thermal differences between mineral and polyester oils

[antonio nunes]

Hi..any good hints/indications or links on the matters of how those two oils behave towards temperature?...to be more specific the case is a retrofit/refit of an older Stal S71, that´s is supposed to run on R-134a from now on...(previously R-22)
----I wonder if the isentropic efficiency will get better( less heat waste from compressor) since the new oil will have better cooling properties.
..but assumptions will not do the trick, so any help in form of reliable info will most welcome. Best regards AA

[TXiceman]

Best place to get the thermal data the oils is from the oil manufacturer. The oils do have slightly different specific heats and therfore will be slightly different in heat capacity and heat transfer ability. The difference is so slight that the oil will have little bearing on the compressor performance...but there will be a little.

Ken

[Josip]

Hi, antonio nunes :)


Hi..any good hints/indications or links on the matters of how those two oils behave towards temperature?...to be more specific the case is a retrofit/refit of an older Stal S71, that´s is supposed to run on R-134a from now on...(previously R-22)
----I wonder if the isentropic efficiency will get better( less heat waste from compressor) since the new oil will have better cooling properties.
..but assumptions will not do the trick, so any help in form of reliable info will most welcome. Best regards AA

the most important is your oil cooler .... and this valve, see attachment ...

further on, your system is full of old oil which maybe is not compatible with new oil but still OK i.e. compatible with R134a ... you have a big job to make your system clean of old oil .... my suggestion is to use any oil compatible with the new refrigerant and with the old oil within system .... that is the best you can do for your plant ...

Polyester oil are better, but for me there is not a good value for price ... this is my opinion.

In my car I am using very expensive and good oil according to car manufacturer but I change it (oil filter too) every 10000 km instead of 20000 recommended by manufacturer;)

6565

hope this is of some help to you...

Best regards, Josip :)