Gas-Fired Heat Pump Water Heating - Phase 2F – Site #1 Enhancement

This project is a field study of a Gas Absorption Heat Pump (GAHP) water heater. The GAHP is a gas-fired technology with a technology readiness level (TRL) of 9. This project falls into phase 2F (field study phase) of a multi-phase field study pilot project for GAHP water heaters & combination systems. Phase 1 of this pilot was completed to address the initial planning and data gathering necessary for phase 2F to launch. Phase 2F plans to have installations in four (4) sites total, but the other three (3) sites are not part of this scope. For reference, Phase 2F Site #2 is currently underway and Phase 2F Site #1 is expected to wrap up by Q1 2025. This project is an extension of Site #1 in phase 2F. Site #1 was the first GAHP installation in a domestic hot water only (DHW-only) application and had many challenges that were discussed in the preliminary report. The GAHP is saving a minimal amount of energy right now because the average GAHP run time is less than 20 minutes. The Study Team has decided to launch an extension project to make changes to the existing GAHP + DHW Boiler systems to maximize the run time of the GAHP. Those changes include: • Inclusion of recirculation load in load served by GAHP • One of the following: o Installation of (2) indirect storage tanks (ISTs) to replace the plate and frame heat exchangers o Installation of (2) additional traditional storage tanks (STs) and replacement of existing heat exchangers with new heat exchangers. New STs will operate with new heat exchangers to act as a thermal battery • Modification of GAHP controls and potential addition of controls Additionally, the analysis scope is increased to include a comparison of the field results to the lab results from ET23SWG0015.