Trane WSC060-120 manual Selection Procedure IP Units

Selection Procedure - IP Units

Cooling Capacity

Step 1

Calculate the building’s total and sensible cooling loads at design conditions. Use the Trane calculation form or any other standard accepted method.

Step 2

Size the equipment usingTable PD-1a. Match the cooling loads at design conditions.

Example: The following are the building cooling requirements:

A

Electrical Characteristics: 380–415/50/3

B

Summer Design Conditions:

Entering Evaporator Coil: 80 DB/ 67 WB

Outdoor Ambient: 95

C

Total Cooling Load: 53 MBh

D

Sensible Cooling Load: 33 MBh

E

Airflow: 2,000 cfm

External Static Pressure: .52 in. w.g.

F

Downflow Configuration

Table PD-1a shows that a WSC060AD has a gross cooling capacity of 59.0 MBh and 45.7 MBh sensible capacity at 95 degree ambient and 2,000 cfm with 80 DB/67 WB air entering the evaporator.

To find the net cooling capacities, fan motor heat must be subtracted. Determine the total unit static pressure:

External Static	0.52 in.
Standard Filter 1 in.	0.15 in.
Economizer	0.18 in.
Supplementary Electric Heat	0.083 in.
Total Static Pressure	0.933 in.

Note: The Evaporator Fan Performance Table PD-9a has deducted the pressure drop for a 1 in. filter already in the downflow unit.

Therefore, the actualTotal Static Pressure is 0.933 – 0.15 = 0.78. With 2,000 cfm and 0.78 inches,Table PD-9a shows 1.00 bhp.

Note below the table gives a formula to calculate Fan Motor Heat,

Fan Motor Heat (MBh) = 2.915 x (Fan bhp) + 0.451

= 2.915 x 1.00 + 0.451 = 3.37 MBh

NetTotal Cooling Capacity =

57 – 3.37 = 53.6 MBh

Net Sensible Cooling Capacity =

38 – 3.37 = 34.6 MBh

Heating Capacity

Step 1

Calculate the building heating load using theTrane calculation form or other standard accepted method.

Step 2

Size the equipment usingTable PD-5a to match the heating loads at design conditions.

A

Total Heating Load: 50 MBh

B

Outdoor Ambient (Winter) 17 DB

C

Indoor Return Temperature: 70 DB

D

Airflow: 2,000 cfm

Use the portion ofTable PD-5a for the WSC060AD to determine capacity at winter design conditions. The mechanical heating portion of the heat pump will provide 29.1 MBh.

Step 3

Because 29.1 MBh is less than the building’s required heating capacity at winter design conditions, a supplementary heater must be selected.

50 MBh – 29.1 MBh = 29.9 MBh

FromTable PD-9a, at 380 volts, the 38.0 MBh Heater will be adequate to do the job.

10.9 kW 38.0 MBh

FromTable ED-2 select heater BAYHTRR418A (38.0 MBh at 380 volts).

Air Delivery Selection

External static pressure drop through the air distribution system has been calculated to be 0.80 inches of water. EnterTable PD-9a for a WSC060AD at 2000 cfm and 0.80 static pressure. The standard motor will give the desired airflow.

Accessory Selection

Select accessories needed to accommodate the application.

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