Carel k.Air, User Manual, Page: 73 / 192

73
Functions k.air +030220981 rel. 1.2 - 01.12.2020
The actions are summarised below:
Heating mode C ooling mode
R eturn temp. control Increase in the heating device output as the fi rst stage and reduction in
humidifi er output as the second stage. Humidifi er output reduction
S upply temp. control Humidifi er output reduction The heating devices are controlled to keep
the supply temperature constant, if suffi
ciently sized, humidifi er output
is not reduced.
Humidifi er output reduction
Tab. 9.aa
R if D escription D ev Min Max UoM D ir Modbus BAC net
HUMI D I F I CA TI ON
F004
Humidifi cation PID parameters - Proportional gain 8.0 0.0 999.9 - R/W HR1549 AV3050
Humidifi cation PID parameters - Integral time 120 0 999 - R/W HR1550 PIV3051
Humidifi cation PID parameters - Derivative time 0 0 999 - R/W HR1551 PIV3052
F008
Humidifi er: Max humidity threshold 80.0 1.0 100.0 %rh R/W HR1552 AV3053
Humidifi er: Max humidity proportional part 8.0 0.0 999.0 - R/W HR1553 AV3054
Humidifi er: Max humidity integral time 50 0 999 s R/W HR1554 PIV3055
F012
Low supply temperature threshold 16.0 0.0 25.0 °C R HR1354 AV2862
Humidifi er: Min temperature proportional part (Only adiabatic hum) 8.0 0.0 999.0 - R/W HR1555 AV3056
Humidifi er: Min temperature integral time (Only adiabatic hum) 100 0 999 s R/W HR1556 PIV3057
F020
Parameters for device confi guration - Timings for washing operations -
Delay time between two consecutive washes (mins)
30 0 999 - R/W HR1557 IV3058
Parameters for device confi guration - Timings for washing operations -
No production time for inactivity wash (hours)
24 0 999 - R/W HR1558 IV3059
Parameters for device confi guration - Timings for washing operations -
Washing phase time (fi ll + drain) (mins)
2 0 99 - R/W HR1559 IV3060
F024 Manual drain request: FALSE=no request; TRUE=request to drain - 0 1 - R/W CS252 BV252
F028
Number of working hours left before check the humidifi er cylinder - 0 65535 - R IR514 PIV3828
Parameters for device confi guration - Hours counter reset request - 0 1 - R/W CS253 BV253
Tab. 9.ab
Note:
if CAREL humiSonic or Humifog humidifi ers are used, the humidifi er must be confi gured according to the commissio-
ning procedure, as described in the specifi c manuals or technical leafl ets.
9.15 D ehumidifi cation
Dehumidifi cation is controlled by a main cooling or mixed coil, when appropriately enabled (Ac04).
The main function for calculating the dehumidifi cation request uses PI control, and the control probe, in common with the
humidifi cation function, is selected between: return, room or supply. Control can be based either on the absolute humidity or
relative humidity value (Ac32). The dehumidifi cation load will be transferred to the cooling coil using two modes, selectable
by parameter (Ac34):
• Cooling request
• Dew point
In cooling request mode, the request from the humidity controller is applied directly to the cooling coil signal. If there is already
a cooling request, as these are compatible with each other, the higher request will be applied.
In dew point mode, the humidity control request is used to calculate the set point for a second PI algorithm (cascade control),
relating to the dew point. The increased request due to humidity control will lower the dew point set point. Subsequently, the
dew point control function will gradually increase the cooling coil capacity until reaching the (dynamic) dew point measured
using the saturation probe, which is required in this mode. The supply temperature is however limited to the minimum supply
set point value.
30220980_166_R01
St
0%
0%
T_dew_pt
T_dew_pt - ∆
100%
100%
Room humidity
Request (%)
Request (%)
Supply_temp_set
diff. Key
Room umidity Room humidity
Request Humidity request
St Humidity set point
Diff Diff erential (100/kp)
Supply_temp_set
Supply temperature set point
T_dew_pt Dew point
Fig. 9.ad