Midea MDVS-335W/DRN1 - Page 16

R410A DC Inverter VRF V4 Plus W Series 50Hz MCAC-VTSM-2016-04
14 Selection Procedure
2. Unit Selection (Based on cooling load)
2.1 Given condition
 Design condition (Cooling: Indoor 20°C (WB), Outdoor 35°C (DB))
 Cooling load:
Location
Room A
Room B
Room C
Room D
Room E
Room F
Load (kW)
2.1
2.8
3.5
4.6
5.8
7.2
 Power supply unit: Outdoor 380~415V-3Ph-50Hz, Indoor 220~240V-1Ph-50Hz.
 Pipe length: 50m
 Height difference: 30m
2.2 Indoor unit selection
Select the suitable capacity for condition of ‘Indoor 20°C (WB), Outdoor 35°C (DB)’ using indoor unit capacity
table. The selected result is as follows. (Assuming the indoor unit type is duct)
Location
Room A
Room B
Room C
Room D
Room E
Room F
Load (kW)
2.1
2.8
3.5
4.6
5.8
7.2
Unit size
22
28
36
45
56
71
Capacity (kW)
2.3
2.9
3.7
4.8
6.0
7.5
2.3 Outdoor unit selection
a) Assume the indoor unit and outdoor unit combination as follows
 Calculate the total nominal capacity of indoor units in the combination according to the above table:
2.2×1+2.8×1+3.6×1+4.5×1+5.6× 1+7.1×1=25.8kW
 Select outdoor unit: MDVS-280(10)W/DRN1 which has nominal cooling capacity: 28kW.
 Calculate the proportion between ① and ②: 258/280= 92%
b) Result : Because the proportion is within 50～130%, it is a Right selection.
c) Real function data with indoor unit combination
 For the 92% combination, calculate the cooling capacity of outdoor unit (MDV-280(10)W/DRN1(B)).
26.65KW ←90% (Indoor temperature : WB 20°C, Outdoor temperature: DB 35°C)
29.61KW ←100%(Indoor temperature : WB 20°C, Outdoor temperature: DB 35°C)
Then calculated the outdoor capacity in 92% combination index:
Therefore: 26.65+ {(29.61-26.65)/ 10} ×2= 27.24;
 Outdoor unit (MDVS-280(10)W/DRN1 cooling temperature: DB 35°C
 Capacity modification coefficient with pipe length (50m) and height difference (30m): 0.958
 Each indoor unit cooling capacity:
MDV-D22T2: 27.24 × 22/258 × 0.958 = 2.22(kW)
MDV-D28T2: 27.24 × 28/258 ×0.958 = 2.83 (kW)
MDV-D36T2: 27.24 × 36/258 ×0.958 = 3.64 (kW)
MDV-D45T2: 27.24 × 45/258 ×0.958 = 4.55 (kW)
MDV-D56T2: 27.24 × 56/258 ×0.958 = 5.66 (kW)
MDV-D71T2: 27.24 × 71/258 ×0.958 = 7.18 (kW)
Location
Room A
Room B
Room C
Room D
Room E
Room F
Load (kW)
2.1
2.8
3.5
4.6
5.8
7.2
Unit size
22
28
36
45
56
71
Capacity (kW)
2.22
2.83
3.64
4.55
5.66
7.18
2.4 Conclusion
Generally, we think this result is acceptable, so we can think we have accomplished the calculation. But if you
think this result is not acceptable, you can repeat the above process.
Remark: In this sample, we don’t consider the other capacity modification index and assume them are 1.0.
For more details about the effect factor such as outside ambient/inside ambient DB/WD, please refer to the
performance table of indoor and outdoor units.