A Comprehensive Guide to the Essential Parts of an Air Conditioning System

Figure 1: AC outdoor units.

Air conditioning systems are complex machines that require various parts to function properly. Understanding the different parts of an air conditioner can help you troubleshoot problems, perform maintenance, and make informed decisions when it comes to repairs and upgrades.

In this ultimate guide to the list of AC parts, we will introduce the essential components of an air conditioner and how they work.

1. Main Parts of AC Unit

The main parts of an AC unit include the following types:

◆ The main parts of the AC cooling system are: compressor, four-way valve, pressure switch, solenoid valve, throttling parts, filter, globe valve, one-way valve, oil separator, heat exchanger (including evaporator and condenser), liquid storage tank, vapor-liquid separator, etc.

◆ The main components of the AC electrical system are: main board, fan, thermostat, temperature sensor, water level switch, capacitor, transformer, contactor, relay, etc.

The following will introduce 12 air conditioner components.

1.1 Compressor

The compressor is the heart of the air conditioning system. It is responsible for compressing and circulating the refrigerant, which is the substance that absorbs heat from the air. The compressor is typically located in the outdoor unit of a split-system air conditioner.

Common air conditioner compressors include the following 5 types:
● Reciprocating (piston) Compressor
● Rolling Piston Compressor (Rotary Compressor)
● Scroll Compressor
● Screw Compressor
● Centrifugal Compressor

Figure 2: Mitsubishi AC compressor.

Reciprocating (Piston) Compressor
1-20 RT (Refrigeration Ton): For commercial buildings or domestic uses.
1-130 RT: Used in commercial buildings or industrial facilities.

Rolling Piston Compressor (Rotary Compressor)
It is generally used on air-conditioning units below 3 RT, and it is commonly used on household air-conditioning units.
Features: few parts, simple structure; no suction valve, small clearance volume; small size, light weight, stable operation.
Disadvantages: Poor sealing performance and large vibration.

Scroll Compressor
Power per unit 3HP~25HP, mainly used in central air conditioners (household and commercial).
Features: a. High efficiency, energy saving; b. Soft start, low noise; c. Small size and light weight;
d. Stable operation, small gas pulsation, small torque change, long life; e. Strong ability to resist liquid slugging.

Screw Compressor
Power per unit 40HP~400HP, mainly used for commercial central air conditioners and other larger equipment.
Features: a. Simple structure, less wearing parts; b. Low gas discharge temperature under large pressure difference; c. Good gas transmission regulation performance;
Disadvantages: bulky, heavy, and relatively expensive.

Centrifugal Compressor
The single unit capacity is above 100RT, mainly used for commercial central air conditioners and other large equipment and building complexes.

1.2 Condenser

The condenser is another important part of the air conditioning system. It is located in the outdoor unit and works with the compressor to circulate the refrigerant. The condenser is responsible for releasing the heat that is absorbed by the refrigerant as it circulates through the system.

1.3 Evaporator Coil

The evaporator coil is located in the indoor unit of a split-system air conditioner. It is responsible for absorbing heat from the air as it passes over the coil. The refrigerant in the coil evaporates, which cools the air and removes excess moisture.

Figure 3: Evaporator coil.

1.4 Throttling Device

The expansion valve is located between the evaporator and condenser coils and is responsible for regulating the flow of refrigerant through the system. It controls the amount of refrigerant that is released into the evaporator coil, which affects the cooling capacity of the system.

Figure 4: Expansion valves.

1.5 Refrigerant Lines

The refrigerant lines connect the indoor and outdoor units of a split-system air conditioner. They transport the refrigerant between the units, allowing it to absorb and release heat as it circulates through the system.

1.6 Air Filter

The air filter is an essential part of the air conditioning system. It is located in the indoor unit and is responsible for trapping dust, dirt, and other contaminants as the air passes through the system. A dirty or clogged air filter can reduce the efficiency of the system and lead to poor indoor air quality.

1.7 Blower Motor

The blower motor is located in the indoor unit and is responsible for moving the air through the system. It works in conjunction with the evaporator coil to cool and dehumidify the air.

1.8 Thermostat

The thermostat is the control center of the air conditioning system. It is responsible for monitoring the temperature and humidity levels in the indoor space and communicating with the air conditioner to maintain the desired temperature.

Figure 5: Air conditioner thermostat.

1.9 Fan

The fan is located in the outdoor unit and works in conjunction with the condenser to release heat from the refrigerant. It is responsible for circulating air over the condenser coil, which allows the refrigerant to release heat into the outdoor air.

1.10 Capacitor

The capacitor is a small electrical component that provides the energy needed to start the compressor and blower motor. It stores electrical energy and releases it when needed to provide a boost of power to these components.

Figure 6: Capacitors for air conditioners.

1.11 Contactor

The contactor is an electrical switch that controls the power supply to the compressor and fan. It is responsible for turning the components on and off as needed to maintain the desired temperature in the indoor space.

1.12 Ductwork

The ductwork is the network of pipes and channels that distribute the cooled air throughout the indoor space. It is important to ensure that the ductwork is clean and free of leaks to maximize the efficiency of the air conditioning system.

2. Conclusion

Understanding the different parts of an air conditioning system is essential for maintaining and repairing the system. If you are experiencing issues with your air conditioning system, it's important to work with a licensed HVAC professional to diagnose and repair the problem. By working with a professional, you can ensure that your air conditioning system is functioning properly and efficiently.

3. FAQs

3.1 What is the Outside Part of an AC Unit Called?

The outside part of an AC unit is called the “outdoor unit", "condenser unit" or "condensing unit". It typically contains the compressor, condenser coil, and a fan, and is responsible for releasing the heat that is removed from inside your home or building by the indoor unit.

3.2 What Parts Does the AC Outdoor Unit Include?

The parts of AC outdoor unit typically includes the following parts:

Compressor: This is the heart of the AC system, responsible for compressing and circulating the refrigerant.

Condenser coil: This is a network of tubes that allow the refrigerant to release heat to the outside air.

Fan: This blows air over the condenser coil to help dissipate the heat.

Refrigerant lines: These are copper tubes that connect the indoor and outdoor units and allow the refrigerant to flow between them.

Capacitor: This is an electrical component that helps start the compressor and fan motors.

Contactor: This is an electrical switch that turns the compressor and fan motors on and off.

Control board: This is the electronic brain of the AC system, responsible for controlling the various components and functions of the unit.

Housing: This is the outer casing that encloses and protects the components of the condenser unit from the elements.

Figure 7: AC indoor unit.

3.3 What Parts Does the AC Indoor Unit Include

The AC indoor unit, also known as the air handler or evaporator unit, typically includes the following parts:

Evaporator coil: This is a network of tubes that allows the refrigerant to absorb heat from the indoor air.

Blower: This circulates the indoor air over the evaporator coil and distributes the cooled air throughout the home or building.

Air filter: This removes dust, dirt, and other airborne particles from the indoor air.

Drain pan: This collects condensation that forms on the evaporator coil and directs it to a drain line.

Drain line: This carries the condensation from the drain pan to the outside of the home or building.

Expansion valve: This regulates the flow of refrigerant into the evaporator coil.

Control board: This is the electronic brain of the AC system, responsible for controlling the various components and functions of the unit.

Housing: This is the outer casing that encloses and protects the components of the air handler from the elements.

It's worth noting that the specific components of an AC indoor unit can vary depending on the type and model of the system.

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