Impact of thermal zone modeling on a small office building with all-electric HVAC systems in hot-humid and cold-humid climates

In code-compliant simulations, the impact of thermal zoning method is significant on building energy use of building systems. However, in practice, thermal zone modeling is often determined by general rules without careful consideration of the specific characteristics of different HVAC systems. Therefore, this study evaluated the impact of thermal zone modeling on all-electric HVAC Systems in hot-humid and cold-humid climates using different levels of usage profiles. The results of this study identify the significant influence of thermal zoning methods on the annual energy use in all-electric HVAC systems depending on usage rates and climate. When different thermal zoning models were used, the amount of energy used differed depending on HVAC system type and zone usage (i.e., PSZ system varied from 4.6% to 8.8% in Houston, TX, and from 4.6% to 20.1% in Chicago, IL). In addition, a significant difference can be found in peak heating demands for selected HVAC systems in buildings located in cold climates (i.e., for winter peak days, the daily load differences of 21.8% to 24.5% in Chicago, IL). The results of this study can be used to improve the accuracy of thermal zone modeling for code compliance that considers different HVAC system types.