When TGA Consulting
chose to use a Belimo
Fan Optimiser at St
Martins School in Northwood it was
not just to save energy. Large
proportions of the building were to
be used for music practice, so noise
was a key concern.

Using MP bus information, the
optimisers look at the damper
position of each motor and turn the
fan speed down until the damper
position of the most open box is
about 90% open and supplying just
the amount of air that is actually
required. Reducing the amount of
pressure that a damper has to close
off against also reduces noise levels at
each box and therefore in each room.

At St Martins School the system
also incorporates Belimo CR room
controllers which control the heating
valves bringing in heated air through
the VAV units eliminating the need
for additional heating. The CR24-
B3/A3 controllers are linked to PIR
sensors for each room. These shut
down heating and air conditioning
when the room becomes vacant.