View Full Version : New person says hi and is looking for a p/h chart for R-12

07-01-2006, 03:33 PM
I am new here
I am not use to the site yet and I was searching for a "pressure/ enthalpy chart for refrigerant 12
I found the heading in the site which I have listed below, but I was unable to open it.

Links and Downloads Database
Pressure-Enthalpy Chart

My request is if any body can lead me to a P/h chart for refrigerant 12
My instructor gave us one which is barely readable so I got one from the net BUT, the
KJ/Kg is way off base.
I do not understand and my instructor can not say why.

I am in 3rd year marine engineering and doing air conditioning in my 3rd thermodynamics.
The chart which is barely legible, that our instructor handed out, works with our calculations from the text book (Basic Engineering Thermodynamics by Rayner Joel) so we will be using it to prepare for our 1st class Marine Engineering test after graduation.

I would like to find a chart that I can see clearly and that has the proper enthalpy scale.
Thank you in advance

I hope to add to the forum on a regular basis.

07-01-2006, 04:54 PM
Hi frankiee

Please don't double post in differnt areas of the forum

Erik Detroit
07-01-2006, 05:39 PM
Hi Frankiee,

The Enthalpy scale of a p-h digram varies because there is not a universally agreed upon reference point for zero enthalpy. In fact tha same is true for entropy.

These two values are always used in calculations that involve the difference between two states, so the reference point doesn't make a difference to the correctness of calculations. For example to calculate the power a compressor uses if the mass flow rate and the suction (P,T) and the discharge (P,T) are known you use P=m_dot*(h_discharge-h_suction). Since this is only a difference between two values of enthalpy, their absolute values do not matter, only the difference between the two has to be correct.

Back to the point....tell me what you would like to use as a reference point, and I'll post a chart for you. Common ones are:

ASHRAE (US): h=0 @ -40C, s=0 @ -40C
IIR: h=200 kJ/kg @0C, s=1 kJ/kgK (for sat liquid) @ 0C

or give me some other reference points

Cheers and good luck,

07-01-2006, 09:33 PM
I would like a chart where the critical point is at 180 KJ/KG if I could get one.
Thank you for your reply and help

07-01-2006, 09:45 PM
Enthalpy & entropy. Hmm..I empathise emphatically...:D

07-01-2006, 11:14 PM

Allways nice greeting new and...polite members.
Download once Coolpack from the Danish University. It's free and very powerfull.

08-01-2006, 10:43 AM
Check out- http://www.dupont.com/suva/emea/products/technical/molier_pe.html




Puron is Carrier's trade name for R410a. There are quite a few contraversies over whether or not R410a is any better then R22 but the fact is that R22 is being fazed out and more and more high end equipment with better features are being developed using R410a.

If you don't require super high efficiency or two stage cooling, you are just as well to consider the R22 systems. There are still a few years left before R22 will become obsolete and even then parts and refrigerant will be available for it.

08-01-2006, 11:29 AM
try this

Erik Detroit
08-01-2006, 05:36 PM
I'm printing this from the DTU software. Peter is right you should just learn to fish and download this program. I'll post anyway because I said I would.

The limit is 100k, so this picture is not very good compared to printing out of the DTU Refrigeration Utilities program.


08-01-2006, 06:31 PM
I am new here
I am not use to the site yet and I was searching for a "pressure/ enthalpy chart for refrigerant 12

Hopefully you now have plenty of leads about R12 Mollier charts and transport data from other posters, but I'm puzzled why, in this day and age, your tutor is using R12 as an example?

As a CFC, it is banned in use in all but developing countries. Hence the problems you are encountering in finding details about it.

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09-01-2006, 01:07 PM
Production of R12 or CFC-12 was halted by the clean air act on January 1, 1996. Today the remaining supplies are product which has been recovered and reclaimed back to a chemically pure state in accordance with ARI-700 standards. The ARI standard is basically a virgin specification. The supply of virgin product is limited as most of the virgin was depleted in the first and second years after production ceased.

It seems that almost any evaporatable substance has a refrigerant number... a listing for R-718, better known as WATER!

Here are some prices


09-01-2006, 11:35 PM
Thank you every one.

20-01-2006, 01:26 PM
www.forane.com is a very good site. gus at arkema has been very abliging. Very nice people.