When Refrigerant charge quantity calculated in the step 5.6.3 < Maximum refrigerant quantity, charge the refrigerant in the quantity
calculated in the step 5.6.3.
When Refrigerant charge quantity calculated in the step 5.6.3 ≥ Maximum refrigerant charge quantity, charge the refrigerant in the
maximum refrigerant charge quantity.
In case of the piping system as above, the piping refrigerant charge quantity becomes 6.3 kg from the following calculation.
Piping refrigerant quantity = 0.098 (kg/m) x 10 (m) + 0.054 (kg/m) + (10 (m) + 10 (m)) + 0.025 (kg/m) x (5 (m) + 5 (m)) = 2.3
kg………………… (a)
5.6.5 Example of calculation – Determination of refrigerant charge quantity
Liquid pipe
φ9.52×10m
Liquid pipe
φ6.35×5m
Low pressure
device
Condensing unit
OP-UPAC015COP04E
(Evaporation temperature setting : -10 0C)
Liquid pipe
φ12.7×10m
Liquid pipe
φ6.35×5m
Liquid pipe
φ9.52×10m
Low pressure
device
Low pressure
device
5. System design recommendations
5.6.4 Maximum refrigerant charge quantity
Confirm that the refrigerant charge quantity as calculated in the step 5.6.3 is not larger than the maximum refrigerant charge quantity.
Get the maximum refrigerant charge quantity from the Ø12.7 equivalent pipe length and the Fig. 26. Calculate the Ø12.7 equivalent pipe
length of Fig. 26 with the following equation.
Maximum refrigerant charge quantity is not changed as Evaporation temperature setting.
Ø12.7 equivalent pipe length (m) = Piping refrigerant quantity (kg)/Additional charge quantity/m of Ø12.7 (kg/m)
5
10
15
20
25
30
0
20
40
60
80
100
Maximum refrigerant charge quantity
M
aximum r
efr
iger
an
t char
ge quan
tit
y (kg)
φ12.7 equivalent pipe length (m)
Additional charge quantity/m of refrigerant pipe (Liquid feed pipe)
Refrigerant pipe size x Wall thickness
(For material: C1220 1/2H)
Ø6.35×t0.5
Ø9.52×t0.8
Ø12.7×t1.0
Ø15.88×t1.2
Ø19.05×t1.4
Additional charge quantity (kg/m)
0.025
0.054
0.098
0.155
0.225
Fig. 26
Fig. 27
40
AB408540130380en-000102
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