The CTA Air Handling Units are manufactured with bearing framework and sandwich paneling.
The frame is made of extruded anticorodal aluminium alloy profiles, usually of type AlMgSi 0,5- UNI 9006/1.
NOVAIR EXCLUSIVE PROFILE
The exclusive bearing structure made by NOVAIR, having actual dimensions of 37 x 25 mm and 62 x 50 mm, uses the lock panel system in aluminium (snap-in).
Its patented system permits to reach paneling tightnesses beyond 2500 Pa (10 inWG) (class B), because of the homogeneity of the pressure over the paneling perimeter, not achievable with the traditional system (self-drilling screw fastening).
This profile doesn’t require the aid of internal and external screws, giving therefore a solider and aesthetically more pleasant appearance. Because of the dimensions of the profile, the used panel will have actual dimensions of 25/50 mm (the only
size available for snap-in). The profile hasn’t got external sharp edges, as foreseen by the safety and accident-prevention rules in force.
• frame made of anodized anticorodal aluminium alloy
• frame with Thermal Break profile 60 x 48 mm.
This profile is used when the environmental conditions and the type of handling can cause moisture on outside surface.
• sandwich panels with skins made of: galvanized steel, plastified galvanized steel sheet, peraluman, stainless steel as per specifications hereinafter
• insulation with mineral wool density 80 - 100 kg/m3
• panels fastening: by stainless steel screws (thermal break profile)
On request each unit can be equipped with the following accessories:
• sound insulation
• side technical boxes, made of 25 mm thick sandwich panels, without bottom panel, for housing of hydraulic, electrical and other components.
• return or exhaust grid with protection net made of galvanized steel sheet, painted galvanized steel sheet or aluminium
• anti-vibration joints installed outside the units on the fan outlets to be connected to ducts
• pressure connections
• dial or liquid type differential manometers or differential pressure - gauges, monted and connected to the pressure pipes
• double chamber plexiglass porthole in the inspectionable sections
• light fixture with tight ceiling lamp IP 55, 24 V and IP 65 feed
• lamp/s wiring with outside switch
• motor wiring with electric disconnecting switch
The paneling is double skin sandwich type made of galvanized sheet, with insulation polyurethane foam of minimum density 45 kg/m3, actual thickness:
- 25 mm up to CTA 130
- 45 mm up to CTA 800 for Thermal Break units
- 50 mm up to CTA 800
- 63 mm up to CTA 800, for Hygenic version (SANIX)
Standard panels are made as follows:
INNER SKIN: hot dipped galvanized sheet (galvanization not less than 140 g/m2), 5/10 mm thick.
INSULATION: rigid polyurethane foam minimum density 45 kg/m3, thermal conductivity 0,018 ÷ 0,024 W/m2°C.
OUTSIDE SKIN: hot dipped prepainted sheet, 6/10 mm thick.
The physical characteristics of the panel so manufactured are the following:
- thermal transmittance factor: 0,45 - 0,49 W/m2°C
- fire reaction: class 1
The fastening of panels on the bearing structure is done with a SNAP-IN system or with galvanized/INOX steel screws for Thermal Break profile.
The bearing baseframe is made of galvanized steel with pressure bent, bolted or welded profile, according to the configuration of the unit. It is arranged for the sections lifting and suitable for water piping passage and drain.
The basements of all the above solutions are made of galvanized steel sheet with minimum thickness 20/10 mm.
On request basements or support feet can be supplied with different shapes, dimensions and materials.
The units that have to be installed outside or anyway exposed to weathering are supplied with covering roof, as accessory element.
NOVAIR can propose different solutions, according to the requests or to actual needs:
- flat hot dipped galvanized sheet
- flat peraluman sheet minimum thickness 15/10 mm or greek-folded.
When it is necessary to reduce the propagation of the sound wave coming from the unit through the air ducts, we suggest the following additional internal coating, which are different in type and sound absorption:
- microstretched galvanized sheet + mineral wool, density 80-100 Kg/m3, covered with an antiscaling film. Minimum thickness 25-50 mm. (Non washable material)
ACCESS AND INSPECTION DOORS
Inspection doors on Air Handling units allow the access and inspection while assuring an easy opening and sure airtightness. Standard width is 460-600 mm.
SECTIONS UNDER NEGATIVE PRESSURE:
Doors are fastened to the frame with hinges and handles made of nylon weighted with fiberglass, of NOVAIR design, allowing an easy opening even from the inside of sections.
SECTIONS UNDER POSITIVE PRESSURE: Inspections are equipped with traverse bars made of stainless steel whose closing is made by locking knobs (hinges are not used) assuring a uniform pressure of the door on the frame gasket. On demand it’s possible to mount hinged type access doors with inward opening.
Each access to fan section is usually equipped with the following safety devices:
- safety net
- microswitch 24 V feed
- internal earthing cable
Dampers are made of extruded anticorodal aluminium with aerofoil blades and gasket.
The movement is opposed type and is made by ABS gears protected from the airflow. Dampers are usually supplied with motorizeable pivot.
On request the actuator can be of manual type.
• working temperature limit 80 °C, compatibly with the resistance of the other internal components of the unit
• dampers up to length 1.200 mm in single piece, for bigger dimensions blades are splitted in two, with middle divider
• air crossing speed:
- return and exhaust dampers: 4 ÷ 6 m/s (787÷1181 fpm)
• dampers installed on fan outlets are made of galvanized iron with aerofoil drum blades and, according to the air volume, equipped with spacer stub pipe.
• when required by dimensions, the dampers are equipped with two connected pivots reducing the opening effort.
• from size CTA 260 the installation of dampers is made inside the unit.
• dampers with galvanized steel frame and aerofoil blades, opposed or parallel movement obtained by levers installed out of the airflow
• overpressure dampers with galvanized steel frame and aluminium blades with pitch 50 or 100 mm. These type of dampers are suitable either for exhaust or air inlet assuring the gravity closing at the flow stop.
Grids are made of galvanized steel or aluminium with fixed inclined horizontal fins against rain. The grid can be directly fastened to the damper installing a containing stub pipe between them, or directly fastened on the panel.
Grids are available with 50 or 60 mm fins spacing and are all equipped with metallic birdscreen.
• rectangular supply and return flanges.
• closing panel on return section for units up to size CTA 76 included.
THERMAL EXCHANGE SECTIONS
These modular sections are manufactured in order to house the coils for thermal exchange between the air and the heating and/or cooling fluid.
The sections are equipped with galvanized steel sheet guides allowing the introductionof the coil and its removal from both sides of the AHU.
A galvanized steel sheet or, on request, AISI 304 (AISI 316) stainless steel drain pan is foreseen for cooling and dehumidification handlings, insulated by an anti - condesation pad.
- Pre-heating coil: iits main aim is to pre-heat the air or, more frequently,
to make humidification possible up to the requested values. Their standard execution has copper tubes and packed aluminium fins.
- Cooling and dehumidification coils: the aim of this type of coil is to handle the air removing from it the sensible and latent heat, making it suitable to balance the room thermal loads. Their standard execution has copper tubes and packed
- Post-heating coils: they are used in all the plants where a fine control
on temperature and relative humidity is required. Construction features are similar to pre-heating coils.
INTEGRATED REGULATION SYSTEM
The air handling units can be provided with integrated regulation system, that includes a power supply electrical panel, fully wired and tested in factory. The unit only requires on-site electrical and hydraulic connections.
The microprocessor installed in the unit, allows many air handling unit configuration types. The system manages a number of elements and devices such as supply and return fans, temperature, humidity, hot and cold liquid heat exchangers electric heaters, dampers and energy recovery devices in all their possible applications.