N
‐
i
‐
HP
Inverter
air
/
water
heat
pump
chillers
with
axial
fans
25
18
CHARACTERISTIC
CURVE
OF
THE
CONTROL
VALVE
FOR
UNIT
IN
PARALLEL
If
the
hydronic
configuration
(CI)
is
installed
on
the
unit
with
the
variant
"shut
off
valve"
(2),
the
head
losses
of
the
ON
/
OFF
motorized
valve
should
be
added
to
those
given
in
the
curves
of
Paragraph
17.
For
example:
for
the
model
N
‐
i
‐
HP
0125
with
nominal
water
flow
1,2
L/s
(4,3
mc/h)
it’s
obtained:
2,0
kPa
(valve
head
loss)
+
32,9
kPa
(hydronic
circuit
head
loss)=34,9
kPa
(total
internal
head
loss).
19
ACCESSORIES
TO
REDUCE
THE
NOISE
LEVEL
19.1
SL
The
silenced
unit
(with
SL
accessory)
is
provided
with
innovating
thermo
‐
acoustic
shells
on
compressors.
These
shells
allow
a
noise
reduction
up
to
10%
at
specific
compressor
rotation
frequencies.
The
special
multi
‐
layer
structure
generates
a
thermal
insulation
which
reduces,
at
very
low
outside
temperatures,
the
heat
losses
of
2%
compared
to
a
standard
insulation.
19.2
SSL
The
super
silenced
unit
(with
SSL
accessory)
is
provided
not
only
with
the
thermo
‐
acoustic
shells
on
compressors
but
also
with
a
special
diffuser
installed
on
the
fan.
The
diffuser
structure
improves
the
air
flow
efficiency
and
allows
a
fan
speed
reduction,
lowering
the
acoustic
pressure
by
up
to
7,2
dB(A)
and
energy
consumption
by
up
to
27%
with
unchanged
airflow.
That
could
lead
to
a
saving
up
of
a
lot
of
money
in
energy
costs
per
fan
per
year.
Alternatively,
you
could
make
use
of
the
greater
efficiency
to
boost
air
performance
by
up
to
9%
with
comparable
energy
consumption.
in KW
1
2
1,5
2,5
-27%
in dB(A)
75
70
80
85
90
-7,2 dB(A
AxiTop
Diffuser
Less
energy
consumption
at
same
air
volume
Reduced
noise
at
same
air
volume
