Refrigerants for Residential and Commercial AirConditioning ApplicationsOctober 2008

1

Executive summary 2

Introduction and background 3

Environmental drivers 4

Regulatory update 8

Criteria for refrigerant selection 11

Transitional refrigerants (HCFCs) 12

Chlorine-free refrigerants (HFCs) 13

Halogen-free refrigerants 18

Lubricants 20

Responsible-use principles 22

Future direction 23

Glossary of terms 24

Appendix 25

Contributors 26

Table of contents

2

The topic of potential future transitions to only naturalrefrigerants, such as propane and carbon dioxide, is mostly driven by anti-HFC regulations in Europe.Research data reveals that HFCs provide equal orsuperior environmental characteristics to these proposednatural refrigerants at lower cost.

The global sustainability of HFCs like R-410A requiresa focus by the HVAC industry on the real environmentalissues of refrigerant containment and energy efficiency.By committing to the design of more energy-efficientsystems using these refrigerants, the industry willsignificantly improve the environmental impact of air conditioning products.

The need to transition from HCFCs to HFCs is now. R-410A will completely replace R-22 in new equipmentby 2010 and the Environmental Protection Agency (EPA)forecasts shortages of R-22 for service of oldersystems after 2014.

Emerson Climate Technologies has committed itselfto providing solutions that improve human comfort,safeguard food and protect the environment. We are confident in our ever-developing solutions thatprovide efficient residential and commercial airconditioning, without compromising our globalenvironment. At Emerson responsible environmentalstewardship is an integral part of sound businesspolicy and practice. The following paper discusses the factors that we feel are most important formeeting this challenge.

The phase-out of chlorofluorocarbons (CFCrefrigerants) for air conditioning systems in the early-to-mid 1990s has had a significant and positiveeffect on the environment, significantly reducingharmful chlorine in the atmosphere and is credited as a major factor in the improvement of the ozonedepletion problem.

The success of the CFC phase-out, along withincreasing environmental concerns from regulatorsand policymakers, continues to drive new, strictermandates regarding use of refrigerants. The nextmandate the heating, ventilating and air conditioning(HVAC) industry now faces is a phase-out of allhydrochlorofluorocarbons (HCFC refrigerants) in new equipment by 2010, including the popular airconditioning refrigerant, R-22. With the phase-out of R-22 system manufacturers are forced to choose newHFC refrigerants that eliminate the harmful chlorine,while offering the best system efficiency possible.

New refrigerant choices must also be safe to humans,environmentally friendly and provide excellentperformance benefits. Hydrofluorocarbons (HFCs), like R-410A, are global warming gases, but due toinsignificantly low emissions in air conditioning systems,the indirect global warming impact, which relates to the amount of carbon dioxide produced to power the system, is much more important than the directglobal warming potential of the refrigerant itself. All of the HFCs that have been evaluated are non-ozone-depleting, nonflammable, recyclable andenergy-efficient refrigerants of low toxicity that aresafe and cost-effective.

Emerson Climate Technologies has identified aspecific HFC, R-410A, as the best long-term solutionfor residential and light commercial air-conditioningdue to its combination of high-efficiencyperformance in air conditioning systems and directGWP value close to R-22. System manufacturers havehad good success with R-410A because of its energy-efficient properties and ease of use in their systemsand components are now widely available fordesigning efficient R-410A systems.

DISCLAIMERUse only refrigerants and lubricants approved by and in the mannerprescribed by Emerson. In some circumstances nonapproved refrigerantsand lubricants may be dangerous and could cause fires, explosions orelectrical shorting. For more information contact Emerson and your originalequipment manufacturer (OEM).

Executive summary

Scientific data support the hypothesis that chlorinefrom refrigerants is involved in the depletion of theEarth’s ozone layer. The air conditioning industry hassupported global efforts to protect the environment by introducing non-chlorine-containing refrigerants.The Montreal Protocol, established in 1987 and revisedsubsequently, provides guidelines for individual countrylegislation, setting appropriate timetables for thephaseout of chlorine-containing refrigerants. Atpresent, 191 nations have become party to theMontreal Protocol.

The effort began with an emphasis on reducing CFCrefrigerants. The efforts of the late 1980s and early1990s centered on the elimination of CFCs, primarilyused in foam blowing, cleaning and air conditioningapplications. By the end of 1995, the production ofCFCs ceased in developed countries, including the U.S.,and they are no longer used in new equipment today.These actions have proven to significantly reduceatmospheric chlorine and are starting to reduce ozonedepletion.

In 1997, the Kyoto Protocol, signed and ratified bymany nations around the world, focused attention onthe impact of human activity on climate change. Asa result, there is now increased attention on globalwarming. While the Kyoto Protocol does not apply tothe United States, our industry has worked to reducethe impact of refrigerants on climate change throughthe use of higher-efficiency refrigerants and systemdesigns.

In 1997, the Air-Conditioning and Refrigeration Institute(ARI) completed a major international testing program,entitled the Alternative Refrigerants Evaluation Program(AREP). The AREP report indicates that there are severalsuitable HFC replacements for hydrochlorofluorocarbon(HCFC) R-22. In the U.S. and Europe, these HFCreplacements are already being widely used. Whilesome of these replacement refrigerants have differentoperating characteristics than HCFC R-22, they alleliminate chlorine and potential ozone depletion,leaving global warming as the focus for futureregulations and control.

Introduction and background

3

4

1 yosemite.epa.gov/oar/GlobalWarming.nsf/content/climate.html

The need to protect the Earth’s ozone has resulted innew government regulations and the creation of HFCrefrigerants. Since HFCs are chlorine free, they will notdamage the ozone layer.

Global warming

According to the National Academy of Scientists, thetemperature of the Earth’s surface has risen by aboutone degree Fahrenheit (0.5 Kelvin) in the past century.1

There is evidence that suggests that much of thewarming during the last 50 years is due to greenhousegases, many of which are the byproduct of humanactivities. Greenhouse gases include water vapor,carbon dioxide, methane and nitrous oxide, as well assome refrigerants. When these gases build up in theatmosphere, they trap heat. The natural greenhouseeffect is necessary for life on Earth, but scientistsbelieve that too much greenhouse effect will lead toglobal warming. Figure 1 shows the mechanism of thisglobal warming process.

There are two factors important to the discussion of theenvironmental impact of refrigerants: ozone depletionand global warming.

Ozone depletion

The ozone layer surrounding the Earth is a reactive formof oxygen 25 miles above the surface. It is essential forplanetary life, as it filters out dangerous ultraviolet lightrays from the sun. Depleted ozone allows higher levelsof ultraviolet light to reach the surface, negativelyaffecting the quality of human, plant, animal andmarine life.

Enough scientific data have been collected to clearlyverify that there has been depletion of the Earth’s ozonelayer. The data also verify that a major contribution toozone depletion is chlorine, much of which has comefrom the CFCs used in refrigerants and cleaning agents.

Research has shown that even the chlorine found in R-22 refrigerants can be harmful to the ozone layer.

Environmental drivers

The Greenhouse EffectFigure 1

Solar radiation passes through theclear atmosphere.

Most radiation is absorbed by the Earth’s surface and warms it.

Some solar radiation is reflected by the Earth and the atmosphere.

Some of the infrared radiation passes through the atmosphere, andsome is absorbed and re-emitted in all directions by greenhouse gas molecules. The effect of this is to warm the Earth’s surface andlower atmosphere.

Infrared radiation is emitted from the Earth’s surface.

5

The air conditioning industry developed TEWI as a wayto measure the impact of various activities on globalwarming. TEWI is widely accepted as the best measureof global warming, because it considers not only thedirect GWP, but also the sizable indirect global warmingresulting from the CO2 produced by fossil-fuel energy,as seen in Figure 2. This global warming calculationincludes the effects of system efficiency and the sourceof the electricity (coal, nuclear, hydroelectric, etc.), aswell as the direct effect of the refrigerant when itescapes into the atmosphere. The actual number variesaccording to the leakage rate and type of power used.Higher energy efficiency of some refrigerants cansignificantly reduce the indirect effect and offset asomewhat higher direct GWP.

Carbon dioxide (CO2) is one of the major greenhousegases. The natural decomposition of organic materialsis the primary generator of CO2.

The combustion of fossil fuels also adds CO2 to theatmosphere. Fossil fuels are used in power plantsaround the world to produce electricity for vital socialneeds. More than 22 billion tons of carbon dioxide areproduced worldwide each year,2 generated from fossilfuels, such as natural gas, oil and coal. In comparison,total annual HFC production globally is less than 0.001percent of this figure. It is estimated that HFCs willcontribute no more than three percent of greenhousegas emissions by 2050. Energy-efficient air conditioningequipment reduces energy consumption even further,thus reducing energy-related carbon dioxide emissions.

Total Equivalent Warming Impact (TEWI)Global Warming Potential (GWP) is a direct measure ofglobal warming that considers only the direct effect ofthe refrigerant as a greenhouse gas when it escapesinto the atmosphere. Essentially, all alternatives to R-12and R-502 have substantially less direct GWP and are,therefore, considered a move in the right direction. As a result, refrigerants with a GWP of less than 4,000have generally been accepted; however, some Europeancountries are using 2,000 as a maximum GWP(reference GWP for R-11 = 4,000).3

2 National Council for Science and the Environment

3 Global Warming Potential (GWP) is a measure of how much a given mass ofgreenhouse gas is estimated to contribute to global warming. It is a relativescale that compares the gas in question to that of the same mass of carbondioxide, whose GWP is 1.0. GWP is based on a number of factors, includingthe radiation efficiency (heat-absorbing ability) of each gas relative to that of

carbon dioxide, as well as the decay rate of each gas (the amount removedfrom the atmosphere over a given number of years) relative to that ofcarbon dioxide (1.0). The Intergovernmental Panel on Climate Change(IPCC) provides the generally accepted values for GWP, which changedslightly between 1996 and 2001.

Figure 2

Global Warming Impact

Figure 3

Typical AC Total Equivalent Warming Impact (TEWI)

6

unknowns included either inaccurately or not at all inthe models, a lot of room for doubt remains. If themodels are accurate and the warming is caused by CO2 and other man-made chemicals, the long-termtemperature rise will raise the sea level dramatically and change the world’s climate, unless the process isreversed now.

As a result of this scientific thinking, many lawmakersand regulators around the world agree that the onlysafe action to take is to significantly reduce or eliminatethe production of greenhouse gases as soon as possible.In order to reduce the increase in greenhouse warming,the following gases must be capped and reduced:carbon dioxide (CO2), methane (CH4), nitrous oxide(N2O), fluorocarbons (PFCs), sulphur hexafluoride(SF6), HFCs and CFCs.

Carbon dioxide is by far the most significant, as can be seen in Figure 4. CO2 is produced primarily by thecombustion of fossil fuels during the generation ofenergy to power transportation and electric generation.To achieve the needed CO2 reduction from what ispredicted as shown in Figure 4, a dramatic changein energy consumption from fossil-fuel combustion must be realized.

Direct global warming is an issue only if the refrigerantleaks or is released from the air conditioning system;thus, refrigerant containment in the system is the keyto reducing the direct global warming effect. This isaccomplished through system designs that reduce thestored volume of refrigerant, the quick repair of all leaksand the recovery of refrigerant during service operations.

Indirect global warming is a function of the efficiency ofany piece of equipment. In an air conditioning system,the compressor efficiency, system design,thermodynamic transport and heat-transfer propertiesof the refrigerant affect the overall energy efficiency ofthe equipment. Indirect global warming takes intoaccount the energy efficiency, as well as the powersource. Electrical generation can come from fossil fuels,hydropower or nuclear power. The implication is that aless efficient system uses more electricity, and thus hasa higher TEWI (see Figure 3).

Many in the scientific community agree that there isevidence that the Earth is warming; however, it is notyet fully known whether this is the result of normalclimate variations or the result of greenhouse warmingfrom man-made compounds in the atmosphere,specifically CO2. Computer models point to thegreenhouse effect, but with all the variables and possible

Figure 4

Relative Projected Contributions of Greenhouse Gases to GWP

7

which can be most effectively dealt with through theuse of higher-efficiency refrigerants and the design of higher-efficiency systems – can have a far greaterimpact than direct global warming.

As we consider the refrigerants available tomanufacturers and the potential global warmingimpact of each, we believe it is likely that mostresidential and commercial air conditioning applicationswill eventually move to one HFC option, R-410A. Both commercial and residential system manufacturersare currently focused on developing optimized R-410Asystems (see Figure 5). The efficiency, performanceand cost advantages of this refrigerant outweigh thedisadvantages associated with higher pressures anddirect GWP.

Emerson Climate Technologies firmly supports the useof TEWI and expects that this measurement tool willbecome the representative criterion in selecting futurerefrigerants. By selecting the right refrigerant andoptimizing the energy efficiency of air conditioningequipment, greenhouse gas emissions will be minimized.

In dealing with the changing refrigerant environment,Emerson has adhered to a strategy that permits us toserve our markets with products that provide provenperformance, demonstrated reliability and minimumrisk, while moving as rapidly as possible to chlorine-free alternatives.

TEWI and refrigerantsThe issue of global warming is a significantconsideration in the selection of future refrigerants.Some refrigerants have a higher direct GWP thanothers; however, direct global warming alone can be misleading in understanding the overall effect ofvarious refrigerant alternatives. TEWI helps to assess the climate-change impact fairly, as it accounts for boththe direct (refrigerant emissions) and indirect (systempower consumption/efficiency) effects in evaluatingglobal warming. Today’s HFC refrigerants appear to bevery good options, when comparing the total globalwarming impact to that of halogen-free refrigerants.

TEWI highlights the importance of careful considerationof overall system efficiency over the life of the product.As shown in Figure 3, indirect global warming – that

Figure 5

Projected U.S. Air Conditioning Trends to 100 Tons

8

While CFC usage has declined significantly, developingcountries worldwide are still using these refrigerants innew equipment and for service and will continue to do so until CFCs are phased out of production generally in 2010. Additionally, HCFCs continue to support airconditioning and refrigeration equipment in a majority ofapplications. Regulations have been developed to manageconsumption of these refrigerants as the world movestoward full adoption of non-chlorine-containingcompounds.

Montreal Protocol (1987)4

The Montreal Protocol, developed in 1987 in Montreal,Canada, was adopted by all developed countries and has

HCFC Phaseout TimelineFigure 6

Regulatory updateresulted in the phaseout of CFCs. It also placed an initialcap on HCFC production at 1996 levels. As shown inFigure 6, allowable HCFC production levels continue toreduce with time, with the next significant reductionplanned in 2010.

The Montreal Protocol supports the use of HCFCs to aid in the transition from CFCs; however, HCFCconsumption will be limited, relative to historic usage of CFC and HCFC on an ozone-depletion weighted basis, during the transition. The EPA has establishedU.S. regulations, which control future use of HCFCs,according to a schedule that both the agency andindustry believe is appropriate.

4 The Montreal Protocol on Substances that Deplete the Ozone Layer is alandmark international agreement designed to protect the stratosphericozone layer. The treaty was signed originally in 1987 and amendedsubstantially in 1990 and 1992.

9

Kyoto Protocol (established 1997) The Kyoto Protocol was established in 1997, in responseto increased global warming concerns. Per thisprotocol, developed countries are challenged withreducing greenhouse gases by an average of 5.23percent from 1990 levels between the years 2008 and2012. The protocol focuses on six gases, which it viewsas being considered and controlled as a total package.These gases include CO2, CH4, N2O, HFCs, PFCs and SF6.

European F-Gas Directive (established 2001)5

In the European Union, legislation aimed at containmentof HFC refrigerants has gone into effect, with mostprovisions becoming effective July 2007. Known as the“F-Gas Directive,” it proposes to minimize the emissionsof fluorinated gases by requiring leakage inspections,leak-detection systems, recovery, and training andcertification. See EPEEGlobal.org for further details.

Air conditioning efficiency standardsAt the same time that the air conditioning industry isdealing with refrigerant transitions and the 2010phaseout of R-22, another major trend is occurring.Increased energy-efficiency standards are already inplace for residential systems, and new energy standardsfor commercial systems will apply in 2010.

The Energy Policy Act of 2005 established federalenergy-efficiency standards for commercial airconditioning systems that are 10 percent above current American Society of Heating, Refrigerating & Air Conditioning Engineers (ASHRAE) 90.1 minimums.These standards become effective January 1, 2010,coinciding with the phaseout of HCFC R-22 for newsystems. Higher state or regional standards mayemerge, pushing minimum efficiency levels evenhigher. Most commercial system manufacturers areredesigning systems for both R-410A and higherefficiency. Most current commercial products will beobsolete in 2010.

EPA schedule (established 1996)The EPA is continually monitoring the U.S. compliancewith the Montreal Protocol and has even developeda schedule to monitor progress toward the totalphaseout of HCFCs. The United States Clean Air Actestablished regulations for the implementation of thisphaseout. For example, by 2010 there will be noproduction and no importing of R-22, except for use in equipment manufactured before January 1, 2010.

Below is the HCFC phaseout schedule developed by theU.S. EPA:

January 1, 2004In accordance with the terms of the Montreal Protocol, theamount of all HCFCs that can be produced nationwidewas reduced by 35 percent by 2004. In order to achievethis goal, the U.S. ceased production of HCFC-141b, the most ozone-damaging of this class of chemicals, onJanuary 1, 2003. This production ban greatly reducednationwide use of HCFCs as a group. The 2004 deadlinehad a minimal effect on R-22 supplies.

January 1, 2010In 2010 and beyond, chemical manufacturers may stillproduce R-22 to service existing equipment, but not foruse in new equipment. Equipment manufacturers mustnot produce new systems utilizing R-22.

January 1, 2020Use of existing refrigerant, including refrigerant that hasbeen recovered and recycled, will be allowed beyond2020 to service existing systems, but chemicalmanufacturers will no longer be able to produce R-22 to service existing systems.

5 The European Partnership for Energy and Environment, EPEEGlobal.org

10

Other regulations Refrigerant decisions are also impacted by otherregulations related to product design andapplication. For example, Underwriters Laboratories,Inc. (UL) revised its test procedures and methods toevaluate refrigerants within air conditioning systems,in response to the newer HFC alternatives.6 In Europe,refrigerant choices are also impacted by commercialincentives, such as refrigerant taxes, depending onGWP and energy-efficiency certification schemes.

It is important for users to continuously monitor andunderstand the impact of all of the various legislativeactions to our industry.

Types of refrigerants In the air conditioning industry, virtually all of therefrigerant experience has been limited to single-component (“pure”) refrigerants; however, as wesearch for acceptable replacements for thesecompounds, refrigerant manufacturers have beenunsuccessful in developing single-componentreplacements that meet all of the required or highlydesirable characteristics for a widely used refrigerant.These requirements include:

• Environmental acceptability

• Chemical stability

• Materials compatibility

• Refrigeration-cycle performance

• Adherence to nonflammable and nontoxic guidelines, per UL

• Boiling point

6 The scope of UL Standard 2182.1 contains test procedures and methods to evaluate refrigerants and mark their containers according to the extentof the refrigerants’ flammability.

11

Since a near-azeotrope is still a zeotrope, thecomposition of the vapor and liquid will be differentwhen both liquid and vapor are present, but to a small extent. If a leak occurs in this region and onlyvapor leaks out, there can be a small change in thecomposition of the refrigerant left in the system.

Since the composition of the liquid and vapor of azeotrope (and near-azeotrope) can be different, it isimportant to charge a system with these types ofrefrigerants with liquid leaving the cylinder. If vapor is charged from the cylinder, the composition of therefrigerant in the system may not be the same as thatin the cylinder, because of the fractionation10 of therefrigerant in the cylinder as vapor alone is removed.Refer to refrigerant manufacturers’ guidelines forfurther details.

Additional information regarding pure compounds,azeotropes, zeotropes and near-azeotropes can befound at EmersonClimate.com.

Evaluation of refrigerant alternatives Established by ARI, AREP was directed by anexecutive committee comprised of senior executivesfrom ARI member companies and was focusedprimarily on identifying possible alternatives to R-22 and R-502 refrigerants. As part of the program,tests were conducted with 19 refrigerants identifiedas potential replacements for R-22. Individual testreports issued included compressor calorimeter,system drop-in, heat transfer and software-optimizedsystem tests for most of these refrigerants.

AREP also tested many types of compressors,including reciprocating, rotary, screw and scrollcompressors. In addition, system performance wasevaluated across a range of applications, includingsplit-system heat pumps, both air- and water-cooledpackaged heat pumps, window units and condensingunits. More than 180 AREP reports were approvedand released to the public when the committeecompleted its testing in 1997.

Many of the R-22 refrigerant replacements underconsideration are not pure, but instead areazeotropes,7 zeotropes8 or near-azeotropes,9 or of two or more compounds. Fortunately, the airconditioning industry has considerable experiencewith each type.

A mixture’s components are chosen based on the finalcharacteristics desired. These characteristics couldinclude vapor pressure, transport properties, lubricantand material compatibility, thermodynamicperformance, cost, flammability, toxicity, stability andenvironmental properties. The proportions of the components are chosen based on the exactcharacteristics desired in the final product.

Behavior of mixtures When an azeotrope, near-azeotrope or zeotrope is inthe pure liquid or pure vapor state, the composition istotally mixed, and all properties are uniform throughout;however, when both liquid and vapor are present(such as in the evaporator, condenser or perhapsreceiver), a mixture’s behavior depends upon whetherit is an azeotrope or zeotrope.

The percentage composition of the liquid and vaporof an azeotrope will always be virtually the same whenboth liquid and vapor are present. If a leak occurs,there will not be a substantial change in compositionof the refrigerant left in the system.

The composition of the vapor and liquid of a zeotropeis different when both liquid and vapor are present. Ifa leak occurs in this region of a system and only vaporleaks out, there can be a change in the composition ofthe refrigerant left in the system. Also, if the systemuses a flooded evaporator or multiple evaporators,the composition of the liquid can be substantiallydifferent from the vapor, resulting in changes in thecirculating refrigerant.

Criteria for refrigerant selection

7 Azeotrope: A blend that, when used in refrigeration cycles, does not change volumetric composition or saturation temperature appreciably as it evaporates (boils) or condenses at constant pressure.

8 Zeotrope: A blend that, when used in refrigeration cycles, changesvolumetric composition and saturation temperatures to varying extents as it evaporates (boils) or condenses at constant pressure.

9 Near-azeotrope: A zeotropic blend with a small temperature andcomposition glide over the application range and no significant effect on system performance, operation and safety.

10Fractionation: A change in the composition of a refrigerant blend by preferential evaporation of the more volatile component(s) orcondensation of the less volatile component(s).

12

Climate Technologies does not approve of the use of flammable refrigerants in any of its compressors.

Toxicity – During the course of the transition fromHCFCs and CFCs to HFCs, some countries haveexplored and/or applied toxic refrigerant options,such as ammonia. These alternatives may offersystem performance benefits, but they can also behighly dangerous. It is the view of Emerson thatrefrigerant options like ammonia should never beused, especially considering that HFCs can deliver the equivalent or better efficiency and overallperformance. The major refrigerant manufacturers,equipment manufacturers and safety-standard-setting agencies, such as UL and ASHRAE, haveextensively studied and then rated the safety aspectsof proposed new refrigerants, according to each of the factors listed above. The intent is to use onlyrefrigerants that are at least as safe as those beingreplaced.

Transitional refrigerants (HCFCs)R-22 has been applied successfully in air conditioningsystems; however, R-22 is an HCFC that is currentlybeing phased out as part of the Montreal Protocol.Phaseout dates for the production of R-22 vary bycountry, but in the U.S. and Canada, new equipmentusing R-22 can no longer be manufactured after2010. Although refrigerant manufacturers believethat an adequate supply of R-22 will be available untilthat time, the EPA predicts the significant potentialfor R-22 shortages in the U.S. after 2014.

In Europe, this transition has already taken place, andHFC refrigerants have become standard for new airconditioning systems.

Of the options identified, several HFC refrigerantshave emerged as candidates for R-22 replacement.These HFC alternatives were confirmed as viableoptions through the AREP studies. Figure 7 lists thecharacteristics of these alternatives. A summary ofthe advantages and disadvantages of each alternativeis discussed in the following sections.

SafetyAs the air conditioning industry moves away from the relatively few CFC and HCFC refrigerants still incirculation, the issue of safety naturally arises. Ofcourse, safety of new refrigerants is paramount whenconsidering which HFC refrigerant to adopt.

Air conditioning safety issues typically fall into fourmajor areas, including:

Pressure – Virtually all of the new refrigerants operateat a higher pressure than the refrigerants they replace. Insome cases the pressure can be substantially higher,which means that the refrigerant can be used only inequipment designed to use it and not as a retrofitrefrigerant.

Material compatibility – The primary safety concernhere is with deterioration of materials, such as motorinsulation, which can lead to electrical shorts, andseals, which can result in leaks.

Flammability – Leakage of a flammable refrigerantcould result in fire or explosions. In addition, many of the new refrigerants are zeotropes, which canchange composition under certain leakage scenarios.Consequently, it is important to completely understandthe flammability of the refrigerant blend, as well aswhat it can change into under all conditions. Usingflammable refrigerants exposes individuals and theenvironment to unnecessary hazards, and Emerson

Source: United Nations Environment Program (UNEP) www.ipcc.ch/index.htm

13

Chlorine-free refrigerants (HFCs)• Service procedures for equipment should remain

simple. The utilization of the refrigerants withrespect to fractionation of blends must notrequire unreasonable service procedures.

Most of the currently proposed long-term refrigerantsare HFCs. The polarity of HFC refrigerants makesthem immiscible with mineral oils. As a result, HFCrefrigerants must be used with polyol ester oil. This is discussed in detail in the “Lubricants” section ofthis report.

HFCsHFCs, or hydrofluorocarbons, are chemicals used inair conditioning applications. They are nonflammable,recyclable, energy-efficient refrigerants of low toxicitythat are being used safely throughout the world.HFCs were developed by the chemical industry asalternatives to ozone-depleting CFCs.

The Technical and Economic Assessment Panel(TEAP) of the Montreal Protocol on Substances thatDeplete the Ozone Layer reported in 1999 that HFCsare critical to the safe and cost-effective phaseout of CFCs and HCFCs and are essential substitutes forthese products. Likewise, HFCs are necessary bothtechnically and economically for the phaseout ofHCFCs in developing – as well as developed –countries. As replacements for less energy-efficient,older equipment, HFC systems conserve energy andreduce the generation of global warming gases atelectric power plants. These systems are being usedin accordance with responsible-use principles, whichrange from recovery and reuse of HFCs to design ofHFC-producing plants, with the goal of minimizingemissions and maximizing energy efficiency.

Substituting HFCs for CFCs has actually reduced theimpact of greenhouse gas emissions, as HFCs reducetotal greenhouse gas release. Projections show thatby 2050, HFC emissions will account for less than two percent of potential future contributions for allgreenhouse gases, as identified in the Kyoto Protocol.12

The selection and approval of acceptable long-termrefrigerants is a complex and time-consuming task.Many factors must be taken into consideration. Theever-shifting legislative and regulatory environment,the phaseout of CFCs and HCFCs, the availability of alternate refrigerants and numerous other factors arejust a few of the issues that must be taken into account.

Based on these factors, Emerson has cited the following key criteria for evaluating andapproving HFC refrigerants for use in EmersonClimate Technologies™ products:

• Global warming should be reviewed, based on theTEWI approach; therefore, the combined directglobal warming and indirect global warming,which varies with energy efficiency, should be less than the refrigerants being replaced.

• Safety must be maintained. New refrigerantsshould be nontoxic, with a Threshold Limit Value(TLV) minus Time-Weighted Average (TWA)11

equal to 400 parts per million (ppm), andnonflammable. If they are not, proper steps must be taken to ensure that the refrigerants areproperly used in equipment and facilities designedto provide adequate safety protection. Maximumsystem pressures must be no greater than currentacceptable limits for retrofit applications.Emerson approves only the use of refrigerantsthat meet UL standards. This currently does notinclude hydrocarbons, such as propane (R-290)and isobutane (R-600a). See Emerson ClimateTechnologies, Inc. Accepted Refrigerants/Lubricants (form 93-11).

• Material compatibility between the new refrigerants,lubricants and materials of construction incompressor and system components must bemaintained.

• It is highly desirable to have a single lubricantsolution that works with all of the alternativerefrigerants, including both HFC and HCFC retrofitchemicals. A single lubricant that works with all of the approved chemicals makes the service andlong-term refrigerant strategies easier to implement.

11 TLV minus TWA presents a standard for limiting worker exposure to airborne contaminants. These standards provide the maximumconcentration in air at which it is believed that a particular substance will not produce adverse health effects with repeated daily exposure. They are expressed either as parts per million (ppm) or milligrams per cubicmeter (mg/m3).

12 The Alliance for Responsible Atmospheric Policy, www.arap.org/print/docs/responsible-use.html

One benefit of the new HFC refrigerants is thatseveral of them have demonstrated better efficiencyin the equipment in which they are used, as comparedto the old refrigerants that they replace. In addition,some of the new refrigerants have lower compressor-discharge temperatures, which should help improvethe compressor’s reliability and durability.

In summing up the status of HFC refrigerants,virtually all of the experience to date has beenpositive. Many system manufacturers have convertedtheir products to HFCs, which seem to be wellreceived by their customers. The viability of the newrefrigerants has been proven by several years’ historyof successful operation in a wide variety of systems.

MixturesAs mentioned earlier in this paper, refrigerantmanufacturers have been unsuccessful in developingsingle-component, high-pressure alternatives to CFCsthat have zero-ozone-depletion potential, adequateperformance, good reliability and safety. Consequently,the possibility of using mixtures (also called blends,azeotropes, near-azeotropes and zeotropes) hasgained increased attention.

Mixtures have both advantages and disadvantages,when compared to pure substances. Mixtures allowthe advantage of tailoring the final refrigerantcharacteristics for superior efficiency, performanceand reliability. Disadvantages of zeotropic mixturesinclude the following:

Temperature glide – Because the composition of azeotrope alters during a phase change, there is aslight change in evaporating and condensingtemperature at constant pressure. This phenomenonis known as “glide.” Most zeotropic mixtures underconsideration exhibit low glide. The magnitude ofthis phenomenon is a little different from similareffects seen with single-component refrigerants, dueto normal pressure drop within the heat exchanger.As a result, little or no effect on system performanceis expected.

An independent third-party report by Arthur D. Little,Inc. released in 2002 analyzed the cost savingsassociated with the use of HFCs. Not only do HFCsprovide the most cost-effective combination ofsuperior environmental performance and safety, butthey also provide significant cost savings in the rangeof $15 billion to $35 billion, compared to poor-performing and less safe alternatives, such ashydrocarbons.

Depending on the country of use, HFC emissionsmanagement is being conducted through mandatoryrecovery and nonregulatory means, voluntarymeasures and industry-government partnerships.The latter involves engaging jointly in research,communication and other activities, to find newtechnologies, designs and processes to manage HFC emissions and to enhance overall product energy efficiency.

HFCs are included among the Kyoto Protocol’s sixgreenhouse gases, and it is believed that they shouldnot be singled out for regulation or restriction.Instead, HFC emissions should be considered only aspart of a comprehensive climate-change plan thatfully considers collective emissions reductions of allgreenhouse gases.

The HFCs and equipment being produced for airconditioning appear to be satisfactory for theseapplications; however, there are several areas inwhich they differ from the refrigerants they arereplacing:

• They require the use of polyol ester (POE) oilinstead of mineral oil.

• Most of the HFCs are mixtures, which can behavedifferently than pure compounds under someconditions.

• Virtually all of the HFCs have higher vaporpressures than the refrigerants they are replacing,which can affect the settings of controls, valvesand safety devices. Certain hermetic compressorsare not approved for operation with some HFCs,due to high-pressure ratio stress on bearing surfaces.

14

15

applications, because the refrigerant delivershigher efficiency and better TEWI than otherchoices. The refrigerant also has many benefitsthat make it an excellent refrigerant for use incommercial applications. To date, optimizedsystem-testing has shown that R-410A delivershigher system efficiency than R-22. R-410Aevaporates with a 35 percent higher heat-transfercoefficient and 28 percent lower pressure drop,compared to R-22.

Additional system performance enhancementshave been gained by sizing for equal pressuredrop and reducing the number of coil circuitsneeded to increase the mass flux. The higherdensity and pressure also permit the use ofsmaller-diameter tubing, while maintainingreasonable pressure drops.

Because systems that use R-410A have beenspecially designed to use less tubing and less coil,R-410A has emerged as a very cost-effectiverefrigerant. Fewer materials, along with reducedrefrigerant charge and better cyclic performance,also contribute to the affordability of R-410A.

R-410A operates at 50 percent higher pressurethan R-22. Anyone handling these units shouldreceive training on the technical aspects of thenew R-410A systems, at which time they can learnproper joint-brazing and critical maintenance tipsfor this new refrigerant.

R-410A cannot be used as a retrofit refrigerantwith existing equipment; it should only be used in new equipment (including compressors)specifically designed for it. Existing R-22compressors cannot meet UL and industry design standards with these higher pressures.

Fractionation – Since the components of a zeotropicmixture possess different vapor pressures, undercertain conditions they may leak from a system atdifferent rates. As a result, the refrigerantcomposition may change over time, with acorresponding change in performance.

Zeotropic mixtures currently available in themarketplace with a glide of less than six degreesFahrenheit (3.3 degrees Kelvin) approximate anazeotrope so closely that fractionation should not bea serious problem. The only exceptions to this aresystems that use multiple evaporators or floodedevaporators.

To ensure that fractionation does not occur duringcharging, it is recommended that zeotropic mixturesbe liquid charged rather than vapor charged. Liquidmust be removed from the refrigeration cylinder. It then can be flashed through a metering device and charged into the system in its vapor state. Therefrigerant manufacturer’s recommendation shouldbe closely followed.

Refrigerants for new AC applications

R-410AR-410A is one of the most important HFCrefrigerants helping the industry meet the 2010deadline. R-410A is a near-azeotrope compositionof 50 percent R-32 and 50 percent R-125.

Ample research has shown that R-410A is the best replacement for R-22 refrigerants in new air conditioning systems – and manufacturersagree. Most major residential air conditioningmanufacturers already offer R-410A product lines.Since the 13 SEER residential energy-efficiencyregulations went into effect in 2006, most majorresidential air conditioning manufacturers haveimplemented the transition to more energy-efficient product lines using R-410A.

R-410A has quickly become the refrigerant ofchoice for use in residential air conditioning

and maintain an acceptable operating efficiency.This, combined with the greater compressordisplacements required, results in a system that willbe more costly than R-22 systems today. The heat-transfer coefficient of R-134a is also lower than thatof R-22, and tests show that system performancedegrades with its use. In summary, manufacturerswould need to invest significant time and capital toredesign refrigeration systems from R-22 to R-134aand ultimately would have a design with inherentlylower performance or higher cost; therefore, forresidential and smaller commercial systems in whichR-22 has traditionally been used, we feel that R-134ais the least likely HFC candidate.

For large commercial air conditioning systemsfeaturing screw technology, R-134a may offer thebest solution for a low-investment, simple redesign.For large commercial air conditioning systemsfeaturing scroll compressors, R-410A represents the best refrigerant choice.

With the exception of ozone-depletion potential,Emerson believes that R-134a possesses the samedeficiencies as R-12 and represents a step backwardfor most applications. These deficiencies includelarger-displacement compressors and larger-diametertubing, compared to that required for use with high-pressure refrigerants.

Retrofit HFC refrigerants

There are several HFC retrofit refrigerants that havebeen developed for servicing R-22 air conditioningequipment.

Oil return to the compressor is critical to compressorreliability and the overall long-term reliability of thesystem. HFC refrigerants such as R-410A and R-407Cthat are miscible with POE oil are acceptable becausethey meet oil return requirements. However, HFCrefrigerants that claim they can be used with mineral oilare not approved by Emerson for use with Copeland®compressors in air conditioning applications. This isbecause several published sources have demonstrated

R-407C R-407C is a blend of R-32, R-125 and R-134a. Of thehigher-temperature HFC options, R-407C was designedto have operating characteristics similar to R-22. Themajor concerns surrounding R-407C are in its relativelyhigh glide (approximately 10 degrees Fahrenheit) andthe efficiency degradation, when compared to R-22;however, the use of this refrigerant provides thesimplest conversion of the HFC alternatives. R-407Cwas the initial choice of some manufacturers whowanted to move quickly to an HFC alternative. In thelong run, however, the lower-efficiency performance of this refrigerant makes it a less attractive alternative,when compared to R-410A, for air conditioningapplications.

Care should be taken when applying R-407C in any applications in which glide can impact systemperformance by fractionation in flooded-evaporator or multi-evaporator designs. Also, R-407C should not be viewed as a drop-in for new R-22 systems orapplications. Like all HFCs, R-407C requires the use ofPOE lubricants, and other system design modificationsmay be required for R-407C to operate acceptably in R-22 systems.

R-134a R-134a was the first non-ozone-depleting fluorocarbonrefrigerant to be commercialized. It was developedmore than 20 years ago to have characteristicssimilar to R-12. R-134a has been generally acceptedby the automotive air conditioning industry, becauseof its low hose permeability and high critical temperature.Domestic refrigerator producers also find R-134a tobe a viable refrigerant for their products.

R-134a has the benefit of being a single-componentrefrigerant and, therefore, does not have any glide.The disadvantage of R-134a lies in its relatively lowcapacity, compared to R-22. To utilize this refrigerant,all of the tubing within the heat exchangers andbetween the components of a system would need to be significantly larger, to minimize pressure drops

16

17

continued concern with oil return for systems withoutoil separators, like air conditioning applications.

The HFC retrofit refrigerants that are not approvedinclude R-417A, R-422A/B/C/D, R-434A, and R-421A.Independent testing on these refrigerants has shownreductions in system capacity, efficiency losses andsignificant delays in return of oil. (Figure 8)

The HFC refrigerant R-410A has been fully tested byEmerson and is our recommended choice for a non-ozone depleting (HFC) refrigerant to replace R-22 innew equipment. However, if you must service an R-22system with an HFC retrofit refrigerant, R-407C withPOE oil is acceptable for compressor reliability andwarranty. For more information on R-407C, pleasereview our Refrigerant Changeover Guidelines: R-22 toR-407C (Form #95-14), which can be found in ourOnline Product Information at EmersonClimate.com.

For more information on refrigerants, go toEmersonClimate.com/refrigerant/ac.

Future low-GWP fluorocarbon refrigerants Several refrigerant manufacturers are developingrefrigerants for automotive air conditioningapplications that will meet 2011 European Unionenvironmental standards for reducing the use of GWP

substances. Sometimes these R-134a replacementsare referred to as Fluid H (Honeywell) or DP-1(DuPont) refrigerants. These future low-GWPfluorocarbon refrigerants are being developed as CO2 alternatives.

Possible fluorocarbon refrigerants underdevelopment are two-blend azeotropes that havematerial compatibility similar to R-134a. They willlikely obtain ASHRAE A1 nonflammable designationand have a GWP much lower than the Europeanmaximum of 150, with zero-ozone-depletionpotential. These refrigerants will likely be promotedas direct replacements for R-134a, with only minorchanges to systems required. Manufacturers positionthese refrigerants as more practical and cost-effectivethan CO2.

The potential downside of future fluorocarbonrefrigerants is that they are composed of some new molecules and contain fluorine, which is notconsidered a “natural refrigerant.” They will behigher-cost refrigerants than R-134a and also requireapproximately five percent more refrigerant charge. It may take some time to bring these new refrigerantsto market, due to the time required to completetoxicity-testing and build new production lines.

original refrigerants, used nearly 100 years ago.Although thermodynamic performance of a simpleCO2 cycle is very poor – 30 to 50 percent worse thanHFCs – “poor” refrigerants such as CO2 tend to havevery good heat-transfer characteristics, but requireadditional cost for cycle modifications.

Many CO2 systems are designed for transcriticaloperation. These systems tend to have lower energyefficiency, compared to conventional systems, andtheir system design is very different from conventionalsystems. Transcritical operation means that the CO2does not condense at temperatures above 31degrees Celsius (87.8 degrees Fahrenheit); andinstead of using a traditional condenser, a gas coolermust be used. The pressures created by CO2 presentsignificant challenges in its usage. High side pressuresare about 2,500 pounds per square inch (psi), andexcursions can go to 4,000 psi. This is a technical andcost challenge not only for the compressor, but also for the heat exchangers.

Typical cycle efficiency is 40 percent of the idealCarnot13 refrigeration cycle, where the Coefficient of Performance (COP) is 2.5, versus 68 percent (COP 4.2) for an R-134a system at high-temperatureconditions. Microchannel heat exchangers, gas/suction heat exchangers or CO2 expanders improvesystem performance, with some added cost andcomplexity.

The cost impact of CO2 in transcritical systems issubstantial. Due to the higher pressure, modificationsare required on the compressor shell, valves, rings,terminal and seals, as well as the pressure-relief valveand microchannel heat exchanger. Performanceimplications require a Cooler/Suction Heat Exchanger(CSHX), a discharge-pressure regulator valve and alow side accumulator to control excess charge. Anadditional oil separator is required, due to oilcirculation and return problems.

The comparably high pressure level andthermodynamic properties of CO2 as a refrigeranthave driven system designers to consider subcriticalCO2 systems. These systems operate much likeconventional cascade refrigeration systems. In asubcritical system, CO2 is used as a direct expandingmedium in the low-temperature stage, and different

Ammonia Ammonia (NH3) is widely used as a refrigerant in verylarge industrial refrigeration plants. As a halogen-freerefrigerant, ammonia has the benefit of zero-ozone-depletion potential and no direct GWP; however, itshigh toxicity generally limits its application toindustrial refrigeration applications. In very largeammonia systems, the efficiency is comparable tosimilar systems with R-22 refrigerant.

Although ammonia is widely available and is a low-cost substance, there are significant challenges toapplying ammonia as a refrigerant in commercialrefrigeration systems. Ammonia systems have higherdischarge pressures than R-22. Oil managementbecomes a major issue in ammonia systems, sincethe oils used are typically not soluble in ammonia.The very low-mass flow of ammonia compared to R-22 is an advantage for large ammonia plants, butbecomes a challenge in smaller commercial systems.Additionally, ammonia is highly corrosive on coppermaterials, so refrigerant lines must be steel, and thecopper in the compressor-motor windings must beinsulated from the gas.

The major drawback of using ammonia in commercialrefrigeration applications is its high toxicity andflammability level. This alone requires unique safetymeasures that are well beyond the scope of mostcommercial installations.

Due to its system chemistry challenges, ammoniawas not a serious R-22 alternative candidate in theAREP program.

Carbon dioxide Increasing environmental concerns about thepotential direct emissions from HFC-based systemshave led to legislation and taxation schemes in partsof Europe that favor the usage of carbon dioxide(CO2) as a refrigerant, especially in certainrefrigeration applications. CO2 is given thedesignation R-744. CO2 is environmentally benign,versus other refrigerants, is nonflammable, has lowtoxicity, is widely available and is a low-first-costsubstance. These are the reasons it was one of the

Halogen-free refrigerants

13Carnot is a theoretical measurement of the ideal refrigeration cycle.

18

19

refrigeration system with propane are similar to R-22.Propane has been applied in systems with low charge– less than 150 grams (approximately 5 ounces) –and often outside the U.S.

The disadvantage of propane and all hydrocarbons is that they are highly flammable. System costsincrease significantly, due to the required safetymeasures. Special considerations must be taken forexcess pressures associated with vapor compressionand electrical connections, as well as ventilation to prevent flammable gas mixtures. Commercialoperators typically do not want to risk the safety-code issues and litigation risks associated with usingpropane in an air conditioning or refrigeration system.

Propane has the benefits of zero direct GWP and highsystem performance; however, its flammability hasdisqualified it as an R-22 replacement. The safetyissues of a flammable refrigerant require significantsystem adders and redesign, which may includesecondary loop configurations that reduce efficiency.

A “safe” hydrocarbon system would have to be leakproof with special testing, would contain a secondaryloop system that would suffer from heat-transfer and pumping losses, and would have to be explosionproof, with special electrical hardware and techniciantraining.

options exist for the medium-temperature stage. This way compressors in the low-temperature stageare only exposed to pressure levels similar to high-pressure air conditioning applications, such as with R-410A. Subcritical operation might prove to be thebest application of CO2 as a refrigerant for somecommercial refrigeration applications.

In summary, CO2 has many technical and costchallenges. The low efficiency and cycle complexityare the fundamental limitations; however, CO2 mayprove to be commercially viable in transport and low-temperature cascade systems, as well as in someheat-pump applications. Whether transcritical orsubcritical CO2 systems are considered, CO2technology cannot be seen as a drop-in replacementfor any of the other refrigerants mentioned in thispaper. Any application of CO2 requires a thoroughassessment of system efficiency, TEWI, life-cycle cost,technical feasibility, reliability and safety.14

Hydrocarbons The push for halogen-free refrigerants has ledmanufacturers to investigate hydrocarbons as areplacement for R-22. Propane (R-290) is consideredas a replacement, because it is a halogen-freesubstance with no ozone-depletion potential and low direct GWP. Propane is widely available and is alow-cost substance. The operating pressures of a

1,774 1,4302,088

14asercom.org

perceived as “thickness,” or resistance to pouring.Viscosity describes a fluid’s internal resistance to flowand may be thought of as a measure of fluid friction.

Oil return and heat transfer – These challengingcharacteristics of conventional hydrocarbonlubricants (mineral oil/alkyl benzene) when used withHFC refrigerants continue to be investigated, due toease of handling and lower cost.

Stability and compatibility – Stability and compatibilitywith commonly used refrigeration components andthe refrigerant itself are important. Emerson hasperformed extensive sealed-tube materialcompatibility tests and has found that selected POEoils have acceptable compatibility with materialscommonly used in air conditioning systems.

Most manufacturers of hermetic and semi-hermeticcompressors have determined that POEs are the bestchoice of lubricants for use with the new generationof chlorine-free HFC refrigerants. In addition toproviding superior lubrication with the new refrigerants,POE oil has other advantages that increase itsattractiveness for use in air conditioning systems.

What is polyol ester? Polyol ester (POE) oils are a family of syntheticlubricants used primarily for jet engine lubrication.There are many types and grades of POE oils, and it isimportant to understand that all POE oils are not thesame. Areas of difference include lubricity, miscibilitywith refrigerant, viscosity, additive packages, pourpoint and moisture content. Unlike natural mineraloils, POE oil is completely wax free. In addition, POEoil has better thermal stability than mineral oils.

POE oil is made from more expensive base stockmaterials than traditional refrigeration mineral oilsand therefore costs more; however, some of thecharacteristics of POE oil help offset the higher cost. For instance, POE oil is backwards compatible with mineral oil, which means that a compressorcontaining POE oil can be installed in an airconditioning system that contains mineral oil.Furthermore, the POE oils we recommend arecompatible with all refrigerants, so that a properlyspecified compressor containing POE oil can be

Emerson’s policy continues to be one of notdeveloping or selling products for use withflammable or toxic refrigerants, for the followingreasons:

• We believe there are alternative refrigerants thatare not flammable or toxic and provide equal orbetter environmental characteristics (based onTEWI) at equal or lower cost.

• Adequate safety standards do not exist forsystems containing over 50 grams of ahydrocarbon refrigerant, which covers almost all Emerson® compressor applications.

Key characteristics of these refrigerants aresummarized in Figure 9.

When a lubricant is evaluated for use in a compressor,the following characteristics must be considered, inaddition to basic considerations, such as productsafety and environmental impacts:

Lubricity – The ability of the lubricant to minimizefriction and wear between the rotating or slidingsurfaces under all operating conditions, includingadverse conditions, such as high load, flooded startand floodback. With regard to lubricity, the chlorinein CFCs and HCFCs significantly enhances boundary-layer lubrication in bearings used with mineral oil.Since HFCs do not contain chlorine, POE oil must beformulated to provide the necessary antiwearcapabilities without the presence of chlorine inrefrigerants.

Miscibility – The ability of oil to mix with therefrigerant in all areas of the system, so that it canreturn to the compressor without stagnating in theconnecting lines, heat exchangers or receiver. Mineraloils are not miscible with pure HFCs; thus, anymineral oil that leaves the compressor in a pure HFCsystem may get trapped in the connecting lines orevaporator. Since oil acts as an insulator in heatexchangers, oil trapped in the evaporator cansignificantly reduce system capacity and efficiency, as well as jeopardize compressor reliability.

Viscosity – A measure of the resistance of a fluid todeformation under shear stress. It is commonly

Lubricants

20

21

It is imperative that any system that contains POE oil beclearly marked to identify the composition of the oil and refrigerant contained in the system, to avoid cross-charging with the wrong lubricant or refrigerant.

Handling POE lubricants POE is substantially more hygroscopic than mineraloil. Consequently, exposing POE to air will result inthe oil’s absorbing moisture more quickly than wouldmineral oil. The hygroscopic nature of POE oils meansthat moisture in the system can rise to levels that areunacceptable in air conditioning systems.

POE also holds moisture more tightly than mineraloil, so removing it with an evacuation process is moredifficult. The Emerson specification for maximummoisture content of POE oil to be added to airconditioning systems is 50 ppm. If the moisturecontent of the oil in a system rises above 100 ppm,corrosion of various metallic materials and copperplating may occur. In addition, acids and alcohols canbe formed through a process called hydrolysis, whichwill have a negative impact on long-term compressorand system durability and performance.

The moisture level of POE oils can increase whenexposed to air. Obviously, it is imperative thatcontainers of POE be kept sealed, except when the oilis actually being dispensed. POE oil must be storedproperly in its original container, because manyplastics used to package oils are permeable tomoisture. One of the requirements for Emerson toqualify a POE lubricant is proper packaging, toprevent moisture contamination during normal shelfstorage. For this reason, Emerson approves only POEoils that are presently packaged in metal cans.

It is also important that compressors and systemsbe kept closed, except when work is actually beingperformed on the equipment. Leaving equipmentopen during work breaks, overnight or whenperforming other work will quickly result inunacceptable levels of moisture in POE lubricants.

It is equally important that undesirable contaminantspicked up as a result of POE oil’s increased solvencybe filtered out. Both can be achieved by proper

installed in a system that contains CFCs, HCFCs or the new HFCs; thus, for the higher initial cost of POEoil, we obtain significant flexibility in the face of thechanges brought on by the CFC issue.

A second positive aspect of POE oil is that it can bedesigned to meet lubricity requirements equivalentto those of mineral oils used with CFCs and HCFCs.Standard laboratory lubricant bench tests (Falex, pinon v-block and four-ball wear tests) and acceleratedcompressor-life tests are used to verify these results.Contributing to the superiority of POE oil is the factthat the viscosity of POE oil has less variation withtemperature than mineral oil.

A third positive aspect of POE oil is that its miscibilitywith refrigerant can be matched so easily to that ofmineral oil in R-12, R-502 or R-22; thus, POE oilshould have oil-return characteristics similar tomineral oil with conventional chlorine-containingrefrigerants.

Finally, from an environmental perspective, POE oil is highly biodegradable and should provide lowecotoxicity.

POE oil can be used with all refrigerants.Because POE oil can be used with all refrigerants and isbackwards compatible with mineral oils commonly usedwith CFCs and HCFCs, it offers the greatest level offlexibility in dealing with the uncertainties imposed bythe CFC issue. For example:

• Initially using POE oil in a new HCFC system will allowthe easy transition to HFCs, without the expensive,repetitive flushing procedure needed to remove themineral oil from the system.

• During system service, if POE oil is used to replaceany mineral oil removed from a system, it begins theprocess to flush the system of mineral oil, so thatconversion to an HFC can be performed with fewersteps later.

• POE oil can also be used with the intermediate HCFCmixtures if they are used to replace CFCs. A mixtureof at least 50 percent POE oil in mineral oil providesexcellent lubrication and will begin the flushingprocedure if a switch to HFCs occurs in the future.

measure of flexibility in dealing with the manyrefrigerant options being introduced into the market.This flexibility should help reduce confusion overexactly which lubricants and refrigerants are compatible.

Emerson has qualified the following POE oils (whichare compatible with each other): Copeland® brandUltra 22CC™ oil, Mobil EAL™ Arctic 22CC oil and ICIEMKARATE™ RL32CF oil. Specifications for POE oilsapproved by Emerson are available atEmersonClimate.com.

Emerson actively promotes the idea that responsibleuse is the key to safety and environmental stewardship.As already discussed, HFC refrigerants are the key to energy-efficient air conditioning equipment. But other factors also figure into optimized energyefficiency (see Figure 10). Prompt maintenance isimportant to keeping systems running not onlylonger, but also more efficiently. Preventivemaintenance routines can help extend the life ofequipment, increase energy efficiency and reduce the potential for refrigerant leakage.

installation and service techniques, as well as use of the correct filters and driers. Emerson applicationguidelines recommend the use of a liquid-line filterdrier with HFC refrigerants.

The impending phaseout of chlorine-based refrigerantsmandates that the air conditioning industry move tolubricants that will work satisfactorily with the newHFC refrigerants. These lubricants must have levels of reliability and performance as good as – or betterthan – those previously experienced with traditionalmineral oils used with chlorine-containing refrigerants.It appears that selected POE lubricants meet thisrequirement. Because of its compatibility with allcommonly used refrigerants, POE offers a large

15arap.org/responsible.html

Responsible-use principles

22

23

Future direction

It is important to recognize that this is anevolutionary process. Today’s HFCs are the nextsteps, but they may not be the last steps in theprocess. As technologies develop and newapplications and system designs continue to emerge,other refrigerants may be developed and applied inthe future.

No HFC refrigerant can cause direct global warming if it is properly contained. Within the HVACR industryand in others, we expect to see increased emphasison refrigerant recovery and leak prevention in thecoming years. TEWI also points to the critical role of system operating efficiency as a major driver forsubstantial GWP reduction related to powergeneration. As the concern over potential climatechange grows, Emerson Climate Technologies will continue to work closely with refrigerant and system manufacturers, industry organizations andgovernment agencies to improve compressorperformance, efficiency and reliability, while reducingenvironmental impact.

Containment is one way to promote the responsibleuse of refrigerant. Equipment manufacturers areworking to design systems that require less chargeand have fewer leaks. There can be no direct impacton the environment from any refrigerant that iscontained in a well-designed system. Early leakdetection and repair will reduce refrigerantconsumption. And finally, all refrigerants should berecovered, reclaimed and recycled at the end of thesystem life.

Responsible use of refrigerants:15

• Contain refrigerants in tight or closed systems andcontainers, minimizing atmospheric releases.

• Encourage monitoring after installations tominimize direct refrigerant emissions and tomaintain energy efficiency.

• Train all personnel in proper refrigerant handling.

• Comply with standards on refrigerant safety,proper installation and maintenance (e.g.,ASHRAE-15, ISO-5149 and European StandardEN378).

• Design, select, install and operate to optimizeenergy efficiency.

• Recover, recycle and reclaim refrigerants.

• Continue to improve equipment energy efficiencywhen cost-effective.

The next generation of refrigerants has beenestablished. As reviewed here, HFCs have zero-ozone-depletion advantages over R-22; however, they stillhave moderate direct GWP.

HFC refrigerant: A hydrofluorocarbon, containinghydrogen, fluorine and carbon molecules (e.g., HFC R-134a).

HGWP: Halocarbon Global Warming Potential. This issimilar to GWP, but uses CFC-11 as the reference gas,where CFC-11 is equal to one (reference GWP for R-11= 4,000).

Near-azeotrope: A zeotropic blend with a smalltemperature and composition glide over theapplication range and no significant effect on system performance, operation and safety.

Pure compound: A single compound, which does not change composition when changing phase.

TEWI: Total Equivalent Warming Impact. TEWIintegrates the global warming impacts ofequipment’s energy consumption and refrigerantemissions into a single number, usually expressed interms of CO2 mass equivalents. The calculated TEWIis based on estimates for: (1) the quantity of energyconsumed by the equipment over its lifetime; (2) themass of CO2 produced per unit of energy consumed;(3) the quantity of refrigerant released from theequipment over its lifetime; and (4) the GWP of thatrefrigerant, expressed in terms of CO2 massequivalent per unit mass of refrigerant.

Zeotrope: A blend, when used in refrigeration cycles,that changes volumetric composition and saturationtemperatures to varying extents as it evaporates(boils) or condenses at constant pressure.

Azeotrope: A blend, when used in refrigeration cycles,that does not change volumetric composition orsaturation temperature appreciably as it evaporates(boils) or condenses at constant pressure.

Blend: A refrigerant consisting of a mixture of two or more different chemical compounds, often usedindividually as refrigerants for other applications.

CFC refrigerant: A chlorofluorocarbon, containingchlorine, fluorine and carbon molecules (e.g., CFC R-12).

Fractionation: A change in composition of a blend by preferential evaporation of the more volatilecomponent(s) or condensation of the less volatilecomponent(s).

Glide: The difference between the starting and endingtemperatures of a phase-change process by a refrigerant(at constant pressure) within a component of arefrigerating system, exclusive of any subcooling orsuperheating. This term is usually used in describingthe condensation or evaporation process.

GWP: Global Warming Potential. This is a measure of how much a given mass of greenhouse gas isestimated to contribute to global warming. It is arelative scale that compares the gas in question tothat of the same mass of carbon dioxide, whose GWP is 1.0.

Halogen-free refrigerant: A refrigerant that does notcontain halogen compounds, such as chlorine andfluorine (e.g., hydrocarbons, ammonia, etc.). This isalso commonly referred to as a “natural refrigerant,”since it is found in nature.

HCFC refrigerant: A hydrochlorofluorocarbon,containing hydrogen, chlorine, fluorine and carbonmolecules (e.g., HCFC R-22).

Glossary of terms

24

25

Appendix

For more information the following suggestedreading materials are available from Emerson, via our online product information (OPI) website,EmersonClimate.com:

• Emerson Climate Technologies, Inc. AcceptedRefrigerants/Lubricants, form number 93-11

• Refrigeration Oils, Application EngineeringBulletin AE-1248

• Copeland Scroll® Compressors, ApplicationEngineering Bulletin AE 4-1308

• Application Guidelines for R-410A Compressors,Application Engineering Bulletin AE-1331

• R-134a, Application Engineering Bulletin AE-1295

• Refrigerant Changeover Guidelines:

(CFC) R-12 to (HCFC) R-401A 93-02

(CFC) R-12 to (HCFC) R-401B 93-03

(CFC) R-12 to (HFC) R-134a 93-04

(HCFC) R-22 to (HFC) R-407C 95-14

Access the EK Filter Drier and HMI white papers atEmersonflowcontrols.com/web/SystemProtectors.asp.

Authors

Ken MonnierKen Monnier, vice president of Emerson Climate Technologies, Inc. - Air Conditioning division’s engineering department, responsible for Copeland brand products, has more than 20 years of experience in the HVACR industry, as well as extensive experience incompressor engineering and technology.

Monnier graduated from the University of Dayton, where he studied mechanical engineering and earned a bachelor oftechnology degree. He is an active member of the American Society of Mechanical Engineers (ASME), a committee member ofEngineering Technology Industrial Advisory Committee at the University of Dayton and a steering member of the Upper MiamiValley Tech Prep Consortium. He has also been president of the Copeland Management Association (now known as EmersonEmployees Coming Together); was a featured speaker in the 2000 and 2002 ASHRAE technical seminars; is the holder of sixcompressor-related patents; and co-authored a paper on scroll technology published for the Institute of Refrigeration in 1990.

Warren BeetonWarren Beeton is a 1966 graduate of Cornell University, with a master’ s degree in mechanical engineering. He has 35 years ofexperience in the air conditioning and refrigeration industry, including positions in marketing product management andengineering product development. He has worked on the development of a wide range of products, including centrifugal chillersand compressors, unitary air conditioners and heat pumps, residential gas furnaces, and reciprocating and scroll compressors.

Warren joined Emerson Climate Technologies, Inc. in 1995, as vice president of engineering for Emerson Climate Technologies,Inc. – Air Conditioning division. In 1999 he was appointed vice president of engineering for Emerson Climate Technologies, Inc. –Refrigeration division.

Warren is active on several ASHRAE and ARI committees. He is also a member of the Board of the Alliance for A ResponsibleAtmospheric Policy.

Brian BuynacekBrian Buynacek is a graduate of Cornell University and the University of Dayton, with an MBA. and degrees in mechanicalengineering. He has 15 years of industrial marketing experience, including positions in marketing product management, keyaccount management, and application and manufacturing engineering. Brian is a registered professional engineer in the state of Ohio.

As a senior consultant with Emerson’ s Design Services Network, Brian has driven more than 50 key marketing and engineeringprojects in the past five years.

Contributors Tim FletcherTim Fletcher is currently the manager of air conditioning aftermarket programsfor Emerson Climate Technologies. He is responsible for the rollout of EmersonClimate Technologies products, such as the UltraTech™ communicating system,Comfort Alert® diagnostics and Copeland Scroll Digital™ compressors, to airconditioning contractors, business owners and homeowners. Additionalresponsibilities include support of these products and technologies at EmersonClimate Technologies Authorized Full-Line WholesalerSM, Authorized CopelandBrand Wholesaler and independent HVAC distribution locations. The productfeedback, field-trial results and end-user information gathered by Tom is usedto provide input on new product development and direction.

His background includes 15 years at Copeland Corporation (now known asEmerson Climate Technologies, Inc. - Air Conditioning division). Tim began hiscareer in the Copeland Scroll compressor engineering department followed byassignments as an International project engineer, sr. Application engineer,manager - refrigeration end-user team, manager of air conditioning service and most recently, brand manager of air conditioning contractors. Tim holds a bachelor of science degree in mechanical engineering from the University ofCincinnati and an MBA in marketing from the University of Dayton.

26

27

Peter MatzigPeter Matzig, a graduate of SouthernColorado State, has over 33 years ofexperience in the HVACR industry. Hejoined Emerson Climate Technologies,Inc. in 1984, and has worked throughoutthe United States and Europe as anapplication engineer for the company.Prior to his time at Emerson, Peterserved in the United States Air Forceand also worked as a field servicetechnician.

He has written and published numerous engineering bulletins on key Emerson compressor technologies, including bothreciprocating and Copeland Scroll compressors. Recently Peter was integral to the engineering and testing of the latest generation of Copeland Scroll compressors.

Peter’s expertise has also been called upon by the North AmericanTechnician Excellence (NATE) certification organization. He has collaborated with the group to craft its certificationtests, aiding in the training of the most trusted technicians in the HVAC industry.

Tony YoungTony Young graduated from The OhioState University with a bachelor ofscience degree in mechanicalengineering and the University of Daytonwith an MBA. He has nine years ofexperience in the HVACR industry andhas held positions including productmanagement, strategic planning andbusiness development and marketingmanager for refrigeration and airconditioning products.

During his time at Emerson Climate Technologies, Tony hashelped launch products for multiple global markets, in additionto supporting air conditioning OEMs during the 2006 13 SEERtransition planning and execution. Tony has presented onvarious industry topics and trends at Refrigeration ServiceEngineers Society (RSES), Air Conditioning Contractors ofAmerica Association, Inc. (ACCA) and Plumbing-Heating-Cooling Contractors Association (PHCC) conferences, to raiseawareness with HVACR educators and contractors on industrychanges that will impact them over the coming years.

Bart PowelsonBart Powelson holds a bachelor of science degree and an MBA inmarketing from Purdue University. He has 13 years of experience in theair conditioning and refrigerationindustry. Bart has held several key air conditioning and refrigerationmarketing roles at Emerson ClimateTechnologies, Inc. He has also servedas manager of business developmentand strategic planning. Currently, Bart is director of commercialair conditioning marketing for Emerson Climate Technologies,Inc. – Air Conditioning division.

Bart is responsible for launching new compressor products andtechnologies, monitoring key air conditioning market trendsand providing commercial marketing support to manufacturersand contractors. He has led numerous launches of commercialcompressor and electronic products, including new refrigerants,capacity modulation, expanded displacement offerings andcompressor diagnostics. Bart is an active participant in the U.S. Green Building Council.

Karl ZellmerKarl Zellmer, vice president of sales for Emerson Climate Technologies, Inc.Air Conditioning division, has morethan 26 years of experience in theHVACR industry. Karl graduated fromIndiana University, where he earned abachelor of science degree in finance.He subsequently earned his MBA inmanagement from Xavier University.Karl is an active participant in industryevents, including trade shows, advisory councils and discussion panels.

In his current position, Karl is responsible for sales andtechnical support of air conditioning products. He is also one of Emerson Climate Technologies’ experts on the transitionfrom ozone-depleting HCFC refrigerants, like R-22, to HFCrefrigerants, like R-410A, for air conditioning and the impactthat new regulations have on the HVAC industry.

About Emerson

Emerson (NYSE: EMR), based in St. Louis, is a global leader in bringing technology and engineering together to provide innovativesolutions to customers through its network power, process management, industrial automation, climate technologies, andappliance and tools businesses. For more information, visit GoToEmerson.com.

About Emerson Climate Technologies

Emerson Climate Technologies, a business of Emerson, is the world’s leading provider of heating, ventilation, air conditioningand refrigeration solutions for residential, industrial and commercial applications. The group combines best-in-class technologywith proven engineering, design, distribution, educational and monitoring services to provide customized, integrated climate-control solutions for customers worldwide. The innovative solutions of Emerson Climate Technologies, which include industry-leading brands such as Copeland Scroll and White-Rodgers, improve human comfort, safeguard food and protect the environment.

Emerson Climate Technologies, Inc., is the world’s leading compressor manufacturer, offering more than 10,000 compressormodels. A pioneer in the HVACR industry, the company led the introduction of scroll technology to the marketplace. Todaymore than 50 million Copeland Scroll compressors are installed in residential and commercial air conditioning and commercialrefrigeration systems around the world. Emerson Climate Technologies, Inc. is headquartered in Sidney, Ohio. For moreinformation, visit EmersonClimate.com.

Form No. 2007ECT-136R3 (10/08)Emerson Comfort Alert, Copeland, Copeland Scroll, Copeland Scroll Digital, Emerson Climate Technologies, Emerson Climate Technologies Authorized Full-Line Wholesaler, Ultra 22CC,UltraTech and White-Rodgers are trademarks of Emerson Electric Co. or one of its affiliated companies. ©2007 Emerson Electric Co. All rights reserved. Printed in USA.