https://repositorio.ufu.br/handle/123456789/19223 Wed, 02 Sep 2026 04:32:01 GMT 2026-09-02T04:32:01Z https://repositorio.ufu.br/handle/123456789/49950 Title: Otimização do coeficiente de performance em sistemas de refrigeração utilizando o algoritmo simulated annealing assistido por redes neurais artificiais Abstract: The growing demand for energy efficiency in refrigeration systems, combined with the urgent need to replace synthetic refrigerants with lower-environmental-impact natural alternatives, drives the need to develop new optimization methods. Propane (R290), a hydrocarbon with a unitary global warming potential and excellent thermodynamic properties, represents a promising alternative to conventional refrigerants. However, its operation under maximumefficiency conditions requires tools capable of capturing and interpreting, even if approximately, the complexity and nonlinearity present in real refrigeration cycles. In this context, the present work proposes and validates an original hybrid methodology based on the Simulated Annealing metaheuristic algorithm assisted by Artificial Neural Networks to maximize the Coefficient of Performance in an experimental refrigeration bench operating with R290. The experimental data, comprising more than 12,000 records obtained under multiple operating conditions of the instrumented bench, cover suction and discharge pressures, temperatures at the four thermodynamic points of the cycle, and the opening percentage of the electronic expansion valve. The Coefficient of Performance for each operating point was rigorously calculated from enthalpy balances across the compression, condensation, and isenthalpic expansion processes, using precise thermodynamic properties of R290 obtained through the CoolProp library. These data were used to train a Multilayer Perceptron (MLP) neural network architecture capable of simultaneously mapping the input variables to four outputs — Coefficient of Performance, condensation temperature, evaporation temperature, and valve opening — achieving a mean squared error below 0.003 on the test set, which demonstrates the model's high predictive capability. The Simulated Annealing algorithm was then applied over the search space delimited by the real boundaries of the experimental data, using the trained neural network as a computational surrogate for the physical system. This eliminated the need for analytical models during optimization, drastically reducing computational cost without compromising fidelity to the nonlinear behavior, since the machine learning model implicitly incorporates the irreversibilities and nonlinearities of the real system. The results demonstrated that the proposed hybrid approach is capable of efficiently, robustly, and reproducibly identifying locally optimal operating conditions, establishing itself as a relevant contribution to the field of energy optimization in refrigeration systems. Mon, 03 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49950 2026-08-03T00:00:00Z https://repositorio.ufu.br/handle/123456789/49765 Title: Estudo de caso: Dimensionamento de uma rede de vapor Abstract: Este trabalho tem por finalidade dimensionar uma rede de vapor de uma indústria de tratamento de grãos de milho, de forma a basear-se em uma condição existente (cliente não revelado). Nessas indústrias é muito comum o uso da energia vinda do vapor para a realização de outros processos devido à facilidade de deslocamento de calor e energia até os pontos consumidores. Também, é comum o aproveitamento dessa energia a partir da instalação de unidades termelétricas para geração de energia. Neste caso, o vapor é originado por uma caldeira e, antes de ser transportado para os pontos consumidores, é levado para uma turbina. A turbina deixará esse vapor a uma pressão e temperatura menor do que a inicial, ocorrendo, assim, uma variação entálpica para geração dessa energia. No objetivo de aumentar ainda mais essa variação entálpica, este projeto tem o objetivo de diminuir a pressão e temperatura de saída dessa turbina. Para isso, foi feito o dimensionamento criterioso de perda de carga de modo a garantir que dois secadores (pontos consumidores) estejam com pressão disponível suficiente para operação. Ainda, foi feita uma pequena análise de flexibilidade da rede, uma vez que a alta temperatura do vapor na tubagem confere tensões devido a dilatação nos pontos fixados da rede. Mon, 01 Jan 2018 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49765 2018-01-01T00:00:00Z https://repositorio.ufu.br/handle/123456789/49756 Title: Detalhamento de planta de gaseificação em leito fluidizado circulante: montagem, integração dos sistemas da usina termoquímica experimental da UFU Abstract: The growing demand for technologies capable of promoting the energy recovery of waste has driven the development of gasification systems as a sustainable alternative for energy generation. In this context, the present study aimed to monitor and describe the implementation and commissioning of a pilot-scale circulating fluidized bed gasification plant designed for syngas production from Refuse-Derived Fuel (RDF). The adopted methodology consisted of monitoring the stages of mechanical assembly, hydraulic, electrical, and instrumentation installations, system integration, and commissioning tests. During the implementation phase, the reactor, cyclone, heat exchangers, gas cleaning system, hydraulic circuit, electrical infrastructure, automation system, and auxiliary equipment were installed, in addition to the interconnection of all process units. Cold commissioning tests were carried out to verify system tightness, equipment operation, control device parameterization, and the correction of nonconformities identified during the implementation process. The results demonstrated that proper assembly planning and effective commissioning were essential to ensure system integration, operational safety, and plant readiness for subsequent operational stages. This study contributes to the technical documentation of gasification plant implementation and highlights the importance of commissioning as an essential step in ensuring the operational reliability of thermochemical systems. Fri, 07 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49756 2026-08-07T00:00:00Z https://repositorio.ufu.br/handle/123456789/49725 Title: Dimensionamento hidráulico do sistema de proteção de incêndio por hidrantes e chuveiros automáticos do bloco 1JCG da Universidade Federal de Uberlândia Wed, 29 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49725 2026-07-29T00:00:00Z