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Induction Ratio
DADANCO's revolutionary STARLINE
nozzle, with it's unique properties, enables entrainment
of surrounding air into the jet at a much greater rate
than conventional nozzles do.
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Conventional |
Dadanco |
Potential "core" zone of the DADANCO
nozzle, with it's enlarged surface area enables more air
to be entrained into the jet in the immediate vicinity
of the outlet of the nozzle.
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| Conventional |
Dadanco |
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Cooling
/ heating duty
As DADANCO nozzles increase induction
(entrainment) ratio of an induction unit, secondary air drawn
through a secondary heat exchanger (coil) is increased for the
same quantity of primary air being discharged through primary
air nozzles.
Cooling/heating duty of a heat exchanger is proportional approximately
to the 1/2 power of the velocity increase (secondary air flow
rate increase) for all other parameters being equal.
Please refer to a table below for expected increase in cooling
capacity of your refurbished induction unit (the values below
depend on cleanliness of heat exchangers, thermodynamic parameters,
etc):
| Entrainment
Ratio |
5% |
10% |
15% |
20% |
25% |
30% |
35% |
40% |
| Capacity |
2% |
4% |
6% |
8% |
10% |
12% |
14% |
16% |
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Total cooling (heating) capacity is a sum
of primary air cooling (heating) capacity and secondary air cooling
(heating) capacity:
Qtot = Qpa + Qsa
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Noise
CFD Modeling shown below shows that length
of the jets are substantially different. In the case of conventional
nozzle (left) jet is much longer than in the case of DADANCO nozzle.
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Conventional |
Dadanco |
It is well known that the sound power level
of the jets is proportional to the 8th power of the
velocity as well as to the length of the potential core zone.
By reducing the length of the core zone, the source of the noise
is being reduced and also the velocity of the jet.
When comparing the noise emanated from old induction units (Carrier,
Trane, Worthington…), for the same primary air flow and pressure,
DADANCO nozzles achieve dramatic noise reduction - of the order
of 5dB(A) to 16 dB(A).
All tests are performed at NATA certified laboratories at The
University of Adelaide, South Australia.
Get a noise test report, prepared by the University of Adelaide
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Primary air pressure
Due to increased entrainment ratio with
DADANCO new technology nozzles, primary air pressure can be reduced
down to 150 Pa (0.6") to 250 Pa (0.79") without any performance
penalty.
For the same cooling/heating capacity required, primary air pressure
can be reduced. This is due to increased secondary airflow through
a secondary heat exchanger that in turn increases its cooling
duty. In order to maintain the same cooling/heating duty, primary
air pressure can be reduced which in turn reduces primary air
flow.
Increase in entrainment ratio and corresponding increase in cooling/heating
duty of a secondary heat exchanger would cater for reduction of
primary air capacity.Collateral benefit of reduced pressure is
reduction of energy consumption of primary a air fan and further
reduction of noise (sound power level) emanated from the units.
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Energy consumption
Energy consumption of a primary air
fan is a major "consumer" of energy in a building. Energy consumption
is directly proportional to the air flow as well as to a pressure
head.
P = (Q x Dp)/h
Reduction
of either Primary Air quantity (Q) or Pressure Head (Dp) that
is now achievable with the novel DADANCO technology, results in
proportional reduction of energy consumption of a subject fan.
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Increased
nett lettable area
Throughout the 50's, 60's and early
70's, considerable proportion of floor mounted (under sill,
wall mounted, etc…) induction units have been installed around
the World.
Those induction units occupy the most valuable area of any property
- perimeter wall area - until now.
DADANCO STARLINE CM induction units have been used widely to replace
Floor Mounted units of various brands. |
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