Airedale StoreMaster 50kW - 77kW - Manual (Page 18)

STOREMASTER
™
Comfort
18
Comfort Range
Technical Manual : 6678403 V1.3.0_ 02_2013
Design Features & Information
ENERGY SAVING FEATURES
Electronic Expansion
Valves (EEV) Using an EEV allows for good refrigeration control whilst operating at part load
and lower ambient conditions with a reduced condensing pressure. By fitting an
EEV and adjusting the head pressure control setting an increase in the system
EER (Energy Efficiency Ratio) of up to 30% can typically be seen. The
Mollier diagram shown below helps to illustrate how this increase in efficiency
is achieved.
EEV’s differ to normal thermostatic expansion valves in their ability to maintain
control of refrigerant flow and the suction superheat at reduced head pressures.
The turn-down rate of a typical EEV is superior to that of its thermostatic
equivalent, such that a reduced optimum condensing pressure can be
maintained at low compressor load. However low the load is on the compressor,
from zero to 100%, there will not be a problem with turn down, even down to
10% of the valve’s rated capacity.
1
2
3
4
A B
Bubble Dew
1
2
3
4
A B
TEV
EEV
1
Compression
2 Condensation
3 Expansion
4 Evaporation
Reduced Condensing
Pressure
Pres
s
ure
(ba
ra)
Evaporating Pressure
1
2
3
4
A B
X
Y
Enthalpy
(kJ/kg)
1
2
3
4
A B
X
Y
Increase in
Cooling Duty
Reduction in
Input Power
Key: Cooling Cycle @ 22°C ambient with a conventional TEV fitted.
Cooling cycle @ 22°C ambient, demonstrating a typical EEV condensing temperature taking full advantage
of lower ambient air temperatures (below 30°C).
Electronically
Commutated (EC) Fan
Motor Option 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 both full and modulated fan speeds. The inbuilt EC fan
control module allows for fan speed modulation from 20-100%, a standard AC
fans modulating range is typically 40-100% of full fan speed.
The EC fan offers superior energy efficiency at full and reduced fan speed
compared to the equivalent ac fan motor.