Code Readiness Case Study: Heat Recovery Dedicated Outdoor Air System with Heat Recovery VRF Retrofit: Office Building in Martinez, CA

The Martinez Case Study is one of eight buildings evaluated under a Code Readiness field monitoring research effort to better understand real-world performance of dedicated outdoor air systems (DOAS) in California. The Martinez site was renovated in 2019 with a fully decoupled HVAC system using a DOAS unit with a heat recovery ventilator (HRV) and a multi-zone VRF system with heat recovery for space heating and cooling. This case study describes the sites HVAC configuration attributes and shares energy efficiency findings including heat recovery effectiveness and heating/cooling distribution efficiency in a retrofit application. This case study also identifies Title 24, Part 6 code and market mechanisms to support adoption of high-efficiency DOAS and VRF systems.

In contrast to mixed air systems, DOAS HVAC configurations achieve efficiency by independently optimizing the ventilation and/or conditioning system. Prior studies from other parts of the US indicate that using a dedicated ventilation system that heats, cools, and dehumidifies outdoor ventilation air can significantly reduce annual energy consumption, and both winter and summer peak loads. However, few studies have assessed the performance of DOAS systems in California’s unique climate or evaluated variation in performance for different DOAS system attributes, technologies, and strategies.