Firmware V1.4
20.05.2021
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5.8 Gas cooler bypass GCBP
The gas cooler bypass is a valve and bypass line to bypass the gas cooler. This allows the heat generated by
the refrigeration pack system to be retained in the building.
The WRG 3010 E supports both digital changeover valves and continuously regulating valves. The valve
must
be correctly parametrised (digital/continuous), otherwise fault signals will occur due to other feedback signals
from the valve.
The GCBP operation is only enabled as soon as
the GCBP switch-on threshold has been
reached. It is disabled again if the value falls below the GCBP switch-off threshold. There is one exception; if
there are parallel compressors with a heat exchanger for suction gas superheating in the system and this
function is enabled in LDSWin, the gas cooler bypass valve is also enabled. However, this only applies to the
continuously regulating valve; for details, see chapter
.
Gas cooler bypass with digital switching valve
If the gas cooler bypass operation is enabled and no defrosting of the LWP is active and the high pressure, the
tg1 and the water return temperature are OK (see setpoints), the GCBP valve is opened. The high pressure,
the tg1 temperature and the water return temperature are constantly monitored. If any of the 3 shutdown criteria
is met or the request goes away, this will result in immediate closing of the GCBP valve and the lockout time will
start. If a sensor break at the HP sensor or tg1 sensor is transmitted by the
GCBP valve to close, as these are important control and monitoring variables. The GCBP valve cannot be
opened again until the lockout time has expired.
The valve reports both end positions back to the controller,
where "open" stands for bypassing the gas cooler
and "closed" for introducing the hot gas into the gas cooler.
The feedback of the valve must always match its actuation. If this is not the case, an alarm is sent to the system
centre. Due to the run times of the installed valve actuators, there is a waiting time of 260 seconds when
switching over, during which no alarms are output.
Gas cooler bypass with continuously regulating valve
The continuously regulating valve has the same requests as the switching valve. The difference is that it can
also bypass partial quantities of the hot gas and thus leave more heat energy in the building.
It receives the setpoint "GCBP Soll tg1" for regulation and the actual value tg1 comes from the
The valve must have a control range of 2-10 volts and the response must correspond to this. Due to too high a
deviation between the actuation of the valve and its response, the fault message is generated and also output
to the system centre with a delay of 260 seconds.
If the suction gas superheating of the parallel compressors is intended and parametrised and the air
conditioning operation starts, the controller of the GCBP valve receives the setpoint "GCBP Solltg1 Klima" and
regulates it in the same way. If there are separate water circuits for LT and air conditioning and if the PV suction
gas superheat is parametrised, the setpoint "GCBP Soll tg1" always has priority for heat recovery.
If an air heat pump is configured and has been in operation for a configurable period of time (see chapter
), the LWP is defrosted with hot gas. The GCBP valve is closed during defrosting to ensure
rapid progress.
This applies both to the digital switching valve and to the continuously regulating switching
valve.
GCBP is an option and does not have to be present in all installations.
The prerequisite for this operating mode is that this function has been selected in the visualisation, for
details, see figure
Visualisation in LDSWin - GCBP / LWP / air conditioning operation setpoints
Gas cooler bypass operation is only possible in combination with a
connected to the
CAN bus. The high pressure and the tg1, as well as their sensor faults are transmitted cyclically from
this.