Raley’s Supermarkets is a family owned chain that takes pride in its leadership and commitment to environmental sustainability. In addition to sustainability projects like reducing energy usage from lighting, the installation of solar panels, and generating natural gas from store waste, Raley’s is also leading the industry in its transition to non-ozone depleting, low global warming potential (GWP) refrigerants.
When Raley’s corporate engineering and energy groups considered the future of commercial refrigeration in light of new regulations and their own sustainability goals, they consulted with technical experts from long-time refrigerant producer Chemours (formerly DuPont Performance Chemicals) for the latest developments and low GWP options.
Overview of System and Conversion
The refrigeration system in Raley’s Santa Rosa store provides both low temperature (frozen food) and medium temperature (produce, meat, dairy) refrigeration, as well as air conditioning and hot water for the store. The system was originally designed to operate using R-404A refrigerant.
The Santa Rosa conversion project was completed overnight in October 2014 by PMC Mechanical, Inc., following retrofit guidelines provided by Chemours. Because the refrigeration system was already operating on POE oil, no lubricant change was required. Additionally, no change out of seals or gaskets was needed. After startup on XP40, the only major work required was to check and adjust the superheat on the individual TXVs, due to the lower mass flow rate of XP40 vs. R-404A. The existing valves were turned down to obtain the proper superheat and prevent liquid flood back. The system cases and walk-ins quickly pulled down to temperature and have operated reliably since the conversion.
Operational and Energy Performance
The table below provides operational data measured at similar ambient conditions for the system prior to, as well as at 1 week and 6 months, post-conversion to Opteon™ XP40. XP40 is shown to be operating as expected and consistently over this time frame.
Energy performance of the system has also been monitored since the conversion. Below is a plot of daily energy usage (KWH) vs. average daily temperature for selected days in the 16-20 °C (60-68 °F) range for R-404A as well as XP40. Reduced energy usage on the order of 8-9% is observed
After one year of operation, a sample of the refrigerant and lubricant were collected from the system and submitted for analysis. Laboratory results for both the POE oil and XP40 showed them to be clean and acid-free, with no indication of degradation.
Conclusion
The refrigeration system for the entire store at the Raley’s Supermarket in Santa Rosa, CA was successfully converted from R-404A refrigerant to low GWP HFObased Opteon™ XP40 (R-449A). The system has now been operating as expected for over one year with all parties pleased with the results. Raley’s has plans to convert other stores from R-404A to XP40 in the future; where other than making adjustments to the system controller set points and medium temperature TXVs, they plan on changing low temperature TXVs to fully optimize efficiency. “Year after year, we’ve been recognized nationally by the Environmental Protection Agency (EPA) GreenChill program as a sustainability innovator within the grocery industry,” said Randy Walthers, Raley’s Manager of Energy and Utilities, who captained the team that has improved energy efficiencies throughout the company. “Raley’s is proud of our continued focus on sustainability, and we have even more plans going forward. It’s about doing what’s right,” Randy added.
Find a study on how low-GWP formulations compare against carbon dioxide as a refrigerant HERE.
© 2016 The Chemours Company FC, LLC. Reprinted by permission.