BGH BV-V28W/DHN1 Manual page 13

VRF 50/60Hz
the required heat load is 10.5kW.
Provisionally select an outdoor unit using the sum of the capacity indexes (CIs) of the selected indoor units (as shown
•
in Table 1-5.5), ensuring that the combination ratio is between 50% and 130%. Refer to Table 1-5.6. As the sum of CIs
of the indoor units is 120. For the 10kW unit is not suitable, try to select 12kW unit.
• The number of connected indoor units is 4 and the maximum number of connected indoor units on the 12kW outdoor
unit is 7, so the number of connected indoor units is within the limitation.
• Calculate the corrected capacity of the outdoor unit:
a) The sum of the indoor unit CIs is 120 and the CI of the 12kW outdoor unit is 120, so the combination ratio is 120 /
120 = 100%.
b) Using the outdoor unit's cooling capacity table, interpolate to obtain the capacity ("B") corrected for outdoor air
temperature, indoor air temperature, and combination ratio. Refer to Tables 1-5.8 and 1-5.9.
Table 1-5.8: Extract from Table 2-7.3 BV-V42W/DHN1(At)
cooling capacity
Outdoor
CR
temp.
(°C DB)
100%
90%
c) Find the correction factor for piping length and level difference ("K1")
Figure 1-5.4: Atom rate of change in cooling capacity
d) Calculate the corrected capacity of BV-V42W/DHN1(At) ("C") by using K1:
• The corrected capacity 10.84 kW is larger than required total heat load 10.5kW, so selection is complete.
12
Indoor air temp.
(°C DB / °C WB)
air
25.8 / 18.0
TC
kW
31 11.2
33 11.2
35
11.2
31 10.1
33 10.1
35 10.1
C = B × K1 = 11.2 × 0.968 =10.84kW
Table 1-5.9: Cooling capacity calculated by interpolation
CR
PI
kW
2.46
2.63 100%
2.80
2.11
2.26 90%
2.40
Indoor air temp.
Outdoor
(°C DB / °C WB)
air
25.8 / 18.0
temp.
TC
(°C DB)
kW
33 11.2
B = 11.2
33 10.1
PI
kW
2.76
2.37