View Full Version : More R-417A Questions

04-08-2005, 09:36 PM
I'm looking through various alternatives to R-22, for use in already designed systems. We would strongly prefer a refrigerant that does not require hydroscopic oils, since we have had trouble with customers in the past mishandling their systems ("don't mess with the settings" just doesn't seem to work sometimes).

One item that is mentioned as a potential replacement for air conditioning only (not for use in colder evaporator systems or certain other situations) is R-417A / NU-22 / Isceon 59.

It looks like R-417A is being used by some OEMs in the USA already:

I'ver read some of the propaganda from Rhodia ( http://www.isceon-refrigerants.co.uk ) and ICORs literature (http://www.icorinternational.com/literature.html). I've also read all the anti-R-417A stuff that DuPont refrigerants has put out, yet I also see that DuPont has recently purchased R-417A production capacity from Rhodia, so perhaps that propaganda will change soon.

There is a lot of conversion information available from these two manufacturers, and how to tune a system for this particular blend. However, I am particularly interested if anyone out there has dealt with redesign of an R-22 system to use this refrigerant.

Oh, and before you suggest R-410a instead, we have looked at that, and the critical point is awfully low. From time to time our systems wind up in places where condenser air can be 120-130 deg. F, and 410a has a critical point such that a severe redesign of the entire system would be necessary. Also, as our customers typically already have some of our R-22 systems in place, we would like to design a system so that they don't have to carry two sets of refrigerant gauges, etc. to deal with two different pressure ranges - R-22 and R-410a.

Since an R-417a system could probably be designed around the same condensers, compressors, and evaporators, and possibly use the same oil (we would likely use AB oil as apparently there can still be oil circulation issues on some systems with mineral oil and this refrigerant), it looks like it has a lot of possibilities.

However, I would like to know what the real experience is.

04-08-2005, 09:56 PM
Hi Glabah

R417a shouldn't need any major changes to the system as it will work with mineral or POE oil.
Its characteristics are quite similar to R22 so the exsisting tevs should just require a minor tweak.If I recall correctly charge weight required to replace R22 is the same charge.
Condenser and evaporator coils should be ok without modification.

Having said all that the only way to be certain that it will suit your requirements is to try it.


05-08-2005, 11:12 PM
Thanks. The more I've read the more it sounds like our best option, vs. having to deal with POE oils or redesign around R-410or other high pressure system.

Daz B
06-10-2005, 09:25 PM
I have experience of retrofitting R59. i tried it on a number of chillers from 11kW to 75 kW input power. Things to look out for, slightly reduced amount of refrigerant for charging. Reduced capacity of chiller unit by about 10%. Increase in efficiency slightly. You may need to change superheat settings.

All in all I bearing in mind that I started this about 4 / 5years ago, I have chillers still running on the original charge and still performing well!.

Also look out for R29 which has been designed slightly differently for water chillers.

NB. I only tried the retrofit on recipricating units, not screws?

07-10-2005, 05:52 AM
liebert hiross have been using R417a now for a while as a replacement for R22 in their older range of close control units i hear it works well for these type applications but no so good for low temp systems

07-10-2005, 02:58 PM
About Five years ago I was involved in retrofitting some Hitachi screw chillers from R22 to R59. When we ran the chillers the R59 gave us a very low discharge superheat. As the Hitachi screw requires a higher discharge superheat (30) we put the chiller back to R22. The same thing happened when we retrofitted an old Hitachi VRF system. R59 seems to work okay on small splits, but not screw chillers and VRF