Mitsubishi Electric City Multi PUMY-SP112VKM Technical & Service Manual page 12

<Heating>
Outdoor Design Wet Bulb Temperature
Total Heating Load
Room1
Indoor Design Dry Bulb Temperature
Heating Load
Room2
Indoor Design Dry Bulb Temperature
Heating Load
<Other>
Indoor/Outdoor Equivalent Piping Length
Capacity of indoor unit
Model Number
Model 15
for indoor unit
P•FY Series
Model Capacity
Model Number
M Series
Model 15
for indoor unit
S Series [kW type]
P Series
Model Capacity
2. Heating Calculation
(1) Temporary Selection of Indoor Units
Room1
PEFY-P40
Room2
PEFY-P50
(2) Total Indoor Units Capacity
P40 + P50 = P90
(3) Selection of Outdoor Unit
The SP112 outdoor unit is selected as total indoor units capacity is P90
PUMY-SP112
(4) Total Indoor Units Capacity Correction Calculation
Room1
Indoor Design Dry Bulb Temperature Correction (21ºC)
Room2
Indoor Design Dry Bulb Temperature Correction (23ºC)
Total Indoor Units Capacity (CTi)
CTi = Σ (Indoor Unit Rating × Indoor Design Temperature Correction)
= 5.0 × 0.96 + 6.3 × 0.88
= 10.3 kW
(5) Outdoor Unit Correction Calculation
Outdoor Design Wet Bulb Temperature Correction (2ºC)
Piping Length Correction (100 m)
Defrost Correction
Total Outdoor Unit Capacity (CTo)
CTo = Outdoor Unit Rating × Outdoor Design Temperature Correction × Piping Length
Correction × Defrost Correction
= 14.0 × 1.0 × 0.94 × 0.89
= 11.7 kW
(6) Determination of Maximum System Capacity
Comparison of Capacity between Total Indoor Units Capacity (CTi) and Total Outdoor Unit Capacity (CTo)
CTi = 10.3 < CTo = 11.7, thus, select CTi.
CTx = CTi = 10.3 kW
(7) Comparison with Essential Load
Against the essential load 10.3kW, the maximum system capacity is 10.3 kW: Proper indoor units have been selected.
(8) Calculation of Maximum Indoor Unit Capacity of Each Room
CTx = CTo, thus, calculate by the calculation below
Room1
Indoor Unit Rating × Indoor Design Temperature Correction
= 5.0 × 0.96
= 4.8 kW
Room2
Indoor Unit Rating × Indoor Design Temperature Correction
= 6.3× 0.88
= 5.5 kW
Note: If CTx = CTo, please refer to the <Cooling> section to calculate the Maximum Indoor Unit Capacity of Each Room.
Completed selecting units since the selected units fulfill the heating loads of Room 1, 2.
OCH668B
Design Condition
Model 20 Model 25 Model 32 Model 40
1.9 2.5 3.2 4.0 5.0
Model 18
Model 20 Model 22 Model 25 Model 35 Model 42 Model 50 Model 60 Model 71
1.7 2.1 2.3 2.5
OK: fulfills the load 4.8 kW
OK: fulfills the load 5.5 kW
2ºC
10.3 kW
21ºC
4.8 kW
23ºC
5.5 kW
100 m
Model 50 Model 63 Model 71 Model 80
6.3 8.0 9.0 10.0
2.9 4.0 4.8 5.7 6.9
5.0 kW (Rated)
6.3 kW (Rated)
Figure 4 Indoor unit temperature correction
14.0 kW
0.96 (Refer to Figure 4)
0.88 (Refer to Figure 4)
Figure 5 Outdoor unit temperature correction
1.0 (Refer to Figure 5)
0.94 (Refer to Figure 6)
0.89 (Refer to Table 1)
Figure 6 Correction of refrigerant piping length
Table 1 Table of correction factor at frost and defrost
Outdoor inlet air temp. °C 6 4
PUMY-SP112,125,140VKM 1.0 0.98
PUMY-SP112,125,140YKM 1.0 0.98
12
Model 100 Model 125 Model 140
12.5 16.0 18.0
Model 80 Model 100
8.1 9.3 11.2
1.2
1.1
1.0
0.9
0.8
0.7
0.6
15 16 17 18 19 20 21 22 23 24
Indoor Temperature [°CD.B.]
To be used to correct indoor unit only
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
−20 −15 −10 −5 0 5
Outdoor Temperature [°C W.B.]
To be used to correct outdoor unit only
1
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0 20 40 60 80 100 120 140 160
Piping equivalent length (m)
2 0 −2 −4 −6 −8 −10
0.89 0.88 0.89 0.90 0.95 0.95 0.95
0.89 0.88 0.89 0.90 0.95 0.95 0.95
25 26 27
20°C D.B
10 15
180 200
−15 −20
0.95 0.95
0.95 0.95