| The scope of this study is to develop a user-friendly software to evaluate building hourly loads. The following physical phenomena are taken into account: transient thermal conduction through opaque walls, convection and long wave radiation interchange at the internal and external surfaces, solar heat gains on external surfaces, solar heat gains through the windows and internal gains due to indoor thermal sources.; The present model assumes that any building can be modeled by four peripheral zones and an internal zone. The different thermal processes mentioned above occur in each of these five zones.; The Fourier transient conduction equation is solved by finite difference using an implicit scheme, according to the method proposed by Patankar. Each wall layer has three grid points. Since wall can contain up to five layers, calculations will be performed for a total of fifteen grid points.; Solar heat gains through the windows use the Solar Heat Gain Coefficient (SHGC) approach proposed by ASHRAE. The internal gains in each zone come from the occupancy, the lighting and equipments. The convective portion of these gains contributes immediately to the zone load while the radiative portion is absorbed by the internal surfaces and released later. These internal gains follow an established profile according to building occupation.; The long wave radiation exchange uses an approximate view factor calculation which can handle any building shape with good accuracy. The thermal losses through the windows are calculated with the overall heat transfer coefficient U.; The software developed here, which is called B5EES, is validated with an ASHRAE analytical validation tool. The results of this validation, performed for five different tests, show that B5EES gives good results. The validation with BESTEST also reveals good results for the four possible simulated tests. |
