c.
Refrigerant dryer and suction line strainer.
d.
Air-cooled condenser, with condenser fan and motor.
2.4.3
Instrumentation and Control
Include control panel in dryer cabinet containing:
a.
Indicators for the Following Services: Inlet air pressure gage,
discharge air pressure gage, inlet air temperature gage, main
exchanger temperature gage, refrigeration compressor suction
pressure gage, refrigeration compressor discharge pressure gage,
green "Power On" light, power interruption light, and high
temperature light.
b.
Electrical Relays: Locate in an enclosed portion of the panel,
accessible for ease of servicing.
c.
Controls and Interlocks: To maintain required compressed air dew
point and to cycle air-cooled condenser with refrigeration
compressor [while maintaining head pressure control with low
ambient temperature].
2.5
LOW PRESSURE COMPRESSED AIR DRYER (CHILLED WATER TYPE)
**************************************************************************
NOTE: Chilled water air dryers are usually provided
for 944 scms 2000 scfm and larger capacities.
CAUTION: Specify correct system pressure. If the
specification is edited to use a dryer with direct
heat exchange between air and refrigerant, assure
that the air is not used for breathing since
refrigerant leakage into the compressed air may be
hazardous to personnel; warning signs may be
required.
**************************************************************************
Provide low pressure compressed air dryer of the mechanical refrigerator
type, with closed chilled water system, regenerative air to air exchanger,
and main compressed air to water heat exchanger. Refrigeration system
shall produce chilled water which, in turn, circulates through air-water
exchanger to dry the air. Provide internal tubing, wiring and piping
complete, such that only connections to air inlet and outlet, to pump
contactor, to refrigerant compressor contactor, to condensate drain, and to
air cooled condenser need be provided. Dryer shall be suitable for a
compressed air operating pressure of 862 kPa (gage) 125 psig, with air
leaving temperature of [_____] degrees C F and dew point of [_____] degrees
C F at rated pressure.
2.5.1
Air Circuit
a.
Regenerative Heat Exchanger: Air to air exchanger, with inlet air
passing through tubes and outlet air in shell, designed to reduce
cooling load at design conditions by precooling inlet air minus 7
degrees C 20 degrees F.
b.
Main Heat Exchanger: Shell and tube construction, single-pass,
with air in tubes and water in shell, designed for minimum air
pressure drop, flanged connections, tubes rolled into tube sheets,
SECTION 15211N
Page 18
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