Method Of Capacity Calculation - Fujitsu Airstage J-II Series Design & Technical Manual

3-2. METHOD OF CAPACITY CALCULATION

The capacity calculation method which takes the effects of air temperature, pipe length and
frosting/defrosting into consideration is shown below.
1. Calculate the estimated capacity of each indoor unit.
(1) Find capacity of indoor unit at rated condition (TCin)r and at design temperature (TCin)d
[from 7. CAPACITY TABLE COOLING (INDOOR UNIT) or 8. CAPACITY TABLE HEATING (INDOOR UNIT)]
(2) Find the following compensation coefficient
● Compensation coefficient of pipe length
„
● Compensation coefficient of frosting/defrosting (Heating calculation only
„
(3) Calculate the estimated capacity of indoor unit (TCin)e.
COOLING:
Estimated capacity of indoor unit (TCin)e
= Capacity of indoor unit at design temperature (TCin)d
x Compensation coefficient of pipe length
HEATING:
Estimated capacity of indoor unit (TCin)e
= Capacity of indoor unit at design temperature (TCin)d
x Compensation coefficient of pipe length
x Compensation coefficient of frosting/defrosting
2. Calculate the compensated capacity of outdoor unit.
(4) Find capacity of outdoor unit at rated condition (TCout)r
(5) Calculate total rated capacity of indoor units
and ratio to the rated capacity of outdoor unit : ∑(TCin)r / (TCout)r .
(6) Find capacity of outdoor unit at design temperature (TCout)d
[using result of (5) and 4. CAPACITY TABLE (OUTDOOR UNIT)].
(7) Calculate the compensated capacity of outdoor unit (TCout)c.
COOLING:
Compensated capacity of outdoor unit (TCout)c
= Capacity of outdoor unit at design temperature (TCout)d
x Compensation coefficient of pipe length
HEATING:
Compensated capacity of outdoor unit (TCout)c
= Capacity of outdoor unit at design temperature (TCout)d
x Compensation coefficient of pipe length
x Compensation coefficient of frosting/defrosting
3. Decide system capacity.
(8) Calculate total capacity of indoor units at design temperature ∑(TCin)d.
(9) System capacity = the smaller one of (TCout)c and ∑(TCin)d. • • • • • • • • (7) or (8)
4. Calculate actual capacity of each indoor unit.
(10) Calculate actual capacity of each indoor unit by dividing system capacity proportionally.
Actual capacity of indoor unit
[From 6. CAPACITY COMPENSATION COEFFICIENT].
: ∑(TCin)r
= (System capacity) x (Rated capacity of indoor unit) / (Total rated
capacity of indoor unit )
= (System capacity) x (TCin)r / ∑(TCin)r • • • • • (9) x (1) / (5)
- (02 - 09) -
)
[From 2. MODEL LINE UP].