AC's and coolers are based on Newton’s law of cooling.
What happens when we place hot water in
a bowl?
Initially the temperatures falls rapidly
and then slowly. This is because of Newton’s law of Cooling. When the
difference in temperature between the hot water and the environment is high,
the exchange of heat between the environment and the hot water is fast. Its
like the tendency of the hot water to co-operate with the environment. It also
desires to come to the same state of the environment.
In Air conditioner, the heat inside the
room in the form of hot air ( high temperature), is absorbed by a coolant ( low
temperature ) and is exhausted to the outside atmosphere. Exchange of heat
occurs between the room and the coolant. The coolant (liquid) changes its form
to gas by absorbing heat and was expelled towards outlet. There it releases
heat and becomes liquid again, which is again used for absorbing heat from the
room. This takes place as a continuous process.
Coolant absorbs heat and evaporation
occurs (Evaporator part in AC)
The hot gas expands and cools to liquid
again due to exchange of heat from outside air (Condenser)
To use the same coolant again and again
for air conditioning purpose , compressor is used in the system.
What is the difference in working
between air conditioner and air cooler?
Instead of coolant, in air cooler, water
is used. Have you heard that we have to replace water in air cooler often.
There will be moist pads inside the cooler and simple air movement system is
enough. Because of air rotation, hot air is absorbed by the cold air in the
cooler, hot air is condensed by the moist pads and again flown as cool air in
to the room.
