Automotive Air Conditioning Systems
WHY AC SYSTEM?Stopped in traffic on a may afternoon?Sweat drips all over your body?Hands feel like they are about to slip away from
the steering wheel due to sweat?Need a luxurious and a comfortable ride?Why don’t you attach an automotive air
conditioning system to your ride, which 99% of all new cars produced since 2010 are equipped with?
HOW DOES IT WORK?Main function- to cool and remove humidity
from air inside the car.Parts of a typical car AC system are: (i)Compressor (ii)Condenser (iii)Receiver or
Dryer (iv)Expansion valve (v)Evaporator
COMPRESSOR
It is a pump driven by a belt attached to the engine’s crankshaft.
Puts the refrigerant gas under pressure and forces it to the condenser.
It cant compress liquids, only gases.By increasing the pressure the refrigerant gas leaving
the compressor becomes hot.Also called as heart of the air conditioning system. Earlier freons(R-12) were used as refrigerants.
Nowadays they are replaced by environment friendly HFC(R-134a).
CONDENSERIdentified as second radiator of the car that
shares air flow with main radiator.Has its own cooling fans that become active
when AC is on.Takes up the heat from the high pressure
refrigerant gas and cools it.Condensing of the refrigerant gas causes it to
loose heat and form into a liquid.Heat is expelled into the atmosphere by the air
flowing from the cooling fans.
RECEIVER OR DRYERSmall reservoir installed in the line of the
condenser.Main function is to remove moisture and other
contaminants from the cool refrigerant liquid.Contains small granules called desiccants that
attract water.If water is not removed, it can form ice crystals,
thereby damaging the whole system.
EXPANSION VALVEHere the pressure of refrigerant is reduced
causing expansion of the liquid, resulting in further cooling.
Slowly the liquid reverts back into a gaseous form.
Also the valve reduces pressure on the refrigerant so it can easily move into the evaporator.
The valve senses pressure and regulates the flow of refrigerant, which allows the system to operate steadily.
EVAPORATORRadiator like device buried deep under the
dashboard.Refrigerant gas enters the evaporator coils and
absorbs the heat inside the car’s cabin and moves out of the coils.
A fan blowing over the outside of the evaporator coil blows cool air into the passenger compartment.
Thus the evaporator takes humidity out of the air in the car, which helps you feel cool.
SCHEMATIC DIAGRAM FOR EASY UNDERSTANDING
CONCLUSION An AC system not only cools the cabin, it
removes dust and dirt, leaving only with fresh air.
One has to remember to use only environment friendly refrigerants and avoid CFCs as much as possible.
The AC system can be recharged by adding fresh refrigerant and removing the remaining one.
Care must be taken in the disposal of refrigerants as they may affect the soil, rivers, etc.,
Its also necessary to check the AC system for leaks as it may lead to the loss of refrigerant as well as environmental hazards.
Thank you…Anyways, let us minimize the usage of ACs and
go green!
