Special settings
BACnet object
R/RW
Note
ERC Tn
TnHExgCtr
PINTVAL,85
RW
s
Min.diff.room temp./outs.air temp.f.cool
DiffTRTOaMinC
AVAL,164
RW
K
Testing and debugging
BACnet object
R/RW
Note
Heat exchanger device mode
Prio 2: Fire / Smoke
Prio 4: Protection stuck / broken
Prio 5: Protection plant control
HExgDevMod
MVAL,145
RW
1: Off
2: Control mode
3: Max speed
4: Min speed
5: Bypass only
5.9.1.1 ERC De-Icing (rotational)
Active Energy ReCovery units are essentially heat exchangers. They receive warm
and humid air on one side and cold air on the other. Under suitable conditions this
can lead to cumulations of ice on the surface.
Detecting ice on the heat exchanger or in the ductwork
Detecting ice on the heat exchanger or in the duct work is possible by:
●
with the exthaust air temperature sensor TEh. This is not a real indicator, but
an expectation that ice will form.
–
De-icing with TEh sensor starts when TEh is below the limit.
–
The end of the de-icing phase cannot be detected and is estimated via
timer.
●
with a differential pressure switch over the heat exchanger. This possibility
does not detect icethat has built up in the duct work and does not work reliably
on all types of heat exchangers. If the exhaust air temperature sensor and
differential pressure switch are installed, the differential pressure switch is used
to start de-icing.
–
De-icing is active as long as the differential pressure switch is active.
●
with the outside air sensor TOa. This is used when no exhaust air sensor and
no differential pressure switch are available. It is also only an expectation that
ice has formed.
–
De-icing with TOa sensor starts when TOa is below the limit.
–
The end of the de-icing phase cannot be detected and is estimated via
timer.
De-icing the heat exchanger
De-icing is possible by:
●
reducing the speed of the heat recovery, so that the exhaust temperature
increases.
●
reducing the supply fan speed, so that the load of incoming cold air is reduced,
increasing the exhaust air temperature.
●
PI control exhaust temperature to maintain a mimimum exhaust temperature
●
preheating the outside air, increasing the exhaust air temperature
Application functionalities
Energy Recovery
5
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A6V10733786_en_c
