Further development projects with "Low GWP" refrigerants

For specific applications, Chemours has developed a non-flammable (A1) R410A alternative, which is marketed in selected countries and regions under the trade name OpteonTM XP41 – listed by ASHRAE as R463A.

It is a mixture of R32, R125, R1234yf, R134a and CO2 with a GWP of 1494. Despite the high proportion of R32 and R1234yf, flammability is suppressed by mixing with R125, R134a and CO2.

Regarding thermodynamics, the differences to R410A are comparatively small. The addition of CO2, however, leads to a distinct temperature glide, which may cause certain limitations for the application and places particular demand on the design of the heat exchangers.

All mixture components and their properties are well known, which means there are no additional particularities regarding material compatibility in comparison to the already known R410A alternatives.

The supply of compressors for laboratory or field tests requires an individual review of the specific application and a special agreement.

Some time ago, Honeywell has unveiled the new development of a non-flammable (A1) R410A alternative under the trade name Solstice® N-41 – listed by ASHRAE as R466A.

R466A is a mixture of R32, R125 and R13I1 (CF3I − tri-fluoroiodomethane), an iodine-methane derivative not previously used in refrigeration. CF3I is not flammable, as is R125, which means that the refrigerant is not flammable (A1), even with the relatively high proportion of R32 (A2L).

Despite the noticeable proportion of R125 with a GWP of 3500, the total GWP is 733 (AR4) and therefore in the range of R32 and R452B, which are however classified as A2L.

From a thermodynamic point of view, the differences between R410A and R466A are relatively small. Volumetric refrigerating capacity, pressure levels and discharge temperature are slightly higher, the refrigerant mass flow deviates slightly more (about 15 to 20% higher). The temperature glide is also very low.

Hence, R466A appears to be a promising substitute for R410A. However, due to the CF3I share, there are still uncertainties regarding long-term chemical stability and material compatibility under the special requirements of the refrigeration cycle.

Further investigation is required, so a final assessment of R466A is currently not possible. In any case, as matters stand, this refrigerant cannot be used in state-of-the-art systems (retrofit). The supply of compressors for laboratory tests requires an individual review of the specific application as well as a special agreement.

AGC Chemicals propagates R1123 ( CF2=CHF) mixed with R32, partially with addition of R1234yf, as an alternative to R410A and pure R32. It is a HCFO with very low ozone depletion potential (ODP). R1123 has a significantly higher volumetric refrigeration capacity than R1234yf or R1234ze(E) and is advantageous in this respect. However, the pressure level is even higher than of R32 and the critical temperature is only about 59°C. Apart from that, there are unanswered questions about the chemical long-term stability under the special requirements of the refrigeration cycle. According to the safety data sheet, this substance is also subject to very stringent safety requirements.

A final assessment of these mixtures is therefore currently not possible.

Comment from a compressor manufacturer’s point of view

It should be an aim to limit the product variety currently becoming apparent and to reduce the future supply to a few "standard refrigerants". It will not be possible for component and equipment manufacturers nor for installers and service companies to deal in practice with a larger range of alternatives.

Potential mixture components for "Low GWP" alternatives (examples) (status as of 09.2020)
①: refrigerating capacity, mass flow, discharge gas temperature similar to R404A
②: only low percentage – due to temperature glide (CO2) and flammability (R290)
③: R32/HFO blends show lower refrigerating capacity than reference refrigerant, the addtion of CO2 leads to high temperature glide
④: approx. values according to IPCC IV (AR4)
⑤: R13I1 (CF3I − tri-fluoroiodomethane) is an iodine-methane derivative.
⑥: Lower volumetric refrigerating capacity than reference refrigerant

Current HFC refrigerants

Alternatives

Components / Mixture components for "Low GWP" alternatives (examples)

Safety
Group

GWP④

R1234yf
A2L

GWP 4

R1234ze(E)
A2L

7

R32
A2L

675

R152a
A2

124

R134a
A1

1430

R125
A1

3500

R13I1
A1
<1

R227ea
A1

3220

R1336mzz(E)
A1

7

CO2
A1
1

R290
A3
3

R134a
GWP 1430

A1

~ 600

A1

~ 300⑥

A1

< 150⑥

A2L

< 150

A2L

< 10

R404A/ R507A
GWP 3922/ 3985

A1

< 2500①

A1

~ 1400

A2L

< 250

A2L③

< 150

A2

< 150

R22/ R407C
GWP 1810/ 1774

A1

900 .. 1400

A2L

< 250

A2L

< 150

A2

< 150

R410A
GWP 2088

A1

< 1500

A1

< 750

A2L

< 750

A2L

~ 400..750

"Low GWP" alternatives for HFC refrigerants (status as of 09.2020) - further data: Refrigerant data
①: The relatively low GWP of R134a allows its use also on longer term.
②: lower volumetric refrigerating capacity than reference refrigerant
③: AR4: according to IPCC IV // AR5: according to IPCC V – time horizon 100 years
④: rounded values
⑤: total glide from bubble to dew line at 1.013 bar (abs.)
⑥: development product

Current HFC refrigerants

"Low GWP" alternatives for HFC refrigerants

ASHRAE number

Trade Name

Composition
(with blends)

GWP
AR4 (AR5)

Safety
Group

Boiling
Temperature
in °C

Temperature
Glide
in K

R134a
GWP 1430 ①

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

R513A

OpteonTM XP10

Chemours

R1234yf/ 134a

631 (573)

A1

-30

0

R513A

Daikin Chemical

R515B ②

Honeywell

R1234ze(E)/ 227ea

293 (299)

A1

-19

0

R471A ②

Honeywell

R1234ze(E)/ 1336mzz(E)/ 227ea

148 (148)

A1

-17

2.4

R1234yf

various

4 (< 1)

A2L

-30

0

R1234ze(E)

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/ 152a/ 134a

142 (131)

A2L

-29

0

R404A/
R507A

GWP 3922/3985

 

(R22/R407C)

R448A

Solstice® N-40

Honeywell

R32/ 125/ 1234yf/ 1234ze(E)/ 134a

1387 (1273)

A1

-46

6.2

R449A

OpteonTM XP40

Chemours

R32/ 125/ 1234yf/ 134a

1397 (1282)

A1

-46

5.7

Forane® 449

Arkema

R452A

OpteonTM XP44

Chemours

R32/ 125/ 1234yf

2140 (1945)

A1

-47

3.8

R454A

OpteonTM XL40

Chemours

R32/ 1234yf

239 (238)

A2L

-48

5.7

R454A

Daikin Chemical

R457B

ARM-20b

Arkema

R32/ 1234yf/ 152a

251 (251)

A2L

-47

6.1

R454C

OpteonTM XL20

Chemours

R32/ 1234yf

148 (146)

A2L

-46

7.8

R455A

Solstice®
L-40X

Honeywell

R32/ 1234yf/ CO2

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

R22/R407C
GWP 1810/1774

R449C

OpteonTM XP20

Chemours

R32/ 125/ 1234yf/ 134a

1251 (1146)

A1

-44

6.1

R410A
GWP 2088

R32

various

675 (677)

A2L

-52

0

R452B

OpteonTM XL55

Chemours

R32/ 125/ 1234yf

698 (676)

A2L

-51

0.9

Solstice® L-41y

Honeywell

R454B

OpteonTM XL41

Chemours

R32/ 1234yf

466 (467)

A2L

-51

1.0

R463A

OpteonTM XP41

Chemours

R32/ 125/ 1234yf/ 134a/ CO2

1494 (1377)

A1

-59

12.2

R466A

Solstice® N-41

Honeywell

R32/ 125/ 13I1 (CF3I)

733 (696)

A1

-52

0.7