IIAR

by Eric Smith, P.E., LEED AP, IIAR Technical Director

Recently, the IIAR participated in the presentation of a webinar in association with the EPA’s GreenChill Partnership. The focus of the webinar was to examine the use of ammonia in combination with CO2 for use in supermarket refrigeration systems. Ammonia’s low Global Warming Potential (GWP=0) and low Ozone Depletion Potential (ODP=0) along with the similar characteristics of CO2 make them an attractive alternatives to synthetic refrigerants. As described below, interest in the application of these systems in the United States is building. Discussion in the Webinar surrounded potential energy savings, construction of the systems, and potential hurdles that must be overcome for this application of natural refrigerants to gain acceptance.

EPA’s GreenChill Partnership

GreenChill is an EPA Partnership Program with supermarkets to reduce refrigerant emissions and decrease their impact on the ozone layer and climate change. GreenChill was founded in November 2007 with just six supermarket partners. To date, forty supermarket companies with close to 5,500 stores nationwide have become GreenChill partners.

The goals of the GreenChill Partnership are to provide the supermarket industry with information and assistance to lower refrigerant charge sizes and eliminate refrigerant leaks; transition to environmentally friendlier refrigerants; and adopt green refrigeration technologies, strategies, and practices.

GreenChill has three main programs to achieve those goals: the Corporate Emissions Reduction Program, the Store Certification program, and the Advanced Refrigeration Program.

The GreenChill Corporate Emissions Reduction Program

GreenChill partners make a commitment to EPA that they will measure their corporate-wide aggregate refrigerant emissions annually and set an emissions reduction goal for each year. A Partner’s first emissions report is the company’s baseline year. EPA then measures the partner’s progress in reducing emissions vs. that baseline year and the progress from year-to-year.

In 2009, the latest reporting year, GreenChill partners had an average corporate refrigerant emissions rate of 12%, which is much lower than EPA’s estimated industry average annual emissions rate of 25%. If every supermarket in the nation had an emissions rate equal to the GreenChill average, they could prevent the annual emissions equal to about 22,000,000 metric tons of carbon dioxide. Reducing refrigerant leaks is not just good for the environment. It is good for supermarkets’ bottom lines. The industry would also save over $100,000,000 on refrigerant used to replace leaks.

The GreenChill Store Certification Program

Reducing refrigerant emissions corporatewide requires a lot of hard work on an individual store level. There are several certification programs that offer incentives for food retail stores to increase their energy efficiency and tackle other environmental goals; however in 2008, when GreenChill launched its store certification program, there weren’t any other programs that provided recognition to companies that committed to and invested in commercial systems that lowered refrigerant charge size and leak rates With refrigerant emissions accounting for 20-30% of a supermarket’s carbon footprint, there was a need to encourage these types of investments.

GreenChill has three certification levels available: platinum, gold, and silver. There are only two stores in the nation that have achieved GreenChill platinum, the Price Chopper Colonie store in New York and the Chestnut Hill Star Market in the Boston area. Both of these stores achieved impressive emissions reduction vs. a typical supermarket with a centralized direct expansion system. Both stores will emit less than 25 pounds of refrigerant annually, vs. an EPA estimated 1000 pounds emitted by a typical supermarket.

GreenChill does not mandate any particular technology be used by stores seeking certification. Any store that meets the program’s refrigerant charge reduction and leak reduction standards can qualify.

It is not easy to achieve these standards. As of October 2010, there were only 39 certified stores in the nation. Some supermarket companies, such as Sprouts Farmers Market, have targeted achieving GreenChill certification for every new store they open. These companies often build the GreenChill certification requirements right into their new store specs. Their store designers, equipment manufacturers, and service technicians all work to meet the GreenChill standards. Sprouts currently has the most certified stores of any GreenChill partner.

Though no stores have met the challenge yet, GreenChill offers a special route to platinum certification for stores that only use refrigerants with global warming potentials of less than 350.

The GreenChill Advanced Refrigeration Program

GreenChill’s Advanced Refrigeration Program provides information to the supermarket industry on green refrigeration technologies, strategies, and practices. GreenChill has a monthly webinar series with expert speakers on commercial refrigeration topics of interest, a LinkedIn Group to promote information sharing, a website with GreenChill best practices guidelines and other information, quarterly partner meetings and, in future, monthly partner roundtable discussions.

GreenChill and Natural Refrigerants

As GreenChill approaches its third year, commercial refrigeration technologies using carbon dioxide and ammonia are gaining the interest of supermarket refrigeration engineers in the United States. GreenChill partners have five carbon dioxide cascade systems in use now in the United States, three of which are GreenChill-certified. Carbon dioxide is used as a secondary fluid in an increasing number of low-temperature secondary loop commercial systems in supermarkets. There are, as of yet, no ammonia commercial refrigeration systems in U.S. supermarkets, but the interest is there. GreenChill’s July and August webinars were on carbon dioxide and ammonia commercial refrigeration systems for supermarkets. Finally, discussions on GreenChill’s LinkedIn Group often feature an exchange of information on natural refrigerants.

Natural refrigerant use in industrial refrigeration systems is widespread in the U.S. Natural refrigerant use in supermarket commercial systems in Europe, Japan, and Australia is widespread. So why aren’t more natural refrigerants used in supermarket commercial systems in the U.S.? The answer, according to GreenChill, is a combination of real and perceived hurdles particular to the U.S. supermarket industry. The perceived hurdles can be overcome with information. The real hurdles can be overcome if the will is there. And it seems that the will may finally be there if GreenChill is any indication.

Natural Refrigerant Hurdles in U.S. Supermarkets

The number one hurdle is probably the confusing regulatory landscape in the U.S. Supermarkets must understand and observe the differing state and local regulations and codes for each and every store location, plus of course understanding and observing federal law. Much of this issue is perception. U.S. supermarkets are used to the laws and regulations that pertain to HCFC and HFC refrigerants. No one is eager to jump into a whole new can of worms. The benefits of “new” refrigerants would have to be measurable and worth it for supermarkets to voluntarily wade in there. Some of the issue is a real hurdle. Carbon dioxide was only recently found acceptable by EPA’s Significant New Alternative Policy Program (SNAP) for use as a primary refrigerant in commercial refrigeration. The SNAP Program found ammonia use as a primary refrigerant in supermarket secondary loop systems to be acceptable back in the mid nineties.

There are no major deterring regulations for the use of ammonia in supermarkets; however its classification as a B2 refrigerant restricts it from being used in occupied spaces. This can be bypassed however through the installation of a rooftop ammonia chiller, allowing any leaks to be safely directed to the atmosphere. In addition ammonia would not be subject to the OSHA and EPA’s Safety Management Plan which is only required for refrigerants over 10,000 pounds (whereas supermarkets would utilize only around 200 pounds of ammonia). Also, isolating the system to an outdoor unit allows the system to be classified as “low probability” by the International Mechanical Code (IMC), thereby exempting it from IMC ammonia restrictions.

Another hurdle is higher system costs. This hurdle must not be underestimated in an industry with very low profit margins. Because a lot of the equipment for commercial systems that use natural refrigerants must be imported from overseas, costs can be high for the first supermarkets to try these systems. Once the use of natural refrigerant equipment becomes more mainstream, the prices would be expected to fall. In addition, installation costs can be higher at first due to the need for commercial refrigeration service technicians to become used to working with new systems. Some believe that stores may be able to save in other areas, such as energy costs and lower maintenance costs, with these systems, but until hard data is available to prove that, such arguments are unpersuasive to many.

Training and education are always factors to be considered with new refrigerants and new refrigeration technologies. The lack of training can be a catch-22 situation. The lack of trained service technicians for a new technology is seen as a reason to avoid that technology; yet until stores exist with a new technology, there are few opportunities to receive the necessary training. Many HVACR professionals are familiar with ammonia, but their knowledge is limited to industrial systems. With adequate training this can be overcome, but first the demand for this knowledge must be there. Commercial refrigeration service technicians tend to fear the high operating pressures of CO2 systems. The only way to overcome this hurdle is through direct experience with these systems.

Finally, there is definitely a fear of increased corporate liability with ammonia and CO2 systems. Liability concerns are present with respect to shoppers and employees. An ammonia system where the ammonia is confined to rooftop units, with only glycol or CO2 circulating through the sales area should take care of the fear of liability for harm from ammonia to shoppers. Ammonia’s strong odor should minimize the danger of employees being overcome by ammonia fumes, as the odor is detectable well below the level deemed toxic. Further, safety standards developed for the industrial sector would be implemented to minimize risks.

With some will and work, the use of ammonia in supermarkets could develop into a common practice. This would be good not only for the environment and end user’s bottom lines, but it would also help the entire spectrum of the ammonia and CO2 refrigeration industry become more widely and easily accepted.