Trane TSC060-120 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 theTrane calculation methods or any other standard accepted method.

Factors used in unit selection:

A

Total Cooling Load: 59 MBh

B

Sensible Cooling Load: 40 MBh

C

Airflow: 2000 cfm

D

Electrical Characteristics: 380-415/50/3

E

Summer Design Conditions: Entering

Evaporator Coil: 80 DB, 67 WB Outdoor

Ambient: 95

F

External Static Pressure: 0.45 in. wg

Step 2

Table PD-1a shows that aTSC060AD has a gross cooling capacity of 62.0 MBh and

46.4MBh sensible capacity at 2000 cfm and 95 DB outdoor ambient with 80 DB, 67 WB air entering the evaporator.

To Find Capacity at Intermediate Conditions Not in the Table

When the design conditions are between two numbers that are in the capacity table, interpolation is required to approximate the capacity. Note: Extrapolation outside of the table conditions is not recommended.

Step 3

In order to select the correct unit which meets the building’s requirements, the fan motor heat must be deducted from the gross cooling capacity.The amount of heat that the fan motor generates is dependent on the effort by the motor - cfm and static pressure.To determine the total unit static pressure:

External Static (duct system)

	0.45 wg
Standard Filter 1 in.	0.15 wg
from Table PD-21a
Economizer	0.02 wg
(100% Return Air)	from
Table PD-21a
Electric Heater Size 26 MBh	0.07 wg
from Table PD-21a
Total Static Pressure	0.69 wg

Note: The Evaporator Fan Performance Table PD-6a has deducted the pressure drop for a 1 in. filter already in the unit (see note below Table PD-6a). Therefore, the actual total static pressure is 0.69 - 0.15 (fromTable PD-21a) = 0.50 wg.

With 2000 cfm and 0.50 wg.

Table PD-6a shows .83 bhp for this unit. 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 0.83 + 0.451 = 2.87 MBh

Now subtract the fan motor heat from the gross cooling capacity of the unit: Net Total Cooling Capacity

= 62 MBh - 2.87 = 59.1 MBh.

Net Sensible Cooling Capacity = 46.4 MBh - 2.87 = 43.5 MBh.

Step 5

If the performance will not meet the required load of the building’s total or sensible cooling load, try a selection at the next higher size unit.

Heating Capacity

Step 1

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

Step 2

Size the system heating capacity to match the calculated building heating load. The following are building heating requirements:

A

Total heating load of 15 MBH

B

2000 cfm

C

380 volt/3 phase Power Supply

The electric heat accessory capacities are listed inTable PD-23a. From the table, the smallest heater will deliver 26 MBh at 380 volts. Referring toTable ED-2, the electric heater accessory selection is BAYHTRR412A.

Air Delivery Selection

External static pressure drop through the air distribution system has been calculated to be 0.45 inches of water. FromTable PD-21a static pressure drop through the economizer is 0.02 and the 26 kW heater is 0.07 inches of water (0.45

+0.02 + 0.07). EnterTable PD-6a for a TSC060AD at 2000 cfm and 0.54 static pressure. The standard motor will give the desired airflow at a rated bhp of about 1.01.

Accessory Selection

Select accessories needed to accommodate the application.

RT-PRC016-EN 11