Measurements of chlorine within the antarctic ozone hole from nasas aura satellite. The first is that they are not reactive chemically speaking, which means they survive long enough in the atmosphere to drift up into the. The ozone layer in the upper atmosphere absorbs most of the harmful ultravioletb uvb radiations from the sun. Zero ozone depletion potential replacement for r22. Odp ozone depletion potential degree to which a substance can degrade the ozone layer. 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.
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. The odp values are from table 15 of the scientific assessment of ozone depletion, 2002, a report of the world meteorological associations global ozone research and monitoring project. It went into effect in 1987, first targeting cfcs, then hcfcs. Products that normally contain ozone depleting substances should be replaced with functionally similar products that contain nonozone depleting substances. Scientific assessment of ozone depletion, world meteorological organization table 1 evolution of gwp values the gwp values illustrated in table 1 above are based on international scientific assessments and reflect the latest scientific consensus on potential climate impacts at the time of publication of the. Nonozone depleting substances ods do not deplete the earths protective ozone layer. Ozone depletion potential odp and global warming potential. Ozone depleting substances refrigerant reclaim australia. Evidence shows that the main causes of ozone depletion are the releases of manufactured. If the refrigerant is less efficient than r4a or r410a, the lower efficiency chiller will contribute more to global warming through higher energy usage, leading to increased carbon emissions. R404a is a ternary refrigerant blend consisting of the hfc r125 fortyfour percent, hfc r143a fiftytwo percent, and hfc r4a four percent.
But through domestic and international action, the ozone layer is healing and should fully recover by about 2065. The net gwps of halocarbons depend strongly upon the effectiveness of each compound for ozone destruction. Refrigerants containing chlorine or bromine contribute to the breakdown of the ozone layer see figure 5. 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. It is found that hcfcs generally have much lower ozone depletion potential odp. In the 2009 version, they were ea p3 and ea c4 respectively.
One class of potential replacement refrigerants exhibit relatively low gwp but mild flammability i. Pdf ozone depletion potential of different refrigerants. Ozone depletion potential odp of a chemical compound is the relative amount of degradation it can cause to the ozone layer. The hydrogen makes them less stable and therefore less damaging to the ozone layer. Freon refrigerants 4 introduction background chlorodifluoromethane r22 or hcfc22 has been used as a refrigerant in various refrigeration, industrial cooling, air conditioning, and heating applications for over five decades. Cfc11 and cfc12 with the longest atmospheric lifetime and highest ozone depletion potential were phased out first, followed by the hydrochlorofluorocarbons. Which type of refrigerant has the highest ozone depletion potential. Ozone depleting substances ods contain various combinations of the chemical elements chlorine, fluorine, bromine, carbon, and hydrogen and are often described by the general term halocarbons.
The absolute highest gwp on hydrocarbon refrigerants that i could find was twentyfive. Journal of biomimetics, biomaterials and biomedical engineering materials science. R404a began seeing usage in 1996 after the phase out of cfc r502 due to its ozone depletion potential. The third category is alternative cycles that include absorption systems, and use of. However, r410a has a high global warming potential of 2088, higher than that of r22. The dilemma, therefore, is that some refrigerants cause more ozone depletion than others, but the most ozone friendly refrigerants cause more global warming. Environmental management of refrigeration equipment pdf, 151kb. Chlorodifluoromethane r22, for example, has an odp of 0. Stratospheric ozone depletion is a global threat to the balance of nature resulting in a decreasing concentration of ozone particles in the upper atmosphere. The primary disadvantage of r407c is the large temperature glide due to the blend of the specific refrigerants. 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. Calculating ozone depleting potentials odp introduction the number of single component refrigerants with different thermodynamic properties suitable for different types of equipment is limited. Cfcs were replaced with hcfcs, which have lower ozone depletion potential odp, or with.
Chapte r ozone depletion potentials, global warming. Research and development roadmap for nextgeneration low global warming potential refrigerants introduction 9 1 introduction 1. This website addresses stratospheric ozone issues, including the science of ozone depletion, epas regulatory approach to protecting the ozone layer, epaapproved alternatives to ozone depleting substances, and sun safety. Ministry home air ozone depleting substances frequently asked questions frequently asked questions about ozone depleting substances ods in ontario ozone depletion prevention odp cards what is required for the purchase andor handling of refrigerants in ontario. A complete analysis of the relative harms of ozone depletion and global warming is beyond the scope of this report, because the full implications of both anthropogenic effects are not known. Note the trend of the cclf2x series in the table below. 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. Frequently asked questions about ozone depleting substances. The important environmental and safety properties are. The treatment by leed of the environmental impact of hvac. Refrigerants r407c and r407a properties, uses, storage. The first generation of refrigerants included substances such as hydrocarbons, ammonia, and carbon dioxide. Hfcs such as r4a used in positive pressure centrifugal chillers have no ozone depletion potential odp. Global warming potentials, and future chlorine bromine loading.
Refrigerant product information opteon xp10 r5a is a non ozone depleting, low global warming potential gwp hydrofluoroolefin hfo based refrigerant developed to replace r4a in positive displacement, direct expansion, mediumtemperature commercial and industrial chillers, as well as flooded andor centrifugal chillers. It is also a common component in many hfc refrigerant blends and is used. 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. The other hydrocarbons were all between five and zero. Gwp global warming potential degree to which a greenhouse gas ghg traps heat in the atmosphere. Ozone depletion potential an overview sciencedirect topics. Enhanced refrigerant management and leednc v4 ea credit 6. The montreal protocol groups ozone depleting substances ods. 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. Different substances break down ozone more rapidly than others. Like all hcfcs, however, r22 has been shown to deplete the ozone layer. Purpose the purpose of this course is to familiarize you with the background of the fundamental refrigerant management prerequisite and enhanced refrigerant management credit previously called the ozone protection credit in the. The environmental challenge for over twenty years, the hydrochlorofluorocarbon hcfc r22 has been an extremely useful refrigerant gas across a wide range of air conditioning and refrigeration applications.
According to the montreal protocol, the odp of refrigerants should be zero, i. R427a like other gases such as r407c is a zeotrope. Ozonedepleting substances ozone layer protection us epa. Indicators for quantitative comparison of the various substancesareodp8ozonedepletionpotentialandgwp9 global warming potential, which are closely related to their atmospheric lifetime alt 10. Odp defined the odp, or ozone depletion potential, is the potential for a single molecule of the refrigerant to destroy the ozone layer. Except for a few hcfcs already in use in canada mainly used as refrigerants most hcfcs have been developed for use as transitional chemicals to replace the more damaging ozone depleting substances, mainly cfcs. R111, 2 global warming potential 100 year, ipcc 4th assessment report, 2007. Gwps including indirect effects of ozone depletion have been estimated fo r a variety of halocarbons cfcs, halons, hcfcs, etc. The concept of ozone depletion potential odp is widely used wuebbles et al. 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. Stratospheric ozone depletion and hvac refrigerants. Although these refrigerants have zero ozone depletion potential odp and minimum global warming impact due to direct emissions but there are safety and environmental factors associated with them that would limit their widespread use as refrigerants.
Volkmar hasse, gtz proklima, germany preface volkmar hasse, gtz proklima i. Pdf refrigerant types, issues, trends and future options. They have a very low or zero global warming potential and zero ozone depletion potential. Which of the following refrigerants contains chlorine. Enhanced refrigerant management and leednc v4 ea credit 6 john m. Add r427a, with an initial charge of 95% of the original weight. Opteon xp10 r5a is a nonozone depleting, low global warming potential gwp hydrofluoroolefin hfo based refrigerant developed to replace r4a in positive displacement, direct expansion, mediumtemperature commercial and industrial chillers, as well as flooded andor centrifugal chillers. Difluoromethane constitutes a significant portion in both of these gaseous hence its. Odp is ozone depletion potential of with re ference to cfc r11 as 1. These substances are effective ozone depleters for two reasons. On top of that there is the direct global warming potential gwp due to refrigerant emission.
Global warming potential vs ozone depletion potential. Product information sorted by product type and name type product r number. Natural refrigerants sustainable ozone and climatefriendly alternatives to hcfcs introduction dr. Ozone depletion potential odp and global warming potential gwp ozone depletion potential odp the montreal protocol on substances that deplete the ozone layer and it amendments control the phaseout of ozone depleting substance ods production and use1. This is measured by their ozone depletion potential odp. Hcfcs have less ozone depleting potential than cfcs and have been useful as an interim. Growing demand for refrigeration and airconditioning with diversified applications has led to a continued search. The problem of global warming must be considered while focus is fixed upon the problem of ozone depletion. After a series of rigorous meetings and negotiations, the. 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. Calculation of global warming potential gwp v alues of refrigerants is a complex issue. As a result of the montreal protocol 1987 to phase out ozone depletion gaseous, the r410a and r407c are refrigerant blends that are used to replace ozone depletion refrigerants such as r22 as both of these gaseous have zero odp ozone depletion potential.
However, the choice of alternative refrigerants is domestic issues involving recycling or disposal of refrigerants. The low ozone depletion potential of r22 compared to cfc11 chlorofluorocarbon 11 and cfc12 and its excellent refrigerant properties have helped facilitate the transition away from cfcs. When these substances reach the upper atmosphere, they create chemical reactions which cause the ozone molecules in the atmosphere to break down. Refrigerant types, issues, trends and future options. Hydrocarbon refrigerants have zero ozone depletion potential and have a very low global warming potential. Indicators for quantitative comparison of the various sub. Ozone depletion potential is measured relative to cfc11 and it represents the. Ozone depletion, montreal protocol and kigali agreement ozone depletion ozone o 3 forms a layer in the stratosphere, between 10 to 50 km above the earth, thinner in the tropics around the equator and denser towards the poles. Risk assessment of refrigeration systems using a2l flammable. Policylegislation on fgases and alternatives two environmental frameworks one goal the montreal protocol and the kyoto protocol. Which of the following refrigerants has the lowest global warming potential. 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 ozone depleting refrigerants like r22 are phased out.
R600a gwp 3 which gas is used as the baseline measurement for global warming potential. This is a relative indication of the effect of the substance on breaking down 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. In most cases no timeconsuming circuit rinsing is required. The ozone depletion is a global problem like global warming. The regulation for the management of high global warming potential refrigerants for stationary sources carb. Global warming potential gwp is a measure of how much a given mass of a gas contributes to global. Environmental impact of the refrigeration and air conditioning sectors refrigerants refrigerants pose a threat to the environment because of their ozone depletion potential odp and global warming potential gwp. Hfcs and natural refrigerants are both developed to alternate cfcshcfcs. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the. The low ozone depletion potential of r22 compared to cfc11 chlorofluorocarbon 11 and cfc12. Halocarbon potential contributions to ozone depletion and global warming exhibit 2 provides odps for the class i and class ii odss.
Linde strongly advocates the use of refrigerant gases with zero ozone depletion potential and fully supports the phase out of hcfcs. Table 1 gives an overview of the different groups of refrigerants. Pdf refrigeration and airconditioning play a vital role in domestic and industrial applications. The following is a list of refrigerants with their typeprefix, ashrae designated numbers, iupac chemical name, molecular formula, cas registry number blend name, atmospheric lifetime in years, semiempirical ozone depletion potential, net global warming potential over a 100year time horizon, occupational exposure limitpermissible exposure. Refrigerant gases containing chlorine or bromine have a high ozone depletion potential odp and damage the planets ozone layer. All of the refrigerants use r11 as a calibration and thus r11 has an odp of 1. Pdf ozone depletion potential of different refrigerants and. Ozone depletion potential of different refrigerants and their solution. The compatibility with the environment has become an essential criterion when a new refrigerant is selected to alternate cfcshcfcs.
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