The focus is on switching away from R-22 with alternatives that have been a part of the sector for years, including HFCs in retrofit applications and even more use of so-called natural refrigerants in new installs.
Revisiting HFCs
When the phaseout of CFCs began, an early wave of HFCs such as -404A and -507 were introduced. However, while many supermarkets did move to those refrigerants, the majority opted for R-22 because of its lower cost and ability to be used with mineral oil rather than the polyolesters (POEs) needed with HFCs. Now the latest rebuff of HCFCs is causing the HFC option to be revisited.
Polar Technology has begun issuing a series of reports on the topic of the R-22 shortage. On Feb. 13, the company posted a report titled “R-22 Shortage in Supermarkets.” The report focuses on larger size supermarket chains and how they can work their way through the supply issue.
Polar’s refrigeration focus was described as “How a 25-location supermarket can maintain both a cold environment and a reasonable budget in constrained R-22 material market.”
The report outlined three major issues regarding R-22. The first issue is the “massive reduction in R-22 availability due to EPA controls on imports and production.” Polar noted, “These controls are intended to reduce emissions in order that the United States meets our obligations under the Montreal Protocol.”
Second, the report commented that manufacturing is shifting from the United States to Asia. “As more materials are manufactured in Asia, the logistics constraints and inventory responsibilities have a major impact on availability, pricing, and terms.”
And third, Polar noted that new regulations are being developed to “track leaks, manage installations, and register climate control systems.” Additionally, the report noted the importance of knowing what refrigerant and how much an owner has, stating, “If you cannot measure it, you cannot manage it.”
Polar also revisited a longstanding guideline to owners of stores in multiple locations. The general guidelines encourage the owners to continue to use R-22 in well-maintained, tightly contained systems as long as possible. When such systems become obsolete, they should be replaced with HFC-based systems. In the retrofit process, the R-22 in the old system should be recovered and kept by the store chain owners to use at other stores where a retrofit from R-22 was currently not necessary. But before the R-22 is introduced elsewhere, purity to ARI-700 standards should be verified, even if that should require reclamation.
Going Natural
One of the most significant developments in terms of the use of non-f-gas refrigerants in supermarkets came during the March 2012 International Institute of Ammonia Refrigeration (IIAR) conference. The idea of using a toxic refrigerant outside industrial applications and in commercial places with high consumer traffic may have seemed unlikely in the past.
But the paper presented by Caleb Nelson of CTA Architects/Engineers at IIAR made a strong case for viability. Titled “Application of Ammonia in U.S. Supermarkets,” the paper admitted that “misconceptions of ammonia (R-717) and the codes that govern it, coupled with a lack of knowledge pertaining to the systems, serve as major hurdles that will need to be cleared before ammonia can be accepted as a viable alternative.”
Nelson acknowledged the difference between industrial refrigeration plants where ammonia is most commonly used and a commercial site like a supermarket relates to the amount of the refrigerant needed. “Less than a few hundred pounds of ammonia can typically be expected for a supermarket application,” he noted.
And unlike a typical supermarket where all mechanicals are within the store, use of ammonia will require a different approach. According to Nelson, “An ammonia system cannot be installed within a commercial space. Therefore, an outdoor rooftop ammonia chiller is the most feasible option. A packaged type of system with the refrigerant charge residing outdoors alleviates the potential for accidents involving employees and customers within the building.”
In the United States there is an added issue due to the classification of ammonia. “R-717 is now classed as a B2L refrigerant along with other mildly flammable refrigerants. Ammonia’s toxicity class remains unchanged but it is now recognized to be less flammable than a B2 refrigerant. This classification shift is still very new and has yet to materialize into any tangible changes in the codes pertaining to ammonia’s use. Therefore we must still treat ammonia like a B2 refrigerant,” Nelson noted.
He continued to explain, “This B2 classification is the foundation for which all codes and restrictions are applied to ammonia. In order to comply, one must employ an indirect, secondary (or cascade) system and limit the ammonia portion of the system to the outdoors or to a machinery room. An obvious example of such a system would be an ammonia chiller located on a rooftop, which would rely on a secondary fluid to chill the product. The ammonia is fully limited to the outdoors in this example; and as an added bonus, the ammonia charge is dramatically reduced.
“Supermarket owners that look to apply ammonia should be confident in the fact that a properly implemented system can be extremely safe and efficient. Beyond this, there are no deterring code restrictions preventing its use in the majority of the U.S. Designers should also be reassured by the fact that utilizing ammonia commercially doesn’t require the reinvention of the wheel. Although initial system cost and technician training are hurdles that are indeed real, it is comforting to know that they are only temporary and that they are no different from the hurdles that CO2 and other ‘new’ technologies are facing.”
CO2 in Supermarkets
Speaking of CO2 in supermarkets, a new report is providing a view of how use of the refrigerant in trans-critical systems is faring in Europe.
The marketing organization Shecco published “Guide 2012: Natural Refrigerants — Market Growth for Europe,” which showed 1,331 CO2 transcritical installations in Europe. Denmark has 424, the United Kingdom 267, Germany 166, and Switzerland 149, while France, Italy and Spain have fewer than 10 units each.
The Shecco report has been promoted as the first attempt to quantify the number of CO2 installations.
“While concerns regarding the efficiency of CO2 transcritical at higher ambient temperatures have impacted their uptake in southern Europe, the next generation of CO2 systems is expected to overcome these. Having overcome this major barrier, lessons from the four leading CO2 countries could then help pave the way for greater technology uptake,” the organization reported.
Publication date: 5/7/2012
