Modelagem da transferência de calor combinada por condução e radiação em isolantes térmicos de edificações

AUTOR(ES)

Romulo Ruiz Gasparini

DATA DE PUBLICAÇÃO

2005

RESUMO

New insulation materials are being used in building industry to reduce electric energy consumption due to presence of HVAC (Heating, Ventilation and Air Conditioning) systems or to improve the thermal comfort of non-conditioned environments. An insulation material used in ceilings is the glass wool. The glass wool is considered as a semitransparent material, because the heat transfer process will occur by conduction and radiation. Thus, in this work, a numerical model to analyze the coupling of conduction heat transfer with the radiation heat transfer through the glass wool is developed. The numerical model considers unsteady one-dimensional heat transfer through the glass wool. in the one-dimensional space and transient state. The radiation heat transfer equation is solved by the Discrete Ordinates Method and the conduction heat transfer equation is solved by the finite volumes method with the TDMA (Tri-Diagonal Matrix Algorithm) technique. Two test cases are considered for two distinct days: first one, with high temperatures, representing a summer day; second one, with low temperatures, representing a winter day. The influence of radiative properties on the total heat transfer through the glass wool is evaluated. The accuracy and the simulation run time of the numerical model are analyzed to optimize the method. The numerical results are compared with other works and the heat transfer is compared for some materials used in building industry, showing the viability of using the glass wool in buildings.

ASSUNTO(S)

isolamento térmico engenharia mecanica calor - transmissão calor - radiação e absorção

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