Technical Description Multi-DENCO
32 FläktGroup DC-2013-0101-GB • Subject to modifications • R5-08/2020
3.6.1 Condensers
A-Version units typically use condensers to reject the heat that the Multi-DENCO unit
has absorbed from the room. They consist of a large coil and a fan to condense the
R410A gas into a liquid form. Condensers can be supplied with AC or EC fans and can
be installed with vertical or horizontal airflow.
Condensers can be installed either with a direct 1 to 1 relationship with the indoor unit
or 2 condensers can be used with a single Multi-DENCO unit as part of 1 single circuit.
This arrangement is refer to as 'twin condensers'.
Condensers can be fitted with winter kits to enable operation in low ambient tempera-
ture conditions. These winter kits use liquid receivers and expansion valves to enable
consistent operation of the refrigerant circuit by changing the volume of the condenser
coil available for heat rejection, based on the ambient temperature. As a result, this
requires extra commissioning actions that are detailed in chapter 8.3.11.
3.6.2 Chillers
C-Version units are typically used with chillers (usually several are connected to the
same chiller). The water inlet temperature and the room set point can determine the
capacity of the unit when using chilled water from a chiller.
Chillers are good for large scale and diverse cooling
‒ different operations can use the
same chiller for heat rejection, which could reduce plant space and costs. We are able
to offer freecooling chillers that can use low ambient temperatures to minimise energy
usage.
Separate operating manuals are supplied.
3.6.3 Condensing units
Condensing units perform the same functions as condensers, but they also contain the
compressor. Used for the X-Version of Multi-DENCO and H-Version of DENCO-Office-
Cool, usually the indoor unit would be used with 1 condensing unit, but for certain unit
sizes, 2 condensing units can be used. 2 circuits are used and the indoor unit has a
'split coil', half the coil operates with 1 condensing unit, the other half of the coil with
the other condensing unit.
Separate operating manuals are supplied with the outdoor units for this configuration.
3.6.4 Dry coolers
The drycoolers are similar to condensers, however they used water, rather than refrig-
erant, within their coils. They can be mounted in horizontal or vertical orientation also.
When used with FreeCool systems where lower ambient temperatures can be
expected, consideration must be made for the water / glycol concentration levels and
if any further installation measures must be taken to prevent pipework or coil from
freezing (e.g. insulation, trace heating etc.).
3.6.5 Hybrid Heat Rejection (DMOUHM)
This unit is a combination of a condenser (DMOUCD) and a drycooler (DMOUDW).
There are two coils, one for each circuit in the unit and they share a common set of EC
fans. The fan speed regulation is dependent upon which circuit (FreeCool or direct
expansion) is operating. If both circuits are operating, then direct expansion has the pri-
ority based on condensing temperatures and pressures.
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