Made available in DSpace on 2014-10-09T12:25:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:06Z (GMT). No. of bitstreams: 1 02233.pdf: 1898081 bytes, checksum: ca8d5eb71d409e24aba2146df83dd874 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T14:26:55Z No. of bitstreams: 0 / Made available in DSpace on 2015-04-10T14:26:55Z (GMT). No. of bitstreams: 0 / Neste trabalho, vidros contendo um resíduo industrial denominado lama vermelha, foram desenvolvidos e caracterizados. Foi utilizada a quantidade mínima de 60% em massa de lama vermelha na produção dos vidros para promover a utilização desse resíduo. De acordo com os resultados de difração de raios X obtidos, observa-se que é possível produzir materiais a partir da lama vermelha com fases amorfas consideráveis, embora fases cristalinas referentes ao Fe originário do resíduo estejam presentes. O material denominado 60L40S, o qual possui 60% em massa de lama vermelha na sua composição nominal, apresentou as melhores propriedades dentre as composições estudadas, porém apresentou também alta temperatura de fusão. Ajustes na composição desse material foram realizados buscando diminuir essa temperatura. Os resultados mostram que os ajustes foram satisfatórios no desempenho de diminuir a temperatura de fusão, porém perdas na propriedade química desse material foram observadas. Elementos comumente encontrados na composição química de rejeitos nucleares foram adicionados aos vidros produzidos neste trabalho visando estudar os efeitos dessa adição nas propriedades químicas e térmicas desses materiais. Foi observado que é possível adicionar até 15% em massa de elementos simuladores aos materiais produzidos e essa adição promove a diminuição da temperatura de fusão. Acima de 15% em massa os elementos adicionados se precipitam na estrutura do material. Foi observado que, embora haja perdas na durabilidade química do material 60L40S após a adição dos elementos simuladores, esse material, quando em contato com água, mantém os elementos simuladores confinados em sua estrutura. Esse resultado é promissor, pois sugere que o material 60L40S é capaz de imobilizar em sua estrutura elementos provenientes de rejeitos nucleares. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

D.Ing. / The thesis describes the development, installation, and testing of a neural network-based steam temperature controller for power plant boilers. Attention is focussed on the mechanical and thermodynamic aspects of the control problem, on the modelling and control aspects of the neural network solution, and on the practical and operational aspects of its implementation. A balance between theoretical and practical considerations is strived for. Experimental data is obtained from an operational coal fired power plant. As a starting point, the importance of good steam temperature control is motivated. The sensitivity of heated elements in boilers to changes in heat distribution is emphasized, and it is shown how various factors influence the heat distribution. The difficulties associated with steam temperature control are discussed, and an overview of developments in advanced steam temperature control on power plant boilers is given. The suitability of neural networks for process modelling and control are explored and the error backpropagation technique is shown to be well suited to the steam temperature control problem. A series of live plant tests to obtain modelling data is described and specific attention is given to discrepancies in the results. The prOcess of selecting the ideal network topology is covered and improvements in modelling accuracy by selecting different model output schemes are shown. The requirements for improving steam temperature control are listed and the philosophy of optimal heat distribution (OHD) control is introduced. Error backpropagation through the heat transfer model is utilized in an optimizer to calculate control actions to various fire-side elements. The scheme is implemented on a power boiler. It is shown that the optimizer manipulates control elements as expected. Problems with fuel-topressure oscillations and erroneous fuel flow measurement are discussed. Due to process oscillations caused by OHD control, a reduction in control quality is evident during mill trips and capability load runbacks. Substantial improvements over normal PID control however, are evident during load ramps.

Este trabalho aborda o desenvolvimento de um sistema de controle de temperatura para um aquecedor de passagem de água a gás. O sistema de controle Controlgás é apresentado e comparado ao sistema de controle típico, usado em aquecedores de passagem convencionais. São apresentadas as características e objetivos do projeto Controlgás, o qual serviu de base para o desenvolvimento deste trabalho. É apresentada uma fundamentação teórica sobre técnicas de controle para compensação de variações paramétricas e de atrasos de transporte, bem como uma revisão sobre as principais soluções já desenvolvidas para o controle de temperatura da água em aquecedores de passagem. A bancada experimental, contendo o aquecedor e o sistema de controle, utilizada em trabalhos anteriores, foi reestruturada e instrumentada com sensores de temperatura na entrada e na saída de água e com sensores que detectam a presença de chama e de fluxo de água. Foi desenvolvida uma servo-válvula que permite a regulagem automática da vazão de gás. Desenvolveu-se um circuito de potência para o acionamento dos atuadores (solenoides e servo-válvula) da bancada, assim como algoritmos que geram os sinais adequados para seu funcionamento. Foi feita a identificação do processo e o modelo da servo-válvula foi obtido por meio da análise de ensaios experimentais. O modelo do sistema completo foi desenvolvido no programa Simulink, onde foram feitas simulações do comportamento dinâmico do sistema proposto. O sistema foi implantado experimentalmente e foi capaz de convergir para as temperaturas de referência durante os ensaios. / This work addresses the development of a temperature control system for a gas tankless water heater. The Controlgás control system is presented and compared to typical control systems used in regular tankless water heaters. The characteristics and objectives of Controlgás project, which formed the basis for the development of this work, are presented. A theoretical foundation on control techniques for compensation of parametric variations and transport delays is presented, as well as a review of the main solutions already developed for the control of water temperature on tankless water heaters. The experimental set containing the heater and the control system used in previous work was restructured and instrumented with temperature sensors at the water's input and output and with sensors which detect the presence of flame and the water flow. A servo-valve that allows automatic adjustment of the gas flow was developed. A power circuit was created to drive the actuators (solenoids and servo-valve) of the set, as well as algorithms that generate the appropriate signals for its operation. The process identification and the servo-valve‟s model were obtained through experimental analysis. The system‟s complete model was developed in Simulink, where simulations of the dynamic behavior of the proposed system were made. The system was implemented experimentally and was able to converge to the reference temperatures during the tests.

Surface temperature control of a thin plate is investigated. Temperature is controlled on one side of the plate using the other side temperature measurements. This is a decades-old problem, reactivated more recently by the awareness that this is a fractional-order problem that justifies the investigation of the use of fractional order calculus. The approach is based on a transfer function obtained from the one-dimensional heat conduction equation solution that results in a fractional-order s-domain representation. Both the inverse problem approach and the fractional controller approach are studied here to control the surface temperature, the first one using inverse problem plus a Proportional only controller, and the second one using only the fractional controller. The direct problem defined as the ratio of the output to the input, while the inverse problem defined as the ratio of the input to the output. Both transfer functions are obtained, and the resulting fractional-order transfer functions were approximated using Taylor expansion and Zero-Pole expansion. The finite number of terms transfer functions were used to form an open-loop control scheme and a closed-loop control scheme. Simulation studies were done for both control schemes and experiments were carried out for closed-loop control schemes. For the fractional controller approach, the fractional controller was designed and used in a closed-loop scheme. Simulations were done for fractional-order-integral, fractional-order-derivative and fractional-integral-derivative controller designs. The experimental study focussed on the fractional-order-integral-derivative controller design. The Fractional-order controller results are compared to integer-order controller’s results. The advantages of using fractional order controllers were evaluated. Both Zero-Pole and Taylor expansions are used to approximate the plant transfer functions and both expansions results are compared. The results show that the use of fractional order controller performs better, in particular concerning the overshoot.

Providing conditioned and fully controlled room is the final goal for having a comfortable building. But on the other hand making smart controllers to provide the required cooling or heating load depending on occupants' real time feeling is necessary. This study has emphasized on finding a meaningful and steady state parameter in human body that can be interpreted as comfort criterion which can be expressed as the general occupants' sensation through their ambient temperature. There are lots of researches on human physiological behavior in different situations and also different body parts reaction to the same ambient situation. Body parts which have the biggest reliable linear fluctuation to the changes are the best subject for this research. For these tests, wrist and palm have been selected and their temperatures on different people have been measured accurately with thermal camera to follow the temperature trend on various comfort levels. It is found that each person reaches to his own unique temperature on these two spots, when he/ she feels comfortable, or in other word each person's body temperature is a precise nominate for comfort feeling of that individual. So in future by having this unique comfort parameter and applying them to the HVAC system temperature control, controlling the dynamic temperature and correlating the indoor condition depending on the occupants instant thermal comfort level, would be a rational choice to bring convenience while energy has been saved more.

In this work is developed a proposal for extrusion head for extruding plastic wires of small diameter. There is a new conceptual design of cooling, which allows shape extruded products already in the extrusion head and thereby eliminates the need for large cooling tanks. To determine the optimal design is used software named Virtual Extrusion Laboratory, which is used in practice for the simulation of the extrusion process. Then it is experimentally determined behavior of plastic material, when the temperature of the melt in the extrusion head is reduced.

The aim of this thesis is to investigate the Air Conditioning system in a heavy duty truck and to develop a control strategy for the case when low cooling capacity is needed from the AC-system. A model of the AC-system was developed in order for an efficient controller to be designed. The model was designed to comprise of all the basic behaviours that the AC- system has, rather than to be an exact model of the system. As the AC-system showed to be very complex, a number of limitations in the model had to be made. The AC-system has two temperature sensors and is actuated by turning the AC- compressor on or off. Two different control strategies were tested for the control of the AC-compressor. The first was to use a controller to directly control the compressor clutch and the second one utilised a pulswidth modulated control structure were the controller stated the pulswidth to be used. Both control structures were implemented in the computer model, the AC-rig and in a truck in a climate chamber. Both control strategies showed to fulfil the demands on the system in the somewhat idealistic circumstances during which they were tested.

In an abundance of industries, production lines and facilities, a correct indoor climate is an integral part to ensure the quality of the products and also very important for its occupants. To ensure a high quality air climate it is not enough to control the air temperature, air humidity is of at least equal importance. Most heating, ventilation and air conditioning systems (HVAC), are based on multiple treatment steps that each change both temperature and humidity. Due to the correlation between the temperature and relative humidity this results in system control difficulties, and unnecessary realignments to achieve the desired outputs. The novel Shortest path enthalpy change system (SPEC), developed by AirWaterGreen (AWG) with Controlled vapor pressure technology (CVP), aims to eliminate these problems. This is done by utilizing a method that may achieve the desired air quality with only one conditioning step, transferring heat and humidity simultaneously to or from the air. To validate this technology the work of this thesis is focused on producing a viable simulator model with verification, performed by comparing to a prototype system with the same technology. By verifying the simulator, it is also possible to continue development of the system by implementing system controllers within the Simulink environment. This provides the opportunity to ultimately obtain a highly efficient HVAC system with accurate setpoint control. In addition, the possibility of optimizing system dimensions is also investigated to allow for specific case configurations. The results show that high simulator accuracy is achievable, leading to a high confidence in the results, and showing that a PID or even proportional feedback controller is able to realize satisfactory system control. The optimization of dimensions shows that parallel computing is a fast way to reduce the amount of possible configurations that satisfy specific criteria. To support further development of the control and optimization of the system and ultimately hardware implementation, this thesis suggests points of interest for future work. These points include the improvement of ancillary simulator systems and further development of the pads physical equations, to increase the accuracy of process simulations, and the continued development of more complex controllers as well as their hardware implementation. Lastly, while focus of this thesis has been on the development of a functioning and controllable system, an important addition would be a study on the energy usage of the system and identifying points of interest for decreasing the total energy used from the system.

The aim for this thesis is to explore the possibility to save both water and energy in showers. Through a quicker, more responsive and precise shower faucet using digital thermometers and stepper motors. A faucet has two input pipes with cold and hot water respectively. To reach a desired shower temperature; a single thermometer is needed, to measure the mixed water temperature. Using this information, two motors will control two valve until the desired temperature is reached. To maintain the desired temperature throughout the shower session, the temperature should be continuously monitored and when temperature disturbance occurs, the valves should compensate for it. To achieve this a demonstrator was made. The demonstrator uses stepper motors connected to valves to control the flow through a hot and cold water pipe. The system reads the temperature of the output water continuously and makes appropriate changes to the position of the valves. Due to safety concerns, no water was used in the testing of the demonstrator. The theoretical response time of the system is very short, and the demonstrator can theoretically change temperature of the mixed water by around 5°Celsius per second. / Syftet med denna rapport är att utforska möjligheterna att spara både vatten och energi till duschar, genom en snabbare, mer responsiv och mer exakt duschblandare. Detta ska uppnås genom användning av digitala termometrar och stegmotorer. Duschblandaren ska läsa temperaturerna av det blandade vattnet, och justera respektive kran tills önskad temperatur är uppnådd. För att bibehålla önskad temperatur kommer temperaturen kontinuerligt övervakas. När störningar i temperatur uppkommer ska duschblandaren kompensera för det, och därmed hallå en konstant temperatur. För att åstadkomma detta byggdes en demonstrationsenhet. Denna demonstrationsenhet använder stegmotorer kopplade till kranar för att kontrollera flödet genom ett varmt och ett kallt vattenrör. Systemet läser konstant temperaturen av det blandade vattnet och gör lämpliga ändringar av kranarnas positioner. På grund av säkerhetsrisk användes inget vatten vid testning av demonstrationsenheten. Den teoretiska responstiden av systemet är mycket kort, och demonstrationsenheten kan teoretiskt ändra temperatur av det blandade vattnet med en hastighet av ungefär 5°Celsius per sekund.