Dissertations / Theses on the topic 'Heating'
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Fredriksson, Victor, and Bane Gluhajic. "Heating systems in small houses : A comparison between geothermal heating and district heating." Thesis, KTH, Byggteknik och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-253799.
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District heating and geothermal heating are in present times two established heating systems that are often compared against each other. The purpose of this work is to describe which factors influence the choice of heating system during the planning stage and what the costs are for each system. In this paper, a typical house model has been developed and used as a basis for the comparison of both systems. The comparison has been made in the form of energy calculations in the energy calculation program BV2, where heat requirements and regulatory requirements for energy performance have been compared in different geographical areas in Sweden. Furthermore, cost calculations have been carried out based on the energy calculations' results, where investment costs and annual costs have been set against each other. The result of the work shows how the measurement of energy performance differs from the actual amount of purchased energy due to geographical conditions. In the southern parts of Sweden, where the geographical correction factor is below 0, consumers are penalized by raising the primary energy number, unlike the northern parts where the primary energy number is instead lowered. Based on the cost calculations, it can be concluded that district heating, when available, is more economically advantageous in the short term. Geothermal heating on the other hand is a more profitable alternative in the long run.Fjärrvärme och bergvärme är idag två etablerade värmesystem som ofta ställs mot varandra. Syftet med det här arbetet är att redogöra vilka faktorer som påverkar valet av värmesystem under projekteringsstadiet och vilka kostnaderna som finns för respektive system. I arbetet har en typisk husmodel tagits fram och använts som grund för jämförelsen av båda systemen. Jämförelsen har dels gjorts i form av energiberäkningar i energiberäkningsprogrammet BV2 där värmebehov och myndighetskrav på energiprestanda har jämförts i olika geografiska områden i Sverige. Vidare har kostnadsberäkningar genomförts utifrån energiberäkningarnas resultat där investeringskostnader och årliga kostnader har ställts mot varandra. Resultatet av arbetet visar hur måttet på energiprestanda skiljer sig från den faktiska mängden köpt energi på grund ut av geografiska förhållanden. I de södra delarna i Sverige där den geografiska korrigeringsfaktorn understiger 0 straffas konsumenter genom att primärenergitalet höjs, till skillnad mot de norra delarna där primärenergitalet istället sänks. Utifrån kostnadsberäkningarna kan man dra slutsatsen att fjärrvärme, när den finns tillgänglig, är mer ekonomiskt fördelaktigt på kort sikt. Bergvärme å andra sidan är ett mer lönsamt alternativ på lång sikt.
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Золотова, Світлана Григорівна, Светлана Григорьевна Золотова, Svitlana Hryhorivna Zolotova, and M. O. Kruglyak. "Heating systems." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/13442.
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Put, Joris. "The European District Heating Database and Mapping European District Heating Systems." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15114.
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Sultan, Sahira. "Cost Evaluation of Building Space Heating; District Heating and Heat Pumps." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-37137.
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Climate change and energy efficiency has become a matter of concern in recent times; therefore, energy efficiency of buildings has drawn major attention. According to the European Commission, EU countries must improve energy efficiency of existing buildings by retrofitting and renovating the buildings. A case study of a renovated commercial building is considered in this degree project. A model of the building is developed in the IDA Indoor Climate and Energy (IDA ICE) software. The model is then augmented to include renovations in the building. Further, the model is simulated in IDA ICE before and after renovations to investigate the impact of renovations on energy consumption of the building for one year. The simulation results indicate peak demands of district heating that occur in the coldest days of the year. The peak demands of energy are expected to increase the district heating cost because they serve as a basis for new pricing model introduced by the energy providers. Hence, it is important from the customer point of view to reduce the peak loads for cost shavings. The project work also provides an insight into the alternative source of energy such as heat pumps to reduce the peak load demands of district heating.
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Martín, Segura Guillermo. "Induction heating converter's design, control and modeling applied to continuous wire heating." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/83346.
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Induction heating is a heating method for electrically conductive materials that takes advantage of the heat generated by the Eddy currents originated by means of a varying magnetic field. Since Michael Faraday discovered electromagnetic induction in 1831, this phenomena has been widely studied in many applications like transformers, motors or generators' design. At the turn of the 20th century, induction started to be studied as a heating method, leading to the construction of the first industrial induction melting equipment by the Electric Furnace Company in 1927.
At first, the varying magnetic fields were obtained with spark-gap generators, vacuum-tube generators and low frequency motor-generator sets. With the emergence of reliable semiconductors in the late 1960's, motor-generators were replaced by solid-state converters for low frequency applications.
With regard to the characterization of the inductor-workpiece system, the first models used to understand the load's behavior were based on analytical methods. These methods were useful to analyze the overall behavior of the load, but they were not accurate enough for a precise analysis and were limited to simple geometries. With the emergence of computers, numerical methods experienced a tremendous growth in the 1990's and started to be applied in the induction heating field. Nowadays, the development of commercial softwares that allow this type of analysis have started to make the use of numerical methods popular among research centers and enterprises. This type of softwares allow a great variety of complex analysis with high precision, consequently diminishing the trial and error process.
The research realized in last decades, the increase in the utilization of numerical modeling and the appearance and improvement of semiconductor devices, with their corresponding cost reduction, have caused the spread of induction heating in many fields. Induction heating equipments can be found in many applications, since domestic cookers to high-power aluminum melting furnaces or automotive sealing equipments, and are becoming more and more popular thanks to their easy control, quick heating and the energy savings obtained.
The present thesis focuses on the application of induction heating to wire heating. The wire heating is a continuous heating method in which the wire is continuously feeding the heating inductor. This heating method allows high production rates with reduced space requirements and is usually found in medium to high power industrial processes working 24 hours per day.
The first chapters of this study introduce the induction heating phenomena, its modeling and the converters and tanks used. Afterwards, a multichannel converter for high-power and high-frequency applications is designed and implemented with the aim of providing modularity to the converter and reduce the designing time, the production cost and its maintenance. Moreover, this type of structure provides reliability to the system and enables low repairing times, which is an extremely interesting feature for 24 hours processes.
Additionally, a software phase-locked loop for induction heating applications is designed and implemented to prove its flexibility and reliability. This type of control allows the use of the same hardware for different applications, which is attractive for the case of industrial applications. This phase-locked loop is afterwards used to design and implement a load-adaptative control that varies the references to have soft-switching according to load's variation, improving converter's performance.
Finally, the modeling of a continuous induction wire hardening system is realized, solving the difficulty of considering the mutual influence between the thermal, electromagnetic and electric parameters. In this thesis, a continuous process is modeled and tested using numerical methods and considering converter's operation and influence in the process.
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Song, Jingjing. "Restructured district heating price models and their impact on district heating users." Licentiate thesis, Mälardalens högskola, Framtidens energi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-34779.
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District heating (DH) is considered to be an efficient, environmentally friendly and cost-effective method for providing heat to buildings, since electricity is usually co-generated in biomass fuelled combined heat and power (CHP) plants. This gives it an important role in the mitigation of climate change. Swedish district heating companies are currently facing multiple challenges, and are in urgent need of new price models to increase transparency and maintain their competitiveness. This thesis describes a survey carried out to understand the structure of the present price models and subsequently proposes and compares two restructured price models with the most commonly used price model. This work also investigates the impact of restructured price models on users who would encounter a significant cost increase if the restructured price models were to be introduced. The district heating costs of different price models are compared with three alternative technical solutions. The results show that price models based on the consumption pattern of users can reflect district heating companies’ cost structure. Meanwhile, adopting a pricing strategy based on users’ consumption patterns increased the incentives to reduce the peak load. Consequently, users with high load factor (flat consecutive load curve) were able to reduce costs whereas users with low load factor (steep consecutive load curve) faced possible cost increases, when the load demand cost was changed to daily or hourly peak demand based methods. Further, the most economically preferable option for the invested district heating user was to combine district heating with direct electrical heating or with a ground source heat pump.Fjärrvärme anses som ett effektivt, miljövänligt och kostnadseffektivt sätt för att leverera värme eftersom kraftvärme blir vanligare i fjärrvärmesystem, där elektricitet produceras tillsammans med värme. Den spelar en viktig roll i att begränsa klimatförändringen. Svenska fjärrvärme företag står inför flera utmaningar nu för tiden, och är i akut behov av nya prismodeller för att öka öppenheten och behålla konkurrenskraften. I denna avhandling, genomfördes en undersökning för att ta reda på strukturen av de nuvarande prismodellerna. Därefter föreslogs två omstrukturerade prismodeller, vars påverkan på kostnaden av fjärrvärme konsument analyserades jämför med den nuvarande modellen. Detta arbete undersökte också effekten av omstrukturerade prismodeller på konsument som skulle drabbas på signifikant kostnadsökning i samband med införande prismodeller. Kostnaden av fjärrvärme under olika prismodeller har också jämförts med tre olika tekniska lösningar. Resultatet visade att prismodeller som baserar sig på konsuments förbrukningsprofil kunde återspegla fjärrvärme företagens kostnadsstruktur; Samtidigt medförde prissättningsstrategi baserad på användarens förbrukningsprofil högre incitament för att minska spetseffekt. Följaktligen kommer att konsumenter med stabila konsumtionsprofiler att spara kostnader, medan konsumenter med spetsiga konsumtionsprofiler kommer att drabbas av kostnadsökning. Och för den investerade fjärrvärme konsument, den ekonomiska bättre val var att kombinera fjärrvärme med elpanna eller bergvärmepump.
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Netterberg, Hanna, and Isabel Isaksson. "District Heating in Slough." Thesis, Halmstad University, School of Business and Engineering (SET), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2638.
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District heating through the Swedish model has proven to be an environmental and financially beneficial solution for heating. By reusing energy resources that normally would be wasted con-tributes district heating in an effective way to the society’s energy consumption. Today district heating stands for more than fifty percent of the heat supply to the Swedish residential and service sector buildings. The long tradition in the area has generated knowledge and experiences that to-day are applicable to other countries that are looking for more environmental conscious heating alternatives.
The goal and purpose with this thesis has been to use the Swedish knowledge gained in district heating and apply them in United Kingdom, where district heating currently comprise a low pro-portion of the total energy supply. Through an analytical method, the effective width (ground area/trench length) has been calculated for several city districts in Halmstad and Göteborg. This material has been used to decide the distribution costs depending on different charicaristic num-bers and by so the capital cost for district heat distribution has been estimated for some selected city districts in Slough, United Kingdom.
The result indicates that the effective width can be constant, although this cannot be verified due to possible noice in the data. The capital cost for Slough has shown being slightly higher than the estimated capital cost in the Swedish city districts. During the work of this thesis, differences in the residential living structure in respective country have been identified, which can be a contrib-uting explaination to the higher capital cost in Slough. Though the results still supports the in-crease in usage of district heating in United Kingdom, if low cost heat is available.
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Jannesson, Johan. "Seat heating smart algorithm." Thesis, University West, Department of Technology, Mathematics and Computer Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-338.
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The goal of this project was to build a model and a controller for the seat heater and steering wheel heater on the SAAB cars. SAAB manufactures two different car models 9-3 and 9-5. The goal is to control the seat heater in both car models without any temperature sensor in the seat, this due to cost reduction. Several tests have been carried out booth in climate chambers and during road tests. These tests have in the end lead to a mathematical model for the temperature dependence and this model has been used to design an open loop controller for the seat heater.
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Skytt, Johanna, and Elina Järkil. "Solar heating in Colombia." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-18094.
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This report describes the process of a thesis implemented in Colombia concerning solar energy. The project was to install a self-circulating solar heating system, as well as creating exchange of knowledge regarding renewable energy. One of the two major goals of the project was to achieve a functioning solar heating system in Timbio, a village outside the city of Popayán in south west Colombia. The purpose was to use the free power from the sun and show people how to use it in a way that is not complicated or too expensive. The second major goal was to hold workshops about renewable energy in general, and solar energy in particular. The preparatory work started in October 2010 by concretizing the project, applying for scholarships and establishing necessary contacts; both in Colombia and Sweden. Research and correspondence continued throughout 2011, along with the search for finance from companies and funds to cover the project costs. The implementation took approximately three months and was finished in April 2012. However, the project was limited due to time scale and financial resources. The project was successful; a functioning solar heater and workshops. The aim to arise interest for renewable energy is fulfilled plus the aim to show how to use solar energy in a practical and useful way.Denna rapport beskriver processen av ett examensarbete som behandlar solenergi, implementerat i Colombia. Projektet innebar en installation av en självcirkulerande solvärmeanläggning, och även kunskapsutbyte om förnybar energi. Ett av de två huvudmålen var att installera en fungerande solvärmeanläggning i byn Timbio utanför staden Popayán i sydvästra Colombia. Syftet var att använda gratis energi från solen och visa människor hur man kan använda energin på ett inte alltför komplicerat eller dyrt sätt. Det andra huvudmålet var att hålla workshops om förnybar energi i allmänhet och solenergi i synnerhet. Förberedelserna började i oktober 2010 genom konkretisering av projektet, stipendieansökningar och skapandet av nödvändiga kontakter; i Colombia och Sverige. Efterforskningar och korrespondens fortsatte under 2011 samtidigt som finansiering till projektet söktes från företag och fonder. Installationen tog ungefär tre månader och färdigställdes i april 2012. Projektet begränsades av tillgänglig tid och ekonomiska resurser. Projektet blev framgångsrikt; en fungerande solvärmeanläggning och lyckade workshops. Målet att väcka intresse för förnybar energi uppfylldes, även målet att visa hur solenergi kan användas på ett praktiskt och användbart sätt.
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Johansson, Christian. "Towards Intelligent District Heating." Licentiate thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00467.
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A district heating system consists of one or more production units supplying energy in the form of heated water through a distribution pipe network to a multitude of consumers. District heating systems come in a range of different forms and sizes; from small independent systems within industrial estates or university campuses to large city-wide systems supplying millions of consumers with heating and hot water. The geographically dispersed layout of district heating systems suggest that they are suitable for distributed optimization and management. However, this would imply a transition from the classical production-centric perspective normally found within district heating management to a more consumer-centric perspective. In this work we use multi-agent based systems in order to implement distributed policies for operational planning within district heating systems. We also develop models for simulating the dynamics of district heating systems in order to evaluate those policies and their use in computer-based demand side management approaches for improving operational planning and resource management. These policies are then implemented in real world industrial settings and their performance, as well as implementation issues, are analysed and evaluated. It is shown that distributed policies can lead to significant benefits compared to current schemes with respect to energy usage and heat load management at an operational level.
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Gudiksen, Boris V. "The coronal heating problem." Doctoral thesis, Stockholm : Institutionen för astronomi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-32.
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Felgate, G. B. "Conservatories and domestic heating." Thesis, University of Leeds, 1987. http://etheses.whiterose.ac.uk/648/.
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Passive solar gains to buildings in North European Climates can be significant and an investigation is made into the effect of orientation upon solar gains based upon known weather data. The conservatory is a particularly useful collector because of its inclusion to existing houses and its desirability to the householder for reasons other than solar collection. A conservatory was adapted and monitored. A computer model was written. The behaviour of the conservatory was examined for various criteria. The possibility of inclusion of a conservatory into houses in the existing housing stock was examined. The effect of occupancy on heating demand and solar delivery was reviewed and the likely overall energy saving was examined. A new house system was developed including the use of a first floor concrete slab and a gas warm air heating unit. A concrete floor slab was cast to examine its storage potential. A preliminary design for the heating system of the new houses was undertaken.
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Haq, Z. U. "Hypersonic vehicle interference heating." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336171.
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de, Alwis Ajith Priyal. "Ohmic heating of foods." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357722.
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Lee, Kai Yan. "Heating the early Universe." Licentiate thesis, Stockholms universitet, Institutionen för astronomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-114178.
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Johansson, Christian. "On Intelligent District Heating." Doctoral thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00587.
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Intelligent district heating is the combination of traditional district heating engineering and modern information and communication technology. A district heating systemis a highly complex environment consisting of a large number of distributed entities, and this complexity and geographically dispersed layout suggest that they are suitable for distributed optimization and management. However, this would in practice imply a transition from the classical production-centric perspective normally found within district heating management to a more consumer-centric perspective. This thesis describes a multiagent-based system which combines production, consumption and distribution aspects into a single coherent operational management framework. The flexibility and robustness of the solution in industrial settings is thoroughly examined and its performance is shown to lead to significant operational, financial and environmental benefits compared to current management schemes.
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Martin, Guillaume. "District Heating Networks Design." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264257.
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District heating networks are a solution to decrease the amount of CO2 emission in the atmosphere and a mean to increase the share of renewable energy in the energy mix. This degree project, conducted at Engie Réseaux, investigates the best options to design them. The challenges and the constraints of their design will be developed and the tools created to achieve it will be presented. This thesis exposes the major climatologic, economic, and energetic parameters to take into account when designing a network and shows the methodology used in these three fields.Fjärrvärmenät är en lösning för att minska mängden koldioxidutsläpp i atmosfären och ett medel för att öka andelen förnybar energi i energimixen. Detta examensarbete, utfört på Engie Réseaux, undersöker de bästa alternativen för att designa dem. Svårigheterna och begränsningarna i deras utformning kommer att utvecklas och de verktyg som skapats för att uppnå det kommer att presenteras. Denna avhandling visar de viktigaste klimatologiska, ekonomiska och energiska parametrarna att ta hänsyn till vid utformning av ett nätverk och visar den använda metodiken.
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Stene, Jørn. "Residential CO2 Heat Pump System for Combined Space Heating and Hot Water Heating." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-382.
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Carbon dioxide (CO2, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO2 heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO2 heat pump systems for combined space heating and hot water heating – so-called integrated CO2 heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems..
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Ruan, Wenbo. "Energy survey on replacing a direct electrical heating system with an alternative heating system." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26915.
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With the ever-growing energy demand that world is currently going through and the danger of climate change around the corner, wagering in renewable energy seems to be the right path to create a more smart and green future. Sweden has put great effort on decreasing its dependency on oil, in fact in 2012 more than 50 % of its electricity came from the renewable source and has a plan in making it 100 % in 2040. However, when it comes to heating systems Sweden depends greatly on district heating, and situations which buildings are located outside the district heating system’s reach is not uncommon, hence for those buildings, other options such as solar power or heat pumps are considered. Many buildings located in Skutskär suffer from the problem stated above. The particular building analyzed in this thesis uses electrical radiator and furnace as sources of heat, which implies high energy uses and financial expenses. For this reason technical and financial analysis of using each alternative system for a single family house located in Skutskär had been done. Using solar powered system is deemed to be quite ineffective, as Sweden has poor solar radiation. In order to compensate the poor sun hours during the winter, 51 photovoltaic (PV) panels or 19 solar thermal panels would be required. This high initial investment needs long period of time in order to be profitable, 15 years for solar thermal system and 21 years for solar PV system. On the other hand, the results from the heat pumps are quite satisfactory, the fastest payback period is around 4 years. This is achieved by using air source heat pump (ASHP), the annual saving in this case is three times higher than using solar photovoltaic panels, making the usage of ASHP more attractive than any solar energy system. However, when annual saving is concerned, the ground source heat pump (GSHP) system is capable of generating even higher saving, but the initial investment is significantly higher, extending the payback period to 6 years.
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Aoun, Nadine. "Modeling and flexible predictive control of buildings space-heating demand in district heating systems." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC104.
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La gestion de la demande en chauffage des bâtiments raccordés à des réseaux de chaleur s'effectue classiquement au moyen d’une courbe de chauffe : lorsque la température extérieure chute, la température de départ de l’eau alimentant le circuit de chauffage interne est relevée. Ce mode de contrôle, appelé régulation par loi d’eau, présente des atouts en termes de simplicité et de robustesse, mais ne tient pas compte de l'inertie thermique du bâtiment et ne permet donc pas une modulation de sa demande. La modulation de la demande en chauffage se définit comme l'action de contrôle consistant à modifier de manière stratégique les conditions de confort thermique dans le cadre d’une optimisation énergétique et/ou économique. Il s’agit d’une brique essentielle du contrôle flexible qui envisage le déplacement des charges et l’effacement des pics pour une meilleure efficacité de production favorisant la pénétration des énergies renouvelables et de récupération.Ces travaux de thèse visent à développer une stratégie de contrôle prédictif et flexible de la demande en chauffage, applicable à grande échelle dans les réseaux de chaleur.Tout d'abord, un simulateur thermique dynamique de bâtiment résidentiel, équipé de radiateurs hydrauliques connectés à une sous-station de réseau de chaleur, est développé. Il permet de définir plusieurs cas d’études de bâtiments représentatifs du parc résidentiel français et constitue l’environnement expérimental virtuel de nos travaux de recherche. Ensuite, une méthodologie permettant d’obtenir un modèle orienté-contrôle et d’ordre réduit de bâtiment avec son système de chauffage est proposée. Elle commence par la définition de la structure du modèle en se basant sur des connaissances physiques, puis consiste en l'identification des paramètres par optimisation méta-heuristique à l'aide des données générées par le simulateur. L'approche d'identification paramétrique évalue la possibilité de réaliser cette tâche en ne s’appuyant que sur des données disponibles au niveau de la sous-station, notamment en s’interdisant d’utiliser des mesures de température intérieure au bâtiment, donnée à caractère personnel présumée indisponible à grande échelle pour des raisons techniques, économiques et juridiques. Enfin, la stratégie de contrôle prédictif est implémentée. Elle permet la planification de la température de départ de l'eau de chauffage en fonction des prévisions météorologiques et des prix de l’énergie. Le contrôleur flexible s’appuie sur un problème d’optimisation linéaire sous contraintes, selon le principe de l’horizon fuyant. Il incorpore les équations linéarisées du modèle d’ordre réduit et calcule le compromis optimal entre coûts énergétiques et inconfort thermique, le degré de flexibilité de la demande en chauffage étant défini par l’intermédiaire de paramètres de réglage dédiésIn District Heating Systems (DHSs), buildings Space-Heating (SH) demand management conventionally relies on a heating curve: when the outdoor temperature drops, the internal SH system supply water temperature is raised. This control mode, referred to as Weather-Compensation Control (WCC), offers widely recognized assets in terms of simplicity and robustness. However, WCC does not account for the building thermal inertia, and consequently, it does not allow modulation of its demand. SH demand modulation is the control action of strategically altering the indoor thermal comfort conditions within an energetic and/or economic optimization framework. It is a key measure in flexible demand control strategies, which seek loads shifting and peaks shaving to allow sustainable commitment of energy resources in favour of renewable power penetration and waste heat recovery.The work presented in this thesis aims at developing a flexible Model Predictive Control (MPC) strategy for SH demand, applicable at large scale in DHSs.Firstly, a thermal dynamic simulator of a residential building with a radiator SH circuit connected to a DHS substation is developed. It allows the definition of multiple case study buildings, well-representative of the french residential stock, and constitutes the virtual experimental environment for our research. Then, a methodology to obtain a control-oriented Reduced-Order Model (ROM) for the building and its SH system is proposed. It starts by defining the ROM structure based on physical knowledge, and proceeds to parameters identification by meta-heuristic optimization using data generated by the simulator. The parametric identification approach evaluates the possibility of carrying out this task by relying solely on data available at the substation level, refraining from using indoor temperature measurements, personal data assumed to be unavailable at large scale for technical, economic and legal reasons. Finally, MPC is implemented to schedule the SH supply water temperature as function of weather forecasts and energy price variations. The flexible controller is designed to solve a constrained linear optimization problem according to the receding horizon principle. It embeds the linearized ROM equations within the problem formulation and makes an optimal trade-off between energy consumption costs and thermal discomfort, the degree of flexibility to modulate SH demand being defined through dedicated tuning parameters
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Lieyuan, Chen, and Liang Jing. "The district Heating in China." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4914.
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Ageyev, Victor. "Heating Tariff System In Donetsk." Thesis, KTH, Industriell ekonomi och organisation (Inst.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52439.
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In different countries, such as Ukraine and Sweden, there have been differences in the way of administrating the systems which dictate the way of living and the way the societies function. Different approaches have been adopted over the time when it came to setting up the rules for how the state´s vital organizations, such as tax administration, health care, police, army, education system and many others should work and function. The idea in many modern countries is the same, but the ways and procedures can differ a great deal from country to country. This applies to the sphere of district heating services as well. The purpose of this thesis is to gain understand with the help of economic theory why heating tariffs are managed in a country that has had transition from plan economy to market economy the way they are, and how the management of heating tariffs could be improved when taking into account the experience of a country with long established market economy. During field studies performed in Sweden and Ukraine, particularly in the city of Donetsk, a comparative analysis of the two heating tariff systems have been performed in order to outline and highlight the differences between them and to answer the main questions of the study. The results include the status report of the situation concerning the district heating tariff systems in Sweden and Ukraine, comparative analysis of the two systems and suggestion on improvements of the district heating tariff system in the city of Donetsk. The outcomes and suggested improvements do not provide the full picture and all the aspects of the situation, due to the fact that more extensive studies, involving larger resources, would have to be conducted in the area. However, the report provides a good starting point for further studies within the field of district heating tariffs in Ukraine and Sweden.
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Walker, John David. "Cage rotor heating at stall." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239375.
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Osman, Maslan Bin Haji. "Rotating magnetoconvection with ohmic heating." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363534.
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Larrecq, Geoffroy. "Heating effects on magnetorheological dampers." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60775.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 50-51).
Over the past decades, scientists and engineers have tried to develop and improve various devices and control systems in order to mitigate and prevent civil structures against external dynamic forces such as strong wind and earthquakes. Indeed, damping devices absorb and dissipate the energy input during an earthquake, for instance and thus make structures safer and stable. Many types of devices are currently used such as viscous, friction or tuned mass dampers; however, one of the most recent promising systems proposed is the Magnetorheological damper (MR damper). Because of their ability to be controlled and to adapt their mechanical properties by varying a magnetic field, their high damping force (200kN), their low energy input required and their simple use and implementation in buildings, MR dampers seem to be suitable and realistic for civil engineering application. However, when they are subjected to external dynamic forces, the temperature increase in the damper device may significantly alter their performances and behaviors. This thesis first presents an overview of different technology control systems and MR damper device properties. Then, several mathematical models are developed and applied to explain the behavior of this class of damper. Finally, a study of the heating effects on MR damper performances incorporated in a real structure (3DOF) will be simulated.
by Geoffroy Larrecq.
M.Eng.
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Hallac, Abdulkadir. "Hybrid methods for microwave heating." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619779.
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Tam, Kuan V. "MHD simulations of coronal heating." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6373.
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The problem of heating the solar corona requires the conversion of magnetic energy into thermal energy. Presently, there are two promising mechanisms for heating the solar corona: wave heating and nanoflare heating. In this thesis, we consider nanoflare heating only. Previous modelling has shown that the kink instability can trigger energy release and heating in large scale loops, as the field rapidly relaxes to a lower energy state under the Taylor relaxation theory. Two distinct experiments were developed to understand the coronal heating problem: the avalanche effect within a multiple loop system, and the importance of thermal conduction and optically thin radiation during the evolution of the kinked-unstable coronal magnetic field. The first experiment showed that a kink-unstable thread can also destabilise nearby threads under some conditions. The second experiment showed that the inclusion of thermal conduction and optically thin radiation causes significant change to the internal energy of the coronal loop. After the initial instability occurs, there is continual heating throughout the relaxation process. Our simulation results show that the data is consistent with observation values, and the relaxation process can take over 200 seconds to reach the final relaxed state. The inclusion of both effects perhaps provides a more realistic and rapid heating experiment compared to previous investigations.
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Amrhein, Andrew Aloysius. "Induction Heating of Aluminum Cookware." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/77400.
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Induction heating has become a popular alternative to other heat sources for stovetop cooking applications due to performance, efficiency, control response, and safety. The main drawback is that extreme difficulty is encountered when trying to head low-resistivity, non-ferromagnetic metals such as aluminum and copper, which are commonly used for cookware in several societies. The lack of ferromagnetic properties, resulting in no hysteresis dissipation, and low resistivity of such metals results in an impractically low resistance reflected through the work coil. The resultant impedance complicates inverter design, as it is too low to be efficiently driven with conventional inverter topologies. The magnitudes of current involved in exciting this impedance also severely impact the efficiency of the coil and resonant components, requiring extreme care in coil design. This work explores various techniques that have been proposed and/or applied to efficiently heat low-resistivity cookware and the associated limitations. A transformer-coupled series-load-resonant topology driven by a full-bridge inverter is proposed as a means of efficiently heating aluminum cookware within practical design constraints. The experimental circuit is built and successfully tested at an output power of 1.66kW. The procedure of optimizing the work coil for improved efficiency is also presented along with the procedure of measuring coil efficiency. An improved circuit incorporating switch voltage detection to guarantee zero-voltage switching is then built in order to overcome limitations of this design.Master of Science
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Samaranayake, Chaminda Padmal. "Electrochemical reactions during ohmic heating." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1070303083.
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Morton, Ashley. "Heating use in UK homes." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25523.
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Within the UK, space heating accounts for 66% of the total domestic energy used. New heating controls may offer a means to reduce this figure and help meet the UK s target of reducing its greenhouse gas emissions by 2050. However these technologies will only save energy if occupants are able to use them effectively. Currently, little is known about how occupants interact with their heating systems, in particular how they use the heating within their home and the reasons behind why it is used a specific way. To investigate further, this thesis presents research which used both qualitative and quantitative methods over two separate studies to uncover why and how households heat their homes and how people use their heating system following the installation of new heating controls. The results identify key drivers which impact how people heat their homes and highlight numerous issues preventing them from using their heating how they wish to. A taxonomy of heating use is presented based on the factors influencing heating use in homes and how those factors impact the use and control of the heating system. Occupants use of new heating controls over a ten month period is presented. Manual interaction with controls is separated from programmed heating schedules showing increased manual use over winter and a reliance on heating schedules during shoulder months. The analysis of measured heating use showed similar findings to larger scale studies, however the demanded set-point temperatures were varied and occupants regularly changed heating schedules throughout winter, indicating some of this complexity may be lost by studies inferring heating use patterns from internal temperature measurements alone. The research presented within this thesis is novel, in developing heating characters based on the factors which influence occupants heating behaviours, by presenting measured heating use, which included measured set-point temperatures, heating schedules and heating use duration. The thesis also presented the complexity of heating use within homes uncovered through use of mixed methods.
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Swing, Gustafsson Moa. "The impact on the energy system of heating demands in buildings : A case study on district heating and electricity for heating in Falun, Sweden." Licentiate thesis, Mälardalens högskola, Framtidens energi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-34255.
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Tonhammar, Anders. "Solar District Heating : The potential of a large scale solar district heating facility in Stockholm." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219248.
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As a part of Fortum's vision of a future Solar Economy, a feasibility study of a Solar District Heating facility was conducted. The focus of this study was to determine the technical, economic and environmental potential of a Solar District Heating facility, combined with a seasonal thermal storage, in the district heating network in Stockholm. Three different cases have been studied. The cases differ on the size of the available land area, on what type of storage technology utilized and if excess heat from different production facilities in the network is included or not. The results indicate that it is technically possible to implement a Solar District Heating facility in Stockholm, no obvious limitations in the network has been identified. The thermal storage should preferably be charged throughout the year and be discharged during December to March. The economic results indicate that none of the studied cases are economically feasible without any subsidies, increased revenues or other reductions of initial investment costs. The most economically beneficial system configuration was to utilize a smaller land area for solar collector installations, include excess heat from local production facilities and to utilize existing rock caverns and infrastructure in the area. The Solar District Heating facility could decrease the climate impact and the net primary energy use compared to the production of a biofuel production facility, but a further study is needed.
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Lindgren, Nicolas, and Karl Brogren. "Production optimization for district heating : Short-term planning of district heating grid in Gävle, Sweden." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-44268.
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Energy systems with a high portion of renewable energy from wind and solar power can suffer from fluctuations in production due to weak winds or cloudy weather, which may affect the electricity price. When producing heat and power in a combined heat and power plant, an additional heat storage tank can be used to store the heat surplus which is obtained when the power production is high, and the heat demand is low. To optimize heat and power production economically, short-term planning can be applied. Short-term planning covers the production in the near future of 1-3 days. The optimization in this degree project is based on the district heating production, which means that the heating demand always needs to be fulfilled. The district heating production is based on the weather. Therefore a suitable period for simulation is three days due to the accuracy of the weather forecasts are reasonable. The optimization is performed on the district heat system in Gävle, Sweden. The system comprises several different production units, such as combined heat and power plants, backup plants, and industrial waste heat recovery. Two different models are made, one using linear programming and one using mixed integer non-linear programming. The model stated as a linear programming problem is not as accurate as of the one stated as a mixed integer non-linear programming problem which uses binary variables. Historical input data from Bomhus Energi AB, a company owned together by the local heat and power supplier Gävle Energi AB and the pulp and paper manufacturer BillerudKorsnäs AB, was given to simulate different scenarios. The different scenarios have various average temperatures and in some scenarios are there some issues with the pulp and paper industry affecting the waste heat recovery. In all scenarios is the heat storage tank charged when the demand is low and then discharged when the demand increases to avoid starting some of the more expensive backup plants if possible. The simulation time varies a lot between the two approaches, from a couple of seconds to several hours. Particularly when observing scenarios with a rather high demand since the backup generators use binary variables which take a lot of time to solve.
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Stene, Jørn. "Residential CO2 Heat Pump System for Combined Space Heating and Hot Water Heating." Doctoral thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-382.
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Carbon dioxide (CO2, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO2 heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO2 heat pump systems for combined space heating and hot water heating – so-called integrated CO2 heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems..
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Kamal, Majd. "Potential for low temperature district heating system : Integrating 4th generation district heating system with existing technology." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-35816.
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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.
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Kunz, Jakob. "Dynamic behavior of district heating systems /." [S.l.] : [s.n.], 1994. http://library.epfl.ch/theses/?nr=1234.
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Magnusson, Erik, and Johan Schedwin. "Development of solar water heating system." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-4428.
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This report includes development of an already designed solar water heater. The product shall be constructed in a way that it will suit a manufacturing line in Kampala, Uganda. To find the most suitable design for each area a research was carried out which included study visits, interviews and background reading. It provided the following results: Regarding the attachment of in- and outgoing pipes from the water tank many methods were taken into consideration and it was found that the best and most suitable way for this case is to weld the fittings using a weld robot. Regarding the fitting of the acrylic, a suitable solution is to make a flange when vacuum forming the plastic casing to further support the design. This could also be used to waterproof the case by using a sealing material. A suggestion of using pre-molded PU-foam is also presented. Regarding the ability to open the case for maintenance, two solutions were recommended. Either the use of spire clips or having the clips integrated into the casing. Regarding the calculation of material usage when deep drawing the tank and collector, it is possible to do a reasonably accurate assumption. The complicated design in this product makes the estimation less accurate. It is recommended that test draws are done and often the machine producer has more precise numbers. Regarding the coloring of the collector; chemical coloration is not possible on a galvanized surface. The method used is painting, either with powder coating or with wet paint.
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Mao, Jie. "Joule heating in magnetohydrodynamic duct flows." Thesis, Coventry University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492355.
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Joule heating effect in liquid metal magnetohydrodynamic (MHD) flows has been investigated numerically with reference to self-cooled liquid metal blankets for tokamaks. To investigate main effects associated with the Joule heating, pressure-driven Hartmann flow, fully developed MHD flow in a rectangular duct and developing MHD duct flow in a rectangular duct are studied in detail. An external, strong magnetic field is applied in the direction transverse to the flow. The walls are both electrically and thermally conducting, while the outside surface of the walls is thermally insulating. At the entrance into the duct the temperature is a constant. As the fluid progresses through the duct, the electric currents are induced as a result of MHD interaction. These currents . result in volumetric heating of both the fluid and the walls, and the temperature rises along the flow. As the outside boundaries are thermally insulating, the temperature accumulates within the domain. .. The electric currents are induced in the core, and return via the side layers, Hartmann layers at the walls, and in the walls themselves. If the walls are electrically insulating, the magnitude of the electric currents i~ insufficient to heat up the fluid by more than a few degrees. If the walls are electrically conducting, much stronger currents circulate within the flow. It is shown that in the Hartmann flow and fully developed flow model in rectangular duct with electrically conducting walls, the temperature along the flow at the fluidHartmann wall interface may rise by over 100°C over a distance of about 180 values of the characteristic length, which is roughly the total length of the blanket. This is a sufficiently high value to be taken into account in blanket design. The Joule heating effect in the Hartmann flow, in the fully developed rectangular duct MHD flow and in the three-dimensional rectangular duct MHD flow is compared. It is shown that the Joule heating effect is strongly dependent on the wall conductance ratio, the Hartmann number and the average velocity of the fluid. A detailed investigation of the effect of these parameters on the resulting rise of temperature has been performed. The investigation shows that the Joule heating effect may be a significant factor for the development of the fusion blanket not employing insulating coatings. Finally, the effects to be expected for the electrical conductivity dependent a temperature in duct flows are outlined.
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Lindgren, Jonas. "Numerical modelling of district heating networks." Thesis, Umeå universitet, Institutionen för fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-143896.
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District heating is today, in Sweden, the most common method used for heating buildings in cities. More than half of all the buildings, both commercial and residential, are heated using district heating. The load on the district heating networks are affected by, among other things, the time of the day and different external conditions, such as temperature differences. One has to be able to simulate the heat and pressure losses in the network in order to deliver the amount of heat demanded by the customers. Expansions of district heating networks and disrupted pipes also demand good simulations of the networks. To cope with this, energy companies use simulation software. These software need to contain numerical methods that provide accurate and stable results and at the same time be fast and efficient. At the moment there are available software packages that works but these have some limitations. Among other things you may need to divide the whole network into smaller loops or try to guess how the distribution of pressure and flow in the network looks like. The development in recent years makes it possible to use better and more efficient algorithms for these types of problems. The purpose of this report is therefore to introduce a better and more efficient method than that used in the current situation. This work is the first step in order to replace a current method used in a simulation software provided by Vitec energy. Therefore, we will in this report, stick to computing pressure and flow in the network. The method we will introduce in this report is called the gradient method and it is based on the Newton Raphson method. Unlike with older methods like Hardy Cross which is a relaxation method, you do not have to divide the network into loops. Instead you create a matrix representation of the network that is used in the computations. The idea is also that you should not need to make good initial guesses to get the method to converge quickly. We performed a number of test simulations in order to examine how the method performs. We tested how different initial guesses and how different sizes of the networks affected the number of iterations. The results shows that the model is capable of solving large networks within a reasonable number of iterations. The results also show that the initial guesses have little impact on the number of iterations. Changing the initial guess on the pressure does not affect the number at all but it turns out that changing the initial guess on the flow can affect the number of iterations a little, but not much.
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Brown, Craig R. "Towards generic-optimal domestic heating control." Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/811260/.
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Presently, the uncertainties associated with controlling domestic heating system are managed using rule of thumb or heuristic rule-based controllers. The problems associated with this are: lack of bespokeness and optimality of the control to each unique building, difficulty in comparing technologies due to inconsistent control quality (lack of generality) and the expense of developing controllers for new technologies. In this work, the problem of heating system control is generalised with the intent of developing a generic-optimal controller — one that can control any set of heat sources in any building optimally, alleviating the aforementioned problems. A hybrid intelligent system design methodology is applied in order to develop the (model predictive) controller resulting in two sub-tasks. First, acquiring a model of each heating system — identification must be carried out on-line. Second, delivering optimal control using the model, given constraints. The first is tackled by applying Echo State Networks (ESN’s), whose benefits are that they have universal approximation ability, on-line learning is a recursive linear regression problem (for which the solution even in low precision environments is well understood), that on-line learning can be easily achieved using real feedbacks (network stability is relatively easy to attain) and that they can be easily scaled to systems of varying complexity. The second is tackled by using a global, derivative-free optimiser — meaning that the controller may tackle mixed integer problems and incorporate arbitrary output constraints expressed as penalty functions. A theoretical third problem arises due to the interaction of the learning and optimisation components of the controller. A methodology for tackling this is given. When applied to a simulated monovalent heating system in an unoccupied house (in the absence of user disturbances) consistent control can be achieved. The effective rejection of user disturbances is an outstanding problem and is briefly discussed.
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Marcotte, Michèle. "Ohmic heating of viscous liquid foods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ55357.pdf.
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Yliniemi, Kimmo. "Fault detection in district heating substations /." Luleå : Luleå tekniska universitet, 2005. http://epubl.ltu.se/1402-1757/2005/60/.
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Neale, Antony John. "Heat transfers from district heating pipes." Thesis, Cranfield University, 1987. http://dspace.lib.cranfield.ac.uk/handle/1826/4546.
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Experimental and numerical investigations were carried out on
air-filled cavities containing heated inner cylinders.
The effect of varying the position of radial spacers on a
single cylinder was studied. It was concluded that for central
positioning of the cylinder within the cavity. the rate of
heat-transfer was minimised at a radial spacer angle of 480
(measured from the vertically downwards radius vector). When
the cylinder was positioned at displacement ratio of 0.7, the
rate of heat-transfer was minimised at a corresponding spacer
angle of 520. The corresponding reductions in the total rate
of heat-transfer were found to be 25% and 31% less than that
obtained for the system with no spacers at a cylinder
displacement ratio of zero.
Following this research investigation, the behaviour of a
two-pipe arrangement, consisting of a hot supply and cooler
return pipe within a rectangular sectioned cavity, was
studied. Eccentric positioning of both supply and return pipes
showed that minimum rates of heat-transfer occur at supply and
return pipe displacement ratios of 0.45 and -0.33
respectively. This value of heat-transfer is approximately 20%
less than that obtained for a system where supply and return
pipe displacement ratios are 0.7 and zero respectively.
As experimental testing has proved to be excessively time
consuming (e. g. due to having to wait until a steady-state
ensued before measurments were taken) and laborious, a
finite-element numerical model was developed and used to
predict the heat-transfer between a heated inner cylinder and a
cooled outer square duct.
This study investigated eccentricity effects on the rate of
heat-transfer for different ratios of duct height to cylinder
radius. Solutions were obtained for Rayleigh numbers 1 to 300
and optimal pipe eccentricity for minimum heat-transfer was
predicted. These predictions were in good agreement with
previous experimental results.
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Soderlund, Matthew Roger. "Congeneration dedicated to heating and cooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17672.
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Payant, Rebecca. "The self-heating of sulphide mixtures." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96870.
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Under certain conditions of moisture and oxygen, sulphides can spontaneously heat, known as self-heating or pyrophoric behaviour. In this thesis the hypothesis that galvanic interaction between some sulphides can promote self-heating is tested. Galvanic interaction is controlled by rest-potential difference between the minerals and the surface area of contact (particle size). In order of decreasing rest-potential, four sulphides were tested: pyrite, chalcopyrite, sphalerite and galena. Two series of samples consisting of mixtures of two sulphides each representing a mass fraction of 50 % were run in standard self-heating tests. The first series comprised five mixtures were prepared, two with low rest-potential difference (pyrite-chalcopyrite and chalcopyrite-sphalerite) and three with high rest-potential difference (pyrite-galena, chalcopyrite-galena and pyrite-sphalerite). The second series was performed on a pyrite-sphalerite mixture at four particle sizes (80 % passing 850 μm, 300 μm, 75 μm and 38 μm). The first series showed that the individual sulphides and the mixtures of low rest-potential difference did not self-heat but the mixtures of high rest-potential difference did self-heat. The second series showed that self-heating increased inversely with particle size (increasing specific surface area) and that it was the fineness of the pyrite (the high rest-potential sulphide) that governed the self-heating effect, indicating the rate-limiting reaction is reduction at the more noble pyrite (cathodic mineral). The increase in self-heating with high rest-potential difference and increasing particle fineness supports the hypothesis that galvanic interaction contributes significantly to sulphide self-heating. A possible mechanism based on the H2S hypothesis is proposed. The understanding gained will be of interest to those involved in storage, shipping and disposal of sulphide mineral mixtures.Sous certaines conditions d'air et d'humidité, les sulfures peuvent s'auto-échauffer, et dans un cas extrême, subir une auto-combustion. Le présent mémoire étudie l'hypothèse qu'un effet galvanique entre certains sulfures pourrait promouvoir l'auto-échauffement. L'effet galvanique est contrôlé par la différence de potentiel de corrosion (ΔE) et l'aire de surface en contact (granulométrie). En ordre décroissant de potentiel de corrosion, les quatre sulfures étudiés sont: la pyrite, la chalcopyrite, le sulfure de zinc et la galène. Deux séries d'échantillons ont été soumises à des tests standards d'auto-échauffement. Les séries se composaient de mélanges de deux sulfures, chaque sulfure représentant une fraction massique de 50 %. Dans la première série, cinq mélanges ont été préparés, deux avec une différence de potentiel de corrosion de 0,1 volt (pyrite-chalcopyrite et chalcopyrite-sulfure de zinc) et trois d'un potentiel de corrosion > 0,2 volt (pyrite-galène, chalcopyrite-galène et pyrite-sulfure de zinc). Dans la deuxième série, un mélange de pyrite-sulfure de zinc à quatre granulométries différentes (80 % passant 850 μm, 300 μm, 75 μm et 38 μm) a été étudié. Dans la première série, les sulfures individuels et les mélanges possédant une différence de potentiel de corrosion de 0,1 volt ne se sont pas auto-échauffés, mais les mélanges ayant une différence de potentiel de corrosion de > 0,2 volt se sont auto-échauffés. La deuxième série étudiée montre que l'auto-échauffement augmente de façon inversement proportionnelle à la grosseur des particules (aire de contact plus grande) et que la finesse de la pyrite (sulfure au potentiel de corrosion le plus élevé) gouverne l'effet galvanique, indiquant que la réaction cinétiquement limitante est la réduction sur le sulfure le plus noble, donc la pyrite (la cathode). L'augmentation d'auto-échauffement dû à la différence de potentiel de corrosion > 0,2 volt et une granulométrie fine mettent en évidence l'hypothèse qu'un effet galvanique contribue d'une façon significative à l'auto-échauffement des sulfures. Un mécanisme basé sur l'hypothèse de l'acide sulfhydrique (H2S) est suggéré. Les résultats seront d'intérêt pour les personnes responsables de l'entreposage, du transport et de l'élimination de mélanges de sulfure.
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Graham, W. J. "Adaptive control of wet heating systems." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370317.
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Nkansah-Boadu, Frank. "Delectric heating pretreatment of organic slurries." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45627.
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Ngabe, Barnabe. "Physical chemistry of sulphide self-heating." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123024.
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ABSTRACTA prerequisite step towards building a self-heating (SH) model for sulphide materials is the determination of physico-chemical parameters such as the specific heat capacity (Cp), and the energy of activation (Ea). The specific heat capacity of one copper and three nickel concentrates was determined over the temperature range 50 to 80oC in the presence of 6% moisture using the self-heating (SH) apparatus and confirmed by Drop Calorimetry. The Cp values from both techniques were comparable. The Cp values were similar for all concentrates increasing from 0.4 to 1.4 Jg-1K-1 as temperature increased from 50 to 80oC. From the Cp values, the enthalpy change (ΔH), the entropy change (ΔS) and the Gibbs free energy change (ΔG) for self-heating, were determined. The ΔG was negative, demonstrating that self-heating of the concentrates was spontaneous.Using the self-heating apparatus the, activation energy (Ea) was determined for the Ni-and Cu-concentrates and for pairs of sulphide minerals. The Ea ranged from 22 to 30 kJ.mol-1, implying a common reaction. Further support for a common reaction is the strong positive correlation between Ea and ln(QA/Cp) where Q (J.kg-1) is the heat of reaction causing self-heating and A the Arrhenius pre-exponential factor (s-1). Comparing to literature, the Ea values correspond to partial oxidation of hydrogen sulphide, supporting the contention that H2S may be an intermediate product in the self-heating of sulphide minerals. A positive relationship between Ea and the rest potential difference (ΔV) for the sulphide pairs and a negative relationship between Cp and ΔV were demonstrated which support a connection between self-heating and the galvanic effect.RESUMÉLa réalisation d'un modèle mathématique de l'auto-échauffement des concentrés sulfurés de nickel et de cuivre et des mélanges des minerais sulfurés, enjoint à la détermination des paramètres physico-chimiques tels que les capacités de chaleur spécifiques (Cp), et les énergies d'activation (Ea). Les capacités de chaleur spécifiques d'un concentré de cuivre et de trois concentrés de nickel contenant 6% d'humidité, ont été déterminées par utilisation d'un instrument de mesure de vitesse d'auto – échauffement et validées par la calorimétrie de chute dans l'intervalle de températures allant de 50 à 80oC. Les Cp (0.4 à 1.4 Jg-1K-1) obtenues sont similaires pour tous les échantillons. A partir des valeurs des Cp, les variations de l'enthalpie (ΔH), l'entropie (ΔS) et de l'énergie libre de Gibbs (ΔG) de l'auto échauffement ont été déterminées. La valeur négative de ΔG confirme le caractère spontané de l'auto échauffement des minerais sulfurés.Les énergies d'activation (Ea) pour l'auto-échauffement des concentrés de nickel et cuivre et des paires de minerais sulfurés étaient déterminées en faisant usage de l'appareil d'auto-échauffement. Les Ea ainsi obtenues oscillent entre 22 et 30 kJ.mol-1 : Ce qui est suggestif d'une rèaction chimique commune gouvernant l'auto-échauffement de ces matériaux. Ce fait est corroboré par la forte corrélation obtenue entre Ea et ln(QA/Cp) (Q (J.kg-1) est la chaleur de la rèaction chimique responsable de l'auto-échauffement et A (s-1) la constante d'Arrhenius).Ensuite celles-ci sont similaires à celle de l'oxydation partielle du H2S. Il se pourrait, ce faisant, que H2S soit un composé intermediaire lors de l'auto–échauffement des sulfures.Enfin, la corrélation positive entre Ea et la difference de potential (ΔV) dans les paires de minerais sulfurés et celle negative entre Cp et ΔV sont une preuve qu'il existe bel et bien une connection entre l'auto-échauffement et l'effet galvanique.
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Croxford, Ben. "An intelligent, domestic central heating controller." Thesis, University of Westminster, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359206.
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Werner, Burckhardt Christian 1967. "Pipe circularity reformation via line heating." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/91375.
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Thesis (S.M. in Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.Includes bibliographical references (leaves 106-107).
by Christian Werner Burckhardt.
S.M.in Naval Architecture and Marine Engineering
S.M.