DECAT - Departamento de Controle e Automação
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/490
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Resultados da Pesquisa
Item Variables of influence on thermal performance of buildings under transient conditions.(2021) Ferreira, Camila Carvalho; Souza, Henor Artur de; Carlo, Joyce CorrenaResidential buildings significantly increase electricity demand, especially in developing countries. In this case, the requirements addressed by the standards can ensure the climatic adequacy of the envelope, enhance thermal performance, and promote thermal comfort conditions while reducing energy consumption. However, the criteria for evaluating the thermal performance of a building’s envelope that is commonly adopted in energy performance standards and codes have proved to be inefficient in hot climates. The heat exchanges within buildings are dependent on solar radiation and ventilation. The purpose of this article is to establish the variables with the greatest influence on the thermal performance of naturally ventilated dwellings in hot climates (equatorial, tropical and subtropical). For this investigation, a factorial design was adopted for sensitivity analysis. The structure of the factorial experiment defined the simulations of four patterns of single-family and multifamily residential buildings. We varied the thermophysical properties of the external walls and roofs, the heat gain coefficient of the openings, and natural ventilation. Brazil was adopted as a basis for climate analysis, including equatorial, tropical and subtropical climates. The analyses were based on comfort hours in an adaptive model and statistically evaluated using Analysis of Variance (ANOVA) tests. In general, the absorption of the walls and cover, the thermal transmittance of the cover and the natural ventilation were the variables of greatest influence on thermal comfort in a hot climate.Item An analysis of the economic viability and greenhouse gas emissions reductions resulting from the use of solar water heaters in a typical Brazilian dwelling.(2017) Altoé, Leandra; Oliveira Filho, Delly; Carlo, Joyce Correna; Monteiro, Paulo Marcos de Barros; Martins, Isabella Theresa de AlmeidaSeveral countries have reduced their energy consumption and greenhouse gas emissions levels in buildings by promulgating laws, formulating standards and instituting certification programs. In this context, Brazil launched an energy efficiency certification for buildings in 2009. This study aimed to analyze the economic viability and potential greenhouse gas emissions reductions associated with the use of solar water heaters in a typical Brazilian dwelling. Solar thermal systems were simulated at different energy efficiency levels and shower water flow rates. It was found that the use of solar water heater, as compared with electric heater without a hot water storage, presented internal return rate of approximately 26% per year, simple payback around 4.5 years; net present value about US$ 2,194.00 and cost of conserved energy around US$ 0.12 kWh-1. This study also verified that solar water heater use in a typical Brazilian dwelling reduced emissions compared with electric and gas heating by approximately 95 and 256 kgCO2equivalentyear-1, respectively. The total reduction potential of greenhouse gas emissions by use solar water heaters for the Brazilian residential sector was substantial, around 5.75 million tCO2equivalentyear-1.Item Computer programs for analysis of solar domestic hot water systems : RETScreen case study.(2015) Altoé, Leandra; Oliveira Filho, Delly; Martinez, Francisco Javier Rey; Carlo, Joyce Correna; Monteiro, Paulo Marcos de BarrosThe simulation programs are important tools for analyzing different energetic options, including the use of energy efficiency measures and renewable energies. The objective of this study was to analyze comparatively the different computer tools available for modeling of solar domestic hot water systems in buildings. Among the main simulation software in use for this purpose, there are RETScreen International, EnergyPlus, TRNSYS, SolDesigner, SolarPro, e T*SOL. Among the tools mentioned, only EnergyPlus and RETScreen International are free, but they allow obtaining interesting results. In the presented case study can be seen the versatility of the RETScreen program, which allows for analysis of energy production, economic viability and carbon dioxide emissions. Within the range of computer solar water heaters simulators currently available, it is necessary that the user knows the tool specifications, such as programming language and capabilities so one may choose the program that is most suitable to produce the expected results for one's knowledge and modeling skills.Item Computer tools applied to analysis of solar water heaters.(2013) Altoé, Leandra; Oliveira Filho, Delly; Carlo, Joyce Correna; Monteiro, Paulo Marcos de BarrosOs programas de simulação são importantes ferramentas para análise de diferentes alternativas energéticas, incluindo o uso de energias renováveis. O objetivo deste trabalho foi realizar uma análise comparativa das diferentes ferramentas computacionais disponíveis para modelagem de aquecedores solares de água. Entre os principais programas de simulação de sistemas solares térmicos estão: RETScreen International, EnergyPlus, TRNSYS, SolDesigner, SolarPro e T*SOL. Entre as ferramentas citadas, apenas o EnergyPlus e o RETScreen International são livres, mas permitem a obtenção de resultados interessantes quando aplicadas em conjunto. O primeiro possui um módulo de análise energética detalhado de aquecedores solares de água, enquanto o segundo possibilita um estudo detalhado de viabilidade econômica e uma avaliação de emissões de gases de efeito estufa. Os programas EnergyPlus e RETScreen International são destinados a um público-alvo diverso, incluindo projetistas, pesquisadores e planejadores energéticos.