Modelling of basement heat transfer in EnergyPlus simulation program

Abstract Soil temperature is one of the most influential factors in the evaluation of the thermal performance of underground environments, but it is almost always disregarded. Thus, it is necessary to evaluate this influence due to the interaction of the soil with the building, since heat transfer through subterranean walls and floors has a significant extension in the total thermal load of a building. This study compares and evaluates the impact of different modelling alternatives present in the EnergyPlus simulation program by analysing the heat exchanges between the soil, the floor and the walls of a basement of a single-story building in São Paulo, Brazil, not artificially conditioned and not insulated thermally. The comparison between the modelling alternatives through the analysis recommended by NBR 15575 indicated a large variation in the internal temperature results of the underground building environment. When compared with Basement pre-processor, the models of the object GroundDomain presented an internal temperature variation of the basement up to 6 ºC in the summer and up to 5.2 ºC in the winter. These results offer indications of the influence and variability that the use of the different modelling options present in EnergyPlus program can generate in a thermal performance analysis.