ET25SWE0062 - Central HPWH Retrofit Readiness Through Hot Water Distribution System Optimization Focused Pilot

Research question: How do inefficiencies in the HW distribution system create barriers to central heat pump water heater (CHPWH) installations? What can mitigate these inefficiencies in future installations and prepare commercial buildings for CHPWH retrofits?

Hypothesis: if a lack of aggregated guidance on commercial domestic hot water (DHW) distribution system optimization prevents contractors from optimizing DHW systems and installing central HPWH systems, then a field diagnostic procedure and a guide for optimizing systems should be developed alongside a recommended delivery model for trainings to make the knowledge readily available and improve contractor awareness. The pilot team expects this will result in greater commercial DHW system efficiencies that will lead to reduced energy consumption and increased adoption of CHPWH systems in existing buildings. 

Many incentive programs in California are targeting the decarbonization of water heating end uses with central heat pump water heaters (CHPWHs). While this is a much-needed effort, and multiple manufacturers are in the market, this technology can have disappointing results if the hot water distribution system hasn’t been optimized. Many CHPWH systems in multifamily and nonresidential buildings have optimization system issues such as oversized plumbing, poor pipe insulation and controls, unbalanced distribution systems, and poor maintenance, resulting in higher distribution system losses. This Focused Pilot topic focuses on developing a streamlined and standardized distribution system optimization approach for contractors and installers to ensure the successful design, installation, and operation of CHPWHs. The pilot is focused on preparing existing commercial buildings for CHPWH retrofits through optimization of DHW distribution systems.

The pilot aims to address the following barriers, laid out in the Technology Priority Map (TPM):

• Lack of familiarity with optimization measures
• Lack of aggregated guidance on central hot water distribution system optimization
• Risk-averse and business-as-usual mindset by contractors
• Lack of training within contractor community 

The pilot will address these barriers through the following activities:

• Conduct a market study to understand the common hot water distribution system inefficiencies
• Create a field diagnostic procedure for identifying distribution system issues
• Create a guide for optimizing distribution systems
• Develop recommended delivery model for trainings

The pilot aims to address the following primary research questions:

• What is the most feasible and highest impact market within the commercial sector that the pilot should focus on?
• What are the factors that create inefficiencies in CHPWH distribution systems of the highest impact market(s)?  
• What can contractors do to optimize inefficient CHPWH distribution systems?
• How can distribution system optimization strategies most effectively be disseminated to contractors?