Siemens RXB Series Basic Documentation page 77

HVAC application
architecture
Supply chains for a room
Heating
Refrigeration
Outside air
Plant
Operator intervention
Functional units
For internal use only
Siemens
Building Technologies
For a better understanding of the distribution zones for heating and refrigeration,
the following extract is reproduced from document CM110057 "HVAC application
architecture".
Different consumption needs such as heating, refrigeration, and fresh air can be
defined for a room.
The hot water supply chain is available for heating. The medium hot water is
generated in the hot water supply system and distributed via a heating circuit;
demand-based heat is then supplied to the room via a heating surface. If the heat
transfer medium is air, this involves primary and secondary air handling.
The refrigeration requirement is met by the chilled water supply chain. The medium
chilled water is generated in the chilled water supply system and distributed via a
cooling circuit; refrigeration is then supplied to the room according to demand by
means of a cooling surface. When the cooling-energy transfer medium is air, this
involves both primary and secondary air handling.
The outside air is provided by the air supply chain. The medium is treated in the air
handling plant, distributed via the ducting, adapted if necessary by an air
retreatment system to the requirements in the room, and discharged into the room
via air diffusers.
Chilled water
generation
Chilled water
Air
Hot water
Hot water
generation
Essentially, a plant comprises partial plant, aggregates and components, but in
principle, these can equally be expressed in terms of a supply chain with the
following links: energy generator, distribution (primary controller, heating circuit)
and energy consumer (radiator).
For each link in the supply chain, the HMI can be used for commands which affect
the plant (the process) via the relevant functional unit and the automation system.
The functional units correspond to the software mappings of the links in the chain
and the plant elements. They contain all control, monitoring, and limiting functions
required for operation.
KNX bus communications
Appendix
Cooling
circuit
Branch to other rooms
Precontrol
Branch to other
air handling units
Precontrol
Branch to other
terminal units
Air handling
Precontrol
Precontrol
Heating
circuit
Cooling
surface
Terminal
units
Heating
surface
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