Code Readiness Report: Energy Savings Analysis of Dedicated Outdoor Air HVAC in California Commercial Buildings

This research was performed to support the development and implementation of California’s Title 24, Part 6, Building Energy Efficiency Standards (“Title 24”), to better understand the potential energy and cost advantages of dedicated outdoor air systems (DOAS) and variable refrigerant flow systems (VRF) compared to mixed-air HVAC systems that are typically installed in commercial buildings in California. As part of this effort, the research team compared DOAS technology to traditional HVAC configurations, using a series of energy models, to evaluate system efficiency and operational cost. The research team utilized field-observed DOAS system configurations, HVAC system operational efficiency data, and measured annual energy use trends to develop a series of typical, hypothetical, DOAS HVAC configurations. The team then modeled the hypothetical DOAS configurations and traditional HVAC systems and analyzed the results to understand each system’s potential. The traditional systems evaluated include single zone CAV and VAV heat pump systems, and packaged VAV boiler or air to water heat pump systems. This report summarizes this analysis effort, outlines energy modeling results, and presents Title 24 enhancement recommendations.