A procedure for automating thermal zoning for building energy simulation

Although many previous studies have addressed the accuracy of building energy simulations, very few studies of this subject have mentioned the importance of Heating, Ventilation, and Air-Conditioning (HVAC) thermal zoning strategies to sustainable building design. In addition, the building energy standards and guidelines related to building energy simulation recommend that only a core and perimeter thermal zoning strategy be used to reduce the total number of thermal zones in a model. However, although this simplifies modeling, it can lead to too many thermal zones in the building energy model of a multi-story building, or in some cases too few zones, which can impact the model's accuracy. Therefore, the aim of this study is to develop a new thermal zoning process for building energy simulation called the "grid/cluster method." that can be applied automatically to whole-building energy simulations of multi-zone commercial structures. To verify this new thermal zoning method, the indoor temperature profiles of grid units were carefully analyzed in a case study simulation. In this study, three thermal zoning simulation models for a rectangular building were created and applied in heating- and cooling-dominant climates. The results show that for both climate conditions, the new grid/cluster method reduced heating/cooling loads by 11%-27% as compared to the single-zone model. In addition, the results significantly improved the simulated indoor comfort conditions.