Trane CVGF - Manual (Page 20)

CTV-PRC001-GB 2 0
The Trane CVGF packaged centrifugal
water chillers using HFC-134a
refrigerant consist of a hermetic two
stage, gear-drive centrifugal
compressor, evaporator, condenser,
interstage economizer, unit-mounted
microprocessor based control panel
and compressor motor starter. The
chiller is completely factory assembled.
Compressor
Two-stage centrifugal compressor with
high-strength aluminum alloy fully
shrouded impellers. The impellers are
tested at 25 percent over design
operating speed. The rotating
assembly is dynamically balanced for
vibration of less than 5.1 mm/s (0.2 ips
peak velocities) at nominal operating
speeds. The control system affords
100 - 20 percent capacity modulation
by electrically actuated guide vanes
upstream of each impeller.
Drive Train
The drive train consists of helical bull
and pinion gears. Gear tooth surfaces
are case hardened and precision
ground. The one-piece impeller shaft is
supported by hydrodynamic thrust and
radial bearings.
Motor
The motor is a hermetic, liquid
refrigerant cooled, two-pole, low-slip
squirrel cage induction motor. A radial
hydrodynamic bearing and duplex
angular contact ball bearings support
the rotor assembly. Winding-
embedded sensors provide positive
thermal protection.
Lubrication System
The lubrication system consists of an
internal oil sump with heaters, positive
displacement oil pump, brazed plate
condenser-cooled oil cooler, and oil
distillation/return line.
Economizer/Orifice
The economizer consists of a carbon
steel shell with internal components
designed to prevent liquid carryover to
the compressor. Liquid refrigerant is
admitted through a single calibrated
orifice (no moving parts) which
maintains a pressure differential
between condenser and economizer.
Evaporator
The evaporator is designed, tested and
stamped in accordance with ASME
Boiler and Pressure Vessel Code or PED
(European Code) for refrigerant side
working pressure of 15.2 bars (220
psig). It consists of a carbon steel shell
Mechanical
Specifications
with steel tube sheets welded to each
end. Intermediate tube support sheets
positioned along the shell axis prevent
relative tube motion. Individually
replaceable externally finned and
internally grooved 19 mm (¾ in.) and
25.4 mm (1.0 in.) nominal diameter
seamless copper tubes are
mechanically expanded into tube
sheets.
Two or three pass water boxes rated at
10.5 bar (150 psi) is standard. Grooved
pipe stubs for Victaulic couplings are
standard; flanged connections are
optionally available. The waterside is
hydrostatically tested at 1.5 times
maximum working pressure.
Liquid refrigerant is admitted to the
evaporator through a single calibrated
orifice (no moving parts) which
maintains a pressure differential
between the economizer and the
evaporator.
Condenser
The condenser is designed, tested and
stamped in accordance with the ASME
Boiler and Pressure Vessel Code or PED
(European Code) for a refrigerant side
working pressure of 15.2 bars (220
psig). It consists of a carbon steel shell
with steel tube sheets welded to each
end. Individually replaceable, externally
finned and internally grooved 19 mm
(¾ in.) and 25.4 mm (1.0 in.) nominal
diameter seamless copper tubes are
mechanically expanded into the tube
sheets.