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FAXA-SVX01B-EN
Operation
general
information
Evaporator 2
Evaporator 1
Circuit 2 Compressors
Circuit 1 Compressor
Subcooler
Condenser 1
Condenser 2
FAU Without Reheat
Figure O-GI-10 shows the Packaged FAU
DX system, using a refrigerant circuit
design without reheat.
Dehumidification (Drying)
Consider Figure O-GI-8. If the outdoor air
dew point or zone RH is above the drying
setpoint, the FAU will dehumidify the
outdoor air. 100% outdoor air enters the
FAU (h1). The unit filters, cools (h2) and
dehumidifies the air as it is drawn through
the evaporator coils. Air leaves the
evaporator coils saturated at a preset dew
point setpoint (h3). Since the dew point
setpoint is fully adjustable, the desired
dew point condition is maintained at all
load conditions.
Cooling or Heating
Consider Chart O-GI-9. If the outdoor air
dew point is equal to or below the dew
point setpoint, the FAU will heat or cool
the outdoor air to separate and adjust
cooling or heating setpoints. 100%
outdoor air enters the FAU (t1). The unit
filters and cools or heats the air as it is
drawn through the evaporators and
heating section. The air leaves the FAU at
the cooling or heating setpoint and equal
to or below the dew point setpoint.
FIgure O-GI-10. Refrigeration system diagram without reheat
Chart O-GI-8. Psychrometric chart with
dehumidification, no reheat
Chart O-GI-9. Psychrometric chart with
cooling and heating only
Dry Bulb Temperature
Dewpoint Temperature
Wet Bulb Temperature
Dehumidification
h1
h2
h3
Dry Bulb Temperature
Dewpoint T
e
mperature
W
et Bulb T
emperature
t3
t4
heating
t1
t2
cooling
Summary of Contents for FADA
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