Airflow Based Model to Estimate Commercial Building HVAC Energy Use: Analysis to determine principal factors for different climate zones

The paper presents an airflow based modeling method to estimate HVAC energy consumption in large commercial office buildings. The model was developed by analyzing operational data from building automation system, relating load profiles and efficiency of key HVAC equipment,  based on economizer control policies that determine outside and return airflow rates. The model predicts annual energy use for buildings HVAC loads based on  hourly climate data (temperature and relative humidity), and building airflow requirements.  The model determines HVAC energy use in terms of building airflow rates for systems utilizing central air handler units with economizers, and identifies the key consumption drivers.  Some parts of the model (economizer performance and fan energy use) were based on data collected from the building automation system, relating major component energy use in terms of airflow rates and control laws. Data was obtained for three commercial scale office-lab buildings at Boston University.  Results are given in terms of major contributors to HVAC energy use and cost in terms of heating, cooling, and fan motor power for 4 different US cities.  A comparison to other building HVAC models used to disaggregate CBECs data is presented