Design and Technical Manual

2. MODEL SELECTION
EXAMPLE 4

(When the connecting capacity for indoor unit is 100% or more)
Branch
box
Branch
box
Branch
box
Outdoor unit
Indoor unit 1 Indoor unit 2 Indoor unit 3 Indoor unit 4 Indoor unit 5 Indoor unit 6 Indoor unit 7 Indoor unit 8
Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Main Piping length, L1=32.8ft. (10m) Branch Piping length, L2=32.8ft. (10m)
Design conditions
z
Design temperature

●
Indoor : 65°F DB (18.3°C DB)
Outdoor : 41°F DB / 37°F WB (5.0°C DB / 2.8°C WB)
Pipe length

●
Main piping length : L1=32.8ft. (10m)
Branch piping length : L2=32.8ft. (10m)
Operation mode: Heating

●
Selection of indoor unit
z
Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Remark
A-1 Heating heat load Btu 6500 6500 6500 6500 6500 6500 6500 6500
A-2 Indoor unit models ASU7 ASU7 ASU7 ASU7 ASU7 ASU7 ASU7 ASU7
A-3 Rated capacity (TC
in
)
r
Btu 8100 8100 8100 8100 8100 8100 8100 8100
See 2-2.
A-4 Total rated capacity ∑(TC
in
)
r
Btu 8100 x 8 = 64800
Sum of A-3
A-5
Connecting indoor unit
capacity (Cp)
64800 / 54000 = 120%
A-6
Capacity at design
temperature (TC
in
)
d
Btu 8770 8770 8770 8770 8770 8770 8770 8770
See 6-2.
A-7
Total capacity at design
temperature ∑(TC
in
)
d
Btu 8770 x 8 = 70160
Sum of A-6
Calculate the Maximum capacity of outdoor unit
z
Remark
B-1 Outdoor unit model AOU48RLXFZ1
B-2 Rated capacity (TC
out
)
r
Btu 54000
See 2-1.
B-3 Capacity change rate by temperature conditions 55.3 / 54.0 = 1.024
See Fig.3
B-4 Capacity change rate by indoor units connecting capacity Btu 62100
See Fig.4
B-5 Compensation coefcient of pipe length 0.996 x 0.962 = 0.958
See 5-1.
B-6 Capacity change rate by frosting 0.90
See 5-2.
B-7 Maximum capacity of outdoor unit (TC
out
)
c
Btu 62100 x 1.024 x 0.958 x 0.90 = 54830
(B-4) x (B-3) x (B-5) x (B-6)
Decide system capacity
z
Remark
C-1 System capacity Btu 54830
Smaller one of (A-7)
and (B-7)
Calculate actual capacity of each indoor unit
z
Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Remark
Actual capacity of each indoor
unit
Btu 6850 6850 6850 6850 6850 6850 6850 6850
(A-3) x (C-1) / (A-4)
Actual capacity of all indoor units is larger than heating heat load of each room.
- (02 - 10) -
MODEL SELECTION MODEL SELECTION