In Use Of The New Refrigerant R407C - Fujitsu AB12 Service Manual

9. IN USE OF THE NEW REFRIGERANT R407C

9-1 What is CFC/HCFC/HFC ?
H
(HC : Methane)
CFC : Chloro-Fluoro-Carbon
= high ODP(ozone depletion potential) chemical compound containing chlorine (ODP: 0.6 - 1.0)
HCFC : Hydro-Chloro-Fluoro-Carbon (R22)
= Iow ODP chemical compound containing chlorine and hydrogen (ODP:1/10 - 1150 of CFC)
HFC : Hydro-Fluoro-Carbon (R407C)
= zero ODP new chemical compound in which is not containing chlorine (ODP: 0)
9-2 Characteristics of R22 and R407C
HANDLING
As in the case of R22, the specific gravity of its vapor
is larger than that of air and should it leak in an air-
tight room it may stay at a low level and cause oxy-
gen starvation accident.
cause a poisonous gas to occur, so be sure to handle
it only in a well ventilated area.
SELECTION OF REFRIGERANT
As there is no appropriate mono-constituent refriger-
ant to replace R22 which has been used for conven-
tional air conditioners, the mixed refrigerant of HFC
series was developed.
R407C
Merits
As working pressure is nearly equal to R22 (about
1.1 times), pressure resistance design is easy.
–– Discharge compressor
Max. 30.0 bar for reciprocating compressor
Max. 28.5 bar for rotary compressor
Demerits
Composition control is necessary for charging refrig-
erant as it is zeotropic refrigerant.
–– When leaked, it will become composition of more
R134a constituent with high boiling point.
Also, charging refrigerant must be done from the liquid
phase side.
Review of control system is required as there is temper-
ature glide.
R407C is used for large air conditioners.
Pressure resistance design is easy and safe.
H
C
H
H
F F
C CI C CI
F F
H
CI
(CFC-12) (HCFC-22)
Composition
Boiling point
Ozone depletion
potential ODP
Global warming
potential GWP
Inflammability
Toxicity
Azeotropic or
Zeotropic
Features
– 129 –
F
C
F H
H
(HFC-407C)
R22
R22 R32/R125/R134a
(wt%)
(100)
-40.8
0.055
1,700
Nonflammable Nonflammable
(A1)
less
–––––––
Necessary to handle
carefully because of
zeotropic. Working
–––––––
pressure is nearly
equal to that of R22
(about I .1 times).
R407C
(23/25/52)
-43.6
0
1,530
(A1/A1)
less
Zeotropic