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Building Technologies Basic documentation: Communication via the KNX bus CE1P3127en
HVAC Products Appendix 30.08.2007
For a better understanding of the distribution zones for heating and cooling, the
following extract is reproduced from document CM110057 "HVAC application
architecture".
Different energy consumption needs such as heat, refrigeration and outside air can
be defined for a room.
The hot water supply chain is available to meet the heating requirement. 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 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.
Branch to other rooms
Cooling
circuit
Precontrol
Heating
circuit
Heating
surface
Cooling
surface
Terminal
units
Air handling
Hot water
generation
Chilled water
generation
Chilled water
Hot water
Room
3127Z40en
Air
Precontrol
Precontrol
Precontrol
Branch to other
air handling units
Branch to other
terminal units
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 operator unit (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 images (mapping) of the links in the
chain and the items of plant. They contain all the control, monitoring and limit
functions required for operation.
HVAC
application architecture
Supply chains for a room
Heat
Refrigeration
Outside air
Plant
Operator intervention
Functional units
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