14
PERFORMANCE DATA (CONT)
Multiplication Factors
Heater kW Rating
Voltage Distribution V/3/60
Multiplication Factor
240
200
.69
208
.75
230
.92
240
1.00
Example: 15.0 kW (at 240v) heater on 208v
= 15.0 (.75 mult factor)
= 11.25 capacity at 208v
LEGEND
BF
— Bypass Factor
edb — Entering Dry---Bulb
Ewb — Entering Wet---Bulb
kW — Total Unit Power Input
ldb — Leaving Dry---Bulb
lwb — Leaving Wet---Bulb
SHC — Sensible Heat Capacity (1000 Btuh)
TC
— Total Capacity (1000 Btuh) (net)
*At 75
°
F entering dry bulb (Tennessee Valley Authority [TVA] rating condi-
tions); all other at 80
°
F entering dry bulb.
COOLING NOTES:
1. Ratings are net; they account for the effects of the evaporator fan motor
power and heat.
2. Direct interpolation is permissible. Do not extrapolate.
3. The following formulas may be used:
Sensible capacity (Btuh)
1.10 x cfm
t
ldb =
t
edb
---
Wet---bulb temperature corresponding to enthalpy
air leaving evaporator coil (
h
lwb)
t
lwb =
total capacity (Btuh)
4.5 x cfm
h
lwb =
h
ewb ---
Where:
h
ewb = Enthalpy of air entering evaporator coil
4. The SHC is based on 80
°
F edb temperature of air entering evaporator coil.
Below 80
°
F edb, subtract (corr factor x cfm) from SHC.
Above 80
°
F edb, add (corr factor x cfm) to SHC.
Correction Factor = 1.10 x (1 + BF) x (edb + 80).
5. Integrated capacity is maximum (instantaneous) capacity less the effect of
frost on the outdoor coil and the heat required to defrost it.
704C