Results 1 to 3 of 3
  1. #1
    Join Date
    Jan 2011
    Location
    denmark
    Age
    64
    Posts
    32
    Rep Power
    0

    thermal differences between mineral and polyester oils



    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, thatīs 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



  2. #2
    Join Date
    Mar 2005
    Location
    USA
    Age
    76
    Posts
    639
    Rep Power
    20

    Re: thermal differences between mineral and polyester oils

    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

  3. #3
    Join Date
    Jan 2006
    Location
    Croatia
    Age
    68
    Posts
    2,299
    Rep Power
    31

    Re: thermal differences between mineral and polyester oils

    Hi, antonio nunes

    Quote Originally Posted by antonio nunes View Post
    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, thatīs 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

    Oil temp regulating system.jpg

    hope this is of some help to you...

    Best regards, Josip

    It's impossible to make anything foolproof because fools are so ingenious...

    Don't ever underestimate the power of stupid people when they are in large groups.

    Please, don't teach me how to be stupid....
    No job is as important as to jeopardize the safety of you or those that you work with.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •