17
PERFORMANCE DATA (CONT)
ECONOMIZER 1---IN. FILTER PRESSURE DROP (IN. WC)
UNIT 50SZ
PRESSURE DROP
024--030
0.20
036--060
0.25
MULTIPLICATION FACTORS
HEATER kW RATING
VOLTAGE DISTRIBUTION
V/3/60
MULTIPLICATION FACTOR
240
200
208
230
240
.69
.75
.92
1.00
Exaqmple: 20 kW (at 240v) heater on 230v
= 20.0 (.92 mult factor)
= 18.4 kW capacity at 230v
LEGEND
BF— Bypass Factor
edb— Entering Dry---Bulb
Ewb — Entering Wet---Bulb
kW — Total Unit Power Input
SHC — Sensible Heat Capacity (1000 Btuh)
TC — Total Capacity (1000 Btuh) (net)
rh — Relative Humidity
Shading indicates Integrated Ratings
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 (26.6
_
C) edb, subtract (corr factor x cfm) from SHC.
Above 80
_
F (26.6
_
C) 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 oudoor coil and
the heat required to defrost it.
50SZ
