Mitsubishi Electric CITY MULTI PUHY-HP72-240TNU-A Data Book page 39

8. CAPACITY TABLES
<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
2. Heating 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 Dry Bulb Temperature Correction (77ºF)
Room2
Indoor Design Dry Bulb Temperature Correction (77ºF)
Total Indoor Units Capacity (CTi)
CT
= 64,000 BTU/h
(5) Outdoor Unit Correction Calculation
Outdoor Design Wet Bulb Temperature Correction (37ºF)
Piping Length Correction (100 ft.)
Defrost Correction
Total Outdoor Unit Capacity (CTo)
CTo = Outdoor Unit Rating
Correction Defrost Correction
= 67,000 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 = 64,000 < CTo = 67,000, thus, select CTi.
CTx = CTi = 64,000 BTU/h
(7) Comparison with Essential Load
Against the essential load 62,000BTU/h, the maximum system capacity is 64,000BTU/h: Proper outdoor units have been selected.
(8) Calculation of Maximum Indoor Unit Capacity of Each Room
CTx = CTi, thus, calculate by the calculation below
Room1
Indoor Unit Rating Indoor Design Temperature Correction
= 32,000 BTU/h
Room2
Indoor Unit Rating Indoor Design Temperature Correction
= 32,000 BTU/h
Completed selecting units since the selected units fulfill the heating loads of Room 1, 2.
MEES21K108
Design Condition
Outdoor Design Temperature Correction
OK: fulfills the load 31,000BTU/h
OK: fulfills the load 31,000BTU/h
37 ºF
62,000 BTU/h
77 ºF
31,000 BTU/h
77 ºF
31,000 BTU/h
100 ft.
40,000 BTU/h (Nominal)
40,000 BTU/h (Nominal)
Fig.4 Indoor unit temperature correction
80,000 BTU/h
0.80 (Refer to Fig.4)
0.80 (Refer to Fig.4)
Fig.5 Outdoor unit temperature correction
0.99 (Refer to Fig.5)
0.98 (Refer to Fig.6)
0.87 (Refer to Tbl.1)
Piping Length
Fig.6 Correction of refrigerant piping length
Tbl.1 Table of correction factor at frost and defrost
Outdoor inlet air temp. °CWB 6 4
Outdoor inlet air temp. °FWB 43 39
PUHY-P72 1.00 0.95
PUHY-P96 1.00 0.95
PUHY-P120 1.00 0.93
PUHY-P144 1.00 0.93
PUHY-P168 1.00 0.93
Hyper Heating Inverter Y-Series
0.8
Indoor Temperature [°FD.B.]
To be used to correct indoor unit only
0.99
37
Outdoor Temperature [°FW.B.]
To be used to correct outdoor unit only
0.98
100
Piping equivalent length (ft.)
2 1 0 -2 -4 -6 -8
36 34 32 28 25 21 18
0.84 0.83 0.83 0.87 0.90 0.95 0.95
0.84 0.83 0.83 0.87 0.90 0.95 0.95
0.82 0.80 0.82 0.86 0.90 0.90 0.95
0.82 0.80 0.82 0.86 0.90 0.90 0.95
0.82 0.80 0.82 0.86 0.90 0.90 0.95
77
-10 -20
14 -4
0.95 0.95
0.95 0.95
0.95 0.95
0.95 0.95
0.95 0.95
37