Chiller Working
Principle
Parts of Chiller
Condenser
Compressor
 Expansion Valve
Evaporator
Working Principle of Chiller
Step-1-2 of Chiller Cycle
 Refrigeration cycle starts with a lowpressure liquid/gas mix entering the
evaporator. In the evaporator, heat from
the process water boils the refrigerant,
which changes it from a low-pressure
liquid to a low-pressure gas.
 Refrigerant gets vaporized by taking heat
from chilled water in evaporator.
 Refrigerant comes out of evaporator as
vapors but on other side chilled water is
produced.
 Thus heat is added to refrigerant at
constant pressure but is extracted from
chilled water.
Step-2-3 of Chiller Cycle
 Refrigerant vapors come
out of evaporator and then
compressed by chiller
compressor to high
pressure and temperature.
 Compressor requires energy
input for its working and
hence electric energy is
supplied to it.
Step-3-4 of Chiller Cycle
 High-pressure gas enters the condenser
where ambient air or condenser water
removes heat to cool it to a highpressure liquid.
 Refrigerant rejects its heat to outside
cooling liquid or air.
 Refrigerant gets condensed and outside
media is heated. outside media e.g.
cooling water may be cooled by cooling
tower and recycled again into condenser.
Step-4-1 of Chiller Cycle
 High-pressure liquid travels to the
expansion valve, which controls how
much liquid refrigerant enters the
evaporator, thereby beginning the
refrigeration cycle again.
 Refrigerant in condensed form coming
out of condenser is expanded in
expansion valve and its pressure and
temperature is reduced to level of
evaporator so that above cycle is
repeated again.
Types of Chillers:
 Water cooled & Air cooled.
 Water-cooled chillers feature a water-cooled condenser connected with
a cooling tower.
 Water-cooled chillers are basically used for medium and large
installations that have a sufficient water supply.
 Water-cooled chillers can produce more constant performance for
commercial and industrial air conditioning because of the relative
independence to fluctuations of the ambient temperature.
 Water-cooled chillers range in size from small 20-ton capacity models to
several thousand-ton models that cool the world’s largest facilities such
as airports, shopping malls and other facilities.