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11 - MAJOR SYSTEM COMPONENTS AND OPERATION DATA
11.1 - MagLev centrifugal compressor
- 19PV units use TT (Twin-Turbine) MagLev centrifugal
compressors equipped with an inlet guide valve and
controlled by a speed variator.
- Compressor capacity control is ensured by successive use
of speed variation (using a frequency variator) and swept
volume variation at the turbine (using the Inlet Guide Valve).
- The combination of these two control modes permits fine
control of the unit capacity between 15% and 100%.
- The MagLev centrifugal compressor models used are: TT300,
TT350
- The MagLev centrifugal compressors are NOT lubrificated
- The compressor drive and the compressor motor are cooled
by a liquid line. The cooling system is controlled by two valves
located in the compressor drive.
11.1.1 - Refrigerant
The 19PV is a liquid chiller operating only with refrigerant R-134a.
11.1.2 - Capacity control system
19PV units are equipped with a frequency variator that permits
compressor capacity adjustment by varying the motor speed. The
frequency range depends on the refrigerant pressure ratio. At the
minimum speed, the compressor reduces the capacity by closing
the inlet guide valve.
The compressor drive uses power supply waveform generation
with variable frequency and voltage, generated by pulse width
modulation (PWM).
Compressor start-up and stopping and the frequency setting for
the operating range is only by RS485 communication in the
MODBUS protocol via the controller.
11.1.3 - Suction valve (Option 92)
An isolating valve can be added to ease maintenance on
compressor. This valve can be moved ONLY without pressure
differential upstream and downstream of this valve.
The following markers indicate the fully opened position and the
fully closed position of the valve.
Opened position
11.1.4 - Line reactor
A line reactor is a special form of inductor that is typically used
between the line and the load to smooth current inrush, reduce
harmonics and noise, and buffer the systems connected to it.
Specifically it is an inductor that adds inductive impedance to a
circuit
One Line reactor by compressor is mandatory and they are located
in the electrical box.
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11.1.5 - EMC Filter
The EMC filter reduces electrical noise on the power lines
(conducted emissions), it is located close to the compressor to
reduce broadcasting of the noise (radiated emissions) from the
power lines themselves.
11.1.6 - Fast acting fuses
All compressors are fitted with class T fast acting fuses to protect
the solid state inverter.
The fuses are included in the TT300 compressor under the main
cover. With the TT350 compressor, the fast acting fuses are located
in the electrical box.
11.2 - Pressure vessels
General
Monitoring during operation, re-qualification, re-testing and re-
testing dispensation:
Repair
Any repair or modification, including the replacement of moving
parts:
Closed position
Recycling
The unit is wholly or partly recyclable. After use it contains
refrigerant vapours. It is coated by paint.
Operating life
The evaporator is designed for:
- Follow the regulations on monitoring pressurised equipment.
- It is normally required that the user or operator sets up and
maintains a monitoring and maintenance file.
- If no regulations exist or to complement regulations, follow
the control programmes of EN 378.
- If they exist follow local professional recommendations.
- Regularly inspect the condition of the coating (paint) to detect
blistering resulting from corrosion. To do this, check a non-
insulated section of the container or the rust formation at the
insulation joints.
- Regularly check for possible presence of impurities (e.g.
silicon grains) in the heat exchange fluids. These impurities
maybe the cause of the wear or corrosion by puncture.
- Filter the heat exchange fluid check and carry out internal
inspections as described in EN 378.
- In case of re-testing please refer to the maximum operating
pressure given on the unit nameplate.
- The reports of periodical checks by the user or operator must
be included in the supervision and maintenance file.
- must follow local regulations and be made by qualified
operators and in accordance with qualified procedures,
including changing the heat exchanger tubes.
- must be made in accordance with the instructions of the original
manufacturer. Repair and modification that necessitate
permanent assembly (soldering, welding, expanding etc.)
must be made using the correct procedures and by qualified
operators.
- An indication of any modification or repair must be shown in
the monitoring and maintenance file.
- prolonged storage of 15 years under nitrogen charge with a
temperature difference of 20 K per day.
- 452000 cycles (start-ups) with a maximum difference of 6 K
between two neighbouring points in the vessel, based on 6
start-ups per hour over 15 years at a usage rate of 57%.
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