Assortment / System Description

Central app
lications
Automation station for HVAC supply and demand signals and manual control for lighting and blinds
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24.1.3 HVAC supply chain chilled water over BACnet
The following list includes all data points that can be read and written from a
BACnet primary plant. The items ensure coordination between primary plant
and the room. In addition, appropriate Desigo primary application for the given
room function is mentioned.
Data point name Description Desigo primary application
CReq The central function prepares
one chilled water demand
acquisition and evaluation to
the connected rooms for the
primary plant. The enumerate
result can include:
1:Off
2:Cooling demand
3:Free cooling
4:Cooling demand & free
cooling
Values 3 and 4 set refrigeration
generation to free cooling on
primary chilled water
generation.
PXC {CGrp65}
SpCReq Setpoint for cooling request PXC {CGrp65}
FreeCAvl Free cooling available
0:No
1:Yes
PXC {CGen10}
FreeCTChw Free cooling temperature
chilled water
PXC {CGen10}
ChwTOa BACnet reference for primary
plant: Outside temperature of
the chilled water supply chain
Data point outside temperature
of chilled water supply chain
Setpoint for cooling request influenced by:
● Base setpoint for cooling
● Valve position(s) of cooling valve in the group
● Number of active condensation monitor in the group
● Dew points
The cooling request setpoint is influenced by the evaluation of valve positions.
ChwVlvPosEvl Supply chain chilled water valve position evaluation
▶Average of the largest valve position
ChwSpCorrTFlHi Supply chain chilled water setpoint correction for higher flow temperature
ChwSpCorrTFlLo Supply chain chilled water setpoint correction for lower flow temperature
Figure: Setpoint cooling request
Setpoint for cooling
request.