Fans | Air Handling Units | Air Distribution Products | Fire Safety | Air Curtains and Heating Products | Tunnel Fans
Air Handling Units
NB Units (Normabloc)
Disclose the secret of fresh air!
Systemair has been taking care of
Indoor Air Quality (IAQ) as an essential
resource since 1974. Today Systemair is
one of the leading ventilation companies
worldwide. A success story, which started
in Skinnskatteberg, Sweden with the
invention of the inline duct fan. This
invention revolutionised the ventilation
world. Since then the company has
continuously advanced and now offers a
comprehensive range of products for all
ventilation requirements. The expert at
Systemair have the required knowledge
when considering the ventilation of
shopping centres, domestic ventilation of a family home to the complex
ventilation of tunnels and metro stations. More than 2500 employees
and in excess of 60 subsidiaries in 40 countries globally we are available
to our customers.
With this catalogue which features air handling units fans and
accessories we give you as our customer a general overview of what
Systemair can offer within this range, particulary with the NB AHUs.
For futher information you can just visit our online catalogue
on www.systemair.es.
© Systemair 2011. Systemair reserves the right to make technical changes. For updated
documentation, please refer to www.systemair.es or www.systemair.com
2 | AHU NB
Index
Systemair ......................................................
4
Quick selection tips ..................................... 26
Product range ..............................................
6
NB Air Handling
Unit Selection (Normabloc) ....................... 27
Air handling units - Overview ...................
8
General advice ............................................. 10
Tools .............................................................. 11
Examples of applications ........................... 12
Introduction .................................................. 15
Selection in a sample project .................... 28
Sections in detail ......................................... 34
NB Selection Program ................................ 45
Applicable regulations and Quality
.................................... 46
Modular air handling units NB .................. 16
Description of the series ............................ 18
UNE 1886: 1999 / 2007 ............................ 47
Descripton of the Air Handling Unit ......... 19
Technical Assistance Service ..................... 47
AHU NB | 3
Systemair
The straight way
Technical data
production idea and led to the circular
duct fan. Today “the straight way”
represents our ambition to simplify the
life of our customers. Stocked products
are delivered in Europe within 24 hours
from local warehouses and within 72
hours from distribution centres. High
product quality, correct technical data
and fast deliveries are always in focus.
Our development centre in
Skinnskatteberg is one of the most
!
measurements, acoustic measurements,
$ measurements on air terminal devices,
etc. All measurements are performed in
compliance with applicable standards as
set out in AMCA and ISO.
Systemair
*+
9001 and ISO 14001. Our quality system
allows us to continuously improve our
products and our customer service.
undertaken to minimise our
environmental impact. We always take
the environment into consideration when
we choose sub-suppliers, materials,
production methods, etc. An important
factor is that we continuously work to
reduce our energy consumption and
reduce waste. Through increased recovery
and heightened awareness we have been
able to reduce our waste by 90%. Quality
and environment management systems
are under continuous development. These
are audited twice a year by the
&<=>*?<= Quality International).
Systemair was established in Sweden in
1974 and is today the parent company in
an international group with 60
subsidiaries and approximately 2,500
largest production plant is located in
Skinnskatteberg with some 400
!"#$###2.
Production
We are proud of our production units.
The aim has been to have both effective
production of bulk products and, at the
$ !% &
approach to producing small volumes.
This has steered our choice of machinery
and how we plan our production, with
focus on the working environment. Our
premises are light and pleasant and we
invest in tools that facilitate work and
provide our employees with a safe and
'
Quality and environment
Dal, Eidsvoll – Norway
In Eidsvoll, Norway we manufacture
air handling units for the Norwegian
market. The Norwegian warehouse
for fans is also located here.
Bouctouche - Canada
In Bouctouche, Canada we primarily
produce duct fans and heat
exchangers used in residential
ventilation for the North American
market.
Detailed product information can be found
on our website, www.systemair.com
Kansas City – USA
In Kansas City we produce roof fans,
roof extractor fans, wall fans and
recirculating air units.
Production in Skinnskatteberg is virtually fully automated with modern machinery
featuring advanced computer support. Also located here is the company's most
advanced test installation for measuring technical data.
4 | AHU NB
Hässleholm - Sweden
Skinnskatteberg - Sweden
Main plant
Klockargården
VEAB
The main plant in Skinnskatteberg
houses one of the company's two
central warehouses and the largest
production installation as well as
V accessories are produced here as stock
items.
Systemair's small air handling
units are made at Klockargården
in Skinnskatteberg. Frico’s central
warehouse of approximately 8,000
m2 is also located here.
=J< LR hot air fans.
Ukmerge – Lithuania
Production of air handling units for
homes.
Bratislava – Slovakia
The factory in Bratislava
manufactures air terminal
Maribor – Slovenia
The factory in Maribor, Slovenia
specialises in high temperature fans
! Kuala Lumpur – Malaysia
Production and marketing of products
for tunnel and garage ventilation.
Madrid – Spain
Hasselager - Denmark
Windischbuch - Germany
The factory in Madrid, Spain makes
air handling units for the southern
European market.
The factory in Hasselager, Denmark
manufactures large air handling units.
All production here is order based.
In Windischbuch, Germany a
broad assortment of fans are
manufactured, of which the majority
are stock items. One of Systemair's
central warehouses is located here.
AHU NB | 5
Product range
Systemair has an extensive range of ventilation products, the majority of which are fans and air handling units.
Other products include a wide range of air terminal devices for various applications.
$ $ $ $ $
industrial buildings, tunnels, parking garages, training facilities, sports centres.
The most common usage is comfort ventilation, but safety ventilation in various forms is also an important market.
Smoke gas ventilation and tunnel ventilation are two examples.
FANS
Circular duct fans
Rectangular duct fans
Systemair is one of the world’s largest
suppliers of fans for use in various types
of property.
Duct fans with a circular connection.
Duct fans with a rectangular connection.
Radial fans
Box fans
Single-inlet radial fans.
For extract air systems that transport
normal or high-temperature media.
Axial fans
Roof fans
Axial fans for duct connection or wall
mounting.
Roof fans with a circular or square connection.
Explosion-proof fans
Jet fans
Thermo fans
Explosion-proof fans for duct, roof and
axial installations.
The jet fan range includes products for
garages and road and rail tunnels.
Systemair supplies high temperature fans
that can withstand conditions of up to
600°C for 120 minutes.
Our range includes everything from
duct fans with a round connection –
the company’s original product - to
rectangular duct fans, roof fans, axial
fans, explosion-proof fans, and smoke
gas fans.
These fans can be supplied in sizes
suitable for everything from ducts with
a diameter of just 100 mm to large road
tunnel fans. All our fans have been
developed to comply with stringent
requirements and are characterised by
user-friendliness, a high level of quality
and a long service life.
6 | AHU NB
FIRE SAFETY VENTILATION
Smoke gas fans
Fire dampers
Systemair produces fans, dampers and
control equipment for protection against
' normal operation and in the event of
% '
areas.
High-capacity fans for evacuation of smoke
gases.
Dampers that reduce the spread of smoke
RESIDENTIAL VENTILATION
Residential units
Cooker hoods
Y units with heat recovery and builtin control systems. Designed to be
mounted over the cooker, on walls or
horizontally in attics.
For homes with living areas of 60-320 m2.
Good at capturing odours even at low
! AIR TERMINAL DEVICES
Supply, extract & transfer
air terminal devices
Nozzle air devices
Systemair’s range also includes a wide
selection of air terminal devices for all
possible environments and positions.
Development and manufacture take
place at a modern factory in Slovakia.
Optimum air distribution for rooms.
For mounting in ceilings or walls.
Supply & extract air ventilators
Duct products
For mounting in ceilings and walls.
Dampers, plenum boxes, and duct accessories.
AHU NB | 7
Air handling units - Overview
larger industrial applications. Common to all items in the range is that systems and components have been
developed to satisfy stringent demands for low energy consumption. Heat exchangers, motors and fan units
% $& & $ and future demands for low energy consumption.
All products are also manufactured to comply with environmental requirements. To ensure easy installation,
many of these units feature control systems enabled for plug-and-play, i.e. simple start-up.
NB
1000
0.14-24 m3/s
2000
5000
10000
20000
40000
80000
70
Modular air handling units intended for
large premises. Available in 15 sizes.
Large number of combinations. Suitable
for technically demanding environments.
m3/h
62
55
49
42
35
29
23
18
15
11
8
5
3
Technical data ...............................16
TA
0.07-1.25 m3/s
2
0.2
0.5
200
1
2
500
3
1000
5
1500
10
2000
m3/s
20 25
15
4000
6000
4500
Supply air handling units intended
for small to medium-sized premises.
Available in 7 sizes and supplied
complete with control system, fan,
m3/h
3000
2000
1500
1100
650
450
0.05
F
0.1
500
0.13-0.97 m3/s
0.3
0.2
0.4
1000
0.5
1500
m3/s
2
1
2000
3000
m3/h
False ceiling units for small and mediumsized premises. Available in 3 sizes and in
3 versions.
035
030
016
0.1
8 | AHU NB
0.2
0.3
0.4
0.5
1
m3/s
1.4
500
1000
1500
2000
3000
m3/h
2000
1100
0.08
0.1
0.3
0.2
200
500
0.5
0.4
1000
1500
m3/s
1
2000
4000
6000
m3/h
15
Topvex TR (rotating heat exchanger)
Topvex TX (cross-flow heat exchanger)
06
04
03
0.1
0.3
0.2
200
500
0.5
0.4
1000
1500
4000
6000
m3/h
11
Topvex SR (rotating heat exchanger)
Topvex SX (cross-flow heat exchanger)
06
04
03
0.1
1500
0.3
0.2
2000
0.4
4000
0.5
1
6000
10 000
15 000
m3/h
25
20
15
10
1500
0.5
2000
3000
1
5000
2
10 000
Topvex SR/SX
0.1-1.9 m3/s
TIME
0.4-4.0 m3/s
Compact air handling units with heat
recovery, intended for medium-sized
premises. Available in 6 sizes and
supplied complete with control system.
Also available with heating coil and
cooling coil.
30
0.4
0.09-1.9 m3/s
m3/s
2
40
0.3
Topvex TR/TX
Compact air handling units with side
Y! exchangers, intended for medium-sized
premises. Supplied complete with control
system. Equipped with EC motors and can
be supplied with an electric or hot water
heating coil.
09
07
0.05
Compact air handling units with a low
overall height and heat recovery, intended
for small and medium-sized premises.
Available in 2 sizes and supplied complete
with control system. Also available with an
electric or hot water heating coil.
m3/s
2
1
2000
0.1-0.56 m3/s
Compact air handling units with top
Y!
heat exchangers, intended for mediumsized premises. Supplied complete with
control system. Equipped with EC motors
and can be supplied with an electric or
hot water heating coil.
12
09
0.05
Maxi
3
20 000 30 000
m3/s
5
4
50 000
90 000
m3/h
240
190
DV
0.4-24 m3/s
Modular air handling units intended for
large premises. Available in 14 sizes.
Large number of combinations and
options.
150
120
100
80
60
50
40
30
25
20
15
10
0.4
0.7
1
2
3
5
10
15
20
m3/s
25
AHU NB | 9
General advice
A good indoor climate is vital
It goes without saying that everyone prefers fresh air. We are also aware of the fact that we must be carefull
'[ ! & ventilation systems with energy and saving the earth’s resources and protecting the environment.
\ & ]^$ Y climate. Systemair has products that have been specially adapted to protect the environment with
well-thought-out material consumption and production methods. These products are also designed
to be economic in terms of energy consumption. The best of Systemair’s ventilation products are
labelled “Green ventilation”.
Heat recovery
Pressure
In areas with a relatively low average
annual temperature, ventilation systems
employ effective heat recovery that
returns energy from extract air to
the supply air. A good rotating heat
exchanger can recover up to 90% of the
energy present.
The design of the duct system and
the unit has an impact on required
system pressure. There are often tens,
sometimes hundreds, of Pascals to be
saved here.
Today, there is a new generation of fan
motors that contribute to a dramatic
reduction in energy consumption, as much
as 50% in some cases. The new EC motors
are better suited to speed control functions,
which is where considerable energy
savings can be made. A bonus of this is also
quieter operation.
Night cooling
In warmer parts of the world, energy
savings may be possible by drawing
cool night-time supply air into premises,
thus cooling the building structure.
CE-marked products, but is that enough?
At Systemair we are going one step
further and working hard to ensure that
our products maintain a high standard
and are approved by various bodies.
For units, this may mean Eurovent
the country in question. To achieve this,
you need resources and expertise. Within
$ $ things, one of Europe’s most modern
development centres, which is AMCA How can you choose the right solution
and product when there are so many
alternatives? Nowadays, most major
*+Y One of Europe’s most modern development centres
A room that is so quiet that the only thing
you’ll hear is your heartbeat.
The development centre in Skinnskatteberg,
&J[J$ _`{##$### with measurement and testing equipment,
making it one of the most modern facilities
of its kind in Europe.
The quiet room is one of the test stations
or a “reverberation chamber”, producing a
background sound of less than 10 dBA. When
measuring supply air terminals, a green laser
is used to show how the air is expelled from
wall-mounted or ceiling-mounted devices.
There is also a climate chamber that
cools the air to -20°C, which means we
can use it all year round to develop our
recovery units. As well as the test centre
in Skinnskatteberg, there are also test
facilities in Germany and Denmark.
10 | AHU NB
Tools
We have developed this overview to make it easier for you to get an idea
More detailed analysis or planning usually requires additional information,
which is where the following tools come in.
Product catalogue
More detailed technical information,
planning, is available in separate
For those who prefer to work online, it is
possible to read catalogue online.
In addition to complete product information,
there is also a selection software that suit
actual needs. There is computer software
that you can download and install locally
from www.systemair.es.
Systemair aims to have local expertise close to the customer.
~ Y Y &
$ AHU NB | 11
Examples of applications
Different types of plant – same basic requirements
All buildings are there to create a “climate shell”, regardless of whether
the aim is cleaner air or a cooler or warmer climate than the external
surroundings.
Here are a few examples where Systemair’s air handling units have been
used and the conditions and requirements that applied.
Topvex
TA
F
Maxi TR
TX
SR
SX TIME
SIMPLE PROJECT IMPLEMENTATION
Simple project implementation for expansion of existing premises or new buildings.
NB
TIME DV
FLEXIBLE SOLUTIONS
Flexible solutions with heat recovery and intelligent control functions that are easily
$ NB
TIME DV
LARGE VOLUMES OF AIR
When choosing central plants, you will usually need units capable of handling large
volumes of air and sometimes the option of communicating with an integrated
control system.
Topvex
TA
F
Maxi TR
TX
COMPACT SOLUTIONS
Changed needs when upgrading or renovating a building usually mean new
requirements for air handling. Extreme space-saving solutions and connections for
units that can also be split for easier transport and handling at the construction site
are able to satisfy all new demands.
Topvex
TA Maxi TR
TX
SR
SX TIME DV
COMMUNICATION
Integrated control systems. The nature and complexity of requirements for
controlling units and functions vary depending on the size of a project. Our
factory-integrated solutions with various levels of equipment can handle
everything from the simplest requirements to the toughest demands.
12 | AHU NB
+ & ventilation during the day as well as
heat recovery and reheating of supply
air depending on external conditions.
= & J $ develop an excess of heat produced by
people, lighting, solar radiation, computer
equipment, etc. In many cases there
is a need to cool the air and prevent
uncomfortably high temperatures. In larger
buildings that accumulate heat energy
easily, you should consider employing
* $ & * $ also considerable need to reduce the noise
generated by the ventilation system.
Schools/day nurseries
A school environment means a lot of
people present at certain times of the
day, i.e. generally there are relatively
large variations. This means that it should
be possible to use demand control for
the ventilation system. Normally, heat
recovery is warranted. There will be short
periods during the year when cooling may
be required. However if there is effective
sunscreening, then air conditioning is rarely
required. High demand for low noise levels.
At day nurseries, activities, such as cooking,
that create odours are common, so there
is often a need for supply air and extract
air to be kept separate. There must be
heat recovery in the form of a plate heat
exchanger, for example.
Shops
As a rule, the number of people in a shop
changes constantly throughout the day,
making a control-on-demand ventilation
system the sensible option. Recirculating
air in combination with carbon dioxide
control (CO2) and heat recovery can be
one optimised solution for these types of
premises.
When there are few people present, CO2
levels will be low and an increased amount
of return air can be mixed into the system.
As the number of people present increases,
the amount of return air is reduced and
replaced with fresh outdoor air.
If heating is required at night-time, the
premises are warmed up using 100%
recirculating air.
AHU NB | 13
Industry
Industrial premises will often have high
! ' generates high levels of air pollution. If the
pollutants are also aggressive, there may
be requirements that affect the choice of
material used. Systemair offers products
for different environmental classes that can
cope with tough environments. Filtration of
& demands.
Hotels
The requirements for ventilation in hotels
are characterised by demands relating to
$ noise levels. The choice of air handling unit
will probably be affected by these demands.
What is important here is good functions for
speed control and quiet operation.
In addition to quiet air handling units with
demand control, Systemair can also supply
Healthcare premises
Healthcare premises can encompass
numerous activities, everything from
operating theatres to wards. The activity
determines the requirements. Operating
theatres will have stringent demands for
cleanliness and ventilation. Wards require
low noise levels. If several areas are served
by the same system, the unit must have
demand control and possibly even subsystems.
Systemair’s range of air handling units
can satisfy all requirements relating to
healthcare premises, whether these have
to do with air cleanliness, noise levels or
demand control.
14 | AHU NB
Introduction
The air handling unit (AHU) is one of the most essential and
critical units to be considered when designing an air
conditioning system.
The characteristics of the cooling and heating units can be
defined on the basis of the estimated cooling and/or heating
power.
This air conditioner is designated by us and other industry
manufacturers as an air handling unit. The latter designation is
popular within the company and has been used routinely in all
previous editions of the NB catalogue. We will also use it in
this catalogue to refer to our well-known, popular and efficient
NB air handling unit.
= & & apparatus defined by three dimensions and with a series of
specific components.
The importance of the air handling unit in the system is readily
understood, as it modifies the air conditions for final treatment
of air conditioned environments and is placed downstream of
all other installed equipment.
Both the construction layout and the physical location of the
installed air handling unit means that it is extremely difficult to
adjust at a later date to conditions much different from those
established during the original selection process. For this
reason, the equipment must be carefully and precisely
selected.
L=J  range of NB air handling units, which includes equipment for
air flows between 500 and 87,000 m3/h, with static pressures
of up to 200 Pascals.
Special care has been taken in the preparation of the
catalogue to ensure a user-friendly document. Only a little
effort is needed to obtain a rather precise overview of the air
handling unit required, with clear, concise information on the
most important characteristics. Based on our experience, these
are key data for the start of any project.
Additional information can be used to identify each of the
characteristics to be taken into account in the precise, complete
The front surface, and therefore the width and height of the
equipment, is defined on the basis of the air flow rate.
The type of fan and the motor can be selected on the basis of
the designed static pressure.
Example NB Unit.
AHU NB | 15
Modular air handling units NB
^< && !% & ' design. As we do not have standard unit combinations, units can be
adapted to suit customer requirements.
Unit housing
Keywords
The unit housing is made from aluzinc
185 sheet steel and sandwiched panels.
The outside of the unit housing has
a stove-enamelled surface in our
characteristic new grey colour. Panels
are available in two different versions:
€ Available in 15 different sizes
€ L ! "##Y
90.000 m3/h
€ For use with low,
intermediate or high air
pressure systems.
€ Heating and cooling units
€ % € Heat recovery sections
€ Two different types of air
25 mm – which is the standard version.
The panels are attached directly to the
framework.
"# when more effective heat insulation is
required. These panels are attached to
{#%{# aluminium sections.
J ‚ polyurethane insulation foam, which
has excellent heat and sound-insulating
properties. Rockwool panels are optional
as well.
Range and software
Detailed information on NB units you
can get with the product selection
software. Both are easy to use and
are available from your nearest
WORKING RANGE
2, 3, 5, 8
Ps [Pa]
qv [m3/h]
1000
600
2000
3000
4000
5000
3,0
550
500
6000
7000
8000
350
NB2
NB3
NB5
NB8
NB11
2,5
2,5
2,5
400
10000
3,0
3,0
450
9000
2,5
2,5
2,0
300
2,0
2,0
250
2,0
2,0
200
150
1,5
100
50
1,5
1,5
1,5
1,5
0
0.2
x,x
16 | AHU NB
0.4
0.6
0.8
= SFP value (Specific Fan Power)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
qv [m3/s]
11, 15, 18, 23
Ps [Pa]
qv [m3/h]
8000
600
10000
12000
14000
16000
18000
20000
22000
24000
26000
28000
3,0
550
NB11
NB15
NB18
NB23
NB29
2,5
500
2,5
450
2,5
2,5
2,5
400
2,0
350
2,0
300
2,0
250
2,0
2,0
200
1,5
150
1,5
100
1,5
50
1,5
1,5
0
2.0
2.5
x,x
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
qv [m3/s]
= SFP value (Specific Fan Power)
29, 35, 42, 49
Ps [Pa]
qv [m3/h]
20000
600
25000
30000
35000
40000
45000
50000
55000
60000
2,5
550
2,5
500
2,5
450
2,0
400
2,0
2,0
300
1,5
200
2,5
2,5
2,0
350
250
NB29
NB35
NB42
NB49
NB55
2,0
1,5
150
100
1,5
1,5
1,5
50
0
5
6
x,x
7
8
9
10
11
12
13
14
15
16
17
= SFP value (Specific Fan Power)
18
qv [m3/s]
55, 62, 70
Ps [Pa]
qv [m3/h]
50000
600
55000
60000
65000
70000
75000
85000
800 00
NB55
NB62
NB70
3,0
550
2,5
500
2,5
450
400
2,5
350
2,0
300
2,0
250
2,0
200
150
1,5
100
50
1,5
0
13
x,x
14
15
= SFP value (Specific Fan Power)
16
17
1,5
18
19
20
21
22
23
24
qv [m3/s]
AHU NB | 17
Description of the series
L=J  ^&J L _ „" ^<Y† ^<Y{#_ $! & "##‡{$###3/h can be handled, with rates
as high as 87,000 m3/h when the unit is used exclusively for hot-air heating.
INLET SECTION
COOLING/HEATING SECTION
FAN SECTION
DISCHARGE OUTLET
FILTERS
HEATING/COOLING UNIT
DRIVE
FAN
The use of three types of double-inlet centrifugal fans allows
the equipment to be selected for use in low-, medium- or
high-pressure air systems, depending on the project
characteristics.
Several options are also available for the heat exchangers.
The heating units installed can use different heating fluids
such as:
Hot water; Superheated water; Steam; Electricity, etc.
The most commonly used cooling media are:
Chilled water; Glycol water; Direct expansion of coolants, etc.
An extensive range of air filters can handle a variety of
filtering needs, from simple impurity filtering to absolute
filtering, within the limits established by the manufacturer for
the filtering media.
The use of two types of standardised humidifiers allows the
media to be freely selected. Furthermore, additional sections
can be used to mount any type of humidifier available on the
market.
A set of 19 well-differentiated sections complete the assembly
to allow the intake of outside air, mix it with returned air, filter
it, heat it, cool it, humidify it, recover heat, provide access to
the equipment interior, etc.
18 | AHU NB
Once completed, the air handling unit features a smooth,
exterior line with a solid, sturdy, aesthetically pleasing look
that fits with the surroundings.
Descripton of the Air Handling Unit
Casing
The metal enclosure that covers all the components contained
in the Normabloc air handling units is sturdy and has no
protruding items to disturb the overall look of the unit.
chemical foam to the metal sheet significantly increases the
mechanical strength.
This type of insulation has become extremely popular and is
the unquestionable market leader in Spain and other European
Union countries.
Air handling units with a smaller cross-section (NB-2 to NB-18)
have a frame composed of an aluminium section that outlines
the equipment edges perfectly, resulting in a solid, robust and
attractive overall look.
Polyurethane foam was introduced many years ago for the
insulation of air handling units. Anyway we use rock wool or
fiber glass upon request.
These aluminium extruded sections are joined by injectionmoulded fibreglass-reinforced plastic angle cleats.
The construction approach used in our Normabloc air handling
unit has become a market leader since its introduction in the
late 1970s.
In air handling units with a larger cross-section (NB-23 to
NB-70), the assembly includes a frame composed of a
specially shaped section of extra-thick steel with high bending
strength, due to the pleats in frame. These pleats create the
housing of the closing panels, leaving an outer bevelled edge.
In these larger sizes, the sections are joined together by angle
cleats manufactured of die-cast aluminium. The assembly is
anchored by slot screws, obtaining a solid, sturdy structure.
The NB panels are manufactured in two nominal thicknesses:
25 mm, which is the standardised panel, and
50 mm, which meets specific needs requiring greater heat
insulation.
The 25-mm thick NB panels are mounted on the two
structures mentioned above.
The 50-mm thick NB panels are mounted on a frame
composed of an aluminium profile of 70 x 70 mm, which
outlines the equipment edges precisely. Due to its width, the
50 mm NB panel is flush with the extruded aluminium frame,
providing an overall solid, robust, attractive appearance.
The frame sections are joined by angle cleats manufactured of
die-cast aluminium.
The frame enclosure is based on the use of NB sandwich
panels comprising two pieces of galvanised sheet one inside
the other.
The inner rack is manufactured of galvanised steel sheet,
whereas the exterior rack of the same material has
a baked-on pre-enamel finish in the characteristic aluzinc
L=J & of the two racks is filled with an injected polyurethane foam
insulation to ensure excellent thermal and sound insulation
that prevents heat transfer, noise transmission and potential
condensation.
The injection-moulding process is done with the panel
introduced in a press with hot plates, which promotes
polymerisation and avoids panel deformation due to the
expansive strength of the polymer.
This method results in a mechanical stiffness well above that
of other panels filled with other type of insulation (even when
the panels have thicker sheets), as the adhesion of the
Corner detail.
The above solution is applicable to all NB models with a
50-mm panel (NB-2 to NB-70).
Regardless of the type of structure, all NB panels on the
access side can be easily dismounted, thereby facilitating
access to the internal parts of the air handling unit by the
maintenance staff.
AHU NB | 19
By special order, the NB panels can be constructed with a
different shape for specific needs.
All internal components of the air handling units are secured to
the structure and the NB panels by butts of galvanised sheet.
These butts have various shapes, based on the specific
component.
The finished equipment can have a bedplate composed of
channel sections or feet. Based on the project needs, it can
also be set on shock absorbers when vibration must be
avoided.
The enclosure described contains all the air handling unit
sections, which can include some or all of the ones described
below:
Mixing section
This has similar features as the above and two openings, each
of which contain a control damper.
These dampers can be supplied with an extruded aluminium
section construction. There are two models of aluminium
section, one with an airfoil blade.
The operating mechanisms for all dampers are installed in the
channel frame. This allows air to circulate freely and facilitates
installation in closed ducts. The mechanisms and fasteners are
made of corrosion-resistant materials.
Inlet section
This section is composed of a standardised section with an air
inlet to the air handling unit.
This opening can:
Use a volume control damper, that can be equipped for
manual operation or for subsequent automation.
Be protected by an air shutter.
The combination of the previous two.
Be equipped with a simple inlet consisting of a straight
flange for easier duct connection;
In addition, a cover to prevent water from entering when the
equipment is placed outdoors can be provided.
Hinges detail.
The operating mechanism of the dampers may be manual or
equipped for motor-driven operation. In the latter case, upon
request and depending on the damper size, these controls can
be supplied interconnected so they can be operated by a
single servo drive.
Window detail.
20 | AHU NB
Free cooling section
Filter section
This section requires a return fan and a supply fan. These fans
must have three dampers in between, with the dampers used
to regulate the volumes of exhaust, return and outside air.
The following sections of filters are included in the NB Air
Handling Unit standardised range:
Therefore, in order to meet their purpose the dampers must be
motor-driven.
When the enthalpy of the outside air is less than the enthalpy
of the recirculated air, i.e., during spring and autumn, the
mixture of outside air and recirculated air is controlled to
achieve free cooling.
Extended surface filters, in which the filtering mat is
mounted in zigzag fashion. As a result, the filtering area is
larger, the air flow rate is low, and the service interval for
replacement or cleaning is longer.
The filtering efficiency is low; and therefore the unit can be
used in systems for human comfort where the atmosphere
has a low level of contamination.
Consequently, the relative opening of the dampers is
determined by an enthalpy (or dry temperature) comparator,
which sends the respective signal to the damper motors.
In order to ensure the minimum ventilation air required in
cooling or heating seasons, the outside air inlet damper can be
split into two sections (one motor-driven and another manual
that remains fixed). The cross-section of the damper will be
proportional to the minimum ventilation air flow.
This effect can also be achieved more economically by
adjusting the stroke of the motor operating the outside air
damper so it does not close completely.
Plate
Bag filters, which can be flexible or stiff and have a
medium or high filtering efficiency, depending on the class.
The bag filters have an individual frame and airtight seals.
They are particularly recommended for installations
requiring extra-pure air.
The bag filters are generally preceded by a prefilter section
of lower efficiency (e.g., extended surface filters). This
approach extends the service life of the bag filters, which
are more costly and must be replaced, as they cannot be
regenerated.
Absolute filters, with an efficiency of almost 100% as
indicated by the name. They are equipped with an individual
frame and airtight gaskets.
AHU NB | 21
Similar to the other filters, which must contain a prefilter
section upstream, the prefilters should be high efficacy
filters to ensure a longer service life. They are costly and
cannot be re-used.
Hepa
Cooling/heating section
The cooling and heating units are composed of the enclosure
described above, which contains the tube-and-fin heat transfer
unit, mounted on a special joint cover.
For air cooling processes, units composed of copper pipes and
aluminium fins (Cu/Al) are normally used.
At the bottom, the cooling section has a stainless steel pan for
collecting condensation and a small hose to drain the
condensation toward the outside. The pan is slightly tilted for
easier drainage, in order to prevent the proliferation of harmful
bacteria such as Legionella pneumophila.
Direct expansion units are also used for cooling. These units
can be equipped with one or two manifolds.
For heating processes, the same type of copper/aluminium
units used for cooling is normally used.
If the air might contain corrosive chemicals, copper tube and
fin (Cu/Cu) units should be used to improve the corrosion
resistance of the equipment. This type of unit is more
expensive than the copper/aluminium unit.
In facilities where the heating fluid is at high temperature and
pressure (e.g., steam, superheated water or special thermal
fluids), units composed of steel tubes and fins (Fe/Fe), which
have a much higher strength, should be used. This type of unit
is more expensive than the copper/aluminium unit.
Electrical heating units can also be installed upon request,
depending on the customer’s needs.
Germicide section
We can analyse the use of a germicide section to improve the
quality of the air supply only upon request.
An adequately designed germicide section should ensure that
all bacteria flowing through the system are subjected to the
bactericidal radiation necessary for its disposal.
The emitters should be installed in areas prone to bacterial
growth, such as cooling units, drip pans and other moist areas,
in other words, in any parts that have adequate conditions for
bacteria development.
The use of this equipment will improve the air quality of the
treated environments, as well as the heat exchanger efficiency
of the units, minimising the need for cleaning and maintenance
of the units and the drip pan.
If the specified exposure times are used, these emitters can
attack microbes on surfaces or suspended in the air that are
growing, circulating or being distributed in the air handling
units, and which are largely responsible for allergies and other
air-borne diseases.
Access section
This section, which has a hinged access door and is equipped
with an enclosure and handle, is sandwiched in the air
handling unit configuration to allow access to the lower parts
that require surveillance or regular maintenance.
22 | AHU NB
It may also be used to hold any type of auxiliary component,
such as a perforated jet humidifier for direct humidification
with steam, or other types of components.
Recovery section
Rotating regenerative air-to-air recovery unit, specially
designed to transfer sensitive (temperature) and latent
(humidity) heat from the exhaust air to the supply air.
The supply air stops in one of the halves of the heat recovery
unit, while the exhaust air circulates in counterflow through
the other half.
When the impeller turns, the small air flowing channels
comprising the impeller are alternately in contact with clean air
and with return air, transmitting heat and moisture from one
circuit to the other.
The outside air flows through the other unit, which heats the
air while it cools the circulating water, with the latter heated
again in the return circuit, creating a continuous sensitive-heat
recovery cycle in the air.
In order to ensure proper system operation in winter, facilities
with an extremely low outside air temperature must use glycol
water.
Benefits achieved from the installation of any of these heat
recovery systems:
Reduced heating plant power, minimising equipment sizes
in terms of boilers, fuel tank, circulating pumps, heat pipes
and heating units.
Reduced cooling plant size (compressors and condensers or
cooling towers), circulating pumps, pipe grid and cooling
units. Savings in operating power consumption for heat and
cold generation.
Any of the recovery systems mentioned in this section can be
installed upon request only, as they are not included in the NB
standardised range.
Static recovery unit with air-to-air crossflow designed to
transfer sensitive (temperature) heat; in this type of heat
recovery unit, the supply air is completely separate from the
exhaust air, in order to prevent any type of contamination
from one air stream to the other.
Humidifier section
Heat transfer takes place through the plate separating the two
streams.
Panel humidifier, composed of a standardised enclosure,
including a stainless steel drip pan at the bottom.
Two adjacent plates form a small duct for exhaust or supply air.
The enclosure houses the humidifier panel, which has
crosswise corrugated channels to ensure minimum air
resistance as well as a large contact surface between
the air and water, thereby releasing moisture into the
circulating air.
The plate-to-plate distance varies, depending on the size and
efficiency requirements.
Recovery unit composed of a dual unit in a closed air-to-air
circuit. Designed to transfer sensitive (temperature) heat, using
units manufactured with copper pipes and aluminium fins (Cu/Al).
The method is simple and economic, as the return air flows
through one of the units, heating the water that circulates
inside and is then exhausted.
Two different types of air humidifiers can be installed in our air
handling units. In both cases, the units are adiabatic
humidifiers.
The top of the panel contains a water manifold, to which the
water is pumped through the pipework from the drip pan by
means of a small submersible electrical pump.
Water is distributed vertically by gravity, coating the entire
inner panel surface with an extremely fine film. As the air
flows by the panel horizontally through the spaces provided,
turbulent flow conditions are established, thereby resulting in
efficient transfer of heat and moisture.
The humidifier panel is manufactured of two different types of
material:
Fibreglass. Mixed with structural additives for stiffening.
Fibreglass is the material we recommend for the
construction of equipment with materials accepted by
current regulations, as it helps prevent the appearance of
Legionella.
Cellulose. With chemical additives, allowing it to absorb
water without affecting its stiffness.
AHU NB | 23
Fiber glass
Usage is not advisable, since current regulations recommend
that materials promoting the development of bacteria and
fungi be avoided (e.g., leather, wood, fibre cement, concrete
or cellulose derivatives).
Legionella is an aerobic (oxygen-requiring) bacterium that
causes two critical forms of disease in humans:
One form is known as “Legionnaire’s disease” and affects
the lungs, causing high fever. It is serious and can be fatal in
many cases.
The other, milder form is known as “Pontiac fever”.
These bacteria are found naturally in aquatic media and enter
the human population through the public water mains.
The conditions required for proliferation are:
Presence of a substrate acting as a food source (e.g., grime,
algae, microorganisms, iron oxides, calcium, magnesium or
silicon salts)
Appropriate temperature.
The bacterium is carried through the air in water droplets.
Droplets between 1 and 5 microns (aerosols) provide the
necessary conditions for human infection.
Infection takes place through the airways.
Ways to prevent infection:
Water treatment with disinfectants to ensure quality.
Periodic testing of the physical, chemical and biological
parameters of the water.
Periodic cleaning and disinfection of the installation to
ensure safe operation.
Air scrubber, composed of an enclosure with a large drip pan
at the bottom.
The tray contains enough water to create steady state
conditions in the scrubber system and is equipped
with hoses to connect the circulating pump (supplied
24 | AHU NB
when requested by the client) and water supply, drain
and overflow fittings.
The inside contains a distribution branch with water spray
nozzles. Two distribution branches are used to increase the
efficiency of the humidifier.
A drop separator with blades designed to hold drops in the air
is installed on the air outlet side, ensuring that no drops are
carried to other sections.
In order to prevent leaks of water, the entire section is
watertight and has an access door equipped with a sighthole
for visual inspection.
This type of air scrubber can be manufactured entirely of
reinforced polyester (both the enclosure and the drip pan) to
prevent corrosion.
The equipment that includes the air scrubber comes with a
bedplate composed of steel channel sections which are used
to support the entire air handling unit.
The air scrubbers are installed exclusively by special order, as
they are not included in the NB standardised range.
Fan section
Silencer section
This section is composed of a double inlet cone centrifugal fan
with an anchor bedplate, drive and electric motor or plug-fan.
The baffles of the silencer section are constructed of natural
galvanized steel sheet, with a peak at the air inlet end to
decrease the head loss. The baffles are also filled with a
sound-insulating material composed of fibreglass with an
appropriate density. This material is also heat-resistant and its
outer face is protected against air erosion.
If centrifugal fan motor assembly is mounted on Silentbloc
bushings and the discharge outlet is joined to the opening in
the enclosure by means of a flexible synthetic seal.
This allows the unit to run without external transmission
of the small vibrations normally caused by fan motor
assemblies.
The standardised NB air handling units can contain three
different types of fans:
Two of them have forward-facing impeller blades and are used
in facilities designed to run with low-pressure air flow. These
fans are identified with the AT and ADH codes.
The third, which has backward curved blades and is designated
RDH, is used for facilities with medium- or high-pressure air
flow.
The three types of fans are carefully manufactured, which
ensures perfect operation, as perfect static and dynamic
balance.
Y =Y& The air discharge outlet of the fan section has a straight tab
for easier connection to the duct system.
In some cases where the noise level of the facility should be
minimised, the inside of the panel is covered with a sheet of
perforated plate equipped with pleats, that contains a
fibreglass insulating layer with neoprene film on the exposed
side to prevent particle creep.
There are two options:
PA. The sound insulation is protected against erosion due to
air flow by a flame-retardant protective layer.
This is the most common approach in ventilation and air
conditioning systems.
PAM. Equal to PA, but with an additional polyester-film
coating (Melinex).
Used for applications with acidic, alkaline or oily gases, as it
can be steam-cleaned.
Recommended for hospitals, since bacterial colony
formation is not possible.
These two models can be constructed with four lengths of baffle.
Special sections
In addition to the standardised sections, other special sections
that meet specific requirements can be analysed by special
order and included in the air handling unit assembly designed
expressly for the conditions of your project.
This assembly is secured to the standardised panel by tubular
rivets, obtaining a fan section that can absorb most of the
noise generated by the fan motor, in this case radiated sound
pressure.
Example belt driven fans.
AHU NB | 25
Quick selection tips
IMPORTANT INFORMATION
1. These fast selection criteria are included to help the user choose the equipment for the design specifications.
Nevertheless, this selection method is not precise enough to indicate the equipment that best fits your requirements.
If more precise information is necessary, please use our computer-aided selection program (available on CD-ROM) or
talk to our Sales Department.
2. The dimensions and weights used in the following pages correspond to equipment constructed with 25-mm thick NB
Panel.
3. Remember: the following formula must be used to determine the air velocity (m/s):
Air velocity =
Flow rate m3/s
Afo m2
= m/s
4. The data used to determine the number of rows of the units are based on the following values:
inlet air
26,4ºC, 48,4% RH.
outlet air
13,0ºC, 92,0% RH.
inlet air
18,0ºC
outlet air
30,0ºC.
Cooling:
Heating:
5. The fan features refer to operation in facilities with free inlet and channelled supply outlet, and do not take into
account any air flow fittings.
6. The absolute fan power consumption does not include losses attributable to the drive.
A diagram is included so the size of the right air handling unit
can be quickly selected for each case (see next page).
Based on the air flow rate and air velocity through the heat
exchanger units, the diagram indicates the most adequate
unit, as well as the relationship with the nearest units in terms
of size.
The most common practice is to define the air velocity through
a cooling unit at 2.7 m/s, and 3.5 m/s for heating only. These
are approximate values only. For further information, refer to
the section on heating and cooling units provided below.
There are two pages with the most relevant data on this
model for the selection of each air handling unit model in this
standardised range.
Example:
An air handling unit is needed for an air flow of 19,200 m3/h:
On the selection diagram, start with the scale in m3/h and
vertically locate the point where this flowrate has the velocity
of 2.7 m/s, in this case the one that corresponds is the NB-23
Air Handling Unit.
26 | AHU NB
MODELO
NB-2
70000
80000
87000
60000
50000
40000
30000
20000
6000
7000
8 000
9000
10000
5000
4000
3000
2000
1500
500
Normabloc Air Handling Unit Selection (NB)
afo.
m2
0.18
2.0 2.5 3.0 3.5 m/s
NB-3
0.30
2.0 2.5 3.0 3.5 m/s
NB-5
0.51
2.0 2.5 3.0 3.5 m/s
NB-8
0.82
2.0 2.5 3.0 3.5 m/s
NB-11
1.15
2.0 2.5 3.0 3.5 m/s
NB-15
1.44
2.0 2.5 3.0 3.5 m/s
NB-18
1.80
2.0 2.5 3.0 3.5 m/s
NB-23
2.22
2.0 2.5 3.0 3.5 m/s
NB-29
2.89
2.0 2.5 3.0 3.5 m/s
NB-35
3.55
2.0 2.5 3.0 3.5 m/s
NB-42
4.22
2.0 2.5 3.0 3.5 m/s
NB-49
4.90
2.0 2.5 3.0 3.5 m/s
NB-55
5.57
2.0 2.5 3.0 3.5 m/s
NB-62
6.24
2.0 2.5 3.0 3.5 m/s
NB-70
6.91
2.0 2.5 3.0 3.5 m/s
SELECTION DIAGRAM J ! $ 3/h.
AHU NB | 27
Selection in a sample project
Pressure drops
in mm w.g.
Air velocity, m/s
Section
2.50
2.75
3.00
3.25
3.50
E
2
2
3
3
4
Air mixture.
M
2
2
3
3
4
Extended surface filters.
FC
2
2
3
3
4
Cooling unit based on chilled water.
F
9
11
13
15
18
Hot-water heating unit.
FB
19
23
27
Low-pressure fan section.
FA
56
58
60
4
Horizontal air handling unit, composed of the following sections:
S-234 (700 mm)
2
2
3
3
Technical data:
S-334 (1050 mm)
2
3
3
4
5
Air flow rate: 19,200 m3/h;
S-434 (1400 mm)
3
3
4
4
5
Available static pressure: 45 mm w.g.;
S-534 (1750 mm)
3
4
4
5
6
Cooling power: 99,100 -kcal/h;
HP
11
13
15
Chilled water temperature: 7ºC;
HL
8
9
10
Temp. difference of chilled water: 5ºC;
BF 2R
5
6
BF 3R
7
8
BF 4R
9
10
BF 5R
10
12
BF 6R
12
14
BC 1R
3
3
4
4
BC 2R
4
5
6
7
7
Temp. difference of heated water: 15ºC;
BC 3R
6
7
8
9
10
Conditions of inlet air: 18.0ºC BS;
BC 4R
7
8
9
11
12
Conditions of inlet air: 26.4ºC BS, 48% RH;
Conditions of outlet air: 13ºC BS, 92% RH;
Temperature rise of motor: approx. 1ºC;
Heating power: 69,120 kcal/h;
Hot water temperature: 85ºC;
NOTUSED
5
Conditions of outlet air: 30.0ºC BS.
Code
E
M
FC
F
FB
FA
BF
BC
A
HP
HL
V
S
NB Air Handling Unit Selection (Normabloc)
Using the quick selection table, the appropriate model for a flow rate of air of
19,200 m3/h and an air velocity of 2.7 m/s is the NB-23 with a front surface
(afo) of 2.22 m2.
Step 1:
To determine the air velocity through the unit:
First, divide the flow rate of air expressed in 600 m3/h by 3600 seconds to
obtain the flow rate of air in m3/s:
Section
Air inlet
Air mixture
Free Cooling
Extended surface filters
Bag filters
Absolute filters
Cooling unit
Heating unit
Access
Panel humidifier
Air scrubber humidifier
Fan
Silencer
19.200 / 3.600 = 5,33 m3/s
Divide this flow rate, in m3/s, by the afo for the NB-23 air handling unit, in m 2,
to obtain the air velocity in m/s:
Air velocity through heating/cooling unit= 5,33/2,22 = 2,4 m/s
Determination of the number of rows in the unit
CALEFACCIÓN
HEATING
Heating, water 85/70º
2.5
Step 2:
3.0
3.5
Air velocity
m/s.
ENFRIAMIENTO
COOLING
Cooling, water 7/12º
2.0
2.5
KCAL/HR.
600.000
To determine the number of rows and depth of each cooling and heating unit,
with an air velocity of 2.4 m/s:
Air velocity
m/s.
FR/HR.
130.000
500.000
Cooling, water at 7-12ºC, 99100 -kcal/h = 4R
400.000
Heating, water 85/70ºC, 69120 kcal/h = 1R
3.0
4R
3R
2R
300.000
200.000
120.000
6R
110.000
5R
100.000
4R
90.000
80.000
1R
100.000
3R
2R
28 | AHU NB
70.000
Step 3:
Step 5:
Determine the static pressure of the air handling unit by
adding the various pressure drops for the unit for an air velocity
of 2.4 m/s:
Determine the dimensions and weight of the air handling unit:
M
F
BC (1 R)
BF (4 R)
=? ‹
10 HP motor
Air mixing section (M)
Extended surface filter section (F)
Heating unit (BC) 1R
Cooling unit (BF) 4R
2 mm w.g.
9 mm w.g.
3 mm w.g.
9 mm w.g.
______________
Total sum for the air handling unit
Available static pressure
23 mm w.g.
45 mm w.g.
______________
Total static pressure
68 mm w.g.
Section
Dimensions
Weights
920 mm
175 mm
175 mm
525 mm
„ŒŒ"
202 kg
39 kg
78 kg
180 kg
Œ†'
52 kg
___________________________________
TOTAL
3.240 mm
893 kg
The air handling unit will have the following dimensions and weight:
Step 4:
Length
3.240 mm
Determine the operating conditions of the fan, in this case for
low speed, ADH 560 model, on the respective curves:
Width
2.190 mm
Height
1.490 mm
Weight
893 kg
The pressures indicated on the curves are “total pressures”.
Therefore, the dynamic pressure (Pd) for 19,200 m3/h of air flow
must be added to the static pressure obtained earlier:
Total pressure (Pd + Pe) = 6,5 mm + 68 rnm = 74,5 mm w.g. Total pressure
increase (Pt)74,5 mm w.g. = 74,5 x 9,80665 = 730,6 = approx. 731 Pa
The air outlet mouth air are 721 x 721 mm.
The air inlets are 800 x 1700 x 672 x 1900 mm.
The following values are obtained from the intersection of the air
flowrate and total pressure:
750 r.p.m.Input power:
87 dBEfficiency:
10,2 m/s
$'+ PP
:+((/ ',$0(7(5
327(1=$ &86&,1(77,
%($5,1* 32:(5
',$0(752 *,5$17(
.
U
.J P
.
*,5,P
530
5(1'7279/$ ,03(//(5 727$/ ()) /5
.:
/5
.
.
.
:
:
:
:
8
5
2
0
7
4
2
Motor output = 6,0 kw. x 1,2 = 7,2 kw (10=HP)
3D
1P
.
The input power can then be used to calculate the motor output:
727$/ 35(6685(
Revolutions:
6,0 kwSound power:
66 %Air outlet velocity:
Kg
56
V (w/o motor)
53
F
22
BF 2R
46
FB
40
BF 3R
51
FA
55
BF 4R
55
A (Each 175-mm clear)
11
BF 5R
59
S-234 (700 mm)
32
BF 6R
63
S-334 (1050 mm)
37
BC 1R
29
S-434 (1400 mm)
42
BC 2R
33
S-534 (1750 mm)
47
BC 3R
38
BC 4R
42
Bedplate - weight per metre
16
FC
190
HL
33
M
100
HP
26
E
Sections
/: $ LQ G% $
Kg
35(66,21( 727$/(
Sections
SECTION WEIGHTS
3RUWDWD
; MOTOR WEIGHTS
Power (HP)
Kg
Power (HP)
Kg
0,33
5
1,5
16
0,5
5
2
16
0,75
9
3
30
1
9
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3D
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AHU NB | 29
UNIT VERSIONS WITH CENTRIFUGAL FANS
In order to facilitate the work of designing an air handling unit based on the numerous options available, we have provided
& % preferred unit with the right functions. Choose the unit version that best matches your preferences and then add or remove
functions as required.
= outdoor air
= supply air
= extract air
= exhaust air
SIZE
ROTATING HEAT EXCHANGER
Panel 25
2
3
5
Width
760
760
1130
Height1)
1170 1520 1560 2260 2260 2960 2960 2980 3680 4380 4380 4380 4380 4380 4380
Width
810
Panel 50
Height
C1V
Panel
25
Panel
50
C2V
Panel
25
Panel
50
C3V
Panel
25
Panel
50
C4V
Panel
25
Panel
50
C5V
Panel
25
Panel
50
C6V
Panel
25
Panel
50
1)
Length
Weight2)
810
8
11
15
18
23
29
42
49
55
62
70
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
1270 1620 1660 2360 2360 3060 3060 3060 3760 4460 4460 4460 4460 4460 4460
2860 2860 2880 2880 3230 3230 3580 3940 4290 4640 4640 4990 5340 5340 5340
481
576
813
1051 1289 1575 1852 2629 3105 3535 4891 5470 6030 6590 7150
Length
2940 2940 2940 2940 3290 3290 3640 3990 4340 4690 4690 5040 5390 5390 5390
Weight2)
553
Length
2860 3035 3230 3405 3755 3755 4105 4465 4815 5165 5165 5515 5865 5865 5865
Weight2)
549
Length
2940 3115 3290 3465 3815 3815 4165 4515 4865 5215 5215 5565 5915 5915 5915
Weight2)
608
Length
3035 3035 3230 3405 3930 3930 4280 4815 5165 5690 6215 6565 6915 6915 6915
615
658
704
849
917
959
1194 1453 1775 2074 2920 3450 3932 5321 5934 6529 7124 7719
1248 1518 1861 2164 2992 3535 4029 5452 6080 6689 7298 7907
Weight2)
519
622
Length
3115
3115 3290 3465 3990 3990 4340 4865 5215 5740 6265 6615 6965 6965 6965
Weight2)
597
664
Length
3210 3385 3755 3930 4455 4455 4805 5340 5690 6215 6740 7090 7440 7440 7440
Weight2)
593
Length
3290 3465 3815 3990 4515 4515 4865 5390 5740 6265 6790 7140 7490 7490 7490
Weight2)
657
Length
3035 3035 3230 3405 3930 3930 4280 4815 5165 5690 6215 6565 6915 6915 6915
711
760
878
1098 1347 1644 1932 2693 3181 3622 5012 5605 6178 6751 7324
917
990
1135 1392 1701 2000 2839 3353 3818 5282 5908 6512
7117 7722
1186 1455 1776 2087 2908 3435 3912 5413 6053 6672 7291 7910
1290 1569 1917 2240 3154 3726 4247 5747 6409 7051 7694 8337
1036 1348 1639 2010 2337 3231 3818 4351 5888 6566 7224 7882 8540
Weight2)
510
611
Length
3115
3115 3290 3465 3990 3990 4340 4865 5215 5740 6265 6615 6965 6965 6965
Weight2)
586
652
Length
3210 3385 3755 3930 4455 4455 4805 5340 5690 6215 6740 7090 7440 7440 7440
Weight2)
582
Length
3290 3465 3815 3990 4515 4515 4865 5390 5740 6265 6790 7140 7490 7490 7490
Weight2)
644
697
746
862
900
972
1114 1366 1670 1963 2787 3291 3747 5184 5798 6392 6985 7579
1164 1428 1743 2048 2855 3372 3839 5313 5941 6549 7156 7763
1266 1540 1882 2198 3095 3657 4168 5640 6290 6921 7551 8182
1017 1323 1609 1973 2294 3172 3747 4271 5779 6445 7090 7736 8381
Dimensions in mm. Weights in kg.
1)
Does not include the height of the metal frame. 2) Does not include the weight of the metal frame.
30 | AHU NB
35
SIZE
PLATE HEAT EXCHANGER
Panel 25
2
3
5
Width
760
760
1130
Height1)
1170 1520 1560 2260 2260 2960 2960 2980 3680 4380 4380 4380 4380 4380 4380
Width
810
Panel 50
Height
Q1V
Panel
25
Panel
50
Q2V
Panel
25
Panel
50
Q3V
Panel
25
Panel
50
Q4V
Panel
25
Panel
50
Q5V
Panel
25
Panel
50
Q6V
Panel
25
Panel
50
1)
810
8
11
15
18
23
29
35
42
49
55
62
70
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
1270 1620 1660 2360 2360 3060 3060 3060 3760 4460 4460 4460 4460 4460 4460
Length
2860 3035 3055 3230 3930 4280 4630 5165 5690 6040 6565 7090 7440 7440 7440
Weight2)
553
Length
3080 3255 3255 3430 4130 4480 4830 5355 5880 6230 6755 7280 7630 7630 7630
Weight2)
636
Length
3035 3385 3580 3755 4455 4805 5155 5690 6215 6565 7090 7615 7965 7965 7965
662
707
757
935
976
1209 1482 1811 2130 3023 3571 4065 5625 6291 6935 7579 8223
1263 1549 1891 2222 3097 3658 4165 5764 6446 7105 7764 8423
Weight2)
631
Length
3115 3465 3640 3815 4515 4865 5215 5740 6265 6615 7140 7665 8015 8015 8015
Weight2)
699
Length
3035 3210 3405 3755 4630 4980 5330 6040 6565 7090 8140 8665 9015 9015 9015
810
1103 1435 1746 2140 2489 3441 4065 4633 6270 6992 7692 8393 9093
Weight2)
597
Length
3115 3290 3465 3815 4690 5040 5390 6090 6615 7140 8190 8715 9065 9065 9065
Weight2)
687
Length
3210 3560 3930 4280 5155 5505 5855 6565 7090 7615 8665 9190 9540 9540 9540
Weight2)
682
Length
3290 3640 3990 4340 5215 5565 5915 6615 7140 7665 8715 9240 9590 9590 9590
Weight2)
755
715
1055 1373 1671 2041 2385 3358 3968 4522 6119 6824 7508 8193 8877
764
817
874
1010 1305 1601 1956 2300 3265 3856 4390 6075 6794 7489 8185 8880
1054 1364 1673 2042 2400 3345 3951 4499 6225 6961 7673 8385 9096
1139 1483 1805 2205 2576 3627 4285 4884 6609 7370 8109 8848 9587
1191 1550 1885 2311 2688 3716 4390 5004 6771 7551 8308 9064 9820
Length
3035 3210 3405 3755 4630 4980 5330 6040 6565 7090 8140 8665 9015 9015 9015
Weight2)
586
Length
3115 3290 3465 3815 4690 5040 5390 6090 6615 7140 8190 8715 9065 9065 9065
Weight2)
674
Length
3210 3560 3930 4280 5155 5505 5855 6565 7090 7615 8665 9190 9540 9540 9540
Weight2)
669
Length
3290 3640 3990 4340 5215 5565 5915 6615 7140 7665 8715 9240 9590 9590 9590
Weight2)
741
702
750
802
858
991
1281 1571 1920 2258 3205 3785 4309 5962 6668 7351 8033 8716
1035 1338 1642 2004 2355 3283 3878 4415 6110 6832 7531 8229 8928
1118 1455 1771 2164 2528 3559 4206 4793 6486 7234 7959 8684 9409
1169 1521 1850 2269 2638 3647 4309 4911 6646 7412 8154 8896 9639
Dimensions in mm. Weights in kg.
1)
Does not include the height of the metal frame. 2) Does not include the weight of the metal frame.
AHU NB | 31
LIQUID-COUPLED HEAT EXCHANGERS
2
3
5
Width
760
760
1130
Height1)
1170 1520 1560 2260 2260 2960 2960 2980 3680 4380 4380 4380 4380 4380 4380
Width
810
Panel 25
Panel 50
Height
R1V
Panel
25
Panel
50
R2V
Panel
25
Panel
50
1)
S2V
Panel
25
Panel
50
15
18
23
29
35
42
49
55
62
70
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
1270 1620 1660 2360 2360 3060 3060 3060 3760 4460 4460 4460 4460 4460 4460
Weight2)
483
Length
2240 2415 2590 2765 3115
Weight2)
529
Length
Weight2)
Length
Weight2)
579
619
794
829
1045 1297 1488 1849 2706 3184 3666 4439 4975 5539 6103 6670
3115 3290 3640 3815 3990 3990 4165 4340 4340 4340
1091 1355 1653 1930 2775 3260 3756 4548 5098 5675 6252 6829
2685 2860 3055 3230 3580 3580 3755 4115 4290 4465 4465 4640 4815 4815 4815
551
662
898
1187 1461 1688 2071 2997 3529 4062 4868 5439 6038 6637 7236
2765 2940 3115 3290 3640 3640 3815 4165 4340 4515 4515 4690 4865 4865 4865
610
707
939
1241 1526 1865 2161 3071 3616 4162 4988 5572 6187 6802 7417
SIZE
2
3
5
Width
760
760
1130
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
Height1)
585
760
780
1130
Width
810
810
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
Height1)
635
810
830
Length
1810 1985 2180 2355 2705 2705 2880 3240 3415 3590 3590 3765 3940 3940 3940
Panel 50
Panel
50
11
2160 2335 2530 2705 3055 3055 3230 3590 3765 3940 3940 4115 4290 4290 4290
Panel 25
Panel
25
810
8
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
Length
SUPPLY AIR UNITS
S1V
SIZE
Weight
2)
207
243
338
8
11
15
18
23
29
35
42
49
55
62
70
1130 1480 1480 1490 1840 2190 2190 2190 2190 2190 2190
1180 1180 1530 1530 1530 1880 2230 2230 2230 2230 2230 2230
449
570
700
827
1207 1424 1645 2024 2281 2552 2823 3064
Length
1890 2065 2240 2415 2765 2765 2940 3290 3465 3640 3640 3815 3990 3990 3990
Weight2)
221
Length
Weight
2)
265
360
471
592
722
849
1237 1454 1675 2054 2311 2582 2853 3124
2335 2510 2705 2880 3230 3230 3405 3765 3940 4115
276
326
441
592
735
903
4115 4290 4465 4465 4465
1053 1499 1755 2028 2441 2733 3040 3347 3654
Length
2415 2590 2765 2940 3290 3290 3465 3815 3990 4165 4165 4340 4515 4515 4515
Weight2)
295
354
469
620
763
931
2
3
5
8
11
15
Width
760
760
1130
Height1)
1170 1520 1560 2260 2260 2960 2960 2980 3680 4380 4380 4380 4380 4380 4380
1081 1535 1808 2080 2494 2786 3093 3400 3707
SIZE
Panel 25
Panel 50
S3V
Panel
25
Panel
50
S4V
Panel
25
Panel
50
23
29
42
49
55
62
70
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
810
Height1)
1270 1620 1660 2360 2360 3060 3060 3060 3760 4460 4460 4460 4460 4460 4460
Length
1810 1985 2180 2355 2705 2705 2880 3240 3415 3590 3590 3765 3940 3940 3940
Weight2)
333
Length
1890 2065 2240 2415 2765 2765 2940 3290 3465 3640 3640 3815 3990 3990 3990
Weight
357
393
430
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
555
592
740
777
946
983
1147 1362 1969 2311 2678 3359 3804 4271 4758 5192
1184 1399 2019 2381 2748 3428 3874 4347 4828 5309
Length
2335 2510 2705 2880 3230 3230 3405 3765 3940 4115
Weight2)
402
Length
2415 2590 2765 2940 3290 3290 3465 3815 3990 4165 4165 4340 4515 4515 4515
Weight
2)
431
476
519
658
701
883
926
1111
4115 4290 4465 4465 4465
1350 1588 2261 2642 3061 3776 4256 4759 5282 5782
1154 1393 1631 2317 2735 3153 3868 4349 4858 5375 5892
Dimensions in mm. Weights in kg.
1)
Does not include the height of the metal frame. 2) Does not include the weight of the metal frame.
32 | AHU NB
35
Width
2)
810
18
SIZE
UNITS WITH MIXING SECTION
2
3
5
Width
760
760
1130
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
Height1)
585
760
780
1130
Width
810
810
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
Height1)
635
810
830
Length
1810 1985 2180 2355 2705 2705 2880 3240 3415 3765 3940 4115 4290 4290 4290
Weight2)
215
Panel 25
Panel 50
M1V
Panel
25
Panel
50
M2V
Panel
25
Panel
50
M3V
Panel
25
Panel
50
M4V
Panel
25
Panel
50
254
361
8
11
15
18
23
29
35
42
49
55
62
70
1130 1480 1480 1490 1840 2190 2190 2190 2190 2190 2190
1180 1180 1530 1530 1530 1880 2230 2230 2230 2230 2230 2230
467
606
729
862
1273 1469 1716 2135 2403 2685 2967 3234
Length
1890 2065 2240 2415 2765 2765 2940 3290 3465 3815 3990 4165 4340 4340 4340
Weight2)
229
Length
2335 2510 2705 2880 3230 3230 3405 3765 3940 4290 4465 4640 4815 4815 4815
Weight2)
283
Length
2415 2590 2765 2940 3290 3290 3465 3815 3990 4340 4515 4690 4865 4865 4865
Weight2)
303
Length
2685 3210 3580 3930 4630 4630 4980 5690 6390 6740 7090 7790 8140 8140 8140
Weight2)
339
Length
2765 3290 3640 3990 4690 4690 5040 5740 6440 6790 7140 7840 8190 8190 8190
Weight2)
362
Length
3150 3675 4025 4375 5075 5075 5425 6125 6825 7175 7525 8225 8575 8575 8575
Weight2)
408
Length
3290 3815 4165 4515 5215 5215 5565 6265 6965 7315 7665 8365 8715 8715 8715
Weight2)
436
533
715
916
2
3
5
8
Width
760
760
1130
Height1)
1170 1520 1560 2260 2260 2960 2960 2980 3680 4380 4380 4380 4380 4380 4380
276
341
372
416
445
499
383
472
493
512
606
617
489
610
638
734
766
877
628
765
799
960
751
920
960
884
1304 1514
1761 2180 2448 2730 3012 3294
1069 1564 1823 2115 2557 2852 3178 3497 3816
1116 1603 1868 2167 2620 2922 3241 3560 3879
1138 1347 2037 2403 2767 3513 4013 4495 4822 5149
1003 1188 1405 2087 2462 2835 3599 4111 4605 5177 5504
1124 1338 1569 2329 2748 3163 3942 4477 4944 5323 5650
1175 1396 1637 2410 2816 3241 4039 4586 5117 5464 5791
SIZE
Panel 25
Panel 50
M5V
Panel
25
Panel
50
M6V
Panel
25
Panel
50
15
18
23
29
35
42
49
55
62
70
1130 1480 1480 1830 2190 2190 2190 2540 2890 3240 3590 3940
Width
810
Height1)
1270 1620 1660 2360 2360 3060 3060 3060 3760 4460 4460 4460 4460 4460 4460
Length
1810 1985 2180 2355 2705 2705 2880 3240 3415 3765 3940 4115 4290 4290 4290
Weight2)
339
Length
1890 2065 2240 2415 2765 2765 2940 3290 3465 3815 3990 4165 4340 4340 4340
Weight
2)
362
810
11
416
445
1180 1180 1530 1530 1880 2230 2230 2230 2590 2920 3290 3620 3990
512
606
734
766
960
1138 1347 2037 2403 2767 3513 4013 4495 4822 5149
1003 1188 1405 2087 2462 2835 3599 4111 4605 5177 5504
Length
2335 2510 2705 2880 3230 3230 3405 3765 3940 4290 4465 4640 4815 4815 4815
Weight2)
408
Length
2415 2590 2765 2940 3290 3290 3465 3815 3990 4340 4515 4690 4865 4865 4865
Weight
2)
436
499
534
617
715
878
916
1124 1338 1569 2329 2748 3163 3942 4477 4944 5323 5650
1175 1396 1637 2170 2816 3241 4039 4586 5117 5464 5791
Dimensions in mm. Weights in kg.
1)
Does not include the height of the metal frame. 2) Does not include the weight of the metal frame.
AHU NB | 33
Sections in detail
Air filters
The standardised range for the NB Air
L _ sections which, combined with the wide
$
% & Particle size is expressed in microns (10-6 m). Air contains
particles with a thickness of up to 0.01 microns and other
particles with a thickness similar to fibres, leaves, etc.
Dust is generally understood to mean particles under
100 microns.
34 | AHU NB
99,90
99,00
1)
95,00
r(
be
m
90,00
Nu
80,00
70,00
60,00
50,00
40,00
30,00
)
ce
(2
fa
ur
S
3)
20,00
t(
Atmospheric dust is a mixture of fog, combustion gases, fine
dry particles and fibres. Air testing normally indicates the
presence of soot and smoke, quartz, soil, residue from
decomposed animals and vegetables, organic substances in
the form of cotton and plant fibres, and metal fragments. The
air also contains other organisms such as microorganisms,
spores and pollen.
99,99
gh
The air contains numerous foreign substances caused by
natural processes (e.g., wind erosion, sea evaporation, soil
movements, volcanic eruptions) and by human activity (e.g.,
combustion).
10,00
ei
The various impurities that can exist in the air are discussed
below.
The upper curve indicates (in % of total) the number of
suspended particles in the air with a diameter below a certain
reference number (e.g., 99.9% are below 1 micron)..
W
Air filtering is related to the quantity, variety and size of the
suspended impurities, the existence of contaminant gases or
odours, and the desired filtering efficiency.
The particle size distribution of particles in atmospheric dust
can be measured in one of several ways. The following figure
contains three curves representing the distribution of particles
according to number, weight or spray surface.
PERCENTAGE < DIAMETER OF PARTICLES
One of the purposes of the air handling unit is to ensure the
purity of the room air.
5,00
1,00
0,10
0,01
0,01
0,1
1
DIAMETER OF PARTICLES
10
20 μm
The middle curve shows the particle spray distribution on the
surface; for example, the surface sprayed with particles under
1 micron, account for 30% of the total weight of the particles.
The lower curve indicates the distribution by weight of
atmospheric dust; for example, particles below 1 micron
account for 30% of the total weight of the particles.
Traditionally, a variety of measurement methods have been
used to determine the efficiency of the different types of
filters and no classification system combining the various
criteria in use existed. The first version of the Unified Standard
EN 779 was issued to unify the classification criteria for all
filters with an initial efficiency with atmospheric dust less than
or equal to 98%, (Group G: coarsedust filters; Group F:
fine-dust filters).
Its advantages with respect to flat filters are:
Greater filtering surface;
Reduced front air velocity;
Greater efficiency;
Greater dust retention capacity;
Reduced front surface.
The filters correspond to Classes G1, G2, G3 and G4 of Group G
(coarse-dust filters) and Class F5, F6 and F7 for Group F
(fine-dust filters), as per UNE-EN 779.
Later, in 1998 the first version of Unified Standard EN-1822
unifying the classification criteria for HEPA and ULPA absolute
filters was published. The initial efficiency of these filters with
atmospheric dust is greater than 98%..
Extended surface filters
Characterised by a specific type of pleat which produces a
larger filtering surface. The pleat design, as well as the
alignment between the pleats, ensures uniform air circulation
over the surface of the filtering media.
The extended surface filter is composed of a frame, filtering
media in zigzag layout, and electrowelded mesh to hold the
media.
Flexible bag filters
Which allow a high filtering flow rate in relation to the front
surface area. Constructed with fibreglass (greater efficiency) or
synthetic fibre (lower efficiency) filtering media.
This equipment has the following advantages:
Lower power requirement.
Longer filter renewal interval.
Lower energy costs.
Lower maintenance.
These filters have a medium to high efficiency and correspond
to Classes F5, F6, F7 and F8 of Group F (fine-dust filters) as
per UNE-EN 779.
Panel filters.
Bag filters.
AHU NB | 35
Rigid bag filters
Same as above but allowing a high filtering flow in relation to
the front surface area.
This equipment has the following advantages:
Solid, sturdy construction for fast, easy installation.
Compact, reduced-volume design.
They have a medium to high efficiency and correspond to
Classes F5, F6, F7, F8 and F9 of Group F (fine-dust filters) as
per UNE-EN 779.
Both the rigid and the flexible bag filters are specially
recommended for:
Hospitals.
Pharmaceutical companies.
Food industries.
Computer rooms.
Office buildings.
Likewise, both rigid bag filters and the flexible bag filters of
Class F8 and F9 trap particles below 6 microns, which
correspond to the smallest particles of those in temporary
suspension that are visible under a microscopic.
Rigid filter.
Absolute filters
Require careful installation that guarantees complete airtightness of all gaskets. They are designed to eliminate
virtually even the smallest particles in the air, i.e., those in
continuous suspension (the smallest of these are only visible
using electronic microscopes).
They are specially recommended for:
Hospitals.
Food industries.
Pharmaceutical companies.
Clean rooms.
Absolute filtering of air in environments with controlled
contamination.
They should be installed immediately before the space
requiring this virtually sterile air that these filters can supply.
They correspond to Classes H10, H11, H12, H13 and H14 of
Group H: absolute filter, HEPA and ULPA, as per UNE-EN 1822.
36 | AHU NB
CHARACTERISTICS OF THE MAIN ATMOSPHERIC POLLUTANTS
Continuous suspension particles
Temporal suspension particles
SMOG
Thick particles
FOG
TABACCO SMOKE
DRIZZLE
ATMOSPHERIC DUST AND ASHES
VIRUS
BACTERIAS
RAIN
INDUSTRIAL DUST
POLLEN
Human
Air
FUEL SMOKE
Visible under electric microsc.
COAL SMOKE
Visible under the microscope
ELECTROSTATIC FILTRATION
Visible under the human eye
NORMAL FILTRATION
ø particles
0,1
1
10
Drop Speed
0,000035
0,0035
0,296
CO
CO
100 000
350
10 000
35
1 000
100
29,6
AIR PURITY CONDITIONS IN CLEAN ROOMS
S
3 500
U
S
TY
PE
Particles per litre
0,35
Particles per cubic foot
TY
3,5
CYCLONES
PE
100
10
S
1 000
MICRAS
395
cm/s
S
209 a
10
00
3 5 00
00
00
0
35
0
TY
PE
10
0
35
*10
0,05
1
5
10
50
100
PARTICLE SIZE (Micras)
* Counts below 10 particles per cubic foot (0.35 per litre) are dubious.
Example: admissible particles for a Class 10,000 system:
10.000
per cubic foot, 0,5 microns.
1.200
per cubic foot, 1 micron.
70
per cubic foot, 1 micron.
AHU NB | 37
Sections in detail
Heating/cooling units
Copper tube and aluminium fin heating/
cooling units
This class of heating/cooling unit is most commonly installed in
air handling units, and is composed of a coil of copper pipes
covered with thin aluminium fins to greatly increase the
primary heat transfer surface of the tube, due to the large
transfer surface of the fins.
The front air velocity surface (Afo) expressed in m 2 is
determined by the dimensions (width x height) of the air
handling unit internally.
Since the vertical spacing between the heating/cooling
& & L=J ‡#$
NB-70 air handling unit model has a specific number of tubes
based on its working height, defined in the heating/cooling
code as “T”.
The maximum horizontal length of the finned coil is
determined by the working width of the interior of the air
handling unit and expressed in mm.
The depth of the heating/cooling unit is composed of a specific
number of rows of tubes facing the direction of air flow. The
number of rows is calculated according to the air flow
conditions at the inlet and outlet of the unit, based on the
cooling or heating energy used by the equipment.
The number of rows is defined by a number, followed by the
letter “R”.
Based on the above, a unit designated as 20T 3R 950 means:
20 T Height of 20 tubes, equal to 1200 mm;
3 R Depth of three tubes, at a distance of 30 mm;
950 Length of finned coil, in mm.
The standardised NB Air Handling Unit range uses the
following heating/cooling units:
This range can be used with any cooling or heating fluid except
steam, where the length of the finned coil is slightly lower, since
collectors must be mounted on both sides of the unit instead of
one side only, as normally done with other fluids.
Air Handling Unit Model
Quantity of tubes
Quantity of ranges
Lenght in mm
NB-2
6
1 to 10
500
NB-3
10
1 to 10
500
NB-5
10
1 to 10
850
NB-8
16
1 to 10
850
NB-11
16
1 to 10
1.200
NB-15
20
1 to 10
1.200
NB-18
20
1 to 10
1.500
NB-23
20
1 to 10
1.850
NB-29
26
1 to 10
1.850
NB-35
32
1 to 10
1.850
NB-42
32
1 to 10
2.200
NB-49
32
1 to 10
2.550
NB-55
32
1 to 10
2.900
NB-62
32
1 to 10
3.250
NB-70
32
1 to 10
3.600
38 | AHU NB
Selection of the air velocity through the
heating/cooling unit
Normally, the air velocity through the heating/cooling unit should
not exceed 2.7 m/s (not including the drop separator), as this
velocity is considered the maximum admissible to prevent
entrainment of condensed water to other sections of the air
handling unit or from the air supply system to the environments.
The heating/cooling unit will also provide good efficiency levels
at lower velocities, however. As a result, since the pressure drop
of the air flowing through the unit is lower, both the static
pressure of the fan and the input power are also lower.
In terms of energy, this factor can save on power consumption
over the years. Moreover, when the fan is selected, the rotating
speed of the fan can be lowered to reduce the noise level.
In some cases the above factors are critical and can be solved
by selecting an air velocity through the heating/cooling unit
below 2.7 m/s.
In the case of air handling units with heating units only (one or
more), the air velocity may be above 2.7 m/s, although in
terms of energy consumption and the above considerations,
the circumstances are the same.
Generally the flow velocity is 3.5 m/s.
For heating, the use of units with steel pipe is recommended
when utilising fluids at high temperature and pressure, as
these pipes are much stronger than copper pipes, which could
be deformed under these conditions due to excessive
expansion of the metal.
AHU NB | 39
Sections in detail
Humidifiers
Panel humidifier
Below the panel, there is a water pan with level control and a
motorised pump to drain water to the discharge collector.
The evaporative humidifier, which is also used as an air cooler,
can treat large air volumes to obtain cold, humid air at very
low cost.
Common applications include localised cooling at job stations,
ventilation and heat dissipation in machine rooms, laundries, large
kitchens, warehouses, manufacturing plants, as well as providing
moisture to print shops, textile plants and greenhouses.
Its main advantage when included in a ventilation system is
that it requires lower air flow in circulation due to its cooling
effects. This is extremely important for human comfort.
The humidifier essentially consists of a component that is in
close contact with water and is swept by an air current,
producing rapid water evaporation. The water is added to the
air and cooled by an evaporation process.
The evaporated water is replaced through a float valve.
Humidifier application
Humidification means that water vapour is added to the air.
The humidification component contains multiple channelled
plates joined together to form a block and arranged so the air
flows horizontally and the water falls vertically over the plates.
Water is distributed at the top of the panel by a collector tube
with water outlets.
The amount of humidification can be expressed as the
moisture content (g of moisture per kg of dry air) or the
relative humidity (moisture content under specific conditions of
air with respect to the maximum saturation content at the
same temperature).
When the air is heated, the amount of water vapour it can
hold is increased.
If no moisture is added to the air, the humidity level remains
constant and the relative humidity decreases.
In other words, the air will be drier, absorbing moisture from
the objects with which it comes in contact (e.g., walls,
furniture, products, etc. and more importantly, the body).
During the winter, adequate humidification slows evaporation
from the body, increasing personal comfort, even at lower
temperatures than normal.
Furniture, tools and sensitive equipment benefit from this
situation, as it is extremely important to avoid static energy
that is caused by low relative humidity and interferes with
phone and electronic equipment.
Hospital environments must have adequately controlled relative
humidity, since an excessively dry atmosphere may lead to
bacteria growth and weaken the body’s immune system.
40 | AHU NB
In order to calculate the humidifier’s efficiency, use the
following formula to determine the saturation efficiency (SE):
Where:
Tse = dry temperature of inlet air.
Tss = dry temperature of outlet air.
Th = wet-bulb temperature of air.
Based on the psychrometric chart (a diagram is shown on
this page), air with inlet conditions of 38º C (Tse) and 21º C
(T h) is converted in the humidifier finding the process at the
wet-bulb line of 21º C until reaching an outlet temperature of
24º C (Tss).
The saturation efficiency will be:
This percentage is reasonable, since the maximum level that
can be expected from this type of humidifier is 90%, as shown
in actual practice.
When this example is applied to a specific case in which an air
flow of 30000 m3/h, is circulating and the moisture content of
the air at the inlet (xe) is 8.6 g/kg and at the output (xs) is
14.4 g/kg, then the amount of moisture added is:
AHU NB | 41
Air cooler application
Water spray humidifier
The above example shows that this type of panel may be used
as a cooling medium, since its behaviour is typical of an
adiabatic cooling or constant enthalpy process.
The same considerations used for the panel humidifier are
applicable in the case of water spray humidifiers, also known
as air scrubbers.
Based on the above data, when heat dissipation of 200,000,
kcal/h is needed in a space where the inside temperature
should be maintained at no more than 29ºC, it is possible to
calculate the air flow that should be introduced and therefore
also removed from the local.
This is an air handling unit section which houses a series of
water sprays which produce very small particles that come
into contact with the circulating air flow and produce a high
level of evaporation.
The air flow required will be:
The bottom of this section contains a drip pan, from which
water is sent back to the sprays, with only evaporated water
added back to the system.
The system requires the use of a water circulation motor
pump, which is not normally included in the supply of this
section. A price quote may be provided, however, upon
request.
To prevent the entrainment of water particles, this type of
humidifier is always equipped with a drip separator at the air
outlet as a safety measure.
The most appropriate air velocity in this type of humidifier is
2.7 m/s, and the water flow circulated by the spray bank is 0.8
l per m3/h of air.
Water spraying can be done either in the same or the opposite
direction of air flow, resulting in different saturation
efficiencies.
The use of multiple units also increases efficiency, with the
following experimental results obtained:
One unit only, same direction as air flow
60% efficiency;
One unit only, opposite direction as air flow 75% efficiency;
Dual unit, same direction as air flow
84% efficiency;
Dual unit, one in same
and one in opposite direction
90% efficiency;
Dual unit, opposite direction to air flow
95% efficiency.
Sections with a dual unit are longer, and when spraying is
opposite to the direction of air flow, a drip separator is located
at the inlet for the section.
The examples indicated earlier for the panel humidifier, are
also useful for this type of humidifier.
SENSE OF THE AIR
Selection of the most appropiate fan is mainly influenced by
the static pressure considered.
42 | AHU NB
Depending on the type of air conditioning system, different
static pressures are used (commonly known as low, medium or
high).
Low pressures are considered to those up to 90 mm w.g,
medium pressure is up to 180 mm w.g. and high pressure is up
300 mm w.g.
Sections in detail
Fans
Centrifugal
The NB series has three types of fans that cover all needs: the
AT and ADH models for low pressures and the RDH model for
medium and high pressures.
However, since the RDH model is a fan equipped with a rotor
having backward curved blades (more efficient than the AT
and ADH models, which have forward curved blades), it may
also be used for low pressures. This will increase equipment
performance, although the initial price of the air handling unit
will be higher.
In addition to the above, when the electric motor is selected,
the input power at the shaft must be multiplied by the
following coefficients:
Coefficient to be used
ADH
RDH
1,25
1,25
1,20
1,15
1,15
1,12
0,75
kw
)
Poteje
0,75
kw
Poteje
10 kw
Poteje
*
10 kw
Once the new value is obtained, compare it to the
standardised values from the electric motor manufacturers.
The energy of the electric motor used to operate the fan is
dissipated in the circulating air, and therefore affects the
cooling load of the cooling system.
In many cases, the air flow necessary for heating may be
considerably less than for cooling. In this case, a two speed
motor can be used. This changes the fan characteristics,
minimising air flow during the winter season.
There are practically no limits for low-temperature operation in
the fan section. In contrast, high temperatures can damage the
motor. These temperature limits are clearly defined by electric
motor manufacturers and must be respected to at all times.
! " Due to the efforts made to decrease energy costs, this fact
should not be disregarded and the potential energy savings
should be calculated, then compared with the depreciation
schedule for the investment. In many cases, the result is highly
satisfactory.
Once the fan model is selected, check the respective
behaviour curve to obtain the unique characteristics.
Based on two essential factors (air flow and total static
pressure), the following is obtained:
Revolutions per minute
Efficiency, in %
Input power at the shaft, in kW;
Mean sound power level of the octave bands, in dB;
Air outlet velocity, in m/s;
Dynamic pressure, in mm w.g.
Peripheral velocity, in m/s.
#! " AHU NB | 43
Plug Fan
Plug fan built into an acoustically insulated air handling unit.
A plug fan supplies air at the fan section outlet with a low and
even air speed. In certain situations it can, therefore, be an
advantage to position air handling components on the outlet
side of the fan.
Single inlet plug fan with open outlet into the air handling unit.
The fan impeller is fitted directly to the motor shaft. This fan
type has low sound power levels in the lower frequencies.
Efficiency up to 75%.
The motor is supplied with a 1-speed motor. In order to regulate
the fan speed to its actual operating point the motor must be
fitted with a frequency converter.
The frequency converter can continuously control the fan speed
and airflow. Power consumption can be greatly reduced by
operating the fan at lower speed.
Operating temperatures:
’Y„#“”Œ#•
’Y#“”‡#•
All fans are fully balanced both statically and dynamically.
The fan and motor are built on a stable base frame that is
connected to the unit casing with rubber vibration isolators.
These are designed for high levels of vibration absorption.
The fan inlet is flexible connected to the unit casing. This
ensures a good vibration absorption.
44 | AHU NB
NB Selection Program
+^< – — ˜™–$= W7, provided the equipment meets the following minimum
requirements:
Intel® Pentium® III or compatible processor;
1 GB of RAM;
500 MB of space on the hard disk;
\=\ š
=J„#†Œ%{‡›\ š
Mouse;
Regional configuration and keyboard.
This program is specially designed to allow the selection of
NB Air Handling Units and will help you to:
Develop new projects according to your needs, readily
making all the calculations necessary ;
Divide the equipment into modules, in accordance with the
project requirements;
Easily save, retrieve and modify all your projects;
Create a scale drawing of the equipment selected, allowing
hard copies to be made;
Obtain all technical information for the equipment selected,
including the curves for the selected fan and its operating
point;
Estimate the cost of the equipment.
The NB Selection Program is user-friendly and highly intuitive.
AHU NB | 45
Applicable regulations and Quality
The Normabloc Air Handling Units comply with the following EC Directives:
2006/42/CE
Machinery Directive
2004/108/CE
Electromagnetic Compatibility Directive
2006/95/CE
œ= \ and with the following harmonized technical standards:
UNE-EN 12100-1
Safety of machines. Basic concepts. General principles of design Part 1.
Basic Terminology. Methodology
UNE-EN 12100-2
Safety of machines. Basic concepts. General principles of design Part 2.
Principles and technical specifications.
UNE-EN 294
Safety of machines. Safety distances to prevent upper limbs from reaching
danger zones.
UNE-EN 60204-1
Safety of machines. Electrical equipment of machines. Part 1: general
requirements.
UNE-EN 1050
Safety of machines. Principles for risk assessment.
UNE-EN 1886
= & 46 | AHU NB
J [ UNE 1886: 1999 / 2007
1999
2007
STRENGTH OF THE CASING
2A
D1
MECHANICAL TIGHTNESS
B
L2
FILTER BY PASS LEAKAGE
F9
F9
THERMAL TRANSMITTANCE OF THE CASING
T4
T4
THERMAL BRIDGING
TB3
TB3
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M1
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Technical Assistance Service
Systemair HVAC Spain S.L.U. makes
available to all customers of a Technical Assistance
Service (TAS) and highly qualified with over 30 years
of industry experience, specializing in both
Industrial facilities as of Comfort, for the
resolution of any questions you may
present.
We also offer a service of
commissioning and technical
advice of the equipment
supplied, valued customer so
please contact us and request
a quote without any
commitment on such services,
which provide the final work of
the installer.
www.systemair.es
+34 91 600 29 00
AHU NB | 47
C/Montecarlo, 14
28942 Fuenlabrada (Madrid)
Spain
Teléfono: +34 91 600 29 00
Fax: +34 91 600 29 08
www.systemair.es
10/2011
"#