Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
July 17, 2023
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Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
Partner: Rheem Manufacturing Co.
DOE Total Funding: $300,000
Cost Share: $300,000
Project Term: April 1, 2022 – September 30, 2023
Funding Type: CRADA
Project Objective
Considering the cost, efficiency factors of all the alternative refrigerants, it is clear that propane will be an optimum, long-term solution if meeting the safety regulation. This project aims to develop a propane HPWH achieving a UEF > 3.3 with a system charge of 150 grams. To achieve these goals, we will develop compact heat exchangers, including submerged condensers having double-wall tubes with external fins, or microtube bundles. Additionally, we will adopt microchannel or 5-mm fin-tube evaporator and propane optimized compressor. Special coating material will be developed and applied to reduce the water side scaling for long-term durability of submerged condensers. To achieve the goals while addressing the challenges, the proposed work aims to develop two HPWH prototypes, one using a submerged condenser with regular double-wall tubes (available on the market) and the other with micro-tubes (or channels) for a new development. ORNL will lead laboratory investigations, which include performance characterizations to measure uniform energy factors and first-hour rating, etc.; accelerated life tests will be carried out to investigate the water scaling behaviors. Rheem Manufacturing Co. will develop an innovative manufacturing process to fabricate and integrate submerged coils having double-wall tubes to a water tank in a cost-viable way. Rheem will also work with its supplier to adopt submerged micro-tube (channel) heat exchangers. The project team will work together to identify anti-scaling coating material for submerged condensers. The contractor will help the participant to develop heat exchanger sizing and HPWH system design tools using the new heat exchangers.
Project Impact
This project will replace high GWP refrigerants in Rheem's residential HPWH product lines. The utilization of very low-cost propane, priced at less than 10 cents for 150 grams, enables the creation of affordable heat pump water heaters. Additionally, the project aims to develop and calibrate a high-fidelity, public domain modeling and design tool for HPWH and heat exchangers using propane, accelerating the product development process.
Contacts
DOE Technology Manager: Payam Delgoshaei
Lead Performer: Mingkan Zhang