9. Selection procedure
Single Package
22
_ 50Hz, R410A
Single Package
Selection Procedure
Heating
Step 4.
The capacity estimated at step #3 is the gross capacity of the selected unit. The generated heat
from indoor motor is a function of l/s & static pressure. To determine the total unit static pressure.
Evaporator fan motor performance table has deducted the pressure drop for filter already in the unit.
Therefore, the actual total static pressure is 17.78 mm Aq.
(When installing the economizer to the product, it should be added pressure drop of Economizer
Fresh Damper (OA) 10% to total static pressure.)
With 3,776 l/s and 17.78 mm Aq., Evaporator Fan Performance EK-H2408C02 (SI) table shows 2.68
BkW for this unit.
FAN MOTOR HEAT;
1.22 x Fan Bkw = kW
1.22 x 2.68 = 3.27kW
Now subtract the fan motor heat from the gross cooling capacity of the unit;
Step 5.
If the selected unit performance will not meet the required load, either total or sensible cooling, the
next higher size unit should be selected.
Step 1.
Calculate the building heating load using the ASHRAE calculation or from other standard accepted
method.
Step 2.
From Heating Capacity EK-H2408C02 (SI) table, The heating capacity is 69.7 kW at 3,776 l/s with
4°C outdoor temperature and 20°C indoor temperature. The required heating capacity is 58.6kW.
Since heating capacity 69.7kW is greater than required heating capacity 58.6kW. So, additional elec-
tric heat is not required.
Step 3.
If the selected unit performance will not meet the required load. The additional electric heater should
be selected from Electric Heating Capacity table.
Net cooling capacity
69.1kW - 2.68 kW = 66.42 kW
Net sensible cooling
54.6kW - 2.68 kW = 51.92 kW
External Static(Duct system)
17.78 mm Aq.
Standard Filter
2.54 mm Aq.
Economizer Fresh Damper (OA) 10%
Refer to the economizer applied models.
(From table Accessory Static Pressure Drops)
Total static pressure
20.32 mm Aq.