Дисертації з теми "Power wastage"
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Nanjappa, Jagdish. "Web-based dynamic material modeling." Ohio University / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1174918633.
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Gibbons, Jonathan S. (Jonathan Scott) 1979, and Stephen V. 1982 Samouhos. "Mobile power plants : waste body heat recovery." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32814.
Повний текст джерелаАнотація:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references.
Novel methods to convert waste metabolic heat into useful and useable amounts of electricity were studied. Thermoelectric, magneto hydrodynamic, and piezo-electric energy conversions at the desired scope were evaluated to understand their role and utility in the efficient conversion of waste body heat. The piezo-electric generator holds the most promise for the efficient conversion of waste body heat into electricity. In the future, this same device could be easily extended into a combustion based power plant. An experimental apparatus investigating the use of magneto hydrodynamics was designed, built, and tested. A room temperature liquid inetal was propelled through a magneto hydrodynamic channel of 4 inches by 0.1875 inches at a rate of 10 mL/s. A 2 T induction field was applied within the channel. However, the results of the analysis did not find the magneto hydrodynamic device to be an effective electric generator at the scale tested.
by Jonathan S. Gibbons and Stephen V. Samouhos.
S.B.
3
Wright, Lee. "Properties of concrete containing desulphurised waste." Thesis, Sheffield Hallam University, 2003. http://shura.shu.ac.uk/20570/.
Повний текст джерелаАнотація:
In the past, the emission of SO[2], NO[x] and CO[2] gasses, as a result of the combustion of fossil fuels within the power industry has been a major contributor to the pollution of the environment. Controls over the last few years have been implemented to combat the effects of air pollution on the environment. One such control is the reduction of sulphur dioxide (SO[2]) from power stations, which is achieved by fitting desulphurisation systems to new and existing installations. At present there are many types of desulphurisation processes available, which produce a variety of wastes that vary in quality and quantity. The majority of processes fit into three main categories, wet, semi dry and dry desulphurisation processes. Desulphurisation systems work by introducing alkaline sorbents, such as limestone, to the SO[2] gasses, either during or after combustion. The limestone reacts with the SO[2] gasses to form new insoluble materials such as gypsum (CaSO[4].2H[2]O). However, semi-dry and dry processes produce wastes that are usually a blend of fly ash and some form of calcium sulphate. The wide variation in chemical, physical and mineralogical properties of the wastes produced hinders their utilisation, because general experimental investigations are only relevant to specific types of wastes. In addition, the wastes can contain large quantities of sulphates, which are normally limited to a few percent in plain cements to regulate setting, and therefore, their initial potential appears limited. The current investigation aims to evaluate the performance of paste, mortar and concrete that contain large quantities of actual and simulated desulphurised wastes. Members of the Copernicus project (1999) provided various desulphurised wastes from Eastern European installations for investigation. Fly ash and gypsum from UK sources were blended in different proportions to simulate desulphurised wastes based on a range of SO[3] contents typically associated with actual desulphurised wastes produced throughout Eastern Europe. Several tests were conducted on paste, mortar and concrete containing actual and simulated desulphurised wastes to investigate basic physical, mechanical and durability properties. These include chemical shrinkage, porosity and pore size distribution, water absorption, length change, compressive strength, and sulphate resistance. The outcomes of investigation were positive in that cement based materials containing high levels of desulphurised wastes were produced, which exhibit physical, mechanical, and durability properties equal or superior to reference cements, and cements containing more common replacement materials such as fly ash and slag. Attempts were made to correlate specific properties such as chemical composition, porosity and pore size distribution, and chemical shrinkage with strength in order to determine the key factors influencing strength development of cement-based materials containing desulphurised wastes. The relationship between SO[3] content and compressive strength of pastes containing simulated desulphurised wastes (FA-G blends) was used to predict the theoretical strength of cement-based materials containing actual desulphurised wastes with reasonable accuracy. Thus reinforcing the decision to evaluate simulated desulphurised wastes due to the diverse nature of desulphurised wastes currently available across Eastern Europe.
4
Blanquart, Fanny. "Perspectives for Power Generation fromIndustrial Waste Heat Recovery." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215985.
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Abuzed, Sami A. Saad. "Photovoltaic power conversion : improvements to maximum power tracking algorithms and the repurposing of waste power supplies in battery charger applications." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/11581/.
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Engelke, Kylan Wynn. "Novel thermoelectric generator for stationary power waste heat recovery." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/engelke/EngelkeK0510.pdf.
Повний текст джерелаАнотація:
Internal combustion engines produce much excess heat that is vented to the atmosphere through the exhaust fluid. Use of solid-state thermoelectric (TE) energy conversion technology is a promising technique to recapture some of the energy lost. The TE effect, discovered in 1821 by Thomas Seebeck, is essentially the solid-state conversion of a temperature gradient into an electric potential. The scope of this work was the design, testing and evaluation of a novel and robust TE generator that is amendable to use in a vast array of convective thermal processes. Seebeck testing of TE elements was combined with thermal/hydraulic and thermoelectric modeling to develop the design of a working prototype system. A proof-of-concept small-scale prototype (SSP) TE generator was built to evaluate concepts intended for the construction of a fully-functional field demonstration prototype (FDP). The SSP was used to evaluate electrical contact integrity, thermal characteristics, various TE materials and the feasibility of using compression-based TE contacts. The SSP featured 9 P/N TE pairs and has thus far produced a maximum open-circuit voltage of 380mV and a maximum electrical power of 1.47W. Knowledge gained from the SSP construction and testing was utilized in the design and fabrication of the FDP. A liquid-cooled Honda ES6500 6.0kW genset was procured to provide a test-bed for the FDP. The primary goal was to power the electric radiator fan with the heat energy contained in its exhaust, thus decreasing the genset's fuel consumption rate. The FDP contained 256 P/N pairs and thus far has produced an open-circuit voltage of 5.5VDC and a maximum power of 8.49W. Replacing the stock muffler reduced fuel consumption by 11.6% whereas removing the fan load reduced it an additional 1.64%. Through the recovery and conversion of wasted thermal energy, the genset's fuel consumption rate was successfully lowered, therefore validating the benefits of secondary TE power systems. The radiator fan of the Honda ES6500 consumes approximately 1% of the overall power output of the genset. Radiator fans in larger gensets can draw as much as 12-16% of their peak output. By recuperating waste heat, substantially higher fuel savings could be achieved.
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Emen, Seyfullah. "Power conditioning for MEMS-based waste vibrational energy harvester." Thesis, Monterey, California: Naval Postgraduate School, 2015. http://hdl.handle.net/10945/45848.
Повний текст джерелаАнотація:
Approved for public release; distribution is unlimitedIncreasing energy needs push industry to build more sustainable and efficient systems. One of the methods to achieve energy efficiency is to feed wasted energy generated by a system itself during operation back to the system. Vibrational energy is one of the most common ambient energy forms in mechanical systems and can be converted into electrical energy with the implementation of piezoelectric energy harvesters. What makes this possible is the piezoelectric effect that some crystals and ceramics with no inversion symmetry show. Piezoelectric materials generate a potential difference when a force is applied and deform under an electric field. Power electronics is used to turn this potential into a usable energy. The amount of power generated by a single piezoelectric energy harvester could be very low, but Microelectromechanical Systems (MEMS) technology makes it possible to have thousands of devices in a very small area. Previously, a MEMS-based piezoelectric harvester for military applications was designed, developed, and tested at NPS. In this thesis, methods to convert the AC voltage output of this device into a DC voltage were investigated to find an efficient method. Because of their higher power needs, multiple devices need to be connected to achieve required power levels for military applications. Microfabrication processes allow for building large number of such devices at the same time. This thesis also studies the possible connections for an array of devices. Connection geometry that will produce the maximum power output for a number of devices is proposed.
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Weerasiri, Udayani Priyadarshana. "A waste heat recovery steam power generation system for ACE Power Embilipitiya (Pvt) Ltd, Sri Lanka." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157832.
Повний текст джерелаАнотація:
In this study, the heat recovery from exhaust gas at the ACE Power Embilipitiya (Pvt) Ltd (APE) in Sri Lanka was conceptually proposed and evaluated. APE has an installed capacity of 100 MW comprising 14 units of 7.5MW medium speed diesel engines fired with heavy fuel oil. There is only a minimum recovery of waste heat in the plant at the moment, only for fuel preheating, whereas waste heat recovery (WHR) boilers of 750kWth are equipped on eight engines. The larger portion of the waste heat is dumped into the environment without being used in any reasonable way. The objective of this work was to design a HRSG system for the remaining six engines to recover maximum possible heat from the exhaust gas and select a suitable steam turbine according to the heat demand capacity of the proposed HRSG, for generating additional power and thus converting the APE plant into a sort of a combined cycle. At the initial stage of the investigation, the amount of recoverable waste heat was estimated by evaluating the known parameters of the engines at fully loaded condition. The maximum theoretical waste heat recovery potential from the exhaust gas stream of one engine was calculated as 9807.87 MJ/h, equivalent to a heat rate of 2724.4 kW. The modelling and optimization of the proposed HRSG was done using the Engineering Equation Solver (EES) software, considering technical and practical limitations such as pinch point temperature difference, approach point temperature difference, terminal temperature difference and sulphur dew point in the stack. A commercially available steam turbine with a power output of 3.579 MW was selected as the optimum steam turbine for the desired conditions, utilising 12884.4 MJ/h of recovered waste energy amounting to 21.89% of the total available energy in the flue gas.
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Chhiba, Chetan. "Titanium alloy powder production from waste metal." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/11989.
Повний текст джерелаАнотація:
Includes abstract.Includes bibliographical references.
Titanium and its alloys are among the most important advanced materials in use today due to attractive properties such as high strength to weight ratio and excellent corrosion resistance. However, the cost of titanium production is high, mostly due to the high cost of extraction. This has led to investigations of potentially lower cost methods such as near-net shape powder metallurgy techniques. One approach, which has the potential of producing the lowest cost powder available, involves converting titanium waste machine turnings to powder using the hydride-dehydride (HDH) process. The focus of this project is directed at this approach where a ball milling process is used to simultaneously hydrogenate and crush the titanium turnings into titanium hydride powder.
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Frykman, Carina. "The Power of Waste : A Study of Socio-Political Relations in Mexico City’s Waste Management System." Thesis, Uppsala University, Department of Cultural Anthropology and Ethnology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7063.
Повний текст джерелаАнотація:
Abstract
It is estimated that up to 2 percent of the population in Third World countries survives on waste in one way or another. In Mexico City alone there exist 15,000 garbage scavengers called Pepenadores. The poverty and marginalization they experience is utterly linked to their work, and while they do much of the hard work their socio-economic situation seems stagnant. This paper explores the complexity of the waste management system in Mexico City which keeps them in this position, and how the current system is a manifestation of the existing symbiosis between the formal and informal sectors of the city.The main characters in the maintenance of this system are the leaders of waste management associations.Their struggle to maintain their powerful positions influences both the system’s relationship to the public sector and determines the socioeconomic situation of the Pepenadores.The paper also analyzes the effects of past efforts to change the system, and how policy changes always seem to work against the Pepenadores. Efforts to help the Pepenadores escape their vulnerable positions can be successful in the short-term, but the existing social structure in Mexico City make any permanent changes difficult to achieve.
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Chabo, Alexander, and Peter Tysk. "Maximum Net-power Point Tracking of a waste heat recovery system." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202206.
Повний текст джерелаАнотація:
Av den frigjorda energin för en lastbils bränsle är omkring 30% i form avspillvärme i avgassystemet. Med implementation av ett spillvärmeåtervinningsystem går det att återvinna en del av den frigjorda energin i form av elektricitet till lastbilens elsystem. Två termoelektriska generatorer använder avgaserna som värmekälla och ett kylmedel som kall källa för att åstakomma en temperaturdifferans i generatorerna. Med hjälp av Seebeck-effekten går det att omvandla temperaturdifferansen till elektricitet och på så sätt avlastas motorns generator vilket medför en lägre bränsleförbrukning. Detta examensarbete innefattar utvecklandet av en funktion som maximerar nettoeffekten utvunnen från systemet. Funktionen som utvecklats är döpt till Maximum Net-power Point Tracking (MNPT) och har som uppgift att beräkna referensvärden som styrningen av systemet skall uppnå för att få ut maximal nettoeffekt. En simuleringmiljö i Matlab/Simulink är uppbyggd för att kunna implementera en kontrollstrategi för styrningen av kylmedlet samt avgasledning via bypass-ventiler. Systemet har blivit implementerat i en motorstyrenhet på en testrack somkommunicerar via CAN där givare så som temperatur och tryck avläses. Systemet har ej blivit implementerat på lastbilen då samtliga fysiska komponenter ej blev färdigställda under examensarbetets gång. En fallstudie genomfördes i simuleringsmiljön och resultaten visade att användningen av en MNPT-funktion tillät upp till 300% ökning av den återinförda nettoeffekten till lastbilens elsystem jämfört med utan användning av kontrollalgoritmer, och upp till 50% ökning jämfört med statiska referensvärden.About 30% of the released energy of a truck’s fuel is waste heat in the exhaustsystem. It is possible to recover some of the energy with a waste heat recovery system that generates electricity from a temperature difference by utilising the Seebeck-effect. Two thermoelectric generators are implemented on a truck and utilises the exhaust gas as a heat source and the coolant fluid as a cold source to accomplish a temperature difference in the generators. The electricity is reintroduced to the truck’s electrical system and thus reducing the load on the electrical generator in the engine which results in lower fuel consumption. This thesis includes the construction of a function that maximises the netpowerderived from the system. The function developed is named Maximum Net Power Point Tracking (MNPT) and has the task of calculating reference values that the controllers of the system must achieve in order to obtain maximumnet-power. A simulation environment has been developed in Matlab/Simulink in order to design a control strategy to three valves and one pump. The system has been implemented on a engine control unit that has been mounted on a test rack. The engine control unit communicates through CAN to connected devices. The system has not been implemented on the truck due that all the physical components were not completed during the time of the thesis. A case study has been conducted and the results proves that the use of an MNPT-function allows up to 300% increase in regenerated net power into the trucks electrical system compared with no control algorithms, and up to 50% compared with static reference values.
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Woo, Pak-wai Jimmy. "The management of flue gas desulphurization waste in Hong Kong /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14723037.
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Björnfot, Karl. "Sustainable Power Production in Chile." Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8388.
Повний текст джерелаАнотація:
Summary
This report is about how Chile can find its way towards a sustainable power production. The two major Chilean electric systems are modeled and optimized by a special optimization program for energy systems called MODEST. The model is then altered so that new sustainable energy sources can be put into the system. If these new energy sources are more economically beneficial they will enter the system. The time period that is modeled is the years 2006 to 2010 and the demand for electricity is rising between these years. 7 different scenarios where the terms for fossil fuels and renewable energies are changed in different ways is tested to see what can be done to introduce more sustainable energy into the system. The different changes include tax on carbon dioxide emissions, subsidies for new sustainable energy sources and limits in carbon dioxide emissions. The results show that:
• Taxes are an ineffective way to get more sustainable energy but can work to reduce emissions. The tax could be used to fund subsidies for cleaner energies.
• Subsidies can work to bring in more sustainable energy and if there is a possibility to use the clean development mechanisms available within the Kyoto protocol. Then it does not have to be subsidies but investments from companies in countries that have signed the Kyoto protocol.
• Waste to energy is the most cost effective new energy source, although it is questionable however this is really a renewable energy source. The author thinks that although it might not be renewable it is certainly sustainable within a foreseeable future.
• A natural gas shortage will have serious effects on the system and should be avoided at least until there are enough alternative fuels available. It is therefore important to continue encourage the development of sustainable power sources.
• Carbon dioxide limits could be used in Chile. If they are at reasonable levels they do not need to cost that much and could really help the sustainable energy sources to become more interesting for investors.
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Cordes, Kevin Brian. "Leaching and bioavailability of selected elements from coal-fired power station waste." Thesis, University of Derby, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364831.
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Culley, Marci R. Hughey Joseph. "Power and "official" vehicles for public participation in a local hazardous waste setting a community case study /." Diss., UMK access, 2004.
Знайти повний текст джерелаАнотація:
Thesis (Ph. D.)--Dept. of Psychology. University of Missouri--Kansas City, 2004."A dissertation in community psychology." Advisor: Joseph B. Hughey. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Frb. 23, 2006. Includes bibliographical references (leaves 355-370). Online version of the print edition.
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Murer, Martin Johannes [Verfasser]. "Numerical methods for efficient power generation from municipal solid waste / Martin Johannes Murer." München : Verlag Dr. Hut, 2014. http://d-nb.info/1051550327/34.
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Gewald, Daniela [Verfasser]. "Waste heat recovery of stationary internal combustion engines for power generation / Daniela Gewald." München : Verlag Dr. Hut, 2013. http://d-nb.info/1045987735/34.
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Cedervall, Hanna, and Erik Hilmertz. "Waste – an asset : Assessment of a take-back system for electric power tools." Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156889.
Повний текст джерелаАнотація:
This master thesis has been conducted during the spring semester of 2013 at the Royal Institute of Technology in cooperation with Atlas Copco Industrial Technique. The work which has been performed was to analyze and evaluate the potential of a take-back system for discarded electric power tools. The goal has been to develop models for how such a system could be designed in order to achieve a decreased environmental impact, increased financial gains and a simplified end of life management for the customers in comparison with the current system. The work partly consisted of mapping the end of life handling activities of an electric nutrunner from the Atlas Copco product range, as well as find possible areas of improvement. Materials and components were evaluated in order to single out components with high material value, high internal purchasing price, lacking or inadequate handling or high environmental impact related to mining and extraction of the raw material. This evaluation served as a basis to single out components with high improvement potential from the perspective of recycling and reuse. Three concepts were developed based on the investigations, where single components or entire tools were returned to Atlas Copco. In the first concept, customers send the rotors to Atlas Copco, which reintroduces the rotors in the manufacturing line. The remaining two concepts involve entire tools to be sent to a common service workshop, where the electric motor and transducer is taken care of in varying extent by reintroduction to new production and reuse as spare parts after quality control. All three concepts leads to somewhat longer transportations than the standard way of handling the tools today, but was through a life cycle assessment evaluated to be able to render environmental benefits from 18 and 8 percent collected tools based on the European market. The system was calculated to finance its own transports, manual disassembly operations and economic incentive towards the customer to motivate them to return tools. To maximize the system potential, Atlas Copco should adopt design for disassembly in a more modularized way.Detta examensarbete har skrivits under vårterminen 2013 på Kungliga Tekniska högskolan i samarbete med Atlas Copco Industrial Technique AB. Arbetet som utförts har bestått av att analysera och utvärdera potentialen i ett återtagningssystem för kasserade elektriska monteringsverktyg. Målet har varit att komma fram till modellförslag för hur ett sådant system skulle kunna utformas för att uppnå en minskad miljöpåverkan, ökad ekonomisk vinning samt förenklad sluthantering för Atlas Copcos kunder i jämförelse med dagens hanteringssystem. Arbetet bestod dels av att kartlägga hur en elektrisk mutterdragare ur Atlas Copcos sortiment tas om hand idag samt att identifiera möjliga områden för förbättring. Material och komponenter utvärderades för att finna komponenter med högt materiellt värde, hög produktionskostnad, dålig eller bristfällig hantering alternativt stor miljöpåverkan i utvinningsfas. Denna miljömässiga och ekonomiska utvärdering låg därefter till grund för att hitta komponenter med förbättringspotential ur ett återvinnings- och återbruksperspektiv. Utifrån undersökningarna togs tre modellförslag fram där hela verktyg eller enstaka komponenter återlämnas till Atlas Copco. I det första konceptet skickar kunden in rotorer till Atlas Copco som återför rotorn in i nyproduktion. I övriga två koncept skickas hela verktyg in till en gemensam serviceverkstad, där den elektriska motorn samt momentgivaren tas till vara på i olika utsträckning genom återinförande i nyproduktion samt återbruk som reservdelar efter kvalitetskontroll. Samtliga tre koncept medför något längre transporter än standardsättet att hantera verktyg idag, men bedömdes med hjälp av en livscykelanalys kunna ge miljömässiga fördelar från och med 18 respektive 8 procent insamlade verktyg baserat på den Europeiska marknaden. Systemet beräknades kunna resultera i intäkter som täcker finansiering av transport, manuell isärplockning samt en mindre pant eller rabatt på nästa köp för att motivera kunder att återlämna verktygen. För att maximera potentialen i systemet bör Atlas Copcos verktyg i framtiden konstrueras med återbruk i åtanke på ett mer modulbaserat sätt än vad som görs idag.
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Albatati, Faisal Ali S. "Investigation of environmentally friendly power generation systems for low-grade waste heat recovery." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28990/.
Повний текст джерелаАнотація:
From the point of view of energy importance and the environmental impacts associated with conventional energy production methods, and for the purpose of low-grade waste heat recovery, this thesis demonstrates an investigative approach to develop and test a novel, environmentally friendly small-scale Rankine based power generation prototype system. To fulfil the aim, a range of systems of different technologies, and employing different working fluids were investigated to identify the most efficient, cost-effective system for the application. These systems are the absorption power generation system, and the flood expansion power generation system employing CO2/Lubricant mixture as the working fluid, the CO2 SRC power system, and finally the ORC system employing newly developed HFOs and HCFOR1233zd(E) refrigerants. The CO2/lubricant working fluid mixture was experimentally investigated and thermodynamically modelled. The performance of the investigated systems was theoretically evaluated by computer simulations. The results revealed that the ORC outperformed all other investigated systems, achieving thermal efficiency and net thermal power output of 14.36% and 4.81 kW respectively with R1233zd(E). In addition, the evaluation confirmed the capability of the new refrigerants to replace conventional refrigerants. A small-scale R1233zd(E) ORC prototype system utilising a specially developed scroll expander was constructed and tested. In the First Experiment, an automotive motor was utilised as the electric generator. The system’s optimum performance was 7.87% thermal efficiency, 1.39 kW expander power output, and 180 W electric power output. The main source of performance limitation was identified as the lower capability of the steam humidifier heat source, in addition to the speed mismatch between the expander and the motor, the poor performance of the circulation pump, and the piping configuration in relation to the positions of heat exchangers. Piping and the position of heat exchangers were altered, the motor was replaced by an alternator and the second experiment commenced in which the best overall experimental performance of 7.6% thermal efficiency, 1 kW expander power output, 246 W electric power output, was achieved. Very poor pump efficiency and a large power loss through the power transmission mechanism to the alternator were observed. Upon completion of the experiments, the theoretically predicted performance was validated, and the experimentally obtained results were compared to those of similar ORCs from literature. The comparison revealed that for the utilised expander type, a mass flow rate of 0.074 kg/s, and a pressure ratio of 4.5, achieves the best expander efficiency of 75%. From an economic point of view, the R1233zd(E) ORC was shown to be a very attractive and safe investment even for scaled- up systems. The thesis concluded that the ORC technology remains the most efficient, flexible technology for low-grade heat recovery, and the evaluation of R1233zd(E) for the first time expressed the attractive potentials of the refrigerant in ORC applications. Finally, justified recommendations were made to replace the heat source and refrigerant pump and to test other types of expander in order to improve the performance of the R1233zd(E) ORC prototype system.
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Liang, Li. "Recycling of concrete waste with wood waste through heating compaction." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-275674.
Повний текст джерелаАнотація:
Concrete, as primary building material, is widely used in most construction project. For this reason, large amounts of concrete waste were generated from construction and demolition. One way to reuse concrete waste is to use it as backfill material for landfilling and road bases. While the demand for backfill material is decreasing as the basic infrastructure construction gradually completes. Another way to reuse concrete waste is to grind it and use it as aggregate in casting new concrete. However, the reuse as aggregate for casting concrete requires large amount of cement. It is unsustainable because the production of cement causes significant amounts of carbon dioxide emission. How to deal with the concrete waste in a sustainable way is presently an urgent issue. Powder compaction is a new approach to completely recycle concrete waste in an environmentally friendly way. This new method was studied in the Sakai lab of the Institute of Industrial Science, The University of Tokyo. The process consists of crushing and milling concrete waste into a fine powder, filling the powder into moulds and compacting it under high pressure. By this process concrete waste powder can be turned into a solid concrete with mechanical properties so that it has potentials to be used again as a building material. Data from previous studies show that the compacted concrete waste can reach strength for construction but the required compaction pressure is quite high. Wood flour can be added in compaction for improving tensile strength and reducing compaction pressure. Lignin is a wood substance that melts under high temperature, fills gaps and improves bonding between particles. Cellulose from the wood substance functions as fibres which improves tensile strength. Wood waste from production of timber building materials, furniture and other wooden products also forms a larger quantities. Recycling of concrete waste with wooden waste through heating compaction is a potentially sustainable method. This Master thesis presents research on the effect from different production conditions on the bending strength of recycled concrete waste with wood waste through heating compaction. The condition factors studied were compaction duration, compaction pressure, concrete proportion, mixture percentage, temperature and particle size of wood flour. To enhance the water resistance of this recycled product, different water resistance treatments were discussed theoretically. The independence of production condition factors was analysed using a statistic method. Results indicated that within a certain range, an increase in compaction duration, compaction pressure, the percentage of wood waste and temperature improves the bending strength of the recycled products. Using smaller particle size of wood flour cannot improve compaction but contribute to give higher bending strength. The mechanical properties of these recycled products suggest application as non-bearing building material, such as decoration tiles and bricks for partition walls. The application as a structural material is expected in the future as improvement treatments are discovered.
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Ramakrishnan, Karthik. "Title Optimization and Process modelling of Municipal Solid Waste using Plasma Gasification for Power Generation in Trichy, India." Thesis, KTH, Materialvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157545.
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Wasantakorn, Aran. "Efficient power generation by integrating a MSW incinerator with a combined cycle gas turbine plant." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369938.
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Taylor, Alexander. "Strategies for co-operated wood chip fired and municipal waste fired combined heat and power plants." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96751.
Повний текст джерелаАнотація:
The Brista 1 plant is a wood chip-fired combined heat and power (CHP) plant located near Märsta, northwest of Stockholm, Sweden. The primary purpose of the plant is to supply heat to the northwest district heating grid. In order to meet increasing demand for district heating, Fortum Heat is constructing a second CHP plant next to Brista 1. The Brista 2 plant will use a mixture of municipal and industrial waste as fuel. Due to changes in the European Green Certificate program, the fuel subsidies for wood chips will be significantly reduced. This will cause the Brista 1 plant to incur significantly increased operating costs. The Brista 2 plant, however, will not be affected by these changes and will therefore be much cheaper to run than Brista 1. However, due to the large demand for district heating it will be necessary to run both plants in parallel at certain times in order to meet the heating demand and/or maximize revenue during periods of high electricity demand. A computer program has been constructed using MATLAB which simulates the Brista 1 and 2 plants and their combined operation in both backpressure and direct condensing mode. The results show that the optimum allocation of heat production does not seem to be affected by electricity price assuming both plants are operated in backpressure mode. The reason for this would seem to be that the production costs (fuel, emissions, O&M) are unaffected by the electricity price. Therefore, the allocation which maximizes electrical power production, and thus revenue from electricity sales, will always be favored. In certain cases, it is more profitable to run the Brista 1 plant in direct condensing mode. The reason for this would seem to be that the thermal efficiency is somewhat higher, and that at low electricity prices the revenues from electricity sales do not offset the cost of the reduced heat production.
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Kithsiri, Udalamattha Gamage. "Performance Improvement of a Diesel Engine Power Plant with Optimal Utilization of Waste Heat." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-21972.
Повний текст джерелаАнотація:
Due to temperature and humidity deviations from the standard ISO conditions in real operational conditions in the tropical countries the performance of diesel engines used for power generation drops significantly. One of the reasons for dropping the engine performance is due to engine de-rating, hence increasing the specific fuel consumption. The present study was undertaken to develop a model for predicting whether the prevailing site conditions cause de-rating at a specific power plant in Sri Lanka. The model was developed with the aid of recorded information in previous studies and was validated with site conditions revenant to a selected location in Sri Lanka. In the study a set of equations was developed corresponding to different temperatures to predict engine de-rating as a function of relative air humidity. To achieve the required standard conditions in view of avoiding any de-rating of the engines, the charge air temperature needed to be reduced. For this purpose an absorption chiller system was proposed and designed to be operated with the waste heat recovery from the power plant. It proved that implementation of such a system is technically and economically feasible with a simple payback period of three and a half years on the capital invested. This derived model was applied to actual operational data of the selected power plant and finally it was found a derated power of 417 kW could be fully recovered by conditioning the temperature and humidity of charge air to obtain the ISO conditions, giving a benefit equivalent fuel savings of 2233 kg/day.
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THORSSON, BJÖRN J., and HADY R. SOLIMAN. "Supercritical Carbon Dioxide Brayton Cycle for Power Generation : Utilizing Waste Heat in EU Industries." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282919.
Повний текст джерелаАнотація:
The industrial sector accounts for approximately 30% of the global total energy consumption and up to 50% of it is lost as waste heat. Recovering that waste heat from industries and utilizing it as an energy source is a sustainable way of generating electricity. Supercritical CO2 (sCO2) cycles can be integrated with various heat sources including waste heat. Current literature primarily focuses on the cycle’s performance without investigating the economics of the system. This is mainly due to the lack of reliable cost estimates for the cycle components. Recently developed cost scaling models have enabled performing more accurate techno-economic studies on these systems. This enables a shift in focus from plant efficiency to economics as a driver for commercialization of sCO2 technology. This work aims to develop a techno-economic model for these waste-heat-to-power systems. Based on the literature, waste heat from different industries is calculated, showing that the four industries with the greatest potential for waste heat recovery are cement, iron and steel, aluminum and gas compressor stations. Six different sCO2 cycle configurations were developed and simulated for these four industries. The techno-economic model optimizes for the highest Net Present Value (NPV) using an Artificial Bee Colony algorithm. The optimization variables are the pressure levels, split ratios, recuperators effectiveness, condenser temperature and the turbine inlet temperature limited by the heat source. The results show a vast potential for industries to cut down costs using this system. Out of the four industries modeled, a waste heat recovery system in an iron and steel factory yielded the highest NPV. Results show that the integration of sCO2 cycle in the cement industry could help reduce their waste heat by 60%, whilst simultaneously enabling them to cover up to 56% of their electricity demand. The payback period for the four industries varies between 6 to 9 years. Furthermore, simple recuperated sCO2 cycles with preheating are more economical than recompression cycles. Even though recompression cycles have higher thermal efficiency, they are limited by the temperature glide in the waste heat exchanger. This analysis could help investors and engineers take more informed decisions to increase the efficiency and economic return on investment for sCO2 cycles and heat recovery at industrial sites. To encourage adoption of supercritical CO2 cycles, a demo is needed along with more research for higher temperature applications with special attention to mechanical integrity.Industrisektorn står för cirka 30% av den globala totala energiförbrukningen och upp till 50% av den går förlorad som spillvärme. Återskapa att spillvärme från industrier och använda det som energikälla är ett hållbart sätt att producera el. Superkritiska CO2 (sCO2) cykler kan integreras med olika värmekällor inklusive spillvärme. Nuvarande litteratur fokuserar främst på cykelens prestanda utan att undersöka systemets ekonomi. Detta beror främst på bristen på tillförlitliga kostnadsberäkningar för cykelkomponenterna. Baserat på nyligen utvecklade kostnadsskalningsmodeller är det möjligt att utföra mer exakta teknikekonomiska studier på dessa system. Detta möjliggör en förskjutning i fokus från cykeleffektivitet till ekonomi som drivkraft för kommersialisering av sCO2 teknologi. Detta arbete syftar till att utveckla en teknisk ekonomisk modell för dessa avfall-värme-till-kraftsystem. Baserat på litteraturen beräknas spillvärme från olika industrier, vilket visar att de fyra industrierna med störst potential för återvinning av spillvärme är cement, järn och stål, aluminium och gaskompressorstationer. Sex olika sCO2 konfigurationer utvecklades och simulerades för dessa fyra industrier. Den teknisk-ekonomiska modellen optimerar för det högsta Net Present Value (NPV) med hjälp av en artificiell bi-kolonialgoritm. Optimeringsvariablerna är pressure levels, delade förhållanden, recuperatorseffektivitet, kondensortemperatur och turbininloppstemperaturen begränsad av värmekällan. Resultaten visar en stor potential för industrier att sänka kostnaderna med detta system. Av de fyra modellerna industrin gav ett återvinningssystem i en järn och stålfabrik den högsta NPV. Resultaten visar att integrationen av sCO2 cykeln i cementindustrin kan bidra till att minska deras spillvärme med 60%, samtidigt som de gör det möjligt för dem att täcka upp till 56% av deras elbehov. Återbetalningsperioden för de fyra branscherna varierar mellan 6 till 9 år. Dessutom är simple recuperated sCO2 cykler med förvärmning mer ekonomiska än recompressioncykler. Trots att recompressioncykler har högre termisk effektivitet, begränsas de av temperaturglidningen i spillvärmeväxlaren. Denna analys kan hjälpa investerare och ingenjörer att fatta mer informerade beslut för att öka effektiviteten och ekonomiska avkastningen på investeringar för sCO2 cykler och värmeåtervinning på industriområden. För att uppmuntra antagandet av superkritiska CO2 cykler krävs en demo tillsammans med mer forskning för högre temperaturapplikationer med särskild uppmärksamhet på mekanisk integritet.
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Staniforth, J. "The use of biogas to power a small tubular solid oxide fuel cell." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311728.
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Alipour, Yousef. "High temperature corrosion in a biomass-fired power boiler : Reducing furnace wall corrosion in a waste wood-fired power plant with advanced steam data." Licentiate thesis, KTH, Yt- och korrosionsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121155.
Повний текст джерелаАнотація:
The use of waste (or recycled) wood as a fuel in heat and power stations is becoming more widespread in Sweden (and Europe), because it is CO2 neutral with a lower cost than forest fuel. However, it is a heterogeneous fuel with a high amount of chlorine, alkali and heavy metals which causes more corrosion than fossil fuels or forest fuel. A part of the boiler which is subjected to a high corrosion risk is the furnace wall (or waterwall) which is formed of tubes welded together. Waterwalls are made of ferritic low-alloyed steels, due to their low price, low stress corrosion cracking risk, high heat transfer properties and low thermal expansion. However, ferritic low alloy steels corrode quickly when burning waste wood in a low NOx environment (i.e. an environment with low oxygen levels to limit the formation of NOx). Apart from pure oxidation two important forms of corrosion mechanisms are thought to occur in waste environments: chlorine corrosion and alkali corrosion. Although there is a great interest from plant owners to reduce the costs associated with furnace wall corrosion very little has been reported on wall corrosion in biomass boilers. Also corrosion mechanisms on furnace walls are usually investigated in laboratories, where interpretation of the results is easier. In power plants the interpretation is more complicated. Difficulties in the study of corrosion mechanisms are caused by several factors such as deposit composition, flue gas flow, boiler design, combustion characteristics and flue gas composition. Therefore, the corrosion varies from plant to plant and the laboratory experiments should be complemented with field tests. The present project may thus contribute to fill the power plant corrosion research gap. In this work, different kinds of samples (wall deposits, test panel tubes and corrosion probes) from Vattenfall’s Heat and Power plant in Nyköping were analysed. Coated and uncoated samples with different alloys and different times of exposure were studied by scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and light optical microscopy (LOM). The corrosive environment was also simulated by Thermo-Calc software. The results showed that a nickel alloy coating can dramatically reduce the corrosion rate. The corrosion rate of the low alloy steel tubes, steel 16Mo3, was linear and the oxide scale non-protective, but the corrosion rate of the nickel-based alloy was probably parabolic and the oxide much more protective. The nickel alloy and stainless steels showed good corrosion protection behavior in the boiler. This indicates that stainless steels could be a good (and less expensive) alternative to nickel-based alloys for protecting furnace walls. The nickel alloy coated tubes (and probe samples) were attacked by a potassium-lead combination leading to the formation of non-protective potassium lead chromate. The low alloy steel tubes corroded by chloride attack. Stainless steels were attacked by a combination of chlorides and potassium-lead. The Thermo-Calc modelling showed chlorine gas exists at extremely low levels (less than 0.1 ppm) at the tube surface; instead the hydrated form is thermodynamically favoured, i.e. gaseous hydrogen chloride. Consequently chlorine can attack low alloy steels by gaseous hydrogen chloride rather than chlorine gas as previously proposed. This is a smaller molecule than chlorine which could easily diffuse through a defect oxide of the type formed on the steel.QC 20130423
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Slabbert, Michael Charles. "Utilising waste products from Kwinana industries to manufacture low specification geopolymer concrete." Thesis, Curtin University, 2008. http://hdl.handle.net/20.500.11937/606.
Повний текст джерелаАнотація:
One technology that makes concrete without cement and does not have the associated carbon footprint is geopolymer concrete. This technology utilizes waste fly ash from power stations and mixes it with activating chemicals to form a binder with similar or better properties than cement. Not only does this technology directly reduce carbon emissions by replacing cement it also utilizes the waste bi-product from power stations and prevents it from going to landfill. Concrete is composed of coarse aggregates, sand and cementitious paste. It seemed possible to make geopolymer concrete from 100% waste. The aggregates would come from recycled concrete and hard brittle bottom ash from power stations, the sand would come from foundries and the fly ash binder would also come from the same power station as the bottom ash. All of these materials are waste and would all be dumped in landfill. Where would one find all these waste materials in one place? The industrial suburb of Kwinana outside Perth is home to a large number of industries producing all these wastes. To find products that have a specification that these materials would suit was a material with a relatively low specification, one such specification is the concrete masonry units’ specification. For this to be adopted the mix design would then have to be altered to a drier type mix without any slump. As recycling facilities do not make a range of products it was decided to crush the aggregates in the laboratory specifically for this research and to blend all the waste materials. Numerous combinations were blended, analysed and assessed to establish which blends would best suit the aims and scope of this research. Eventually three blends were selected that encompassed all the waste products.To find the right mix design proved challenging as these masonry products generally require a mix to have zero slump. It was decided to test across all the known and analysed water to geopolymer solids ratios for each of the mixes and establish the best mix based on compressive strength, workability and slump A known mix design based on research into low calcium Class F geopolymer concrete, developed at Curtin University using natural aggregates, was applied to these selected recycled waste mix designs. The benefit was to be able to compare the results of this research to a known result. Flash setting, an unknown phenomenon in geopolymer concrete, did occur in the low water mixes, but in spite of this, geopolymer concrete was successfully manufactured. The compressive strengths were substantially lower than those of the design mix and more research is required in this regard, however an indirect relationship was observed between the amount of bottom ash and the compressive strength. The high degree of LOI (loss of ignition) in both ashes, porosity of recycled aggregates, angularity, degree of fineness of the fines and flash setting are all possible factors influencing the properties of the geopolymer concrete. More research is recommended in a number of these areas to be able to understand and develop this technology further in order to make this a practical and robust technology in the quest to find solutions to our warming planet and our changing climate.
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Talbi, Mosbah Mohamed. "A theoretical study and simulation of the diesel-absorption unit." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313506.
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Islam, Fahmida. "Evaluation of low power sonication on anaerobic digestion of municipal waste sludge and energy recovery." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53774.
Повний текст джерелаАнотація:
Ultrasound is one of the emerging pre-treatment technologies to enhance anaerobic digestion process, however high energy input requirement is a concern. This study investigated a low power sonication pre-treatment on anaerobic digestion under thermophilic (55⁰C) and mesophilic (35⁰C) digester temperatures. Low ultrasonic densities (0.08 to 0.25 W/mL) and specific energies (1,211 to 15,094 kJ/kg total solids (TS)) were applied to thickened waste activated sludge (TWAS) from Kelowna’s wastewater treatment plant (WWTP) to determine optimal sludge disintegration (solubilisation) conditions. At 0.25 W/mL and 11,343 kJ/kg TS, maximum solubilisation of organic matters and highest particle size reduction were observed. Following solubilisation, anaerobic digesters utilizing a mixture of primary sludge and pre-treated TWAS indicated that at shorter digestion solid retention times (SRT), the sonication effect on biogas production under mesophilic conditions was more pronounced. In an organic loading rate range of 1.8~6.8 g volatile solids (VS)/L of digester/d), corresponding to SRTs of 20-5 days, thermophilic digesters exhibited process instability with an increase in organic loading as well as ultrasound intensity applied due to reduced microbial diversity of methane formers at elevated temperatures. On the other hand, thermophilic digesters were more successful in fecal coliform destruction than mesophilic digesters due to elevated temperatures. Sonication enhanced dewaterability for mesophilic digesters (sonicated at 4163 and 8153 kJ/Kg TS) at higher SRTs and all thermophilic pre-treated digesters at 20 day SRT. However, sonication did not reduce odour causing volatile sulfur compounds in headspace of digesters. In an energy feasibility study, at 20 day and 10 day SRTs for all the digestion systems, the energy balance came out positive due to higher volume of biogas (methane) generated. Overall, among all digestion systems, the mesophilic digester (sonicated at 4063 kJ/kg TS) showed the highest stability at the shortest SRT of 5 days with significant (80%) increase in gas production and organic removal efficiency over control (un-pre-treated) digester. However, the results also indicated that at longer (safer) SRTs 10 and 20 days, low power sonication pre-treatment (2042 to 8153 kJ/kg TS) did not represent substantial benefits in terms of organic removals, biogas production, fecal coliform destruction or enhancement in dewaterability.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Eichelberger, Laura Palen. "MANUFACTURING INSECURITY: POWER, WATER, WASTE, AND THE SILENCES OF SUSTAINABILITY AND SUFFERING IN NORTHWEST ALASKA." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/204332.
Повний текст джерелаАнотація:
With its oil wealth and an environment of abundant rivers, lakes, and the largest coastline in the United States, Alaska is one of the last places one would expect to find water insecurity. Yet approximately one third of households in remote Alaska Native villages lack in-home piped water and suffer the health consequences of poor sanitation and inadequate treated water. This problem has become particularly acute in the wake of surging energy prices and a concomitant shift in policies that increasingly require demonstrated economic sustainability before funding will be allocated for village water and sanitation projects. In response to increasing costs of living and the failure of development projects to foster the conditions under which they would be able to provide for their needs, many Iñupiat assert the importance of traditional values, practices and values that from their view constitute a path out of insecurity and into self-sufficiency. These Iñupiat point to modern technology as the source of what they call the spoiling of their communities. In this dissertation, I explore the disjuncture between how the state and the Iñupiat signify historical and contemporary issues and solutions around water, energy, and development. I suggest that the unintended consequences of decades of interventions to improve Iñupiaq health and well-being have been manufactured insecurity that is exacerbated by weakened social networks of reciprocity (the Iñupiaq traditional value of sharing), and rendered invisible by sustainability policies. I argue that these multifaceted processes of domination and suffering are all part of what many Iñupiat describe spoiling. In other words, when the Iñupiat talk about being spoiled by technology, they are talking about the historical domination by the state over their social reproduction in ways that produce and exacerbate the insecurities characterizing daily life in these remote villages.
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Ajimotokan, Habeeb A. "A study of trilateral flash cycles for low-grade waste heat recovery-to-power generation." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9202.
Повний текст джерелаАнотація:
There has been renewed significance for innovative energy conversion
technologies, particularly the heat recovery-to-power technologies for
sustainable power generation from renewable energies and waste heat. This is
due to the increasing concern over high demand for electricity, energy shortage,
global warming and thermal pollution. Among the innovative heat recovery-to-
power technologies, the proposed trilateral flash cycle (TFC) is a promising
option, which presents a great potential for development. Unlike the Rankine
cycles, the TFC starts the working fluid expansion from the saturated liquid
condition rather than the saturated, superheated or supercritical vapour phase,
bypassing the isothermal boiling phase. The challenges associated with the
need to establish system design basis and facilitate system configuration
design-supporting analysis from proof-of-concept towards a market-ready TFC
technology are significant. Thus, there is a great need for research to improve
the understanding of its operation, behaviour and performance. The objective of
this study is to develop and establish simulation tools of the TFCs for improving
the understanding of their operation, physics of performance metrics and to
evaluate novel system configurations for low-grade heat recovery-to-power
generation. This study examined modelling and process simulation of the TFC
engines in order to evaluate their performance metrics, predictions for guiding
system design and parameters estimations. A detailed thermodynamic analysis,
performance optimization and parametric analysis of the cycles were
conducted, and their optimized performance metrics compared. These were
aimed at evaluating the effects of the key parameters on system performances
and to improve the understanding of the performance behaviour. Four distinct
system configurations of the TFC, comprising the simple TFC, TFC with IHE,
reheat TFC and TFC with feed fluid-heating (or regenerative TFC) were
examined. Steady-state steady-flow models of the TFC power plants,
corresponding to their thermodynamic processes were thermodynamically
modelled and implemented using engineering equation solver (ESS). These
models were used to determine the optimum synthesis/ design parameters of the cycles and to evaluate their performance metrics, at the subcritical operating
conditions and design criteria. Thus, they can be valuable tools in the
preliminary prototype system design of the power plants. The results depict that
the thermal efficiencies of the simple TFC, TFC with IHE, reheat TFC and
regenerative TFC employing n-pentane are 11.85 - 21.97%, 12.32 - 23.91%,
11.86 - 22.07% and 12.01 - 22.9% respectively over the cycle high temperature
limit of 393 - 473 K. These suggest that the integration of an IHE, fluid-feed
heating and reheating in optimized design of the TFC engine enhanced the heat
exchange efficiencies and system performances. The effects of varying the
expander inlet pressure at the cycle high temperature and expander isentropic
efficiency on performance metrics of the cycles were significant. They have
assisted in selecting the optimum-operating limits for the maximum performance
metrics. The thermal efficiencies of all the cycles increased as the inlet
pressures increased from 2 - 3 MPa and increased as the expander isentropic
efficiencies increased from 50 - 100%, while their exergy efficiencies increased.
This is due to increased net work outputs that suggest optimal value of pressure
ratios between the expander inlets and their outlets. A comprehensive
evaluation depicted that the TFC with IHE attained the best performance
metrics among the cycles. This is followed by the regenerative TFC whereas
the simple TFC and reheat TFC have the lowest at the same subcritical
operating conditions. The results presented show that the performance metrics
of the cycles depend on the system configuration, and the operating conditions
of the cycles, heat source and heat sink. The results also illustrate how system
configuration design and sizing might be altered for improved performance and
experimental measurements for preliminary prototype development.
33
Liyanage, Charith. "Development of a small scale IGCC power plant using solid waste at Hambantota, Sri Lanka." Thesis, Högskolan i Gävle, Akademin för teknik och miljö, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-16334.
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Fransson, Erik, and Daniel Olsson. "Thermoelectric Generators : A comparison of electrical power outputs depending on temperature." Thesis, Högskolan Dalarna, Institutionen för information och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:du-38031.
Повний текст джерелаАнотація:
Today many processes generate a lot of waste heat, for example industries or cars. One way to make this thermal energy useful is to transform it into electrical energy with a thermoelectric generator (TEG) or thermoelectric cooler (TEC). This technology is not used in any large scale today, but a lot of research is being done on the subject. The technology is based on the Seebeck effect and uses a temperature difference between two sides of an element to generate an electrical current. The reason that the research has gained more attention in recent years is because of the increasing electricity prices and the diminishing natural resources. Other benefits are that they run quietly and do not demand much maintenance.Another area where this technology could be useful is in off-grid cabins where it is easy to generate a lot of thermal energy by burning wood, but electrical energy is in high demand.In this thesis two different types of TEGs and one type of TEC are tested to investigate how much power they generate at different temperature differences, how well they meet the specified values in their respective data sheet and what their power per euro value is. For this, an experimental setup was made with:- An induction plate to increase the temperature on the hot side.- A CPU-fan, to reduce the temperature on the cold side.- Two temperature sensors (one for measuring the hot temperature and one for the cold one).- An electric circuit featuring a voltmeter, an amperemeter and an adjustable resistor (rheostat).The results show that, for this experiment the highest received power (6,38 W) comes from the medium-priced element but the highest power per euro comes from the lowest priced element (1,16 W/€). A quality problem for the lowest priced element was that parts of the solder melted when the temperature exceeded 225 °C. Another problem was that the induction plate was unable to provide enough heat for the most expensive of the elements to reach the temperature for which the retailer supplies their measured data.
35
Kishore, Ravi Anant. "Low-grade Thermal Energy Harvesting and Waste Heat Recovery." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/103650.
Повний текст джерелаАнотація:
Low-grade heat, either in the form of waste heat or natural heat, represents an extremely promising source of renewable energy. A cost-effective method for recovering the low-grade heat will have a transformative impact on the overall energy scenario. Efficiency of heat engines deteriorates with decrease in hot-side temperature, making low-grade heat recovery complex and economically unviable using the current state-of-the-art technologies, such as Organic Rankine cycle, Kalina cycle and Stirling engine. In this thesis, a fundamental breakthrough is achieved in low-grade thermal energy harvesting using thermomagnetic and thermoelectric effects. This thesis systematically investigates two different mechanisms: thermomagnetic effect and thermoelectric effect to generate electricity from the low-grade heat sources available near ambient temperature to 200�[BULLET]C. Using thermomagnetic effect, we demonstrate a novel ultra-low thermal gradient energy recovery mechanism, termed as PoWER (Power from Waste Energy Recovery), with ambient acting as the heat sink. PoWER devices do not require an external heat sink, bulky fins or thermal fluid circulation and generate electricity on the order of 100s μW/cm3 from heat sources at temperatures as low as 24�[BULLET]C (i.e. just 2�[BULLET]C above the ambient) to 50�[BULLET]C. For the high temperature range of 50-200�[BULLET]C, we developed the unique low fill fraction thermoelectric generators that exhibit a much better performance than the commercial modules when operated under realistic conditions such as constant heat flux boundary condition and high thermally resistive environment. These advancements in thermal energy harvesting and waste heat recovery technology will have a transformative impact on renewable energy generation and in reducing global warming.PHD
36
Woo, Pak-wai Jimmy, and 胡百偉. "The management of flue gas desulphurization waste in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31253313.
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Yesilbas, Gulsah. "Stabilization Of Expansive Soils By Using Aggregate Waste, Rock Powder And Lime." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604950/index.pdf.
Повний текст джерелаАнотація:
Expansive soils are a worldwide problem that poses several challenges for civil engineers. Such soils swell when given an access to water and shrink when they dry out. The most common and economical method for stabilizing these soils is using admixtures that prevent volume changes. In this study the effect of using rock powder and aggregate waste with lime in reducing the swelling potential is examined. The expansive soil used in this study is prepared in the laboratory by mixturing kaolinite and bentonite. Lime was added to the soil at 0 to 9 percent by weight. Aggregate waste and rock powder were added to the soil at 0 to 25 percent by weight. Grain size distribution, Atterberg limits and swell percent and rate of swell of the mixtures were determined. Specimens were cured for 7 and 28 days. This method of treatment caused a reduction in the swelling potential and the reduction was increased with increasing percent stabilizers.
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Li, Liang. "Experimental and theoretical investigation of CO2 trans-critical power cycles and R245fa organic Rankine cycles for low-grade heat to power energy conversion." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/14766.
Повний текст джерелаАнотація:
Globally, there are vast amounts of low-grade heat sources from industrial waste and renewables that can be converted into electricity through advanced thermodynamic power cycles and appropriate working fluids. In this thesis, experimental research was conducted to investigate the performance of a small-scale Organic Rankine Cycle (ORC) system under different operating conditions. The experimental setup consisted of typical ORC system components, such as a turboexpander with a high speed generator, a scroll expander, a finned-tube condenser, an ORC pump, a plate evaporator and a shell and tube evaporator. R245fa was selected as the working fluid, on account of its appropriate thermophysical properties for the ORC system and its low ozone depletion potential (ODP). The test rig was fully instrumented and extensive experiments carried out to examine the influences of several important parameters, including heat source temperature, ORC pump speed, heat sink flow velocity, different evaporators and with or without a recuperator on overall R245fa ORC performances. In addition, in terms of the working fluid’s environmental impact, temperature match of the cycle heat processes and system compactness, CO2 transcritical power cycles (T-CO2) were deemed more applicable for converting low-grade heat to power. However, the system thermal efficiency of T-CO2 requires further improvement. Subsequently, a test rig of a small-scale power generation system with T-CO2 power cycles was developed with essential components connected; these included a plate CO2 supercritical heater, a CO2 transcritical turbine, a plate recuperator, an air-cooled finned-tube CO2 condenser and a CO2 liquid pump. Various preliminary test results from the system measurements are demonstrated in this thesis. At the end, a theoretical study was conducted to investigate and compare the performance of T-CO2 and R245fa ORCs using low-grade thermal energy to produce useful shaft or electrical power. The thermodynamic models of both cycles were developed and applied to calculate and compare the cycle thermal and exergy efficiencies at different operating conditions and control strategies. In this thesis, the main results showed that the thermal efficiency of the tested ORC system could be improved with an increased heat source temperature in the system with or without recuperator. When the heat source temperature increased from 145 oC to 155 oC for the system without recuperator, the percentage increase rates of turbine power output and system thermal efficiency were 13.6% and 14% respectively while when the temperature increased from 154 oC to 166 oC for the system with recuperator, the percentage increase rates were 31.2% and 61.97% respectively. In addition, the ORC with recuperator required a relative higher heat source temperature, which is comparable to a system without recuperator. On the other hand, at constant heat source temperatures, the working fluid pump speed could be optimised to maximise system thermal efficiency for ORC both with and without recuperator. The pressure ratio is a key factor impacting the efficiencies and power generation of the turbine and scroll expander. Maximum electrical power outputs of 1556.24W and 750W of the scroll expander and turbine were observed at pressure ratio points of 3.3 and 2.57 respectively. For the T-CO2 system, the main results showing that the CO2 mass flow rate could be directly controlled by varying the CO2 liquid pump speeds. The CO2 pressures at the turbine inlet and outlet and turbine power generation all increased with higher CO2 mass flow rates. When CO2 mass flow rate increased from 0.2 kg/s to 0.26kg/s, the maximum percentage increase rates of measured turbine power generation was 116.9%. However, the heat source flow rate was found to have almost negligible impact on system performance. When the thermal oil flow rate increased from 0.364kg/s to 0.463kg/s, the maximum percentage increase rate of measured turbine power generation was only 14.8%. For the thermodynamic analysis, with the same operating conditions and heat transfer assumptions, the thermal and exergy efficiencies of R245fa ORCs are both slightly higher than those of T-CO2. However, the efficiencies of both cycles can be enhanced by installing a recuperator at under specific operating conditions. The experiment and simulation results can thus inform further design and operation optimisations of both the systems and their components.
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Sham, Devin Krishna. "Analysis of exhaust waste heat recovery techniques from stationary power generation engines using organic rankine cycles." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-123311.
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Mostafavi, Mahmood. "Theoretical and experimental investigation of using power plants (diesel engines) waste heat for adsorption refrigeration applications." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307832.
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Kohl, Ulrik. "The Copenhill Crisis. The Dark Side of Planning The Greenest Waste-fired Power Plant Ever Seen." Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-21591.
Повний текст джерелаАнотація:
This thesis is about the making of a power plant. It sheds light on how neoliberal ideas shape large public investments in sustainable energy infrastructure. It tells the story of how the City of Copenhagen decided to build what was claimed to be the greenest waste-fired power plant in the world: Copenhill. The plant was to have a ski slope at the rooftop and a chimney puffing smoke-rings. However, conflicting urban visions and rationalities led to a year-long crisis in the project’s planning phase. In the end, Copenhill was built over capacity, which today makes it difficult to match budget and costs. I combined information from internal municipal documents, interviews with decision makers and informal corridor talk to identify the driving forces behind the outcome of the crisis, and the contradictions and complexities of the case. I found that the crisis had roots in the way the public energy company ARC began to act like a private firm, with an entrepreneurial vision. ARC adopted an expansionist growth plan to build a large power plant with iconic architecture. The Copenhill project attracted local politicians wishing to brand Copenhagen as a green world city. However, the city’s Technical and Environmental Administration (TEA) was guided by a managerial vision with a strong sustainability focus. TEA’s analysis showed that there would not be enough garbage in the city to power the over-sized plant. Consequences for economy and environment were seen as potentially disastrous. Supported by city council and government, TEA tried to stop Copenhill. The clash between the two different urban visions led to the formation of two opposing coalitions with each their own rationality. The contradictions between growth rationality and green rationality caused the Copenhill Crisis. The direct intervention of the power élite in support of a growth solution short-circuited the norms of transparent public decision-making. Bowing to political pressure, TEA produced new documents saying that Copenhill would be great for economy and climate. Dark planning practices led to an outcome that was falsely presented as a compromise between green and growth strategies. It was in fact a growth solution, wrapped in green arguments that were not rational. The case study supports a key proposition in theory on the dark side of planning: that rationality is context-dependent and that the context of rationality is power. The case study adds insights to theory by showing the ways neoliberal thought merges with existing socio-economic conditions in space and time, specifically within a Nordic welfare-state context. It shows how public energy companies can face challenges, not only from neoliberal-driven privatization attempts, but also from ideas of iconicity and city marketing. The case study reaffirms the strength of a Flyvbjergian approach to understand the effects of hidden power mechanisms on planning of public energy infrastructure.
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Slabbert, Michael Charles. "Utilising waste products from Kwinana industries to manufacture low specification geopolymer concrete." Curtin University of Technology, Department of Civil Engineering, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=117996.
Повний текст джерелаАнотація:
One technology that makes concrete without cement and does not have the associated carbon footprint is geopolymer concrete. This technology utilizes waste fly ash from power stations and mixes it with activating chemicals to form a binder with similar or better properties than cement. Not only does this technology directly reduce carbon emissions by replacing cement it also utilizes the waste bi-product from power stations and prevents it from going to landfill. Concrete is composed of coarse aggregates, sand and cementitious paste. It seemed possible to make geopolymer concrete from 100% waste. The aggregates would come from recycled concrete and hard brittle bottom ash from power stations, the sand would come from foundries and the fly ash binder would also come from the same power station as the bottom ash. All of these materials are waste and would all be dumped in landfill. Where would one find all these waste materials in one place? The industrial suburb of Kwinana outside Perth is home to a large number of industries producing all these wastes. To find products that have a specification that these materials would suit was a material with a relatively low specification, one such specification is the concrete masonry units’ specification. For this to be adopted the mix design would then have to be altered to a drier type mix without any slump. As recycling facilities do not make a range of products it was decided to crush the aggregates in the laboratory specifically for this research and to blend all the waste materials. Numerous combinations were blended, analysed and assessed to establish which blends would best suit the aims and scope of this research. Eventually three blends were selected that encompassed all the waste products.To find the right mix design proved challenging as these masonry products generally require a mix to have zero slump. It was decided to test across all the known and analysed water to geopolymer solids ratios for each of the mixes and establish the best mix based on compressive strength, workability and slump A known mix design based on research into low calcium Class F geopolymer concrete, developed at Curtin University using natural aggregates, was applied to these selected recycled waste mix designs. The benefit was to be able to compare the results of this research to a known result. Flash setting, an unknown phenomenon in geopolymer concrete, did occur in the low water mixes, but in spite of this, geopolymer concrete was successfully manufactured. The compressive strengths were substantially lower than those of the design mix and more research is required in this regard, however an indirect relationship was observed between the amount of bottom ash and the compressive strength. The high degree of LOI (loss of ignition) in both ashes, porosity of recycled aggregates, angularity, degree of fineness of the fines and flash setting are all possible factors influencing the properties of the geopolymer concrete. More research is recommended in a number of these areas to be able to understand and develop this technology further in order to make this a practical and robust technology in the quest to find solutions to our warming planet and our changing climate.
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Loeser, Mathias. "Microscale biomass generation for continuous power supply to remote customers." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528152.
Повний текст джерелаАнотація:
Remotely located and sparsely populated areas often do not have access to an efficient grid connection for electricity supply. However, plenty of biomass is normally available in such areas. Instead of employing island solutions such as small diesel generators or large battery stacks for power provision, a flexibly operating microscale biomass power plant using locally available and renewable feedstock is not only an efficient way of providing those areas with competitive and reliable electricity, but also a step towards energy self sufficiency for a large share of areas worldwide, and towards mitigating the looming high costs of grid infrastructure upgrading and extension. A novel power plant design combining thermo chemical and biochemical biomass treatment was developed in this research. This system consists of a small scale gasifier and an anaerobic digester unit, both coupled to a gas storage system and a micro turbine as the generation unit. This design is suitable to continuously provide reliable electricity and accommodate fluctuating residential power demand, and it can be scaled to a level of around 100kWe, which is a fitting size for a group of residential customers, such as in a remote village. The project covers a review of available technology; the choice of suitable technology for such a plant and the design of the system; the set up of a detailed plant model in chemical engineering software; extensive simulation studies on the basis of load profiles to evaluate and optimise operation; and feedstock sourcing, efficiency and economic analyses. It will be shown that such a system is a feasible and economic solution for remote power supply, and that it can overcome many of the current obstacles of electrifying rural regions.
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ÓLAFSDÓTTIR, VERA SÓLVEIG. "Fällning av kisel från avloppsvatten vid Hellisheidarvirkjun - experimentell studie." Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170628.
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This report is about the experiments with mixing of the separated water and the vacuum pump seal water at Hellisheiði power plant. This is done to prevent silica scaling and clogging in pipes and reinjection wells as well as eliminating vacuum pump seal water from the plant. The experiments were done in four stages: the first stage comprised of tests with different flows of separated water at 70°C, the second stage was carried out by mixing the separated water at 70°C and the seal water with different amounts of the seal water, the third and the fourth stages were like the first and second but with the separated water at 120°C. The results show that this method is good if the mixture is around 50/50 separated water and seal water, to control the silica scaling in the separated water and to be able to reinject the seal water with the separated water. This does not eliminate the silica scaling in all of the separated water because the amount of separated water is much more than the amount of seal water that comes from the plant.
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Benato, A. "Power plants behaviour during transient operating conditions." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3423908.
Повний текст джерелаАнотація:
System dynamic modelling and simulation is becoming a powerful and essential design tool. For this reason, this Ph.D. Thesis is devoted to analyse the transient operation conditions’ effects using power plant dynamic models.
In the first part of this dissertation, the dynamic analysis is the core of a procedure developed to predict lifetime reduction on traditional power plant devices. In particular, the plant dynamic model, and its capability of evaluating the trends of
the main thermodynamic parameters, which describe the plant operation during transient conditions, is the base point to identify the most stressed plant devices.
Being fundamental the role played by combined cycle power plants in the liberalized electricity market scenario, a combined cycle power plant is selected as test case. The dynamic model of a single pressure combined cycle power unit is built and the proposed procedure is tested. The results show that the procedure can be considered as a valuable innovative tool to assist power plant designers and operators in order to improve the plant’s flexibility without excessively compromising the integrity of devices subjected to high thermo-mechanical stresses.
The second part of this work underlines the essential role played by the dynamic analysis during the design phase of innovative small-medium size waste heat recovery units on isolated grid. In particular, after a design optimization process, the dynamic behaviour of gas turbines coupled with waste heat recovery units
(ORC, SRC and ABC power units) is tested to verify the grid stability and, in the case of an ORC unit, the working fluid thermochemical stability.
In conclusion, in this dissertation, two different software tools are proposed. In both cases the core is the plant dynamic model. The first tool is able to predict the plant thermodynamic variables and compute the components lifetime reduction
caused by load changes while the second one performs a design and optimization of different waste heat recovery units for stand-alone offshore facilities. The entire plant is then dynamically analysed in order to verify the grid stability and, in the
case of ORC unit, the working fluid thermochemical stability.La simulazione dinamica sta diventando uno strumento sempre più potente ed essenziale sia nella fase di design che durante il processo di ottimizzazione e gestione dei sistemi di produzione dell’energia. Da questa nuova necessità è nata l’idea di studiare gli effetti indotti dalle variazioni di carico sui componenti che costituiscono gli impianti energetici. A tal fine si devono sviluppare dei modelli di impianto in grado di simulare il comportamento dinamico del sistema in esame. Nella prima parte di questo elaborato, l’analisi dinamica è il cuore di una procedura integrata sviluppata allo scopo di prevedere la riduzione di vita utile dei componenti maggiormente sollecitati degli impianti termoelettrici. In particolare, il modello dinamico dell’impianto, capace di simulare l’andamento delle principali grandezze termodinamiche e quindi il comportamento del sistema durante le variazioni di carico, è l’elemento centrale della procedura poichè consente di identificare i componenti maggiormente soggetti a fenomeni di stress derivante da fatica termo-meccanica. Dato che gli impianti a ciclo combinato sono la tecnologia attualmente più efficiente e maggiormente diffusa tra i produttori di energia operanti nel mercato liberalizzato della produzione, il caso studio selezionato per testare la procedura sviluppata è proprio un impianto a ciclo combinato a singolo livello di pressione. I risultati ottenuti dimostrano che la procedura è un metodo innovativo in grado di assistere sia i progettisti che gli operatori degli impianti poiché in grado di simulare il comportamento dinamico del sistema e fornire indicazioni fondamentali sugli effetti indotti dall'esercizio flessibile. Tuttavia, l’analisi dinamica riveste un ruolo centrale anche nel caso di progettazione di impianti medio-piccoli di recupero del calore di scarto. Questi impianti vengono generalmente impiegati per incrementare le prestazioni del sistema e ridurre contestualmente i consumi di combustibile e le emissioni inquinanti rilasciate in atmosfera. La seconda parte di questo elaborato si focalizza quindi sull'utilizzo e l’integrazione dell’analisi dinamica nel processo di design e gestione degli impianti di piccola potenza inseriti in reti stand-alone di piattaforme oil and gas. In particolare, dopo l’individuazione del case study (impianto costituito da tre turbine a gas in ciclo semplice) ed una fase di studio delle possibili configurazioni (tre turbine a gas alternativamente affiancate da differenti sistemi di recupero: ABC, SRC, ORC), differenti tipologie di impianto sono state progettate utilizzando una ottimizzazione multi-obiettivo. A partire da questi dati di design, sono stati costruiti i modelli dinamici delle diverse configurazioni di impianto al fine di verificare la stabilità della rete elettrica e, nel caso di un sistema di recupero basato sulla tecnologia ORC, del fluido termovettore impiegato nel ciclo sottoposto. In conclusione, nella presente tesi di dottorato vengono sviluppati due differenti computer tools. In entrambi i casi il cuore è costituito dal modello dinamico dell’impianto di produzione dell’energia. Nel primo tool software è implementata una procedura innovativa sviluppata con lo scopo di simulare il comportamento dell’impianto durante le variazioni di carico, predire il trend delle principali grandezze termodinamiche, individuare i componenti maggiormente sollecitati e calcolare la riduzione di vita utile indotta sui componenti. Il secondo tool, invece, realizza prima una progettazione ottimizzata di differenti tipologie di unità di recupero del calore di scarto per stand-alone offshore facilities. Quindi, il comportamento dinamico dell’impianto viene simulato in maniera tale da verificare la stabilità della rete elettrica e, nel caso di una unità ORC, la stabilità termochimica del fluido operativo di ciclo.
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Mesefir, Abdulmajeed. "Smart Home Project in Saudi Arabia: Reduce the Power Waste and Increase the Efficiency, Controllability and Sustainability." Digital Commons at Loyola Marymount University and Loyola Law School, 2016. https://digitalcommons.lmu.edu/etd/324.
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This paper proposes a deep study of the power consumption in Saudi Arabia homes. Today, clearly, Saudi homes waste a huge amount of power in each single home because of the high use rate for all home appliances. This is due, partially, to the extremely harsh desert climate in the country. There are many approaches to solve this problem; this paper will present one of the best solutions to solve the waste of the power in Saudi homes. The approach uses the latest technologies available today, including control tools and adopting the relying "Go Green" concept. The solution will be verified by verification and validation methods comparing the current home systems and the "Smart Hornes" system.
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Jain, Akshay. "Feasibility of using Waste Heat as a power source to operate Microbial Electrolysis Cells towards Resource Recovery." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97977.
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Wastewater treatment has developed as a mature technology over time. However, conventional wastewater treatment is a very energy-intensive process. Bioelectrochemical system (BES) is an emerging technology that can treat wastewater and also recover resources such as energy in the form of electricity/hydrogen gas and nutrients such as nitrogen and phosphorus compounds. Microbial electrolysis cell (MEC) is a type of BES that, in the presence of an additional voltage, can treat wastewater and generate hydrogen gas. This is a promising approach for wastewater treatment and value-added product generation, though it may not be sustainable in the long run, as it relies on fossil fuels to provide that additional energy. Thus, it is important to explore alternative renewable resources that can provide energy to power MEC. Waste heat is one such resource that has not been researched extensively, particularly at the low-temperature spectrum. This was utilized as a renewable resource by converting waste heat to electricity using a device called thermoelectric generator (TEG). TEG converted simulated waste heat from an anaerobic digester to power an MEC. The feasibility of TEG to act as a power source for an MEC was investigated and its performance compared to the external power source. Various cold sources were analyzed to characterize TEG performance. To explore this integrated TEG-MEC system further, a hydraulic connection was added between the two systems. Wastewater was used as a cold source for TEG and it was recirculated to the anode of the MEC. This system showed improved performance with both systems mutually benefitting each other. The operational parameters were analyzed for the optimization of the system. The integrated system could generate hydrogen at a rate of 0.36 ± 0.05 m3 m-3 d-1 for synthetic domestic wastewater treatment. For the practical application, it is necessary to estimate the cost and narrow the focus on the functions of the system. Techno-economic analysis was performed for MEC with cost estimation and net present value model to understand the economic viability of the technology. The application niche of the BES was described and directions for addressing the challenges towards a full-scale operation were discussed. The present system provides a sustainable method for wastewater treatment and resource recovery which can play an important role in human health, social and economic development and a strong ecosystem.Doctor of Philosophy
An average person produces about 50-75 gallons of wastewater every day. In addition to the households, wastewater is generated from industries and agricultural practices. As the population increases, the quantity of wastewater production will inevitably increase. To keep our rivers and oceans clean and safe, it is essential to treat the wastewater before it is discharged to the water bodies. However, the conventional wastewater treatment is a very energy (and thus cost) intensive process. For low-income and developing parts of the world, it is difficult to adapt the technology everywhere in its present form. Furthermore, as the energy is provided mostly by fossil fuels, their limited reserves and harmful environmental effects make it critical to find alternative methods that can treat the wastewater at a much lower energy input. For a circular and sustainable economy, it is important to realize wastewater as a resource which can provide us energy, nutrients, and water, rather than discard it as a waste. Bioelectrochemical systems (BES) is an emerging technology that can simultaneously treat wastewater and recover resources in the form of electricity/hydrogen gas, and nitrogen and phosphorus compounds. Microbial electrolysis cell (MEC) is a type of BES that is used to treat wastewater and generate hydrogen gas. An additional voltage is supplied to the MEC for producing hydrogen. In the long run, this may not be sustainable as it relies on fossil fuels to provide that additional energy. Thus, it is important to explore alternative renewable resources that can provide energy to power MEC. Waste heat is a byproduct of many industrial processes and widely available. This was utilized as a renewable resource by converting waste heat to electricity using a device called thermoelectric generator (TEG). TEG converted simulated waste heat from an anaerobic digester to power an MEC. The mutual benefit for MEC and TEG was also explored by connecting the system electrically and hydraulically. Cost-estimation of the system was performed to understand the economic viability and functions of the system were developed. The present system provides a sustainable method for wastewater treatment and resource recovery which can play an important role in human health, social and economic development and a strong ecosystem.
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Das, Sayan. "Study of Thermoelectric Transport Properties of Doped and Vacancy Induced BiCuSeO." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4732.
Повний текст джерелаАнотація:
About 70% of the heat generated for energy production is wasted and thermoelectric generators can capture this waste heat and convert it into useful electricity. The stability at high temperature in the ambient atmosphere is much needed for the thermoelectric materials for the generator applications, as a result, oxides are the materials of choice. BiCuSeO is a thermoelectric material having cheap, earth-abundant elements and stable at high temperatures. It has a high Seebeck coefficient low thermal conductivity but high electrical resistivity due to its low hole concentration. The effect of Bi vacancies coupled with O vacancies on the thermoelectric properties of BiCuSeO was studied. The Bi vacancies highly reduce the Seebeck coefficient which is partially recovered by the O vacancy. Both the electrical resistivity and Seebeck coefficient decreased with increasing vacancy content. As a result of the decreased electrical resistivity and moderate Seebeck coefficient, the highest power factor of 0.41 mW/m-K2 at 773 K was obtained for the Bi0.92CuSeO0.98 and Bi0.92CuSeO0.98 samples. The zT in the samples with vacancies could not be improved because of the higher thermal conductivity compared to the pristine sample. The transition metals Mn and Zn was doped at the Bi site to decrease the electrical resistivity in addition to that local magnetic moments of Mn can improve the Seebeck coefficient. Since both the Mn and Zn have similar chemical and atomic properties with Cu, the formation energies of the dopants were calculated to determine the probable doping site. The similar formation energies of doping Zn at Bi site and Cu site enable Zn to dope both at the Cu and the Bi site while Mn is more probable to dope at Bi site. The Seebeck coefficient and electrical resistivity monotonically decrease with increasing doping fraction which indicates that Zn is primarily doped at the Bi site and Mn+2 is doped at the Bi site. Both the dopants exhibit small polaron hopping conduction and localization of charge. The highest power factor of 0.35 mW/m-K2 and highest zT of 0.48 was achieved for Zn-doped samples while that of the Mn-doped samples was 0.28 mW/m-K2 and 0.4 respectively. Pb and Na were dually doped at the Bi site of BiCuSeO to improve the carrier concentration without deteriorating the mobility. The increase in the carrier concentration due to Pb doping decreases both the Seebeck coefficient and the electrical resistivity of the samples. As a result of low thermal conductivity and high power factor of 0.53 mW/m-K2, the highest power factor of 0.63 was obtained for the Bi0.905 Na0.015Pb0.08CuSeO sample at 773 K.
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Lin, Yi-Lun, and 林逸倫. "A Study of Waste Heat Recovery Power Transformer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/2jmt8v.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
能源與冷凍空調工程系碩士班
98
The purpose of this study is to develop building can be equipped with power transformers, apart from indirect heat loss of power supply, the system heat recovery feasibility robin to verify power transformer not only has high-voltage transformation for home voltage effect. It can turn the heat produced by the body to use the principles of the room temperature by circulating water into more hot water, bath shower supply staff to work purposes or other purposes require the use of hot water . Of power transformers for the plant or building, hotel user must have the high-voltage electrical equipment, power transformers in China the average efficiency is about 98%, such as the 1000KVA transformer set its load 1000KW, its efficiency was 98.3%, calculate the transformer copper loss plus the loss of total iron loss is about 17KW, heat loss of this magnitude will bring high temperature atmosphere, causing a large number of air-conditioning system load, the global warming is more serious, such heat transmission from the power transformer would reduce the water circulation system cost effectiveness better than other electric water heater through the consumption of electrical energy converted to heat several times higher than the role of such systems to the power transformer substation for the purpose of heat source can be achieved, the added value they receive. This research is carried out through to brass mount transformer insulating oil to room temperature water in the coil in the loop, transformer coils and absorb the heat generated by core, recovery and storage of the experimental use of high-voltage power transformers, low voltage power transformer (7.5 KVA) of two different specifications of transformers, power supply via the transformer to operate, with the most suitable for the recovery of various occasions. In order to test this experiment a much wider range of heating source, fast real-time, when the heating source in the test used by a variety of time use or a combination of high pressure (low) power transformers, solar panels, a power-storage function of lead-acid batteries, common electricity plug. After deriving the most economical recycling system, following the experiment to test further to obtain the thermal effects of the data system for research, from actually results indicate assumption water recovery efficiency is 50%, in the manufacture of hot water , can be 17.5 liters of water at room temperature increases the average temperature from 20 ℃ to 50 ℃, heating effect of 12.5 kJ of heat, just took about 34 minutes. Can be proved from the above data, the consumption of power transformers can really heat recovery unit to the heating of the benefit.
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Chen, Yeh-Cheng, and 陳彥誠. "Intelligent Radioactive Waste Process System for Nuclear Power Plant Decommissioning." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/a485d8.
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