Replacing R-22 with minimal capacity loss

First, let me introduce myself so you all have a better idea of where I'm coming from.

My name's Marcus. I'm a student at a university on Boston and am majoring in mechanical engineering, although that's looking like an increasingly poor choice as the math courses pile up. My interests are largely in transportation, so refrigeration and HVAC aren't topics with which I'm particularly well-versed.

That said, what I'm trying to figure out is how to replace R-22 in a heat pump system without losing a tremendous amount of capacity. Most of the literature I've seen comes from refrigerant manufacturers, all of whom claim that their refrigerant (R-422b, R-422d, R-407c, etc.) is the best replacement choice given the upcoming R-22 phaseout.

I need to know this because I'd like to be able to reduce the total number of changes to a heat pump designed for R-22. I'm not sure how easy it is to add capacity to a system, but it's bound to be easier if the new refrigerant is as similar to R-22 as possible.

Any ideas?

Thanks.

No need to replace R22. Just make sure the system is leak proof and leave it run until 2015.

Quote:

---

Originally Posted by NoNickName

No need to replace R22. Just make sure the system is leak proof and leave it run until 2015.

---

The problem with that is that this system won't be installed until after the R22 phase out, so it'll need to be reinstalled. Funny how grant money works.

Hi HuntingdonHuskey,

Currently there is nothing on the market that can replace R22 as a 'drop in' or 'retrofit gas' that can service the same temperature range or exhibit the same capacity.

Current retrofit gases include the Isceon 9 series manufactured by DuPont and the RS range manufactured by Refrigerant Solutions. All will do a job and run at 'comparible' pressures with no oil change but will not be as good as R22; three factors cause this:

1) they do not have a latent heat as high as R22,
2) the saturation curve for these products is on a slight 'lean' meaning that more flash gas comes through the expansion valve than with R22 at the same conditions
3) the loss of capacity 1+2 cause is counteracted slightly by the fact these gases have a higher vapour density than R22 meaning the compressor can move more mass with each stroke.

You can limit the capacity loss by cracking open your expansion valve to significantly increase mass flow in the system but you will not be able to get the same capacity as R22

Isceon 99 - R438A may be your best bet as it is designed for fixed orifice water chillers and has probably the best capacity of the lot

hope this helps

best of luck

R422D
is also used to replace R22. not sure how it would run with a heat pump system. R422D is a close match to 22 in terms of capacity and efficiency.

In Italy my we are using R417 (isceon family from Dupont)to retrofit something like a thousand units from a nationwide company.We have seen a massive improvement but it's due to the poor maintenance of the units for the last three years!can you belive all the units were short charged and the tx-valve open full blast all because the previous technicians(undeserved title)didn't know how to set a condensing pressure switch!!!!all units were condensing minimum at 19-20 bars!to avoid hp alarms in the hot months they discharged refrigerant,to avoid lp they opened the t-valves!Anyway,R417 is now happily cooling many data centres,a simple drop in without change of oil.