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Scientific data supports the hypothesis that chlorine from refrigerants has depleted the earth's  ozone layer and is linked to a rise in skin-related diseases, as outlined by Annika Nilsson in her book Ultraviolet Reflections: Life Under A Thinning Ozone Layer.

The air conditioning and refrigeration industry has supported global efforts to protect the environment by introducing non-chlorine-containing refrigerants.

The Montreal Protocol, established in 1987 and later revised, provides guidelines for individual country legislation, setting timetables for the phase-out of chlorine-containing refrigerants.

Today, 196 nations have become party to the Montreal Protocol.

Carbon dioxide is by far the most significant greenhouse gas, produced mainly by burning fossil fuels for electrical generation and transportation.

Since refrigeration equipment consumes energy, energy-efficient designs are important to reducing carbon dioxide production.

If refrigerant gas escapes from a system, it can also contribute directly to global warming.

For a refrigerant to be considered a long-term option, it must meet three criteria:
1) It must be safe
2) It must be environmentally friendly
3) It must provide excellent performance benefits, thus resulting in zero ozone depletion with low global warming potential (GWP).

Several non-halogen substances, including ammonia, carbon dioxide and hydrocarbons, will also work as refrigerants.

All of these substances can be refrigerants for the right application if the system can be designed to meet key selection criteria.

Hydrofluorocarbons (HFCs) are non-ozone depleting, nonflammable, recyclable and energy-efficient refrigerants of low toxicity that are used safely worldwide.

Although HFCs are the best environmental and economic choice today, the global sustainability of HFCs requires a focus by the industry on refrigerant containment and energy efficiency.

Many now believe in a holistic approach when it comes to selecting refrigerants based upon life cycle climate performance (LCCP). LCCP takes into account both the direct (leak rate, charge amount, refrigerant GWP) and indirect (energy consumed, source of energy) global warming effects.
 
Emerson promotes the idea that responsible use is the key to safety and environmental stewardship and containment is one way to accomplish this.

Equipment manufacturers are working to design systems that require less charge and have fewer leaks.

The Alliance for Responsible Atmospheric Policy (ARAP), a leading voice that coordinates industry participation in the development of international and US government policies regarding ozone protection and climate change, has developed a list of best practices to properly handle refrigerants.

These include:

Contain refrigerants in tight or closed systems and containers, lowering atmospheric releases

Encourage monitoring after installations to lower direct refrigerant emissions and to maintain energy efficiency

Train all personnel in proper refrigerant handling

Comply with standards on refrigerant safety, proper installation and maintenance (ASHRAE-15, ISO-5149 and European Standard EN378)

Design, select, install and operate to increase energy efficiency

Recover, recycle and reclaim refrigerants

Continue to improve equipment energy efficiency when cost effective.

It is important to recognise that this is an evolutionary process. Today's HFCs are the next steps, but they are not the last steps in the process. As technologies develop and new applications and system designs continue to emerge, other refrigerants may be developed and applied.

No HFC refrigerant can cause direct global warming if it is properly contained. In the HVACR industry, we expect to see more emphasis on refrigerant recovery and leak prevention.

A more comprehensive guide to refrigerant usage in commercial applications can be found on Emerson's website at www.emersonclimate.com 

About the author - Dr Rajan Rajendran is vice president, engineering  services and sustainability at Emerson. He serves on the low GWP alternative refrigerants evaluation program task force of the Air Conditioning and Heating Institute  and on the working groups for A2L refrigerants at Underwriters Laboratories.

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