OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
ALTERNATIVES OF FREONS
Praveen
M.Tech student, YMCAUST,3 RD SEM, praveenchch@gmail.com
ABSTRACT
So both the chlorine and fluorine play role in the depletion of ozone layer .Chlorofluoro-carbons are responsible
for the depletion of ozone layer. Hence all the CFCs like R11,R12,R113,R115,R502 are being phased out. So we
need some alternatives. First alternative we found are HCFC.in this type of refregerants hydrogen is added to
the CFCs . HCFCs are compounds containing carbon, hydrogen, chlorine and fluorine. The HCFCs have
shorter atmospheric lifetimes than CFCs and deliver less reactive chlorine to the stratosphere where the "ozone
layer" is found. . Because they still contain chlorine and have the potential to destroy stratospheric ozone, they
are viewed only as temporary replacements for the CFCs.Ozone layer depletion by CFCs occurs by breakdown
of chlorine atoms from refrigerants by UV radiation and reaction with ozone in stratosphere.Florine carry the
chlorine atoms up to the stratosphereSecond alternatives we found are HFCs.Hydrofluorocarbons (HFCs) are
compounds containing carbon, hydrogen, and fluorine. Because the HFCs contain no chlorine they do not
directly affect stratospheric ozone. It has been postulated that extensive use of these chemicals in the future
could contribute significantly to enhanced radiative atmospheric heating.The future replacement of CFCs as
refrigerants areAmmonia in vapor compression systems, Carbon dioxide in vapour compression systems etc.
1. INTRODUCTION
A chlorofluorocarbon (CFC) is an organic compound that contains only carbon, chlorine, hydrogen and fluorine,
produced as a volatile derivative of methane and ethane. They are also commonly known by the DuPont brand
name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have
been widely used as refrigerants, propellants (in aerosol applications), and solvents. The manufacture of such
compounds has been phased out (and replaced with products such as R-410A) by the Montreal Protocol because
they contribute to ozone depletion in the upper atmosphere.
With the phased outof CFCs for the good of the ozone, decisions have to be made about replacing or converting
existing refrigerants and refrigerant systems. There are three basic choices when deciding whether to repair or
replace equipment containing refrigerants. The first option is to fix the equipment, recharging it with the original
refrigerant, if it is available. Retrofitting should be considered if the original refrigerant has been phased out, like
CFC-12. Many types of equipment can be retrofitted to use an alternative refrigerant. Retrofitted equipment
typically has lower efficiency and less capacity than new equipment. The third choice is to replace the unit. This
option has the highest initial cost, but in many cases may be the cheapest over the lifetime of the equipment,
especially in vehicles, refrigerators, chillers, and central units. However, this may not be the case in industrial
sized AC units due to the area over which the unit operates.
Choosing between the options can be difficult. Economic and environmental factors play an important part in
any decision, especially one that involves decreasing the amount of damage done to the ozone layer. Life-cycle
cost analyses can help you select an economically practical option. Some of these life-cost analyses are presented
below.
The Montreal Protocol on Substances that Deplete the Ozone Layer (a protocol to the Vienna Convention for the
Protection of the Ozone Layer) is an international treaty designed to protect the ozone layer by phasing out the
production of numerous substances believed to be responsible for ozone depletion. The treaty was opened for
signature on September 16, 1987, and entered into force on January 1, 1989, followed by a first meeting
in Helsinki, May 1989. Since then, it has undergone seven revisions, in 1990 (London), 1991 (Nairobi), 1992
(Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), and 1999 (Beijing). It is believed that if the
international agreement is adhered to, the ozone layer is expected to recover by 2050. [1] Due to its widespread
adoption and implementation it has been hailed as an example of exceptional international co-operation,
with Kofi Annan quoted as saying that "perhaps the single most successful international agreement to date has
been the Montreal Protocol". [2] The two ozone treaties have been ratified by 197 states and the European
Union [3] making them the most widely ratified treaties in United Nations history. [4]
Chlorofluorocarbons (CFCs) Phase-out Management Plan
The stated purpose of the treaty is that the signatory states "Recognizing that worldwide emissions of certain
substances, including ST, can significantly deplete and otherwise modify the ozone layer in a manner that is
likely to result in adverse effects on human health and the environment, ... Determined to protect the ozone layer
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