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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.
1

Making grid capacity available through heat pump control

Arding, Karin, In de Betou, Siri January 2019 (has links)
In this report the problem of constructing a bus depot with electrical buses despite the lack of grid capacity, was analyzed. A potential solution is investigated, namely smart control of heat pumps in industries. The possibility of allocating grid capacity to the bus depot by reducing power consumption in heat pumps during peak hours, is taken into consideration. The maximum amount of released capacity in an industrial area is calculated through the controlling of heat pumps. This investigation was made through simulations with a simplified building energy model (lumped capacity model) which was applied to a reference building. After mapping the area Boländerna and the geothermal wells located there, IKEA Uppsala was chosen as the reference building, since a third of the total number of wells were found in that area. To take the whole capacity of Boländerna into account, the model was scaled up to estimate the total, possible reduction of power. The bus depot requires 6 MW nighttime and 4 MW daytime, the total amount of electrical power that could be withdrawn, if all heat pumps were on maximum heat, in the chosen area were 0.75 MW and by controlling the heat pumps during an optimized level, the amount of 142 kW could be made available to the electric grid. 142 kW is not enough cover the need for the bus depot but it could supply the need for a slow charger to one of the buses and is therefore a possible sub-solution to the larger problem.
2

Evaluation of bus depot’s environmental impact and recommendations for improvements by material optimisation and improved energy efficiency

Chen, Guojing, Paulsson, Jill January 2015 (has links)
The public transportation in Stockholm is expanding and in order to meet the new demand the amount of buses and depots will have to increase within the city. As a result, it is getting more important to evaluate and analyse the performance of bus depots in order to reduce its environmental impact. The aim of this work is to study the production and operational phase during a bus depot’s life cycle and introduce saving measures that can reduce the emission of carbon dioxide equivalents (CO2eq). This study is conducted in collaboration with Skanska and the depot chosen for this study is currently under construction and located in Charlottendal, Värmdö. A base model is created for the whole bus depot area and the environmental impact is evaluated regarding the activities and usage of materials during production and the energy usage during operation of the depot. The evaluation of the model is performed by using the calculation tools IDA ICE, Anavitor, SPIK and Excel, and the environmental impact is expressed in terms of emission of CO2eq during the lifetime of the depot, which is assumed to be 50 years.  In order to investigate how bus depots can be built to be more climate neutral and energy efficient, several saving measures are evaluated in four cases. The first two cases are focusing on optimising the usage of materials in the building process, by reducing the material groups with the highest environmental impact and considering green construction solutions. The other two cases are aiming towards enhancing the energy performance of the depot, by reducing the usage of energy according to BBR and deliberating an indoor parking place for the buses. The total emission of CO2eq from the base model is determined to be approximately 16 000 tonnes during the lifetime of the depot. About 42 percent of the environmental impact is instigated during the production phase and the rest of the emission is caused by the use of electricity and heat during operation. By considering the implemented measures it can be concluded that the largest reduction in emission can be obtained by optimising the usage of materials on the site, which is achieved by reducing two of the largest materials groups consisting of concrete and asphalt. By reducing the usage of these materials the total emission from the production phase can be reduced by approximately 9 percent and the total emissions can be reduced by up to 4 percent.  To verify the obtained results a sensitivity analysis is performed where three important parameters are investigated. The chosen parameters are; the assumption of the emission factors for the electricity and district heating mixes and the required heating demand for the buses. According to the sensitivity analysis the final results are highly related to the considered parameters. For instance, if the delivered district heating is assumed to be supplied by Fortum, which is the main distributor within Stockholm, it can be concluded that an indoor parking place for the buses is the most beneficial solution to reduce the total emissions. By building a new base hall the emissions instigated from the total heating demand can be reduced by 55 percent and the total emissions can be reduced by 25 percent. / Kollektivtrafiken i Stockholm genomgår i dagsläget en utbyggnation och för att möta det ökade behovet på transportmedel så måste antalet bussar och bussdepåer att öka i området. På grund av detta blir det mer och mer viktigt att utvärdera och analysera bussdepåernas prestanda för att kunna minska miljöpåverkan från dessa verksamheter. Syftet med detta arbete är att studera produktion- och driftfasen under en bussdepås livscykel samt presentera åtgärder som kan leda till en minskning i utsläppen av koldioxidekvivalenter (CO2ekv). Detta arbete utförs i sammarbete med Skanska och den studerade bussdepån, som ligger i Charlottendal på Värmdö, är för tillfället under konstruktion. För att kunna utvärdera den valda depån skapas en basmodell där klimatpåverkan utvärderas utifrån de aktiviteter och material som används i produktionsfasen och den energi som används under driften av depån. De beräkningsverktyg som har används i utvärderingen av depån består av IDA ICE, Anavitor, SPIK och Excel, och klimatpåverkan från depån uttrycks i ton CO2ekv under dess livslängd, vilken har antagits till 50 år. För att undersöka hur depåer kan konstrueras för att vara mer klimatneutrala och energieffektiva så utvärderas olika besparingsåtgärder i fyra fall. Fokus för de två första fallen ligger på att optimera materialanvändningen i byggprocessen, vilket inkluderar en minskning av de material som genererar i de största utsläppen samt en analys av mer miljövänliga konstruktionslösningar. De andra två fallen riktas istället mot att förbättra energiprestandan av depån genom att minska energianvändningen enligt BBR och överväga en inomhusparkering för bussarna.  De totala utsläppen från basmodellen utgör cirka 16 000 ton, där 42 procent orsakas under produktionsfasen och de resterande utsläppen kommer från driften av depån. Utifrån analysen kan man dra slutsatsen att den största minskningen av utsläpp kan åstadkommas genom att dra ner på mängden betong och asfalt i produktionsfasen. Genom att minska på dessa material kan utsläppen från produktionsfasen minskas med ungefär 9 procent och de totala utsläppen kan minskas med 4 procent. I känslighetsanalysen undersöks tre huvudsakliga parametrar som har en stor inverkan på det slutliga resultatet av beräkningarna. Dessa parametrar består av de valda energimixerna för elektricitet och fjärrvärme samt värmebehovet för bussarna. Enligt resultatet i känslighetsanalysen så är en inomhusparkering den förbättringsåtgärd som leder till den största minskningen av utsläpp. Detta resultat fås då fjärrvärmen antas levereras av Fortum, som är den största leverantören i Stockholmsområdet. Genom att investera i en ny busshall kan det totala värmebehovet för bussdepån minskas med 55 procent och det totala utsläppet med 25 procent.
3

Bussparkering inomhus i Hall kontra utomhus på Bussvärmeramp : Energiutmaning - ett arbete för hållbar förändring / Estimates regarding Energy Consumption concerning Outdoor versus Indoor Bus Parking

Lindberg, Malin January 2016 (has links)
Stockholms läns landsting är en demokratiskt styrd organisation där en av huvuduppgifterna är att länets invånare får tillgång till en väl fungerande kollektivtrafik. Trafikförvaltningen i Stockholm ansvarar för att utveckla och förvalta kollektivtrafiken. Ett mål är att öka resandet med kollektivtrafiken och samtidigt uppnå miljömål. En ren, hel och lagom varm buss ökar kundnöjdheten och främjar dessutom arbetsmiljön för bussföraren. Idag är det vanligaste sättet att parkera våra bussar utomhus längs så kallade bussvärmeramper. Tekniken har genom åren förändrats i bussen men det har inte skett i samverkan med bussvärmerampen. Arbetsmiljön vid förarplatsen kräver enligt ett regeringsbeslut temperaturen 5 °C vid förararstolen och tillufttemperaturen 10 °C vid defrostermunstycket, vilket då är det minsta kravet när bussen ska tas i bruk vid arbetspassets början. Bussar som parkeras utomhus kräver stora mängder energi för att klara de krav som finns för bussförarens arbetsmiljö och om vi istället parkerar bussarna inomhus så kan vi spara pengar och uppnå organisationens miljömål på vägen. Syfte med examensarbetet är att undersöka hur snabbt det går att räkna hem en investering genom att bygga hall istället för bussvärmeramp. Arbetet belyser bussens parkering och arbetsmiljön för bussföraren och de fördelar och nackdelar som finns om vi istället parkerar våra bussar inomhus i hall. För att öka intresset för att förändra behöver vi lära oss mer om förutsättningarna i bussdepåerna och en investering kan hjälpa trafikförvaltningen i Stockholm att minska energianvändningen, öka kundnöjdheten, förbättra arbetsmiljön för bussföraren och skydda våra bussar mot väder och vind. / Stockholm County Council is a democratically controlled organization, one of their main responsibilities is that people has access to a well-functioning public transport. Trafikförvaltningen of Stockholm is responsible for developing and taking care of the public transport. One aim is to increase traveling by public transport while achieving environmental objectives. A bus that is clean, without any dents of fault and temperately warm will increase customer satisfaction and promote working as a bus driver. The most common way to park our buses today is outside lined up along the heating ramps. The technology in the bus has been developed over the years but the heat ramps haven’t been developed as much. The working environment the driver requires, according to a government decision, is temperature 5 °C at the driver's seat and supply air temperature 10 °C at the defroster jets these are the minimum requirements for the bus when it takes into service at the beginning of a shift. Buses parked outdoors require a large amount of energy to meet the requirements of the bus driver's working environment. If we instead park buses indoors we can save money and achieve environmental objectives. The aim of this master thesis is to investigate pay-back time for the investment of parking buses indoors instead of parking buses outdoors on heating ramp. The work highlights the bus parking condition and the working environment for the bus driver the advantages and disadvantages if we park our buses indoors in halls instead of outdoors. We need to learn more about the conditions in the bus depots to increase interest of change. An investment can help the organization achieve environmental goals, reduce energy consumption, improve the working environment for the bus driver, increase customer satisfaction and protect our buses from bad weather and become independent of the outdoor temperature.
4

Smart charging of an electric bus fleet

Färm, Emil January 2021 (has links)
Controlling the balance of production and consumption of electricity will become increasingly challenging as the transport sector gradually converts to electric vehicles along with a growing share of wind power in the Swedish electric power system. This puts greater demand on resources that maintain the balance to ensure stable grid operation. The balancing act is called frequency regulation which historically has been performed almost entirely by hydropower. As the power production becomes more intermittent with renewable energy sources, frequency regulation will need to be performed in higher volumes on the demand side by having a more flexible consumption. In this report, the electrification of 17 buses Svealandstrafiken bus depot in Västerås has been studied. The aim has been to assess different charging strategies to efficiently utilize the available time and power but also to investigate if Svealandstrafiken can participate in frequency regulation. A smart charging model was created that demonstrated how smart charging can be implemented to optimize the charging in four different cases. The simulated cases were: charging with load balancing, reduced charging power, frequency regulation, and electrifying more buses. The results show that the power capacity limit will be exceeded if the buses are being charged directly as they arrive at the depot and without scheduling the charging session. By implementing smart charging, Svealandstrafiken can fully charge the 17 buses within the power capacity limit of the depot with 82 minutes to spare. By utilizing this 82-minute margin in the four different charging strategies, it was found that Svealandstrafiken can save 88 200SEK per year by load balancing, save 30 000 SEK per year by reducing the charging power by 10 %, earn 111 900 SEK per year by frequency regulation or electrify five more buses. Reducing the charging power may also increase the lifetime of the batteries but quantifying this needs further studies. Conclusively, there is economic potential for Svealandstrafiken for implementing smart charging.

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