Mitsubishi Electric CITY MULTI PUHY-P72-432TNU-A Data Book page 107

8. CAPACITY TABLES
<Cooling>
Outdoor Design Dry Bulb Temperature
Total Cooling Load
Room1
Indoor Design Dry Bulb Temperature
Indoor Design Wet Bulb Temperature
Cooling Load
Room2
Indoor Design Dry Bulb Temperature
Indoor Design Wet Bulb Temperature
Cooling Load
<Other>
Indoor/Outdoor Equivalent Piping Length
1. Cooling Calculation
(1) Temporary Selection of Indoor Units
Room1
PEFY-P36
Room2
PEFY-P36
(2) Total Indoor Units Capacity
P36 + P36 = P72
(3) Selection of Outdoor Unit
The P72 outdoor unit is selected as total indoor units capacity is P72
PUHY-P72
(4) Total Indoor Units Capacity Correction Calculation
Room1
Indoor Design Wet Bulb Temperature Correction (68ºF)
Room2
Indoor Design Wet Bulb Temperature Correction (64ºF)
Total Indoor Units Capacity (CTi)
CT
= 71,200 BTU/h
(5) Outdoor Unit Correction Calculation
Outdoor Design Dry Bulb Temperature Correction (99ºF)
Piping Length Correction (100 ft.)
Total Outdoor Unit Capacity (CTo)
= 67,700 BTU/h
(6) Determination of Maximum System Capacity (CTx)
Comparison of Capacity between Total Indoor Units Capacity (CTi) and Total Outdoor Unit Capacity (CTo)
CTi = 71,200 > CTo = 67,700, thus, select CTo.
CTx = CTo = 67,700 BTU/h
(7) Comparison with Essential Load
Against the essential load 63,000BTU/h, the maximum system capacity is 67,700BTU/h: 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
= 34,800 BTU/h
Room2
= 32,800 BTU/h
Go on to the heating trial calculation since the selected units fulfill the cooling loads of Room 1, 2.
MEES23K040
Design Condition
36,000 BTU/h (Nominal)
36,000 BTU/h (Nominal)
OK: fulfills the load 31,000BTU/h
OK: fulfills the load 32,000BTU/h
99 ºF
63,000 BTU/h
81 ºF
68 ºF
31,000 BTU/h
75 ºF
64 ºF
32,000 BTU/h
100 ft.
1.02
0.96
Fig.1 Indoor unit temperature correction
To be used to correct indoor unit only
72,000 BTU/h
0.99
1.02 (Refer to Fig.1)
0.96 (Refer to Fig.1)
Fig.2 Outdoor unit temperature correction
To be used to correct outdoor unit only
0.95
0.99 (Refer to Fig.2)
0.95 (Refer to Fig.3)
Fig.3 Correction of refrigerant piping length
Y-Series
64 68
Indoor Temperature [°FW.B.]
99
Outdoor Temperature [°FD.B.]
Total capacity of indoor unit
V=Outdoor unit capacity
100
Piping equivalent length (ft.)
104