Technical Data Manual

Design of 3WAY VRF SYSTEM
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2. System Design
The indoor unit in room 4, where the corrected indoor unit capacity is less than the maximum load, is increased by one rank.
Outdoor unit
Room 1
(indoor unit 1)
Room 2
(indoor unit 2)
Room 3
(indoor unit 3)
Room 4
(indoor unit 4)
Selected model
Type
Load (cooling/heating) (BTU/h)
Rated capacity (cooling/heating) (BTU/h)
(5) Corrected capacity (cooling/heating) (BTU/h)
(7) Actual capacity (cooling/heating) (BTU/h)
(7) Actual capacity (BTU/h)
For both cooling and heating in all rooms, actual capacity is now greater than or equal to the maximum load. Selection is completed.
[From calculation of the correction coefficient to calculation of actual capacity]
Outdoor unit
Room 1
(indoor unit 1)
Room 2
(indoor unit 2)
Room 3
(indoor unit 3)
Room 4
(indoor unit 4)
Rated capacity (cooling/heating) (BTU/h)
Correction coefficient
Model
Distribution ratio
(1)
(2) Temp. condition
(3) Tubing length, elevation difference
(4) Frosting/defrosting
Result of (2) × (3)
Correction coefficient applied to indoor unit *1
(5) Corrected capacity (BTU/h) *2
The actual capacity is calculated as shown below.
Cooling: Ruc = (54,600 + 35,842 + 18,472 + 23,684) / 146,710 = 0.904 < 1
Therefore,
Actual cooling capacity of each indoor unit = Corrected cooling capacity of each indoor unit
(In other words, the correction coefficient (6) for the corrected capacity ratio is 1.)
Heating: Ruh = (60,631 + 38,512 + 20,737 + 26,662) / 146,242 = 1.021 > 1
96 + 72
Type 54 Type 36 Type 18 Type 24
168,000 /
189,000
50,000 /
52,000
54,600 /
60,631
146,710 /
146,242
54,600 /
61,400
54,600 /
61,768
32,000 /
33,000
35,842 /
38,512
36,000 /
39,000
35,842 /
39,234
18,000 /
19,000
18,472 /
20,737
19,000 /
21,000
18,472 /
21,126
17,900 /
21,500
Selected model
Type
Load (cooling/heating) (BTU/h)
96 + 72
Type 54 Type 36 Type 18 Type 24
50,000 /
52,000
32,000 /
33,000
18,000 /
19,000
17,900 /
21,500
23,684 /
26,662
25,000 /
27,000
168,000 /
189,000
1.0000 /
1.0000
54,600 /
61,400
36,000 /
39,000
19,000 /
21,000
25,000 /
27,000
1.0203 /
0.9688
0.9474 /
1.0060
0.9474 /
1.0060
0.9474 /
1.0060
0.9474 /
1.0060
0.8559 /
0.8974
0.9205 /
0.9436
0.8995 /
0.9285
0.8783 /
0.9134
0.8559 /
0.8974
146,710 /
146,242
54,600 /
61,768
35,842 /
39,234
18,472 /
21,126
23,685 /
27,162
54,600 /
60,631
35,842 /
38,512
18,472 /
20,737
23,684 /
26,662
1.0189 /
1.0578
1.0509 /
1.0346
1.0755 /
1.0515
1.0262 /
1.0178
1.0000 /
1.0000
1.0000 /
1.0000
0.9956 /
1.0000
0.9722 /
1.0000
0.9474 /
1.0000
1.0000 /
0.9816
1.0000 /
0.9816
1.0000 /
0.9816
1.0000 /
0.9816
23,685 /
27,162
0.8900
0.9956 /
1.0408
0.9722 /
1.0239
0.9474 /
1.0060
Ruh = 149,290 / 146,242 = 1.021 > 1Ruc = 132,600 / 146,710 = 0.904 < 1
Total corrected capacity of indoor units (cooling/heating) = 132,600 / 149,290
Indoor unit changes
(2) Calculate the final selection results according to the capacity calculation procedure.
(Cooling/heating)
(6) Correction coefficient for corrected capacity ratio
*1: This varies depending on the values of (2) and (2) × (Distribution ratio in (3)).
*2: Corrected outdoor unit capacity = Rated outdoor unit capacity × (1) × (2) × (3) × (4)
TD831158-02_3WAY_VRF_SYS.indb 19TD831158-02_3WAY_VRF_SYS.indb 19 2013/06/18 11:46:362013/06/18 11:46:36