Selection Procedure - Carrier Comfort 50EZ-A Product Data

SELECTION PROCEDURE (WITH EXAMPLE)
1. Determine cooling and heating requirements at
design conditions:
Given:
Required Cooling Capacity (TC)
Sensible Heat Capacity (SHC)
Required Heating Capacity . . . . . . . . . . . . . . .
Condenser Entering Air Temperature
Indoor- -Air Temperature 80°F (27°C) edb 67°F (19°C) ewb
Evaporator Air Quantity . . . . . . . . . . . . . . . . . .
External Static Pressure . . . . . . . . . . . . . . . .
Electrical Characteristics . . . . . . . . . . . . . . . . . . .
2. Select unit based on required cooling capacity.
Enter Net Cooling Capacities table at condenser entering
temperature of 95°F (35°C). Unit 036 at 1200 cfm and 67°F
(19°C) ewb (entering wet bulb) will provide a total capacity of
35,000 Btuh and a SHC of 26,200 Btuh. Calculate SHC correction,
if required, using Note 4 under Cooling Capacities tables.
3. Select heating capacity of unit to provide design
condition requirement.
In the Heating Capacities and Efficiencies table, note that the 36
size unit will deliver 35,000 BTUH at the ARI high temp rating
point. To achieve 60,000 BTUH, accessory electric heat will be
required. Use the Balance Point Worksheet to plot the load line
with the unit capacity. The difference between the load line and
unit capacity at the design heating temperature is the amount of
electric heat that will be required.
. . . . . . . . . . 34,500 Btuh
. . . . . . . . . . . . 26,000 Btuh
60,000 Btuh
. . . . . . . 95°F (35°C)
1200 CFM
0.200 IN.W.C.
208- -1- -60
4. Determine fan speed and power requirements at
design conditions.
Before entering the air delivery tables, calculate the total static
pressure required. From the given example, the Wet Coil Pressure
Drop Table, and the Filter Pressure Drop Table:
External Static Pressure
Filter
Wet Coil Pressure Drop
Total Static Pressure
Enter the table for Dry Coil Air Delivery— At 0.50 IN. W.C.
ESP (external static pressure) and MEDIUM speed the motor
delivers 1209 cfm.
5. Select unit that corresponds to power source
available.
The Electrical Data Table shows that the unit is designed to operate
at 208/230- -1- -60.
10
0.200 IN. W.C.
0.130 IN. W.C.
0.18 IN. W.C.
0.51 IN. W.C.