Fujitsu AOU48RLXFZ - Heating Example

2. MODEL SELECTION
HEATING EXAMPLE3-2-2.
EXAMPLE 3

(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, L1=32.8ft. (10m)
Design conditions
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Design temperature
●
Indoor : 65°F DB (18.3°C DB)
Outdoor : 50°F DB / 47°F WB (10.0°C DB / 8.3°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

Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Remark
A-1 Heating heat load Btu 8000 8000 8000 8000 8000 8000 8000 8000
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
Heating
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 change rate by
suction temperature of
indoor unit
59.4 / 54.0 = 1.10
See Fig.3
A-7
Total capacity at design
temperature ∑(TC
in
)
d
Btu 64800 x 1.10 = 71280
(A-4) x (A-6)
Calculate the Maximum capacity of outdoor unit

Remark
B-1 Outdoor unit model AOU48RLXFZ
B-2 Rated capacity (TC
out
)
r
Btu 54000
Heating
B-3 Capacity change rate by temperature conditions 59.7 / 54.0 = 1.106
See Fig.3
B-4 Capacity change rate by indoor units connecting capacity 62.1 / 54.0 = 1.15
See Fig.4
B-5 Compensation coefficient of pipe length 0.996 x 0.962 = 0.958
See 5-1.
B-6 Capacity change rate by frosting 1.00
See 5-2.
B-7 Maximum capacity of outdoor unit (TC
out
)
c
Btu
54000 x 1.106 x1.15 x 0.958 x1.00 =
65800
(B-2) x (B-3) x (B-4) x (B-5) x
(B-6)
Decide system capacity

Remark
C-1 System capacity Btu 65800
Smaller one of (A-7)
and (B-7)
Calculate actual capacity of each indoor unit

Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Remark
Actual capacity of each indoor
unit
Btu 8220 8220 8220 8220 8220 8220 8220 8220
(A-3) x (C-1) / (A-4)
Actual capacity of all indoor units is larger than heating heat load of each room.
- (02 - 09) -
MODEL SELECTION MODEL SELECTION