glabah
27-02-2006, 07:15 PM
We've been using Colmac Coil's software for doing coil capacity estimates for system design. However, now we have a specification for designing a system using R-407C, a refrigerant that their coil software doesn't have available in its options.:mad:
I know compressor capacity decreases a little bit with the change from R-22 to R-407C - at least the compressor manufacturers are up to date.:)
Since I was unable to run a set of calculations for a coil for R-407C using the Colmac software, I decided to use Super Radiator Coil's software instead. Their software is a little less user friendly and also I don't have a lot of experience using it. However, when I put in R-22 numbers, and used the exact same numbers for R-407C, their software showed a slight increase in capacity for R-407C over R-22.:confused:
Obviously there is an issue with high temperature ambient conditions because R-407C has a critical point about 86 deg C, whereas R-22 has a critical point about 100 deg. C. Therefore, there will obviously be a decrease in condenser capacity in R-407C at high outside temperatures.
However, for normal air conditioning temperatures, say evaporator temperatures in the 5 deg C range and the ambient at the condenser at most about 45 deg. C, do the coils generally show an increase in capacity when going from R-22 to R-407C? I can see this happening due to the nature of the temperature glide in the coils, but my impression has been that if a unit is converted from R-22 to R-407C, generally there is a 5% to 7% decrease in capacity. Is this decrease in capacity based entirely on the decrease that comes at the compressor?
I know compressor capacity decreases a little bit with the change from R-22 to R-407C - at least the compressor manufacturers are up to date.:)
Since I was unable to run a set of calculations for a coil for R-407C using the Colmac software, I decided to use Super Radiator Coil's software instead. Their software is a little less user friendly and also I don't have a lot of experience using it. However, when I put in R-22 numbers, and used the exact same numbers for R-407C, their software showed a slight increase in capacity for R-407C over R-22.:confused:
Obviously there is an issue with high temperature ambient conditions because R-407C has a critical point about 86 deg C, whereas R-22 has a critical point about 100 deg. C. Therefore, there will obviously be a decrease in condenser capacity in R-407C at high outside temperatures.
However, for normal air conditioning temperatures, say evaporator temperatures in the 5 deg C range and the ambient at the condenser at most about 45 deg. C, do the coils generally show an increase in capacity when going from R-22 to R-407C? I can see this happening due to the nature of the temperature glide in the coils, but my impression has been that if a unit is converted from R-22 to R-407C, generally there is a 5% to 7% decrease in capacity. Is this decrease in capacity based entirely on the decrease that comes at the compressor?