VAV variable air volume applications
The drawing shows a typical application for CMR duct-averaging velocity
Veloprobes, V-sensors and P-sensors.
The supply air duct can either be fitted with one central Veloprobe or
individual Veloprobes on each of its branches. In many cases, the positions
of the Veloprobes are very much dictated by the design of the building. The
CMR Veloprobe can be fitted in almost any position in order to provide the
necessary results.
In a single supply and single extract duct application the V-sensor measures
the building's actual supply and return volumes. As both V-sensors are
calibrated to provide a linear air volume signal, synchronisation of supply
and extract air is made simple. The Veloprobes are easily adjusted by the
commissioning engineer during final commissioning.
For multiple duct applications, the total supply air volume is derived by
adding measurements from individual ducts. The same applies to the return
air where the following formulae can be applied:
S = E ± an offset for positive or negative building pressure
S1 + S2 + S0 = E1 + E2 +/-
offset
S = E1 + E2 ± offset
Veloprobes are made to specification up to 4 m length. The V-sensor is
designed for nominal flows of 3, 9, 13, 20 and 28 m/s. Other ranges are
available on request.
All V-sensors and P-sensors can be interlinked with a bms system or the MPC
100 computer network in order to achieve easy remote scaling and
controlling.
In order to specify the devices quote:
(a) duct size and shape
(b) air volume in cubic metres per second
and metres per second
(c) type of bms or control needed, ie 0 - 10 V,
4 - 20 mA or RS 485 signal
(d) mounting position
(e) distance from mounting position of
V-sensor to Veloprobes
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