Airmax II DX - Unit cooler0 pages

Airmax II
Application
This new range of industrial unit coolers has been designed
using the well-known Airmax technology, which has become a
standard for all installers and end users.
Airmax II is available as a direct expansion evaporator (DX) for
all HFCs as well as water/glycol unit coolers.
This new industrial line is designed to keep fresh and frozen
goods refrigerated from +30 to -40°C, with a high or low
humidity content.
Thanks to a wide capacity range (from 5 to 180 kW), which can
be achieved using several coil combinations, fan diameters
(up to 800mm), different fin spacing and a long list of options,
Alfa Laval can fulfil every requirement with more than 200
standard models.
Standard design
Coil
The heat exchanger is designed to achieve optimal capacity
thanks to the staggered pitch rows that give a high secondary
fin surface. The large fin surface ensures longer intervals
between defrost cycles, therefore reducing the amount of daily
energy used.
The coils are manufactured with a special aluminium fin array
and have a high efficiency internal copper tube with a grooved
inner wall with 12 mm nominal bore. All this allows for a minimal
internal volume with the advantage of using less refrigerant.
Frame and Casing
All units are manufactured using galvanised steel, zinc–coated
and finished in corrosive-resistant RAL, except the drip tray
which is aluminium coated.
The frame has been designed to ensure easy installation and
maintenance. A large, deep drip tray allows fast discharge of
defrost water and the hinge fastening allows for easy maintenance.
The supports have two different positions (ceiling or
space) to enable installation of the water defrost cassette.
Structural parts are fastened with stainless steel bolts and
screws. Structures are made in galvanised steel with optimised
length to enable uniform air suction in the coil.
All panels such as the drip tray end covers are hinged for
easier accessibility, making installation, servicing and maintenance
easier than for other standard unit coolers.
Fans
Air suction fans are available in four different fan diameters:
500, 560, 630 and 800 mm, with a 2-speed, three-phase
motor (Ä/Y) 400V 50Hz. The motors have a dynamically and
statically balanced external rotor and are manufactured in
accordance with VDE 0530/12.84 IP54 class F.
Integrated thermo contacts (Clikson), provide reliable protection
against thermal overload.
All standard motors can work at temperatures down to
-40°C. Special lubrification is available on request.
R&D has developed the air flow distribution in order to give
a uniform air velocity in the coil with:
• High efficiency sickle blade
• Better distribution in cold rooms
• Reduced noise levels
• Increased air throw
Water/glycol
For water/glycol applications, the coil is designed with same
fin pattern and smooth 5/8” copper tube. All connections are
thread connections with vent and drain plug as standard.
All other characteristics are the same as for the Airmax II DX.
Test
Each DX heat exchanger undergoes a pressure and leak test
with dry air at 31 bar, and is finally supplied with a nitrogen
pre-charge, while the water/glycol is tested at 11 bar.
Unit cooler
Airmax II DX