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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.
101

Val av uppvärmningssystem utifrån ett kostnads- och miljöperspektiv

Acuna, Gerardo, Rooth, Patrik January 2012 (has links)
Uppvärmningskostnader för äldre flerbostadshus utgör oftast en tung post i de löpandedriftskostnaderna. Att som fastighetsägare se över vilka alternativ till uppvärmning det finnspå marknaden kan leda till stora besparingar i en värld där energikostnader bara ökar ochökar. Lamellhus från perioden 1941-1960 utgör en stor andel av Sveriges bostadsbestånd ochär i behov av modernisering. I denna rapport studerar vi uppvärmningskällorna fjärrvärme ochgrundvattenvärmepump för en sådan byggnad ur ett kostnads- och miljöperspektiv.Genom att skapa en modell av byggnaden i VIP Energy beräknas behovet av tillförd energiför uppvärmning och tappvatten. Livscykelkostnader för de olika uppvärmningsalternativenberäknas under en 20-års period. Utsläpp som de olika systemen står för beräknas sedan förett år. Resultaten från LCC- och utsläppsberäkningen analyseras i diskussionen. De olikasystemen bedöms utifrån tre synvinklar: kostnader, miljöpåverkan och samhällperspektiv.En grundvattenvärmepump är klart att föredra ur det ekonomiska perspektivet. I miljö- ochsamhällsperspektivet är det dock svårare att definiera det bästa alternativet. Sett utifrån denenskilda byggnadens miljöpåverkan minskar grundvattenvärmepumpen utsläppen, dockskapar den ett ökat behov av primärenergi medan fjärrvärme utnyttjar befintliga lågvärdigarestprodukter som bränsle och producerar värme och el, vilket är positivt för både samhälleoch miljö. / Heating costs for older multi-dwelling buildings are usually a heavy item of operatingexpenditure. As a property owner, reviewing the options for heating available on the marketcan lead to big savings. In this report we study the heating sources district heating andgroundwater heat pump for a multi-dwelling building from a cost and environmentalperspective.A groundwater heat pump is clearly preferable from an economic perspective. However, it isdifficult to define the best option from an environmental and a society perspective. Thegroundwater heat pump reduces the individual building's emissions although it increases theneed for new produced energy on a society perspective.
102

Effektutjämning av Fjärrvärmelast genom att utnyttja Byggnaders Värmetröghet : En simuleringsstudie / Heat Load Balancing of District Heat Load by Using Thermal Inertia of Buildings : A simulation study

Hagman, Ida January 2024 (has links)
This thesis explores the potential of using building thermal inertia for thermal load balancing. It focuses on calculating time constants and determining the duration and amount of load that can be decreased in the building without the indoor temperature being decreased more than 0.5 degrees. Using data on residential area, construction year, building material, and supplied heat load, the study addresses the following main questions: calculating time constants for selected buildings, the quantities of supplied heat load that can be decreased, and over what duration of time, for the studied buildings.The method consisted of mapping a large amount of buildings from construction year, building material and relative heat demand to make a selection of buildings that were common and can be representative for more buildings. For each selected building the time constants and duration times were calculated. A model for heat load demand for space heating was made for each selected building to calculate the effect available for heat load balancing.Buildings with larger residential areas, higher heat demands per building, and lower heat demand per square meter exhibit significant potential for heat load balancing. The study identifies a newly constructed building with concrete structure and facade as having the highest thermal inertia. There is also potential for heat load balancing in larger, energy-efficient brick-built buildings.
103

Termisk energilagring för Halmstads fjärrvärmesystem

Larsson, Edvin January 2024 (has links)
A significant portion of Sweden's current energy production is dedicated to heating homes and buildings. Simultaneously, we anticipate a substantial increase in electricity usage in the future. This places a greater demand on district heating companies, among others, to meet the rising demand intelligently. Previously, more production facilities have been built to address the growing demand for heat. In the forthcoming development, district heating is considered to play an increasingly crucial role in the evolution of the Swedish energy system. This occurs as society becomes increasingly electrified and electricity systems become more reliant on other energy systems through sector coupling, such as district heating. Integrating thermal energy storage into district heating systems can significantly enhance the energy system's flexibility. This report investigates the potential of integrating thermal energy storage into Halmstad's district heating system and the associated benefits. It examines both short-term and seasonal heat storage. The short-term storage aims to address the daily variations in district heating load, preventing the frequent activation of peak load facilities. Additionally, a seasonal storage system is considered to handle the most significant district heating load fluctuations. Integrating seasonal heat storage into the district heating system would enable power plants to operate at a constant load throughout the year. Suitable storage methods were identified, and economic calculations were performed. The results indicate that installing a 42 000   short-term storage or a larger 830 000   seasonal storage system would be most cost-effective. Halmstad possesses favorable conditions for integrating these heat storage systems. The short-term storage system is designed to handle the annual daily variations in Halmstad's district heating load. The seasonal heat storage system has the capacity to store all the excess cooling energy during the summer period for use during the winter when heating demand is highest. Furthermore, the seasonal heat storage system can replace 54% of the peak load facilities' energy throughout the year. The economic evaluations revealed an annual profit of SEK 12 million for the short-term storage system and SEK 25 million for the seasonal storage system. The payback periods were 3.2 years and 7.6 years for the short-term and seasonal storage systems. / Mycket av den producerande energin i Sverige idag går till att uppvärmning av bostäder och lokaler. Samtidigt som vi har en förväntad kraftigt ökad elanvändning i framtiden. Detta gör att det ställs högre krav på bland annat fjärrvärmebolagen för att möta den ökande efterfrågan på ett smart sätt. Tidigare så har det byggts ut fler produktionsanläggningar för att möta den ökande efterfrågan på värme. I den kommande utvecklingen så anses fjärrvärmen att spela en allt viktigare roll i utvecklingen av det svenska energisystemet. Detta sker när samhället elektrifieras i allt högre grad och elsystem blir mer beroende av andra energisystem genom sektorkoppling såsom fjärrvärmen. För att främja flexibiliteten i energisystemet så kan integrering av termiska energilagring inom fjärrvärmen ha en stor betydelse. Rapporten undersöker möjligheter med att integrera termisk energilagring för Halmstads fjärrvärmesystem och vilka nyttor det medför. Det undersöks både korttidslagring av värme och säsongsvärmelager, där korttidlagret ska klara de dygnsvariationerna i fjärrvärmelasten för att förhindra starter av spetsanläggningar, men även ett kottidslager som klarar de största variationerna i fjärrvärmelasten. Att integrera ett säsongsvärmelager i fjärrvärmesystemet ska göra att värmeverken kan drivas på konstant belastning under hela året. Lämpliga lagringsmetoder togs fram samt ekonomiska beräkningar och resultatet visar att det mest lönsamma är att installera ett korttidslager på 42 000   eller ett större säsongslager på 830 000  . Halmstads förutsättningar för att integrera dessa värmelager är goda. Korttidslagret har dimensionerats för att klara de dygnsvariationerna i fjärrvärmelasten i Halmstad över året. Säsongsvärmelagret har möjlighet att lagra all bortkyld effekt som kyls bort under sommarperioden, för att sedan använda energin under vintern när värmebehovet är som störst. Men även 54% av spetsanläggningarnas energi kan ersättas med säsongsvärmelagret över året.         De ekonomiska resultaten resulterade i en årlig vint på 12 miljoner SEK för korttidslagret respektive 25 miljoner SEK för säsongslagret. Payoff-tiden var på 3,2 år för korttidslagret och 7,6 år för säsongslagret.
104

Effektbegränsning värme : Analys och energieffektivisering av värmesystem på Umeå campus / Power limitation of heat : Analysis and energy efficiency improvements of the heating systems at Umeå campus

Eriksson, Mattias January 2024 (has links)
För majoriteten av Umeå universitetscampus finns en anslutningspunkt för fjärrvärme från Umeå Energi. Under januari 2024 uppstod problem när fjärrvärmeeffekten överskred den abonnerade nivån under några extremt kalla dagar, vilket resulterade i straffavgifter från leverantören. Projektets syfte är att analysera och lösa överbelastningsproblemen genom att hitta och jämföra olika förbättringar för värmesystemen på campus. Effektsignaturer analyserades för utvärdering av variationen i den inköpta fjärrvärmen på Umeå universitetscampus, för drift under och utanför verksamhetstid. Resultaten visar en maximal potentiell effektreduktion på 29,4% vid DVUT (dimensionerande vinterutetemperatur). En strategisk driftstrategi kan tillämpas genom att ändra styrsystemets globala tidsschema till röd dag för att uppnå effektreduktion i byggnader utan närvaro. Detta motsvarar en maximal potentiell ekonomisk besparing på 1,7 miljoner kronor för den totala effektreduktionen. Effektkartläggning av Fysikhusets värmesystem utfördes. Resultatet vid DVUT visade att radiatorerna endast stod för 30% av fjärrvärmeeffekten, LA001 (ventilationsaggregat i Fysikhuset, laborationssalar) 64% och LA002 (ventilationsaggregat i Fysikhuset, kontor) 6%. Fysikhusets variation i fjärrvärmebehov under och utanför verksamhetstid vid DVUT visar en minimal skillnad på endast 0,3%, vilket främst beror på värmesystemens utformning och verksamheten som bedrivs. Radiatorernas effektbehov i Fysikhuset vid DVUT analyserades vid sänkning av inomhustemperatur från 21°C till 18°C. Resultaten visar en effektreduktion på 8,7kW och en ekonomisk besparing på 5 746kr, jämfört med radiatorernas normala effektbehov på 43,5kW. Sänkning av ventilationsflöde i Fysikhuset enligt BBR (Boverkets byggregler) visar potential för betydande effektreduktion, med möjlighet att minska ventilationen upp till 61,8% under närvaro och 89,1% utanför närvaro, vilket kan leda till en ekonomisk besparing på mellan 4 700 - 59 500kr. Beräkningar visar att för varje grad (°C) sänkning av tilluftstemperaturen i Fysikhusets ventilation kan en effektreduktion på LA001 och LA002 uppnå 4kW och 3,7kW per grad respektive, vid DVUT. / For most of the buildings on Umeå University campus there is one main connection point for district heating from Umeå Energi. In January 2024 problems occurred when the district heating output exceeded the subscribed level during some extremely cold days, resulting in penalty charges from the supplier. The purpose of the project is to analyse and solve the overload problems by finding and comparing different improvements for the heating systems on campus. Power signatures were analysed for evaluation of the variation in the purchased district heating at Umeå University campus, for operation during and outside business hours. The results show a maximum potential power reduction of 29,4% at DVUT (dimensioned winter outdoor temperature). An operating strategy can be applied by changing the control system's global time schedule to public holiday to achieve a power reduction in unoccupied buildings. This corresponds to a maximum potential financial saving of SEK 1,7 million for the total effect reduction. Power mapping of the building “Fysikhusets” heating system was carried out. The results at DVUT showed that the radiators accounted for only 30% of the district heating power, LA001 (ventilation unit in Fysikhuset, laboratory rooms) 64% and LA002 (ventilation unit in Fysikhuset, offices) 6%. The district heating demand variation in Fysikhuset during and outside of operating hours at DVUT shows a minimal difference of only 0,3%, which is mainly due to the design of the heating systems and the operations that are carried out in the building. A power reduction on the radiators in Fysikhuset was analysed by lowering the indoor temperatures from 21°C to 18°C, the results showed a power reduction of 8,7 kW and a financial saving of SEK 5 746. Compared to the radiators normal power requirement of 43,5kW. Reduction of ventilation flow in Fysikhuset according to BBR (Boverket´s building regulations) shows potential for significant power reduction, with the possibility of reducing ventilation up to 61,8% during attendance and 89,1% without attendance, which can lead to a financial saving of between SEK 4,700 - 59,500. Calculations show that for each degree (°C) lowering of the supply air temperature in Fysikhusets ventilation, a power reduction on LA001 and LA002 can reach 4kW and 3,7kW for each degree respectively, at DVUT.
105

Minskat fjärrvärmebehov hos Latitud 64 : Integration av värmepumpar i köldbärarkrets

David, Lindström January 2024 (has links)
Energifrågan är en central fråga i dagens samhälle och för att uppnå en hållbar utveckling krävs det att vi använder energin mer effektivt. Genom att implementera energieffektiva processer och tekniker inom olika sektorer kan vi säkerställa och främja en hållbar utveckling Denna rapport undersöker möjligheten att implementera värmepumpar för att effektivisera energianvändningen hos företaget Latitud 64 i Skellefteå. Syftet med studien är att utreda om värmepumpar kan ersätta delar av deras fjärrvärmeförbrukning och därigenom minska företagets totala energikostnader. Rapporten går igenom teori kring kylteknik, termodynamiska processer och begrepp som COP för att vidare applicera detta på Latitud 64:s specifika förutsättningar. Genom beräkningar och antaganden kring exempelvis kylbehov, värmebehov och energipriser presenteras en analys av energi- och ekonomieffekterna av att installera en alternativt två värmepumpar. Resultatet kommer visa att två värmepumpar på 40 kW med ett COP på 4,3 kan komma att täcka en stor del av Latitud 64:s värmebehov och därmed minska deras fjärrvärmeförbrukning med cirka 60%. Detta skulle innebära att företaget gör en besparing på uppskattningsvis 230 000 kr per år, med en beräknad payback tid ca 2 år. / The energy issue is a central question and to achieve sustainable development it is necessary that we use energy more efficiently. By implementing energy-efficient processes and technologies in various sectors, we can promote a sustainable development. This report deals with the possibility of implementing heat pumps to make use of the energy more efficient at the company Latitud 64 in Skellefteå. The purpose of this study is to investigate whether heat pumps can replace parts of their district heating consumption and thereby reducing the company's total energy costs. The report reviews theory including cooling technology, thermodynamic processes, and concepts such as COP to further apply this to Latitud 64's specific conditions. Through calculations and assumptions about cooling needs, heating needs and energy prices an analysis of the energy and economic effects of installing one or two heat pumps is presented. The result will show that two heat pumps of 40 kW with a COP of 4.3 can cover a large part of Latitud 64's heating needs and reduce their district heating consumption by around 60%. This would mean a saving of approximately 230,000 SEK per year, with an estimated payback period of approximately 2 years.
106

Lågtempererad fjärrvärme i bostadsområdet Tullkammarkajen

Palmer, Simon, Sjöberg Åkerlundh, Theodor, Lomander, Mikael January 2018 (has links)
District heating plays a major part of the energy system used for heat supply in Sweden. The starting point of this parameter study have been to investigate the possibilities to provide the area Tullkammarkajen with efficient district heating supply in help of low temperature residual heat and waste heat from a nearby industry. The area is located in the city center of Halmstad and is currently in its planning phase. Facilities and apartments are planned to be built.The study is based on three different parameters: type of system, system temperatures and energy demand. The different type of systems that is analyzed is conventional districtheating, low-temperature district heating with a heat pump as a complement as well as low-temperature district heating with the primary network’s feed line as a complement. Further comparison was made between these parameters, both from an energy wise perspective as well as from an economic perspective.The underlying idea to this study has been to obtain an energy efficient solution that at the same time suits the principle of sustainable development. However, it can clearly be seen in the presented results that it is more profitable to use more conventional methods that are not adapted to sustainable development, based on today’s market. Thus, the question becomes whether the future of innovative solutions or economical funds should be prioritized.
107

Potential for low temperature district heating system : Integrating 4th generation district heating system with existing technology

Kamal, Majd January 2017 (has links)
This project presents a feasibility study and an investigation of the potential for low temperature district heating system in Västerås. The investigation treats integrations possibilities for 4GDH (4th Generation District Heating) in Kungsängens area in Västerås, which is undergoing a large-scale building-up and construction.  The study is conducted for the company Mälarenergi AB. The advantages of 4GDH technology are identified and analyzed, where energy effectiveness and economic benefits aspects were concluded. Problems with existing technology and higher cooling demand expectations drive 4GDH to be an interesting and necessary technology in the future. Four Different integration solutions between old and new networks are presented, analyzed and discussed. Quantitative analysis conducted where initial cost for the four technical solutions were estimated and compared. The results show that low temperature district heating could lead to reduction in the initial cost for the network by using PEX instead of steel as pipe material. The results show also that one solution using heat exchanger as exchange stations has the lowest cost between the four solutions. The results show that the cost for the retention flow that is linked with 4GDH stands for 20%-30% of the total cost. The importance of the retention flow pipe is investigated using two physical models in OpenModelica and Excel, where simulations were conducted. It is concluded that it is possible to provide Kungsängen area with low temperature district heating without having the retention flow pipe. Three parameters were identified to be critical which are, geographical placement of the consumers, pattern variation for the heat demand and heat systems installed inside consumer’s buildings. The results show also that it might be critical to have a variate and optimized supply temperature for the area, depending on the demand. The simulations of a fictive area that could present a future heat demand for Kungsängen area shows that a temperature of 55°C is satisfying during winter season where the demand is high and a temperature between 60-65°C must be available during spring/autumn seasons and specially during summer. The variation depends directly on the temperature drop through the supply pipes to the consumers. The temperature drop is directly linked with water velocity inside the pipes. The losses increase during summer nights when the heat demand is low which lead to low water velocities.
108

The Effects of Lowered Delivery Temperatures in District Heating : A Quantitative Study / Effekterna of sänkta framledningstemperaturer i fjärrvärmenätet

Julin, Anton, Berthold, Jakob January 2015 (has links)
With development within district heating leading to more incorporation of decentralized production, lowered temperature levels are required to enable these possibilities. Therefore, this study was conducted in collaboration with Fortum with the purpose of investigating and quantifying the effects of lowered delivery temperatures on mass flow and return temperatures. When these effects had been determined, the limiting factors were identified as well as the adjustments needed to enable the lowering delivery temperatures. This study is divided into two sections: a modeling of four type buildings and two case studies of specific areas of the Stockholm district-heating grid. The two sections of the study both use an Excel constructed model to examine the effects of the new proposed delivery temperature levels. The first section uses four type buildings with varying internal temperature levels to display how different secondary systems react to the changes in delivery temperature. The second section contains two case studies of outer parts of the grid where actual buildings are modeled. In the case studies the pipes speeds and secondary systems are analyzed to determine limiting factors for the lowering of the delivery temperatures. Overall this study contributes with quantified results of the effects of four lowered delivery temperature profiles on different customer systems. Analysis of the delivery temperatures showed that the largest change was shifting from the actual delivery temperatures of 2011 to the delivery profile that Fortum currently promised to deliver. The pipes of the studied areas were found not to be a limiting factor even in cases where the when mass flows increased three fold. The greatest limiting factor was determined to be the internal temperatures of the buildings, which set a strict limit and cannot be altered by Fortum without the customers’ cooperation. In conclusion a range of limiting factors were identified that proved to be potential limitations depending on the circumstances of a specific case. Depending on the investment needs in a specific case the economic viability was deemed to most likely be positive. When implementing lowered delivery temperatures in reality it is vital to acquiring data on secondary systems in order to identify the specific limitations of the proposed area. In addition an area of more research on the effects of lowered temperatures on the entirety of the grid as this study only investigates isolated sections.
109

Etablering av lågtempererad fjärrvärme : Utveckling och tillämpning av ett indikatorsystem / Establishment of low-temperature district heating : Development and application of an indicator system

Vanky, Katarina January 2022 (has links)
This master thesis aims to develop an assessment tool for decision-making regarding future establishment of low-temperature district heating (LTDH). The tool is created as an indicator system on behalf of Södertörns Fjärrvärme AB (SFAB). SFAB is currently responsible for the distribution of high-temperature district heating (HTDH) to customers in the municipalities of Huddinge, Botkyrka, and Salem. The indicator system is designed to, in a first assessment step, examine the conditions that a delimited area has for conversion to lower system temperatures to be possible. Each indicator is quantified and graded. When using the system, a weighted final judgement is generated which indicates whether an area is suitable for LTDH or not. Furthermore, the purpose of this thesis is to also evaluate the tool by applying it to various areas within SFAB. This enables analysis and discussion regarding the tool's function in a real context. The development of the indicator system is the main result of the study. It consists of four indicators that take the following aspects into account: qualitative conditions (KA), conditions on the customer side (AA), the economic benefit (CRG), and the system condition (STA). The results from the implementation show that one out of five case-areas have good potential to be converted to LTDH, while the remaining cases fall below the limit for what is considered acceptable. No area from this project ends up over 75% of the maximum score, which would indicate very good potential. To validate the indicators, Pearson's correlation coefficient was calculated. The results show that there is a negligible to a weak correlation between all indicators, except KA & STA which has a strong correlation. For an HTDH area to be relevant for conversion to LTDH, the qualitative context of the area should be suitable, and the secondary side should be able to be supplied with lower temperatures. Furthermore, there should be an opportunity for increased system capacity and finally, a conversion should be economically beneficial. The application of the indicator system is an efficient and uncomplicated approach that makes it possible to identify areas that have the potential to develop district heating in a more sustainable direction. It is also possible for stakeholders to subsequently modify the indicator system if desired. In the longer term, the indicator system is an incentive for new business opportunities, increased energy efficiency, and increased economic benefits.
110

Fjärrvärmedriven absorptionskyla i Hedemora och Säter / District Heating Driven Absorption Cooling in Hedemora and Säter

Boman, Johan January 2016 (has links)
Hedemora Energi produces and distributes district heating in Hedemora and Säter. It is during the summer in these cities, as in the rest of the country, a low heating demand. By offering its customers district heating driven absorption cooling, this could be a way to satisfy more requests while being able to sell more heat and better use the available capacity.  In this thesis the cooling potential in Hedemora and Säter is calculated. Furthermore, the impact of integrated absorption chillers on district heating production, as well as absorption cooling profitability for Hedemora Energi is investigated. Simulations and calculations show that the system need to be adjusted for absorption cooling by increasing the supply temperatures during the hours that they are below the requirements of the absorption chillers. In addition, the adjustments cause raised return temperatures and altered flows in the network. This results in increased fuel costs and heat losses, reduced flow revenues and reduced heat supplies from flue gas condensers. Despite this, the economic results are positive for all cases. For example, over 44 thousand SEK in annual profit after integration of absorption chillers, producing 422 MWh of cooling in Skönvik, Säter.

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