11
OCH675E
4-1. SELECTION OF COOLING/HEATING UNITS
4
DATA
<Cooling>
Design Condition
Outdoor Design Dry Bulb Temperature
38ºC
Total Cooling Load
19.4 kW
Room1
Indoor Design Dry Bulb Temperature
27ºC
Indoor Design Wet Bulb Temperature
20ºC
Cooling Load
9.1 kW
Room2
Indoor Design Dry Bulb Temperature
24ºC
Indoor Design Wet Bulb Temperature
18ºC
Cooling Load
10.3 kW
<Other>
Indoor/Outdoor Equivalent Piping Length
40 m
Capacity of indoor unit
Unit: kW
P•FY Series
Model Number
for indoor unit Model 10 Model 15 Model 20 Model 25 Model 32 Model 40 Model 50 Model 63 Model 71 Model 80 Model 100 Model 125 Model 140 Model 200
Model
Capacity
1.2
1.7
2.2
2.8
3.6
4.5
5.6
7.1
8.0
9.0
11.2
14.0
16.0
22.4
M,S,P Series
Model Number
for indoor unit
─
Model 15 Model 20 Model 22 Model 25 Model 35 Model 42 Model 50 Model 60 Model 71 Model 100
─
─
─
Model
Capacity
─
1.5
2.0
2.2
2.5
3.5
4.2
5.0
6.0
7.1
10.0
─
─
─
1. Cooling Calculation
(1) Temporary Selection of Indoor Units
Room1
PEFY-P80
9.0kW (Rated)
Room2
PEFY-P100
11.2 kW (Rated)
(2) Total Indoor Units Capacity
P80 + P100 = P180
(3) Selection of Outdoor Unit
The P200 outdoor unit is selected as total indoor units capacity is P180
PUMY-P200
22.4 kW
(4) Total Indoor Units Capacity Correction Calculation
Room1
Indoor Design Wet Bulb Temperature Correction (20ºC)
1.03 (Refer to Figure 1)
Room2
Indoor Design Wet Bulb Temperature Correction (18ºC)
0.94 (Refer to Figure 1)
Total Indoor Units Capacity (CTi)
CTi = Σ (Indoor Unit Rating × Indoor Design Temperature Correction)
= 9.0 × 1.03 + 11.2 × 0.94
= 19.8 kW
(5) Outdoor Unit Correction Calculation
Outdoor Design Dry Bulb Temperature Correction (38ºC)
0.96 (Refer to Figure 2)
Piping Length Correction (40 m)
0.91 (Refer to Figure 3)
Total Outdoor Unit Capacity (CTo)
CTo = Outdoor Rating × Outdoor Design Temperature Correction × Piping Length Correction
= 22.4 × 0.96 × 0.91
= 19.6 kW
(6) Determination of Maximum System Capacity
Comparison of Capacity between Total Indoor Units Capacity (CTi) and Total Outdoor Unit Capacity (CTo)
CTi = 19.8 > CTo = 19.6, thus, select CTo.
CTx = CTo = 19.6 kW
(7) Comparison with Essential Load
Against the essential load 19.4kW, the maximum system capacity is 19.6 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
Maximum Capacity × Room1 Capacity after the Temperature Correction/(Room1,2 Total Capacity after the Temperature Correction
= 19.6 × (9.0 × 1.03)/(9.0 × 1.03 + 11.2 × 0.94)
= 9.2 kW
OK: fulfills the load 9.1 kW
Room2
Maximum Capacity × Room2 Capacity after the Temperature Correction/(Room1,2 Total Capacity after the Temperature Correction)
= 19.6 × (11.2 × 0.94)/(9.0 × 1.03 + 11.2 × 0.94)
= 10.4 kW
OK: fulfills the load 10.3 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, 2.
Indoor Temperature [°CW.B.]
Ratio of cooling capacity
15
16
17
18
19
20
21
22
23
24
0.4
0.6
0.8
1.0
1.2
Ratio of cooling capacity
Outdoor Temperature [°C D.B.]
-5.0
0.0
5.0
10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
Indoor Temperature
19°C W.B
Figure 1
Indoor unit temperature correction
To be used to correct indoor unit only
Figure 2
Outdoor unit temperature correction
To be used to correct outdoor unit
only
Figure 3
Correction of refrigerant piping length
[Cooling]
[Heating]
Heating
P200 model
11.2
16.8
22.4
29.1
Total capacity of indoor unit
Cooling capacity correction factor
Piping equivalent length (m)
0
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Total capacity of indoor unit
Cooling capacity correction factor
Piping equivalent length (m)
0
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
0.70
0.75
0.80
0.85
0.90
0.95
1.00
