Oils for HFC and HFO refrigerants

BITZER compressors which are intended for use with chlorine-free HFC and HFO refrigerants (R134a, R404A, R407A/C/F, R507A, R1234yf, R513A, R450A etc.) are charged with a high-quality polyolester oil. In these cases, a “Y” is added to the type designation of the compressor. BITZER polyolester oils significantly exceed the requirements of DIN 51503, Part 1, for refrigeration compressor oils with respect to water content and total acid number (TAN). They mix well with HFC and HFO refrigerants and are therefore especially suitable for operation with these substances.

Characterising the oils

Bitzer oils for HFC and HFO refrigerants in reciprocating compressors

Oil

Oil type

Applications

Designation on compressor

BSE32

polyolester oil (POE)

standard oil charge

"Y" (e.g. 2CES‑4Y)

BSE55

polyolester oil (POE)

alternative oil charge for condensing temperature tc > 70°C (available for many compressors)

"Y" (e.g. 2CES‑4Y)

BSE85K

polyolester oil (POE)

oil charge for special applications

"Y" (e.g. 2CES‑4Y)

Initial charge only with original oils

Risk of compressor damage!

Risk of compressor damage!

BITZER polyolester oils are mandatory for the running-in period of the compressor. Use only these oils for the initial charge!

BITZER polyolester oils are characterised by specific tribological characteristics and have special wear protection additives which increase the service life of the compressor. The use of alternative oils whose characteristics correspond largely to the original charge is only possible at the system owner’s own responsibility. It is possible to mix them with the original oil, within the respective viscosity group, as long as appropriate own or comparable experience is available for the application concerned. Generally, mixing different oil types may have a negative effect on the properties of the oils. Precondition for the use of alternative oils is that the manufacturer or supplier guarantees product quality and moisture content < 50 ppm.

BITZER will only use BITZER polyolester oils for the complex tests of compatibility with new materials and refrigerants. In case of material changes on products, only BITZER polyolester oils will be included in the tests.

Low GWP refrigerants: stricter requirements for refrigeration systems

Many refrigerant blends with low global warming potential (GWP) such as R448A, R449A, R450A, R452A and R513A contain the unsaturated compounds R1234yf and R1234ze(E). Part of them are highly soluble in oil and lead to a strong reduction of viscosity. Therefore, sufficient superheat has to be ensured! The low chemical stability (which is desirable for a low GWP) requires particular care regarding cleanliness, dryness and evacuation of the refrigerant circuit.

Material safety data sheets

Apart from this document, please observe the material safety data sheet (MSDS) for the respective oil. It contains information on toxicity, handling, personal protective equipment and disposal of the oil. Material safety data sheets for all Bitzer oils are available on request.

Application range

Application range of polyolester oils (POE) for HFC and HFO refrigerants in Bitzer reciprocating compressors. For application limits see also Bitzer Software.
to: evaporation temperature
tc: condensing temperature
(✔): after consultation with Bitzer Application Engineering

Oil

suitable e.g. for
refrigerants

Application range

cooling with to ≤ 25°C

air conditioning

medium temperature application

low temperature application

BSE32
tc ≤ 70°C

R134a
R513A
R1234yf


✔


✔


✔


(✔)

R450A

✔

✔

✔

– –

R404A
R448A
R449A
R452A
R407A / F



– –



(✔)



✔



✔

R407C

– –

✔

✔

– –

R507A

– –

(✔)

✔

✔

BSE55
tc ≤ 70°C

R1234ze(E)

– –

✔

✔

– –

BSE55
tc even > 70°C

R134a
R513A
R1234yf


✔


✔


✔


(✔)

R450A

✔

✔

✔

– –

R407C

– –

✔

✔

– –

R410A

– –

✔

✔

(✔)

BSE85K

R1234ze(E) at to > 15°C or tc > 70°C.
Other refrigerants: special application after consultation with Bitzer Application Engineering.

Technical data

Technical data of oils for HFC and HFO refrigerants in Bitzer reciprocating compressors

BSE32

BSE55

BSE85K

Unit

Density at 15°C

1.006

1.010

0.993

g/ml

Flashpoint

247

280

246

°C

Pour point

-57

-51

-42

°C

Kinematic viscosity

at 20°C

74

147

200

cSt

at 40°C

32

55

80

cSt

at 100°C

6

9

11

cSt

Specific heat capacity

at 40°C

1.94

1.92

1.89

kJ/kg*K

at 100°C

2.12

2.09

2.05

kJ/kg*K

Thermal conductivity

at 40°C

0.15

0.15

0.14

W/m*K

at 100°C

0.14

0.14

0.13

W/m*K

Miscibility gaps BSE32

Miscibility gaps for oil BSE32: Limit temperature depending on oil content (mass % of oil in oil refrigerant blend).M: Range of complete miscibility.P: Phase separation range (miscibility gap).
Miscibility gaps for oil BSE32: Limit temperature depending on oil content (mass % of oil in oil refrigerant blend).
M: Range of complete miscibility.
P: Phase separation range (miscibility gap).

Miscibility gaps BSE55

Miscibility gaps for oil BSE55: Limit temperature depending on oil content (mass % of oil in oil refrigerant blend).M: Range of complete miscibility.P: Phase separation range (miscibility gap).
Miscibility gaps for oil BSE55: Limit temperature depending on oil content (mass % of oil in oil refrigerant blend).
M: Range of complete miscibility.
P: Phase separation range (miscibility gap).

Refrigerant solubility in BSE32

The following diagrams can be used to read off the refrigerant content in the lubricant depending on refrigerant pressure and oil temperature.

Oil BSE32: Refrigerant pressure depending on oil temperature and refrigerant content (mass % of refrigerant in oil-refrigerant blend).
Oil BSE32: Refrigerant pressure depending on oil temperature and refrigerant content (mass % of refrigerant in oil-refrigerant blend).

Refrigerant solubility in BSE55

Oil BSE55: Refrigerant pressure depending on oil temperature and refrigerant content (mass % of refrigerant in oil-refrigerant blend).
Oil BSE55: Refrigerant pressure depending on oil temperature and refrigerant content (mass % of refrigerant in oil-refrigerant blend).

Warning values for used oils

The listed polyolester oils are categorized as group KD according to DIN51503, Part 1. To determine the used condition of the oil, e.g. with respect to water content or total acid number (TAN), the reference values of DIN 51503, Part 2, apply.

Warning values for used Bitzer oils for HFC and HFO refrigerants.
(*): that is ± 15% of the value for new oil

Oil

Kinematic viscosity at 40°C (DIN EN ISO3104)

Max. water content
(DIN51777-2)

Total acid number
(DIN51558-1)

BSE32

outside of 27 .. 37 cSt (*)

200 mg H2O/kg oil

0.2 mg KOH/g

BSE55

outside of 47 .. 63 cSt (*)

200 mg H2O/kg oil

0.2 mg KOH/g

BSE85K

outside of 68 .. 92 cSt (*)

200 mg H2O/kg oil

0.2 mg KOH/g

When using A2L refrigerants:

Fire hazard!

Fire hazard!

The used oil contains a relatively large amount of dissolved refrigerant.

Pack used oil safely. Dispose of in an environmentally friendly manner.

  1. Hydrocarbons, for example propane, R290 or propene, R1270 and low-fluorinated flammable refrigerants, for example R1234yf, dissolve very well in refrigeration compressor oil at room temperature. This also applies to blends containing these substances.
  2. Used oil from such systems may still contain relatively high percentages of dissolved flammable gases even at atmospheric pressure. These components gas out.
  3. Observe during storage and transport:
  1. Fill used oil into pressure resistant vessels.
  2. Fill vessels with nitrogen as a protective gas and close them.
  3. Mark them, e. g. with the warning sign "flammable substance" W021 from ISO7010.

Elastomer compatibility

Relevant literature recommends the following seaI materials for polyolester oils (POE) with HFC and HFO refrigerants: