Carrier 50HS, Данные о продукции

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Selection procedure
I Determine cooling and heating requirements at
design conditions.
Given:
Required Cooling Capacity (TC) . . . . . 28,000 Btuh
Sensible Heat Capacity (SHC) . . . . . . 20,500 Btuh
Required Heating Capacity . . . . . . . . . 28,550 Btuh
Outdoor Entering-Air Temperature . . . . . . . . . 95 F
Outdoor-Air Winter Design Temperature . . . . . 20 F
Indoor-Air Winter Design Temperature . . . . . . 70 F
Indoor Entering-Air Temperature . . . . . . . 80 F edb,
67 F ewb
Indoor-Air Quantity . . . . . . . . . . . . . . . . 1125 cfm
External Static Pressure . . . . . . . . . . . . 0.40 in. wg
Electrical Characteristics (V-Ph-Hz) . . . . . . 230-1-60
edb — entering dry bulb
ewb — entering wet bulb
II Select unit based on required cooling capacity.
Enter Cooling Capacities table at outdoor entering-air
temperature of 95 F, indoor air entering at 1125 cfm
and 67 F ewb (entering wet bulb). The 50HS030 unit
will provide a total cooling capacity of 29,300 Btuh
and a sensible heat capacity of 22,100 Btuh.
For indoor-air temperature other than 80 F edb (en-
tering dry bulb), calculate sensible heat capacity cor-
rection, as required, using the formula found in
Note 3 following the cooling capacities tables.
NOTE: Unit ratings are net capacities.
III Select electric heat.
Enter the unit 50HS030 Heating Capacities table at
1125 cfm. At 70 F return indoor air and 20 F air en-
tering outdoor coil, the integrated heating capacity is
14,900 Btuh. (Select integrated heating capacity value
since deductions for outdoor-coil frost and defrosting
have already been made. No correction is required.)
The required heating capacity is 28,550 Btuh. There-
fore, 13,650 Btuh (28,550 – 14,900) additional elec-
tric heat is required.
Determine additional electric heat capacity in kW.
13,650 Btuh
= 4.0 kW of heat required
3414 Btuh/kW
Enter the Electric Heater Packages table on page 19
for 208/240 v, single-phase, 50HS030 unit. The 5-kW
heater at 240 v most closely satisfies the heating re-
quired. To calculate kW at 230 v, multiply the heater
kW by multiplication factor 0.92 found in the Multipli-
cation Factors table on page 21.
5 kW x 0.92 = 4.6 kW
4.6 x 3414 = 15,704 Btuh
To calculate kW at 208 v, see Electric Heater Pack-
ages table on page 19.
Total unit heating capacity is 30,604 Btuh (14,900
+ 15,704).
IV Determine fan speed and power requirements
at design conditions.
Before entering the air delivery tables, calculate the
total static pressure required. From the given, the Ac-
cessory Electric Heat Pressure Drop table, Wet Coil
Pressure Drop table, and the Filter Pressure Drop table,
find:
External static pressure
0.40 in. wg
Filter 0.11 in. wg
Electric heat 0.04 in. wg
Wet coil 0.11 in. wg
Total static pressure 0.66 in. wg
Enter the table for Dry Coil Air Delivery — Hori-
zontal Discharge at 1125 cfm and 230-v high speed.
By interpolation, the standard motor will deliver
0.66 in. wg static pressure. This will adequately handle
job requirements.
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