Mexican supermarket chain Casa Ley has reported a 3.7-year payback period on a transcritical CO2 (R744) refrigeration system installed at its 7,000m2 (75,347ft2) new-build store in Caliacán, in the state of Sinaloa, in 2018.
According to Rafael Francisco Navarro Torua, Senior Manager of Maintenance and Hygiene at Casa Ley, the system has delivered annual efficiency savings of 8–10% compared to a conventional R404 system, with energy consumption depending on ambient temperatures each year.
This installation was Casa Ley’s first transcritical CO2 store, designed to help the retailer familiarize itself with the technology as it works to phase out its use of R22 by 2030, he explained. It was also important to prove that CO2 refrigeration could be a safe, efficient, and financially viable investment in Mexico’s climate.
“After six years of operating our rack, we can say that it is a very stable rack,” Navarro Torua explained.
The transcritical CO2 refrigeration system meets the supermarket’s low- and medium-temperature cooling demands, providing 23kW (6.5TR) for frozen food storage and 129kW (36.7TR) for refrigerated display cases. It operates with saturated suction temperatures of −28.9°C (−20°F) for low-temperature (LT) applications and −6.7°C (20°F) for medium-temperature (MT) applications.
The system comprises a parallel rack and refrigerated display cases from U.S.-based manufacturer Kysor Warren, an adiabatic gas cooler from Güntner, compressors from Bitzer and controllers from Danfoss.
Navarro Torua shared Casa Ley’s experience during an end user panel discussion at the ATMO LATAM Summit 2025. The conference was hosted by ATMOsphere, publisher of NaturalRefrigerants.com, and took place February 19–20 in Mexico City.
Having proven that transcritical CO2 is safe and efficient in the Mexican climate, Casa Ley is looking into upgrading the system at the Caliacán supermarket and developing a new CO2 store project. It is also planning to begin tests with other natural refrigerants like propane (R290).
Technical challenges
Despite a positive overall experience with transcritical CO2 refrigeration, Casa Ley has faced some technical challenges over the system’s six years of operation.
Key issues included system slowness, defrost inefficiencies, oil-return complications and controller communication failures. However, most were minor and quickly resolved with manufacturer support. Solutions included installing repeaters to improve system speed, training technicians on sensor diagnostics and fine-tuning set points and control algorithms for better performance.
The system has experienced only two major failures, one due to human error during maintenance and the other during an extreme heatwave, when temperatures peaked at 49°C (120°F).
“We have had some problems, but after talking to the rest of the stores that we have in our company about performance and the consumption of spare parts, these have been very small,” he explained.
Lessons learned
Prior to the installation of the transcritical CO2 system, Casa Ley anticipated some challenges, namely the availability of high-pressure components, CO2 refrigerant and service technicians.
To address this, the retailer partnered with equipment suppliers to train its staff, ensuring they could manage and optimize the system. Over the past six years, this hands-on experience has expanded their expertise in CO2 technology, preparing them for future projects.
“I cannot say that we know everything or that we do things perfectly,” said Navarro Torua. “I think that we will continue learning, and now can look into expanding our use of this type of cooling.”
Casa Ley has also stocked up on R744 refrigerant and key spare parts, including one LT and one MT compressor, to minimize system downtime in case of an emergency.
“Previously, Guadalajara was the closest place where we could get CO2 from,” he said. Guadalajara is roughly 430mi (692km) from Caliacán.
