Facing government scrutiny for having leaky, outdated cooling systems, retailers are wrestling with the mechanics of switching to newer, more environmentally friendly refrigerants.It's no small task for retailers, who are among the largest users of refrigeration systems in the world. Supermarket operators also are feeling some heat from the U.S. Environmental Protection Agency and the Department of

Facing government scrutiny for having leaky, outdated cooling systems, retailers are wrestling with the mechanics of switching to newer, more environmentally friendly refrigerants.

It's no small task for retailers, who are among the largest users of refrigeration systems in the world. Supermarket operators also are feeling some heat from the U.S. Environmental Protection Agency and the Department of Justice. Both agencies have been stepping up efforts to enforce provisions of the Clean Air Act of 1990.

In February 2005, Chicago-based Jewel-Osco Food Stores, a division of Albertsons, agreed to forestall penalties for non-compliance with the act by pledging to outfit more of its stores with refrigeration systems that use non-ozone-depleting refrigerants. The chain had been cited for allegedly violating the Clean Air Act's leak repair, testing, record-keeping and reporting requirements, which are aimed at controlling the release of chlorofluorocarbon (CFC) Freon and hydrochlorofluorocarbon (HCFC) R-22-type refrigerants.

Jewel-Osco did not return phone calls from SN seeking comment. However, as of December, Jewel-Osco had completed retrofitting refrigeration systems to use hydrofluorocarbon (HFC) refrigerants in 10 stores, and appears to be complying with the terms of the agreement to retrofit systems in 37 stores by 2007, said Sara Dauk, an environmental scientist in the EPA's Region 5 office.

The EPA has begun putting pressure on the supermarket industry to both address the growing issue of refrigerant leaks and begin phasing out systems that use refrigerants deemed environmentally hazardous. In the last year, the Food Marketing Institute opened a dialogue with the EPA regarding details on industry compliance.

The discussions have centered on the possibility of supermarkets accelerating the adoption of HFC R-404a-type refrigerants, which are more environmentally friendly, and moving away from CFCs and HCFCs, which will eventually be banned under international environmental treaties. Under such a scenario, the EPA would, in turn, agree not to bring any enforcement actions against retailers who fail to substantively address leaks of older refrigerants if they have an annual leak rate of 35% or less, the threshold laid out in the Clean Air Act.

Meanwhile, the EPA has been working closely with at least two retailers to jointly develop solutions that would presumably serve as a future model for the broader industry. The EPA declined to identify the chains by name.

While the two groups try to hammer out a workable approach, more supermarkets and suppliers of refrigeration systems are collaborating on possible solutions. From retrofitting existing systems to use new refrigerants, to improving leak detection and repair procedures, to redesigning systems to have shorter refrigerant line runs, the search is on for workable, but affordable fixes.

One component of a long-term solution is moving to adapt existing systems to use the HFC class of refrigerants, such as R-404a and R-507. Refrigeration system vendors such as Copeland Refrigeration, Sidney, Ohio, a leading supplier of compressor components to supermarkets, has been advising supermarkets on retrofits.

"Those with racks that use R-22 [an HCFC refrigerant that will become increasingly expensive as a 2010 production phaseout nears] are encountering some costly challenges in converting," said Warren Beeton, Copeland's vice president of refrigeration. "One is the need to drain old systems of mineral oil, which is the lubricant used in many R-22 systems, because it doesn't work well with newer lubricants designed for HFCs. That can mean going through several cycles of flushing and restarting."

Such costs may be keeping many supermarkets on the sidelines. Changeovers can involve installing new control valves and time-consuming sequenced flushing of oil from multiple rack systems, according to a service manager with ABC Refrigeration, a company that services many stores in and around its home base in Syracuse, N.Y.

"It's very expensive, and I'm guessing that's why most supermarkets are not doing it," said Adam Purtell, the service manager. "Some of the stores that are part of big chains in the Syracuse area are converting to R-404a, but there are still a lot of R-22 stores out there."

Another equally expensive option for supermarkets is addressing refrigerant system leaks. More supermarkets are stepping up their leak detection and repair capabilities in an effort to curtail the release of CFCs or HCFCs. That can involve the installation of more elaborate alarm and leak isolation systems, as well as the initiation of costly repairs to the maze of lines that carry refrigerant to display cases.

Other approaches to leak reduction involve equipment manufacturers making equipment that's more leak-proof, and installing entirely new types of refrigeration systems that either shorten the lines carrying refrigerant or reduce the circulation of refrigerants in the lines.

"One of the industry's approaches is to make HFC systems that don't leak, allowing conventional rack systems that are cost-effective and efficient to remain viable," said Doug Bishop, director of marketing for Carrier Corp.'s Niles, Mich.-based Tyler Refrigeration division, a leading supplier of supermarket refrigeration systems.

For supermarkets with deeper pockets, the ultimate solution may be to install radically redesigned systems that accommodate safer HFCs.

One emerging possibility is installing secondary loop systems that segregate refrigerant-containing equipment to a separate, centralized location, allowing the use of fluids like propylene glycol to transfer heat from the food display cases.

"Rather than running refrigerant out to cases on copper lines, you run glycol, eliminating the danger of leaking chemicals that are harmful to the environment," Beeton explained.

One of the barriers to using glycol, however, is that it doesn't work nearly as well in low-temperature applications as it does in medium-temperature environments, Bishop said.

Another, similar approach called distributed refrigeration puts refrigeration equipment closer to display cases. That serves to minimize refrigerant piping needed to connect to a mechanical room. The less piping there is, the less chance for leaks.

"More smaller, discrete systems rather than one big system that have shorter line runs have a lower refrigerant charge, so if they leak the release is not as great," Bishop said. "But the downside is that as you go from central to distributed compressors your efficiency goes down."

Looking ahead, supermarkets will have to move toward systems that use alternate refrigerants - most likely HFCs - and also do a better job of addressing leaks. As production of both CFCs and HCFCs are phased out, the costs of securing those refrigerants will rise, even though existing systems that have been sufficiently leak-proofed may still be able to use them.

But the issue may not even be resolved with the emergence of HFCs. Though not considered ozone-depleting like CFCs or HCFCs, HFCs are suspected of being a greenhouse gas that contributes to global warming.

Under an international global warming treaty, the Kyoto Protocol, participating countries would commit to reducing the use of greenhouse gases like HFCs. While agreeing to the Kyoto Protocol in principle, the United States took issue with some specifics, and has not signed the treaty.

New Options

It's a speck on the horizon now, but carbon dioxide is emerging as a viable alternative to traditional refrigerants used by supermarkets abroad.

In Europe, a growing number of supermarkets are either installing or considering systems based on CO2 rather than chlorofluorocarbon (CFC) Freon, hydrochlorofluorocarbon (HCFC) R-22 and even safer hydrofluorocarbon (HFC) refrigerant R-404a.

According to company literature, Danfoss A/S, a United Kingdom-based firm, is putting more of its ADAP-KOOL refrigeration control systems into supermarket systems that use CO2. The company's biggest market includes countries in the European Union, which are discussing a phaseout of HFCs because of their suspected contribution to global warming.

American suppliers of refrigeration systems are watching progress with carbon dioxide systems. Though most of the interest and application of such systems is in overseas markets, some companies said it has potential for success in the U.S. market. A European subsidiary of Carrier Corp., Linde Refrigeration, has participated in the installation of 65 carbon dioxide-based systems in Europe, said Doug Bishop, marketing director for Tyler Refrigeration.

Carbon dioxide systems present both opportunities and challenges, he said.

"It's naturally occurring, benign and a good heat transfer medium, but barriers to its widespread use include pressure requirements and control algorithms that are different and unique, and the need for different types of valve solutions," Bishop said. "The supply chain in North America for system components is not yet CO2-ready.

But if concerns over global warming and ozone depletion heat up, supermarkets and other large users of refrigeration may be forced to look more seriously at CO2 and other alternatives.