Airedale OptiChill FreeCool 500kW - 1365kW - Manual (Page 35)

Chillers OptiChill Freecool
Chillers
35
Technical Manual : 7197700 v1.2.0 02_2013
General Description
Standard Features
Construction The base is fabricated from galvanised steel to ensure a rigid, durable and
weatherproof construction.
Unit panels are manufactured from galvanised sheet steel coated with epoxy baked
powder paint to provide a durable and weatherproof finish.
Standard unit colour is Light Grey (RAL 7035).
The compressors and evaporator are mounted on a rigid galvanised heavy-duty sub
frame. Fully weatherproofed electrical panels are situated at one end of the unit.
Evaporator
Shell and tube heat exchangers constructed from a steel shell with internally enhanced
copper tubes. Internal baffles in the water circuit optimise flow whilst keeping pressure
drop to a minimum. The heat exchanger is insulated with closed cell polyurethane foam
which is to Class O fire rating and the material is UV resistant.
Water inlet and outlet connections are of grooved type pipe and coupling assembly,
optional flanged connections available on request, please consult Airedale.
An immersion heater and thermostat protect the evaporator against freeze up in ambient
temperatures down to -20°C.
Connections for External Trace Heating (230V/500W available).
Free Cooling Coil The OptiChill Free Cool chiller has been designed to provide the cooling load required
whilst optimising energy efficiency at all times and as such will take advantage of free
cooling whenever available. If the free cooling available cannot satisfy the required full
cooling load, direct expansion cooling is used to supplement the output.
The Free cool coil is manufactured from copper tube and aluminium fins.
Free Cooling Operation In high ambient where free cooling is not available the fan speed modulates in the
conventional manner to maintain an optimised head pressure. Free cooling is initiated
wherever the outdoor ambient is 1°C less than the return water temperature.
In ambient temperatures where the free cooling coil is capable of satisfying the full
cooling demand, the condenser fans are modulated to provide the desired duty. The
condenser fans are capable of being modulated between 25-100% of maximum airflow
to maintain the supply water temperature.
During periods where the condenser fan speed has been reduced to a minimum, the
supply water temperature will then be controlled by the 3 way valve.
Water Connections Water inlet and outlet connections are of a grooved and clamped type construction. The
unit is supplied with a counter pipe and coupling assembly for a butt welding connection.
Evaporator Differential
Pressure Sensor Facilitates low flow limiting and pressure drop monitoring via the microprocessor.
(Additional flow protection is required. See optional features)
Condenser
Large surface area coils ideally positioned to optimise airflow and heat transfer,
manufactured from refrigeration quality copper tubes with mechanically bonded
aluminium fins.
The copper tube is internally rifled for improved heat transfer.