Time based De-icing started by TEh or TOa
The sensor is not suitable for detecting the end of the deicing phase. Therefore, a
fix deicing time is used. After deicing is finished, an off time is started until the next
deicing phase can be started again. The duration of the off time depends on the
measured temperature at the start of a deicing phase. Deicing time, maximum off
time with assigned temperature and minimum off time with assigned temperature
can be configured.
Humidity influence for TEh or TOa
If an extract air humidity sensor is available, the de-icing limit can be lowered,
because icing is reduced due to dry extract air. Configured de-icing limit refers to a
room / extract humidity value of 80% or higher. This value will be reduced
continuously by a configurable temperature drop until the room / extract humidity
value reaches 20% or lower.
De-icing with increased preheating
In case of possible de-icing, brine coil or ground collector are activated by the
outside air conditions. So they automatically assist the de-icing process.
Preheating with electric heater can be used to assist de-icing. This reduces the
efficiency of the heat recovery and uses electrical energy instead.
Especially when no preheating is available, it is recommended to use the electric
preheater, as otherwise reduced heat exchanger function will result in very low
supply air temperature.
As for normal preheating temperature control, TSuAfPreHcl sensor is used.
Electrical heater is modulated to reach SpPreHDeicng setpoint. The preheater
control runs in this mode until de-icing is finished and switches back to normal
operation running with normal setpoint.
De-icing by increasing the bypass damper position
During deicing, the bypass damper is opened to a configurable value. For open/
close controlled dampers, the value should be set to 100%.
De-icing by reducing fan speed started by differential pressure switch
During deicing the bypass damper, fan speed for supply fan and exhaust fan are
set to configurable values. For faster deicing, it is possible to set the supply fan
speed setpoint even to 0%. In this case electric heaters in the supply air are
blocked.
Application functionalities
Energy Recovery
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