User Guide
|
Capacity Controller, AK-PC 651
RS8HA102 | 3
© Danfoss | ADAP-KOOL® | 2015.10
Suction Group
Compressor types
The following types of compressor combinations can be used for
regulation:
• Several single-step compressors
• One speed controlled comp single-step compressors or
multi -step compressors
• One Digital scroll comp single-step compressors or multi
-step compressors
• One Copeland Stream Compressor (4 or 6 cylinders) + single-step
or multi-step compressors
• Bitzer CRII compressor (4 or 6 cylinders) + single-step or multi-
step compressors
• One multi-step comp single-step compressors
• Several multi-step compressors with the same number
of unloaders
In the combinations where the first compressor is different from
the others, it may be of a different size than the subsequent
single-stage compressors.
Capacity regulation
The cut-in capacity is controlled by signals from the connected
pressure transmitter/temperature sensor and the set reference.
Set a neutral zone around the reference .
In the neutral zone, the regulating compressor controls the
capacity so that pressure can be maintained. When it can no
longer maintain the pressure within the neutral zone, the control-
ler will cut out or cut in the next compressor in the sequence.
When further capacity is either cut out or cut in, the capacity
from the regulating compressor will be modified accordingly
to maintain the pressure within the neutral zone (only where
the compressor has variable capacity).
– When the pressure is higher than the “ref a half neutral
zone”, cut-in of the next compressor (arrow up) is permitted.
– When the pressure is lower than the “reference - a half neutral
zone”, cut-out of a compressor (arrow down) is permitted.
– When the pressure is within the neutral zone, the process
will continue with the currently activated compressors.
Control sensor
Normally, a suction group is controlled based on a signal from
the Po pressure transmitter.
If control on a brine, the S4 sensor must be the control sensor. The
Po pressure transmitter must also be installed, as it is used for frost
protection.
The reference
At set or variable reference can be used for regulation. For
example, the variable reference can be used for a night time
increase or Po optimisation. Enter a set point here so that a
contribution from the Po optimisation or night time increase
is added. This contribution can raise or lower the reference,
as determined by the momentary cooling need.
To limit the reference from values that are too high or too low, set
a max. and min. limit.
Min.
Max.
Po ref.