A Numerical Investigation of Heat Transfer Coefficients for Indoor Window Insect Screens

Abstract

Due to rising energy prices as well as supply and ecological concerns, there is a strong interest in reducing the energy used in buildings. As such, it is desirable to model the operation of a building and predict its future energy use. In predicting the energy use of a building, the heat gain/loss through windows is an important factor. In order to accurately model this heat gain/loss, the convective heat transfer coefficient of any insect screens mounted adjacent to the windows needs to be known. This thesis describes an investigation into the heat transfer from insect screens mounted towards the indoor side of a window.

The convective heat transfer coefficient of an insect screen varies based on several parameters. For implementation in building energy modelling software, it is desirable to be able to predict the convective heat transfer coefficient for an arbitrary insect screen. Due to the number of variables and the large dynamic range of the details required for modelling, direct simulation of a range of whole insect screens was not completed. Instead, a range of numerical models representing small sections of an insect screen were created. By comparing results from these to available correlations for simpler geometries, such as cylinders and flat plates, estimates for the heat transfer coefficient of a screen can be obtained.

The results were non-dimensionalized for analysis and different methodologies for the prediction of heat transfer from an indoor window insect screen are described.