Development of a model of transient heat transfer across walls and roof using conduction heat transfer functions (CHTF)

摘要

A transient heat transfer model was developed to predict heat flux across the walls and roof of residential a building. This method made use of constant coefficients, called transfer function coefficients, which depend on the material properties (such as density, conductivity, specific heat etc.) of the building. The coefficients account for the energy stored in the material. To capture this phenomena, the model depends on the value of previous heat fluxes and inside and outside air temperature to predict the heat flux at any present time. This approach makes the calculations more accurate and reliable. The validity of the model was tested by comparing estimated versus measured data. As it was expected, both results matched within a range of $pm$5 percent error for the days selected during the peak hours of the day. The ceiling frame was the side wall of the building that was modeled with more accuracy relative to the other four walls.;Ambient air temperature, hour of the day, room temperature, wall construction, orientation, and color or emissivity, were the inputs to the model. Heat fluxes were the output. Other parameter such as solar radiation, radiation with the surroundings, and convection were considered via sol-air temperature to make the calculations more accurate.