The demand for electricity of a particular location can vary significantly based on season, ambient temperature, time of the day etc. High demand can result in very high wholesale price of electricity. The reason for this is very short operating duration of peaking power plants which require large capital investments to establish. Those power plants remain idle for most of the time of a year except for some peak demand periods during hot summer days. This process is inherently inefficient but it is necessary to meet the uninterrupted power supply criterion. With the advantage of new technologies, demand response can be a preferable alternative, where peak reduction can be obtained during the short durations of peak demand by controlling loads. Some controllable loads are with thermal inertia and some loads are deferrable for a short duration without making any significant impact on users' lifestyle and comfort. Demand response can help to attain supply - demand balance without completely depending on expensive peaking power plants. In this research work, an incentive-based model is considered to determine the potential of peak demand reduction due to the participation of residential customers in a demand response program. Electric water heating and air-conditioning are two largest residential loads. In this work, hot water preheating and air-conditioning pre-cooling techniques are investigated with the help of developed mathematical models to find out demand response potentials of those loads. The developed water heater model is validated by comparing results of two test-case simulations with the expected outcomes. Additional energy loss possibility associated with water preheating is also investigated using the developed energy loss model. The preheating temperature set-point is mathematically determined to obtain maximum demand reduction by keeping thermal loss to a minimal level. Case studies are performed for 15 summer days to investigate the demand response potential of water preheating. Similarly, demand response potential associated with pre-cooling operation of air-conditioning is also investigated with the help of the developed mathematical model. The required temperature set-point modification is determined mathematically and validated with the help of known outdoor temperature profiles. Case studies are performed for 15 summer days to demonstrate effectiveness of this procedure. On the other hand, total load and demand response potential of a single house is usually too small to participate in an incentive-based demand response program. Thus, the scope of combining several houses together under a single platform is also investigated in this work. Monte Carlo procedure-based simulations are performed to get an insight about the best and the worst case demand response outcomes of a cluster of houses. In case of electrical water heater control, aggregate demand response potential of 25 houses is determined. Similarly, in case of air-conditioning control (pre-cooling), approximate values of maximum, minimum and mean demand reduction amounts are determined for a cluster of 25 houses. Expected increase in indoor temperature of a house is calculated. Afterwards, the air-conditioning demand scheduling algorithm is developed to keep aggregate air-conditioning power demand to a minimal level during a demand response event. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm. / Master of Science

En réponse à l’évolution de la réglementation thermique, les bâtiments tendent à être mieux isolés et plus étanches, diminuant leurs besoins de chauffage. La ventilation, nécessaire pour garantir la qualité de l’air intérieur, représente une perte énergétique non négligeable. De plus, les besoins d’eau chaude sanitaire (ECS) deviennent prépondérants par rapport à ceux de chauffage. Dans ce contexte, les systèmes solaires thermiques peuvent fournir une part importante des besoins du bâtiment. Ce travail étudie ainsi un système solaire thermique qui produit de l’ECS et préchauffe l’air de ventilation. Le principe de fonctionnement est d'abord analysé expérimentalement. Le concept se présentant prometteur, une co-simulation entre Dymola (langage Modelica) et EnergyPlus permet d'étudier plus en détail les performances du système dans son environnement (le bâtiment) pour différents hypothèses et paramètres de fonctionnement. Les résultats montrent un meilleur rendement des capteurs et du ballon par rapport à un CESI classique, ainsi qu’une augmentation de la fraction solaire pour la production simultanée d’ECS, de préchauffage d’air et de chauffage / Thermal regulation demands the construction of more efficient buildings that use less energy, in particular for heating. Air renewal, which is necessary to guarantee indoor air quality, represents a significant thermal loss in the energy balance of efficient buildings. Moreover, domestic hot water (DHW) needs become more important than heating needs. In this context, solar thermal systems can produce a significant part of the thermal needs in buildings. Indeed, this work studies a solar thermal system producing DHW and fresh air preheating. The operating principle is first analysed experimentally. As the system seems promising, a co-simulation between Dymola (using the Modelica language) and EnergyPlus is used to do a detailed study of the system performances in a building based on different assumptions and for different design parameters. The results show a better collector yield and tank efficiency regarding a classic solar water heater, as well as an increase of the solar fraction including DHW production, air preheating and space heating

Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2017-07-03T15:13:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Fernanda_Souza.pdf: 933831 bytes, checksum: 43c42fb14ee5a88d9333bab1201bcb35 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-07-03T17:53:33Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Fernanda_Souza.pdf: 933831 bytes, checksum: 43c42fb14ee5a88d9333bab1201bcb35 (MD5) / Made available in DSpace on 2017-07-03T17:53:33Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Fernanda_Souza.pdf: 933831 bytes, checksum: 43c42fb14ee5a88d9333bab1201bcb35 (MD5) Previous issue date: 2016-02-26 / Sem bolsa / O Brasil é o terceiro maior produtor e segundo maior exportador mundial de carne de perus. Mesmo com todo o prestígio e importância dessa cadeia produtiva, existem poucos trabalhos científicos voltados para ela, principalmente quando se trata de incubação de ovos. O manejo das matrizes no campo é de extrema importância para os resultados de uma empresa, assim como o manejo dos ovos e dos peruzinhos de um dia nos incubatórios. Esta dissertação trata do processo de incubação de ovos férteis de matrizes de perus visando obterem-se melhores resultados para incubatórios industriais. No experimento realizado foi avaliada a influência de três tratamentos (controle, 3 horas e 12 horas) de pré-aquecimento de ovos antes da estocagem, técnica que surge como alternativa para suprimir os efeitos negativos de uma estocagem prolongada. Paralelamente foram avaliados dois períodos de estocagem (5 e 12 dias) de ovos, cuja prática é cada vez mais utilizada em incubatórios por questões de fluxo de produção e padronização de lotes. As variáveis analisadas foram eclosão total, perda de peso do ovo até o momento da transferência (PPOT), relação peso do ovo e peso do peruzinho (RPO/RPP), peruzinhos eliminados, mortalidade embrionária por período de incubação e mortalidade total. Entre os tratamentos de pré-aquecimento, observou-se que o de 12 horas apresentou maior percentual de eclosão, menor percentual de peruzinhos eliminados e menor mortalidade da terceira e quarta semana de incubação. Em relação ao período de estocagem, o de 5 dias de duração proporcionou ganhos significativos para as variáveis de porcentagem de eclosão, mortalidade na fase final e mortalidade total quando comparado ao estoque de 12 dias. As variáveis PPOT e RPO/RPP mantiveram seus resultados dentro do percentual desejado pela indústria, demonstrando que não foram influenciadas negativamente por nenhum dos tratamentos de pré-aquecimento, nem pelos períodos de estocagem. / This dissertation Brazil is the third largest producer and second largest exporter of turkey meat. Even with all the prestige and importance of the supply chain, there are few scientific studies related to it, especially when it comes to egg incubation. The management of arrays in the field is of utmost importance to the results of a company, as well as the handling of eggs and poults a day in hatcheries. This paper deals with the incubation process fertile eggs from turkeys matrices order to obtain the best results for industrial hatcheries. In the experiment carried out to study the effect of three treatments (control,3 hours and 12 hours) preheating eggs before storage technique which is an alternative to suppress the negative effects of prolonged storage. In parallel we were evaluated two periods of storage (5 and 12 days) eggs, which practice is ever more utilized in hatcheries for production and standardization issues flow of lots. The variables analyzed were all hatching egg weight loss until the time of transfer (PPOT), egg weight ratio and weight poults (RPO/RPP), eliminated poults, embryonic mortality incubation period and total mortality. Among the preheat treatment, it was observed that the 12 hours had a higher percentage hatching, a lower percentage of poults eliminated and reduced mortality of the third and fourth week of incubation. Regarding the storage period, the 5 day period provided significant gains for hatching percentage of variables, mortality in the final phase and total mortality when compared to the stock of 12 days. The pPot and RPO / RPP results variables maintained within the industry desired percentage, showing that they were not negatively affected by any of the preheat treatment, or by storage periods.

Dans cette thèse j'étudie le reheating de l'Univers inflationnaire. Cette ère fait le lien entre l'inflation de l'Univers et le modèle du Big- Bang chaud. Pendant celle-ci, l'Inflaton se désintègre en matière qui, via ses propres intéractions, thermalise et donne une description statistique au contenu de l'Univers. Ce travail est réalisé dans le cadre d'une théorie quantique des champs utilisant des méthodes hors équilibre telle que l'action effective 2-Particule-Irreductible permettant de faire face aux difficultés de la théorie quantique des champs hors équilibre traditionelle. J'étudie premièrement le cas où la matière produite peut être décrite par des champs scalaires puis par des degrés de liberté fermioniques, où l'approximation classique n'existe pas. Je développe l'action effective à l'ordre sous dominant d'un développement non perturbatif en inverse du nombre de champs de matière ce qui permet d'explorer des théories où la matière est fortement couplée à elle-même. Dans une deuxième partie j'étudie la décohérencedes fluctuations primordiales de densité. L'inflaton peut être vu comme un condensat quantiquement cohérent et sa désintégration comme une décohérence de celui-ci. Cette décohérence et perte de pureté est fortement liée à la perte d'information qu'un observateur a sur le système si il se restreint au sousespace Gaussien des fonctions de corrélations. Cette étude montre que, même dans le cadre peu habituel où le système n'est pas en intéraction avec un environnement extérieur incohérent et/ou thermique, celui-ci perd sa pureté et sa cohérence initiale au profit d'une production du nombre de degré de liberté ou d'entropie.

[pt] Este trabalho tem por objetivo principal a avaliação de desempenho de um sistema piloto de preaquecimento dos motores da central termelétrica Gera Maranhão, via energia solar térmica, em Miranda do Norte, Maranhão, através de uma simulação numérica. Cinco subsistemas independentes, cada um responsável pelo preaquecimento de um motor Wartsila 20V32 de 8,73 MW, foram construídos, somando um total de 500 coletores solares instalados e uma superfície de captação solar total de 1000 metros quadrados. Uma estação meteorológica com sensores de radiação solar global, difusa, direta e temperatura ambiente foi posicionada do lado dos sistemas para medir as condições ambientais na região. A simulação do desempenho do sistema solar foi efetuada ao longo de um ano com dados de radiação solar da estação meteorológica de Buriticupu, no Maranhão, dados que mais se aproximam dos dados disponíveis de Miranda do Norte. Correlações para transformar a radiação global medida numa superfície horizontal para uma superfície inclinada foram selecionadas após uma revisão bibliográfica dentre as disponíveis na literatura. Diferentes cenários de controle do acionamento das bombas de água foram comparados a fim de determinar a melhor configuração de operação. A influência da temperatura de preaquecimento dos motores no desempenho do sistema solar foi avaliada também. Os resultados da simulação foram comparados com os resultados obtidos via o método F-CHART. Uma participação média anual da energia solar de 11,5 por cento foi encontrada para o preaquecimento dos motores levando a uma redução de 24693 kg/ano de óleo combustível usado na caldeira do sistema de preaquecimento dos motores da usina termelétrica. / [en] The present work has as main objective the performance evaluation of a pilot system for preheating the engines of Gera Maranhão power plant, in Miranda do Norte, state of Maranhão, via thermal solar energy using a numerical simulation. Five independent subsystems, each one responsible for the preheating of a Wartsila 20V32 internal combustion engine of 8.73 MW, were installed. These systems amount five hundred solar collectors, with a total solar collecting area of 1000 square meters. A meteorological station with sensors for global, diffusive and beam solar radiation, as well as ambient temperature recorders, was placed by the side of the system in mode to measure ambient condition in the area. The simulation of the solar system performance was processed over a year with data of solar radiation for a meteorological station of Buriticupu, state of Maranhão, Brazil. Correlations to transform the global radiation measured on a horizontal plane to a sloped plane were selected, following a selection from a literature review. For the control of the water pumps, different scenarios were compared in order to determine the best operational configuration. The influence of engine preheating temperature in the performance of the solar system was also evaluated. Simulation results were compared with results obtained with the F-CHART method. An annual average solar energy contribution of 11.5 percent was found for the preheating of the engines. This resulted in a reduction of 24693 kg per year of fuel oil used in the boiler of the traditional preheating system of the power plant.

Made available in DSpace on 2014-06-11T19:24:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-11-24Bitstream added on 2014-06-13T18:52:41Z : No. of bitstreams: 1 godoy_wl_me_bauru.pdf: 10498563 bytes, checksum: a471999a6640d177cb8963731e9bafe8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A identificação e a qualificação dos constituintes microestruturais de uma junta soldada são de grande importância pela relação que existe entre a microestrutura do cordão e as propriedades mecânicas, particularmente a tenacidade. Trabalhando com variações nos parâmetros de pulso, corrente de pico e tempo de pico, e também na temperatura de pré-aquecimento, foram quantificados os constituintes ferrita acicular e microfases presentes no metal de solda; sendo ambos considerados controladores da tenacidade. Os resultados deste trabalho demonstraram que aumentou a quantidade de ferrita acicular para os menores níveis dos parâmetros de pulso e da temperatura de pré-aquecimento. Quanto às microfases, ocorreu uma redução na quantidade à medida que se elevaram os níveis dos parâmetros de pulso e da temperatura de pré-aquecimento. Observou-se, também, qual foi a influência da velocidade de resfriamento na microestrutura final do metal de solda. Foi utilizado o processo de soldagem a arco elétrico com proteção gasosa, no modo pulsado e arame tubular. A soldagem foi realizada em chapa de aço estrutural de alta resistência e baixa liga (COS-AR 50), com chanfro em X e ângulo de 30º. Como metal de adição foi utilizado o arame tubular de fluxo metálico E70C-6M, com diâmetro de 1,2 mm. / The identification and qualification of the microstructural constituents present in the welded joint are very important for the relationship between the microstructure of the weld beads with the mechanical properties, particularly toughness. Working with variations of pulse parameters, peak current and peak time, and also preheating temperature, had been quantified the constituents acicular ferrite and microphases present in weld metal; being both considered controllers of toughness. The results of this work demostrated that greater amounts of acicular ferrite had been occurred in the lowest levels of pulse parameters and preheating temperature. As for microphases, it has a reduction of the amount with the increase of pulse parameters and preheating temperature. It was observed, also, the influence of the cooling speed in the final microstructure of the weld metal. The samples were welded by the metal gas arc welding, using pulsed arc and tubular wire. As metal base was used HSLA structural steel plate (COS-AR 50), with X-groove and bevel angle 30º. The addition metal was the tubular metal-cored wire E70C-6M with diameter of 1.2 mm.

As the largest source of iron in North America, and as the largest energy consumer in the modern integrated steel mill, the blast furnace is a critical part of modern ironmaking. Any improvements that can be made to the efficiency or emissions of the blast furnace can have far reaching environmental impacts as the production of one ton of steel results in 1.85 tons of carbon dioxide emissions. Given the concerted push to reduce greenhouse emissions, novel technologies are needed to improve efficiency. In this study the injection of preheated natural gas, precombusted syngas from a variety of feedstocks, and hydrogen injection were all modeled using computational fluid dynamics, from the tuyere through the shaft of the furnace. The impacts of these various operational changes were evaluated using CFD calculated analogs for Raceway adiabatic flame temperature (RAFT), top gas temperature (TGT), and coke rate (CR). Results indicate that a reduction of 3% to 12% in CO2 emissions is possible through the implementation of these technologies, with each possessing distinct benefits and drawbacks for industrial implementation.

This thesis deals with usage of hybrid technology Laser-TIG for welding of boron enhanced steel 22MnB5. This thesis evaluates the influence of preheating using technology of TIG arc welding to a weld quality in comparison with laser welds. In practical part of thesis there were 1,8 mm metal sheets of 22MnB5 welded. This metal sheet specimens were welded by using constant parameters of laser with varying parameters of TIG technology. There were 12 specimens of sheet metal created including 3 specimens using only laser and 9 specimens using Laser-TIG hybrid technology while varying magnitude of current (I=20 A, 40 A a 60 A). Welds created this way were evaluated by tensile test and strength limits compared. Then metalografic survey was carried out examining macro and microstructure. Results of metalografic survey were confronted with Vickers hardness test.

Sveriges och världens industrier står inför stora omställningar gällande energianvändning och klimatavtryck. Johnson Metall AB jobbar ständigt med miljöarbete och har identifierat gasolanvändningen i produktionen som ett ställe där stora miljövinster går att göra. Examensarbetet avgränsas till att enbart titta på alternativa förvärmningstekniker till skänkar.Syftet med rapporten är att undersöka 3-5 alternativa förvärmningstekniker till den gasoluppvärmning som används i dagsläget. Det är viktigt att en alternativ lösning gör så att nuvarande produktkvalitet bibehålls samtidigt som en alternativ lösning bidrar till ett lägre klimatavtryck, det är även viktigt att priset på produkterna inte går upp allt för mycket.För att genomföra examensarbetet har metoderna litteratursökning, Double Diamond, nulägesanalys, komparation och kriterieviktsmetoden använts. För att skapa en bild över uppvärmningsförloppet görs en testmätning som jämförs med teoretiska samband.Utbudet av klimatavtrycksminskande teknik är relativt stor och fortsätter att växa, däremot råder det brist på incitament att byta teknik. Det krävs stora investeringar i ny teknik som är relativt obeprövad. Bränslen som skulle kunna nyttjas blir indirekt reserverade för andra teknikslag till följd av konkurrensen på bränslemarknaden. I dagens läge ligger risktagandet i övergången till ny klimatneutral teknik hos industrin.Det alternativ som har störst potential är en elektrisk lösning. Förändringar i anläggningen kommer inte innebära någon större inverkan i produktionen. Konsekvenserna av att byta förvärmningsteknik är att produkterna förmodligen kommer öka i pris, men att produkten också får ett lägre klimatavtryck. / Due to the consequences of global warming the industries of the world are facing new challenges. Johnson Metall AB is continuously working with ways to reduce their environmental footprint. Johnson Metall AB has identified use of liquid petroleum gas (LPG) as a source where great environmental gains can be made. The thesis limits itself to only look at LPG use in ladle preheating.The purpose of the thesis is to investigate 3-5 alternative ladle preheating technologies instead of the current LPG preheating of ladles. It is important that an alternative solution keeps the current quality of the products and contributes to lower emissions, it is also important that the price of the products doesn’t increase too much. In order to investigate available options the following methods have been used: literature study, double diamond, current situation analysis, comparison method, and the criterion weight method. In order to create a picture of the heating of ladles, an evaluation measure is performed and compared with theoretical concepts. Climate friendly alternatives are present on the market and are continuously improving, however the incentives to invest in new technologies are few. From the industries perspective the available options are expensive and relatively untested. Fuels that are viable options are taken from consideration due to hard competition with other markets. Moving to alternative fuels is a risky business with few guarantees for the foundry industries. The alternative with the biggest potential is an electric solution. Changes in the facility will not result in any major interference in production. The consequences of changing ladle preheating technology will probably be an increase in the price of the products, however the product will be more environmentally friendly.

Yes / Scale formation of carbonates and sulphates is one of the most well-known types of crystallization fouling in heat exchangers. Tackling crystallization fouling in Once-Through Multistage Flash Desalination (MSF-OT) is one of the most challenging tasks in the desalination industry. In this paper, a fouling model is developed and then incorporated into a MSF model to investigate the fouling behaviour under variable seawater temperature. The proposed dynamic model investigates the crystallization of calcium carbonate and magnesium hydroxide at the inside tube surface areas by considering the attachment and removal mechanisms. The results show that the fouling rate is higher at high constant seawater temperature. Overall, the fouling rate is lower at the seasonal variation of the seawater temperature, resulting in a higher performance ratio (PR). The results also show that although the brine heater duty increases in winter due to low seawater temperature, the drop of fouling rate in cold months may save some energy.