Refrigerant Cycle - Trane CGAM Installation & Operation Manual

CGAM Operating Principles

Refrigerant Cycle

Figure 84. CGAM refrigerant circuit
COMP 1B COMP 1A
The refrigeration cycle of the Model CGAM chiller is
conceptually similar to otherTrane air-cooled chiller
products.The CGAM chiller uses a brazed plate evaporator
and an air-cooled condenser.The compressors use suction
gas cooled motors and an oil management system to
provide almost oil-free refrigerant to the condenser and
evaporator for maximum heat transfer while lubricating
and sealing compressor bearings.The lubrication system
helps to assure long compressor life and contributes to
quiet operation.
Refrigerant condensers in the air-cooled heat exchanger
which is available in three configurations—slant, V and
W—based on the CGAM nominal tonnage cooling
capacity. Liquid refrigerant is metered into the brazed plate
evaporator using an electronic expansion valve to
maximize chiller efficiency at full and part load operation.
The CGAM chiller is equipped with a unit-mounted starter
and control panel. Microprocessor-based unit control
98
SCHRADER VALVE
P
T
SUCTION LINE
DISCHARGE LINE
T
SCHRADER VALVE
HPC P
SERVICE VALVE
BPHE
BALL VALVE
LIQUID LINE
Discharge temperature
sensor used:
1.) Low leaving temp
application without
partial heat recovery
option.
2.) Partial heat recovery
option with fan control
function.
modules (TraneTracer™CH530) provide accurate chilled
water control and provide monitoring, protection and
adaptive limit functions.The adaptive nature of the
controls intelligently prevent the chiller from operating
outside of its limits, or compensates for unusual operating
conditions while keeping the chiller running rather than
simply shutting off the chiller. If problems do occur, the
CH530 controls provide diagnostic messages to help the
operator in troubleshooting.
Refrigerant Cycle Description
The CGAM refrigeration cycle is described using the
pressure-enthalpy chart shown in
Points 1 through 5 are indicated on the chart. A schematic
showing refrigerant components throughout the system
is shown in Figure 85.
Refrigerant evaporation occurs in the brazed plate
evaporator. Metered refrigerant vaporizes as it cools the
chilled water or liquid flowing through the evaporator
SERVICE VALVE
ANGLE VALVE
FILTER & DRIER
SCHRADER VALVE
EXV
Figure 84 Key State
CG-SVX17E-EN