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Refrigerant Replacement

The use of CFCs is not illegal, misuse is.

On December 31, 1995, the legal production of ozone depleting refrigerants (CFCs) ceased in the U.S.

With 80,000 commercial chillers installed in this country, the potential costs and ramifications to building owners and buyers can be significant. This issue of Engineering Advisor is an update on what has happened since January 1, 1996.

Why Discontinue Manufacturing Refrigerants?

CFCs (chlorofluorocarbons) and other variations such as hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are used as refrigerants in air conditioning and cooling equipment. Refrigerants are labeled as either CFCs, HFCs, or HCFCs, followed by a number. An older designation is to use the letter R, followed by the number. The manufacture of CFC refrigerants has been phased out. Others will be phased out early in the next century.

In the stratosphere, a layer of ozone (an allotrope of oxygen with three atoms) protects us from ultraviolet radiation. In the 1970s, it was discovered that certain compounds, most notably CFCs, when released into the atmosphere tend to react with ozone, removing one of the atoms, weakening its ultraviolet blocking ability.

In 1987, representatives from around the world met in Montreal. The result was what is now known as The Montreal Protocol wherein participating nations agreed to limit the production and use of these chemicals. In the U.S., the Montreal Protocol was superseded by the Clean Air Act of 1990, as amended in 1992.

 

How Large is the Problem?

For the building owner, there are two types of cooling systems to be considered:

  • Smaller Stationary Units. These deliver cold air directly to a room or space. They typically include roof-top equipment, through the wall systems, and split systems with capacities generally up to 60 tons.
  • Larger Stationary Units. (central systems). These deliver cooling via chilled water. The central chiller cools the water which is circulated through coils and air is blown over these chilled water coils. These units range from 100 to more than 2,000 tons. There are about 80,000 of these larger units in operation today.

How Have Building Owners and Managers Responded?

"The use of CFCs is not illegal, misuse is.1"

They must be handled properly and releases into the air are prohibited. Therefore, it is largely the servicing of commercial equipment that is regulated. The technician performing the work must be certified and must follow specific guidelines.

In smaller systems, undetected leaks are not likely since the compressor and motor are hermetically sealed in the same housing. If leaks occur, they are usually accompanied by a loss of cooling, signifying a need for service.

For owners of buildings with smaller stationary systems, the most important consideration is ensuring that servicing is performed properly. It is the responsibility of the facilities manager to understand the EPA regulations and ensure that any technicians he uses comply. Since the refrigerant most often used in these systems is an HCFC (R-22) which is still in production, and since these systems are replaced several times during the life of the building, there is less concern over such systems in existing buildings.

Owners of larger, central equipment, or chillers, have added concerns. The equipment will last many years. Leakage occurs naturally as well as during servicing. Automatic or manual procedures to purge the system of air naturally result in releases of refrigerant. Leakage is of concern because it is regulated. Commercial refrigeration (e.g. cold storage) or industrial process refrigeration equipment may not lose more than 35 percent of its charge during a 12 month period. For other systems that contain more than 50 pounds of refrigerant (many office, hotel and multifamily buildings), the maximum leakage permitted is 15 percent. Leakage is generally detected by recording the amount of refrigerant added during servicing and periodic monitoring is recommended.

Furthermore, chillers most frequently use CFC 11, 12, 113, 114 and R500, the types no longer being produced. They are available only by recovery, recycling or reclamation (and, unfortunately, some illegal smuggled supplies). It was feared that the cost for CFC refrigerants would become exorbitant and ultimately, supplies would be unavailable. The cost has certainly increased dramatically, but no real shortage exists. This is especially true for managers of multiple properties who can reclaim or recycle refrigerant from properties in which the chiller has been replaced or taken off line.

That situation will change. In 1992, J.A. Krol, Vice Chairman of DuPont said that we "should be converting 2,000 centrifugal chillers a month." The Air-Conditioning and Refrigeration Institute (ARI) reported that 4,356 chillers were replaced in 1996, 1,514 fewer than projected and far less than Mr. Krol had recommended. DuPont estimates that existing chillers will lose 10 percent of their refrigerant (through purges and accidents) each year. With the only supply of CFCs coming from existing equipment, there will be a time in the not too distant future when supplies will be inadequate.

Conclusion

To comply with the Clean Air Act, three strategies are commonly employed: containment of the refrigerant (almost always a first priority), replacement of the chiller (function of size, age, efficiency and economics), or conversion of the refrigerant used in the chiller (a complex design issue). We recommend that building owners plan to address the refrigerant issue by referencing current laws for various refrigerant types (and changes as they occur), prescribe management and maintenance procedures, and evaluate the best way to discontinue the use of CFCs such as conversion or replacement.

1 Complying with the CFC Provisions of the Clean Air Act, Government Institutes, Inc., Rockville, MD, 1994

 

The Engineering Advisor is intended to enhance your knowledge of technical issues relating to buildings. For additional information on any subject, please feel free to call us. Our commitment is to provide you with timely, accurate information.

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