Construction of Split Air Conditioner (Wall / Floor / Cassette)

In the Refrigeration and Air Conditioning (RAC) trade, understanding the construction of split air conditioners is essential for installation, servicing, and troubleshooting. Split air conditioning systems are widely used due to their efficiency, quiet operation, and flexible installation. This chapter explains the constructional details of wall-mounted, floor-mounted, and cassette-type split air conditioners.

Basic Construction of Split AC

A split air conditioner consists of two main units:

• Indoor Unit
• Outdoor Unit

These units are connected by refrigerant pipes, electrical wiring, and a condensate drain line. The separation of components reduces indoor noise and improves system efficiency.

Construction of Indoor Unit

The indoor unit is installed inside the room and is responsible for cooling and air circulation. Its main components include:

• Evaporator Coil: Made of copper tubes with aluminum fins, it absorbs heat from indoor air.
• Blower Fan: Circulates air over the evaporator coil and distributes cooled air into the room.
• Air Filter: Removes dust and impurities from incoming air.
• Drain Tray and Pipe: Collects and drains condensate water formed during cooling.
• Control Panel: Contains electronic controls, sensors, and display system.

The indoor unit is enclosed in a plastic or metal casing designed for aesthetics and efficient airflow.

Construction of Outdoor Unit

The outdoor unit is installed outside the building and is responsible for heat rejection. Its main components include:

• Compressor: The heart of the system, it compresses refrigerant to high pressure and temperature.
• Condenser Coil: Releases heat from refrigerant to the outside air.
• Condenser Fan: Draws air over the condenser coil to enhance heat transfer.
• Expansion Device: Usually located near the indoor unit (capillary or expansion valve).
• Protective Casing: Metal enclosure to protect components from weather conditions.

Refrigerant Piping and Connections

The indoor and outdoor units are connected by copper pipes:

• Suction Line: Carries low-pressure refrigerant vapor to the compressor
• Liquid Line: Carries high-pressure liquid refrigerant to the evaporator

Proper insulation of pipes is necessary to prevent heat loss and condensation.

Construction of Wall-Mounted Split AC

Wall-mounted split AC is the most common type. The indoor unit is fixed on the wall at a height, ensuring proper air distribution.

• Compact indoor unit with horizontal airflow
• Lightweight and easy to install
• Suitable for small rooms and offices

The outdoor unit is placed outside the wall or on a bracket.

Construction of Floor-Mounted Split AC

Floor-mounted units are installed at a lower level, near the floor or wall base. Their construction is similar to wall-mounted units but designed for vertical airflow.

• Larger indoor unit placed near floor level
• Strong airflow at lower height
• Suitable for halls and large rooms

Construction of Cassette Type Split AC

Cassette air conditioners are installed in false ceilings. Only the front panel is visible inside the room.

• Evaporator unit hidden above ceiling
• Four-way air distribution system
• Drain pump for condensate removal

The outdoor unit remains similar to other split AC systems.

Electrical and Control System

Split AC systems include advanced control systems:

• Thermostat and temperature sensors
• Remote control operation
• Printed circuit board (PCB)
• Protection devices such as overload protectors

These components ensure safe and efficient operation.

Airflow Design

Proper airflow is an important aspect of construction:

• Indoor unit ensures uniform air distribution
• Outdoor unit ensures effective heat rejection
• Air filters maintain air quality

Advantages of Split AC Construction

• Reduced indoor noise
• Flexible installation options
• Efficient cooling performance
• Modern and aesthetic design

Conclusion

The construction of split air conditioners involves careful design of indoor and outdoor units, refrigerant piping, and control systems. Each type—wall-mounted, floor-mounted, and cassette—has unique construction features suited to different applications.

Understanding these construction details helps RAC technicians in proper installation, maintenance, and troubleshooting. With modern advancements, split AC systems continue to evolve, offering better efficiency and comfort.