Panasonic U-72MF2U9 Technical Data Manual page 35

2. System Design
Example:
Outdoor unit
Type 96 Type 72
A
B
LB
LA
1-1
1
Type 48
Obtain liquid tubing size from Tables 2, 3, 4, 6 and 9.
Main tubing
LA = ø5/8 (in.) (Total capacity of indoor unit is 179,400 BTU/h (52.6kW))
LB = ø1/2 (in.) (Total capacity of indoor unit is 131,600 BTU/h (38.6kW))
LC = ø3/8 (in.) (Total capacity of indoor unit is 83,800 BTU/h (24.6kW))
Distribution joint tubing
Outdoor side A: ø3/8 (in.)
Indoor side 1-1: ø3/8 (in.)
Obtain discharge tubing size from Tables 2, 3 and 11.
Main tubing
LA = ø7/8 (in.) LB = ø7/8 (in.)
Distribution joint tubing
Outdoor side A: ø5/8 (in.)
Indoor side 1: ø5/8 (in.)
Obtain additional charge amount for each tubing size and additional refrigerant charge amount for outdoor unit and all indoor units cooling capacity.
Note 1: The charge amounts per 1 ft. are different for each liquid tubing size.
ø5/8 (in.) LA
ø1/2 (in.) LB
LC +
ø3/8 (in.)
Additional refrigerant charge amount is 418 oz (11,869g).
Note 2: Necessary amount of additional refrigerant charge per outdoor unit is 141oz (4,000g) in combination of 2 units. (See Table 10.)
Note 2) Amount of additional charge for outdoor unit (combination number)
Note 3: Necessary amount of additional refrigerant charge for all indoor unit cooling capacity
[BTU/h]
179,400 BTU/h
Cooling capacity (BTU/h) x 1.034 x 0.001 + 10.6 oz
= 179,400 x 1.034 x 0.001 + 10.6 = 196 oz
Note 4: The charge amounts per 1 ft. are different for each discharge tubing size.
ø7/8 (in.) LA + LB
ø3/4 (in.) B
ø5/8 (in.) LC +
ø1/2 (in.) 1-1 + 2-1 + 3-1 + 4-1
Additional refrigerant charge amount is 92 oz (2,628g).
Note 1) Amount of additional charge per liquid tubing length
Note 2) Amount of additional charge for outdoor unit (combination number)
Note 3) Amount of additional charge for all indoor unit cooling capacity
Note 4) Amount of additional charge per discharge tubing length
Total of additional refrigerant charge amount
Therefore, the total of additional refrigerant charge amount reaches 847 oz (24,057g).
Obtain overall refrigerant charge amount.
Overall refrigerant charge amount of the system indicates the calculated value shown above the additional charge amount in
addition to the total refrigerant charge amount (shown in Table 5) at shipment in total cooling capacity of outdoor unit.
Refrigerant charge amount at shipment
(Total cooling capacity of outdoor unit) :
Total of additional refrigerant charge amount
Therefore, overall refrigerant charge amount of the system reaches 1,433 oz (40,657g).
Remark: Be sure to include the values in Table 10 Necessary Amount of Additional Refrigerant Charge Per Outdoor Unit.
Be sure to check the limit density for the room in which the indoor unit is installed.
CAUTION
Example of each tubing length
Main tubing
LA = 131 ft. (40m) Outdoor side
LB = 16 ft. (4.9m) A = 7 ft. (2.1m)
LC = 16 ft. (4.9m) B = 7 ft. (2.1m)
LC
Solenoid valve kit
2-1 3-1 4-1
2 3 4
Type 48 Type 48
B: ø3/8 (in.) (from outdoor unit connection tubing)
2-1: ø3/8 (in.) 3-1: ø3/8 (in.)
LC = ø5/8 (in.)
B: ø3/4 (in.) (from outdoor unit connection tubing)
2: ø5/8 (in.) 3: ø5/8 (in.)
A + B + 1 + 2 + 3+ 4
: 147 ft. × 0.441 oz/ft. = 65 oz
: 7 ft. × 0.333 oz/ft.
A : 23 ft. × 0.226 oz/ft. = 5 oz
: 157 ft. × 0.129 oz/ft. = 20 oz
Grand total
Distribution joint tubing
Indoor side
1 = 98 ft. (30m)
2 = 16 ft. (4.9m)
3 = 16 ft. (4.9m)
4 = 65 ft. (19.8m)
Type 36
The longest tubing length in this example
(LA = 131 ft. (40m))
4-1: ø3/8 (in.) (from indoor unit connection tubing)
4: ø5/8 (in.) (from solenoid valve kit connection tubing)
: 131 ft. × 1.99 oz/ft. = 261 oz
: 16 ft. × 1.38 oz/ft. = 22 oz
: 225 ft. × 0.602 oz/ft. = 135 oz
Total 418 oz
: 141oz
[kW]
(52.6 kW)
(Cooling capacity (kW) x1000 x 0.1 + 300g
= 52.6 x 1000 x 0.1 + 300 = 5,560 g)
= 2 oz
Total 92 oz
: 418 oz
: 141 oz
: 196 oz
:
: 847 oz
: [168,000BTU/h] 586 oz
: 847 oz
1,433 oz
2 - 19
Design of 3WAY VRF SYSTEM
1-1 = 82 ft. (25m)
2-1 = 13 ft. (4m)
3-1 = 13 ft. (4m)
4-1 = 49 ft. (15m)
(40m × 185 g/m = 7,400g)
(4.9m × 128 g/m =
(68.6m × 56 g/m = 3,842g)
(Total 11,869g)
(4,000g)
(44.9m × 41 g/m = 1,841g)
(2.1m × 31 g/m =
65g)
(7m × 21 g/m = 147g)
(47.9m × 12 g/m =
575g)
(Total 2,628g)
(11,869g)
(4,000g)
(5,560g)
92 oz (2,628g)
(24,057g)
[49.2kW] (16,600g)
(24,057g)
(40,657g)
1
2
3
627g)
4
5
6
7
8
9