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If you do not wish to use winter offsetting alone, and want to keep summer offsetting active,
the winter offset setpoint must be entered with a value below the values that the air
temperature is supposed to reach in winter.
If you do not wish to use summer offsetting alone, and want to keep winter offsetting active,
the summer offset setpoint must be entered with a value above the values that the air
temperature is supposed to reach in summer.
6.7.5 Enthalpy-based free cooling/free heating
The software can control the temperature and humidity of the air in the room.
When probes are fitted to measure the temperature and humidity of both ambient and external air, and the
dampers are installed, free cooling and free heating can be managed by enthalpy instead of by temperature.
When enthalpy-based management is enabled, the controller calculates the enthalpy setpoint based on the
temperature and humidity control setpoints: it calculates the values of the ambient and external air enthalpy
using the corresponding temperature and humidity probes.
Once these values are known, the following cases may be observed.
1) External enthalpy (EN est) is greater than ambient enthalpy (EN amb), which, in turn, is higher than
the enthalpy setpoint (Set EN). Alternatively, external enthalpy (EN est) is smaller than ambient
enthalpy (EN amb) which, in turn, is smaller than the enthalpy setpoint (Set EN). In these cases
enthalpy-based free cooling is not efficient, so the dampers cause switching to other functions.
2) Internal enthalpy (EN amb) is smaller than the enthalpy setpoint (Set EN), which, in turn, is smaller
than external enthalpy (EN est). Alternatively, internal enthalpy (EN amb) is greater than the enthalpy
setpoint (Set EN) which, in turn, is greater than external enthalpy (EN est). Enthalpy-based free cooling
is efficient in these cases: damper opening will be controlled according to the gap between the ambient
enthalpy and the enthalpy setpoint. Free cooling remains active as long as the ambient enthalpy value
equals the enthalpy setpoint.
3) Internal enthalpy (EN amb) is greater than external enthalpy, which, in turn, is higher than the enthalpy
setpoint. Alternatively, internal enthalpy is smaller than external enthalpy which, in turn, is smaller than
the enthalpy setpoint. Enthalpy-based free cooling is efficient in these cases when the difference
EN (KJ)
EN est.
EN amb. Set EN
EN (KJ)
EN est.
EN amb.
Set EN
EN (KJ)
EN est.
EN amb.
Set EN
EN (KJ)
EN est.
EN amb.
Set EN