The interaction between climate change and ozone depletion. Ozone depleting substances department of agriculture, water. Choice of natural refrigerants makes no net addition of the greenhouse gases ghg in the environment. One chlorine atom has the potential to destroy more than 100,000 ozone molecules. Ii flame limits measured using astm e681 with electrically activated kitchen ignition source per ashrae standard 34. Some ozonedepleting potential for refrigerants are shown in table 3. Refrigerant types, issues, trends and future options. A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. Calculating ozone depleting potentials odp introduction the number of single component refrigerants with different thermodynamic properties suitable for different types of equipment is limited. Add r427a, with an initial charge of 95% of the original weight. In most cycles it undergoes phase transitions from a liquid to a gas and back again. Ozone depleting substances department of agriculture.
It is found that hcfcs generally have much lower ozone depletion potential odp and global warming potential gwp in. Ozone depletion potential article about ozone depletion. Compared to halogenated refrigerants, hydrocarbons like isobutane r600a and propane r290 offer several advantages. Linde strongly advocates the use of refrigerant gases with zero ozone depletion potential and fully supports the phase out of hcfcs. Ozone is also a greenhouse gas, but most of the warming effect comes from troposheric ozone. Stratospheric ozone protects us from ultraviolet rays. However, owing to some regulations and limitations in the recent years, tendency to refrigerants having low global warming potential gwp has increased.
Footscray, victoria table 1 global warming and ozone depletion potential of anaesthetics chemical formula lifetime yrs isoflurane chf. Although hcfc22 production is controlled for refrigerant. Odp is ozone depletion potential of with re ference to cfc r11 as 1. R 123 will be phased out for new hvac equipment on january 1, 2020 because of the ozone depletion potential oop. Understanding a2l refrigerants for air conditioners 201908.
The linkage of the cfc refrigerants to the destruction. Refrigerants bearing high global warming potential gwp and ozone depletion potential odp were outlawed or facing timebeared permission under the montreal 1987, kyoto 1997 protocols, fgas. This is the process of ozone depletion and has already caused a substantial amount of damage to the ozone layer. Nonozone depleting substances ods do not deplete the earths protective ozone layer. This is measured by their ozone depletion potential odp. Under this circumstance, natural refrigerants such as nh3, hc and co 2 are thus obtaining more and more favour because of their very low environmental impact. Significant new alternatives policy snap program us epa. Montreal protocol agreement for reducing odp refrigerants. Cfcs were replaced with hcfcs, which have lower ozonedepletion potential odp, or with. An hvac chillers life span of 2530 years makes any r 123 dependent chiller purchased today virtually obsolete.
Significant new alternatives policy snap program snap was established under section 612 of the clean air act to identify and evaluate substitutes for ozonedepleting substances. The road to lowglobal warming potential alternatives. Understanding a2l refrigerants for air conditioners 2019. The last round of changes took place between the mid1990s through 2010, as cfc and hcfc refrigerants were phased out and largely replaced by hfcs. Since india already receives high doses of ultraviolet uvb radiation, and is at the threshold go to speak, effects of ozone layer depletion.
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. Dec 20, 2019 a significant reduction in the consumption of ozone depleting substances ods has been achieved by the eea33 countries since 1986. Odp is defined as the integrated change in total ozone per unit mass. All of the refrigerants use r11 as a calibration and thus r11 has an odp of 1. This website addresses stratospheric ozone issues, including the science of ozone depletion, epas regulatory approach to protecting the ozone layer, epa. Ozone depletion potentials odps were a very important measure in the formulation of the montreal protocol and its amendments. Global warming potential gwp is a measure of how much a given mass of a gas contributes to global. Natural and synthetic refrigerants, global warming. The odp or ozone depletion potential, is the potential for a single molecule of the refrigerant to destroy the ozone layer.
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. Refrigerants and cfcs a major cause of ozone layer depletion. Leak repair to determine compliance with regulations, need to determine the leak rate. Odp is the ratio of ability of a substance to degrade ozone, to that of chlorofluorocarbon11 cfc11, which therefore, has a value of 1. A viable lowgwp candidate must possess a number of other attributes 6, including zero or very low ozone depletion potential, chemical stability within the refrigeration system, thermodynamic. The regulation for the management of high global warming potential refrigerants for stationary sources carb. The odp, or ozone depletion potential, is the potential for a single molecule of the refrigerant to destroy the ozone layer. Ozone depletion potential odp of a chemical compound is the relative amount of degradation it can cause to the ozone layer. Some manufacturers of refrigerators are developing new models which use hfc 4a or r4a. Fluorocarbons, especially chlorofluorocarbons, became commonplace in the 20th century, but they are being phased out because of their ozone depletion effects.
Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule. Safe use of flammable, toxic and highpressure refrigerants. Refrigerants are regulated as hazardous materials by the us epa and carb, due to their ozone depleting ability and powerful greenhouse gas potential. It mandates that all refrigerants with odp will be phased.
When did it become unlawful to intentionally release class i and class ii refrigerants into the atmosphere. The ozone depletion potential odprh of a gas rh is the relative amount of. Eu has taken the effort to elaborate a table of new substances with ozone depletion potential. Usage of some refrigerating fluids is limited with kyoto protocol 1 due to their contribution to sera gas formation. Indicators for quantitative comparison of the various substancesareodp8ozonedepletionpotentialandgwp9 global warming potential, which are closely related to their atmospheric lifetime alt 10. Products that normally contain ozone depleting substances should be replaced with functionally similar products that contain nonozone depleting substances. Aug 12, 2019 the kigali agreement was created in october 2016, became effective globally on jan. This reduction has largely been driven by the 1987 united nations environment programme unep montreal protocol. Initially, the mp would reduce usage of ozone depleting substances by half, but it later placed bans on substances with significant ozone depletion potential odp. R404a is a ternary refrigerant blend consisting of the hfc r125 fortyfour percent, hfc r143a fiftytwo percent, and hfc r4a four percent.
Measurements of chlorine within the antarctic ozone hole from nasas aura satellite. Global warming potential vs ozone depletion potential. A critical link in protecting climate and the ozone layer. Further it was decided in dec ix24 and x8 to request parties to report to the ozone secretariat on new substances. But through domestic and international action, the ozone layer is healing and should fully recover by about 2065. Indicators for quantitative comparison of the various sub. This transition was a global effort under an international treaty known as the montreal protocol mp that addressed the destructive effects these compounds had on the ozone layer. Download our free whitepaper that busts the myths on refrigerants. Ozone is depleted by chlorinecontaining compounds that reach the upper atmosphere.
Although these refrigerants have no ozone depletion potential, they have a negative impact on global warming when these refrigerants leak to atmosphere during system operation. The less the value of the odp the better the refrigerant is for the ozone layer and therefore the environment. The emission of ozone depleting substances has been damaging the ozone layer. Its gwp global warming potential its odp ozone depleting potential its energy efficiency when used as refrigerant. Refrigerant selection to reduce climate impact edge buildings.
Ozone depletion and global warming potential of thermal. They also have good energy efficiency, but are flammable and can form an explosive mixture with air if a leak occurs. The concept of ozone depletion potential odp is widely used wuebbles et al. The less the value of the odp the better the refrigerant is for the ozone layer and the environment. R111, 2 global warming potential 100 year, ipcc 4th assessment report, 2007. Acknowledgements hfcs, climate protection and the ozone layer 3. In the refrigerant sector two mature technologies, fluorinated refrigerants hfcs with their high global warming potential as well as environmentally friendly natural refriger. A digital copy of this report can be downloaded at unep promotes. Different substances break down ozone more rapidly than others. It breaks down and reacts with ozone molecules in accordance with the equation above repeatedly until a more stable compound is created. Amolea at2 has no ozone depletion potential, has less global warming potential than our existing asahiklin ae3000 series products, is nonflammable, and is energy efficient due to its low latent heat of vaporization.
Odp values are used to provide a simple way to compare the relative ability of various ods to destroy stratospheric ozone. Chlorine interacts with ozone, converting it into oxygen and taking away its beneficial properties. The thermochemical and physical properties of each refrigerant were used to determine. Fellow ashrae mcquay international staunton, virginia usa 1 what is a refrigerant. Refrigerants and their application presented by thomas e. It went into effect in 1987, first targeting cfcs, then hcfcs. Refrigerants used in air conditioners are changing again. A significant reduction in the consumption of ozonedepleting substances ods has been achieved by the eea33 countries since 1986. R427a like other gases such as r407c is a zeotrope. Common refrigerants and their ozone depletion potential odp and global warming potential gwp are indicated below.
Odp is defined as the integrated change in total ozone per unit mass emission of a specific ozonedepleting substance relative to the integrated change in total ozone per unit mass emission of cfc11 wmo, 1995, i. Management of ozone depleting substances refrigerants. Production and consumption of ozonedepleting substances. Two refrigerant alterna tives are predominant for the manufacture of new domestic refrigerators. Many working fluids have been used for such purposes. Pdf the refrigeration and airconditioning industries are important sectors of. Characteristics of some new generation refrigerants with. Substances with high global warming potential gwp are a key concern. Up to two points are awarded where it is demonstrated that hvac refrigerants in use have an ozone depletion potential odp of zero or where no refrigerants are used, as follows. Ozone depletion potential of different refrigerants. Growing demand for refrigeration and airconditioning with diversified applications has led to a continued search. The program looks at overall risks to human health and the environment of existing and new substitutes, publishes lists and promotes the use of acceptable substances. Since the introduction of the montreal protocol, european consumption eea28 in 1986 has fallen from approximately 343 000 ozone. Halogenated hydrocarbons, especially chlorofluorocarbons cfcs, are a major cause of ozone layer depletion because of the amounts of chlorine atoms that are part of their makeup.
Graph showing the ozonedepletion potential odp, or potential damage that each substance could cause to the ozone layer, relative to the chlorofluorocarbon, cfc11. Because cfcs and hcfcs contain chlorine, which has ozone depletion potential odp, the montreal protocol focused on phasing out cfcs and hcfcs. 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. As a result of ozone depletion in the upper atmosphere, m. Explain ozone depleting potential of conventional refer. Hydrocarbon refrigerants are flammable, nontoxic, zero odp ozone depletion potential and very low gwp global applications. 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. Ozone depletion potential an overview sciencedirect topics.
Solomon and albritton, 1992 as a measure of the effectiveness of a given compound in removing ozone, relative to a standard compound, which is taken to be cfc11. 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. By comparing the ozone depletion potential of n 2 o with those of other ozone depleting substances, wang et al. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of. Stratospheric ozone depletion european environment agency.
But we are all part of the problem, simply because many of the products we use every day can release ozone depleting substances into the atmosphere. A viable lowgwp candidate must possess a number of other attributes 6, including zero or very low ozonedepletion potential, chemical stability within the. The higher the number, the more damage a chemical can cause to the ozone layer. Since the introduction of the montreal protocol, european consumption eea28 in 1986 has fallen from approximately 343 000 ozone depleting. Pdf refrigerant types, issues, trends and future options. Low gwp refrigerants can contribute greatly to greenhouse gas mitigation. Zero ozone depletion potential replacement for r22. The use of hydrocarbon refrigerants is becoming increasingly popular due to their low environmental impact and excellent thermodynamic performance. Ozone depleting substances refrigerant reclaim australia. This index is determined through the comparison with the molecule of r12 cfc 1, the maximum potential value of ozone layer destruction. In most cases no timeconsuming circuit rinsing is required. Although these refrigerants have no ozone depletion potential, they have a negative impact on global warming when these refrigerants leak to atmosphere during.
All of the refrigerants use r11 as a datum reference and thus r11 has an odp of 1. 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. Hfc4a has no ozone depletion potential and is nonflammable. Graph showing the ozone depletion potential odp, or potential damage that each substance could cause to the ozone layer, relative to the chlorofluorocarbon, cfc11. Refrigerants containing chlorine or bromine contribute to the breakdown of the ozone layer see figure 5. This is measured by their ozonedepletion potential odp. In order to reduce the depletion of ozone and reverse the climate change effects, the european union legislation 2014 and paris accord 2016 are strongly emphasizing the phasing out of the use of harmful synthetic refrigerants. Ozonedepleting substances ozone layer protection us epa. Ozone depletion potential odpr111 0 i information based on estimated properties. July 1, 1992 which of the following refrigerants have the lowest ozone depletion potential odp. The odp is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of cfc11. Index that characterizes the participation of one molecule of refrigerant in the process of ozone layer destruction.
R22 phaseout timeline 1999 100 50 0 % 1996 cap 100% 65% 25% 10% us eu a5 nations today 6 32. Production and consumption of ozonedepleting substances in. R404a began seeing usage in 1996 after the phase out of cfc r502 due to its ozone depletion potential. Stratospheric ozone depletion and climate change see chapter 8 therefore have common sources. Chlorodifluoromethane r22, for example, has an odp of 0. Potential ozone depletion potential phase out date toxic flammable global warming potential ozone depletion potential phase out date toxic flammable cfc high high 1996 no hfo low none na varies hcfc high medium 2030 no hfo hfc blends medium none na low to none.