Airedale OptiChill FreeCool 500kW - 1365kW - Manual (Page 46)

OptiChill Freecool
Active Cabinet Exhaust
Chillers
46
Chillers
Technical Manual : 7197700 v1.2.0. 02_2013
Design Features & Information
Economiser ES The addition of an economiser circuit provides increased cooling and enhances EER,
in full and part load operation.
Sub-cooled liquid is expanded using a dedicated EEV to ‘ medium’ pressure and
passed through one side of a plate heat exchanger. Through the other side flows the
‘normal’ pressure liquid. The result is that the subcooling of the liquid entering the
system EEV is increased, which increases evaporator performance and
simultaneously the suction pressure within the compressor body is lifted, improving
compressor efficiency.
Electronically
Commutated (EC)
Fan Motor ES EC motors are DC motors with integrated AC to DC conversion; this gives the flexibility
of connecting to AC mains with the efficiency and simple speed control of a DC motor.
The EC fan offers significant power reduction in comparison with equivalent AC fan at
modulated fan speeds. The inbuilt EC fan control module allows for fan speed
modulation from 15-100%, a standard AC fans modulating range is typically 40-100%
of full fan speed.
The EC fan presents superior energy efficiency, at part load fan speeds compared to
the equivalent AC fan motor, offering typical efficiency savings up to 70%.
Standard voltage regulated (VR) fan speed controllers offer a linear response. By
comparison the EC fan is adjusted on demand via the unit microprocessor with
precision, offering substantial energy savings. The following illustration shows a
comparison of the typical power input required by each method.
In
pu
t Po
w
e
r %
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Key
EC (Electronically
Commutated) Fan
Speed Control
Voltage Regulated
(VR) Fan Speed
Control
Fan Speed %
Example: Fan speed of 60%
VR input power required 60%
EC input power required 18%