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Federal do Rio Grande
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EE - Escola de Engenharia

URI permanente desta comunidadehttps://rihomolog.furg.br/handle/1/512

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2011 - 20133

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Autor: search.filters.author.Vaz, JoaquimAssunto: search.filters.subject.FLUENT

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Experimental and numerical analysis of an earth-air heat exchanger
    (2011) Vaz, Joaquim; Sattler, Miguel Aloysio; Santos, Elizaldo Domingues dos; Isoldi, Liércio André
    The need to develop new technologies that allow the use of sustainable alternative sources of energy is increasingly evident. Thus, this work presents an experimental and numerical study of earth–air heat exchangers, which are used to reduce consumption of conventional energy for heating and cooling of built environments through the use of thermal energy contained in the soil. The experiment was conducted in southern Brazil in the city of Viamão, and its results were used to validate the computational modeling of heat exchangers. In the present work, the variation of air temperature inside the ducts, to an annual cycle, was investigated. The numerical solution of the conservation equations of the problem is performed with a commercial code (FLUENT) which is based on the Finite Volume Method (FVM). Turbulence is tackled with the Reynolds Stress Model (RSM). The transient temperature fields predicted numerically was compared with the experimental ones, the highest difference found was lower than 15%. The results showed the validity and effectiveness of the employed computational model, enabling its use for future researches and projects developments about earth–air heat exchangers.
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    Two-dimensional computational modeling of the soil thermal behavior due to the incidence of solar radiation
    (2013) Brum, Ruth da Silva; Isoldi, Liércio André; Santos, Elizaldo Domingues dos; Vaz, Joaquim; Rocha, Luiz Alberto Oliveira
    Nowadays, there is a focus on finding sustainable energy sources, as well as, alternatives to rationalize the use of electrical energy. In this sense, the employment of Earth-Air Heat Exchangers (EAHE) is one technique which allows the reduction of energy consumption for climatization of buildings environments. The present study shows the evaluation of a numerical method to estimate the ground thermal potential, allowing its applicability for future thermal design of EAHE. The soil domain is considered two-dimensional and a transient solution for the thermal behavior of the soil is obtained. Moreover, a soil surface temperature distribution equation based on experimental data is employed to define the domain boundary conditions. The simulations are performed with a numerical method based on the finite volume method, more precisely using the software FLUENT®. The results presented an excellent agreement with analytical solutions showing the validity and effectiveness of the computational model for prediction of the soil behavior. The numerical results were also confronted with experimental ones predicted into literature and show a good agreement, with a deviation lower than 14%. The main difference is attributed to the duct presence which is taken into account only for the experimental study.
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    A new computational modeling to predict the behavior of Earth-Air Heat Exchangers
    (2013) Brum, Ruth da Silva; Vaz, Joaquim; Rocha, Luiz Alberto Oliveira; Santos, Elizaldo Domingues dos; Isoldi, Liércio André
    The use of renewable energy sources to improve the thermal conditions of built environments and hencedecreasing the consumption of conventional energy is an important aspect to design a sustainable build-ing. Within this context, it is possible to harness the solar energy that reaches the Earth’s surface andis stored by the soil as thermal energy. To do so, the Earth-Air Heat Exchanger (EAHE) device can beemployed, consisting of a buried duct through which the external ambient air is insufflated. The flowingair exchanges heat with surround soil, and leaves the device with a milder temperature compared to itsinput temperature. The main goal of this work was to present a new computational modeling to predictthe thermal behavior of EAHE. This new numerical model has the advantage of needing a lower com-putational effort, allowing the study about the influence of operational and constructive parameters, aswell as, the application of geometric optimization methods in EAHE. A case study was developed whereinfluence of the installation depth in the thermal potential of an EAHE was investigated. The results arein agreement with those found in literature; however they were obtained with a reduction in processingtime of almost 45%.