Polynomial refrigerants

[Peter_1]

Does someone know what the polynomial is or where to find on the web for R134a and R404a?
This is to draw a complete refrigerant log/P chart like Coolpack is doing.
Thanks

[US Iceman]

Hi Peter.

Are you looking for the equations to generate the refrigerant properties?

Or,

Are you wanting to draw the Mollier diagrams yourself?

[Peter_1]

It is to draw the complete Mollier Diagram.

Purpose: a VFD controlled compressor with a real-life cycle, not those you always see in the books like in the attached figure.

Different gasses can be filled, EEV, crankcase pressure regulator, evaporating pressure regulator, condenser pressure regulator, PHE to increase SC, even a PHE to increase SH so that the effect can demonstrated of a non isolated liquid line, a too small suction line, discharge line, .....

Hot gas defrost running in an AC application and a freezer application.

Sight glasses too see when flash gas forms.

All the necessary parameters will be captured by +/- 7 pressure transducers and 7 temperature sensors and drawn in real-time on a Mollier diagram on a PC and projected via a beamer.

So, for each point, I need a pressure and a temperature sensor.
I only have a problem to demonstrate pressure increase due to a vessel which is installed on a higher level than the EEV. I don't see how I can do this. Only a pressure increase is possible.

You then can see in real-time what happens when parameters change like in a real-life situation.
It's sometimes difficult to make the link of a theoretical cycle to a real life cycle.

COP is constantly calculated, P drawn, I drawn,
This is for an offer we have to make and it's not sure we will have to make it.
But it is for me a nice project.

BTW, line 2/3 and 4/5 is drawn vertically by Coolpack, which isn't correct in my opinion. This must be drawn along an isotherm or at least with an angle to the right for line 2/3 if heating is added along the suction line.

[US Iceman]

This must be for your classroom students?

I thought about this a long time ago, and to be honest, I thought it would take too much time to get all of this work properly.

You need the data acquisition sensors (pressures & temperatures) to feed into a program of some type. It might be possible to take a drawing of a PH diagram and scan it into an electronic file. Then scale the drawing so that the individual points of the refrigerant sensors are plotted on the drawing by a graphics package.

If CoolPack had the ability to accept inputs from the data sensors your project would almost be done.

[Peter_1]

One of the professors at the Danish University has done exactly the same with Labview (Scada software package)
I send him a mail if he want to sell this.
I got another mail of the University "You can download a DLL package called RefEqns, with all the refrigerant equations used to draw the log(p)-h diagrams at: http://www.et.web.mek.dtu.dk/WinDali/Index.html"
Hopes this can help others