Subject:- Refrigeration and Air Conditioning

Topic:- Design of air conditioning systems

Difficulty:- Medium

The split air conditioning system comprises of two parts: the outdoor unit and the indoor unit. The outdoor unit fitted outside the room, houses components like compressor, condenser and expansion valve. The indoor unit comprises of the evaporator and the cooling fan.

The two sections are connected with a set of electrical wires and tubing used to transport air between the two sections. The compressor is controlled by a thermostat which on detecting warm air activates compressor outdoors. The compressor increases the pressure and temperature of refrigerant gas and passes it to condenser.

Heat is removed from the high pressure gas in condenser and the gas changes phase to liquid. This chilled liquid is pushed through tubing indoors and reaches the evaporator.

The evaporator fan collects warm air from inside the room and passes it through a chamber containing chilled liquid refrigerant.

The fan system also serves to blow this now-cooled air back into the room, lowering the overall temperature of the space.

The refrigerant is passed back outdoors to the compressor in order to repeat the cycle.

If the thermostat still detects air that is warmer than desirable, the process continues.

Advantages:

• Compact and very little chance for heat and other energy to escape the system

• No energy wastage because no ducts required

• Provides reliable cooling to large spaces or multiple rooms

• Easy to operate and maintain

• Low operating cost

Disadvantages:

• They do require some electrical wiring and other specialized installation techniques

• Relatively higher installation cost.