The cooling coil is a copper coil made of number turns of the copper tubing with oneor more rows depending on the capacity of the air conditioning system. The cooling coil is covered with the aluminum fins so that the maximum amount of heat can be transferred from the coil to the air inside the room.
The refrigerant from the tubing at very low temperature and very low pressure enters the cooling coil.
The blower absorbs the hot room air and in doing so the air passes over the cooling coil which leads to the cooling of the air.
This air is then blown to the room where the cooling effect has to be produced.
The air, after producing the cooling effect is again sucked by the blower and the process of cooling the room continues.
After absorbing the heat from the room air, the temperature of the refrigerant inside the cooling coil becomes high and it flows back through the return copper tubing to the compressor inside the outdoor unit.
The refrigerant tubing supplying the refrigerant from the outdoor unit to the indoor unit and that supplying the refrigerant from indoor unit to the outdoor unit are both covered with the insulation tape.
Air Filter:
The air filter is very important part of the indoor unit.
It removes all the dirt particles from the room air and helps in supplying clean air to the room.
The air filter in the wall mounted type of the indoor unit is placed just before the cooling coil.
When the blower sucks the hot room air, it is first passed through the air filter and then though the cooling coil.
Thus the clean air at low temperature is supplied into the room by the blower.
Cooling Fan or Blower:
Inside the indoor unit there is also a long blower that sucks the room air or the atmospheric air.
It is an induced type of blower and while it sucks the room air it is passed over the cooling coil and the filter due to which the temperature of the air reduces and all the dirt from it is removed.
The blower sucks the hot and unclean air from the room and supplies cool and clean air back.
The shaft of the blower rotates inside the bushes and is connected to a small multiple speed motor, thus the speed of the blower can be changed.
When the fan speed is changed with the remote it is the speed of the blower that changes.
Drain Pipe:
Due to the low temperature refrigerant inside the cooling coil, its temperature is very low, usually much below the dew point temperature of the room air.
When the room air is passed over the cooling due the suction force of the blower, the temperature of the air becomes very low and reaches levels below its dew point temperature.
Due to this the water vapor present in the air gets condensed and dew or water drops are formed on the surface of the cooling coil.
These water drops fall off the cooling coil and are collected in a small space inside the indoor unit.
To remove the water from this space the drain pipe is connected from this space extending to the some external place outside the room where water can be disposed off.
Thus the drain pipe helps removing dew water collected inside the indoor unit.
To remove the water efficiently the indoor unit has to be a tilted by a very small angle of about 2 to 3 degrees so that the water can be collected in the space easily and drained out.
If this angle is in opposite direction, all the water will get drained inside the room. Also, if the tilt angle is too high, the indoor unit will shabby inside the room.
Louvers or Fins:
The cool air supplied by the blower is passed into the room through louvers.
The louvers help changing the angle or direction in which the air needs to be supplied into the room as per the requirements.
With louvers one easily changes the direction in which the maximum amount of the cooled air has to be passed.
There are two types of louvers: horizontal and vertical.
The horizontal louvers are connected to a small motor and their position can set by the remote control.
The vertical louvers are operated manually and one can easily change their position as per the requirements.
The horizontal louvers control flow of air in upper and downward directions of the room, while vertical louvers control movement of air in left and right directions.
has to be produced. 
below the dew point temperature of the room air. 
the requirements. 
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