Selection procedure 50XCA08 unit example

24 (TYP)

a50-8502

SERVICE CLEARANCE	36

NOTE: Dimensions are in inches.

Selection procedure (50XCA08 unit example)

IDetermine design conditions. Given:

Cooling Requirements

Total Cooling Capacity (TC) . . . . . . . . .82,000 Btuh

Sensible Cooling Capacity (SHC) . . . . .65,000 Btuh

Evaporator Air Quantity. . . . . . . . . . . . . 3,000 Cfm

Condenser Air Quantity . . . . . . . . . . . . . 3,500 Cfm

Summer Entering-Air Conditions:

Entering dry bulb (edb) . . . . . . . . . . . . . . . . .80 F

Entering wet bulb (ewb) . . . . . . . . . . . . . . . .67 F

Entering Condenser Air Temp (EAT) . . . . . . .95 F

Unit Voltage . . . . . . . . . . . . . . . . . . . . . . . . 460 V

Fan Requirements

External Static Pressure Required

ESP (in. wg) . . . . . . . . . . . . . . . . . . . . . . . . . .0.75

IISelect unit based on cooling requirements.

Enter Gross Cooling Capacities table for 50XCA08 unit at 3000 cfm and required wet bulb of 67 F and read down to the section displaying capacities with 95 F entering-air temperature. The 50XCA08 pro- vides a total capacity closest to design requirements.

For example:

Unit selection — 50XCA08

Selected at 3000 cfm of 80 F edb, 67 F ewb enter- ing air.

TC = 83,800 Btuh

SHC = 66,500 Btuh

(See correction factor table, below the cooling capacity tables.)

Compressor — Power Input = 5.85 kW

Leaving Air db = 59.9 F

Leaving Air wb at 67 F wb

=58.3 F

IIIFan requirements.

External static pressure (ESP) required 0.75 in. wg

Enter Evaporator Fan Performance table for cfm, and static pressure required to obtain the following data:

For 3000 cfm and 0.75 ESP, by interpolation the fan operates at 877 rpm and requires 0.98 brake horsepower.

Since standard motor horsepower is 1.0, it will pro- duce the necessary cfm and ESP for this job.