7
2.2 Fans
The ComfoAir XL series consists of directly driven,
energy-saving EC fans with backward-curved blades.
These fans achieve an energy saving of more than
25 % compared to conventional AC fans. These fans
are mounted vibration-free onto a mounting bracket.
This obviates the need for flexible sleeves to ensure
a vibration-free connection of the air ducts.
Error message
An alarm function is included in the control board as
standard. This alarm function is activated if a fan
fails. The error message can also be activated by
measuring the pressure difference via the supply air
filter if desired.
2.3 High-performance plate heat
exchanger
The HR cross-counterflow heat exchanger (HR plate
heat exchanger) is made of high-grade aluminium
and has a thermal efficiency of approx. 90 %
depending on the outside temperature and the air
humidity in the rooms. The exchanger is corrosion-
free and resistant to seawater and can be fully
recycled.
Benefits of a high-performance plate heat exchanger:
■
No wear
■
Easy to maintain
■
100 % separate air streams
■
Low risk of contamination
Extract
air
Supply air
Exhaust
air
Outside air
Frost protection
Under certain circumstances, condensate can freeze.
To prevent this, frost protection is incorporated. This
shuts down the supply fan when there is a risk of
frost and can deactivate it for a short period.
2.4 Siphon
A siphon is installed to remove condensate that
forms in the plate heat exchanger.
An external diaphragm siphon must be connected to
remove the condensate that forms on the cooler. The
siphon can be kept frost-free by using an insulated
ribbon heating element. The contact for supply and
control can be set in the software.
2.5 Bypass
ComfoAir XL is equipped with a 100 % bypass. The
control unit of the ComfoAir XL automatically brings
the bypass valve to the closed and open positions.
This bypass is located near the heat exchanger and
is controlled by a counter-rotating bypass valve,
which is controlled automatically by a servo motor.
When the bypass valve opens, the extract air flows
around the high-performance plate heat exchanger
and no thermal transfer takes place. The filter system
continues to work, however. In this way, it is possible
to use what is referred to as 'free cooling' or night
ventilation in the evening and during the night.
Please also refer to the block diagram in chapter 1,
section 4 for details of bypass operation.
Open/closed or modulating bypass
ComfoAir XL can be equipped with an open/closed
or modulating bypass. The servomotor regulates the
modulating bypass and ensures that the temperature
of the supply air is constant. This is particularly
important when the unit has a cooling battery.
2.6 Filter
Two types of filters are available for filtering the
supply and exhaust air flows: one cellular filter and a
bag filter. The supply air flow is equipped with a F7
filter as standard, the exhaust air flow is equipped
with a G4 filter. With the newly developed filter
clamps, the filters are mounted onto the filter frame,
which minimises leaks. The units are equipped with a
filter monitor as standard. This is achieved with
pressure sensors that measure the resistance via a
filter to issue dirt notification.