Compressed Air Circuit, Functional Description; Refrigerant System Component, Functional Description - Sullair ES-8 Operator's Manual And Parts List

2.4 COMPRESSED AIR CIRCUIT, FUNCTIONAL DE-
SCRIPTION
The compressed air drying circuit uses an air---to---
air heat exchanger which acts as a precooler/re---
heater, and an air---to---refrigerant heat exchanger
(evaporator).
Warm, saturated, compressed air first enters the
air---to---air heat exchanger, where it is precooled.
By precooling the incoming air, energy is saved
through the reduction of the heat load imposed on
the refrigerant compressor and condenser. From
the precooler, the air will enter into the evaporator
further reducing its temperature to 35_F to 39_F
(2_C to 4_C). Moisture is condensed, and it is then
separated by a cyclone separator and discharged
through an automatic float ---type drain trap.
The chilled air then re---enters the air---to---air heat
exchanger, where it is reheated. Reheating of the air
does not affect the air's dewpoint. It prevents con-
densation of moisture on the outside of the air---dis-
tribution piping. The cold air flow through the air---
to---air heat exchanger is in a direction opposite to
the flow of the warm, saturated incoming air. This
counterflow assures high temperature differential
throughout the heat exchanger, resulting in a more
effective heat transfer.
The compressed air leaving the compressor/dryer
then passes through an MPF filter which removes
particles down to 1 micron diameter, including co-
alesced liquid water and oil. The coalesced oil/wa-
ter mixture is discharged through an automatic
float---type drain trap.
2.5 REFRIGERANT SYSTEM COMPONENT, FUNC-
TIONAL DESCRIPTION
The refrigerant compressor compresses low pres-
sure refrigerant gas into high pressure refrigerant
gas.
The air---cooled condenser changes high pressure
refrigerant gas from compressor discharge into
high pressure liquid as the gas flows through.
The filter/dryer removes any contaminant and
moisture that may be in the system.
The capillary tube is a non---adjustable metering
device which separates the high pressure side of
the system from the low pressure side. The capillary
tube controls the flow of refrigerant to the evapora-
tor in order to maintain a non---adjustable tempera-
ture difference (superheat) between the evaporator
refrigerant inlet and outlet (see Figure
The hot gas bypass valve (HGBV) is used to artifi-
cially load the evaporator during part ---load condi-
tions. The HGBV accomplishes this task by divert-
ing high pressure gas from the compressor dis-
charge to the inlet of the evaporator. The HGBV sep-
arates the high pressure side of the system from the
low pressure side. The HGBV will modulate from ful-
ly open to fully closed in response to its outlet pres-
sure setting. The HGBV is set to maintain the mini-
mum allowable suction line pressure.
The refrigerant-- to -- air heat exchanger chills the
compressed air to achieve a 35_F to 39_F (2_C to
4_C) temperature. A low pressure liquid/gas mix-
ture enters the refrigerant side of the heat exchang-
er and removes heat from the warm compressed air.
The refrigerant changes phases as it passes
through the heat exchanger and exits as a low pres-
sure superheated gas.
Section 2
DESCRIPTION
2 --- 2).
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