Equation of State for R134a

[bornehatred]

hi everyone,
i need some help on equation of state for refrigerant R134a. I know that there are a few equations regarding to that but i'm only interested in Martin-Hou and Modified Benedict-Webb-Rubin equation.
The problem is, I only have the principal equation of both which is useless since I do not know how to derived them properly to obtain thermodynamic properties of the refrigerants (enthalpy, entropy etc).
I really in need of that equation to finish off my degree here, so please if anyone knew anything about it, post some help here.

[nh3simman]

hi everyone,
i need some help on equation of state for refrigerant R134a. I know that there are a few equations regarding to that but i'm only interested in Martin-Hou and Modified Benedict-Webb-Rubin equation.
The problem is, I only have the principal equation of both which is useless since I do not know how to derived them properly to obtain thermodynamic properties of the refrigerants (enthalpy, entropy etc).
I really in need of that equation to finish off my degree here, so please if anyone knew anything about it, post some help here.

You can download the data sheet of R134a from the DuPont web site. It is a 426K pdf that has the equations, the saturated tables and the p-h diagram.

Gosney chapter 3.18 gives an example of how calculate thermal properties from the equations.

ASHRAE have also published some papers on the subject. I remember the name Downing.

In my opinion, NIST is the most comprehensive source of information on refrigerant properties. The manual can be downloaded from the NIST web site and you will find plenty of detail about the application of equations.
http://www.nist.gov/srd/nist23.htm
Eric Lemmon at NIST is also very helpful.


Hint: When working with these equatons, watch the units. (Ratio of critical and molar units generally used).

[bornehatred]

i tried the solution you suggest me but still my supervisor didnt satisfied with that.she insists on doing it manually,means that i need to do the calculation by myself using those equation of state.i know this might be too much to ask but if you have a copy of this article from ASHRAE transaction entitled "Thermodynamic Properties of a New Stratospherically Safe Working Fluid – Refrigerant 134a" can you mail it to me.I used to have a copy of those but it seems that i misplaced it and can't find it anywhere.

[nh3simman]

Hi bornehatred, Sorry, I do not have the ASHRAE Transactions article that you need. But you can get it directly from ASHRAE.

I can't see why your supervisor would object to the other sources. You don't have to use the NIST program to get the properties. What I suggested is that you look at the manual that you can download. It describes the equation of state and the other thermophysical properties in detail. And if you get stuck, email Eric for help.

[rays17]

You can download the data sheet of R134a from the DuPont web site. It is a 426K pdf that has the equations, the saturated tables and the p-h diagram.

Gosney chapter 3.18 gives an example of how calculate thermal properties from the equations.

ASHRAE have also published some papers on the subject. I remember the name Downing.

In my opinion, NIST is the most comprehensive source of information on refrigerant properties. The manual can be downloaded from the NIST web site and you will find plenty of detail about the application of equations.
http://www.nist.gov/srd/nist23.htm
Eric Lemmon at NIST is also very helpful.


Hint: When working with these equatons, watch the units. (Ratio of critical and molar units generally used).

Hi nh3simman,

I am not sure if my question is still valid since this thread is quite old.
Regarding the Gosney chapter 3.18 that you suggest, could you please give the name in full as I am interested in reading it. Secondly, could you please give the NIST link for the manual to calculate the thermodynamic properties from the equation as the link has dead. Currently I am facing problem in determining the thermodynamic properties for R134a and I am very appreciate for your help and advice.

Thanks a lot

[rays17]

i tried the solution you suggest me but still my supervisor didnt satisfied with that.she insists on doing it manually,means that i need to do the calculation by myself using those equation of state.i know this might be too much to ask but if you have a copy of this article from ASHRAE transaction entitled "Thermodynamic Properties of a New Stratospherically Safe Working Fluid – Refrigerant 134a" can you mail it to me.I used to have a copy of those but it seems that i misplaced it and can't find it anywhere.

Hi bornehatred,

I read your previous thread. Currently, I am trying to calculate thermodynamic properties of R134a using Martin-Hou equation. As you have experienced it before, could you please give me any idea or suggestion for book or manual that can helps me to derive the equation. Your help is much appreciated.

Thanks

[kenbarls]

I found this, but not sure this would help.

http://www.boulder.nist.gov/div838/t...op/REF-MIX.PDF

[rays17]

Hi, Thank you for the link. I manage to calculate the thermodynamic properties of R-134a.