DECAT - Departamento de Controle e Automação
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/490
Navegar
8 resultados
Resultados da Pesquisa
Item Naturally ventilated industrial sheds : an investigation about the influence of wind direction in flow rate efficiency in continuous roof vents.(2021) Camargos, Bruno Henrique Lourenço; Souza, Henor Artur de; Gomes, Adriano Pinto; Ladeira, Artur Hallack; Reis, Reinaldo Antonio dos; Mapa, Lidianne de Paula PintoNatural ventilation portrays an effective technique for lowering the internal temperature, without spending electricity, and directly contributes to the renewal of indoor air by establishing a healthy environment for workers. Given this, it is usual to have air vent openings located at the top of the roof (continuous roof vents), in addition to those present on the facades of sheds. In naturally ventilated buildings, it is recommended to give due importance to the provision of these openings, since depending on the proposed arrangement, the wind may or may not help in the effectiveness of this strategy. In this work, it is evaluated via computer simulation (EnergyPlus, version 8.7.0), for the climatic conditions of the city of Belo Horizonte/Brazil, the influence of the wind direction in the flow rate of indoor air through the ridge vents, of the longitudinal and transversal type, present in industrial sheds endowed with an internal source of high-intensity heat release. The results obtained show that the flow rate has a symmetrical behavior in the openings of the longitudinal continuous roof vent, that is, when an opening is with the maximum outflow of the internal air, the opening opposite the predominant wind direction is acting as an entry point for the air external. The transverse continuous roof vents are more sensitive about the wind direction since they are positioned perpendicular to the building. The best result found is for the wind situation occurring parallel to the shed, obtaining a reduction in the internal temperature of up to 1°C, an increase in the rate of air changes per hour, in the internal environment, at 1acph, and an increase of up to 10,7% in the volume of air infiltrated into the shed.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 Influência de paredes verdes no desempenho térmico de habitações sociais.(2020) Sousa, Luana Resende de; Souza, Henor Artur de; Gomes, Adriano PintoA utilização da vegetação como elemento de fachada ainda compreende uma prática bastante incipiente, mas tem se popularizado devido à promessa de melhoria no desempenho térmico das edificações, além de representar uma alternativa de ampliação da biodiversidade no ambiente urbano. Neste trabalho investiga-se a influência das paredes verdes, no contexto climático brasileiro, sobre o desempenho térmico de edifícios habitacionais de interesse social. Como metodologia, utiliza-se a simulação do comportamento termoenergético de um edifício habitacional multifamiliar, por meio do programa EnergyPlus, incluindo-se o modelo HAMT que leva em conta o processo de transferência de umidade através da envoltória, para três zonas bioclimáticas previstas na norma NBR 15.220-2005, clima extremo para inverno (ZB1), clima extremo de verão (ZB8) e para um clima considerado como intermediário (ZB3). Os resultados obtidos demonstram uma diferença na temperatura interna dos ambientes, decorrente dos dois arranjos de fachada analisados: com e sem vegetação. O uso da parede verde proporcionou uma redução na temperatura interna de até 2,8 °C no verão e um aumento de até 1,4 °C no inverno. Observa-se que a vegetação na fachada ajudou a manter a temperatura interna mais baixa durante o dia e amena durante a noite. Logo, as paredes verdes podem representar uma solução sustentável e de baixo custo a ser implantada às edificações, visando melhorar seu desempenho térmico.Item Computer simulation of moisture transfer in walls : impacts on the thermal performance of buildings.(2021) Araújo, Mariana Tonini de; Souza, Henor Artur de; Gomes, Adriano PintoIn order to reduce electricity consumption in buildings, it is imperative to improve their thermal performance. Due to the many variables involved in thermal processes computer simulation is a consolidated method for thermal analysis. However, in many energy efficiency analyses calculus of heat conduction through the dwelling envelope does not consider moisture transportation and storage. The objective of this work was to evaluate the impacts of moisture transfer in walls on the thermal performance of naturally ventilated and artificially conditioned buildings using EnergyPlus computer simulation. This research contributed to the literature by showing the difference in thermal zone air humidity, temperature and annual energy demand (i.e. electricity consumption) when moisture effects are considered in walls. Buildings were composed of masonry and solid concrete envelopes and three numerical models were simulated: Conduction Transfer Function Model (CTF), Effective Moisture Penetration Depth Model (EMPD) and Combined Heat and Moisture Transfer Model (HAMT). The CTF model does not consider moisture effects. Results found a higher relative air humidity for the studied thermal zone by applying the HAMT model in the numerical simulation, and the envelope porosity was proven to affect HAMT humidity results. Comparing the HAMT and EMPD models with the CTF model, the annual energy demanded for cooling presented a 21% reduction for the EMPD model in the masonry and 9% increase for the HAMT model in the solid concrete. This article shows the importance of an accurate EnergyPlus heat transfer model for simulating a whole building to check edification attendance of minimum comfort parameters and select envelope materials aiming the reduction of electricity consumption.Item Evaluation of the thermal performance in external vertical enclosures constituted of metal panels.(2021) Faria, Marcela Assunção; Souza, Henor Artur de; Ferreira, Franciele Maria CostaBrazil has a great climatic diversity, with different demands for the adequate thermal performance of buildings, where the variables that impact it have different influences depending on the location and the type of wrapping used. When a prior study of the thermal performance of a building is not done in the design phase, the unpleasant effects for the user appear after the building is ready, and bring with them problems such as internal temperatures that are too high in the summer or too low in the winter. Therefore, the objective of this study is to provide recommendations for the application of ACM (aluminum composite material) composite panels and thermoacoustic (sandwich) tiles for external enclosure in the single-family residential sector. A high standard two-story residence with approximately 162 m2 per floor is used as a model and through computer simulations, utilizing the Energyplus program and observing the requirements of the NBR 15.575 performance standard, the thermal performance is evaluated. The factorial experiment was applied encompassing thermal performance variables such as absorptance, natural ventilation and thermophysical properties of the “wrapping for three different climatic conditions: extreme winter climate, average climate and extreme summer climate. The results obtained show that the thermoacoustic roof tile keeps the internal temperature more stable independent of external oscillations, while the ACM panels follow the external oscillations, not meeting the expectations of thermal performance and needing passive treatments.Item Effect of the exposed steel structure on the thermal performance of buildings.(2022) Caetano, Lucas Fonseca; Souza, Henor Artur de; Gomes, Adriano PintoDepending on the building typology, the architectural characteristics and the materials used in a building, its interaction with the local climate can produce negative impacts on the energy consumption of the buildings. The presence of steel in the building structure characterizes a reduction in the thermal resistance of the building envelope, which causes an increase in energy costs for environment heating or cooling. In this context, simulation of the thermal performance of buildings using computer programs has generated several constructive advantages for the establishment of energy-efficient buildings. This paper’s main purpose is to evaluate the influence of the exposed steel structure area on the thermal performance of naturally ventilated and artificially conditioned environments using computational simulations. The results showed that in the numerical simulation of naturally ventilated environments, there were increases of about 3.0% and 2.0% in the environment indoor temperatures during the winter and summer periods, respectively. Considering the winter period, the heat losses through the steel structure were up to 4.1 times larger concerning those made for walls without steel, and the heat gains about 4.2 times higher in the summer period. The effects of thermal bridging were more evident in the evaluation of artificially conditioned environments. There was a maximum increase of 4.8% in the environment total cooling thermal load and, as a consequence, a maximum variation of 4.9% in the building energy consumption, evidencing that the larger the exposed steel area in the building closure system, the larger the effect caused by this thermal bridge.Item Impact of thermal bridging on the performance of buildings using Light Steel Framing in Brazil.(2013) Gomes, Adriano Pinto; Souza, Henor Artur de; Tribess, ArlindoThe Light Steel Framing building technology was introduced in Brazil in the late 1990s for the construction of residential houses. Because the design systemwas imported from the United States and is optimised to work well in that temperate climate, some modifications must be made to adapt it for the Brazilian climate. The objective of this paper was to assess the impact of thermal bridging across enclosure elements on the thermal performance of buildings designed with Light Steel Framing in Brazil. The numerical simulation program EnergyPlus and a specific method that considered the effects of metallic structures in the hourly simulations were used for the analysis. Two air-conditioned commercial buildings were used as case studies. The peak thermal load increased approximately 10% when an interior metal frame was included in the numerical simulations compared to non-metallic structures. Even when a metal frame panel was used only for vertical elements in the facade of a building with a conventional concrete structure, the simulations showed a 5% increase in annual energy use.Item Influência da inércia térmica do solo e da ventilação natural no desempenho térmico : um estudo de caso de um projeto residencial em light steel framing.(2011) Souza, Henor Artur de; Amparo, Lucas Roquete; Gomes, Adriano PintoThe light steel framing technology requires some design adaptations in order to have an adequte thermal performance in Brazil, since it was imported from the USA, In this study, the thermal performance of a light steel frame single-family house, in Belo Horizonte, state of Minas Gerais, was evaluated considering some natural ventilation strategies and the influence of soil inertia. To determine the model’s thermal behaviour, the EnergyPlus simulation program was used. The following stages were carried out: characterization of the structure, its typical exposure to the weather; occupants’ profile and their demands; configuration of closing system; and the evaluation of the building’s thermal comfort conditions and to what extent they meet existing standards. The conclusion was made that a suitably ventilation system could significantly improve the building’s thermal performance, if the local climatic conditions are duly taken into account. Likewise, depending on the land plot topography and the design characteristics, the influence of the soil thermal inertia, when associated to suitable ventilation and shading strategies, could be helpful to improve the design thermal performance.