Technical Data Manual

Design of 3WAY VRF SYSTEM
2 - 18
8
7
6
5
4
3
2
1
2. System Design
(1) Below are the tables created using the “PAC System Diagram Software.” Details of the calculations are shown in (2).
Selection conditions
Outdoor unit
Room 1
(indoor unit 1)
Room 2
(indoor unit 2)
Room 3
(indoor unit 3)
Room 4
(indoor unit 4)
Cooling
91.0 / 72.0 78.0 / 64.0
50,000
78.0 / 64.0
32,000
Heating
37.0 / 35.0 69.0 / 55.0 69.0 / 55.0
52,000
306 ft 205 ft
* Equivalent length after size-up correction is used for the calculation of actual capacity.
367.2 ft
[285.6 ft]
246 ft
[164.4 ft]
33,000
238 ft
285.6 ft
[204 ft]
78.0 / 64.0
18,000
69.0 / 55.0
19,000
271 ft
325.2 ft
[243.6 ft]
78.0 / 64.0
17,900
69.0 / 55.0
21,500
306 ft
367.2 ft
[285.6 ft]
Preliminary selection
Outdoor unit
Room 1
(indoor unit 1)
Room 2
(indoor unit 2)
Room 3
(indoor unit 3)
Room 4
(indoor unit 4)
Type 36
Type 36 Type 18 Type 18
50,000 /
52,000
32,000 /
33,000 19,000
17,900 /
21,500
32,000 / 18,000 / 17,900 /
39,000
19,000 /
21,000
19,000 /
21,000
(5) Corrected capacity (cooling/heating) (BTU/h)
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 54
Load (cooling/heating) (BTU/h)
Rated capacity (cooling/heating) (BTU/h)
168,000 / 54,600 / 36,000 / 19,000 / 19,000 /
(5) Corrected capacity (cooling/heating) (BTU/h)
(7) Actual capacity (cooling/heating) (BTU/h)
2-1. System Example
As the maximum tubing length (equivalent length) is over 295ft. in the following selection sample, the item (3) is applied due
to the main tube size up.
Air condition (DB/WB)
Max. load (BTU/h)
Air condition (DB/WB)
Max. load (BTU/h)
Actual tubing length
Equivalent length (with consideration for curves, etc.)
[* Equivalent length after size-up correction]
Selected model
Load (cooling/heating) (BTU/h)
Rated capacity (cooling/heating) (BTU/h)
(7) Actual capacity (cooling/heating) (BTU/h)
Total corrected capacity of indoor units (cooling/heating) = 126,915 / 143,254
Ruc = 126,915 / 125,752 = 1.009 > 1 Ruh = 143,254 / 120,304 = 1.191 > 1
Outdoor unit changes
The corrected outdoor unit capacity is less than the total corrected capacity of all indoor units in the system. As a result, the actual capacity of
each indoor unit is less than the maximum load. Therefore the outdoor unit is increased by one rank.
Total corrected capacity of indoor units (cooling/heating) = 126,915 / 143,254
Ruh = 143,254 / 146,242 = 0.980 < 1Ruc = 126,915 / 146,710 = 0.865 < 1
96 + 72
189,000
146,242 61,768
61,400 39,000 21,000 21,000
21,126
21,00021,000
21,12639,234
39,00061,400
52,000 33,000 19,000 21,500
146,710 / 54,600 / 35,842 / 18,472 / 18,000 /
18,000 /18,472 /35,842 /54,600 /
50,000 /
Type
18,07918,07933,57652,861
52,223 / 35,595 / 18,344 / 17,876 /
21,126
18,000 /18,472 /
21,126
35,842 /
39,234
54,600 /
61,768
125,752 /
120,304
139,000 /
157,000
54,600 /
61,400
36,000 /
18,000 /
Type 18 Type 18
Type
72 + 72
Type 54
Outdoor
unit 1
Indoor
unit 1
Indoor
unit 2
Indoor
unit 3
Indoor
unit 4
Outdoor
unit 2
Elevation
difference: 33 ft
170 ft
33 ft 33 ft 66 ft
33 ft 33 ft 33 ft
Solenoid valve kit
TD831158-02_3WAY_VRF_SYS.indb 18TD831158-02_3WAY_VRF_SYS.indb 18 2013/06/18 11:46:352013/06/18 11:46:35