Design of 3WAY VRF SYSTEM
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8
7
6
5
4
3
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1
1. Model Selecting and Capacity Calculator
<Cooling>
Ele
v
ation diff
erence (ft)
Base capacity
change rate
*1
92 90
88
86 84 82 80
78
76
94
96
98
100
%
0
33 66 98
131
164
197 230
262
295
328 361 394 427 459 492
0
33 66 98
131
164
197 230
262
295
328 361 394 427 459 492
164
131
98
66
33
0
–33
–66
–98
–131
Equivalent length (ft)
*1 Sample calculations
(System: 8 Ton, 164ft equivalent length, 49ft elevation
difference
The cooling capacity and heating capacity for this system are
found as shown below.)
●
Cooling operation
From the graph, the base capacity change rate is found to be
92.0%.
Capacity change rate is 92.0%.
(28.1kW × 92.0% = 25.8kW)
92.0% = 88,320 BTU/h
Cooling capacity is
88,320 BTU/h (28.1 kW)
●
Heating operation
From the graph, the base capacity change rate is found to be
97.2%.
Because the calculation result exceeds 97.2%, the capacity
change rate is 97.2%.
(31.6kW × 97.2% = 30.7kW)
Heating capacity is
105,000 BTU/h (30.7 kW)
Equivalent length (ft)
<Heating>
Base capacity
change rate
164
131
98
66
33
0
–33
–66
–98
–131
0
33 66 98 131 164 197 230 262 295 328 361 394 427 459 492
Ele
v
ation diff
erence (ft)
96,000 BTU/h ×
97.2% = 105,000 BTU/h
108,000 BTU/h ×
1-10. Capacity Correction Graph According to Tubing Length and Elevation Difference
Capacity change characteristics
The positive side for the elevation difference indicates that
the outdoor unit is installed at a higher position than the
indoor units. The negative side indicates the opposite.
Rated performance values
Item
Cooling
Heating
Type
Cooling capacity
BTU/h(kW)
Power consumption
kW
Heating capacity
BTU/h(kW)
Power consumption
kW
72
72,000(21.1)
5.30
81,000(23.7)
5.79
96
96,000(28.1)
7.75
108,000(31.6)
8.6
NOTE
TD831158-00̲3WAY̲VRF̲SYS.indb 16
TD831158-00̲3WAY̲VRF̲SYS.indb 16
2012/01/23 17:30:14
2012/01/23 17:30:14
