Airedale TurboChill FreeCool 200kW - 1830kW - Manual (Page 17)

17 Chiller Technical Manual 7525355 V1.1.0_04_2013
Introduction
Chillers TurboChill™ Air Cooled and FreeCool
Evaporator
Flooded evaporator incorporating an internal round tube heat
exchanger. This heat exchanger is used to further sub-cool
refrigerant leaving the condenser extending the potential cooling
capacity and as a result, efficiency of the system. At the same time
suction gas vapour that passes over the heat exchanger within the
shell is superheated to a higher temperature, eliminating the risk of
wet vapour returning to the compressor.
The heat exchanger is insulated with closed cell polyurethane
foam which is to Class O fire rating and the material is UV
resistant.
The flooded evaporator results in significant energy savings in
compressor operation particularly at part load.
Two immersion heater(s) and thermostat protect the evaporator
against freeze up in ambient temperatures down to -20°C. (in
compliance with Airedale freeze protection policy).
Connections for External Trace Heating (240V / 500W available).
Compressors and evaporator shall be mounted on a rigid
galvanised heavy duty sub frame. Fully weatherproofed electrical
panels are situated at one end of the unit.
Actuated Suction Ball Valve(s)
To protect the compressors against liquid migration, actuated
suction line ball valves shall be fitted. This protects the
compressors when their is no cooling demand by keeping the
refrigerant in the evaporator, even if water is still flowing through
the unit.
Economiser Circuit for Increased Part Load Efficiency
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 (electronic expansion valve) 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 sub cooling of the liquid entering the system EEV is increased, which improves evaporator
performance and at the same time the suction pressure within the compressor body is lifted, improving compressor
efficiency.