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= 34.2 kBtu/h
The capacity is enough for the cooling load of Room 2 (33.4 kBtu/h): A proper indoor unit is selected.
Note:
• Go on to the selection of units for heating after the selection for cooling has successfully completed. If failed, try
again until proper units are selected.
5-1-2. Heating
Outdoor wet bulb temperature
Total heating load
Room 1
Indoor dry bulb temperature
Heating load
Room 2
Indoor dry bulb temperature
Heating load
Other
Indoor/Outdoor piping equivalent length
Capacity of indoor unit
Model class of indoor unit
Model capacity (kBtu/h)
Model name
06
SVZ
-
SLZ-KF
-
SEZ-KD
-
MFZ-KJ
-
MLZ-KP
-
MSZ-FH
6.0
MSZ-FS
6.0
MSZ-GL
6.0
MSZ-EF
-
PEAD
-
PLA
-
■ Heating calculation
• Tentative selection of indoor units
Room1: PEFY-P30
Room2: PEFY-P36
In this case, the total capacity is 74.0. (34.0 + 40.0 = 74.0)
• Tentative selection of outdoor unit
Proper outdoor unit in this case is SM72TAM as the total capacity of the indoor units is 74.0.
SM72TAM
• Calculation for the corrected capacity of the total indoor units (CTi)
Correction factor for indoor temperature: Room 1 (69.8°F)
CTi = Σ (Rated capacity of indoor unit × Correction factor for indoor temperature)
= 34.0 × 1.00 + 40.0 × 0.92
= 70.8 kW
• Calculation for the corrected capacity of the outdoor unit (CTo)
Correction factor for outdoor temperature (35.6°F WB)
Correction factor for piping length (196 ft)
Correction factor for defrosting
CTo = Rated capacity of outdoor unit × Correction factor for outdoor temperature × Correction factor for piping length ×
Correction factor for defrosting (× G(CTi))*1
= 80.0 × 1.00 × 0.96 × 0.89
= 68.35 kBtu/h
*1. G(CTi) is used only when greater than 100% indoor model size are connected in total. Refer to Standard capacity
diagram.
Table 1 Table of correction factor for frosting and defrosting
Outdoor inlet air temp. [°F (°C) W.B.]
Correction factor
• Determination of maximum system capacity (CTx)
Comparison between CTi and CTo:
CTi = 70.8 > CTo = 68.35, thus, select CTo.
CTx = CTo = 68.35 kBtu/h
OCH800A_16
Design condition
04
05
06
08
12
15
4.5
5.6
6.7
9.0
13.5 17.0 20.0 27.0 30.0 34.0 40.0 54.0 60.0 80.0 108.0
Capacity class
09
12
15
18
-
12.0
-
18.0
10.2
13.7
17.1
-
10.9
13.6
18.0
17.2
10.9
13.0
18.0
21.0
10.9
13.0
-
21.0
10.9
13.6
18.0
20.3
10.9
13.6
18.0
20.3
10.9
14.4
18.0
21.6
10.9
13.0
18.0
21.0
10.9
13.5
15.7
18.0
-
13.5
-
18.0
34.0 kBtu/h (Nominal)
40.0 kBtu/h (Nominal)
80.0 kBtu/h
Room 2 (73.4°F)
43(6)
37(4)
36(2)
1.00
0.98
0.89
35.6ºF (2.0ºC)
67.5 kBtu/h
69.8ºF (21.0ºC)
32.2 kBtu/h
73.4ºF (23.0ºC)
35.3 kBtu/h
196 ft
18
24
27
30
36
48
24
30
36
27.0
34.0
40.0
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
27.6
-
-
-
-
-
26.0
34.0
40.0
26.0
34.0
40.0
32(0)
28(-2)
25(-4)
21(-6)
0.88
0.89
0.90
0.95
54
72
96
1.00 (Refer to Figure 3 in 5-2-2.)
0.92 (Refer to Figure 3 in 5-2-2.)
1.00 (Refer to Figure 4 in 5-2-2.)
0.96 (Refer to Figure 8 in 5-5-2.)
0.89 (Refer to Table 1.)
18(-8)
14(-10)
5(-15)
-4(-20) -13(-25)
0.95
0.95
0.95
0.95
0.95
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