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DATA
4
4-1. SELECTION OF COOLING/HEATING UNITS
<Cooling>
Outdoor Design Dry Bulb Temperature
Total Cooling Load
Room1, Room2
Indoor Design Dry Bulb Temperature
Indoor Design Wet Bulb Temperature
Cooling Load
Room3, Room4
Indoor Design Dry Bulb Temperature
Indoor Design Wet Bulb Temperature
Cooling Load
<Other>
Indoor/Outdoor Equivalent Piping Length
Capacity of indoor unit
Model Number for
P•FY Series
indoor unit
Model
Capacity
M Series
Model Number for
indoor unit
Model
Capacity
1. Cooling Calculation
(1) Temporary Selection of Indoor Units
Room1, Room2
PEFY-P50
Room3, Room4
PEFY-P71
(2) Total Indoor Units Capacity
P50 + P50 + P71 + P71 = P242
(3) Selection of Outdoor Unit
The P250 outdoor unit is selected as total indoor units capacity is P242
PUMY-P250YBM
(4) Total Indoor Units Capacity Correction Calculation
Room1, Room2
Indoor Design Wet Bulb Temperature Correction (20ºC)
Room3, Room4
Indoor Design Wet Bulb Temperature Correction (18ºC)
Total Indoor Units Capacity (CTi)
CTi = Σ (Indoor Unit Rating × Indoor Design Temperature Correction)
= 5.6×1.03 + 5.6×1.03 + 8.0×0.94 + 8.0×0.94
= 26.6 kW
(5) Outdoor Unit Correction Calculation
Outdoor Design Dry Bulb Temperature Correction (39ºC)
Piping Length Correction (20 m)
Total Outdoor Unit Capacity (CTo)
CTo = Outdoor Rating × Outdoor Design Temperature Correction × Piping Length Correction
= 28.0 × 0.94 × 0.97
= 25.5 kW
(6) Determination of Maximum System Capacity
Comparison of Capacity between Total Indoor Units Capacity (CTi) and Total Outdoor Unit Capacity (CTo)
CTi = 26.6 > CTo = 25.5, thus, select CTo.
CTx = CTo = 25.5 kW
(7) Comparison with Essential Load
Against the essential load 25.0kW, the maximum system capacity is 25.5 kW: Proper outdoor units have been selected.
(8) Calculation of Maximum Indoor Unit Capacity of Each Room
CTx = CTo, thus, calculate by the calculation below
Room1, 2
Maximum Capacity × Room1, or 2 Capacity after the Temperature Correction/(Room1 to 4 Total Capacity after the Temperature
Correction)
= 25.5 × (5.6 × 1.03)/(5.6 × 1.03 × 2 + 8.0 × 0.94 × 2)
= 5.5 kW
Room3, 4
Maximum Capacity × Room3 or 4 Capacity after the Temperature Correction/(Room1 to 4 Total Capacity after the Temperature
Correction)
= 25.5 × (8.0 × 0.94)/(5.6 × 1.03 × 2 + 8.0 × 0.94 × 2)
= 7.2 kW
Note: If CTx = CTi, please refer to the <Heating> section to calculate the Maximum Indoor Unit Capacity of Each Room.
Go on to the heating trial calculation since the selected units fulfill the cooling loads of Room 1 to 4.
OCH760
Design Condition
Model
Model
Model
Model
10
15
20
25
1.2
1.7
2.2
2.8
Model
Model
Model
Model
15
18
20
22
1.5
1.8
2.0
2.2
5.6 kW (Rated)
8.0 kW (Rated)
28.0 kW
OK: fulfills the load 5.4 kW
OK: fulfills the load 7.1 kW
39ºC
25.0 kW
27ºC
20ºC
5.4 kW
24ºC
18ºC
7.1 kW
20 m
Model
Model
Model
Model
Model
32
40
50
63
3.6
4.5
5.6
7.1
8.0
Model
Model
Model
Model
25
35
42
50
2.5
3.5
4.2
5.0
1.03 (Refer to Figure 1)
0.94 (Refer to Figure 1)
0.94 (Refer to Figure 2)
0.97 (Refer to Figure 3)
11
Model
Model
Model
Model
71
80
100
125
140
9.0
11.2
14.0
16.0
─
─
─
─
─
─
─
─
─
─
1.2
1.0
0.8
0.6
0.4
15
16
17
18
19
Indoor Temperature [°C W.B.]
Figure 1 Indoor unit temperature correction
To be used to correct indoor unit only
1.3
1.1
0.9
0.7
0.5
0.3
-15 -10
-5
0
5
10
15
Outdoor Temperature [°C D.B.]
Figure 2 Outdoor unit temperature correction
To be used to correct outdoor unit only
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0
20
40
60
80
Piping equivalent length (m)
Figure 3 Correction of refrigerant piping length
Unit: kW
Model
Model
200
250
22.4
28.0
─
─
─
─
20
21
22
23
24
Indoor temperature
19°C W.B
20
25
30
35
40 45
50
Total capacity of indoor unit
14.0
21.0
28.0
36.4
100
120
140
160
180
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