19
Control units VCS
Night Chilling
During night chilling, cold outdoor air is used to cool internal
rooms of the buildings, thus excess heat accumulated in
buildings during the day in summer months is removed. Night
chilling minimizes the use of cooling devices and reduces the
energy demand for temperature control day hours. During
night chilling, the inlet and outlet dampers are fully open and
fans run in the highest output stage. Night chilling start-up
is enabled 12 hours before activation of the selected time
schedule.
Activation
When the following conditions are fulfilled simultaneously:
n T
VEN
> T
MIN
n T
VEN
< T
PRO
- ∆
n T
PRO
> T
ŽÁD
+ T
HYS
Termination
If one of the following conditions is fulfilled:
n Once minimum operating time has elapsed while no time
mode is active (Stop mode)
n T
VEN
> T
PRO
- 1
n T
PRO
<= T
ŽÁD
T
MIN
Minimum outdoor temperature;
T
VEN
Outdoor air temperature;
∆ Outdoor and indoor temperature difference
T
ŽÁD
Required room temperature
T
HYS
Temperature hysteresis
Temperature Start-Up
is feature prevents the building from overheating or over-
cooling. e energy used to maintain a constant temperature
range and system temperature oscillations are lower than
the energy consumption for overheated or overcooled room
control. Air from the room is re-circulated through the air mix-
ing section (mixing damper fully open). e fan speed is set
to the highest output stage. During temperature start-up, it
is possible to select whether the inlet and outlet dampers or
dampers along with the outlet fan will be blocked. is can
be performed using the HMI controller, refer to the chapter
Additional Operating Mode and Function Setting Options.
Cooling
Activation
When the following conditions are fulfilled simultaneously:
n T
PRO
> T
S,CH
n Once the t
BL
time interval has elapsed
Termination
If the following condition is fulfilled:
n T
PRO
< T
S,CH
- T
HYS
Heating
Activation
When the following conditions are fulfilled simultaneously:
n T
PRO
< T
S,O
n Once the t
BL
time interval has elapsed
Additional Operating Modes
Termination
If the following condition is fulfilled:
n T
PRO
> T
S,O
+ T
HYS
T
PRO
Required room temperature
T
S,CH
Starting temperature for cooling
T
S,O
Starting temperature for heating
T
HYS
Temperature hysteresis at the stop
t
BL
Heating blocking time
t
BEH
Time remaining to start the time schedule
Optimized Start
is feature is used to ensure the comfortable temperature
to be reached before the time schedule has been activated.
us possible initial temperature non-conformities aer the
time schedule activation are removed. is feature includes the
setting for the room ventilation to have the room temperature
controlled as soon as possible. is is based on air recirculation
within the room along with cooling or heating adjustment. e
mixing damper is fully open.
It is possible to select whether the inlet and outlet dampers
will only be blocked or whether the outlet fan will be blocked
as well.
Cooling
Activation
When the following conditions are fulfilled simultaneously:
n T
PRO
> T
S,CH
+ T
HYS
n t
∆TP
< t
KOM
Termination
If the following condition is fulfilled:
n T
PRO
< T
S,CH
Heating
Activation
When the following conditions are fulfilled simultaneously:
n T
PRO
< T
S,O
- T
HYS
n t
∆TP
< t
KOM
Termination
If the following condition is fulfilled:
n T
PRO
> T
S,O
T
PRO
Required room temperature
T
S,CH
Required temperature set-point for cooling
T
S,O
Required temperature set-point for heating
T
HYS
Temperature hysteresis
t
KOM
Pre-set interval before time program start-up
t
∆TP
Time remaining to the time program start-up
Night Turning Feature
When the supply air temperature sensor is not present, the
outlet air temperature is evaluated. As the temperature is
measured in the outlet, the fans are started at specified time
intervals and air from the room is drawn into the outlet duct.
e night turning feature is used along with the night chilling
or temperature start-up modes. Night turning can be specified
by the turning start time, time remaining to next turning and
turning duration time.