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
30,000
Heating
37.0 / 35.0
69.0 / 55.0
69.0 / 55.0
55,000
296 ft
197 ft
* Equivalent length after size-up correction is used for the calculation of actual capacity.
355.2 ft
[276.5 ft]
236.4 ft
[157.7 ft]
35,000
230 ft
276.0 ft
[197.3 ft]
78.0 / 64.0
30,000
69.0 / 55.0
35,000
263 ft
315.6 ft
[236.9 ft]
78.0 / 64.0
18,500
69.0 / 55.0
20,000
296 ft
355.2 ft
[276.5 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 36
Type 18
50,000 /
55,000
30,000 /
35,000
35,000
18,500 /
20,000
30,000 /
30,000 /
18,500 /
39,000
36,000 /
39,000
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)
192,000 /
54,600 /
36,000 /
36,000 /
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) = 143,323.59/161,362.40
Ruc = 143,323.59/147,532.93 = 0.971 < 1
Ruh = 161,362.40/146,812.33 = 1.099 > 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) = 143,323.59/161,362.40
Ruh = 161,362.40/173,189.02 = 0.932 < 1
Ruc = 143,323.59/168,609.06 = 0.850 < 1
96 + 96
216,000
173,189.02
61,768.40
61,400.00
39,000.00
39,000.00
21,000.00
21,126.00
21,000
39,000
39,234.00
39,234.00
39,000
61,400
55,000
35,000
35,000
20,000
168,609.06 /
54,600.00 /
35,781.01 /
34,941.99 /
18,000.59 /
18,000.59 /
34,941.99 /
35,781.01 /
54,600.00
50,000 /
Type
19,410.57
36,048.20
36,048.20
56,752.81
54,600.00 /
35,781.01 /
34,941.99 /
18,000.59 /
21,126.00
18,000.59 /
34,941.99 /
39,234.00
35,781.01 /
39,234.00
54,600.00 /
61,768.40
147,532.93 /
146,812.33
168,000 /
189,000
54,600 /
61,400
36,000 /
30,000 /
Type 36
Type 18
Type
96 + 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
164 ft
33 ft
33 ft
66 ft
33 ft
33 ft
33 ft
Solenoid valve kit
TD831158-00̲3WAY̲VRF̲SYS.indb 18
TD831158-00̲3WAY̲VRF̲SYS.indb 18
2012/01/23 17:30:14
2012/01/23 17:30:14
Summary of Contents for U-72MF1U9
Page 118: ...Section 8 TENTATIVE ...