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9.1 Unit selection (Based on Cooling Load)
9.1.1 Actual Performance Data
Determine correct table according to the outdoor unit model and combination ratio. Enter the table at given indoor
and outdoor temperature and find the outdoor unit capacity and power input.
The individual indoor unit capacity (power input) can by calculated as follows.
IUC=OUC × INX/TNX
IUC: Each indoor unit capacity
OUC: Outdoors unit capacity
INX: Each indoor unit capacity index
TNX: Total capacity index
Then, correct the indoor unit capacity according to the piping length.
If the corrected capacity is smaller than the load, the size of indoor unit has to be increased and repeat the same
selection procedure.
9.1.2 Variation in capacity in accordance with the length of refrigerant piping.
(1) Cooling capacity modification
Cooling capacity modification=Refrigerating capacity x ( AxBxCxD) W
9. Capacity calculation due to capacity modication coefcient
d r a d n a t 8
y t i c a p a c
y t i c a p a C
n o i t a c i f i d o m
t n e i c i f f e o c
y t i c a p a C
n o i t a c i f i d o m
t n e i c i f f e o c
y t i c a p a C
n o i t a c i f i d o m
t n e i c i f f e o c
A.
Capacity compensation coefficient of
indoor air wet-bulb temperature condition
1.2
1.1
1.0
0.9
0.8
155 20 24
Indoor air wet-bulb temperature
C. Capacity modification coefficient
under airflow variation rate of indoor
unit group (only for duct unit)
1.1
1.0
0.9
80 90 100 110 120
airflow variation rate(% )
D. Capacity compensation suitable for total capability
of indoor unit group (cooling)
120
100
80
60
40
20
0 20 40 60 80 100 120 130
Total capacity of indoor unit group(%)
10
15
20
25 30
35
40
0.90
0.95
1.00
1.05
1.10
1.15
1.20
Inlet water temperature (
℃)
B. Capacity compensation coefficient of Inlet water
temperature condition
Capacity modification coefficient