Category: Technical information associated with Flakt Woods Energy
Saving Technology
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Fläkt Woods Energy Saving
Technology
Twin Wheel Energy Saving Technology System
The Fläkt Woods Twin Wheels and Controls package is helping
specifiers gain significant energy savings from air handling units
providing fresh air to active chilled beams.
In any application with a high density of occupation within rooms,
dew-point temperature control can now be achieved using the Fläkt Woods
Wheels and Controls package to maintain room conditions. This has the
dual effect of reducing the cooling load on the cooling coil and
eliminating the requirement for reheat on the heater battery during the
summer cycle, thus contributing to significant energy savings.
How it works
This system uses both a hygroscopic thermal wheel and a
non-hygroscopic thermal wheel with a cooling coil in between. The
non-hygroscopic wheel reheats the air from the cooling coil, eliminating
the need for a reheater. At the same time, it cools the extract air.
This cooled extract air goes onto the hygroscopic wheel and this
provides enough cooling recovery to reduce a typical cooling load by
half.
The package does not require a regeneration heater or adiabatic
humidifiers.
Conclusions
Calculations show considerable energy savings over systems without
any form of heat recovery. In practice, with today’s emphasis on energy
recovery, most systems will include some method of heat recovery.
Nevertheless, this system shows a marked efficiency improvement in the
summer cycle and is better in the winter cycle than most systems with
some form of heat recovery.
The Fläkt Woods Wheels & Controls package should also be considered for
applications such as:
Chilled Beam Systems – the system dehumidifies the fresh air so that
there is no risk of ‘rain’ in the zones served by three chilled beams.
The system halves the fresh air cooling load and eliminates the need for
a reheater.
Fan Coil Systems – the dehumidification of the fresh air to the fan
coils will result in reduced moisture drop-out on the fan coils,
reducing energy costs.
Displacement Ventilation Systems – full fresh air systems without
humidifiers reduce the maintenance liability usually associated with
humidifier systems, with energy savings.

Fig 1: Air Handling Unit
Operation: The operation of the system is as follows : (refer to fig. 1)
Summer
E-G Outdoor air is initially cooled by the Fläkt Woods Wheels &
Controls package.
G-H It is further cooled and dehumidified, using the cooling coil, to
the required dew-point temperature.
H-C The supply air is then reheated to the required supply condition
using the Fläkt Woods Wheels & Controls
package, which extracts heat from the return air.
Winter
E-F Outdoor air heated by frost coil to 2ºC. (Only if required).
F-G Outdoor air heated and humidified by the Fläkt Woods Wheels &
Controls package.
G-C Supply air further heated by the Fläkt Woods Wheels & Controls
package.
C-J Heated to design condition by the heater battery.
For further information contact: craig.macfadyen@flaktwoods.com
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