REFRIGERANT REPO RT 21

A-501-21 EN

BITZER Kühlmaschinenbau GmbH Peter-Schaufler-Platz 1 // 71065 Sindelfingen // Germany Tel +49 7031 932-0 // Fax +49 7031 932-147 [email protected] // www.bitzer.de

Subject to change // 80050206 // 09.2020

A-501-21_EN_Cover.indd Alle Seiten 15.09.20 09:05 Refrigerant Report

Contents Page Essential revisions/supplements vs. 20th edition Refrigerant development and legal situation 3

Alternative refrigerants – overview 4

Environmental aspects 6 Global Warming and TEWI Factor 6 Eco-Efficiency 7

HCFC refrigerants 8 R22 as transitional refrigerant 8

HFC refrigerants 9 R134a as a substitute for R12 and R22 9 Alternatives to R134a 11

Refrigerant blends 13

Substitutes for R22 in refrigeration systems 17 R404A and R507A as substitutes for R22 and R502 17 R407A, R407B, R407F, R407H and R422A as substitutes for R22 and R502 18

Substitutes for R22 in air conditioning systems and heat pumps 20 R407C as substitute for R22 // R410A as substitute for R22 20 R417A, R417B, R422D, R438A and R427A as substitutes for R22 22 R32 as substitute for R22 23

"Low GWP" HFOs and HFO/HFC blends as alternatives to HFCs 24 Aspects on the development 24 R134a alternatives 24 Substitutes for R404A/R507A and R410A 25 Further development projects 26

Halogen free (natural) refrigerants 28

NH 3 (Ammonia) as alternative refrigerant 28 R723 (NH 3/DME) as an alternative to NH 3 29 R290 (Propane) as alternative refrigerant // Propylene (R1270) as an alternative to Propane 30

Carbon dioxide R744 (CO 2) as an alternative refrigerant and secondary fluid 33 Refrigerants for special applications 37

Lubricants for compressors 41

Refrigerant properties 42

Application ranges 44

Overview lubricants 45

to the BITZER to the digital Refrigerant Ruler App Android iOS Refrigerant Report

This edition supersedes all previous issues. Refrigerant development and legal situation

Stratospheric ozone depletion as well as at- than direct (CO 2-equivalent) emissions The so-called "TEWI" factor ( Total Equiva - mospheric greenhouse effect due to refriger - caused by HFC refrigerants, refrigerants lent Warming Impact) has been introduced. ant emissions have led to drastic changes in with high global warming potential (GWP) Meanwhile, another, more extensive the refrigeration and air conditioning tech- will in the future be subject to use restrictions assessment method has been developed nology since the beginning of the 1990s. or bans. This will affect primarily R404A and considering "Eco-Efficiency". Hereby, both R507A, for which alternatives with lower ecological (such as TEWI) and economical This is especially true for the area of com - GWP are already being offered. However, in criteria are taken into account (further mercial refrigeration and air conditioning order to achieve the legal objectives, substi - explanations see page 7). systems with their wide range of applica - tutes for further refrigerants and increased Therefore it is possible that the assessment tions. In former years the main refrigerants use of naturally occurring substances (N H , 3 of refrigerants with regard to the environment used for these systems were ozone deplet - CO , hydrocarbons) will become necessary. ing types, namely R12, R22 and R502; for 2 can differ according to the place of installa - special applications R114, R12B1, R13B1, This requires comprehensive testing of tion and drive method. these refrigerants, suitable oils and adjusted R13 and R503 were used. Upon closer evaluation of substitutes for the systems. Therefore a close co-operation originally used CFC and HCFC as well as The use of these substances is no longer exists with scientific institutions, the refriger - for HFCs with higher GWP, the options with allowed in industrialised countries, but the ation and oil industries, component manu - single-substance refrigerants are very limit - use of R22 has been extended through tran - facturers as well as a number of innovative ed. This includes e.g. R134a, which will be sitional periods. However, the European refrigeration and air conditioning companies. Union also commited to an early phase-out usable for quite some time based on its for R22, which was enforced in several A large number of development tasks have comparatively low GWP. Similarly, the stages (see page 8). The main reason for been completed. Suitable compressors for hydro-fluoro-olefins (HFO) R1234yf and this early ban of R22 contrary to the inter- alternative refrigerants are available. R1234ze(E) with a GWP < 10, which are also exempted from the F-Gas regulation. national agreement is the ozone depletion Besides the development projects, BITZER potential although it is only small. actively supports legal regulations and self Direct alternatives (based on fluorinated Since 2010, phase-out regulations became commitments concerning the responsible hydrocarbons) for almost all refrigerants of effective in other countries as well, for use of refrigerants as well as measures to higher volumetric refrigerating capacity and instance in the USA. increase system and components’ efficiency. pressure level than R134a can (mainly) only be "formulated" as blends. However, taking This implies enormous consequences for The following report deals with potential into account thermodynamic properties, the whole refrigeration and air conditioning measures of a short to medium-term change flammability, toxicity and global warming sector. BITZER therefore committed itself to towards technologies with reduced environ - potential, the list of potential candidates is taking a leading role in the research and mental impact in medium and large size very limited. Blends of reduced GWP in- development of environmentally friendly sys - commercial and industrial refrigeration, air clude in addition to R134a, R1234yf and tem designs. conditioning and heat pump systems. R1234ze(E) primarily the refrigerants R32, Furthermore, the experiences so far and the After the chlorine-free (ODP = 0) HFC refriger - R125 and R152a. ants R134a, R404A, R407C, R507A and resulting consequences for plant technology R410A have become widely established for are discussed. Besides halogenated refrigerants, Ammonia many years in commercial refrigeration, air (NH 3) and hydrocarbons are considered as substitutes as well. The use for commercial conditioning and heat pump systems, new ? ? ? challenges have come up. They concern pri - applications, however, is limited by strict marily the greenhouse effect: The aim is a safety requirements. Several studies confirm that vapour com - clear reduction of direct emissions caused Carbon dioxide (CO ) becomes more impor - pression refrigeration systems normally 2 by refrigerant losses and indirect emissions tant as an alternative refrigerant and sec - used commercially are far superior in effi - by particularly efficient system technology. ondary fluid, too. Due to its specific charac - ciency to all other processes down to a cold teristics, however, there are restrictions to a In this area, applicable legal regulations are space temperature of around -40°C. already in force, such as the EU F-Gas general application. The selection of an alternative refrigerant Regulation No. 517/2014 (BITZER brochure The following illustrations show a structural and the system design receives special sig - A-510) and a series of regulations already survey of the alternative refrigerants and a nificance, however. Besides the request for ratified or in preparation as part of the EU summary of the single or blended substance s substances without ozone depletion poten - Ecodesign Directive (BITZER brochure which are now available. After that the indi - tial (ODP = 0) especially the energy de- A-530). Similar regulations are also in vidual subjects are discussed. preparation or already implemented in Aus - mand of a system is seen as an essential tralia, Canada and the USA. On an inter- criterion due to its indirect contribution to For refrigerant properties, application national level, the so-called "Kigali Amend - the greenhouse effect. On top of that there ranges and lubricant specifications, see ment" was adopted in 2016 under the is the direct global warming potential (GWP) pages 42 to 45. due to refrigerant emission. Montreal Protocol, in which a step-by-step For reasons of clarity the less or only reduction of HFCs ("HFC phase-down") was Therefore a calculation method has been regionally known products are not specified agreed upon starting in 2019. developed for the qualified evaluation of a in this issue, which is not intended to imply Even though indirect emissions caused by system which enables an analysis of the any inferiority. energy production are considerably higher total influence on the greenhouse effect. 3 Alternative refrigerants – overview

Alternative Refrigerants

Transitional/Service Medium and Long Refrigerants* Term Refrigerants

HCFC/HFC HFC "Low GWP " Halogen free – partly chlorinated – – chlorine free – Refrigerants

Single Single Single Single Substances Blends Substances Blends Substances Blends Substances Blends

e.g.. R22 predominantly e.g. R134a e.g. R404A R1234yf R1234yf/ e.g. NH 3 e.g. R600a/ R123 R22 -Based R125 R507A R1234ze(E) R1234ze(E)/ R290 R290 R124 R32 R407-Serie HFKW R1270 R290/ R142b R143a R410A R600a R170 R152a R417A/B R170 R422 A/D R744 R723 R427A * Service refrigerants contain HCFC as blend component. They are therefore subject to the same legal regulations as R22 (see page 8). As a result of the continued refurbishment of older installations, the importance of these refrigerants is clearly on the decline. For some of them, production has already been discontinued. However, because of the development history of service blends, these refrigerants will continue to be covered in this Report. Fig. 1 Structural classification of refrigerants

HFC refrigerants 09.20

Former Alternatives Refrigerants

ASHRAE Trade name Composition Detailed Classification (with blends) Information R 1 2 R134a – – R152a 1 – – pages (R500) 4 9...12, 16, 42...44 R437A ISCEON ® MO49 Plus Chemours R125/134a/600/601 R404A various R143a/125/134a R22/R502 R507A various R143a/125 pages R422A ISCEON ® MO79 Chemours R125/134a/600a 17...19, 42...44 R407A – Koura (Mexichem), Arkema R32/125/134a R407C various R32/125/134a R407F Performax ® LT Honeywell R32/125/134a R407H – Daikin Chemical R32/125/134a R410A various R32/125 R22 R417A ISCEON ® MO59 Chemours R125/134a/600 pages R417B – Daikin Chemical R125/134a/600 18...23, 42...44 R422D ISCEON ® MO29 Chemours R125/134a/600a R427A Forane ® 427A Arkema R32/125/143a/134a R438A ISCEON ® MO99 Chemours R32/125/134a/600/601a R114 R236fa – – pages R12B1 R227ea – – 37, 41...43 R13B1 R410A various R32/125 pages 39, 42...44 R23 – – R13 pages R508A KLEA ® 508A Koura (Mexichem) R23/116 R503 40, 42...44 R508B Suva ® 95 Chemours R23/116

Tab. 1 Substitutes for CFC and HCFC refrigerants (chlorine free HFCs) 4 Alternative refrigerants – overview

HFO and HFO/HFC Blends 09.20

Current Alternatives Refrigerants

ASHRAE Trade name Composition Detailed Classification (with blends) Information

R1234yf 1 various – R1234ze(E) 1 various – R450A Solstice ® N-13 Honeywell R1234ze(E)/134a pages 24…27, R 1 3 4 a R456A AC5X Koura (Mexichem) R32/1234ze(E)/134a TM XP10 Chemours 42…44 R513A Opteon R1234yf/134a R513A Daikin Chemical R516A ARM-42 Arkema R1234yf/152a/134a

R448A Solstice ® N-40 Honeywell R32/125/1234yf/1234ze(E)/134a TM XP40 Chemours pages 24…27, R 4 0 4 A / R 5 0 7 A * R449A Opteon R32/125/1234yf/134a ( R 2 2 / R 4 0 7 C * ) Forane ® 449 Arkema 42…44 R449C Opteon TM XP20 Chemours R32/125/1234yf/134a

R32 1 various – Opteon TM XL55 Chemours pages 24…27, R410A R452B 1 R32/125/1234yf Solstice ® L-41y Honeywell 42…44 R454B 1 Opteon TM XL41 Chemours R32/1234yf

* Due to the large number of different HFO/HFC blends and the potential changes in development products, the above list contains as alternatives for R134a and R404A/R507A only non-flammable blends of GWP approx. 600 (R134a) and GWP < 1500 (R404A/R507A). For an extensive discussion of HFO/HFC blends: see chapter "Low GWP" HFOs and HFO/HFC blends as alternatives to HFCs, page 24. Further alternatives are also dealt with.

Tab. 2 "Low GWP" refrigerants and blends

Halogen free refrigerants 09.20

Current Alternatives Refrigerants

ASHRAE Trade name Formula Detailed Classification Information

1 R290/600a – C3H8/C 4H10 pages R134a 1 3 R600a – C4H10 30, 42...44

1 2 R717 – NH 3 R404A 1 2 R723 – NH 3 + R-E170 pages R507A 1 R290 – C3H8 28...32, 42...44 R22 1 R1270 – C3H6

pages R124 R600a 1 – C H 4 1 0 37, 42...44

R 4 1 0 A no direct alternatives available

1 pages R23 R170 – C H 2 6 39, 42...44

pages Various R744 3 – CO 2 33...36, 42...44

Tab. 3 Alternatives for HCFC and HFC refrigerants (halogen free refrigerants)

Explanation of Tab. 1 to 3 1 Flammable 2 Toxic 3 Large deviation in refrigerating capacity and 4 Service refrigerant pressures to the previous refrigerant with zero ODP

5 Environmental aspects

Global Warming and Due to a deciding proportion of the total bal - charges, leakage losses and energy con - TEWI Factor ance, there is not only a need for alternative sumptions (example: medium temperature refrigerants with a favorable (thermodynam - with R134a). ic) energy balance, but an increase in de- This example is simplified based on an As already mentioned (see chapter Re- mand for highly efficient compressors overall leak rate as a percentage of the frigerant developments and legal situation, and associated equipment as well as opti - refrigerant charge. The actual values vary page 3), a method of calculation has been mised system components and system con - very strongly, so that the potential risk of developed to judge the influence upon the trol. individually constructed systems and exten - global warming effect for the operation of sively branched plants is especially high. individual refrigeration plants (TEWI = Total When various compressor designs are com - Equivalent Warming Impact). pared, the difference of indirect CO 2 emis - Great effort is taken worldwide to reduce sion (due to the energy requirement) can greenhouse gas emissions, and legal regu - All halocarbon refrigerants (including the have a larger influence upon the total effect lations have partly been developed already. non-chlorinated HFCs) belong to the cat- than the refrigerant losses. Since 2007, the "Regulation on certain fluor- egory of greenhouse gases. An emission of inated greenhouse gases" – which also these substances contributes to the global A usual formula is shown in Fig. 2. The defines stringent requirements for refriger- warming effect. The influence is however TEWI factor can be calculated and the vari - ation and air conditioning systems – has much greater in comparison to CO , which ous areas of influence are correspondingly 2 become valid for the EU. Meanwhile, the is the main greenhouse gas in the atmo - separated. revised Regulation No. 517/2014 entered sphere (in addition to water vapour). Based Additionally, the following figure (Fig. 3) into force and has to be applied since Jan - on a time horizon of 100 years, the emis - shows TEWI values with various refrigerant uary 2015. sion from 1 kg R134a is for example rough - ly equivalent to 1430 kg of CO 2 (GWP = 1430). 7(:, = 727$/(48,9$/(17:$50,1*,03$&7

Thus, the reduction of refrigerant losses 7(:,  *:3[/[Q  *:3[P>˞UHFRYHU\@  Q[( DQQXDO [˟  must be one of the main tasks for the /HDNDJH 5HFRYHU\ORVVHV (QHUJ\FRQVXPSWLRQ future. GLUHFWJOREDOZDUPLQJSRWHQWLDO LQGLUHFWJOREDO On the other hand, the major contributor to ZDUPLQJSRWHQWLDO a refrigeration plant’s global warming effect *:3 *OREDOZDUPLQJSRWHQWLDO >&2UHODWHGDFFWR,3&&,9@ is the (indirect) CO 2 emission caused by / /HDNDJHUDWHSHU\HDU >NJ@ energy generation. Based on the high per - Q 6\VWHPRSHUDWLQJWLPH >NJ@ ˞ 5HF\FOLQJIDFWRU tions, the average European CO 2 release is UHFRYHU\ around 0.365 kg per kWh* of electrical ener - (DQQXDO (QHUJ\FRQVXPSWLRQSHU\HDU >N:K@ gy. This results in a significant greenhouse ˟ &2(PLVVLRQSHUN:K (QHUJ\0L[ effect over the lifetime of the plant. Fig. 2 Method for the calculation of TEWI figures

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, ( ( L[10%] 1 kg // 2.5 kg 5 ( : 1 5 ( * 1 CAP 13.5 kW 7 ( *  < ( 5 < 5/ ,PSDFWRI 5 UHFRYHU\ E 5 kW x 5000 h/a * 5/ 5/ * ORVVHV < β 0.365 kg CO 2/kWh*  < 5/ 5/ α 0.75 // // // ,PSDFWRI OHDNDJH // // η 15 years ORVVHV NJ NJ NJ NJ GWP 1430 (CO 2 = 1) 5HIULJHUDQWFKDUJH>P@ time horizon 100 years

* Average for EU 2019, source: www.carbonfootprint.com Fig. 3 Comparison of TEWI figures (example) 6 Environmental aspects

Eco-Efficiency With this evaluation approach, the entire life higher in the top right quadrant exhibits an cycle of a system is taken into account in increasingly better Eco-Efficiency – and terms of: conversely, it becomes less efficient in the An assessment based on the specific TEWI bottom left sector. value takes into account the effects of glob - o ecological performance in accordance al warming during the operating period of a with the concept of Life Cycle Assess - The diagonals plotted into the system of refrigeration, air conditioning or heat pump ment as per ISO 14040, coordinates represent lines of equal Eco- installation. However, not the entire ecologi- Efficiency. This means that systems or pro - o economic performance by means of a cal and economical aspects are considered. Life Cycle Cost Analysis. cesses with different life cycle costs and environmental impacts can quite possibly But apart from ecological aspects, economi - This means that the overall environmental result in the same Eco-Efficiency. cal aspects are highly significant when eval - impact (including direct and indirect emis - uating technologies and making investment sions), as well as the investment costs, decisions. With technical systems, the operating and disposal costs, and capital reduction of environmental impact frequent - costs are taken into account. ly involves high costs, whereas low costs often have increased ecological conse - The studies also confirm that an increase of quences. For most companies, the invest - Eco-Efficiency can be achieved by investing ment costs are decisive, whereas they are in optimized plant equipment (minimized often neglected during discussions about operating costs). Hereby, the choice of minimizing ecological problems. refrigerant and the associated system tech - nology play an important role. For the purpose of a more objective assess - ment, studies* were presented in 2005 and Eco-Efficiency can be illustrated in graphic * Study 2005: Compiled by Solvay Management Support GmbH and Solvay Fluor GmbH, Hannover, 2010, using the example of supermarket representation (example, see Fig. 5). The together with the Information Centre on Heat Pumps refrigeration plants to describe a concept for results of the Eco-Efficiency evaluation are and Refrigeration (IZW), Hannover. evaluating Eco-Efficiency . It is based on shown on the x-axis in the system of coordi - Study 2010: Compiled by SKM ENVIROS, UK, commissioned by and in cooperation with EPEE the relationship between added value (a nates, whilst the results of the life cycle cost (European Partnership for Energy and Environment). product's economic value) and the resulting analysis are shown on the y-axis. This Both projects were supported by an advisory group environmental impact. shows clearly: A system that is situated of experts from the refrigeration industry.

Concept of Eco-Efficiency

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Fig. 4 Concept of Eco-Efficiency Fig. 5 Example of an Eco-Efficiency evaluation

7 HCFC refrigerants

R22 as transitional refrigerant refrigerant in new systems and for service Special measures have to be adopted purposes due to its ozone depletion poten- therefore, such as two stage compression, tial – although being low. controlled refrigerant injection, additional Although chlorine-free refrigerants, such as cooling, monitoring of discharge gas tem- With regard to components and system R134a and R404A/R507A (Fig. 1 and Tab. perature, limiting the suction gas superheat technology a number of particularities are to 1) have been widely used − but are already and particularly careful installation. follow as well. Refrigerant R22 has approxi - being replaced by alternatives with lower mately 55% higher refrigerating capacity and GWP in the EU for example − R22 is still pressure levels than R12**. The significantly used internationally in many areas, both for higher discharge gas temperature is also a new installations and for retrofitting existing critical factor compared to R12 (Fig. 6) and ones. R502**. Reasons are relatively low investment costs, Similar relationships in terms of thermal load especially compared with R134a systems, are found in the comparison with HFC refriger - * Not allowed for new equipment in Germany and but also its large application range, favour- Denmark since January 1st, 2000 and in Sweden ants R134a, R404A/R507A (pages 9 and 17). as of 1998. able thermodynamic properties and low Since January 1 st , 2001 restrictions apply to the energy requirement. Additionally, R22 and other member states of the EU as well. The meas- components are still widely available, which Resulting design criteria ures concerned are defined in the ODS Regulation 1005/2009 of the EU commision on ozone depleting is not guaranteed everywhere for the alter - Particularly critical – due to the high dis - substances amended in 2009. This regulation also natives. governs the use of R22 for service reasons within charge gas temperature – are low tempera - the entire EU. Despite of the generally favourable proper - ture plants especially concerning thermal Since 2010, phase-out regulations in other coun - ties R22 is already subject to various region - stability of oil and refrigerant, with the dan - tries, such as the USA, are valid. al restrictions* which control the use of this ger of acid formation and copper plating. ** Already banned in most countries.

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8 HFC refrigerants

R134a as substitute for There are also limitations in the application Lubricants for R134a and other HFCs R12 and R22 with low evaporating temperatures to be considered. The traditional mineral and synthetic oils are Comprehensive tests have demonstrated not miscible (soluble) with R134a and other R134a was the first chlorine free (ODP = 0) that the performance of R134a exceeds the - HFCs described in the following and are HFC refrigerant that was tested comprehen - oretical predictions over a wide range of therefore only insufficiently transported sively. It is now used world-wide in many compressor operating conditions. Tempera - around the refrigeration circuit. refrigeration and air conditioning units with ture levels (discharge gas, oil) are even Immiscible oil can settle out in the heat good results. As well as being used as a lower than with R12 and, therefore, sub - exchangers and prevent heat transfer to pure substance, R134a is also applied as a stantially lower than R22 values. There are such an extent that the plant can no longer component of a variety of blends. thus many potential applications in air con - be operated. ditioning and medium temperature refriger- R134a has similar thermodynamic ation plants as well as in heat pumps. Good New lubricants were developed with the properties to R12: heat transfer characteristics in evaporators appropriate solubility and have been in use and condensers (unlike zeotropic blends) for many years. These lubricants are based Refrigerating capacity, energy demand, favour an economical use. on Polyol Ester (POE) and Polyalkylene temperature properties and pressure levels Glycol (PAG). are comparable, at least in air conditioning R134a is also characterized by a compar- and medium temperature refrigeration ably low GWP (1430). Therefore, in view of For further explanations on lubricants see plants. This refrigerant can therefore be future restrictions (for example EU F-Gas chapter “Lubricants for compressors”, page used as an alternative for most former R12 Regulation), the use of this refrigerant will 41. applications. still be possible for quite some time. If required, systems can later be converted For some applications R134a is even pre - relatively easily to non-flammable (A1) ferred as a substitute for R22 , an impor - HFO/HFC alternatives with a GWP of tant reason being the limitations to the use approx. 600 (Tab. 5). of R22 in new plants and for service. How - ever, the lower volumetric refrigerating capacity of R134a (Fig. 9) requires a larger compressor displacement than with R22.

 

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Resulting design and construction Converting existing R12 plants to containing chlorine is found often. These criteria R134a products are released by the influence of the highly polarized mixture of ester oil and Suitable compressors are required for At the beginning this subject was discussed R134a and find their way into the compres - R134a with a special oil charge and adapt - very controversially, several conversion sor and control devices. Conversion should ed system components. The normal metallic methods were recommended and applied. therefore be limited to systems which are in materials used in CFC plants have also Today there is a general agreement on a good condition. been proven with ester oils; elastomers technically and economically matching solu- must sometimes be matched to the chang - tions. Restrictions for R134a in mobile ing situation. This is especially valid for flex - The characteristics of ester oils are very air conditioning (MAC) systems ible hoses where the requirements call for a favourable here: Under certain conditions minimum residual moisture content and low they can be used with CFC refrigerants, An EU Directive on "Emissions from MAC permeability. they can be mixed with mineral oils and tol - systems" bans the use of R134a in new erate a proportion of chlorine up to a few The plants must be dehydrated with particu - systems. Various alternative technologies hundred ppm in an R134a system. lar care and the charging or changing of are already in use. For further explanations lubricant must also be done carefully. In The remaining moisture content has, how - see pages 11 and 36). addition relatively large driers should be ever, an enormous influence. Very thorough provided, which have also to be matched to evacuation (removal of remaining chlorine the smaller molecule size of R134a. and dehydration) is therfore essential, as well as the installation of generously dimen - Supplementary BITZER information Meanwhile, many years of very positive sioned driers. There is doubtful experience concerning the use of R134a experience with R134a and ester oils with systems where the chemical stability (see also https://www.bitzer.de) have been accumulated. For this refrig - was already insufficient with R12 operation erant, BITZER offers an unequalled e.g. with bad maintenance, small drier o Technical Information KT-500 wide range of reciprocating, screw and capacity, high thermal loading. Increased „BITZER refrigeration compressor scroll compressors. deposition of oil decomposition products oils for reciprocating compressors“







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10 HFC refrigerants

Alternatives to R134a R152a – an alternative "Low GWP" HFO refrigerant to R134a (?) R1234yf For mobile air conditioning systems (MAC) with open drive compressors and hose con - R152a is very similar to R134a with regard The ban on the use of R134a in mobile air nections in the refrigerant circuit, the risk of to volumetric refrigerating capacity (approx. conditioning systems within the EU has trig - leakages is considerably higher than with -5%), pressure levels (approx. -10%) and gered a series of research projects. In addi - stationary systems. An EU Directive energy efficiency. Mass flow, vapour density tion to CO 2 technology (see chapter CO 2 in (2006/40/EC) has been passed to reduce and thus also the pressure drop are even mobile air conditioning systems, page 36), direct emissions in this application area. more favourable (approx. -40%). refrigerants with very low GWP values and Within the scope of the Directive, and start- similar thermodynamic properties as R134a R152a has been used for many years as a ing 2011, type approvals for new vehicles have been developed. will only be granted if they use refrigerants component in blends, but not as a single with a global warming potential (GWP) of substance refrigerant till now. Especially In early 2006, two refrigerant mixtures were less than 150. Consequently, this excludes advantageous is the very low global warm- introduced under the names "Blend H" R134a (GWP = 1430) which has been used ing potential (GWP = 124). (Honeywell) and "DP-1" (DuPont). INEOS Fluor followed with another version under so far in these systems. R152a is flammable – due to its low fluorine the trade name AC-1. In the broadest content – and classified in safety group A2. Meanwhile, alternative refrigerants and new sense, all of these refrigerants were blends As a result, increased safety requirements technologies were developed and tested. of various fluorinated molecules. This also involved a closer examination of demand individual design solutions and the use of R152a. safety measures along with the correspond- During the development and test phase it ing risk analysis. became obvious that not all acceptance For quite some time the automotive industry criteria could be met, and thus further For this reason, the use of R152a in mobile has agreed on so-called "Low GWP" refriger- examinations with these blends were dis - air conditioning systems for passenger cars ants. The latter is dealt with as follows. continued. (MAC) has not been implemented yet. Consequently, DuPont (meanwhile CO 2 technology, favored for this application for quite some time, has not been widely Chemours) and Honeywell bundled their implemented for a variety of reasons research and development activities in a (pages 12 and 36). joint venture which focused on 2,3,3,3- tetrafluoropropene (CF 3CF=CH 2). This refrigerant, designated R1234yf, belongs to the group of hydro fluoro olefins (HFO). These refrigerants are unsaturated HFCs with a chemical double bond.

11 HFC refrigerants

The global warming potential is extremely Toxicity investigations have shown very With a view to the relatively simple conver - low (GWP = 4). When released to the atmos- positive results, as well as compatibility sion of mobile air conditioning systems, this phere, the molecule rapidly disintegrates tests of the plastic and elastomer materials technology prevailed up to now over the within a few days, resulting in a very low used in the refrigeration circuit. Some lubri - competing CO 2 systems. GWP. This raises certain concerns regard - cants show increased chemical reactivity However, as already explained before, due ing the long-term stability in refrigeration cir - which, however, can be suppressed by a to the flammability of R1234yf, investiga - cuits under real conditions. suitable formulation and/or addition of tions focus on other technical solutions. However, extensive testing has demonstrat - "stabilizers". This includes active fire-extinguishing de- ed the required stability for mobile air condi - Operating experiences gained from labora - vices (e.g. with argon), but also enhance - tioning systems. tory and field trials to date allow a positive ments of CO 2 systems. R1234yf has lower flammability as meas- assessment, particularly with regard to per - For detailed information on properties and ured by ASTM 681, but requires signifi- formance and efficiency behaviour. For the the application, see chapter "Low GWP" cantly more ignition energy than R152a, for usual range of mobile air conditioning oper - HFOs and HFO/HFC blends as alternatives instance. Due to its low burning velocity and ation, refrigerating capacity and coefficient to HFCs, page 24. the high ignition force, it received a classifi - of performance (COP) are within a range of cation of the new safety group "A2L" ac- 5% compared with that of R134a. There - cording to ISO 817. fore, it is expected that simple system mod - In extensive test series, it has been shown ifications will provide the same performance that a potentially increased risk of the refrig - and efficiency as with R134a. erant flammability in MAC systems can be The critical temperature and pressure lev - avoided by implementing suitable construc - els are also similar, while the vapour densi - tive measures. However, some investiga - ties and mass flows are approximately 20% tions (e.g. by Daimler) also show an in- higher. The discharge gas temperature with creased risk. This is why various manu- this application is up to 10 K lower. facturers have intensified again the devel - opment of alternative technologies.

12 Refrigerant blends

Refrigerant blends "azeotropes" (e.g. R502, R507A) with ther - BITZER has accumulated extensive modynamic properties similar to single sub - experience with refrigerant blends. stance refrigerants, and "zeotropes" with Laboratory and field testing was com - Refrigerant blends have been developed for "gliding" phase changes (also see next menced at an early stage so that basic existing as well as for new plants with pro - chapter). The original development of information was obtained for the opti - mizing of the mixing proportions and perties making them comparable alternatives "zeotropes" mainly concentrated on special for testing suitable lubricants. Based to the previously used substances. applications in low temperature and heat on this data, a large supermarket plant pump systems. Actual system construction, It is necessary to distinguish between three – with 4 BITZER semi-hermetics in par - however, remained the exception. categories: allel – could already be commissioned A somewhat more common earlier practice in 1991. The use of these blends in the 1. Transitional or service blends most varied systems has been state-of- was the mixing of R12 to R22 in order to which mostly contain HCFC R22 as the the-art for many years – generally with improve the oil return and to reduce the dis - main constituent. They are primarily good experiences. charge gas temperature with higher pres - intended as service refrigerants for sure ratios. It was also usual to add R22 to older plants with view on the use ban of General characteristics of zeotropic R12 systems for improved performance, or R12, R502 and other CFCs. Correspond - blends to add hydrocarbons in the extra low tem - ing products are offered by various manu - perature range for a better oil transport. As opposed to azeotropic blends (e.g. facturers, there is practical experience R502, R507A), which behave as single sub - covering the necessary steps of conver - This possibility of specific "formulation" of stance refrigerants with regard to evapora - sion procedure. certain characteristics was indeed the basis tion and condensing processes, the phase for the development of a new generation of However, the same legal requirements as change with zeotropic fluids occurs in a blends. for R22 apply to the use and phase-out of "gliding" form over a certain range of tem - these blends (see page 8). At the beginning of this Report (see chapter perature. Refrigerant developments and legal situa - 2. HFC blends This "temperature glide" can be more or tion, page 3) it was already explained that These are substitutes for the refrigerants less pronounced, it depends mainly on the no direct single-substance alternatives (on R502, R22, R13B1 and R503. Above all, boiling points and the percentage propor - the basis of fluorinated hydrocarbons) exist R404A, R507A, R407C and R410A, are tions of the individual components. Certain for the previously used and current refriger - being used to a great extent. supplementary definitions are also used, ants of higher volumetric refrigeration cap- One group of these HFC blends also con - depending on the effective values, such as acity than R134a. This is why they can only tains hydrocarbon additives. The latter "near-azeotrope" or "semiazeotrope" for be "formulated" as blends. However, taking exhibit an improved solubility with lubri - less than 1 K glide. into account thermodynamic properties, cants, and under certain conditions they flammability, toxicity and global warming Essentially, this results in a small tempera - allow the use of conventional oils. In many potential, the list of potential candidates is ture increase already in the evaporation cases, this permits the conversion of exist - strongly limited. phase and a reduction during condensing. ing (H)CFC plants to chlorine-free refriger - In other words: At a certain pressure level, ants (ODP = 0) without the need for an oil For the previously developed CFC and the resulting saturation temperatures differ change. HCFC substitutes, the range of substances in the liquid and vapour phases (Fig. 11). was still comparably large, due to the fact 3. HFO/HFC blends that substances of high GWP could also be To enable a comparison with single sub - as successor generation of HFC refriger - used. However, for formulating blends with stance refrigerants, the evaporating and ants. It concerns blends of new "Low significantly reduced GWP, in addition to condensing temperatures have been often GWP" refrigerants (e.g. R1234yf) with R134a, R1234yf and R1234ze(E), primarily defined as mean values. As a consequence HFCs. The fundamental target is an addi - refrigerants R32, R125 and R152a can be the measured subcooling and superheating tional decrease of the global warming po- used. Most of them are flammable. They conditions (based on mean values) are tential (GWP) as compared to established also exhibit considerable differences with unrealistic. The effective difference – based halogenated substances (see page 24). respect to their boiling points, which is why on dew and bubble temperature – is less in Blends of two and three components already all "Low GWP" blends of high volumetric each case. These factors are very important have a long history in the refrigeration trade. refrigerating capacity have a substantial when assessing the minimum superheat at A difference is made between the so called temperature glide (see next chapter). the compressor inlet (usually 5 to 7 K) and the quality of the refrigerant after the liquid receiver (vapour bubbles).

13 Refrigerant blends





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With regard to a uniform and easily compre - the pure gas and liquid phases is mainly o The plant always has to be charged with hensible definition of the rated compressor non-critical. Leaks in the phase change liquid refrigerant. When vapour is taken capacity, the revised standards EN 12900 areas, e.g. after the expansion valve, within from the charging cylinder, concentration and AHRI540 are applied. Evaporating and the evaporator and condenser/receiver are shifts may occur. condensing temperatures refer to saturated considered more significant. It is therefore o Since all blends contain at least one conditions (dew points). recommended that soldered or welded flammable component, the entry of air joints should be used in these sections. o Evaporating temperature according to into the system must be avoided. If the point A (Fig. 11) Extended investigations have shown in the proportion of air is too high, a critical shift o Condensing temperature according to meantime that leakage leads to less serious of the ignition point can occur under high point B (Fig. 11) changes in concentration than initially pressure and while evacuating. thought. In any case it is certain that the fol - In this case the assessment of the effective lowing substances of safety group A1 (see o The use of blends with a significant tem - superheat and subcooling temperatures will page 42) which are dealt with here cannot perature glide is not recommended for be simplified. develop any flammable mixtures, either plants with flooded evaporators. A large concentration shift is to be expected in It must however be considered that the inside or outside the circuit. Essentially sim - this type of evaporator, and as a result actual refrigerating capacity* of the system ilar operating conditions and temperatures also in the circulating refrigerant mass can be higher than the rated compressor as before can be obtained by supplemen - flow. capacity. This is partly due to an effectively tary charging with the original refrigerant in lower temperature at the evaporator inlet. the case of a small temperature glide. * In the new edition (2020) of the standard for condens- ing units EN13215, the declaration of performance A further characteristic of zeotropic refriger - Further conditions/recommendations con - data based on the mean evaporating temperature has also been included. This enables a direct com - ants is the potential concentration shift cerning the practical handling of blends parison with performance data for single-component when leakage occurs. Refrigerant loss in must also be considered: refrigerants.

14 Service blends

Service blends with the basic as hydrocarbons have especially good solu - Resulting design criteria/ component R22* as substitutes bility characteristics. Converting existing R502 plants for R502 For these blends two variations are offered The compressor and the components which in each case. When optimizing the blend are matched to R502 can remain in the sys - As a result of the continued refurbishment variations with regard to identical refriger- tem in most cases. The limitations in the of older installations, the importance of ating capacity as for R502 the laboratory application range must however be consid - these refrigerants is clearly on the decline. measurements showed a significantly in- ered: Higher discharge gas temperature For some of them, production has already creased discharge gas temperature (Fig. 13), than R502 with R402B**, R403A** and been discontinued. However, because of which above all, with higher suction gas R408A** or higher pressure levels with the development history of service blends, superheat (e.g. supermarket use) leads to R402A** and R403B**. these refrigerants will continue to be cover- limitations in the application range. The good solubility characteristics of R22 ed in this Report. On the other hand a higher proportion of and R290 increase the risk that, after con - These refrigerants belong to the group of R125 or R218, which has the effect of re- version of the plant, possible deposits of oil "Service blends" and have been offered ducing the discharge gas temperature to the decomposition products containing chlorine under the designations R402A/R402B* level of R502, results in somewhat higher are dissolved and find their way into the (HP80/HP81 – DuPont), R403A/R403B* refrigerating capacity (Fig. 14). compressor and control devices. Systems (formerly ISCEON ® 69S/69L) and R408A* where chemical stability was already insuf- With regard to material compatibility the (“Forane ®” FX10 – Arkema). ficient with R502 operation (bad mainte - blends can be judged similarly to (H)CFC nance, low drier capacity, high thermal The basic component is in each case R22, refrigerants. The use of conventional re- loading) are particularly at risk. the high discharge gas temperature of frigeration oil (preferably semi or full syn- which is significantly reduced by the addi - thetic) is also possible due to the R22 and Thus, generously dimensioned suction gas tion of chlorine free substances with low R290 proportions. filters and liquid line driers should be in- isentropic compression exponent (e.g. stalled for cleaning before conversion, and Apart from the positive aspects there are R125, R143a, R218). A characteristic fea- an oil change should be made after approxi - also some disadvantages. These substan - ture of these additives is an extraordinarily mately 100 hours operation. Further checks ces are alternatives only for a limited time. high mass flow, which enables the mixture are recommended. The R22 proportion has (although low) an to achieve a great similarity to R502. ozone depletion potential. Furthermore, the R290 (Propane) is added as the third com - additional components R125, R143a and * When using blends containing R22, legal regula - ponent to R402A/B and R403A/B to im- R218 have a high global warming potential tions are to be observed, see page 8. prove miscibility with traditional lubricants (GWP). ** Classification according to ASHRAE nomenclature.

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The operating conditions with R502 (includ - A further service blend was offered under Resulting design criteria/ ing discharge gas temperature and suction the designation R413A (ISCEON ® 49 – Converting existing R12 plants gas superheat) should be noted so that a DuPont), but replaced by R437A by the end Compressors and components can mostly comparison can be made with the values of 2008. However, because of the develop - remain in the system. However, when using after conversion. Depending upon the ment history of service blends, R413A will R413A and R437A the suitability must be results, control devices should possibly be continue to be covered in this Report. The checked against HFC refrigerants. The reset and other additional measures should constituents of R413A consist of the chlor- actual "retrofit" measures are mainly re- be taken as required. ine free substances R134a, R218, and stricted to changing the refrigerant (possibly R600a. In spite of the high R134a content, oil) and a careful check of the superheat the use of conventional lubricants is pos- setting of the expansion valve. sible because of the relatively low polarity of R218 and the favourable solubility of A significant temperature glide is present R600a. due to the relatively large differences in the boiling points of the individual substances, Service blends as R437A is a blend of R125, R134a, R600 which requires an exact knowledge of the substitutes for R12 (R500) and R601 with similar performance and saturation conditions (can be found from properties as R413A. This refrigerant is also vapour tables of refrigerant manufacturer chlorine-free (ODP = 0). Although (as experience already shows) and in the BITZER Refrigerant App) in order R134a is also well suited for the conversion However, due to the limited miscibility of to assess the effective suction gas super - of existing R12 plants, the general use for R413A and R437A with mineral and alkyl - heat. such a "retrofit" procedure is not always benzene oils, oil migration may result in In addition the application range must also possible. Not all compressors which have systems with a high oil circulation rate be observed. Different refrigerant types are previously been installed are designed for and/or a large liquid volume in the receiver required for high and low evaporating tem - the application with R134a. In addition a – for example if no oil separator is installed. conversion to R134a requires the possibility peratures or distinct capacity differences to make an oil change, which is for example If insufficient oil return to the compressor is must be considered. This is due to the not the case with most hermetic type com - observed, the refrigerant manufacturer steeper capacity characteristic, compared to pressors. recommends replacing part of the original R12. oil charge with ester oil. But from the com - Due to the partially high proportion of R22 Economical considerations also arise, espe - pressor manufacturer's view, such a meas- especially with the low temperature blends, cially with older plants where the effort of ure requires a very careful examination of the discharge gas temperature with some converting to R134a is relatively high. The the lubrication conditions. For example, if refrigerants is significantly higher than with chemical stability of such plants is also increased foam formation in the compressor R12. The application limits of the compres - often insufficient and thus the chance of crankcase is observed, a complete change sor should therefore be checked before success is very questionable. to ester oil will be necessary. Moreover, converting. Therefore "Service blends" are also avail- under the influence of the highly polarized able for such plants as an alternative to R134a blend of ester oil and HFC, the admixture of The remaining application criteria are simi - and are offered under the designations or conversion to ester oil leads to increased lar to those for the substitute substances for R401A/R401B, R409A. The main compo - dissolving of decomposition products and R502 which have already been mentioned. nents are the HCFC refrigerants R22, R124 dirt in the pipework. Therefore, generously and/or R142b. Either HFC R152a or R600a dimensioned suction clean-up filters must (Isobutane) is used as the third component. be provided. For further details, see the Operation with traditional lubricants (prefer - refrigerant manufacturer's "Guidelines". ably semi or full synthetic) is also possible * By using R22 containing blends the legal require - ments are to be followed, see chapter R22 as tran - due to the major proportion of HCFC. sitional refrigerant, page 8.

16 Substitutes for R22 in refrigeration systems

R404A and R507A as R134a, the temperature glide with the ter - the TEWI value. Other improvements are substitutes for R22 and R502 nary blend R404A within the relevant appli - possible in this respect due to further de- cation range is less than one Kelvin. The veloped system control. characteristics within the heat exchangers Nevertheless, due to their high global warm- These blends are chlorine free substitutes are therefore not very different than with ing potential (GWP), the use of R404A and (ODP = 0) for R22 as well as for R502 in azeotropes. The results obtained from heat R507A is no longer allowed in the EU in medium and low temperature ranges. transfer measurements show favourable new installations since 2020. This has been conditions. A composition which was already launched settled in the F-Gas Regulation No. at the beginning of 1992 is known under the R507A is a binary substance combination 517/2014 to be applied since 2015. How- trade name Suva ® HP62 (DuPont). Long which even gives an azeotropic characteri - ever, the current requirement of phase-down term use has shown good results. Further stic over a relatively wide range. The condi - in connection with a strict quota system has blends were traded as Forane ® FX70 tions therefore tend to be even better. already led to an earlier phase-out in many (Arkema) and Genetron ® AZ50 (Allied Sig - applications. For more detailed information, The performance (Fig. 16) gives hardly any nal/ Honeywell) or Solkane ® 507 (Solvay). please refer to BITZER brochure A-510. difference between the various substances HP62 and FX70 have been listed in the and ist very similar to R502. This also In the USA, Canada and Australia there are ASHRAE nomenclature as R404A and explains the high market penetration of also requirements to phase-out R404A and AZ50 as R507A. these refrigerants. With regard to the ther - R507A. For an international phase-down The basic components belong to the HFC modynamic properties, they are particularly (since 2019) of HCFC and HFC refriger- group, where R143a belongs to the flam- suitable for commercial medium and low ants, the so-called Kigali Amendment was mable category. Due to the combination temperature systems. agreed upon in 2016 as part of the Montreal with a relatively high proportion of R125 Protocol. Typical metallic materials are compatible the flammability is effectively counteracted, with HFC refrigerants. Elastomers, however, Alternatives with lower GWP are the HFC even in the case of leakage. must be adapted to the changed character- blends explained in the following as well as A feature of all three ingredients is the very istics. Suitable lubricants are polyol esters the newly developed HFO/HFC blends low isenropic compression exponent which (see chapter Lubricants for compressors, (from page 24). results in a similar, with even a tendency to page 41). Halogen free refrigerants or cascade be lower, discharge gas temperature to The relatively high global warming potential systems using different refrigerants are R502 (Fig. 15). The efficient application of (GWP = 3922 .. 3985), which is mainly also an option for specific applications single stage compressors with low evaporat- determined by the R143a and R125, is (from page 28). ing temperatures is therefore guaranteed. something of a hitch. However, it is better Due to the similar boiling points for R143a than R502 and with regard to the favourable and R125, with a relatively low proportion of energy demand also leads to a reduction of @ . > 

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Resulting design criteria R407A/407B/407F/407H as the isentropic compression exponent is substitutes for R22 and R502 even higher than with R22. Rather high pro - The system technology can be based on portions of R125 and R134a are necessary the experience with R22 and R502 over a to match the characteristics at the level of wide area. As an alternative to the earlier described R404A and R507A. The flammability of R32 substitutes, additional mixtures have been On the thermodynamic side, a heat ex- is thus effectively suppressed, but the large developed based on R32 which is chlorine changer between the suction and liquid differences in boiling points with a high pro - free (ODP = 0) and flammable like R143a. line is recommended as this will improve portion of R134a lead to a larger tempera- The refrigerant R32 is also of the HFC type the refrigerating capacity and COP. ture glide. and initially was regarded as a main candi - date for R22 alternatives (page 20). How- The main advantage of R32 is the relatively BITZER offers the whole program of ever, due to extent of blend variations com - low global warming potential (GWP = 675), reciprocating, scroll and screw com - parable thermodynamic characteristics to so that even in combination with R125 and pressors for R404A and R507A. R404A/R507A can also be obtained. R134a it is significantly lower than with the R143a based alternatives mentioned above Supplementary BITZER information con - These kind of refrigerants were marketed at (R407A: GWP = 2107, R407F: GWP = ® cerning the use of HFC blends first under the trade name KLEA 60/61 1825, R407H: GWP = 1490). (see also https://www.bitzer.de) (ICI) and are listed as R407A/R407B* in the ASHRAE nomenclature. Thus, they also comply with the require - o Technical Information A-540 ment of the new EU F-Gas Regulation „Retrofit R22 or R404A/R507A – Honeywell has developed another blend which from 2020 will only allow refrigerants Step by step” with the trade name Performax ® LT (R407F of GWP < 2500. o Technical Information KT-500 according to ASHRAE nomenclature) and „BITZER refrigeration compressor introduced it into the market, similar Daikin Measurements made with R32 containing oils for reciprocating compressors“ Chemical with R407H. For both blends, the blends do show certain capacity reductions R32 proportion is higher than for R407A, compared to R404A and R507A, with low while the R125 proportion is lower. With evaporating temperatures. The COP how- R407H, this results in certain restrictions for ever shows less deviation and is even higher low temperature applications. in medium temperature applications (Fig. 18). However, the necessary conditions for alter - natives containing R32 are not quite as * Meanwhile, R407B is no longer available in the mar - favourable compared to the R143a based ket. Due to the historical development of HFC blends this refrigerant will, however, still be considered in substitutes discussed earlier. The boiling this Report. point of R32 is very low at -52°C, in addition 

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18 Substitutes for R22 in refrigeration systems

Whether these favourable conditions are pipework. Therefore, generously dimen - The material compatibility is comparable to confirmed in real applications is subject to sioned suction clean-up filters must be pro - the blends mentioned previously, the same the system design. An important factor is vided. applies to the lubricants. On account of the the significant temperature glide, which can good solubility of R600a, conventional lubri - have a negative influence upon the capac- Conversion of existing R404A/R507A cants can also be used under favourable ity/temperature difference of the evaporator systems to R407A/407B/407F/407H circumstances. and condenser. Larger differences in thermodynamic prop - In particular, advantages result during the With regard to the material compatibility, erties (e.g. mass flow, discharge gas tem - conversion of existing R22 and R502 R32 blends can be assessed similarly to perature) and the temperature glide of systems as mentioned above. However, for R404A and R507A; the same applies to the R407A/F/H may require the replacement of plants with high oil circulation rates and/or lubricants. control components and if necessary large liquid charge in the receiver, oil migra - retrofitting of additional compressor cooling tion might occur – for example if no oil Despite the relatively high proportion of when existing systems are converted. separator is installed. R125 and R134a in the R32 blends, the dis - For newly built systems, a specific design charge gas temperature is higher than with If insufficient oil return to the compressor is of components and system is necessary. the R143a based alternatives (especially for observed, the refrigerant manufacturer R407F and even to a higher degree with recommends replacing part of the original BITZER offers a comprehensive program R407H). This results in certain limitations in oil charge with ester oil. But from the com - of reciprocating and screw compressors the application range as well as the require - pressor manufacturer's view, such a meas- for R407A and R407F. An individual ment for additional cooling of compressors ure requires a very careful examination of selection of compressors for R407H is when operating at high pressure ratios. the lubrication conditions. For example, if in- possible upon demand. creased foam formation in the compressor 2-stage compressors can be applied very crankcase is observed, a complete change efficiently where especially large lift condi - to ester oil* will be necessary. Under the tions are found. An important advantage in R422A as substitute influence of the highly polarized blend of this case is the use of a liquid subcooler. for R22 and R502 ester oil and HFC, the admixture of or con - version to ester oil leads to increased dis - Resulting design criteria Amongst other aims, R422A (ISCEON ® solving of decomposition products and dirt The experience with R404A/R507A and MO79 – Chemours) was developed in order in the pipework. Therefore, generously R22 can be used for plant technology in to obtain a chlorine-free refrigerant (ODP = 0) dimensioned suction clean-up filters must many respects, although the temperature for the simple conversion of existing me- be provided. For further details, see the glide as well as the difference in the ther - dium and low temperature refrigeration refrigerant manufacturer's "Guidelines". modynamic properties have to be consid - systems using R22 and R502. From a thermodynamic point of view, a heat ered. This especially concerns the design exchanger between suction and liquid line and construction of heat exchangers and For this, it was necessary to formulate a is recommended, improving the refrigerating expansion valves. refrigerant with comparable performance and energy efficiency to that of R404A, capacity and coefficient of performance. Be- R507A, and R22, which also permits the sides this the resulting increase in operat- Converting existing R22 plants to use of conventional lubricants. ing temperatures leads to more favourable R407A/407B/407F/407H lubricating conditions (lower solubility). R422A is a zeotropic blend of the basic Practical experiences show that qualified components R125 and R134a with a small Due to the high global warming potential conversions are possible. Compared to R22 addition of R600a. Due to its relatively high (GWP ≥ 2500), R422A will no longer be the volumetric refrigeration capacity is near - R134a percentage, the temperature glide allowed for new installations in the EU from ly similar while the refrigerant mass flow is (see chapter Refrigerant Properties, page 2020 onwards. The requirements and re- only slightly higher. These are relatively 42) lies higher than for R404A, but lower strictions are specified in the F-Gas Regula - favourable conditions for the conversion of than other refrigerants with the same com - tion 517/2014. medium and low temperature R22 systems. ponent blends – such as R417A and R422D * General proposal for screw compressors and liquid The main components can remain in the (see page 22). chillers when used with DX evaporators with internal - system provided that they are compatible ly structured heat exchanger tubes. Furthermore, an The adiabatic exponent, and therefore also with HFC refrigerants and ester oils. individual check regarding possible additional meas- the discharge gas and oil temperatures of the ures will be necessary. However, special requirements placed on compressor, are lower than for R404A and BITZER compressors are suitable for the heat exchanger with regard to the signif - R507A. At extremely low temperatures, this R422A. An individual selection is pos- icant temperature glide must be considered. can be advantageous. However, in cases of sible upon demand. A conversion to ester oil is also necessary, low pressure ratio and suction gas super- which leads to increased dissolving of de- heat, this can be a disadvantage due to in- composition products and dirt in the creased refrigerant solution if ester oil is used.

19 Substitutes for R22 in A/C and heat pumps

Substitutes for R22 in air condi - R407C as substitute Thus, R407C also complies with the re- tioning systems and heat pumps for R22 quirement of the new EU F-Gas Regula- tion which from 2020 onwards will only allow refrigerants with GWP < 2500. How - As the HCFC refrigerant R22 (ODP = 0.05) Mixtures of HFC refrigerants R32, R125 and ever, the quantity limitation through the is accepted only as a transitional solution, a R134a were considered to be the preferred "phase-down" will also lead to significantly number of chlorine-free (ODP = 0) alterna- candidates for short-term substitutes for restricted availability. tives have been developed and tested exten - R22 in the EU in view of the early ban of The high temperature glide is a disadvan - sively. They are being used for a large R22. Performance values and efficiency are tage for usual applications which requires range of applications. highly comparable (Fig. 19). At first two blends of the same composition appropriate system design and can have a Experience shows, however, that none of have been introduced under the trade negative influence on the efficiency of the these substitutes can replace the refrigerant names AC9000* (DuPont) and KLEA ® 66* heat exchangers (see chapter General char - R22 in all respects. Amongst others there (ICI). They are listed in the ASHRAE nomen- acteristics of zeotropic blends, page 13). are differences in the volumetric refrigerating clature as R407C. In the meantime there Due to the properties mentioned, R407C is capacity, restrictions in possible applications, are also further blend varieties (e.g. R407A/ preferably an R22 substitute for air condi - special requirements in system design and R407F/R407H) with somewhat differing tioning and heat pump systems and (within considerably differing pressure levels. composi tions, whose properties have been certain limitations) also for medium tem- According to the specific operating conditions, optimized for particular applications (see perature refrigeration. In low temperature various alternatives may be considered. page 18). refrigeration, because of the high proportion Apart from the single-component HFC re- Unlike the substitutes for R22 in refriger- of R134a, a significant drop in refrigerating frigerant R134a, these are mainly blends ation systems with identical blend compo - capacity and COP is to be expected. There (different compositions) of the components nents (pages 18 and 19), the substitutes for is also the danger of an increased R134a R32, R125, R134a, R143a, and R600(a). R22 in air conditioning systems and heat concentration in the blend in evaporators, The following description mainly concerns pumps under consideration contain higher with reduced performance and malfunction - the development and potential applications proportions of R32 and R134a. A good cor - ing of the expansion valve (e.g. insufficient of these. The halogen-free substitutes NH 3, respondence with the properties of R22 in suction gas superheat). propane and propylene as well as CO 2 terms of pressure levels, mass flow, vapour Material compatibility is similar to that of the should also be considered, however, spe- density and volumetric refrigerating capacity blends discussed previously; the same ap- cific criteria must be applied for their use is thus achieved. In addition, the global plies to lubricants. (description from page 28). warming potential is relatively low (GWP = In addition, R32 and HFO/HFC blends can 1774). * Previous trade names are not used any more. also be used as alternatives (see chapter R32 as substitute for R22 and HFO/HFC blends, from page 23).

 

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Resulting design criteria R410A as substitute for R22 Because of the negligible temperature glide (< 0.2 K), the general usability is similar to With regard to system technology, previous that of a pure refrigerant. experience with R22 can only be utilized to In addition to R407C, the near-azeotropic a limited extent. mixture listed by ASHRAE as R410A is The material compatibility is comparable to available and widely used for medium-sized the previously discussed blends, the same The distinctive temperature glide requires a capacities in air conditioning and heat pump applies to the lubricants. However, the pres - particular design of the main system com - applications. sure levels and the higher specific loads on ponents, e.g. evaporator, condenser, ex- the system components need to be taken pansion valve. In this context it must be An essential feature indicates nearly 50% into account. considered that heat exchangers should higher volumetric refrigerating capacity (Fig. preferably be laid out for counterflow opera - 21) compared to R22, but with the conse - Resulting design criteria tion and with optimized refrigerant distribu - quence of a proportional rise in system tion. There are also special requirements pressures (Fig. 22). The fundamental criteria for HFC blends also apply to the system technology with with regard to the adjustment of control At high condensing temperatures, energy R410A. However, the high pressure levels devices and service handling. consumption/COP initially seems to be less have to be considered (43°C condensing Furthermore, the use in systems with flood - favourable than with R22. temperature already corresponds to 26 bar ed evaporators is not recommended as this This is mainly due to the thermodynamic abs.). would result in a severe concentration shift properties. On the other hand, very high Compressors and other system components and layer formation in the evaporator. isentropic efficiencies are achievable (with designed for R22 are not suitable for this reciprocating and scroll compressors), so refrigerant (or only to a limited extent). BITZER can supply a widespread range that the real differences are lower. of semi-hermetic reciprocating, screw Though, suitable compressors and system and scroll compressors for R407C. Another aspect are the high heat transfer components are available. coefficients in evaporators and condensers Converting existing R22 plants to R407C determined in numerous test series, result- When considering to cover usual R22 appli - ing in especially favourable operating con- cation ranges, the significant differences in Because of the above mentioned criteria, ditions. With an optimized design, it is quite the thermodynamic properties (e.g. pres - no general guidelines can be defined. Each possible for the system to achieve a better sure levels, mass and volume flow, vapour case must be examined individually. overall efficiency than with other refriger- density) must be taken into account. This ants. also requires considerable constructional

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Fig. 21 R410A/R22 – comparison of performance data of a semi-hermetic Fig. 22 R410A/R22 – comparison of pressure levels compressor 21 Substitutes for R22 in A/C and heat pumps changes to compressors, heat exchangers, hydrocarbon additive. It is offered under R427A as a substitute for R22 and controls, as well as measures of tuning trade name ISCEON ® MO29 (Chemours) vibrations. There are stricter safety require - and listed as R422D in the ASHRAE This refrigerant blend was introduced some ments, e.g. affecting the quality and dimen - nomenclature. years ago under the trade name Forane ® sions of piping and flexible tube elements Another refrigerant belonging to the catego - FX100 (Arkema) and is now listed in the (for condensing temperatures of approx. ry of HFC/HC blends was introduced in ASHRAE nomenclature as R427A. 60°C/40 bar). 2009 under the trade name ISCEON ® The R22 substitute is offered for the conver - Another criterion is the relatively low critical MO99 (Chemours) – ASHRAE classifi- sion of existing R22 systems for which a temperature of 71°C. Irrespective of the cation R438A. This formulation was de- "zero ODP" solution is requested. It is an design of components on the high pressure signed especially for a higher critical tem - HFC mixture with base components side, the condensing temperature is thus perature for applications in hot climate R32/R125/R143a/R134a. limited. areas. The base components are R32, R125, R134a, R600 and R601a. In spite of the blend composition based on R410A complies with the requirements of pure HFC refrigerants, the manufacturer the EU F-Gas Regulation, which will only Like R407C, all four substitute refrigerants states that a simplified conversion proced- allow refrigerants with GWP < 2500 from are zeotropic blends with a more or less ure is possible. 2020 onwards. However, the quantity limi- significant temperature glide. In this re- tation through the "phase-down" will also spect, the criteria described for R407C This is facilitated by the R143a proportion. lead to significantly restricted availability. also apply here. Accordingly, when converting from R22 to Due to the extremely high demand for R427A, all it takes is a replacement of the Apart from a similar refrigeration capacity, R410A, a timely switch to alternatives is original oil charge with ester oil. Additional there are nevertheless fundamental differ - needed in the EU. flushing sequences are not required, as ences in thermodynamic properties and in proportions of up to 15% of mineral oil oil transport behaviour. The high proportion For R410A, BITZER offers a series of and/or alkyl benzene have no significant of R125 causes a higher mass flow with semi-hermetic reciprocating compres - effect on oil circulation in the system. R417A/B and R422D than with R407C, a sors and scroll compressors. lower discharge gas temperature and a However, it must be taken into account that relatively high superheating enthalpy. These the highly polarized mixture of ester oil and properties indicate that there are differences HFC will lead to increased dissolving of in the optimization of system components, decomposition products and dirt in the pipe - R417A/417B/422D/438A and a heat exchanger between liquid and work. Therefore, generously dimensioned as substitutes for R22 suction lines is of advantage. suction clean-up filters must be provided. Despite the predominant proportion of HFC Regarding refrigerating capacity, pressure Similar to the development of R422A (page refrigerants, conventional lubricants can be levels, mass flow and vapor density, R427A 19), one aim of developing these blends used to some extent because of the good is relatively close to R22. During retrofit, was to provide chlorine-free refrigerants solubility of the hydrocarbon constituent. essential components such as expansion (ODP = 0) for the simple conversion of However, in systems with a high oil circula - valves can remain in the system. Due to the existing R22 plants. tion rate and/or a large volume of liquid in high proportion of blend components with R417A was introduced to the market years the receiver, oil migration may result. low adiabatic exponent, the discharge gas ago, and is also offered under the trade temperature is considerably lower than with In such cases, additional measures are name ISCEON ® MO59 (Chemours). This R22, which has a positive effect at high necessary. For further information on oil substitute for R22 contains the blend com - compression ratios. return and lubricants see chapter “R422A ponents R125/R134a/R600 and therefore as substitute for R22 and R502” (page 19). It must be taken into account that this is differs considerably from e.g. R407C with a also a zeotropic blend with a distinct tem- Due to the high global warming potential correspondingly high proportion of R32. perature glide. Therefore the criteria de- (GWP ≥ 2500), R417B and R422D will no Meanwhile, a further refrigerant based on scribed for R407C apply here as well. longer be allowed for new installations in identical components, but with a higher the EU from 2020. The requirements and R125 content, has been offered under the restrictions are specified in the F-Gas Reg - ASHRAE designation R417B. Due to its ulation 517/2014. However, the "phase- lower R134a content, its volumetric refriger - down" quantity limitation will also lead to ating capacity and pressure levels are high - significantly restricted availability of R417A er than for R417A. This results in different and R438A. performance parameters and a different focus within the application range. BITZER compressors are suitable for use The same applies to a further blend with the with R417A/417B/422D/438A. An individ - same main components, but R600a as ual selection is possible upon request.

22 Substitutes for R22 in A/C and heat pumps

R427A meets the requirement of the EU R32 as substitute for R22 It was proven in flammability tests that the F-Gas Regulation, which will only allow necessary ignition energy is very high and refrigerants with GWP < 2500 from 2020. the flame speed is low. Therefore, R32 As described earlier, R32 belongs to the However, the quantity limitation due to the (like R1234yf and R1234ze) has been HFC refrigerants, but initially it was mainly "phase-down" will also lead to significantly placed in the new safety group A2L ac- used as a component of refrigerant blends restricted availability. cording to ISO 817. only. An essential barrier for the application BITZER compressors are suitable for as a pure substance so far is the flammabil- The resulting safety requirements are spe - R427A. An individual selection is pos - ity. This requires adequate charge limita - cified in the revised EN 378 (amended ver - sible upon demand. tions and/or additional safety measures, sion 2016). especially with installations inside buildings. R32 is also considered an alternative for In addition there are very high pressure Supplementary information concerning systems with larger refrigerant charge, e.g. levels and discharge gas temperatures the use of HFC blends liquid chillers for air conditioning and pro - (compression exponent higher than with (see also https://www.bitzer.de) cess applications and heat pumps pre - R22 and R410A). o Technical information A-540 viously operated with R410A. However, “Retrofit R22 or R404A/R507A – Step On the other hand, R32 has favorable ther - depending on the installation site of the by step” modynamic properties, e.g. very high evap- system, appropriate refrigerant charge orating enthalpy and volumetric refriger- limits must be observed. On the other ating capacity, low vapor density (low hand, there are no such restrictions when pressure drop in pipelines), low mass flow, installed outdoors (without access to un- and favorable power input for compression. authorized persons) and in machine rooms The global warming potential is relatively (for example, according to EN 378-3: low (GWP = 675). 2016). It should be noted, however, that R32 precharged chillers may be subject to Looking at these favorable properties and special conditions during transport (accord- taking into account the additional effort for ing to the Pressure Equipment Directive, emission reductions, R32 will increasingly R32 is classified under Fluid Group 1). be used as a refrigerant in factory produced systems (A/C units, liquid chillers, heat BITZER scroll compressors of the ORBIT pumps). GSD6..AL and GSD8..AL series have been approved and released for use with R32.

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"Low GWP" HFOs and HFO/HFC R1234ze(E) is sometimes referred to as a R410A in blends of GWP < approx. 2000. blends as alternatives to HFCs R134a substitute, but its volumetric refriger- The reason for this is the high GWP of ating capacity is more than 20% lower each of the required non-flammable com - than that of R134a or R1234yf. The boiling ponents. There are a few exceptions, which The decision to use the "low GWP" refriger - point (-19°C) also greatly restricts the appli - are discussed in chapter Further develop- ant R1234yf in mobile air conditioning sys - cation at lower evaporation temperatures. ment projects with “Low GWP” refrigerants, tems for passenger cars (see pages 11/12) Its preferred use is therefore in liquid page 26. also led to the development of alternatives chillers and high temperature applications. For R134a alternatives, the situation is for further mobile applications as well as For further information see chapter Refriger- more favorable. Due to the already quite stationary refrigeration, air conditioning and ants for special applications, page 37. low GWP of R134a, a blend with R1234yf heat pump systems. and/or R1234ze(E) allows a formulation of The list of further potential HFO refriger - non-flammable refrigerants with a GWP of Primary objectives are the use of single- ants is relatively long. However, there are approx. 600. component refrigerants and of mixtures only few fluids that meet the requirements with significantly reduced GWP and similar in terms of thermodynamic properties, Thus, primarily two directions for develop - thermodynamic properties as the HFCs flammability, toxicity, chemical stability, ment are pursued: currently used predominantly. compatibility with materials and lubri cants. o Non-flammable HFC alternatives These include e.g. the non-flammable (safe - (blends) with GWP values according to An essential basic component for this is ty group A1) low-pressure refrigerants the above mentioned limits – safety R1234yf (CF CF=CH ). This refrigerant 3 2 R1224yd(Z), R1233zd(E), R1336mzz(E), group A1. Regarding safety require - belongs to the group of hydro-fluoro-olefins R1336mzz(Z) and R514A (blend of ments, these refrigerants can then be (HFO), i.e. unsaturated HFCs with molecu - R1336mzz(Z)/R1130(E)). These are primari - utilized similar to currently used HFCs. lar double bonds. This group of HFOs also ly an option for liquid chillers with large o Flammable HFC alternatives (blends) includes another substance called turbo-compressors, and they can be used with GWP values below the above men - R1234ze(E), which has been mainly used with positive displacement compressors in tioned possible limits – according to as a propellant for PU foam and aerosol. high-temperature applications as well as safety group A2L (for refrigerants of R1234ze(E) (CF CH=CFH) differs from 3 ORC systems. Further information: see lower flammability). R1234yf in its molecular structure. chapter Refrigerants for special applica- This group of refrigerants is then subject to Both substances are the preferred choice tions, page 37. charge limitations according to future re- in terms of their properties and are also R1224yd(Z) and R1233zd(E) belong to the quirements for A2L refrigerants. used as basic components in HFO/HFC group of HCFO (hydro-chloro-fluoro-olefins); blends. The Global Warming Potential is Meanwhile, there are development projects they have a (very) low ozone depletion very low − R1234yf with GWP 4 and using refrigerant components with a much potential (ODP). Upon release into the R1234ze(E) with GWP 7. However, these higher volumetric refrigerating capacity and atmosphere, however, the molecule rapidly refrigerants are flammable (safety class pressure than R1234yf and R1234ze(E). disintegrates. A2L), meaning the refrigerant quantity in These can then be used to "formulate" mix - the system must be considered in light of On the other hand, there are currently no tures with R32 as an alternative to R410A, the installation location. In addition, there candidates from the HFO family with similar which are optimised for certain properties. remain open questions concerning the volumetric refrigerating capacity such as See additional information in chapter Fur - long-term stability in stationary systems R22/R407C, R404A/R507A and R410A ther development projects with “Low GWP” where long life cycles are common. Fur - available for commercial use. Direct alter - refrigerants, page 26. thermore the volumetric refrigerating natives for these refrigerants with signifi - capacity is relatively low; for R1234yf it is cantly lower GWPs must therefore be “con - R134a alternatives close to the level of R134a, and more than structed” as a mixture of R1234yf and/or 20% lower for R1234ze(E). R1234ze(E) with HFC refrigerants, possibly In addition to the flammable HFO refriger - also small proportions of hydrocarbons, ants R1234yf and R1234ze(E) already There is also some uncertainty concerning CO or other suitable molecules. described, non-flammable mixtures are flammability. In safety data sheets, 2 now also available as R134a alternatives. R1234ze(E) is declared as non-flammable. However, due to the properties of the HFC As previously mentioned, the initial situa - However, this only applies to its transport refrigerants suitable as blend components, tion is most favorable for these. and storage. When used as a refrigerant, a flammability and GWP are related diametri - higher reference temperature for flammabil - cally to one another. In other words: Blends They achieve GWP values of approx. 600 − ity tests of 60°C applies. At this tempera - as alternatives to R22/R407C of GWP less than half of R134a (GWP = 1430). In ture, R1234ze(E) is flammable and there - < approx. 900 are flammable. This is also addition, this type of blends can have fore classified in safety class A2L, like true with alternatives for R404A/R507A in azeotropic properties, so that they can be R1234yf. blends of GWP < approx. 1300 and for used like pure refrigerants.

24 HFOs and HFO/HFC blends

For quite some time a blend has been ture heat pumps. Due to the two main HFO frige rating capacity, this requires a very applied on a larger scale in real systems – components, the GWP of the blend is high proportion of R32, which is why only this was developed by Chemours and is < 150, but it is still non-flammable (A1). GWP values from approx. 400 to 500 can TM XP-10. Results available called Opteon A disadvantage, however, is the even lower be achieved. With a higher HFO proportion, today are highly satisfactory. volumetric refrigerating capacity compared the GWP can be reduced even further, but at the cost of a clearly reduced refrigerating This is also true for an R134a alternative to R515B. capacity. designated Solstice ® N-13 and offered by Honeywell which, however, differs regard - Substitutes for R404A/R507A and All blend options described above with ing the blend composition. R410A R1234yf and R1234ze(E) show a more or less distinct temperature glide due to boil- The refrigerants are listed in the ASHRAE Since the available HFO molecules ing point differences of the individual com - nomenclature under R513A (Chemours) (R1234yf and R1234ze) show a consider - ponents. The same criteria apply as de- and R450A (Honeywell). ably smaller volumetric refrigerating capaci - scribed in context with R407C. The same category also includes the re- ty than the above mentioned HFC refriger- ants, relatively large HFC proportions with Beyond that, the discharge gas temperature frigerant blends R516A (ARKEMA ARM 42) of most R404A/R507A alternatives is consi - as well as R456A (Koura/Mexichem AC5X). high volumetric refrigerating capacity must be added for the particular alternatives. derably higher than for these HFC blends. All options show refrigerating capacity, The potential list of candidates is rather In single stage low temperature systems power input, and pressure levels similar to limited, one option is R32 with its relatively this may lead to restrictions in the com - R134a. Thus, components and system low GWP of 675. pressor application range or require special technology can be taken over, only minor measures for additional cooling. In trans - However, one disadvantage is its flamma- changes like superheat adjustment of the port applications or in low temperature bility (A2L), resulting also in a flammable expansion valves are necessary. systems with smaller condensing units, the blend upon adding fairly large proportions compressors used can often not meet the Polyolester oils are suitable lubricants in order to increase the volumetric refriger- required operating ranges, due to the high which must meet special requirements, e.g. ating capacity while maintaining a favor- discharge gas temperatures. This is why for the utilization of additives. able GWP. refrigerant blends based on R32 and HFO Prospects are especially favorable for For a non-flammable blend, on the other with a higher proportion of R125 have also supermarket applications in the medium hand, a fairly large proportion of refriger- been developed. The GWP is slightly temperature range in a cascade with CO 2 ants with high fluor content (e.g. R125) above 2000, but below the limit of 2500 set for low temperature, just as in liquid chillers must be added. A drawback here is the in the EU F-Gas Regulation from 2020. The with higher refrigerant charges where the high GWP of more than approx. 900 for main advantage of such blends is their use of flammable or toxic refrigerants would non-flammable R22/R407C alternatives moderate discharge gas temperature, require comprehensive safety measures. and more than approx. 1300 with options which allows the operation within the typi - for R404A/ R507A. Compared to R404A/ cal application limits of R404A. A special case is the refrigerant R515B: an R507A, however, this means a reduction The following table (Tab. 4) shows the azeotropic mixture of R1234ze(E) and down to a third. small amounts of R227ea. This combina - potential blend components for the alter- tion, declared by the manufacturer Honey- The future drastic "phase-down " of F-Gases, natives described above. With some re- well as an R134a alternative, is non- e.g. as part of the EU F-Gas Regulation, frigerants the mixture components for flammable (A1) despite the very low GWP already leads to a demand for R404A/ R22/R407C and R404A/R507A substitutes of approx. 300. R507A substitutes with GWP values clearly are identical, but their distribution in per - below 500. Although this is possible with cent is different. However, as with the previously described an adequate composition of the blend (high In the meantime, Chemours, Honeywell, R1234ze(E), this can only be considered proportions of HFO, R152a, possibly also Arkema, Mexichem and Daikin Chemical an alternative under certain restrictions. hydrocarbons), the disadvantage will be its have offered corresponding chemical vari - The volumetric refrigerating capacity is also flammability (safety groups A2L or A2). In ants for laboratory and field tests, and in more than 20% lower than that of R134a or this case, the application will have higher some cases already for commercial use. A R1234yf. safety requirements and will need an ad- number of refrigerants are still declared as equately adjusted system technology. This category of substitutes also includes being under development and are only R471A (Honeywell), a blend of R1234ze(E), R410A currently has no non-flammable made available for testing purposes under R1336mzz(E) and R227ea. R1336mzz(E) alternatives for a broader use in commercial special agreements. Until now, trade is a non-flammable HFO low-pressure applications. Either R32 (see page 23) as names are often used although a larger refrigerant which can also be used with pure substance or blends of R32 and HFO number of HFO/HFC blends are already turbo compressors and for high tempera - can be used. Due to its high volumetric re- listed in the ASHRAE nomenclature.

25 HFOs and HFO/HFC blends

The following table (Tab. 5) lists a range of R466A is a mixture of R32, R125 and A final assessment of these mixtures is currently available refrigerants or refriger- R13I1 (CF 3I − trifluoroiodomethane), an therefore currently not possible. ants declared as development products. iodine-methane derivative not previously Due to the large number of different ver - used in refrigeration. CF 3I is not flam- Comment from a compressor manufactur - sions and the potential changes in develop - mable, as is R125, which means that the er’s point of view: ment products, the tables on pages 42/43 refrigerant is not flammable (A1), even with It should be an aim to limit the product (Tab. 7/8) only list data of alternatives for the relatively high proportion of R32 (A2L). variety currently becoming apparent and to R134a, R404A/R507A and R410A which reduce the future supply to a few "stan - Despite the noticeable proportion of R125 are already commercially available. dard refrigerants". It will not be possible for with a GWP of 3500, the total GWP is 733 component and equipment manufacturers For testing the "Low GWP" refrigerants, (AR4) and therefore in the range of R32 nor for installers and service companies to AHRI (USA) has initiated the "Alternative and R452B, which are however classified deal in practice with a larger range of Refrigerants Evaluation Program (AREP)". as A2L. alternatives. It has investigated and evaluated several of From a thermodynamic point of view, the the products mentioned in Tab. 5 as well differences between R410A and R466A are BITZER was involved early on in various as halogen-free refrigerants. relatively small. Volumetric refrigerating projects with HFO/HFC blends and was capacity, pressure levels and discharge thus able to gain important insight into Further development projects with temperature are slightly higher, the refriger- the use of these refrigerants. Semi-her - "Low GWP" refrigerants ant mass flow deviates slightly more metic reciprocating compressors of the For specific applications, Chemours has (about 15 to 20% higher). The temperature ECOLINE series as well as CS. and HS. developed a non-flammable (A1) R410A glide is also very low. screw compressors can already be used alternative, which is marketed in selected with this new generation of refrigerants. Hence, R466A appears to be a promising countries and regions under the trade substitute for R410A. However, due to the Several of them have already been name Opteon TM XP41 – listed by ASHRAE CF I share, there are still uncertainties qualified and approved, the respective as R463A. 3 regarding long-term chemical stability and performance data is available on the It is a mixture of R32, R125, R1234yf, material compatibility under the special BITZER SOFTWARE. R134a and CO with a GWP of 1494. requirements of the refrigeration cycle. 2 Scroll compressors of the ORBIT Despite the high proportion of R32 and Further investigation is required, so a final GSD6..VL and GSD8..VL series are R1234yf, flammability is suppressed by assessment of R466A is currently not pos - approved and released for the use of the mixing with R125, R134a and CO . 2 sible. In any case, as matters stand, this R32/HFO mixtures R452B and R454B. Regarding thermodynamics, the differences refrigerant cannot be used in state-of-the- to R410A are comparatively small. The art systems (retrofit). The supply of com - Further information on the application addition of CO 2, however, leads to a pressors for laboratory tests requires an of HFOs and HFO/HFC blends see bro - distinct temperature glide, which may individual review of the specific application chure A-510, section 6. cause certain limitations for the application as well as a special agreement. and places particular demand on the AGC Chemicals propagates R1123 design of the heat exchangers. (CF 2=CHF) mixed with R32, partially with All mixture components and their properties addition of R134yf, as an alternative to are well known, which means there are no R410A and pure R32. It is an HCFO with additional particularities regarding material very low ozone depletion potential (ODP). compatibility in comparison to the already R1123 has a significantly higher volumetric known R410A alternatives. refrigeration capacity than R1234yf or R1234ze(E) and is advantageous in this The supply of compressors for laboratory respect. However, the pressure level is or field tests requires an individual review even higher than of R32 and the critical of the specific application and a special temperature is only about 59°C. Apart from agreement. that, there are unanswered questions about Some time ago, Honeywell has unveiled the chemical long-term stability under the the new development of a non-flammable special requirements of the refrigeration (A1) R410A alternative under the trade cycle. According to the safety data sheet, name Solstice ® N-41 – listed by ASHRAE this substance is also subject to very strin - as R466A. gent safety requirements.

26 HFOs and HFO/HFC blends

09.20 Actual Alternatives Components / Mixture components "Low GWP" alternatives (Examples) HFC Refrigerants Safety GWP ④ R1234yf R1234ze(E) R32 R152a R134a R125 R13I1 ⑤ R227ea R1336mzz(E ) CO 2② R290 ② Group A2L A2L A2L A2 A1 A1 A1 A1 A1 A1 A3

GWP 4 7 675 124 1430 3500 <1 3220 7 1 3 A1 ~ 600     A1 ~ 300 ⑥   R134a A1 < 150 ⑥    GWP 1430 A2L < 150      A2L < 10   A1 < 2500 ①    A1 ~ 1400      R404A/R507A A2L < 250    GWP 3922/3985 A2L ③ < 150    A2 < 150    A1 900..1400      R22/R407C A2L < 250    GWP 1810/1774 A2L < 150   A2 < 150    A1 < 1500      R410A A1 < 750    GWP 2088 A2L < 750  A2L ~ 400..750    

① Refrigerating capacity, mass flow, discharge gas temperature similar to R404A ④ Approx. values according to IPCC IV (AR4) ② Only low percentage – due to temperature glide (CO 2) and flammability (R290 ⑤ R13I1 (CF 3I − tri-fluoroiodomethane) is an iodine-methane derivative ② R32/HFO blends show lower refrigerating capacity than reference refrigerant, ⑥ Lower volumetric refrigerating capacity than reference refrigerant the addtion of CO 2 leads to high temperature glide Tab. 4 Potential mixture components for "Low GWP" alternatives (examples) 09.20

Current Low GWP" Alternatives for HFC refrigerant HFC Refrigerants "

ASHRAE Trade Composition GWP ③ Safety Boiling tempe- Temperature Number Name (with blends) AR4 (AR5) group rature [°C] ④ glide [K] ⑤ R450A Solstice ® N-13 Honeywell R1234ze(E)/134a 604 (547) A1 -24 0.6 R456A AC5X ⑥ Koura (Mexichem) R32/1234ze(E)/134a 687 (627) A1 -30 4.8 Opteon TM XP10 Chemours R513A R1234yf/134a 631 (573) A1 -30 0 R513A Daikin Chemical R 1 3 4 a R515B ② – Honeywell R1234ze(E)/227ea 293 (299) A1 -19 0 G W P 1 4 3 0 ① R471A ② – Honeywell R1234ze(E)/1336mzz(E)/227ea 148 (148) A1 -17 3.2 R1234yf various _ 4 (< 1) A2L -30 0 R1234ze(E) ② various _ 7 (< 1) A2L -19 0 R444A AC5 ⑥ Koura (Mexichem) R32/152a/1234ze(E) 92 (89) A2L -34 10 R516A ARM-42 Arkema R1234yf/R152a/R134a 142 (131) A2L -29 0 R448A Solstice ® N-40 Honeywell R32/125/1234yf/1234ze(E)/134a 1387 (1273) A1 -46 6.2 Opteon TM XP40 Chemours R449A R32/125/1234yf/134a 1397 (1282) A1 -46 5.7 Forane ® 449 Arkema R452A Opteon TM XP44 Chemours R32/125/1234yf 2140 (1945) A1 -47 3.8 R 4 0 4 A / R 5 0 7 A Opteon TM XL40 Chemours R454A R32/1234yf 239 (238) A2L -48 5.7 G W P 3 9 2 2 / 3 9 8 5 R454A Daikin Chemical R457B ARM-20b Arkema R32/1234yf/152a 251 (251) A2L -47 6.1 ( R 2 2 / R 4 0 7 ) R454C ② Opteon TM XL20 Chemours R32/1234yf 148 (146) A2L -46 7.8 ® R455A Solstice L-40X Honeywell R32/1234yf/CO 2 148 (146) A2L -52 12.8 R457A ② ARM-20a Arkema R32/1234yf/152a 139 (139) A2L -43 7.2 R465A ARM-25 Arkema R32/1234yf/290 145 (143) A2 -52 11.8 R468A Daikin Chemical R32/1234yf/1132a 148 (147) A2L -51 12.3 R 2 2 / R 4 0 7 C R449C Opteon TM XP20 Chemours R32/125/1234yf/134a 1251 (1146) A1 -44 6.1 GWP 1810/1774 R32 various – 675 (677) A2L -52 0 Opteon TM XL55 Chemours R452B R32/125/1234yf 698 (676) A2L -51 0.9 R 4 1 0 A Solstice ® L-41y Honeywell G W P 2 0 8 8 R454B Opteon TM XL41 Chemours R32/1234yf 466 (467) A2L -51 1.0 TM R463A Opteon XP41 Chemours R32/125/1234yf/134a/CO 2 1494 (1377) A1 -59 12.2 ® R466A Solstice N-41 Honeywell R32/125/13I1(CF 3I) 733 (696) A1 -52 0.7 ① The relatively low GWP allows the use of R134a also on longer term. ④ Rounded values ② Lower volumetric refrigerating capacity than reference refrigerant ⑤ Total glide from bubble to dew line at 1.013 bar (abs.) ③ AR4: according to IPCC IV // AR5: according to IPCC V – time horizon 100 years ⑥ Development product Tab. 5 Low GWP " alternatives for HFC refrigerants – for further data see Tab. 7 and 8 ( Refrigerant Properties ") " " 27 Halogen free (natural) refrigerants

NH 3 (Ammonia) as able for large plants, makes the control of These measures significantly increase the alternative refrigerant the refrigerant injection more difficult with expenditure for NH 3 plants, especially for small capacities. medium and smaller capacities. Further to be considered is the corrosive Efforts are therefore being made world-wide The refrigerant NH 3 has been used for more than a century in industrial and larger refriger- action on copper containing materials; pipe to develop simpler systems which can also ation plants. It has no ozone depletion po- lines must therefore be made of steel. This be used in the commercial area. also hinders the development of motor wind- tential and no direct global warming poten- A part of the research programs is dealing ings resistant to NH as basis for semi-her - tial. The efficiency is at least as good as that 3 with part soluble lubricants, with the aim of metic constructions. Another difficulty arises of R22, in some areas even more favour- improving oil circulation in the system. Sim - from the electrical conductivity of the re- able; the contribution to the indirect global plified methods for automatic return of non- frigerant in case of higher moisture content. warming effect is therefore small. In addition, soluble oils are also being examined as an its price is exceptionally low. Is it therefore Additional characteristics include toxicity and alternative. an ideal refrigerant and an optimum substi - flammability, which require special safety tute for R22 or an alternative for HFCs!? measures for the construction and operation BITZER is strongly involved in these NH 3 has indeed very positive features, of such systems. projects and has a large number of which can be exploited quite well in large operating compressors. The experi- refrigeration systems and heat pumps. ences up to now have revealed that Resulting design and construction criteria Unfortunately there are also negative as- systems with partly soluble oils are dif - pects, which restrict the wider use in the com- Based on the present "state of technology", ficult to manage. The moisture content mercial area or require costly and some- industrial NH 3 systems demand a complete - in the system has an important influ- times new technical developments. ly different plant technology, compared to ence on the chemical stability of the usual commercial systems. circuit and the wear of the compressor. A disadvantage with NH 3 is the high isen- Besides, high refrigerant solution in the tropic exponent (NH 3 = 1.31 / R22 = 1.19 / Due to the insolubility with the lubricating oil oil (wet operation, insufficient oil tem - R134a = 1.1), which results in a discharge and the specific characteristics of the re- perature) leads to strong wear on the temperature even significantly higher than frigerant, high efficiency oil separators and bearings and other moving parts. This that of R22. Single stage compression is flooded evaporators with gravity or pump is due to the enormous volume change therefore already subject to certain restric - circulation are usually employed. Because when NH 3 evaporates in the lubricated tions below an evaporating temperature of of the danger to the public and to the pro - areas. around -10°C. duct to be cooled, the evaporator often can - These research developments are not be installed directly at the cold space The question of suitable lubricants is also being continued, with focus also on and the heat must be transported by a sec- not satisfactorily solved for smaller plants in alternative solutions for non-soluble ondary refrigerant circuit. some kinds of applications. The most com - lubricants. monly used mineral oils and polyalpha-ole - Due to the thermal behaviour, two stage fins are not soluble with the refrigerant. They compressors or screw compressors with Various equipment manufacturers have must be separated with complex technology generously sized oil coolers must be used developed special evaporators, allowing and seriously limit the use of "direct expan - even at medium pressure ratios. significantly reduced refrigerant charge. sion evaporators" due to the deterioration in There is a strong trend towards so-called Refrigerant lines, heat exchangers and fit - the heat transfer. "low charge" systems, i.a. with regard to tings must be made of steel; larger size safety requirements, which are also largely Special demands are made on the thermal pipe lines must be examined by a certified determined by the refrigerant charge. stability of the lubricants due to the high inspector. In some cases, aluminium can discharge gas temperatures. This is especi - also be used as a material. In addition to this, there are developments ally valid when automatic operation is con- for the "sealing" of NH plants: compact Depending upon the size of the plant and 3 sidered where the oil is supposed to remain liquid chillers (charge below 50 kg), in- the refrigerant charge, corresponding safety in the circuit for years without losing any of stalled in a closed container and partly with measures and special machine rooms are its stability. an integrated water reservoir to absorb NH required. 3 NH 3 has an extraordinarily high enthalpy dif - in case of a leak. This type of compact unit ference and thus a very small circulating The refrigeration compressor is usually of can be installed in areas which were pre - mass flow (approximately 13 to 15% com- "open" design, the drive motor is a separate viously reserved for plants with refrigerants pared to R22). This feature, which is favour- component. of safety group A1 due to safety requirements.

28 Halogen free (natural) refrigerants

An assessment of NH 3 compact systems – Conversion of existing plants R723 (NH₃/DME) as instead of systems using HFC refrigerants The refrigerant NH 3 is not suitable for the an alternative to NH 3 and conventional technology – is only pos- conversion of existing (H)CFC or HFC sible on an individual basis, taking into plants; they must be constructed completely The previously described experiences with account the particular application. From a new with all components. merely technical viewpoint and presuppos- the use of NH 3 in commercial refrigeration plants with direct evaporation caused fur- ing an acceptable price level, a wider range Supplementary BITZER information ther experiments on the basis of NH 3 by of products will supposedly become avail- concerning the application of NH able in the foreseeable future. 3 adding an oil soluble refrigerant component. (see also https://www.bitzer.de) Main goals were improved oil transport and o Technical Information AT-640 heat transmission with conventional lubri - The product range from BITZER today “Use of Ammonia (R717) in BITZER cants, along with a reduced discharge gas includes an extensive selection of opti - compressors” temperature for the extended application mized NH 3 compressors for various range with single stage compressors. types of lubricants: The result of this research project is a re- o Single stage open reciprocating frigerant blend of NH (60%) and dimethyl compressors (displacement 19 to 3 ether "DME" (40%), It was developed by the 152 m 3/h with 1450 rpm) for air con - Institute of Air Handling and Refrigeration ditioning, medium temperature and (ILK) in Dresden, Germany, and has been booster applications applied in a series of real systems. As a o Open screw compressors (displace - largely inorganic refrigerant it received the ment 84 to 1015 m 3/h – with parallel designation R723 due to it its average mo- operation to 4060 m 3/h – with 2900 lecular weight of 23 kg/kmol in accordance rpm) for air conditioning, medium to the standard refrigerant nomenclature. and low temperature cooling. Options for low temperature cooling: – Single stage operation – Economiser operation – Booster operation

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29 Halogen free (natural) refrigerants

DME was selected as an additional compo - fore, the proportion of DME leads to im- R290 (Propane) as nent for its good solubility and high individ- proved oil solubility and a partial miscibility. alternative refrigerant ual stability. Its boiling point is -26°C, the Furthermore, the relatively low liquid density adiabatic exponent is relatively low, it is not and an increased DME concentration in the R290 (propane) can also be used as a sub - toxic and available in high purity. In the oil enhances oil circulation. PAG oils would stitute refrigerant. Being an organic com - abovementioned concentration NH and be fully or partly miscible with R723 for typi - 3 pound (hydrocarbon), it has no ozone DME form an azeotropic blend character- cal applications, but are not recommended depletion potential and a negligible direct ised by a slightly higher pressure level than because of the chemical stability and high global warming effect. To take into consid- pure NH . The boiling point lies at -36.5°C solubility in the compressor crankcase 3 eration however, is a certain contribution to (NH -33.4°C), 26 bar (abs.) of condensing (strong vapour development in the bear- 3 summer smog. pressure corresponds to 58.2°C (NH 3 ings). 59.7°C). Pressure levels and refrigerating capacity Tests have shown that the heat transfer are similar to R22, and its temperature The discharge gas temperature in air condi - coefficient at evaporation and high heat flux behaviour is as favourable as with R134a. tioning and medium temperature ranges is improved in systems with R723 and min- decreases by about 10 to 25 K (Fig. 24) eral oil compared to NH 3 with mineral oil. There are no particular problems with mate - and allows an extended application range to rial. In contrast to NH , copper materials Further characteristics are toxicity and flam - 3 higher pressure ratios. Thermodynamic are also suitable, so that semi-hermetic and mability. The DME content lowers the igni - calculations conclude a single-digit percent hermetic compressors are possible. Com - tion point in air from 15 to 6%. However, the rise in refrigerating capacity com pared to mon mineral oils of HCFC systems can be azeotrope is ranked in safety group B2, but NH . The coefficient of performance is simi - used here as a lubricant over a wide appli - 3 may receive a different classification in case lar and is even more favourable at high cation range. Polyol esters (POE) and poly - of a revised assessment. pressure ratios, confirmed by experiments. alpha-olefins (PAO) offer even more favor- Due to the lower temperature level during able properties. compression, an improved volumetric and Resulting layout criteria Refrigeration plants with R290 have been in isentropic efficiency can be expected, at Experiences with the NH compact systems operation world-wide for many years, mainly least with reciprocating compressors in 3 described above can be used in plant tech - in the industrial area – it is a "proven" refriger- case of an increasing pressure ratio. nology. However, the component layout has ant. Due to the higher molecular weight of DME, to be adjusted considering the higher mass Meanwhile R290 is also used in smaller com- mass flow and vapour density increase by flow. By appropriate selection of the evapo - pact systems with low refrigerant charges nearly 50% compared to NH 3, although this rator and the expansion valve, a very stable like residential air-conditioning units and is of little importance to commercial plants, superheat control must be ensured. Due to heat pumps. Furthermore, a rising trend can especially in short circuits. In conventional be observed in its use with commercial re- the improved oil solubility, "wet operation” industrial refrigeration plants, however, this can have considerable negative results frigeration systems and chillers. is a substantial criterion with regard to pres - compared to NH systems with non-soluble 3 Propane is offered also as a mixture with sure drops and refrigerant circulation. oil. Isobutane (R600a) or Ethan (R170), in These considerations again show that the With regard to safety regulations, the same order to provide a similar performance to preferred application area of R723 is in criteria apply to installation and operation as halocarbon refrigerants. Pure Isobutane is commercial applications and especially in for NH plants. mostly intended as a substitute for R12 in liquid chillers. 3 small systems (preferably domestic refriger- Suitable compressors are special NH ver - Material compatibility is comparable to that 3 ators and freezers). sions which possibly have to be adapted to of NH . Although non-ferrous metals (e.g. 3 the mass flow and the continuous oil circu - The disadvantage of hydrocarbons is their CuNi alloys, bronze, hard solders) are lation. An oil separator is usually not neces - high flammability, therefore they are classi - potentially suitable, provided minimum sary with reciprocating compressors. fied as refrigerants of "Safety Group A3". water content in the system (< 1000 ppm), Based on the refrigerant charge quantities a system design similar to typical ammonia BITZER N H reciprocating compressors commonly used in commercial systems, the practise is recommended. 3 are suitable for R723 in principle. An system design and risk analysis must be in Mineral oils or (preferred) polyalpha olefin individual selection of specifically adapt- accordance with explosion protection regu - are suitable lubricants. As mentioned be- ed compressors is possible on demand. lations.

30 Halogen free (natural) refrigerants

Semi-hermetic compressors in so-called should be considered (approximately 55 to a specifically equipped compressor ver - "hermetically sealed" systems are in this 60% compared to R22). An advantage here sion is offered. Inquiries and orders case subject to regulations for hazardous is that the refrigerant charge can be greatly need a clear reference to R290. The zone 2 (only seldom and short term risk). reduced. From the thermodynamic point of handling of the order includes an individua l Safety demands include special devices to view, an internal heat exchanger between agreement between the contract part - protect against excess pressures and speci - the suction and liquid line is recommended ners. Open reciprocating compressors al arrangements for the electrical system. In as this will improve the refrigerating capaci - are also available for R290, together with addition, measures are required to ensure ty and COP. a comprehensive program of flame-proof hazard free ventilation to effectively prevent accessories which may be required. Owing to the particularly high solubility of a flammable gas mixture in case of refriger- R290 (and R1270) in common lubricants, ant leakage. Conversion of existing plants with R22 BITZER R290/R1270 compressors are or HFC to R290 Design requirements are defined by stan - charged with special oil of a high viscosity dards (e.g. EN378) and may vary in differ- index and particularly good tribological Due to the special safety measures when ent countries. For systems applied in the properties. using R290, a conversion of existing sys - EU, an assessment according to EC Direc- Again, an internal heat exchanger is of tems only seems possible in exceptional tive 94/9/EC (ATEX) may become necessary advantage as it leads to higher oil tempera - cases. They are limited to systems, which as well. With open compressors, this will tures, lower solubility and therefore im- can be modified to meet the corresponding possibly lead to a classification in zone 1 ‒ proved viscosity. safety regulations with an acceptable effort. which demands, however, electrical equip - Due to the very favourable temperature ment in special flame-proof design. Supplementary BITZER information behaviour (Fig. 24), single stage compres - concerning the use of R290 sors can be used down to approximately Resulting design criteria (see also https://www.bitzer.de) - 40°C evaporation temperature. R290 could Apart from the measures mentioned above, thus also be considered as an alternative o Technical Information AT-660 propane systems require practically no spe - for some of the HFC blends. “Use of propane (R290) and cial features in the medium and low tempera - propene (R1270) in semi-hermetic ture ranges compared to a usual (H)CFC A range of ECOLINE compressors and BITZER compressors” and HFC system. When sizing components, CS. compact screws is available for however, the relatively low mass flow R290. Due to the individual requirements

 

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Propylene (R1270) as an ever, tests by hydrocarbon manufacturers charge gas temperature of R1270, restrictions alternative to Propane and stability tests in real applications show are partly necessary at high pressure ratios. practically no reactivity in refrigeration sys - tems. Doubts have occasionally been A range of ECOLINE compressors and CS. For some time there has been increasing voiced in some literature regarding possible compact screws is available for R1270. interest in using propylene (propene) as a carcinogenic effects of propylene. These Due to the individual requirements a substitute for R22 or HFC. Due to its higher assumptions have been disproved by ap- specifically equipped compressor version volumetric refrigerating capacity and lower propriate studies. is offered. Inquiries and orders need a boiling temperature (compared to R290), clear reference to R1270. applications in medium and low temperature Resulting design criteria systems are of particular interest, e.g. liquid The handling of the order includes an indi - chillers for supermarkets. On the other With regard to system technology, experi - vidual agreement between the contract hand, higher pressure levels (> 20%) and ence gained from the use of propane can partners. Open reciprocating compressors discharge gas temperatures have to be widely be applied to propylene. However, are also available for R1270, together with taken into consideration, thus restricting the component dimensions have to be altered a comprehensive program of flame-proof possible application range. due to higher volumetric refrigerating capac - accessories which may be required. ity (Fig. 26). The compressor displacement Material compatibility is comparable to is correspondingly lower, as are the suction Supplementary BITZER information propane, as is the choice of lubricants. and high pressure volume flows. Because concerning the use of R1270 Propylene is also easily inflammable and of higher vapour density, the mass flow is (see also https://www.bitzer.de) belongs to the safety group A3. The same almost the same as for R290. As liquid den - o Technical Information AT-660 safety regulations are therefore to be sity is nearly identical, the same applies to “Use of propane (R290) and observed as with propane (page 31). the liquid volume in circulation. propene (R1270) in semi-hermetic Due to the chemical double bond, propylene As with R290, an internal heat exchanger BITZER compressors” reacts quite easily, risking polymerization at between suction and liquid lines is of high pressure and temperature levels. How - advantage. However, due to the higher dis -

32 Halogen free (natural) refrigerants

Carbon dioxide R744 (CO 2) were e.g. marine refrigeration systems. With long periods. It should further be noted that as an alternative refrigerant the introduction of the "(H)CFC Safety Re- the heat transfer coefficients of CO 2 are frigerants", CO 2 became less popular and considerably higher than of other refrige - and secondary fluid had nearly disappeared by the 1950’s. rants – with the potential of very low tempe - rature differences in evaporators, conden - The main reasons for that are its relatively CO 2 has had a long tradition in the refriger- sers, and gas coolers. Moreover, the ation technology reaching far into the 19th unfavourable thermodynamic characteristics necessary pipe dimensions are very small, century. It has no ozone depleting potential, for usual applications in refrigeration and air and the influence of the pressure drop is a negligible direct global warming potential conditioning. comparably low. In addition, when used as (GWP = 1), is chemically inactive, non-flam - a secondary fluid, the energy demand for The discharge pressure with CO 2 is ex- mable and not toxic in the classical sense. tremely high, and the critical temperature at circulation pumps is extremely low. Therefore, CO is not subjected to the strin - 2 31°C (74 bar) very low. Depending on the In the following section, a few examples of gent containment demands of HFCs (F-Gas heat sink temperature at the high pressure subcritical systems and resulting design cri - Regulation) and flammable or toxic re- side, transcritical operations with pressures teria are described. An additional section frigerants. However, compared to HFCs the beyond 100 bar are required. Under these provides details on transcritical applica- lower critical value in air has to be consid- conditions, energy efficiency is often lower tions. ered. For closed rooms, this may require than in the classic vapour compression pro - special safety and detection systems. cess (with condensation), therefore the indi - rect global warming effect is higher. CO 2 is also low in cost and there is no Subcritical CO 2 applications necessity for recovery and disposal. In addi - Nonetheless, there is a range of applica - From energy and pressure level points of tion, it has a very high volumetric refrigerat- tions in which CO can be used very eco- view, very beneficial applications can be ing capacity: depending on operating condi - 2 nomically and with favourable eco-efficiency. seen for industrial and larger commercial tions, approx. 5 to 8 times as high as R22 These include subcritical cascade plants, refrigeration plants. For this, CO can be and NH . 2 3 but also transcritical systems, in which the used as a secondary fluid in a cascade sys - Above all, the safety relevant characteristics temperature glide on the high pressure side tem and if required, in combination with a were an essential reason for the initial wide - can be used advantageously, or the system further booster stage for lower evaporating spread use. The main focus for applications conditions permit subcritical operation for temperatures (Fig. 30).

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Fig. 28 R744(CO 2) – pressure/enthalpy diagram Fig. 29 R744(CO 2)/R22/R404A – comparison of pressure levels

33 Halogen free (natural) refrigerants

The operating conditions are always subcrit - often used with NH 3 plants. The essential orators is then limited with view to an even ical which guarantees good efficiency lev - difference is the condensing of CO 2 in the distribution of the injected CO 2. els. In the most favourable application cascade cooler, while the receiver tank In the case of a system breakdown where a range (approx. -10 to -50°C), pressures are (accumulator) only serves as a supply ves - high rise in pressure could occur, safety still on a level where already available com- sel. valves can vent the CO to the atmosphere ponents, e.g. for R410A, can be matched 2 The extremely high volumetric refrigerating with the necessary precautions. As an alter - with acceptable effort. capacity of CO 2 (latent heat through the native, additional cooling units for CO 2 con - changing of phases) leads to very low mass densation are also used where longer shut- Resulting design criteria flow rates, allows for small cross sectional off periods can be bridged without a critical pipe and minimal energy needs for the circu- pressure increase. For the high temperature side of such a lating pumps. cascade system, a compact cooling unit can For systems in commercial applications, a be used, whose evaporator serves on the There are different solutions for the combi - direct expansion version is possible as well. secondary side as the condenser for CO . nation with a further compression stage, e.g. 2 Supermarket plants with their usually widely Chlorine-free refrigerants are suitable, e.g. for low temperatures. branched pipe work offer an especially good NH , HCs or HFCs, HFO and HFO/HFC 3 Fig. 30 shows a variation with an additional potential in this regard: The medium tem - blends. receiver, which one or more booster com - perature system is carried out in a conven - With NH 3, the cascade heat exchanger pressors will bring down to the necessary tional design or with a secondary circuit, for should be designed in a way that the dread - evaporation pressure. Likewise, the dis - low temperature application combined with ed build-up of ammonium carbonate in the charge gas is fed into the cascade cooler, a CO 2 cascade system (for subcritical oper - case of leakage is prevented. This technol - condenses and is carried over to the receiv - ation). A system example is shown in Fig. 31. ogy has been applied in breweries for a er. The feeding of the low pressure receiver For a general application, however, not all long time. (LT) is achieved by a level control device. requirements can be met at the moment. It A secondary circuit for larger plants with Instead of conventional pump circulation the is worth considering that system technology CO 2 could be constructed utilising, to a booster stage can also be built as a so- changes in many respects and specially ad- wide extent, the same principles for a low called LPR system.The circulation pump is justed components are necessary to meet pressure pump circulating system, as is thus not necessary, but the number of evap - the demands.

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Fig. 30 Casacde system with CO 2 for industrial applications Fig. 31 Conventional refrigeration system combined with CO2 low temperature cascade

34 Halogen free (natural) refrigerants

The compressors, for example, must be an intermediate pressure receiver. Depend - fore still limited, but with an upward trend. properly designed because of the high ing on the temperature curve of the heat Apart from these specific applications, there vapour density and pressure levels (particu - sink, a system designed for transcritical is also a range of developments for the larly on the suction side). There are also operation can also be operated subcritically classical areas of refrigeration and air-con - specific requirements with regard to materi - ‒ with higher efficiency. In this case, the ditioning, e.g. supermarket refrigeration. als. Furthermore only highly dehydrated gas cooler becomes the condenser. Installations with parallel compounded com - CO must be used. pressors are in operation to a larger scale. 2 Another feature of transcritical operation is They are predominantly booster systems High demands are made on lubricants as the necessary control of the high pressure where medium and low temperature circuits well. Conventional oils are mostly not misci - to a defined level. This "optimum pressure" are connected (without heat exchanger). ble and therefore require costly measures is determined as a function of gas cooler The operating experience and the calculat - to return the oil from the system. On the outlet temperature by means of balancing ed energy costs show promising results. other hand, if miscible and highly soluble between the highest possible enthalpy dif - However, the investment costs are still POE are used, the viscosity is strongly ference and at once minimum compression higher than for conventional plants with reduced. Further information to lubricants work. It must be adapted to the relevant HFCs and direct expansion. see page 41 and Fig. 37, page 45. operating conditions using an intelligent modulating controller (see system example, On the one hand, the favourable energy For subcritical CO applications BITZER 2 Fig. 32). costs are due to the high degree of opti - offers two series of special compres - mized components and the system control, sors. As described before, under purely thermo - as well as the previously described advan - dynamic aspects, the transcritical operating tages regarding heat transfer and pressure Supplementary BITZER information con - mode appears to be unfavourable in terms drop. On the other hand, these installations cerning compressor selection for sub- of energy efficiency. In fact, this is true for are preferably used in climate zones permit - critical CO systems systems with a fairly high temperature level 2 ting very high running times in subcritical (see also https://www.bitzer.de) of the heat sink on the high pressure side. operation due to the annual ambient tem - However, additional measures can improve o Brochure KP-120 perature profile. Semi-hermetic reciprocating compres - efficiency, such as the use of parallel com - pression (economiser system) and/or ejec - For increasing the efficiency of CO super - sors for subcritical CO 2 applications 2 (LP/HP standstill pressures up to tors or expanders for recovering the throt- market systems and for using them in 30/53 bar) tling losses during expansion of the warmer climate zones, the technologies o Brochure KP-122 refrigerant. described above using parallel compres- sion and/or ejectors are increasingly used. Semi-hermetic reciprocating compres - Apart from that, there are application areas sors for subcritical CO 2 applications in which a transcritical process is advanta - Therefore, but also because of very (LP/HP standstill pressures up to geous in energy demand. These include demanding technology and requirements for 100 bar) heat pumps for sanitary water or drying pro - qualification of planners and service person - o Additional publications upon request cesses. With the usually very high tempera- nel, CO 2 technology cannot be regarded as ture gradients between the discharge tem - a general replacement for plants using HFC perature at the gas cooler intake and the refrigerants. Transcritical CO 2 applications heat sink intake temperature, a very low gas temperature outlet is achievable. This is Transcritical processes are characterized in facilitated by the temperature glide curve Resulting design criteria that the heat rejection on the high pressure and the relatively high mean temperature side proceeds isobar but not isotherm. Detailed information on this topic would go difference between CO vapour and sec - Contrary to the condensation process dur - 2 beyond the scope of this publication. In any ondary fluid. The low gas outlet temperature ing subcritical operation, gas cooling (desu - case, the system and control techniques leads to a particularly high enthalpy differ - perheating) occurs, with corresponding are substantially different from conventional ence, and therefore to a high system COP. temperature glide. Therefore, the heat plants. Already when considering pressure exchanger is described as gas cooler. As Low-capacity sanitary water heat pumps are levels as well as volume and mass flow long as operation remains above the critical already manufactured and used in large ratios specially developed components, pressure (74 bar), only high-density vapour quantities. Plants for medium to higher controls, and safety devices as well as suit - will be transported. Condensation only capacities (e.g. hotels, swimming pools, ably dimensioned pipework must be pro- takes place after expansion to a lower pres- drying systems) must be planned and vided. sure level – e.g. by interstage expansion in realised individually. Their number is there -

35 Halogen free (natural) refrigerants

The compressor technology is particularly For transcritical CO 2 applications, typical ambient conditions appear to be demanding. The special requirements result BITZER offers a wide range of special unfavourable. But it must be considered in a completely independent approach. For compressors. Their use is aimed at spe - that previous R134a systems are less effi - example, this involves design, materials cific applications, therefore individual cient than stationary plants of the same (bursting resistance), displacement, crank examination and assessment are capacity, because of specific installation gear, working valves, lubrication system, as required. conditions and high pressure losses in well as compressor and motor cooling. pipework and heat exchangers. With CO 2, Hereby, the high thermal load severely lim - Suplementary BITZER information con - pressure losses have significantly less influ - its the application for single-stage compres - cerning compressor selection for trans - ence. Moreover, system efficiency is further sion. Low temperature cooling requires critical CO 2 systems improved by the high heat transfer coeffi - 2-stage operation, whereby separate high and (see also https://www.bitzer.de) cients in the heat exchangers. low pressure compressors are particularly o Brochure KP-130 This is why optimized CO air conditioning advantageous with parallel compounded 2 Semi-hermetic reciprocating compres - systems are able to achieve efficiencies systems. sors for transcritical CO 2 applications comparable to those of R134a. Regarding Additional publications upon request The criteria mentioned above in connection o the usual leakage rates of such systems, a with subcritical systems apply to an even more favourable balance is obtained in higher degree for lubricants. For further CO 2 in mobile terms of TEWI. information to lubricants see page 41 and air-conditioning systems From today's viewpoint, it is not yet possible Fig. 37, page 45. to make a prediction as to whether CO can Within the scope of the long-discussed 2 Further development is necessary in vari - in the long run prevail in this application. measures for reducing direct refrigerant ous areas, and transcritical CO technology It certainly also depends on the experience 2 emissions, and the ban on the use of cannot in general be regarded as state-of- with "low GWP" refrigerants that have R134a in MAC systems within the EU, the the-art. meanwhile been introduced by the automo - development of CO systems has been 2 tive industry (see chapter R1234yf, page pursued intensively since several years. 11). Among others, operating safety, costs, At first glance, efficiency and therefore indi - and global logistics will play an important rect emissions from CO 2 systems under role.

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Fig. 32 Example of a transcritical CO 2 Booster system

36 Refrigerants for special applications

R124 and R142b Chlorine free substitutes for Alternatives for R114 as substitutes for special applications and R12B1 R114 and R12B1 Due to the limited market for systems with R227ea and R236fa are considered suitable In place of R114 and R12B1 previously extra high and low temperature applica - substitutes even though they may no longer used in high-temperature heat pumps and tions, the development of alternative refrige - be used in new installations in the EU from crane air conditioning systems, HCFCs rants and system components for these has 2020, due to their high GWP. been pursued less intensely. R124 and R142b can still be used as alter - R227ea cannot be seen as a full replace - natives in most regions outside of the EU. ment. Although tests and experience in real In the meantime, a group of alternatives for plants show favorable results, a critical tem - With these gases it is also possible to use the CFC R114 and Halon R12B1 (high tem - perature of 102°C limits the condensing long proven lubricants, preferably mineral perature), R13B1, R13 and R503 (extra low temperature to 85..90°C with conventional oils and alkyl benzenes with high viscosity. temperature) have been offered as replace - plant technology. Because of their ozone depleting potential, ments. On closer examination, however, the these refrigerants will only be an interim thermodynamic properties of the alterna- R236fa provides the more favourable condi - solution. In the EU member states as well tives differ considerably from the previously tions at least in this regard – the critical as in some other regions, the application used substances. This can cause costly temperature is above 120°C. A disadvan- of HCFCs is no longer allowed. For R124 changes especially with the conversion of tage, however, is the lower volumetric re- and R142b the same restrictions are valid existing systems. frigerating capacity. It is similar to R114 and as for R22 (page 8). The flammability of 40% below the performance of R124, which R142b and the resulting safety implications is still widely used for extra high tempera- should also be considered (safety group ture applications. A2). R600a (Isobutane) will be an interesting alternative where safety regulations allow Resulting design criteria/ the use of hydrocarbons (safety group A3). Converting existing plants With a critical temperature of 135°C, con - Compared to R114, the alternatives have densing temperatures of 100°C and more lower boiling temperatures (approx. -10°C), are within reach. The volumetric refriger- which results in larger differences in the ating capacity is almost identical to R124. pressure levels and volumetric refrigerating capacities. This leads to stronger limitations The "Low GWP" refrigerant R1234ze(E) in the application range at high evaporating (page 24) can also be regarded as a poten - and condensing temperatures. tial candidate for extra high temperature applications. Compared to R124, its refrige - Converting an existing installation will in rating capacity is 10 to 20% higher, its pres - most cases necessitate the exchange of the sure level about 25% higher. At identical compressor and control devices. Owing to refrigerating capacities, the mass flow dif - the lower volume flow (higher volumetric fers only slightly. Its critical temperature is refrigerating capacity), adjustments to the 109°C, which would enable an economical evaporator and the suction line may be operation up to a condensing temperature required. of about 90°C. However, like R1234yf, R1234ze(E) shows low flammability and Over the previous years BITZER com - therefore classified into the new safety pressors have been found to be well group A2L. The corresponding safety regu - suited with R124 and R142b in actual lations must be observed. installations. Depending on the applica - tion range and compressor type modifi - As no sufficient operating experience is cations are necessary, however. Perfor - available so far, the suitability of this refrige - mance data including further design rant for long-term use cannot be assessed instructions are available on request. yet.

37 Refrigerants for special applications

For high temperature heat pumps in pro - series of other fluids are possible, depend - Screw and scroll compressors can be cess technology and special applications at ing on the temperature level of the heat adapted by construction as an expander high temperatures, the low pressure refriger- source and heat sink. for ORC systems. BITZER has been ants based on HFO and HCFO developed involved in various projects for several They include the so far mostly used R245fa primarily for systems with turbo compres - years and has already been able to gain (GWP 1050) with a critical temperature of sors are also potentially suitable (page 24). important insights with this technology, 154°C and a boiling temperature of 15.1°C. which have been implemented in the They are characterised by very high critical Solvay offers further refrigerants for ORC design of screw expanders and their temperatures (> 130°C), which enable eco - applications, containing the base compo - application. An individual expander nomical operation at condensing tempera- nent R365mfc. A product with the trade design is available upon request. tures of sometimes well above 100°C. How- name Solkatherm ® SES36 already pre- ever, only purpose-built compressors and A comprehensive description of ORC sented several years ago contains perfluoro- system components can be used here. systems would go beyond the scope of polyether as a blend component. It is an this Refrigerant Report. Further informa - Another advantage is their very low GWP azeotropic blend with a critical temperature tion is available upon request. and the classification in safety group A1 of 178°C. Meanwhile two zeotropic blends (non-flammable, non-toxic). containing R365mfc and R227ea have been developed whose critical temperatures are A detailed evaluation of these refrigerants is 177°C and 182°C, due to different mixing not yet possible with respect to the chemi - ratios. They are available under the trade cal stability of the refrigerants and of the names Solkatherm ® SES24 and SES30. lubricants at the very high operating tem - In ORC systems zeotropic behavior may be peratures and the long service life required advantageous. In the case of single-phase for industrial systems. heat sources and heat sinks, the tempera - Special applications also include cogenera - ture difference at the so-called "pitch point" tion systems – "Organic Rankine Cycle" can be raised by the gliding evaporation (ORC) , which become increasingly impor - and condensation. This leads to improved tant. In addition to the potentially suitable heat transmission due to the higher driving substances listed in the table above, a average temperature difference.

09.20 Refrigerant Type Composition GWP Safety Boiling Critical (with blends) AR4 (AR5) Group temperature [°C] temperature [°C]

R1224yd(Z) HCFO 4 (1) A1 14.6 156

R1233zd(E) HCFO 5 (1) A1 18.3 166

R1336mzz(E) HFO – (7) A1 7.6 130

R1336mzz(Z) HFO 9 (2) A1 33.5 171

R514A HFO R1336mzz(Z)/R1130(E) 7 (2) A1 28.8 178

Tab. 6 Characteristics of HFO (HCFO) low-pressure refrigerants

38 Refrigerants for special applications

Alternatives for R13B1 In addition to this, the steep fall of pressure only limited experience has been gained limits the application at very low tempera - even for typical low temperature refrigera - tures and may require a change to a cas - tion. Besides R410A, ISCEON ® MO89 (DuPont) cade system with e.g. R23, R508A/B or can be regarded as potential R13B1 substi - At evaporating temperatures of down to R170 (ethane) in the low temperature tute. For R410A, a substantially higher dis - -50..-52°C, operation with CO is also stage. 2 charge gas temperature than for R13B1 is possible − either in a two-stage or a cas - to be considered, which restricts the appli - Lubrication and material compatibility are cade system. cation range even in 2-stage compression similar to other HFC blends. However, each variant generally requires a systems to a greater extent. The EU F-Gas Regulation (Annex III) pro - specific design and laboratory tests. ISCEON ® MO89 has been used for many vides an exemption "for applications years, preferably in freeze-drying plants. designed to cool products below -50°C". Meanwhile, production has ceased. Howev - This means that even after 2020, refriger- er, for historical reasons the refrigerant will ants with GWP > 2500 can be used in new continue to be included in this Report. It is a plants. Due to the "phase-down" however, mixture of R125 and R218 with a small pro - quantities will be limited, resulting in a con - portion of R290. Due to the properties of siderable increase in price and very limited the two main components, density and availability. mass flow are relatively high, and discharge It is therefore imperative to develop alterna - gas temperature is very low. Liquid subcool - tive solutions for which, however, no overall ing is of particular advantage. recommendation is possible. Two-stage Both of the mentioned refrigerants have compressors may be operated e.g. with fairly high pressure levels and are therefore R448A/449A (safety group A1) or R1270 limited to 40..45°C condensing temperature (A3) down to an evaporation temperature of with the usually applied 2-stage compressors. -60..- 65°C. Although R404A/ R507A alter - They also show less capacity than R13B1 natives with GWP < approx. 250 (safety at evaporating temperatures below -60°C. group A2L) are potentially possible, so far

  

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 Fig. 33 R13B1/HFC alternatives – comparison of discharge gas temperatures of a 2-stage compressor 39 Refrigerants for special applications

Alternatives for R13 possible or would involve unjustifiable cations up to about -80°C evaporating tem - and R503 expenses and high costs in the relevant perature? special applications. At first glance, these are very positive fea - Following these challenges, the company tures. Unfortunately, there are also nega- For these substances, the situation is still Weiss Technik in cooperation with the TU tive aspects that virtually preclude the use quite favorable from a purely technical Dresden has developed a non-flammable of N 2O as a pure substance. point of view; they can be replaced by R23 (A1) refrigerant mixture of R32, R125 and Pure N O as a refrigerant is a safety risk: It and R508A/R508B. R170 (ethane) is also CO , which has proven to be a well suited 2 2 has a narcotic effect and promotes fire. suitable if the safety regulations allow a alternative to R23, e.g. when used in so- N O can oxidize other substances. In addi - flammable substance (safety group A3). called climatic stress chambers. It is mar - 2 tion, under specific conditions (pressure, keted under the trade name WT69 and sold Due to the partly steeper pressure curve of temperature or ignition source), exothermic by TEGA Technische Gase. The refrigerant the alternative refrigerants and the higher decomposition reactions can occur, which is now also listed in the ASHRAE nomen - discharge gas temperature of R23 com- fundamentally call into question the perma - clature under R469A. pared to R13, differences in performance nently safe operation of a refrigeration and application ranges for the compressors A major advantage over R23 is that the system with pure N 2O. must be considered. Heat exchangers and GWP is reduced by more than 90% (1398). By adding CO in higher percentages (over controls have to be adapted individually. This ensures at least medium to longer- 2 approx. 15%), the triple point is slightly term availability. As lubricants for R23 and R508A/B, polyol shifted towards higher temperatures, but at ester oils are suitable, but must be From a thermodynamic point of view, there the same time a positive effect ("phlegmati - matched for the special requirements at are major differences to R23, therefore the zation") on oxidation and chemical decom- extreme low temperatures. suitability in the respective application must position is achieved. The safety risk is be checked individually. Although the diffe - reduced significantly, and material compati - R170 is also well soluble with conventional rences in the boiling point are not large bility is considerably improved. Neverthe - oils, but an adaptation to the temperature (-78.5°C vs. -82°C for R23), the mixture less, there are special challenges i.a. for will be necessary. features a distinct temperature glide. Apart lubricants with a high resistance to oxida - Applications with these refrigerants are from the required specific design of the tion which must also be suitable for the purely for cooling products below -50°C. heat exchangers, this may affect the oper- special requirements at low temperature Hence, the exemption described in the pre - ating process and the compressor size. conditions. vious chapter in the EU F-Gas Regulation Furthermore, research projects have been Investigations are ongoing. A final assess - applies in particular. initiated that examine the use of N 2O ment is not yet possible, which is why no For R23 and R508A/B, however, the (nitrous oxide) and mixtures of N 2O and guidelines can currently be drawn up for effects of "phase-down" are particularly CO 2 are examined in more detail. Extensive the design and implementation of such serious. The GWP values range from examinations and tests at the Karlsruhe systems. 13200 to 14800 (AR4). Even relatively University of Applied Sciences and the small quantities are therefore very much at Institute of Air Handling and Refrigeration BITZER has carried out investigations the expense of the available quotas. (ILK) in Dresden show revealing results. and also collected experiences with Apart from R170 (ethane) with the special N2O (R744A) has similar thermodynamic several of the substitutes mentioned. safety precautions required for A3 refriger- properties and pressures as CO 2, identical Performance data and instructions are ants, there are no directly comparable molecular weight, a very low triple point available upon request. Due to the indi - alternatives for R23 and R508A/B within (-90.8°C) and a critical temperature of vidual system technology for these the group of HFOs or HFO/HFC mixtures 36.4°C. The GWP is 298, which is a frac - special installations, consultation with (safety groups A1 or A2L). In many cases, tion of the R23 and R508A/B values. In BITZER is necessary. however, the use of A3 refrigerants is not sum, an ideal alternative for special appli -

40 Lubricants

Lubricants for compressors are therefore less suitable for semi-herme - (Ammonia) as alternative refrigerant (page tic and hermetic compressors. They are 28) and supplementary information (see primarily used in mobile air conditioning below). systems with open drive compressors, Positive displacement compressors ‒ as Further information see Fig. 37 “Overview where special requirements for lubrication are predominantly used in commercial and lubricants”, page 45 and explanations for and best solubility/miscibility are required industrial refrigeration, air conditioning and the particular refrigerants. because of a high oil circulation rate. To heat pump systems ‒ are commonly oil- avoid copper plating, non-ferrous metals lubricated. Despite appropriate construc- Supplementary BITZER information con - are used in these systems. tional measures and/or installation of an oil cerning lubricants separator, a small amount of oil is pumped The remaining refrigeration industry so far (see also https://www.bitzer.de) into the circuit together with the compress- prefers POE oils. The extensive experience o Technical Information KT-500 ed gas flow. To stabilise the oil balance, gained with them is positive if the water „BITZER refrigeration compressor suitable measures for continuous oil return content in the oil does not significantly oils for reciprocating compressors” must be taken. Oils that are soluble and exceed 100 ppm. However, only oils speci - o Technical Information ST-500 miscible with the refrigerant are advantage - fied by the compressor manufacturer may „BITZER refrigeration compressor ous. The refrigerant dissolved in the oil sig - be used. Because of the increased reactivi - oils for screw compressors“ nificantly reduces the viscosity, improving ty of HFOs with oil, this is especially true o Technical Information EST-500 oil fluidity and minimising the negative for systems with these refrigerants. „BITZER refrigeration compressor influence on heat transfer in heat exchan - Compressors for factory-made air conditio - oils for scroll compressors – statio - gers. ners and chillers are also increasingly nary applications" In the past, so-called naphthenic mineral being charged with polyvinyl ether (PVE) o Technical Information AT-640 oils and synthetic alkylbenzenes were pre - oils. Although they are more hygroscopic „Use of ammonia (R717) in BITZER ferred. For systems with CFC and HCFC than POE, they are very resistant to hydro - compressors” – chapter: "Oils and refrigerants (for example R22) and hydro - lysis, thermally and chemically stable, have their influence on the system design" carbons, they are very favorable with good lubricating properties and high dielec - o Technical Information AT-660 regard to solubility and miscibility. On the tric strength. In contrast to POE, they are „Use of propane (R290) and propene other hand, owing to their low polarity, they less prone to the formation of metal soaps (R1270) in semi-hermetic BITZER are insufficiently miscible with the highly and thus offer more security against block- compressors” – chapter: "Oils“ polar HFC and HFO refrigerants and are age of capillaries. o Operating Instructions KB-120 and therefore not properly and sufficiently KB-130 Special requirements for the lubricants drawn into the refrigeration cycle. „Semi-hermetic reciprocating com - exist with CO systems. Specially formulat- 2 pressors for CO applications“ Immiscible oils can accumulate in the heat ed POEs are also suitable for use in widely 2 exchangers and hinder the heat transfer so ramified pipe networks due to their particu - much that operation of the system is no larly good solubility/miscibility. However, longer possible. these properties have a negative effect on viscosity and lubricity (tribology) and there - Therefore, new lubricants with appropriate fore require compressors with an extremely solubility/miscibility have been developed robust and wear-resistant drive gear. At for systems with HFC and HFO refriger- very high loads, e.g. heat pumps, PAG oils ants. These are oils based on polyol ester specially developed for CO applications (POE) and polyalkylene glycol (PAG). 2 ensure even more favorable lubrication They have similar or better lubricating pro - conditions. perties than previously customary oils, but Due to the thermodynamic properties of are more or less hygroscopic, depending ammonia (NH ) and the resulting plant on the refrigerant solubility. This requires 3 engineering, non-soluble/miscible oils are special care in manufacturing (including advantageous. These include for example drying), transport, storage and charging, so mineral oils and polyalphaolefins (PAO). that chemical reactions in the plant – such However, they require a special technique as hydrolysis in POE – are avoided. for oil separation and oil recirculation. For PAG-based oils are particularly critical con - further explanation as well as additional cerning water absorption. In addition, they information on applications when using par - have a relatively low dielectric strength and tially soluble PAG oils see chapter NH 3

41 Refrigerant properties

09.20 5 6 Refrigerant Composition Substitute / Application ODP GWP (100a) Safety Practical type (Formula) Alternative range group 4 limit 3 5 for [R11=1.0] [CO 2=1.0] [kg/m ] AR4 (AR5) HCFC-Refrigerants 5 1 R22 CHClF 2 R502 (R12 ) 0.055 1810 (1760) A1 0.3 R124 CHClFCF 0.022 609 (527) A1 0.11 3 R114 1 , R12B1 R142b CCIF 2CH 3 0.065 2310 (1980) A2 0.049 HFC Single-component Refrigerants 1 R134a CF 3CH 2F R12 (R22 ) 1430 (1300) A1 0.25 R152a CHF 2CH 3 mainly used as 124 (138) A2 0.027 R125 CF 3CHF 2 part components 3500 (3170) A1 0.39 R143a CF 3CH 3 for blends see 4470 (4800) A2L 0.048 R32 CH 2F2 R410A (R22) page 44 0 675 (677) A2L 0.061 1 R227ea CF 3-CHF-CF 3 R12B1, R114 3220 (3350) A1 0.63 R236fa CF 3-CH 2-CF 3 R114 9810 (8060) A1 0.59

R23 CHF 3 R13 (R503) 14800 (12400) A1 0.68 HFC Blends R404A R143a/125/134a 3922 (3940) A1 0.52 R507A R143a/125 3985 (3990) A1 0.53 R407A R32/125/134a 2107 (1920) A1 0.33 R407F R32/125/134a R22 (R502) 1825 (1670) A1 0.32 R407H R32/125/134a 1490 (1380) A1 0.38 R422A R125/134a/600a 3143 (2850) A1 0.29 R437A R125/134a/600/601 R12 (R500) 1805 (1640) A1 0.081 R407C R32/125/134a 1774 (1620) A1 0.31 see 0 R417A R125/134a/600 page 44 2346 (2130) A1 0.15 R417B R125/134a/600 2920 (2740) A1 0.069 R422D R125/134a/600a R22 2729 (2470) A1 0.26 R427A R32/125/143a/134a 2138 (2020) A1 0.29 R438A R32/125/134a/600/601a 2264 (2060) A1 0.079 R410A R32/125 R22 1 (R13B1 2 ) 2088 (1920) A1 0.44

R508A R23/116 R503 13210 (11600) A1 0.23 R508B R23/116 13400 (11700) A1 0.25 HFOs and HFO/HFC Blends – further blends and data see pages 24 to 27

R1234yf CF 3CF=CH 2 4 (< 1) A2L 0.058 R1234ze(E) CF 3CH=CHF 7 (< 1) A2L 0.061 R513A (XP10) R1234yf/134a R134a 631 (573) A1 0.35 R450A (N-13) R1234ze(E)/134a 605 (547) A1 0.319 R471A R1234ze(E)/1336mzz(E)/227ea 148 (148) A1 N/A R134a 1 R515B R1234ze(E)/227ea see 293 (299) A1 0.29 0 R448A (N-40) R32/125/1234yf/1234ze(E)/134a page 44 1387 (1270) A1 0.388 R449A (XP40) R32/125/1234yf/134a 1397 (1280) A1 0.357 R404A, R507A R454C R32/1234yf 148 (146) A2L 0.059 R455A R32/1234yf/CO 2 148 (146) A2L 0.105 R452B R32/125/1234yf 698 (676) A2L 0.062 R410A R454B R32/1234yf 466 (467) A2L 0.061 Halogen free Refrigerants

R717 (NH 3) NH 3 R404A (R22) 0 B2L 0.00035 R723 NH 3/R-E170 R404A (R22) 1 B2 N/A 1 R600a C4H10 R134a 3 A3 0.011 R290 C H R404A (R22) 3 A3 0.008 3 8 see 0 R1270 C3H6 R404A (R22) page 44 2 A3 0.008 R170 C2H6 R23 6 A3 0.008

R744 (CO 2) CO 2 Diverse 1 A1 0.07

Tab. 7 Refrigerant properties (continued on Tab. 8)

These data are valid subject to reservations; they are based on information published by various refrigerant manufacturers. 1 Alternative refrigerant has larger deviation in 3 Also used as a component in R290/ 6 AR4: according to IPCC IV – time horizon 100 years – refrigerating capacity and pressure 600a-Blends (direct alternative to R12) also basis for EU F-Gas Regulation 517/2014 AR5: according to IPCC V – time horizon 100 years 2 Alternative refrigerant has larger deviation 4 Classification according to EN 378-1 below -60°C evaporating temperature and ASHRAE 34 N/A Data not yet published.

5 According to EN 378:2016

42 Refrigerant properties

09.20 Refrigerant Boiling Temperature Critical Cond. temp. Refr. Discharge Lubricant type temperature glide temperature at 26 bar capacity gas temp. (compressor) [°C] 1 [K] 2 [°C] 1 (abs) [°C] 1 [%] 3 [K] 3

HCFC-Refrigerants R22 -41 0 96 63 80 (L) 4 +35 4 R124 -12 0 122 105 5 5 R142b -9 0 137 112 HFC Single-component Refrigerants R134a -26 0 101 79 97 (M) -8 R152a -24 0 113 85 R125 -49 0 66 51 5 5 R143a -47 0 73 55 R32 -52 0 78 42 108 (H) +21 R227ea -16 0 102 96 5 5 R236fa -2 0 125 115

R23 -82 0 26 2 5 5 HFC Blends R404A -46 0.7 72 56 105 (M) -34 R507A -47 0 71 54 107 (M) -34 R407A -45 6.5 82 59 98 (M) -19 R407F -46 6.4 83 57 104 (M) -11 R407H -45 7.0 87 60 99 (M) -8 R422A -47 2.5 71 55 100 (M) -39 R437A -32 3.5 95 75 108 (M) -7 R407C -44 7.1 86 61 100 (H) -8 R417A -39 5.0 85 67 97 (H) -25 R417B -45 3.4 74 58 95 (M) -37 R422D -43 4.9 78 62 90 (M) -36 R427A -43 6.8 85 63 90 (M) -20 R438A -42 6.2 83 64 88 (M) -27 see page 45 R410A -51 0 71 43 140 (H) -4 R508A -88 0 10 -3 5 5 R508B -88 0 11 -3 HFO and HFO/HFC Blends – further blends and data see pages 24 to 27 R1234yf -30 0 95 82 98 (M) -14 R1234ze(E) -19 0 109 92 75 (H) -6 R513A (XP10) -30 0 95 78 102 (M) -7 R450A (N-13) -23 0.6 104 86 88 (M) -6 R471A -17 3.2 112 97 67 (H) -7 R515B -19 0 109 93 75 (H) -7 R448A (N-40) -46 6.2 83 58 96 (M) +12 R449A (XP40) -46 5.7 82 58 96 (M) +12 R454C -46 7.8 86 64 86 (M) +7 R455A -52 12.9 86 61 93 (M) +10 R452B -51 0.9 77 46 98 (H) +7 R454B -51 1.0 78 47 97 (H) 0 Halogen free Refrigerants

R717 (NH 3) -33 0 132 60 100 (M) +60 R723 -37 0 131 58 105 (M) +35 R600a -12 0 135 115 55 (H) -9 R290 -42 0 97 70 86 (M) +4 R1270 -48 0 91 61 104 (M) +12

R170 -89 0 32 4 5 5 6 R744 (CO 2) -57 0 31 -11 5 5

Tab. 8 Refrigerant properties

1 Rounded values 3 Reference refrigerant for these values 4 Valid for single stage compressors is stated in Tab. 7 under the nomina- 2 Total glide from bubble to dew line – tion "Substitute for " (column 3) 5 Data upon request (operating conditions based on 1,013 bar (abs.) pressure. Letter within brackets indicates must be given) Real glide dependent on operating operating conditions 6 Triple point at 5.27 bar conditions. H High temp (+5/50°C) Approx. values in evaporator: M Medium temp (-10/45°C) Stated performance data are average values H/M 70%; L 60% of total glide L Low temp (-35/40°C) based on calorimeter tests. 43 Application ranges

HFC refrigerants

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Fig. 34 Application ranges for HFC refrigerants (ODP = O)

"Low GWP" refrigerants (HFO, HFO/HFC blends, R32)



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Fig. 35 Application ranges for "Low GWP" refrigerants (HFO, HFO/HFC blends, R32) 44 Application ranges

Halogen free refrigerants

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Fig. 36 Application ranges for halogen free refrigerants

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Fig. 37 Lubricants for compressors 45 REFRIGERANT REPO RT 21

A-501-21 EN

BITZER Kühlmaschinenbau GmbH Peter-Schaufler-Platz 1 // 71065 Sindelfingen // Germany Tel +49 7031 932-0 // Fax +49 7031 932-147 [email protected] // www.bitzer.de

Subject to change // 80050206 // 09.2020

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