Engineering Manual

B-119
n: Total number of the indoor units
k: Number of the indoor unit
c
k
: Outdoor unit power input coefficient of k indoor unit room temp.
M
k
: Number part of the k indoor unit model (e.g. P80 → 80)
<Cooling>
3. Power input of outdoor unit
Outdoor unit : MXZ-4C36
Indoor unit 1 : MSZ-FH15
Indoor unit 2 : MSZ-FH18
(1) Rated power input of outdoor unit 2.57 kW
1.04 (Refer to “6-2. CORRECTING BY TEMPERATURE”.)
(2) Calculation of the average indoor temperature power input coefficient
Coefficient of the outdoor unit for indoor unit 1 (Outdoor temp. 98.6°F [37.0°C] D.B., Indoor temp. 68.0°F [20.0°C] W.B.)
Maximum System Capacity (CTx) = Total Outdoor unit Capacity (CTo), so use the following formula
Total Indoor units capacity
15 + 18 = 33, thus, (CTi) = 0.9 (Refer to the tables in “9.STANDARD CAPACITY DIAGRAM”.)
PIo = Outdoor unit Cooling Rated Power Input × Correction Coefficient of Indoor temperature × (CTi)
= 2.57 × 0.94 × 0.9
= 2.2 kW
0.85 (Refer to “6-2. CORRECTING BY TEMPERATURE”.)
Coefficient of the outdoor unit for indoor unit 2 (Outdoor temp. 98.6°F [37.0°C] D.B., Indoor temp. 64.4°F [18.0°C] W.B.)
= 1.04 × 15/(15 + 18) + 0.85 × 18/(15 + 18)
= 0.94
n
k=1
n
k=1
Average indoor temp. power input coefficient ( c
ave
) = ∑ {c
k
× (M
k
/ ∑ M
k
)}
(4) Outdoor power input (PIo)
(3) Coefficient of the partial load (CTi)
n: Total number of the indoor units
k: Number of the indoor unit
c
k
: Outdoor unit power input coefficient of k indoor unit room temp.
M
k
: Number part of the k indoor unit model (e.g. P80 → 80)
<Heating>
(1) Rated power input of outdoor unit 3.34 kW
1.34 (Refer to “6-2. CORRECTING BY TEMPERATURE”.)
(2) Calculation of the average indoor temperature power input coefficient
Coefficient of the outdoor unit for indoor unit 1 (Outdoor temp. 26.6°F [−3°C] W.B., Indoor temp. 68.0°F [20°C] D.B.)
Maximum System Capacity (CTx) = Total Indoor unit Capacity (CTi), so use the following formula
PIo = Outdoor unit Heating Rated Power Input × Correction Coefficient of Indoor temperature × (CTi)
= 3.34 × 1.20 × 0.9
= 3.61 kW
1.09 (Refer to “6-2. CORRECTING BY TEMPERATURE”.)
Coefficient of the outdoor unit for indoor unit 2 (Outdoor temp. 26.6°F [−3°C] W.B., Indoor temp. 77.0°F [25°C] D.B.)
= 1.34 × 15/(15 + 18) + 1.09 × 18/(15 + 18)
= 1.20
n
k=1
n
k=1
Average indoor temp. power input coefficient ( c
ave
) = ∑ {c
k
× (M
k
/ ∑ M
k
)}
(4) Outdoor power input (PIo)
(3) Coefficient of the partial load (CTi)
Total indoor units capacity
15 + 18 = 33, thus, (CTi) = 0.9 (Refer to the tables in “9.STANDARD CAPACITY DIAGRAM”.)