Refrigerant type for Glycol chiller

[Paul Philippon]

Friends,

We're running R-22 in our glycol chiller, with a chilled water set-point of 31F. That doesn't really allow us to crash tanks as cold as I'd like (though that should improve when we get our new cool-fit system installed!). I suggested to our refrigeration technician that we might do well to drop the set point to 28F. He said that that would be pushing the limits for R-22. So, my question for the board is: what type of refrigerant are others using (or do others recommend) to achieve the crash temperatures we like to see? Thanks for your help!

Cheers,

Paul Philippon
The Duck-Rabbit Brewery
Farmville NC

[gitchegumee]

R-22 is being phased out. We use R404A now. Sometimes you can simply change out the freon and oil with a good cleaning, but often you cannot and must buy a new compressor. You'll have to listen to your qualified refrigeration professional.

[jimvgjr]

I don't think it's a question of R22, but likely if the system is designed to operate at these lower temperatures.

All of the systems we manufactured prior to 2009 were supplied with R22, with some operating at glycol temperatures as low as 15 F.

The issue could be due to the rating on the refrigeration compressor. If it is a compressor designed for Air Conditioning, it's possible the technician is concerned with operating outsides it's operating envelope- and these are valid as I've seen many systems experience multiple failures simply because the system was operating at a much lower evaporator temperature than it was designed.

I wish it was simple as changing the refrigerant, I'd clarify this with your contractor or contact me Paul and we can confirm the operating envelope on your system.

Good luck,

Jim

Pro Refrigeration Inc.

[jimvgjr]

In regards to R22 being phased out, Phil is exactly right.

Although we are no longer producing new R22 systems (all manufacturers were prohibited from producing R22 systems 2010), the refrigerant is still being produced and available for service and existing equipment. R22 will be completely phased out in 2020.

Many systems can be converted from R22 to R404A, however it generally involves more than a swap of the refrigerant (oil, filters, expansion valves, and possibly compressor change too). If the compressor isn't rated for operating at lower temperatures with R22, it will likely carry over with R404A.

I often advise people not to convert over unless they have lost a compressor and will be upgrading or making an investment in their system already.

Hope this helps,

Jim

[Starcat]

About R-22

The real issue with R-22 relates to a factor called compression ratio, and it mostly only comes into play when attempting to do
" low temp " duty with that gas which involves evaporator temperatures of -20F. High compression ratio causes extereme operating temps on the discharge side of the compressor and are dealt with in less than perfect ways, but we are not really talking about low temp duty in this case.
Running setpoint from 31 to 27F should not be that big of a deal on an R-22 chiller designed for glycol service. Freeze protection point of solution should be adequate beyond running range.
Pumping effeciency of glycol goes down with drop in temp, only an issue if anything is marginal. I have experience with chiller plants to 3000 tons of capacity.

HVACR & Industrial Engineering Tech

StarCat

[BrewinLou]

I run our (Prorefer chiller) at 28 in the summer and 30 in the winter. All you have to watch out for is making sure your glycol is mixed down to a freeze point around 12-15 degrees.

Hey Paul, how many tanks (and size) are you chilling with how many horse chiller?