A refrigerant global warming potential gwp is based on a ratio of the refrigerants. In 1987 a conference was held where it was decided to phase out the production of cfcs and develop the suitable substitute refrigerants that have no ozone depletion potential. Although these refrigerants have zero ozone depletion potential odp and minimal global warming impact due to. Ozone depletion potential of different refrigerants. Ozone depletion potential odp the depletion of the ozone layer is driven primarily by the catalytic action of chlorine, fluorine and bromine in compounds, which split up ozone molecules o 3, thus destroying the ozone layer. Cfcs were replaced with hcfcs, which have lower ozonedepletion potential odp, or with. The greatest concentration of ozone are found from 12 km to 50 km above the earth forming a layer in the stratosphere which is called the ozone layer. A number of alternative refrigerants have been developed and still many more new are being developed. Epa approves three alternative refrigerants to replace hfcs. Most of the cfcs and hcfcs causing ozone layer depletion and greenhouse effect are already being phased out. Although it has zero ozone depletion potential, it has high global warming potential, 3400 times that of carbon dioxide, based on a 100year time frame. Ozone depletion and global warming are two major environmental concerns with serious implications for the future development of the refrigerationbased industries.
In particular, property managers must oversee the proper management of refrigerants and refrigerantcontaining. Pdf ozone depletion potential of different refrigerants. Stratospheric ozone depletion is a global threat to the balance of nature resulting in a decreasing concentration of ozone particles in the upper atmosphere. Policylegislation on fgases and alternatives two environmental frameworks. Refrigerants can thus also be ranked according to their impact on the stratospheric ozone layer the ozone depletion potential, odp or as greenhouse gases the global warming potential, gwp. Natural refrigerants sustainable ozone and climatefriendly alternatives to hcfcs introduction dr. Stratospheric ozone depletion and hvac refrigerants. Performance investigation of ozonefriendly r404a and r507 refrigerants as alternatives to r22 in a window airconditioner.
Along with prohibiting the production of ozonedepleting refrigerants, the clean air act also mandates the use of common sense in handling refrigerants. Ozonedepleting substances ozone layer protection us epa. Odp values are used to provide a simple way to compare the relative ability of various ods to destroy stratospheric ozone. Zero ozone depletion potential replacement for r22. How does ozone affect ultra violet radiation that can lead to skin damage. Have a look at question 4 in this link is to the united nations environment programme scientific assessment panel site where they answer some of the faqs. Thus, banning the use of cfcs in refrigerants not only slows the depletion of the ozone layer but also reduces the humancaused component of global warming. The odp or ozone depletion potential, is the potential for a single molecule of the refrigerant to destroy the ozone layer.
Refrigerants are regulated as hazardous materials by the us epa and carb, due to their ozone depleting ability and powerful greenhouse gas potential. Linde strongly advocates the use of refrigerant gases with zero ozone depletion. It went into effect in 1987, first targeting cfcs, then hcfcs. Terms in this set 27 ozone blank is a numeric value assigned to refrigerants to compair how harmful they can be to the ozone. Ozone depleting substances refrigerant reclaim australia. Odp is ozone depletion potential of with re ference to cfc r11 as 1. Growing demand for refrigeration and airconditioning with diversified applications has led to a continued search. The antarctic ozone hole is a dramatic demonstration of the environmental impact caused by emissions of cfcs, hcfcs and other ozone depleting substances ods that release chlorine and bromine as they break down in the stratosphere. When these substances reach the upper atmosphere, they create chemical reactions which cause the ozone molecules in the atmosphere to break down. They also have good energy efficiency, but are flammable and can form an explosive mixture with air if a leak occurs. A compounds ozone depletion potential odp is shown as its equivalent in chlorine odp of a chlorine molecule 1. Refrigerants containing chlorine or bromine contribute to the breakdown of the ozone layer see figure 5. This factor is one for r11, as it has maximum potential to destroy the ozone layer. In the 1980s, cfcs and hcfcs were determined to play a major role in depleting the stratospheric ozone layer.
By containing and using refrigerants responsiblythat is, by recovering, recycling, and reclaiming and by reducing leakstheir ozonedepletion and globalwarming consequences are minimized. Ozone is a variant of oxygen, the ozone molecule having three atoms of oxygen. Global warming potential gwp is a relative measure of how much heat a refrigerant traps in the atmosphere. Ozone depletion and global warming overview page 1 of 5 halocarbons are chemical compounds containing carbon, one or more halogens, and sometimes hydrogen. The regulation for the management of high global warming potential refrigerants for stationary sources carb. Calculating ozone depleting potentials odp introduction the number of single component refrigerants with different thermodynamic properties suitable for different types of equipment is limited. In most cases no timeconsuming circuit rinsing is required. All of the refrigerants use r11 as a datum reference and thus r11 has an odp of 1. Explain ozone depleting potential of conventional refer. The ozone depletion potential odp of a refrigerant is the relative amount of depletion to the ozone layer it can cause. R427a like other gases such as r407c is a zeotrope. Hfcs and natural refrigerants are both developed to. In addition to their ozone depletion effects, cfcs in the stratosphere also absorb outgoing infrared radiation from the earth, functioning as potent greenhouse gases. Beginning in the 1930s, cfcs were widely used as refrigerants in home refrigerators and air conditioners, cleaning solvents, and as foamblowing agents for making things like egg cartons and coffee cups.
Developing more environmentally friendly refrigerants. Product information sorted by product type and name type product r number. The ozone depletion potential odp of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane r11 or cfc11 being fixed at an odp of 1. Add r427a, with an initial charge of 95% of the original weight. Some halocarbons ozone depleting substances, or odss deplete the ozone layer, while others greenhouse gases, or ghgs are thought to contribute to global warming. Compared to halogenated refrigerants, hydrocarbons like isobutane r600a and propane r290 offer several advantages. After a series of rigorous meetings and negotiations, the.
Different substances break down ozone more rapidly than others. Ozone depletion potential of different refrigerants and their solution. Odp is defined as the integrated change in total ozone per unit mass. The effects on the industry of the actions to reduce ozone depletion and global warming are now apparent. Ozone depletion potential odp of a chemical compound is the relative amount of degradation it can cause to the ozone layerglobal warming potential gwp is a measure of how much a given mass of a gas contributes to global warming. Indicators for quantitative comparison of the various sub. The negative influence of refrigerants on the climate and the immediate environment in terms of their higher global warming potential gwp and ozone depletion potential odp has prompted this study. Refrigerants and cfcs a major cause of ozone layer depletion. Pdf refrigerant types, issues, trends and future options. Introduction under the montreal protocol on substances that deplete the ozone layer, article 7 of the protocol requires all parties, both developing countries also called article 5 countries and developed countries. This table provides up to date internationally recognised data on the ozone depletion potential and global warming potential of the gases, as well as an easy reference summary of their impact. Unlike alkyl halide refrigerants that contain bromine or chlorine, r410a which contains only fluorine does not contribute to ozone depletion and is therefore becoming more widely used, as ozonedepleting refrigerants like r22 are phased out.
Common refrigerants and their ozone depletion potential odp and global warming potential gwp are indicated below. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule. Volkmar hasse, gtz proklima, germany preface volkmar hasse, gtz proklima i. While nist actually, then still the national bureau of standards wasnt yet concerned with finding replacements. Measurements of chlorine within the antarctic ozone hole from nasas aura satellite. The conventional cooling systems use refrigerants with high ozone depletion potential odp and greenhouse gas ghg impact and as a consequence the prohibition of. The green globes rating system accounts for ozone depletion, global warming and leak detection. R4a tetrafluoroethane is an environmental nonozonedepleting refrigerant, the cooling capacity and efficiency and r12 is very close, they were regarded as longterm alternative to r12. The compatibility with the environment has become an essential criterion when a new refrigerant is selected to alternate cfcshcfcs. By following the criteria in the rating systems, the selected refrigerants can help the project achieve points toward green building status.
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