Instructions
18 | AN405821998738en-000102 - 118A5495A
© Danfoss | Climate Solutions | 2023.02 | LCA012A024
(3).2 Refrigerant quantity for connected show case or unit cooler
Check the total capacity (ℓ) of show cases and unit coolers to be connected. Calculate the charge quantity by multiplying the refrigerant charge rate.
Refrigerant of show cases or unit coolers to be connected = Total capacity of show cases or unit coolers to be connected (ℓ) x Refrigerant
charge rate
* Refrigerant charge rate of show cases or unit coolers: 0.2 (kg/ℓ)
(3).3 Piping refrigerant quantity
Piping refrigerant charge quantity is calculated from the specifications of liquid pipe of connecting pipe (pipe size) and the length of each pipe.
Piping refrigerant charge quantity (kg) = Additional charge quantity/m of Ø6.35 (kg/m)Ø x L1 + Additional charge quantity/m of Ø9.52 (kg/m)
x L2 + Additional charge quantity/m of Ø12.7 (kg/m) x L3 + Additional charge quantity/m of Ø15.88
(kg/m) x L4 + Additional charge quantity/m of Ø19.05 (kg/m) x L5
L1: Total length of Ø6.35 (m), L2: Total length of Ø9.52 (m), L3: Total length of Ø12.7 (m), L4: Total length of Ø15.88 (m), L5: Total length of
Ø19.05 (m)
4. Maximum refrigerant charge quantity
Confirm that the refrigerant charge quantity as calculated in the step (3) is not larger than the maximum refrigerant charge quantity.
Get the maximum refrigerant charge quantity from the Ø12.7 equivalent pipe length using the Fig. 20. and calculate the Ø12.7 equivalent pipe length of
Fig. 20 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)
When Refrigerant charge quantity calculated in the step (3) < Maximum refrigerant quantity, charge the refrigerant in the quantity calculated in the step (3).
When Refrigerant charge quantity calculated in the step (3) ≥ Maximum refrigerant charge quantity, charge the refrigerant in the maximum refrigerant
charge quantity.
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)
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. 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
Fig. 20
Fig. 21