Roadmap to Scaling: Best Practices from CO2 Heat Pump Water Heater System Pilots

The complexities of effectively implementing and operating system-level innovations makes pilots prone to failure, impeding their scalability. To increase the likelihood of pilot  success, we propose a paradigm shift toward an iterative and data-driven continuous  commissioning process. We applied this hands-on process to the startup of two multi-family central water heating systems with CO2 HPWHs. When our initial analyses revealed poor performance, we worked closely with the contractor  and manufacturer to diagnose the reasons, leading to controls and system piping modifications that significantly improved performance. We will share lessons learned for multifamily central HPWH systems and how to apply this approach to other complex building systems.