The worldwide
standard
for home
and building
control
www.siemens.com/symaro
Energy-efficient control strategy
Air quality based demand-controlled ventilation
In rooms which are not fully
occupied, the outside air flow rate
needs to be reduced to make more
rational use of energy. Demandcontrolled ventilation is the
right energy-efficient solution to
achieve this.
What is a demand-controlled
ventilation system?
Fixed ventilation systems provide constantly sufficient fresh air for full occupancy. The provided volume of heated or
cooled air therefore does not always match
the actual required one. Scheduled ventilation can provide fresh air at the correct
rates at the right time but runs the risk
of under or over ventilation if schedule
changes are not made at the appropriate
times. On the other hand a demand-controlled ventilation system controls the
amount of outside air brought into the
building. It provides just the amount of
outside air the occupants actually need.
Demand-controlled ventilation
with CO2 / VOC* sensors
Demand-controlled ventilation can be
achieved by various means, the most
effective of which is by determining
indoor air quality by the amount of CO2.
Further, there may be additional sources
of odors. New furniture, carpeting,
paint, office equipment, smoke, or other
processes may add contaminants that
overwhelm the designed ventilation or
occupants’ perceptions. VOC sensors
will likely detect these unusual odors.
* VOC: Volatile Organic Compound (mixed gas)
Answers for infrastructure.
The principle of demand-controlled ventilation
Energy consumption
Without demand-controlled ventilation
Without demand-controlled ventilation
BACS efficiency classes – EN 15232
Air
flow
2500 m3/h
2500 m3/h
Maximum occupancy
Time
Low occupancy
With demand-controlled ventilation
Energy savings
Air
flow
2500 m3/h
400 m3/h
Maximum occupancy
A
Advanced BACS and TBM
B
Standard BACS
With demand-controlled ventilation
2500 m3/h
Without demand-controlled ventilation
High energy performance BACS and TBM
Low occupancy
Time
✔
Non-energy-efficient BACS
C
D
With demand-controlled ventilation
High energy performance BACS and TBM
✔
A
Advanced BACS and TBM
B
Standard BACS
C
Non-energy-efficient BACS
D
BACS
TBM Building Automation and Control System
Technical Building Management System
Buildings suitable for demandcontrolled ventilation applications
with most energy saving potential
Demand-controlled ventilation has
the most energy saving potential in
buildings where occupancy fluctuates
during a 24-hour period, is unpredictable, and peaks at a high level.
Examples are:
– Movie theaters, entertainment
and night clubs
– Auditoriums, schools and sport halls
– Restaurants, canteens and cafeterias
– Office buildings, government facilities
– Hotels and convention centers
– Retail stores and shopping malls
Benefits of demand-controlled
ventilation
– Cost savings through energy savings
– Improved comfort and healthy indoor
environment: Demand-controlled ventilation prevents under ventilation that
results in poor indoor air quality
– Cost-efficient solution thanks to retrofit ability in installed base: Demandcontrolled ventilation can be used
on existing, fully operational electric
HVAC systems
Siemens Switzerland Ltd
Infrastructure & Cities Sector
Building Technologies Division
International Headquarters
Gubelstrasse 22
6301 Zug
Switzerland
Tel +41 41 724 24 24
The information in this document contains general descriptions of technical options
available, which do not always have to be present in individual cases. The required
features should therefore be specified in each individual case at the time of closing
the contract.
© Siemens Switzerland Ltd, 2013 • BT_0032_EN
Highlights
■■
nergy savings due to lower
E
power consumption of the
fan and reduced heat losses
of the ventilation system
■■
nhanced room comfort
E
owing to optimum fresh air
supply and lower fan noise
levels
■■
ost-efficient solution thanks
C
to retrofit ability in installed
base