Oils for refrigerant R290 (propane)
Characterising the oils
Oil | Oil type | Applications | Designation on compressor |
|---|---|---|---|
SHC226E | poly-alpha-olefin oil (PAO) | standard oil charge | "P" (e.g. 4VESP‑10P) |
BSG68K | polyalkylene glycol oil (PAG) | option for compact refrigerating circuits | "Z" |
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
DANGERRisk of explosion and thus danger of death in the event of refrigerant outlet and in the presence of an ignition source!
Refrigerant can ignite and also form an explosive atmosphere depending on its concentration in air!
Avoid open fire and ignition sources in the machinery room and in the hazardous zone!
Owing to the particularly high solubility of refrigerants of safety group A3 (e.g. R290, propane) in customary oils, BITZER compressors are charged with a special oil of a high viscosity index and particularly good tribological characteristics.
In view of the solubility, the design, operating mode and control of the compressor and the system are subject to particular requirements. Low or insufficient superheat in operation and insufficient heating of the oil in the compressor or oil separator during shut-off periods lead to a substantial reduction of the oil viscosity in the compressor. This results in reduced performance, heavy wear on drive gear parts, increased oil carry over and foaming. Secure compressor against ''wet operation'' and ensure sufficiently high suction gas superheat. The discharge gas temperature of reciprocating compressors must be at least 20 K, of compact screw compressors at least 30 K above the condensing temperature in summer and winter operation.
- Low oil temperatures and a high suction side standstill pressure must be avoided. An oil heater is absolutely required and an additional pump down system must be provided if necessary.
- Avoid quick changes in condensing pressure − risk of strong foaming in the compressor or oil separator!
For further information on the use of R290 in semi-hermetic compressors: see Technical Information AT-660
Technical data
BSG68K | SHC226E | Unit | |
|---|---|---|---|
Density at 15°C | 1.003 | 0.830 | g/ml |
Flashpoint | > 200 | 250 | °C |
Pour point | -46 | -45 | °C |
Kinematic viscosity | |||
at 40°C | 68 | 67 | cSt |
at 100°C | 16 | 10 | cSt |
Miscibility gaps
M: Range of complete miscibility.
P: Phase separation range (miscibility gap).
Refrigerant solubility in oil
The following diagrams can be used to read off the refrigerant content in the lubricant depending on refrigerant pressure and oil temperature.
Warning values for used oils
The listed oils SHC226E (PAO) and BSG68K (PAG) are categorized as group KE 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.
Oil | Kinematic viscosity at 40°C (DIN EN ISO3104) | Max. water content | Total acid number |
|---|---|---|---|
SHC226E | outside of 57 .. 76 cSt (*) | 80 mg H2O/kg oil | 0.1 mg KOH/g |
BSG68K | outside of 58 .. 78 cSt (*) | 800 mg H2O/kg oil | 0.2 mg KOH/g |
In case of maintenance, be sure to observe the following:
Danger of spark formation due to unintended switching operations or overheating of the oil heater during oil change.
Prior to interventions in the refrigerant circuit, interrupt the power supply on the main switch!
Observe special regulations for storage and transport of flammable gases.
When performing maintenance work indoors, always switch on room ventilation!
Danger of spark formation, when discharging electrostatic charges!
Take measures against electrostatic charging of non-metallic components, tools, auxiliaries and clothing! For example: Wear suitable antistatic clothing, use spark-free tools. If necessary, perform additional earthing of conducting parts.
Fire hazard!
The used oil contains a relatively large amount of dissolved refrigerant.
Pack used oil safely. Dispose of in an environmentally friendly manner.
- 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.
- Used oil from such systems may still contain relatively high percentages of dissolved flammable gases even at atmospheric pressure. These components gas out.
- Observe during storage and transport:
- Fill used oil into pressure resistant vessels.
- Fill vessels with nitrogen as a protective gas and close them.
- Mark them, e. g. with the warning sign "flammable substance" W021 from ISO7010.
Elastomer compatibility
Relevant literature recommends the following seaI materials for polyalkylene glycol oils (PAG) and poly-alpha-olefin oils (PAO) with R290:
- chlorobutadiene rubber, e.g. neoprenes
- acrylonitrile butadiene rubber, nitrile content >36%
- hydrogenated acrylonitrile butadiene rubber, nitrile content >36%
- fluorinated rubber