KT-230-2
12
the overall efficiency of the system: Suction gas super-
heating and the difference between condensing and
suction-gas pressures should be kept as low as pos-
sible within the application limits. Ensure the minimum
necessary suction gas overheating.
Observe these points when planning the system:
• Keep pipe sections short.
• Keep pressure loss in all components as low as pos-
sible.
• Keep the temperature difference as low as possible:
– Ensure low icing of the evaporator.
– Keep condensers clean.
• Keep condensing temperature low in a controlled
manner.
4.6.1
Minimum equipment for the RI system
The RI system does not require any compressor equip-
ment other than the CM-RC-01. An additional fan is not
necessary. However, it allows operation in a larger
range. See BITZER SOFTWAREfor application limits.
4.6.2
Integrating the RI system into the
refrigeration circuit
TC
CM-RC
1
2
3: Ø10 mm (3/8")
4
5
Fig. 5: Refrigeration circuit with RI system
1
Compressor with CM-RC-01, RI injection valve,
discharge gas temperature sensor and optional
additional fan
2
RI injection valve
3
Pipeline between liquid line and RI injection
valve
4
Filter dryer
5
Sight glass
➙ The RI system requires an additional pipe (3).
• Install the pipe from the liquid line to the RI injection
valve (2) on the compressor (1), diam. 10 mm or
3/8".
• First guide this pipeline downwards from a horizontal
section of the liquid line. This ensures a bubble-free
liquid supply.
• Install filter dryer (4). This protects the RI injection
valve and the compressor.
• Sight glass (5) can also be installed. This can be
used to visually check whether the liquid refrigerant
is bubble free.
• Insulate the suction gas line.
5
Operating and monitoring functions
5.1
Operating functions
This chapter describes all operating functions, including
those that are optional and those that are not available
with every compressor design.
5.1.1
CRII capacity control
The CM-RC-01 adjusts the capacity of the compressor
quasi-steplessly according to the setpoint of the higher-
level system controller. To do this, it switches the CRII
solenoid valves.
Compressors, each cylinder bank of which is equipped
with a CRII capacity regulator, are thus controlled
between full load and 10% part load. These are 4-cylin-
der compressors with two installed capacity regulators
and 6-cylinder compressors with three.
8-cylinder compressors can be equipped with a max-
imum of two capacity regulators. Their control range is
then between full load and 50%.
Compressors for transcritical CO
2
applications can be
equipped with a maximum of 2 capacity regulators. The
4-cylinder models can be controlled between full load
and 10% part load, the 6-cylinder models between full
load and 33% part load.
