3-2.Refrigerant Charging Calculation - Mitsubishi Electric PUHY-RP-Y(S)JM-B Data Book

3. Piping Design
3-2. Refrigerant charging calculation
Sample connection (with BC controller and 4 indoor units)
OU
H H'
Reducer (P15~P50)
(attached with BC controller)
h1
Amount of additional refrigerant to be charged
Refrigerant for extended pipes (field piping) is not factory-charged to the outdoor unit. Add an appropriate amount of refrigerant for each pipes on site.
Record the size of each high pressure pipe and liquid pipe, and the amout of refrigerant that was charged on the outdoor unit for future reference.
Calculating the amount of additional refrigerant to be charged
The amount of refrigerant to be charged is calculated with the size of the on-site-installed hige pressure pipes and liquid pipes, and their length.
Calculate the amount of refrigerant to be charged according to the formula below.
Round up the calculation result to the nearest 0.1kg. (i.e., 16.08 kg = 16.1 kg)
<Amount of additional refrigerant to be charged>
Calculating the amount of additional refrigerant to be charged
High pressure
Additional refrigerant pipe size
charge Total length of ø 19.05
=
x 0.16
(kg) (m) x 0.16(kg/m)
Total outdoor unit
Model
+
RP200
RP250
RP300
Amount of factory charged refrigerant
Outdoor unit
Charged amount
Model
RP200
RP250 11.8 kg
RP300
A
For outodoor units equal to or larger than a size P400, on
the BC controller please ensure CMB-P
BC controller
Joint
a
b
(CMY-R160-J1)
IU IU
(P15-P80) (P100-250)
High pressure
Liquid pipe size
pipe size
Total length of ø 12.7
Total length of ø 15.88
+ +
x 0.11
(m) x 0.11(kg/m)
Charged amount per
BC controller
BC controller Charged amount
(Sub) Total units
(Standard / Main)
+
2.0 kg 1 unit
2 units
3.0 kg
Sample calculation
A : ø28.58 40m
B : ø9.52 10m
Total length for each pipe size :
Therefore, additional refrigerant charge
SYSTEM DESIGN
V-GA1 is used.
•
IU
Joint
d
B
c
IU
Max.3 sets for 1 port.
Total capacity <= P80
Liquid pipe size
Total length of ø 9.52
+
x 0.12 x 0.06
(m) x 0.12(kg/m) (m) x 0.06(kg/m)
Total capacity
of connected Charged amount
+ indoor units
1.0 kg -80 2.0 kg
2.0 kg 81 - 160 2.5 kg
161 - 330 3.0 kg
331 - 390 3.5 kg
391 - 450 4.5 kg
Indoor
1 : P80 a : ø9.52 5m
2 : P125 b : ø12.7 3m
3 : P15 c : ø6.35 2m
4 : P20 d : ø6.35 3m
ø15.88 A = 40m
ø12.70 b = 3m
ø9.52 B + a = 10 + 5 = 15 m
ø6.35 c + d = 2 + 3 = 5 m
= 0.11 x 40 + 0.12 x 3 + 0.06 x 15 + 0.024 x 5 + 2 + 3
= 10.78 kg
= 10.8 kg
h2
Liquid pipe size
Total length of ø 6.35
+
x 0.024
(m) x 0.024(kg/m)
275