Ozone (O3), the key substance of the protective ozone layer, is naturally created and destroyed by chemical reactions in the stratosphere. When chlorine is present in the stratosphere, it upsets the natural ozone layer balance by destroying O3 faster than it is naturally replaced. It is the chlorine present in CFCs (Chlorofluorocarbons) and HCFCs (Hydrochlorofluorocarbons) that causes ozone depletion.

In order to reduce and eliminate ozone depletion, the Montreal Protocol required production and importation of CFCs in The United States and other developed countries to be halted at the end of 1995. Under this protocol, the United States has started phasing out the production and importation of HCFCs. This is of particular importance to the refrigeration and air conditioning industry because HCFC-22 or R-22 is the world’s most widely used refrigerant. It serves in both residential and commercial applications, from small window units to large commercial water chillers, and everything in between. HCFC-22 Ozone Depletion Potential (ODP) is as much as 95% lower than CFCs. Nevertheless, it does have some ODP, so international law set forth in the Montreal Protocol and its Copenhagen and Vienna amendments have put HCFC-22 on a phase-out schedule. In developed countries, production of HCFC-22 will end no later than the year 2030. In intervening years, production is reduced in a series of specified steps.

Detailed phase-out schedules vary from country to country. In the U.S., HCFC-22 production will be frozen at baseline levels on January 1, 2010, and the production of virgin refrigerant will be banned unless it is used as a feedstock for other refrigerants, or in equipment manufactured prior to January 1, 2010. The countries of the European Community have adopted even stricter measures.

What are the Options?

There are a wide variety of options available to replace both HCFC refrigerants and equipment or systems. The most widely accepted replacement option for HCFCs is the use of hydrofluorocarbons (HFCs). Ammonia is also a replacement option in the large commercial air conditioning and refrigeration sectors. These refrigerants do not deplete the ozone layer and can replace both CFC and HCFC uses. A brief overview of options classified by general equipment groups is as follows:

• Residential and Commercial Air Conditioning

Almost 100% of residential and commercial air conditioning equipment (excluding large air conditioning systems called chillers) has traditionally operated on HCFC-22. The current refrigerant alternatives for residential and commercial air conditioning equipment are HFC blends. Some of these blends can be applied to existing equipment with modifications to the systems. Others can only be used with new equipment designed for the specific refrigerant blend.

• Large Air Conditioning Systems (Chillers)

Large air conditioning systems or chillers use either high or low-pressure refrigerants. Low-pressure chillers have traditionally used a CFC refrigerant (CFC-11). The current alternative refrigerant for low-pressure chillers is HCFC-123. This refrigerant will be manufactured/imported until 2030 for use in servicing these systems; however, other alternative low-pressure HFC refrigerants (such as HFC-134a) are being implemented.

The HCFC Phase-out Schedule

HCFCs are a controlled substance because of their ozone-depleting potential. Importation and manufacturing of new or "virgin" HCFCs is regulated by a federal allowance system. The United States government has adopted the following phase-out schedule for HCFCs based on the terms of the Montreal Protocol:

What does the HCFC Phase-out mean and what should be done?

The majority of the HCFC phase-out impact from a standpoint of refrigerant availability (e.g. R-22) will be felt over the next eight years. By January 1, 2010, 65% of the current annual supply of HCFC refrigerants will be eliminated from the marketplace and R-22 equipment will not be manufactured or imported. Awareness of the phase-out schedule and available alternatives will become more important as the decade progresses and contractors, equipment specifiers and equipment owners consider replacement and servicing of new and existing refrigeration and air conditioning equipment.

Equipment Owners (including Homeowners)

Equipment owners today are mostly unaware of the HCFC phase-out and its implications. The life cycle of HCFC refrigeration and air conditioning equipment can be as little as 10 years and as long as 30 years depending on the type of equipment. Residential central air conditioning units last between 10 and 15 years. Supermarket refrigeration equipment has a typical life span of approximately 15 years. Large air conditioning units (chillers) can last as long as 30 years. Equipment owners need to start considering the potential impact of the HCFC phase-out when considering new equipment and retrofits of existing equipment with their service contractor or equipment specifier.

Owners of HCFC equipment or those customers who are contemplating purchases of new refrigeration and air conditioning equipment need to make themselves aware of the issues surrounding HCFC refrigerants. The best source for this information should be a refrigeration and air conditioning contractor or equipment specifier, who can provide this information and assist owners in choosing the proper equipment or refrigerant to meet their needs.

Commercial and industrial owners should invest time in reviewing their current stock of refrigeration and air conditioning equipment. Once this is completed, they should discuss with a contractor or equipment specifier both short and long term plans for their equipment needs and the effects the HCFC phase-out will have on these needs.

HCFC phase-out considerations when planning for replacement or retrofit of HCFC equipment should include:

A key partner in these considerations should be a Mechanical Engineer, the refrigeration and air conditioning contractor and equipment supplier.

R-410A, the next step. What you need to know.

The industry worldwide has developed a wide variety of long term refrigerant alternatives that are classified as HFCs (Hydrofluorocarbons). HFCs are now available for most refrigeration and air conditioning applications. In the area of unitary air conditioning, the industry manufacturers have primarily moved towards HFC-410A as the replacement for R-22 in NEW equipment. The characteristics of R-410A are considerably different than that of R-22, and while no specific R-410A training is mandated, technicians should be knowledgeable and have the proper tools to safely handle this refrigerant.

Operating pressures in a R-410A refrigerant system average about 60% higher than in a comparable R-22 system. At first, this may seem to be a negative characteristic. In fact, just the opposite, the higher pressures have led equipment system designers to more robust designs, superior control and protection techniques. As a result, system reliability was not compromised but actually improved.

Because R-410A refrigerant is not a direct, functional replacement for R-22, equipment must be specifically designed to operate with R-410A. R-410A refrigerant units are designed for heavy-duty operation with a thicker compressor shell and heavy-wall tubing. Thicker materials in turn enabled the manufacturer to create heavier, better welds at joints, which improve their resistance to abuse. The field-testing and product history to date for R-410A equipment suggest that the R-410A units are more reliable than R-22 units.

Lubricants

All air conditioners and heat pumps using scroll and reciprocating compressors circulate oil with the refrigerant to keep the compressor lubricated. R-22 units use mineral oil. Most air conditioning and heat pump units operating with HFC refrigerants such as, R-32, R-125, R-134a, R-143a and their mixtures, including R-410A refrigerant, are recommended to use synthetic lubricants. Synthetic lubricants are not uncommon and are commercially available.

Synthetic lubricants are more soluble with R-410A refrigerant than traditional mineral oils are with R-22. Improved solubility allows the oil to mix easier with R-410A refrigerant and circulate more efficiently. Overall, this improves oil return, reduces compressor wear and generally improves reliability. Also, just like synthetic motor oils used in automobiles, synthetic oils circulating with R-410A refrigerant are less likely to breakdown under extreme service conditions. This serves as another benefit to achieving greater system reliability.

The one challenge with synthetic lubricants is that they are prone to absorb moisture from the atmosphere due to polarity of the molecules and ability to attract water molecules. This requires service technicians to take simple precautions to prevent exposing the oil to air. It is as simple as keeping the oil container sealed and transferring oil with a pump rather than pouring it. But, if the oil, as well as R-410A refrigerant, does absorb a small amount of moisture, each refrigerant system should contain a filter-dryer with the express purpose of cleaning and drying refrigerant and oil circulating through the system.

R-410A Characteristics

Pressure-Temperature Chart for R-410A and R-22