Midea ATOM MDV-V28WDHN1

Atom B Series VRF 50/60Hz
12
Midea Atom B Series VRF Engineering Data Book
 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 MDV-V42WDHN1(AtB)
cooling capacity
Table 1-5.9: Cooling capacity calculated by interpolation
CR
Outdoor
air
temp.
(°C DB)
Indoor air temp.
(°C DB / °C WB)
CR
Outdoor
air
temp.
(°C DB)
Indoor air temp.
(°C DB / °C WB)
25.8 / 18.0
25.8 / 18.0
TC
PI
TC
PI
kW
kW
kW
kW
100%
31
11.2
2.46
100%
33
11.2
2.63
33
11.2
2.76
35
11.2
2.80
B = 11.2
90%
31
10.1
2.11
90%
33
10.1
2.26
33
10.1
2.37
35
10.1
2.40
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 MDV-V42W/DHN1(At) (“C”) by using K1:
C = B × K1 = 11.2 × 0.968 =10.84kW
 The corrected capacity 10.84 kW is larger than required total heat load 10.5kW, so selection is complete.