It went into effect in 1987, first targeting cfcs, then hcfcs. The problem of global warming must be considered while focus is fixed upon the problem of ozone depletion. Frank sherwood row land, professor of chemis try at the university o f california, irvine and mar io. The ozone depletion potential odp of a refrigerant represents its effect on atmospheric ozone, and the reference point usually adopted is odp 1 for the cfc r11. Performance investigation of ozonefriendly r404a and r507 refrigerants as alternatives to r22 in a window airconditioner. Different substances break down ozone more rapidly than others. Cfcs and hydrochlorofluorocarbons hcfcs has been the high global warming potential of some hydrofluorocarbons hfcs used as substitutes, despite their. This is measured by their ozonedepletion potential odp. The conventional cooling systems use refrigerants with high ozone depletion potential odp and greenhouse gas ghg impact and as a consequence the prohibition of. Most of the cfcs and hcfcs causing ozone layer depletion and greenhouse effect are already being phased out.
Global warming potential gwp is a relative measure of how much heat a refrigerant traps in the atmosphere. Measurements of chlorine within the antarctic ozone hole from nasas aura satellite. 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. R4a is widely used in automotive air conditioning and residential, commercial and industrial refrigeration systems, but also as a blowing agent for rigid foam insulation materials production. A number of alternative refrigerants have been developed and still many more new are being developed. In addition to their ozone depletion effects, cfcs in the stratosphere also absorb outgoing infrared radiation from the earth, functioning as potent greenhouse gases. Without the ozone layer, wed all need to wear a lot more sunscreen. 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. 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. The ozone depletion potential odp of a refrigerant is the relative amount of depletion to the ozone layer it can cause. This factor is one for r11, as it has maximum potential to destroy the ozone layer. Ozonedepleting substances ozone layer protection us epa. Ozone depletion and global warming are two major environmental concerns with serious implications for the future development of the refrigerationbased industries.
Odp values are used to provide a simple way to compare the relative ability of various ods to destroy stratospheric ozone. The compatibility with the environment has become an essential criterion when a new refrigerant is selected to alternate cfcshcfcs. Some of these refrigerants are entirely new ones, while the others are the mixture of two or more refrigerants. The regulation for the management of high global warming potential refrigerants for stationary sources carb. Stratospheric ozone depletion and hvac 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. Some halocarbons ozone depleting substances, or odss deplete the ozone layer, while others greenhouse gases, or ghgs are thought to contribute to global warming. While nist actually, then still the national bureau of standards wasnt yet concerned with finding replacements. Indicators for quantitative comparison of the various sub. They also have good energy efficiency, but are flammable and can form an explosive mixture with air if a leak occurs. Developing more environmentally friendly refrigerants. Linde strongly advocates the use of refrigerant gases with zero ozone depletion.
Odp is defined as the integrated change in total ozone per unit mass. 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. Ozone depletion potentials odps were a very important measure in the formulation of the montreal protocol and its amendments. Ozone depleting substances refrigerant reclaim australia. 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. Pdf ozone depletion potential of different refrigerants. The effects on the industry of the actions to reduce ozone depletion and global warming are now apparent. Add r427a, with an initial charge of 95% of the original weight. Compared to halogenated refrigerants, hydrocarbons like isobutane r600a and propane r290 offer several advantages. By following the criteria in the rating systems, the selected refrigerants can help the project achieve points toward green building status. By containing and using refrigerants responsiblythat is, by recovering, recycling, and reclaiming and by reducing leakstheir ozonedepletion and globalwarming consequences are minimized.
Volkmar hasse, gtz proklima, germany preface volkmar hasse, gtz proklima i. How does ozone affect ultra violet radiation that can lead to skin damage. Chlorodifluoromethane r22, for example, has an odp of 0. Common refrigerants and their ozone depletion potential odp and global warming potential gwp are indicated below. 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 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. Epa approves three alternative refrigerants to replace hfcs. R427a like other gases such as r407c is a zeotrope. 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. A refrigerant global warming potential gwp is based on a ratio of the refrigerants. The green globes rating system accounts for ozone depletion, global warming and leak detection. 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. In the 1980s, cfcs and hcfcs were determined to play a major role in depleting the stratospheric ozone layer.
Refrigerants containing chlorine or bromine contribute to the breakdown of the ozone layer see figure 5. Explain ozone depleting potential of conventional refer. A compounds ozone depletion potential odp is shown as its equivalent in chlorine odp of a chlorine molecule 1. Terms in this set 27 ozone blank is a numeric value assigned to refrigerants to compair how harmful they can be to the ozone. In particular, property managers must oversee the proper management of refrigerants and refrigerantcontaining. Ozone is a variant of oxygen, the ozone molecule having three atoms of oxygen. Ozone depletion and global warming overview page 1 of 5 halocarbons are chemical compounds containing carbon, one or more halogens, and sometimes hydrogen. 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. Policylegislation on fgases and alternatives two environmental frameworks. 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. The second generation of refrigerants included chlorofluorocarbons cfcs and hydrochlorofluorocarbons hcfcs, which became widely used because they were efficient, nonflammable, and nontoxic.
Hfcs and natural refrigerants are both developed to. After a series of rigorous meetings and negotiations, the. Although these refrigerants have zero ozone depletion potential odp and minimal global warming impact due to. Calculating ozone depleting potentials odp introduction the number of single component refrigerants with different thermodynamic properties suitable for different types of equipment is limited. Growing demand for refrigeration and airconditioning with diversified applications has led to a continued search. Refrigerants and cfcs a major cause of ozone layer depletion. Zero ozone depletion potential replacement for r22. All of the refrigerants use r11 as a datum reference and thus r11 has an odp of 1. In most cases no timeconsuming circuit rinsing is required. Pdf refrigerant types, issues, trends and future options. Product information sorted by product type and name type product r number. Ozone depletion potential of different refrigerants and their solution.
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. Odp is ozone depletion potential of with re ference to cfc r11 as 1. Stratospheric ozone depletion is a global threat to the balance of nature resulting in a decreasing concentration of ozone particles in the upper atmosphere. Ozone depletion potential of different refrigerants. Along with prohibiting the production of ozonedepleting refrigerants, the clean air act also mandates the use of common sense in handling refrigerants. 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. 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. 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. Natural refrigerants sustainable ozone and climatefriendly alternatives to hcfcs introduction dr. When these substances reach the upper atmosphere, they create chemical reactions which cause the ozone molecules in the atmosphere to break down. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule. Performance investigation of ozonefriendly r404a and r507.