R407C Questions

[marwanm]

Hi,

AMAZING FORUM!
I'm new to this forum and actually new to this industry. I just graduated from college, and started a new job and being in expert in Refrigerants is my first task. I am interested in refrigerants for A/C systems in rail cars.

I have some questions with respect to R407C that I hope you can help me with:

1- Assuming the unit (Condenser) is designed for R-22, how big a problem is the glide of the blend? I understand efficiency and performance lower down. by how much? any other differences?

2- Since leakage can be a problem in the mobile environment, fractionation of this blend could be a concern. How would the maintenance department know that fractionation has occurred and when to replace the charge

3- If a fractionated R407C charge is recovered and not severely contaminated, can the refrigerant manufacturer reclaim it, restoring its original composition?

Also, are there any new R22 replacement refrigerants on the horizon that are either near-azeotropes or azeotropes?

Any help is GREATLY appreciated!

Thanks a lot guys! and keep up the good work!

Marwan

[powell]

marwanm,

To start, here is the link to Copelands view on converting from R22 to R407C. There is some good information here.

http://www.hvacrinfo.com/cope_ae_bulletins/95-14.PDF

Here is Duponts link to R407C

http://refrigerants.dupont.com/Suva/.../suva407c.html

Powell

[Brian_UK]

Have a look at Isceon 59...

http://www.eurocooling.com/articlerhodia.htm

[the mojo]

Isceon M029 looks to be worth while.

[Brian_UK]

Isceon M029 looks to be worth while.

Sorry, I thought that I had the right number

[the mojo]

Sorry, I thought that I had the right number

No problem Brian.

Could you put up the html for marwanm, don't have enough required posts yet.

[marwanm]

Thank you guys for your help! I am assuming that Isceon M029 is the R-422D. Who manufactures Isceon?

I will read the articles you gave me and I am sure I will still have few questions.

Again, I really appreciate your help...

M.

[praveen]

K Need To Check The Acidic Effect Too

[Thermatech]

For a/c engineers in Europe R407c was a nightmare dead end trip.
R407c really is a complete waist of time.
Looking back it would have been much better to have delayed R22 phase out to allow manufacturers to develop R410a equipment.
Then we could have moved straight from R22 onto R410a.

If you really want to learn about how to design an a/c system using R407c then I suggest you look at the old R407c Mitsubishi Electric City Multi VRF systems which had a refrigerant blend sensing CS circuit which allowed the outdoor unit to constantly estimate the ratio of R32 in the blend.
Based in this data the system could trim its operation to suit. For instance it could blast some hot gas into the accumulator to stur up the liquid to reduce the fractionation which tends to happen at the accumulator. Lots of split systems & VRF systems had high pressure fault problems which the manufacturers did not want to talk about beacuse of this issue.
At low compressor speed the accumulator get full of R134a & the compressor pumps R32 & R125 arround the system & trips on high pressure.