View Full Version : Refrigerant phormula

14-03-2005, 08:39 PM
For some perhaps a stupid question, but where can I find - if it excists- a phormula to calculate pressures via temperature and temperature via pressure for saturated conditions?

Purpose: to implement in a PLC program to calculate superheat and subcooling.
Adding a lookup table is also possible of course but it would look more professional if we can use a phormula.

14-03-2005, 11:05 PM

Have a look at http://www.lonmark.org/profiles/10011_10.PDF and check on page 12 of 13.

Hopefully it is not copywright, but as it's a calculation I wouldn't think so and I hope it helps.

15-03-2005, 10:06 AM

I?m sure the algorithms exist, but whether they are freely available I do not know.
I suspect that they are proprietary.

Have a look at this link to Solvay?s site, it?s in English, (but they offer other languages, if you prefer).

There are some downloadable packages available here. They also have a CD ROM that they give away that has a number of calculation options for all the common refrigerants.

I suspect that you may encounter problems with predicting superheated conditions in high-glide Zeotropes because the fractions are never pure.

Of course, you may already know this, but I hope it helps.
vaporizer wiki (http://vaporizerwiki.com)

15-03-2005, 06:34 PM
Peter, contact or check on line the refrigerant manufacturers. I know they use to have the equations of state published for the various refrigerants. I had a boklet from ASHRAE at one time that listed the equations.

With all of the new blends (400 series), I have trouble getting all of the imformation that was available on the old stable of refrigerants.


16-03-2005, 05:59 AM
Well, we need R404a and R134a and R507, if possible.

27-03-2005, 05:17 PM
ASHRAE publishes a booklet with all of the Equations of State for the refrigerants. Anyway they did before we got hit with all of the blended refrigerants. Might check the ASHRAE site fro the info under publications.


29-10-2005, 03:37 PM
wow you guys rock. I have absolutely no idea what all that means but wow.

Oh yeah I'm a 1st yr RAC apprentice and am considering an engineering diploma. I hope this site is here forever.:)

CECOMEF site might help???:)