5 replies to this topic

CFC means Chloro - Fluoro-Carbons. They are hydrocarbons fully hallogenated with Chlorine and Fluorine. i.e.; CFC-11 (R-11) is dichloro-difluoro-methane. Others: CFC-12, CFC-115.

HCFC means Hydro-Chloro-Fluoro-Carbons: Some hydrogens are not substituted, and remains in the molecule. i.e.: HCFC-22 (R-22): Chloro-difluoro-methane. The hydrogen that remains in this molecule makes it easier to be oxidized in low atmosphere, so the greenhouse and ozone layer effect is quite lower than that of CFCs.

HFC: Hydro-Fluoro-Carbons. No chlorine is present. i.e. HFC-134a. 1,1,1,2 tetrafluoroethane. This compound has no effect on the ozone layer since chlorine is not present. The existence of hydrogen make possible the molecule to be oxidized in low atmosphere, so low greenhouse effect is expected.

PFC: Perfluorocarbons. No hydrogen remains in the molecule. i.e. R-218 = octafluoropropane. No effect on ozone layer, but a great greenhouse effect.

You can find all this information in ASHRAE web and refrigerants related sites.

Anyway, the greenhouse effect of all this gases, once eliminated from washing and degreasing procedures, is nelligible compared with the energy efficiency of refrigeration equipment. It is much more important to have an highly efficient refrigeration A/C system than the gas used inside it. The better efficiency the lower CO2 emissions from electricity production.

The greenhouse effect of the refrigeration gas itself represents about 1% of the whole impact of refrigeration equipment, measured as TEWI: Total Equivalent Warming Impact.

Good luck.

[javeline]

Hi Friend ,
Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases...



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[irvinelmo]

Hi,
CFC is the shorten of Chlorofluorocarbon.CFCs rise from the surface of the Earth and into the stratosphere where they're bombarded by UV light. We know that this releases the chlorine atoms that react with the ozone molecules and we know that before long, ozone becomes oxygen and we're left with less protection.While most countries have banned the usage of CFCs in aerosols, these gases are still found in refrigerators and in some types of foam packaging.

hmmm just got the meaning of all your question from the net. don't have any idea about...

CFC- Chlorofluorocarbons (CFCs), along with other chlorine- and bromine-containing compounds, have been implicated in the accelerated depletion of ozone in the Earth's stratosphere. CFCs were developed in the early 1930s and are used in a variety of industrial, commercial, and household applications. These substances are non-toxic, non-flammable, and non-reactive with other chemical compounds. These desirable safety characteristics, along with their stable thermodynamic properties, make them ideal for many applications--as coolants for commercial and home refrigeration units, aerosol propellants, electronic cleaning solvents, and blowing agents. Production and Use of Chlorofluorocarbons experienced nearly uninterrupted growth as demand for products requiring their use continued to rise.

HFC-Hydrofluorocarbons or 'HFCs' have been increasingly used in the last decade or so as an alternative to ozone damaging CFCs in refrigeration systems. Unfortunately, though they provide an effective alternative to CFCs, they can also be powerful greenhouse gases with long atmospheric lifetimes.

PFC-perfluorinated compound (PFC) is an organofluorine compound with all hydrogens replaced by fluorine on a carbon chain—but the molecule also contains at least one different atom or functional group. Thus, PFCs have properties similar to fluorocarbons (a wholly carbon and fluorine containing compound) as they are fluorocarbon derivatives. They have unique properties to make materials stain, oil, and water resistant, and are widely used in diverse applications. PFCs persist in the environment as persistent organic pollutants, but unlike PCBs, they are not known to degrade by any natural processes due to the strength of the carbon–fluorine bond.

here are the links if you want to read more about it ...............
http://www.ciesin.or.../OZ/cfcozn.html
http://www.ghgonline.../othershfcs.htm
http://en.wikipedia....nated_compounds

maybe this thing might help you.