detta har gjort att en uppdelning påhur mycket energi varje byggnad använder sig av har varit omöjlig att svara på. Vid dessasituationer har de byggnadernas energianvändning samt ytor slagits samman för att sedanbli behandlade som en byggnad. Ytterliggare förenklingar har förekommit frånleverantören då flera kunder har delat på samma anslutningspunkt där separata mätareinte har existerat. Vid dessa tillfällen har leverantören fördelat energianvändningenprocentuellt mellan kunderna, en fördelning som uppfattas som hämmande förenergieffektiviserings åtgärder. Fördelning av denna typ påvisar inte den verkligaenergianvändningen i en specifik byggnad. Vid jämförelse av de mätvärden sominhämtats från leverantören och de utförda energideklarationerna har flera felaktigheterpåträffats. I energideklarationerna har förväxling av ytor förekommit. Även renaförsummande av kyla har förekommit. Det slutgiltiga resultatet visar på att HHsbyggnader har högre energianvändning än vad de dokument som enligt samhället skasäkerställa den energiprestanda varje byggnad innehar. / Society's standards and guidelines say that today's buildings shall reduce their energyconsumption to obtain a better energy performance. To make this possible new laws havebeen formulated to ensure that this is the case. Halmstad University (HH) consists of 18building cells, each with has its own unique energy usage. To get an overall image overHH’s energy situation, the values for heating, cooling and electricity have been collected.The task of obtaining these values has been difficult were multiple instances in HH, theenergy provider and the property manager has been consulted. These values have beentreated along the guidelines of the National Housing Board on how the energyconsumption documents should be created. There have been some values that areunobtainable, the reason for this is because several buildings shared the same connectionpoint for heating, cooling and energy, because of this a breakdown of how much energyeach building uses have been impossible to answer. In these situations all of the buildingsenergy consumptions and surfaces have been pooled and then been treated as onebuilding. Further simplification has been made. In some instances many differentcustomers have shared the same connection point even though separate meters for eachcustomer have not existed. On these occasions the energy provider has divided the energyconsumption between the energy customers only with the means of a fixed percentage, adistribution that is perceived as a disincentive to energy efficiency measures.Distributions of this type do not show the actual energy usage in a specific building.When comparing the values obtained from the energy provider and the energyconsumption documents, several errors were found. Some of the building surfaces havebeen switched. Even pure neglections have occurred. The final result shows that HH’sbuildings have higher energy consumption than the documents that society refers to tooensure that the energy performance of each building is known.

Conducting polymers (CP) have received great attention in both academic and industrial areas in recent years. They exhibit unique characteristics (electrical conductivity, solution processability, light weight and flexibility) which make them promising candidates for being used in many electronic applications. Recently, there is a renewed interest to consider those materials for thermoelectric generators that is for energy harvesting purposes. Therefore, it is of great importance to have in depth understanding of their thermal and electrical characteristics. In this diploma work, the thermal conductivity of PEDOT:PSS is investigated by applying 3-omega technique which is accounted for a transient method of measuring thermal conductivity and specific heat. To validate the measurement setup, two benchmark substrates with known properties are explored and the results for thermal conductivity are nicely in agreement with their actual values with a reasonable error percentage. All measurements are carried out inside a Cryogenic probe station with vacuum condition. Then a bulk scale of PEDOT:PSS with sufficient thickness is made and investigated. Although, it is a great challenge to make a thick layer of this polymer since it needs to be both solid state and has as smooth surface as possible for further gold deposition. The results display a thermal conductivity range between 0.20 and 0.25 (W.m-1.K-1) at room temperature which is a nice approximation of what has been reported so far. The discrepancy is mainly due to some uncertainty about the exact value of temperature coefficient of resistance (TCR) of the heater and also heat losses especially in case of heaters with larger surface area. Moreover, thermal conductivity of PEDOT:PSS is studied over a wide temperature band ranging from 223 - 373 K.

The sun is a huge energy source with great potential of providing energy to the heating of homes and other buildings in an environmentally sustainable manner. In order to provide buildings with energy from the sun it is necessary to transfer the energy supply over time to when the demand arises. By storing the heat in a seasonal storage, solar energy from the summer can be used in the winter when the demand for heating is greatest. Today's existing plants are mainly in Europe and particularly in Germany. These facilities are designed to supply heat demands greater than 400 MWh and covers about 40-50 % of this need which consists of energy for space heating and domestic hot water. How much of the heat demand that is covered, the solar fraction, is partly due to losses from the storage which in turn is connected to the surface area of the storage. The bigger a storage, the smaller the losses because of the decreasing relationship between surface area and storage volume. Looking at the size of the seasonal storages that are currently in operation, the question if seasonal storage is also suitable for installations designed for heat demands smaller than 400 MWh arises. Jonas Haglund at the architect office Skanark AB in Karlstad is planning an accommodation of 40 flats and hopes that seasonal stored solar energy can serve as the main energy source for space heating and hot water. In order to make housing more attractive he is considering the idea of adding other features, like a pool and an atrium, that also require heating but with lower temperature requirements. Haglund would like to investigate whether the efficiency of the solar collector increases when the extra energy demands are added and if the energy cost, for those demands, in this way can be reduced. The purpose of this study is to investigate the possibility of covering a large fraction of a small-scale annual heat demand corresponding to about 40 newly built apartments. The study shall present the solar fractions that can be achieved with different storage concepts when storage size and collector area is varied. The study will also answer how the solar fraction will change if a heating demand with lower temperature requirements and varied character is added to the basic domestic heating and if the added energy demand to some extent can be free. These questions are answered by calculations and simulations with the simulation software COMSOL Multiphysics. The results show that it is possible to obtain solar fractions above 80% with sufficient collector area. Suitable storage volume varies depending on the specific storage concept. Simulations of seasonal storage in a tank show that a storage volume of 13 m3/MWh is an appropriate size, while the corresponding figure for duct storage in clay is 20 m3/MWh. An added heating demand of low temperature character increases the efficiency of the solar panels and creates, so called, free energy. / Examensarbete

Syftet med detta examensarbete är att undersöka om det går att minska frånluftsventilationen till tvättapparater för pappersmassaindustrin. Genom att mäta flödet för frånluftsventilationen och mätinstrument vid ångläckaget har undersökningar gjorts om det går att minska frånluftsventilationen.  Examensarbetet har utförds för företaget Metso i Sundsvall som bl.a. tillverkar hela systemlösningar till pappersmassaindustrin. Mätningarna har gjorts på SCA Östrand i Timrå som är en pappersmassa tillverkare.  Inledningsvis ges en presentation över hur pappersmassatillverkning går till och sedan ges en mera genomgående beskrivning av hur Twinroll tvättapparat, spädskruv och standpipe fungerar. I teori delen tas det upp vilka saker som påverkar ångläckaget för tvättapparaten. Det som påverkar är sambanden i ideala gaslagen, fukt och avdunstning. För att beräkna hastigheten med pitotrör har Bernoullis ekvation härleds i teoridelen.   Mätningarna gick ut på först att fastställa frånluftsventilationsflödet från tvättapparaten. Dessa mätningar gav problem i början eftersom frånluften hade hög temperatur och ånghalt men sedan kunde flödet mätas. För mätningarna användes pitotrör och vinghjulsmätare.  För att fastställa vilket det minsta frånluftsventilationsflöde är innan det bildas ångläckage från tvättapparaten användes för det mänskliga ögat. Det visade att det inte gick att visa hur ångläckage ändrades genom tiden. Mätningar av temperatur- och RH-givare gav dåliga värden förutom när en tillfällig produktionsstörning inträffade. Då fastställs att när produktionen, temperaturen på pappersmassan- och spritsen går ner minskas ångläckaget. RH-givaren visade felvärden pga att inte synbart ångläckage inträffar och att spritsen går i intervaller.  Konceptgeneringen visade att minskade av kåpansluftvolym och ångläckagearean troligtvis är dem bästa lösningarna. Dem andra lösningarna kan testas om energipriserna går upp och då lär dem bli lönsamma.

Huvudsyftet med arbetet har varit att undersöka potentialen för värmedriven kylproduktion, dvs. absorptionskyla, i Linköpings energisystem. Bakgrunden är att många energibolag söker efter nya avsättningsområden för fjärrvärme pga. det överskott på värme som finns sommartid i energisystem med kraftvärme. Dessutom förväntas elpriserna fortsätta stiga då Sverige med stor sannolikhet kommer att följa resten av Europa och gå från ett energidimensionerat system till ett effektdimensionerat system. Till följd av detta blir energieffektiviserande åtgärder allt viktigare och absorptionskyla innebär att mer el kan produceras i ett system med kraftvärme, istället för att konsumeras. Det finns två typer av absorptionskylmaskiner (ABS) tillgängliga på marknaden, antingen har de fjärrvärme eller ånga som drivmedel. Den typ av ABS som drivs av fjärrvärme lämpar sig för produktion av komfortkyla, dvs. kyla som inte behöver komma ned till så låga temperaturer. Ångdriven ABS kan däremot komma ned till lägre temperaturer, något som kan passa vid processkyla. En förutsättning för absorptionskyla är tillgång till billig värme/ånga. Tekniska Verken har tack vare avfallsförbränning tillgång till billig värme. Ångan i systemet produceras däremot idag med olja och el, något som gör det dyrare att generera absorptionskyla med hjälp av ånga. En fallstudie utfördes på de två industrierna Linköpingsmejeriet och Swedish Meats där anslutningsmöjligheterna för absorptionskyla undersöktes. Främst behovet av processkyla har undersökts då det var betydligt större än behovet av komfortkyla. Ett antal fall med olika förutsättningar för att tillgodose dessa kylbehov till de båda industrierna har simulerats i MODEST. Utifrån de resultat som erhållits har följande slutsatser dragits. • I dagsläget finns inte tillräckligt med ångproduktion i systemet för att tillgodose både det befintliga ångbehovet samt den mängd ånga som behövs för att framställa kylan. • En investering i nya biopannor till ett kraftvärmeverk kan ge tillräcklig mängd billig ånga och värme för att ge lönsamhet i värmedriven kylproduktion. • Koldioxidutsläppen, lokala såväl som globala, minskar som en följd av övergång från el-kompressorer till absorptionskylmaskiner. En investering i nya biopannor skulle minska utsläppen ytterligare, då fossilt bränsle ersätts. • En investering i en litiumbromid absorptionskylmaskin är inte lönsam vid en så pass liten efterfråga som har varit aktuellt i de undersökta fallen. / The main purpose of this thesis has been to look in to the potential of a production of district cooling using heat as the source of power, i.e. absorptions cooling, in the energy system of Linköping. In the light of the fact that many energy companies are looking for new markets for district heating due to the surplus of heat in the summertime in an energy system with CHP (Combined Heat and Power). Furthermore, the price on electricity is expected to continue to rise since Sweden is most likely to follow Europe’s lead and embrace a power dimensioned energy system. As a result of that transition, energy efficient measures will be more important and absorption cooling implies that more electricity can be produced, instead of consumed, in a CHP system. There are two different types of absorption cooling machines available in the market, with either district heating or steam as the source of power. A machine using district heating as the source of power is most suitable to produce comfort cooling i.e. the cold does not need to attain such low temperatures. A steam driven absorption cooling machine is able to attain the very low temperatures needed for cooling used in the processing industry. A condition for absorption cooling is the access to low-cost heat/steam. Tekniska Verken (an energy company) has due to waste incineration access to low-cost heat. The steam in the energy system is produced with oil and electricity, which makes it more expensive to generate absorption cooling with steam as the power source. A casestudy was preformed at two industries in Linköping, Linköpingsmejeriet and Swedish Meats, where the possibility for connection of district cooling was examined. Mainly the cooling needed in the processing industry has been examined as this is need is considerably larger than the need for comfort cooling. A number of cases with different conditions for producing district cooling have been simulated in MODEST. The following conclusions have been drawn based on the results of the simulations. • In the energy system of today there is not enough steam production to fulfil both the current need for steam and the amount of steam needed for cooling production. • An investment in new CHP-plants using biomass fuels will generate enough heat and steam to be profitable for cooling production using heat as a source of power. • The emission of carbon dioxide will decrease as a result of the transmission from compression cooling to absorption cooling. The emission will decrease further if an investment in new CHP plants with biomass fuels is carried out. This will then replace the use of fossil fuels. • An investment in lithium bromide absorptions cooler will not be profitable with such a small demand as the one in question.

Arvika Fjärrvärme AB, a district heating company from Arvika, today cover 74 % of their total energy production with biofuel wich runs a 16 MW bioler giving process water at saturated liquid state. In recent years Vaporel AB has introduced a new tecnique that gives an external generation of steam after boilers. The concept is built on an adiabatic pressure drop of the saturated liquid in a so called Flashbox which makes a small part of the liquid to evaporate. The generated steam is lead into a turbine where electricity is in a conventional manner. The purpose with this rapport was to do a basic study for the specific system at Arvika where it’s possible to see the potential production of electricity that follows an installation of a flasbox. The final goal was to introduce an economic analysis of a flashox installation at given conditions. To reach our goals we have created a model in Excel where we used the given conditions at Arvika Fjärrvärme to do our calculations. The model has been tested at three different states, of process water returning to potboiler, to be able to decide the optimal operation for the system at present. The studies have resulted in a pressure of the processwater at 14,5 bar (at) and a pressuredrop to 9,5 bar (at) in the flashbox. The condenser pressure is set to 0,5 bar (at) what is equal to 81 ˚C. Energy to the district heating net is produced in the condenser and heat exchanger. The result of our calculations clearly shows that to reach the highest turbine-efficiency as possible and gain the largest profit the highest process-waterflow possible should be used. That means 70 kg/s after present conditions. At the highest boiler efficiency the turbine will produce 694 kW. At this state the water that returns to the boiler will be at temperature 148 ˚C (14, 5 bar). Totally during a year the production of electric energy could reach 2, 47 GWh/year. The energy used by the pumps will increase with 0,21 GWh over the year at that state. Included all economic factors this will generate a profit of 0, 97 million (SEK)/year. To make an installation of a flashbox system more profitable an increased generation of electricity have to be made. This could be done by an installation of new pumps to be able to run the process-water at a larger flow to increase the amount of steam made in the flashbox. / Arvika fjärrvärme producerar idag 74% av sitt värmeunderlag via en hetvattenpanna som drivs med biobränsle och har en maxeffekt på 16 MW. På senare år har företaget Vaporel AB introducerat en ny teknik på marknaden som ger en extern ångproduktion efter hetvattenpannor. Konceptet är byggt på en trycksänkning som medför att delar av det mättade vattnet förångas efter att ha letts in i en så kallad flashbox. Efter flashboxen äntrar ångan en turbin där el produceras på konventionellt vis. Syftet med denna rapport har varit att ta fram en grundläggande studie för Arvikas specifika system där det är möjligt att se den potentiella elproduktionen vid en flashboxinstallation. Det slutgiltiga målet med rapporten har varit att kunna presentera en lönsamhetsbedömning för en flashboxinstallation vid givna driftfall. För att kunna uppfylla uppsatta mål har en Excelmodell konstruerats där beräkningar utförts efter givna förutsättningar, detta utefter tre olika driftfall för att kunna fastställa den mest optimala driften för systemet i dagsläget. Studierna har lett fram till att vi har kunnat fastställa ett maximalt tryck efter pannan på 14,5 bar (at) samt en trycksänkning över flashboxen till 9,5 bar. Kondensortryck efter turbinen har satts till 0,5 bar(a) vilket ger en kondensations temperatur motsvarande 81 ˚C. Energi till att värma fjärrvärmevattnet tas via kondensorn samt en värmeväxlare. Resultatet av våra beräkningar visar tydligt att vi för att nå en så hög turbineffekt som möjligt och därmed en större lönsamhet skall ha ett så högt processvattenflöde som tillåts, enligt dagens förutsättningar 70 l/s. Vid högsta panneffekten kommer turbinen att ge 694 kW, enligt Excelmodellen, vid en returtemperatur till pannan satt till 148 ˚C. Sammanlagt under året, med Arvikas varaktighetsdiagram som grund, kommer vi att kunna producera 2,47 GWh el/år varav pumparna kommer att kräva 0,21 GWh el extra per år. Med alla ekonomiska faktorer inräknade så kommer detta att ge en vinstkalkyl på 0,97 miljoner /år. För att kunna göra dessa installationer lönsamma krävs att vi ökar elproduktionen och därmed den årliga vinsten, detta skulle kunna göras i och med installation av nya pumpar för att uppnå ett större flöde i pannkretsen. Vidare bör en studie göras för att bedöma lönsamheten gällande en ombyggnad av rökgaskondenseringen för att kunna klara en större effekt och därmed kunna använda högre returtemperaturer till biopannan. Detta skulle generera ett högre genomsnittligt flöde över året.

The demand for more accurate measurements is increasing in today’s industry. One reason for this is to optimize production and thus maximize profits. Another reason is that in some cases government regulations dictate that supervision of certain parameters must be followed. At Preemraff Lysekil there are basically four reasons for measuring skin temperatures inside fired process heaters, namely; because of government regulations, in order to estimate the load of the fired process heater, to estimate the lifetime of the tubes inside the fired process heater and finally, to determine the need of decoking. However, only the first three of these reasons are applied to H2301/2/3. The current skin thermocouple design has been in use for many years and now the question of how well it measures surface temperature has risen. Furthermore a new weld-free design is under consideration to replace the old skin thermocouple design. Another question is therefore how well the new design can measure the surface temperature under the same operating conditions as the old one. In order to evaluate this, three–dimensional computer simulations were made of the different designs. As this thesis will show, the differences in calculated skin thermocouple temperature and calculated surface temperature is about the same for the two designs. However, the current design will show a lower temperature than the surface temperature, while the new design will show a higher temperature. Regarding the core of the skin thermocouple designs, namely the thermocouple, no hard conclusions can be drawn, although the industry appears to favor type ’N’ over type ’K’.