RefRigeRation &aiR conditioning division technical paper

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Worldwide R22 countdown

Technical paper Worldwide R22 countdown Technical paper Worldwide R22 countdown

Retrofitting

it is unfortunately not feasible for danfoss to test all possible R22 substitutes upon its entire extensive product range. therefore no war-ranty is available for compressors and controls in the event of substitution of R22 by drop-in of substitute refrigerants.

on the other hand, danfoss offers a complete range of hermetic compressors designed to

if the establishment of a complete new plant is not feasible, a option may be retrofitting with compressors suitable for use with the substitute refrigerants.

When retrofitting there are several potential pitfalls to be aware of:

Missing pressure manometersno pressure manometers showing saturated vapour and liquid are available for any of the substitute refrigerants. Most tables show absolute pressure, whereas most pressure manometers indicate over pressure. ensure that the real-time superheat and sub-cooling are monitored correctly. there is a real risk of confusion, which may lead to poor system per-formance or even compressor failure. the sys-tem reliability could be affected seriously.

Oil changesome refrigerants are promoted as drop-in, meaning that they can be used in combination with the same type of mineral oil which was

run on the substitute refrigerants R404a and R507. these compressors are available in ver-sions compatible with a wide range of volt-ages, controls and other components. for ac applications, danfoss also provides compressors and controllers designed for use with the refrigerants R407c and R410a.

used with R22. the level of oil return should be acceptable, such that only a slight oil film builds up in the heat exchanger, often enhanc-ing heat transfer. if oil return is not adequate however, this oil film can become thick enough to actually create a thermal barrier in the heat exchanger. if this occurs, danfoss recommends applying a minor correction factor on the coil efficiency.

it is worth noting that reduction in heat exchanger efficiency can be avoided by using a polioester (Poe) based lubricant instead of mineral oil.

Capacity drop and COPsome of the refrigerants promoted as drop-in can affect the system performance adversely, resulting in a capacity drop. for example, shell and tube type heat exchangers are incompat-ible with refrigerants exhibiting a temperature glide.

Trade name Composition ODP GWPSafety group

Practical limit

kg/m3

Boilling temp.

(°C)

Temp. glide

(K)

Critical temp.

(°C)

Critical pressure

(bar)

Cond. temp. (°C)@ 26bars

R134a 100% R134a 0 1300 a1 0,25 -26,1 0 101 40,59 80

R22 100% R22 0,06 1700 a1 -40,8 96 49,9 63,2

R404a suva HP62 dupont 52% R143a - 44% R125 - 4% R134a 0 3750 a1 0,48 -47 0,8 71,6 37,3 55

R507a fX70-aZ50 atofina-allied

50% R143a - 50% R125 0 3800 a1 0,48 -46,7 0 71 37,15 54

R407c ac9000 & Klea66

52% R134a - 25% R125 - 23% R32 0 1600 a1 0,31 -44 7,4 87 48,2 58

R410a 50% R32 - 50% R125 0 1900 a1 0,44 -51 < 0,2 72 49,1 43

R417a isceon Mo59 dupont 46,6% R125 - 50% R134a - 3,4% R600 0 1950 a1 0,15 -38,01 5,14 90 40,35 68

R422a isceon Mo79 dupont/Rhodia

85,1% R125 - 11,5% R134a - 3,4% R600a 0 2530 a1 n/a -49 2,5 72 37,48 56

R422d isceon Mo29 dupont 65,1% R125 - 31,5% R134a - 3,4% R600a 0 2230 a1 - -45 4,5 81 39,04 62

R427a fX100 atofina 50% R134a - 25% R125 - 15% R32 - 10% R143a 0 1830 a1 - -42,7 7,1 86,8 44 64

R290 0 3 a3 0,008 -42,4 0 96,7 42,47 70

Refrigerant composition and propertiesIntroduction in the early 1980’s the international commu-nity began debating the drawbacks of Hcfc and cfc refrigerants, also known as R22, and looked for alternatives. the conclusion was that these refrigerants would be phased out by a series of deadlines, with final phase-out by 2040.

R22 was specially included as part of the solu-tion. in the Us, the use of R22 actually increased as a result, the general attitude being that the goals were unrealistic, and that developing countries would in fact need a longer phase-out period than agreed.

in the meantime, it seems there has been a global change of heart, and the 19th Meeting of the Un Parties to the Montreal Protocol in september 2007 agreed on the following more stringent commitments:

developed (non-article 5) countries commit-ted to reducing production and consumption of Hcfcs (R22) by 75% by 2010, by 90% before 2015, with final phase-out in 2020.

developing (article 5) countries committed to reducing production and consumption of Hcfcs (R22) by 1% by 2010, by 35% before 2020, by 67,5% by 2025, with final phase-out in 2030. in addition, a small percentage (2.5%) of the original baseline amount will be permit-ted in the developing countries until 2040.

the acceleration in phase-out of Hcfcs in the course of the next ten years implies that no new HCFC-based plant may be operated in either developed or developing countries thereafter.

in the Us, the environmental Protection agency (ePa) has established specific regula-tions for the implementation of the Montreal Protocol, focusing on phase-out of R22 by 2010. However for equipment manufactured prior to 2010 the phase-out deadline is 2020.

in order to meet this schedule, a series of ini-tiatives are being launched, including ePa´s greenchill advanced Refrigeration Partner-ship, involving several companies including grocery store chains, manufacturers of refrig-erating equipment, and also refrigerant man-ufacturers. the Partnership is aimed at helping supermarkets to phase out R22, which at this point is used in more than 70% of the 34,000 supermarkets located throughout the Us. Hfcs are clearly the main alternative refriger-ants currently under consideration in the Us, as witnessed by arkema’s opening the world’s largest R32 production plant in september 2007. the plant, located in colvert city, Ken-tucky, produces 25,000 tons per annum of R32, which is an essential component of Hfc blends such as R410a.

The recent agreements have no effect upon European legislation. the final european phase-out date for use of R22 in existing plants is 31.12.2014. its use in new cooling, air-conditioning and heat pump systems has been prohibited since January 2001 and further at January 2004 in combined ac and heat pump systems.

Substitutes for R22 Last year’s Montreal agreement has triggered new discussion of R22 substitutes.the following table lists the composition and properties of the existing refrigerants, includ-ing R22 substitutes.

2 dKRa.Pe.100.a2.02 / 520B3364 3dKRa.Pe.100.a2.02 / 520B3364

Technical paper Worldwide R22 countdown

© copyright danfoss a/s (Ra Marketing/MWa) June 2009

Conclusion

a capacity drop can affect applications in var-ious ways:

1. for applications which run continuously for long periods, such as cold rooms, compensa-tion for lower capacity can be made by increas-ing the running time.

2. conversely in other applications such as beer coolers or ice machines, the application demands instantaneous full capacity for a short cycle time. in these applications it is important to minimise capacity drop to main-tain the required performance level.

3. some applications, such as bottle coolers and milk tanks, are designed to comply with particular performance specifications. in these cases retrofit can extend lifetime, but the ret-rofitted plant will no longer be capable of meeting the original specifications.

Controller and valve sizea compulsory aspect of any retrofit is to check that the dimensions of all controllers and valves, such as solenoid valves and check valves, are correct. if not, then replace them as required.

When retrofitting, it is always advisable to change the expansion valve, or as a minimum, the expansion valve orifice.

in general, danfoss offers hermetic compres-sors and controllers for tested and approved refrigerants only. danfoss will not provide war-ranty for old and new compressors which are used with non-approved refrigerants or sub-stitutes. Based on the complex problems described above, danfoss recommends per-forming the following investigations before retrofitting a system or plant with hermetic compressors.

• Whichmodificationsareneeded?

• Aretheheatexchangerscompatible withthedrop-inrefrigerant? Please note that significant temperature glide may occur.

• Howdotheretrofitsaffectsystem performance?

• Isthemaximumoperatingpressureof the new refrigerant higher than the permissible limit for the existing pressure vesselsandcomponents?

When working towards achieving compliance with Regulation ec 842/2006, it is also worth considering investment in a new plant, which may well be the most environmentally respon-sible and economically viable option.

danfoss offers a wide range of components approved for use with R404a / R507, R 407c and R410a. Please contact your local danfoss sales office for further information according this subject.

Maximum operating pressurethe maximum operating pressure of certain drop-in refrigerants is higher than the permis-sible pressure limits of the existing pressure vessels and other components. therefore it is advisable to check the maxi-mum permissible operating pressure for all the system components, and replace them with correctly dimensioned components where necessary.

System reliabilityin order to optimise system reliability, danfoss recommends performing the following replacements and adjustments during the process of a retrofit.

• ReplaceallO-ringsandgaskets• Replacetheexpansionvalveorthe expansion valve orifice • Replacethefilterdrierwithadrierone size larger• Replacethesightglass• Adjusttheexpansionvalve• Adjustallcontrollers• Adjustthepressurecontrols

www.danfoss.com/R22

4 dKRa.Pe.100.a2.02 / 520B3364