Table of Contents
Advertisement
0 0 0 0 0 DIFFERENCES BETWEEN THE PREVIOUS REFRIGERANT AND THE NEW RE-
FRIGERANT
[1] Chemical Characteristics
The new refrigerant (R407C) is a chemically stable non-combustible refrigerant with few of the same characteristics
as R22.
However, the vapor specific gravity is heavier than the specific gravity of air, so if the refrigerant leaks out in a
closed room, it remains on the bottom near the floor and there is danger of accidents occurring due to lack of
oxygen, so always handle it in an atmosphere with good ventilation where the refrigerant won't accumulate.
Composition (wt%)
Refrigerant handling
Chlorine
Safety class
Molecular weight
Boiling point (°C)
Vapor pressure (25°C, MPa) (Gauge)
Saturated vapor density (25°C, kg/m
Combustibility
Ozone depletion coefficient (ODP) 1
Global warming coefficient (GWP) 2
Refrigerant charging method
Additional charge when leaking
[2] Chances in Composition
R407C is a nonazetropic refrigerant composed of 3 components, R32, R125 and R134a. Therefore, if refrigerant
leaks from the gas phase unit, that containing large amounts of the R32 and R125 components will leak out, so
there will be more R134a remaining in the machine, and there is a possibility that breakdown of the machine due to
insufficient capacity (condensation on the heat exchanger, etc.) could result. Also, if the equipment is charged with
refrigerant directly from a bombe, if it is charged in the gas phase, the composition will change greatly, so be sure
to charge the equipment from the bombe's liquid phase side.
1 Nonazetropic refrigerant
In both gas phases, when charging refrigerant from a bombe with refrigerants which have different compositions,
the composition will change if refrigerant leaks from the unit. As an example, the change in the composition of
the refrigerant is shown in the case where R407C is charged as a gas from a bombe, and in the case where it is
charged as a liquid. Compared to when the refrigerant is charged as a liquid, the change in composition is great
and the influence on unit performance and operating state is great, so it is necessary to charge the refrigerant in
the liquid phase.
Change in Composition when Charging in the Liquid Phase
Bombe Internal Capacity:1m
23.0
22.5
22.0
21.5
21.0
0.9
(Volume Remaining in Bombe/Bombe Internal Capacity) [kg/ ]
3
)
1: If CFC11 is used as the reference.
(R407C [HFC-32/HFC-125/HFC-134a])
3
, Initial Charge Volume:900kg
0.8
0.7
0.6
0.5
0.4
0.3
0.2
Proportion Remaining in Bombe
New refrigerant (HFC based)
R407C
R32/R125/R134a
(23/25/52)
Nonazetropic refrigerant
Not included
A1/A1
86.2
-43.6
0.9177
42.5
Noncombustible
0
1530
Fluid charging
Impossible
Change in Composition when Charging in the Gas Phase
(R407C [HFC-32/HFC-125/HFC-134a])
Bombe Internal Capacity:1m
35
30
25
20
15
10
5
0
0.1
0.0
0.9
0.8
0.7
Proportion Remaining in Bombe
(Volume Remaining in Bombe/Bombe Internal Capacity) [kg/ ]
–155–
Previous refrigerant (HCFC Based)
R22
R22
(100)
Single refrigerant
Included
A1
86.5
-40.8
0.94
44.4
Noncombustible
0.055
1700
Gas charging
Possible
2: If CO
is used as the reference.
2
3
, Initial Charge Volume:900kg
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0°C
10°C
20°C
30°C
40°C
Advertisement
Table of Contents
