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TurboChill™ Chillers
12 TurboChill Water Cooled Technical Manual 9216326 V1.13.0 07_2018
Electronic Expansion Valves (EEV)
Electronic expansion valves differ to the normal thermostatic expansion valves in their ability to maintain control of
the suction superheat at reduced head pressures. This can lead to significant energy savings particularly at reduced
loading and low ambient temperatures. EEV step position, superheat setpoint, head pressure set point and other
features can be viewed and adjusted via the microprocessor display.
Whilst offering versatile control at the full design duty of the unit, Thermostatic Expansion Valves (TEV) do not
automatically optimise themselves to all operating conditions. Therefore, if the refrigeration system is operating at 40%
or 50% of full load, especially at a lower ambient temperature than that for which the valve was sized, the conventional
TEV must have the design head pressure available to ensure good refrigerant control. Maintaining an artificially high
condensing pressure is normal in conventional systems.
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.
EEVs differ from thermostatic expansion valves in their ability to maintain control of refrigerant flow and suction
superheat at reduced head pressures. The turn-down rate of a typical EEV is superior to that of it’s thermostatic
equivalent, such that a reduced optimum condensing pressure can be maintained at low compressor load.
An EEV can operate effectively between 10-100% of its rated capacity.
Sight Glass
A liquid line sight glass is fitted to give an indication of the state of the refrigerant within the system. If the sight glass
becomes yellow it is an indication that there is moisture in the system and the filter drier may need changing.
Liquid Line Ball Valves
Liquid line ball valves are fitted to ensure ease of maintenance during shut down periods.
Discharge Line Ball Valves
Discharge line ball valves are fitted to ensure ease of maintenance during shut down periods.
Filter Driers
Filter driers are fitted to ensure that the expansion device is protected from any potential contaminants and to absorb
any unwanted moisture in the system. This can be serviced with changeable inner cores.
HP/LP Transducers and Switches
HP/LP Transducers and switches are fitted to the unit to protect against high or low pressures. High pressure switches
are auto reset.
Leak Detection
A factory calibrated and fitted leak detection system shall raise an alarm when refrigerant gas is detected. The detector
will be positioned close to the compressor section.
A premium package is available that monitors refrigeration parameters and determines if loss of refrigerant is occurring.
This can detect which circuit is leaking from these parameters making an intelligent decision of potential shut-down of
the unit.
Introduction