R22 vs R407c

[icecube51]

Hi all,

have spoken to a brand engeneer today about larger units that are working on R22,and change them to R407C. what are the benifits,whats to look out for and so on. he told me they have a few units in the range of 100 to 300Kw cooling capacity that they have changed to R407c,changed the TEV,filter-dryers,the oil a few times,some joints,and so far so good for about 2years now.
are there engeneers that have done the same,and what where there results and conclusions.

thnx, Ice

[NoNickName]

It looks a sensible advice to me. Been there, done that.

[Entropie]

I have done a couple of liquid chillers (air & water cooled) with good results. The cooling capacity is about 5-7% lower then but the EER stays almost the same. Chilled water outlet temperature should be limited to a minimum of +6°C to avoid freeze ups (check setting of low pressure switch and adjust if neccessary). R407C is critical on glycol applications with chilled liquid leaving temperatures lower then -2°C (most coolers are limited to a minimum temperature of -10°C on the refrigerant side, refer to the cooler nameplate). R407C should not be used on commercial refrigeration (R404A or 507 are better but complete recalculation of the system has to be done). The most important on retrofit is the compressor and gaskets material. Compressor compatibility can be reffered from the manufacturer (Important!). Gasket material compatibility can be found on the suppliers info (valves, sight glasses, driers, etc.). It makes sense to change O-Rings. The POE oil should have generally the same viscosity as the mineral or PAG oil used with R22 (use the compressor manufacturer recommended one). Mineral oil content should be less then 2%, a couple of oil changes might be requiered to achieve this. Otherwise oil fouling in the evaporator can happen. The TEV can be left in the unit due to the very close values of R22 and R407C. Adjustemt of the suction superheat is neccessary. Pipework can remain, flow rates are nearly the same, oil return, etc. as well.

[icecube51]

that was or still is one of my main problem, the oil return,or guidense via tube's and valves. i am not concerned for the compressors. 4x 4 cylinder Carleyles on a total of 560Kw cooling capacity.

Ice

[NorthSeaTech]

All R22 systems here have been converted to R417A (isceon 59) as it does not require any modification or oil change. Never had any problems with it at all.

As for R407 we never use it, just thought i would offer up a view on an alternative.

[Entropie]

All R22 systems here have been converted to R417A (isceon 59) as it does not require any modification or oil change. Never had any problems with it at all.

As for R407 we never use it, just thought i would offer up a view on an alternative.

R417A is not miscible with mineral or PAG oil. This can lead in larger systems or liquid receivers to oil seperation, where the mineral oil floodes on top of the refrigerant level. Then it might be reqiured to add POE oil (up to 30%) to the system to recover the oil, but oil mixtures are not recommended by the oil manufacturers.

[icecube51]

is there anyone who found a way to compensate the capacity loss if the unit was converted whit R407c ??

Ice

[K.R.Iyer]

is there anyone who found a way to compensate the capacity loss if the unit was converted whit R407c ??

Ice

We have learnt to live with 5% capacity loss while retrofitting with 407C - with all the training on refrigerant properties...

Ice, do you have the liberty to touch the system design? If yes, the system design parameters could be improvised (flow rate, evp / cond temp etc.) to compensate the 5% loss.

[icecube51]

hey K.R.Iyer, indeed i have the possibility of the layout, and was thinking about that way already, but 2 donkey's are smarter than 1 see, so all advice is welcome,better to have 10 possibility's than 1.

thnx M8, Ice