The U.S. Defense Commissary Agency (DeCA) is looking to increase its adoption of CO2 refrigeration systems after the successful installation of a cascade system at a store in San Antonio, Texas. The use of CO2 refrigeration systems is being widely adopted by European supermarkets and is now gaining in popularity in the U.S. DeCA is an agency of the U.S. Department of Defense that operates more than 245 commissaries worldwide, selling groceries and household goods to US servicemen and their families.
The 117,000ft² commissary in San Antonio, Texas, supplying Lackland Air Force Base recently converted its R404A system to an ammonia/CO2 cascade system. The previous refrigeration system, which contained around 3,200kg of R404A was over 13 years old and was ready for retirement. DeCA replaced the old refrigeration system with help from Hillphoenix and CTA Architect Engineers.
Although initial costs of the NH3/CO2 cascade system were roughly 15% higher than a standard system—an incremental cost of roughly $334,000—operational savings from energy use, refrigerant use, and maintenance costs are expected to greatly offset these costs, likely resulting in only a small overall cost increase over the estimated 20-year lifetime of the system.
DeCA says that the greatest challenge it faced in the installation was public acceptance of using ammonia in a building near sensitive areas, such as day care facilities and schools. To address this concern, the National Renewable Energy Lab and the Environmental Protection Agency — with technical assistance from CTA Architects Engineers and Hillphoenix — conducted an ammonia plume study, which analyzed the potential effects of ammonia being released from the system into the community. Results of the study showed that the system poses minimal threat to human health, with impacts mainly limited to short-lived unpleasant odours and risks could be mitigated through the use of a leak monitoring system.
DeCA now anticipates adopting NH3/CO2 cascade systems as the standard technology at other commissaries located in warm climates, as well as being considered for installation in other types of facilities such as DeCA’s cold storage and central distribution centre at Sagami General Depot in Japan.
JIM ARMER, DIRECTOR OF ENERGY SERVICES:
“CTA continues to experience interest in alternative refrigeration system adoption and application. As equipment approaches replacement age (as with the DeCA facility) and new facilities are constructed, owners have the opportunity to strategically evaluate meeting energy and environmental goals and requirements. With the likelihood of an increase in these requirements, CTA has become well-versed in evaluating and supplying options in the rapidly changing industry.”
CALEB NELSON, REFRIGERATION SERVICE SECTOR LEADER:
“We’re seeing many end users looking to scrap their traditional systems and really challenging themselves to find the best way to move forward. Everyone wants to better their position in the market moving forward and having a refrigeration system that is efficient and ‘future-proof’ has become a big part of that.”