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OMEGA SKY XI
Omega Sky Xi is a water-condensed liquid chiller for in
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door applications, available in heat pump version also.
This range features a semi-hermetic, inverter-controlled
screw compressor to obtain max. performances at partial
loads, a latest generation Hybrid Falling Film evaporator
with low refrigerant load, and a flooded shell and tube
condenser.
These elements make Omega Sky Xi an extremely per
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forming machine in all operating conditions, which enables
it to largely exceed the targets mandated by the existing
regulations and to ensure max. comfort levels.
REFRIGERANT
Refrigerant R513A standard.
R513A is distinguished by its low environmental impact,
with GWP=573 (*). It is also a non-toxic and non-flam
-
mable fluid: A1 classification in accordance with ASHRAE;
PED 2.
These characteristics make R513A ideal for indoor units;
they also facilitate adoption of the model in places where
there are certain local requirements regarding the envi
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ronmental impact caused by refrigerants.
This has positive effects on transport, operation and main
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tenance and also on overall cost effectiveness, as regards
possible taxation or restrictions on the use of refrigerants
with high environmental impact.
The model can be supplied with refrigerant R134a as op
-
tion.
(*) GWP (AR5), pursuant to IPCC V, evaluated over a span
of 100 years.
STRUCTURE
Consists of polyester powder coated hot dip galvanised
sheet steel profiles (RAL 9005).
The electrical control panel is made in a polyester pow
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der-coated hot dip galvanised sheet steel box (RAL 7035).
COMPRESSORS
Units fit innovative screw compressors with a variable
compression ratio, which ensure optimised operation un-
der all operating conditions.
The BlueThink controller constantly monitors the evaporat
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ing and condensing temperatures of the unit and changes
the compression ratio of the compressors to obtain the
max. achievable efficiency.
The compressors in use are designed according to an ex
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clusive BlueBox specification in order to achieve max. effi
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ciency both under partial and full load conditions.
Continuous reduction of the output capacity is implement-
ed with a regulation from 25% to 100% in order to achieve
the highest energy efficiency levels on the market, with
special reference to cooling applications. The variation of
the compression ratio caused by the sliding of the internal
slide valve, in combination with capacity reduction of the
refrigeration demand by the inverter, allows for the maxi
-
misation of the energy efficiency of the unit in all operat
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ing conditions.
In addition to managing capacity modulation, BlueThink
also controls all safety devices so that the compressor can
operate within its operating limits at all times and simulta
-
neously safeguard its operation and reliability. Compressor
lubrication is ensured by the pressure difference between
the delivery and the suction lines, thanks to the regulation
action performed by BlueThink.
All the compressors are fitted with check valve on delivery
side, metal mesh filter on suction side and electronic pro
-
tection with temperature sensors directly inserted in the
windings and on the delivery pipe.
Startup in compressors featuring an inverter is of the “Di
-
rect On Line” type with an inverter-controlled acceleration
ramp that minimises inrush currents.
In addition to the obvious energy savings arising from
greater efficiency, the use of a full inverter unit also brings
advantages in terms of installation:
•
For these units, the cosφ (power factor) is always great
-
er than 0.95, therefore making external power factor
correction systems unnecessary.
•
The maximum inrush current of the unit is always lower
than its maximum absorbed current (calculated in the
worst operating condition), therefore making the power
cables and line protection devices less onerous.
All the compressors are fitted as standard with crankcase
heater and discharge valve.
SOURCE-SIDE HEAT EXCHANGER
Flooded shell-and-tube heat exchanger, with single water
passage on tube side. Steel shell, and tube bundle made
with copper tubes. The heads can be removed for tube
inspection and cleaning. Victaulic couplings on water side
(complete with nipple for connection).
USER-SIDE HEAT EXCHANGER
Latest generation shell and tube heat exchanger Hybrid
Falling Film with two passes.
The new technology combines the features of a traditional
flooded evaporator and the Falling Film evaporator, thus
ensuring low approach temperatures and a low refrigerant
load.
Below is a sample cross-section of the evaporator.
