Selection Procedure; Cooling Capacity; Heating Capacity; Air Delivery Selection - Trane Voyager Manual

Selection
Procedure

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.
Example: The following are the
building cooling requirements:
a. Electrical Characteristics: 460/60/3
b. Summer Design Conditions:
Entering Evaporator Coil: 80° DB/
67° WB
Outdoor Ambient: 95°
c. Total Cooling Load: 60 MBh
d. Sensible Cooling Load: 40 MBh
e. Airflow: 2000 cfm External Static
Pressure: .5 in wg
Step 2 — Size the equipment using
Table 25-1 to match the cooling loads
at design conditions.
Table 25-1 shows that a YCD060C4
has a gross cooling capacity of 62.5
MBh and 43.7 MBh sensible capacity
at 95 DB ambient and 2000 cfm with
80 DB/ 67 WB air entering the
evaporator.
To find the net cooling capacities, fan
motor heat must be subtracted. For
practical purposes, we suggest
multiplying the operating fan motor
horsepower by 4.39.
For example: With 2000 cfm and 0.50
inches, specified by the engineer,
Table 38-1 shows .60 bhp for a low
heat model. Note below the table
gives a formula to calculate Fan Motor
Heat, 4.39 X 0.60 = 2.6 MBh.
Net Total Cooling Capacity =
62.6 MBh - 2.6 = 60.0 MBh
Net Sensible Cooling Capacity =
43.7 MBh - 2.6 = 41.1 MBh.
22

Heating Capacity

Step 1 — Calculate the building
heating load using the Trane calcula-
tion 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 70.0 MBh
b. 2000 cfm
c. Fuel - Natural gas
For the YCD060C4, there are two
heating capacities available, 90 MBh
and 135 MBh input models shown in
Table 54-1. The output capacities of
these furnaces are 73.0 MBh and 109
MBh respectively. The low heat model
with 73.0 MBh best matches the
building requirements, indicating a
YCD060C4L should be selected.

Air Delivery Selection

External static pressure drop through
the air distribution system has been
calculated to be 0.5 inches of water.
Enter Table 38-1 for a YCD060C4L at
2000 cfm and 0.50 static pressure.
The standard motor at high speed will
give the desired airflow.
Accessory Selection
Select accessories needed to
accommodate the application.