Airedale BluCube 10-48kW - Manual (Page 9)

Condensing Units BluCube
™
Condensing Units
9
Technical Manual : 7206188 V1.6.0_07_2014
Hydrophilic Epoxy Coated Coil Fins shall be coated with a non-stick acrylic (hydrophilic) film to provide additional
corrosion protection and efficient surface water removal for improved performance.
Plain aluminium shall not be acceptable.
Fixed Capacity Compressor Can operate up to pressures of 40Bar. The compressor is fitted with a crankcase
heater which ensures reliable operation particularly during low ambient start-up. The
compressor is also fitted with a high and low pressure switch which ensures that the
compressor only operates within the acceptable envelope reducing the chance of a
compressor failure.
Variable Capacity Digital
Scroll Compressor Digital scroll compressor technology offers compressor capacity modulation from 16%
to 100%. Achieved by the use of an externally, integrated, long life electronically
controlled solenoid valve which loads and unloads the compressor scroll based on a
12 second cycle.
The solenoid valve uses suction and discharge pressures through a modulation
chamber to cause a spring loaded piston attached to the top scroll to fall down at high
pressure and move up at low. The moving of the piston separates the scrolls and
results in no compression of refrigerant.
As the digital compressor is always operating at either 100% or 0% the mass flow of
refrigerant through the system is always high, simplifying component selection and
pipe work design to guarantee oil return.
Energy Efficiency The digitally modulated solenoid achieves capacity modulation of 16% to 100% by
varying the loaded or unloaded compressor cycle time and averaging the sum of the
loaded and unloaded state. The digital scroll compressor operates in an unloaded
state for a proportion of the 12 second cycle time; as a result, the load on the
compressor is greatly reduced as refrigerant is not drawn. Consequently the energy
consumed at partial load condition is only a percentage of that consumed during full
load condition, ie:
(Loaded Time x 100%) + (Unloaded Time x 16%)
= Averaged Power
(Loaded Time + Unloaded Time)
Operation The following examples illustrate the flexibility of the digital compressor loading stages
within the 12 second cycle time:
Example A Where: Solenoid Energised = 6 seconds Loaded Time
Solenoid De-energised = 6 seconds Unloaded Time
(6 x 100%) + (6 x 16%)
= 58%
12
6 Secs 6 Secs 100% Capacity
0% Capacity
6 Secs 6 Secs
12 Secs
Example B Where: Solenoid Energised = 3 seconds Loaded Time
Solenoid De-energised = 9 seconds Unloaded Time
(3 x 100%) + (9 x 16%)
= 37%
12
3 Secs 3 Secs
9 Secs 9 Secs
12 Secs
Control & Monitoring The systems superheat is controlled by a dedicated microprocessor and digital
compressor performance is monitored via the AireTronix controller display.
CAUTION The digital scroll compressor is always operating at either 100% or 0% mass flow.
When inspecting the refrigerant system with gauges, this is evident by pulsing of
the system pressures. Therefore, all pressure measurements MUST be taken when
the digital scroll compressor is compressing refrigerant (solenoid de-energised).