Panasonic S-12MT2U6 - System Design

Design of 3WAY VRF SYSTEM
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2. System Design
Design of 2WAY VRF SYSTEM
1. Model Selecting and Capacity Calculator
The capacity loss that is caused by the tubing length can be reduced by increasing the sizes of the discharge tubes and
suction tubes. See Table 14 and make the appropriate changes. However be sure that the total length does not exceed
the maximum.
* The only sizes which can be increased are the LM (main tube with the largest diameter) discharge tubes and suction tubes,
and the changes are limited to those shown in Table 14.
In addition, note that the additional refrigerant charge is determined only by the narrow-tube size.
Table 14 Correction coefficient for equivalent length when the size of the discharge tubes and suction tubes (LM)
is increased
* If the size of the discharge tubes and suction tubes (LM) have been increased, apply the correction coefficient from
Table 14 and calculate the equivalent length of the LM section.
Equivalent length of tubing after size increase
= Standard tubing equivalent length × Equivalent length correction coefficient
Equivalent length correction
coefficient
ø1/2"
䠄ø12.7䠅
ø5/8"
䠄ø15.88䠅
0.4
ø5/8"
䠄ø15.88䠅
ø3/4"
(ø19.05䠅
0.4
ø3/4"
(ø19.05䠅
ø7/8"
(ø22.22䠅
0.5
ø7/8"
(ø22.22䠅
1-ø1/8"
䠄ø28.58)
0.4
1-ø1/8"
䠄ø28.58)
1-ø3/8"
䠄ø34.92䠅
0.5
1-ø3/8"
䠄ø34.92䠅
1-ø5/8"
䠄ø41.28䠅
0.5
Tube diameter after change
discharge, suction tube
in.(mm)
Standard tubing diameter
discharge, suction tube
in.(mm)
2-1. System Example
Below are the tables created using the "PAC System Diagram Software".
Selection condition
Assume that installation
Outdoor unit
Room1
(indoor unit 1)
Room2
(indoor unit 2)
Room3
(indoor unit 3)
Room4
(indoor unit 4)
cooling
Air condition
(DB / WB)
91.0 /72.078.0/ 65.0 78.0 /65.078.0/ 65.0 78.0 /65.0
Max. load (BTU/h)
-49000 22000 2150
01
4000
heating
Air condition
(DB / WB)
37.9 /35.969.0/ 58.9 69.0/ 58.9 69.0 /58.969.0/ 58.9
Max. load (BTU/h)
-52000 22500 2200
01
6500
Actual tubing length 200 ft.90 ft.120 ft.150 ft
.2
00 ft.
Equivalent length
240 ft.108 ft.144 ft.180 ft
.2
40 ft.
Preliminary selection
Outdoor unit
Room1
(indoor unit 1)
Room2
(indoor unit 2)
Room3
(indoor unit 3)
Room4
(indoor unit 4)
selected model
Type 120Type 54 Type 24 Type 24 Type 15
Load (cooling / heating) (BTU/h)
-49000 / 52000 22000/ 2250021500 /22000 14000/ 16500
Rated capacity (cooling / heating) (BTU/h)
120000 /13500054600 /61400 25000/ 2700025000 /27000 15000/ 17000
Actual capacity (cooling / heating) (BTU/h)
- 49170 /52984 22059/ 2296821604 /22637 12508/ 13905
Calculate the actual capacity results according to the capacity calculation procedure on page"2-12" to "2-16".
Outdoor unit
Room1
(indoor unit 1)
Room2
(indoor unit 2)
Room3
(indoor unit 3)
Room4
(indoor unit 4)
Rated capacity (cooling / heating) (BTU/h)
120000 /13500054600 /61400 25000/ 2700025000 /27000 15000 /17000
(A) Capacity table
111000 /133016- /- -/--/- -/-
(B) Capa. Estimation Coef. : the Equiv. Tube Length
0.880/ 0.915-/- -/--/- -
/-
(C) Capa. Estimation Coef. : Temp. Conditions
-1.021 /1.000 1.021/ 1.0001.021 /1.000 1.021/ 1.000
(D) Capa. Estimation Coef. : Frosting / defrosting
-/0.890- -
--
(E) Estimation Capacity
-52173 /60137 23889/ 2644423889 /26444 14333/ 16650
(F) Capacity distribution ratio
-0.457 /0.464 0.209/ 0.2040.209 /0.204 0.125/ 0.128
(G) = (A) x (F)
-50674 /61686 23202/ 2712623202 /27126 13921 /17079
(H) Capa. Estimation Coef. : the Equiv. Tube Length
-0.951 /0.965 0.932/ 0.9510.912 /0.938 0.880/ 0.915
(I) = (C) x (H)
-0.970 /0.965 0.951/ 0.9510.931 /0.938 0.898/ 0.915
Actual capacity (cooling / heating) (BTU/h)
- 49170 /52984 22059/ 2296821604 /22637 12508/ 13905
Actual capacity = (G) x (I) x (D)
Indoor unit change
Increase by one rank because the capacity of the indoor unit 4 is lower than the maximum load.
Calculating the actual capacity in the same way as Preliminary selection.
Outdoor unit
Room1
(indoor unit 1)
Room2
(indoor unit 2)
Room3
(indoor unit 3)
Room4
(indoor unit 4)
selected model
Type 120Type 54 Type 24 Type 24 Type 18
Load (cooling / heating) (BTU/h)
-49000 /52000 22000/ 2250021500 /22000 14000/16500
Rated capacity (cooling / heating) (BTU/h)
120000 /13500054600 /61400 25000/ 2700025000 /27000 19000/ 21000
Actual capacity (cooling / heating) (BTU/h)
-49167 /51331 22058/ 2225221603 /21931 15843/16641
Outdoor unit change
The capacity of the indoor units 1, 2 and 3 is lower than the maximum load.
Increase the capacity of the outdoor unit by one rank because of inability to increase the indoor unit 1 by one rank.
Calculating the actual capacity in the same way as Preliminary selection.
Outdoor unit
Room1
(indoor unit 1)
Room2
(indoor unit 2)
Room3
(indoor
unit 3)
Room4
(indoor unit 4)
selected model
Type 144Type 54 Type 24 Type 24 Type 18
Load (cooling / heating) (BTU/h)
-49000 /52000 22000/ 2250021500 /22000 14000/ 16500
Rated capacity (cooling / heating) (BTU/h)
144000 /16200054600 /61400 25000/ 2700025000 /27000 19000/ 21000
Actual capacity (cooling / heating) (BTU/h)
-49165 /53872 22057/ 2335321602 /23017 15843/17465
For both cooling and heating in all rooms, actual capacity is now greater than or equal to the maximum load.
Selection is completed.
䠖㻌㻿㼛㼘㼑㼚㼛㼕㼐㻌㼂㼍㼘㼢㼑㻌㻷㼕㼠
Indoor
unit 1
Indoor
unit 2
Indoor
unit 3
Indoor
unit 4
60ft.
Elevation
difference :
Outdoor
unit 1
30ft.
15ft.
15ft.
15ft.
15ft.
15ft.
15ft.
30ft.
30ft.
50ft.
30ft.
TD831183-00_北米向け3WAY.indb 17 15/12/17 16:05:10