Compressor, Condenser and Outer Cover are parts of Air Conditioners.

2. The Basic Principle
 It works on the principle of successive heating and
cooling of a volatile liquid, Freon.
 This makes the environment successively cooler.
 It absorbs the heat from the environment and cools the
air.

3. Compressor
 Compressor is the single most expensive part inside an
AC unit.
 The liquid first enters the compressor and is converted
into a gas.
 This releases heat and makes the liquid cooler.

4. Condenser
 The cooled gas from the compressor enters the
condenser.
 The gas then absorbs the heat from the surrounding
and turns into a liquid again.
 The whole cycle continues cooling the room.

5. Outer Cover
 There is nothing much that the outer cover does other
than provide an esthetic appeal.
 It is generally made of molded plastic of different
shapes, designs and colors.