How Compressor Works In AC And Refrigerator?

The compressors are source of compressed air and they are used in variety of electronic appliances. They are used in industries, automotive, inflating items such as kids' toys, and nail guns.

The compressors with several new and innovative features are evolving such thermal protection features and oil-free compressors. The refrigerator and Air Conditioners are among those appliances that use compressor technology.

We have already covered topics of compressors related to inflating car tires and bike tires but here we are going to discuss how do compressors work in air conditioner and refrigerator?

  Working of An AC compressor:

Air conditioners help to maintain the room temperature at the optimum level. They also help to eliminate the airborne particles and humidity from the room.

In order to understand the role of the compressor in AC let's understand the working principle of an AC.

Air Conditioner Working Principle:

The air conditioners have two connected coils which continuously flow refrigerants. The coil inside the room is called an evaporator and the coil inside the room is called a condenser.

The principle of an air conditioner is simple. Just keeping the evaporator coil and the condenser hot. 

In this way, the continuously surrounding fluid absorbs heat from the room and eject it out to the surrounding.

To achieve this objective, there is a need for two more components called the compressor and expansion valve. The compressor increases the pressure of a refrigerant. Usually, the compressor used in AC is a reciprocating type compressor.

The compressor handles the refrigerant in a gaseous state. It compresses the gas and the temperature rises along with the pressure. The temperature of the compressor outlet will be far higher than the atmospheric temperature.

Therefore, when you pass this hot gas through the condenser heat exchanger the heat can be ejected easily. A fan on the condenser makes this task easier. During this heat ejection phase, the gas condenses to a liquid. An expansion valve is fitted at the exit of the condenser. It restricts the refrigerant flow and makes the refrigerant cold.

  Problem with the AC compressor:

i). Temperature and mass flow:

To control the rate of mass flow and the temperature is a critical aspect for the satisfactory performance of the compressor. The mass flow is the amount of the gas coming down the suction line. In order to prevent overheating gas flow must be controlled.

ii). Compression ratio:

The heating of compressor depends upon compressor ratio. It is is the absolute discharge pressure divided by the absolute suction. Basically, it means when the compressor has to do more work it has to increase the pressure from lower to higher. Where the difference between lower and higher pressure is larger those compressors will get heat up quickly.

iii). Oil loss:

The small amount of oil is circulated with in the refrigerant for lubrication of the compressor components. But the liquid refrigerant can cause the foaming and loss of oil. Also, the overheating can result in break down of oil.

  Working of the Refrigerator compressor:

In order to consider the role of compressor in the working of AC you will have to understand how refrigerant circulates with in the refrigerator system. The basic function of a compressor is air compression. The refrigerant moves to all the components of the refrigerator like evaporator, compressor, and, condenser.

It reaches the compressor from evaporator. The refrigerant coming out of the evaporator is very cool so the compressor compresses it and makes it a hot and high-pressure gas. This hot gas travels through the coil and exchanges heat with the surrounding. As it releases heat it again becomes cold and is converted into liquid state.

Further, it moves to the expansion valve and there it becomes partial liquid and partial gas. This liquid gas flow through coils absorbs heat inside the refrigerator and provides cooling.

  Problems with The Refrigerator compressor:

i). Fan problem:

A fan is the most important component for a compressor because it protects the compressor from overheating. The process of compression produces sufficient heat making the unit sufficiently hot. Most of the time, the disorder of a compressor is related to the malfunction of its fan.

ii). Overload problem:

If you face the tripping problem in a compressor, it means that the compressor is facing the overload problem. You should immediately test your compressor with a meter and if you neglect this issue, your compressor may explode easily.

iii). Noise problem: 

The compressor of air conditioners are mostly quiet enough but if you notice problem there can be an issue. Due to the poor maintenance and insufficient gas supply the compressor may create noise.

  Types of AC and Refrigerator compressors:

The compressors used in AC and refrigerant are same. The Refrigerator system mostly uses Reciprocating, scroll, and, screw compressors whereas the AC uses all five types mentioned here. Basically, there are five kinds of compressors used in AC.

  • The scroll compressors.
  • The rotary compressors.
  • The reciprocating compressors.
  • The screw compressors.
  • The centrifugal compressors.

i). The reciprocating compressors:

These compressors use pistons as a compressing element. A housing contains a piston that is connected to a cankshaft. The piston moves up and down with the help of cankshaft and compresses the air. The reciprocating compressors can single stage, double stage, and, multistage compressors.

ii). Rotary compressors:

The system comprises of a cylindrical housing containing adjustable rotary veins, an inlet, and, an outlet. The veins that are located at the off center drive shaft form compartment and as the shaft moves the compartments get smaller to compress the air and becomes smallest at the outlet.

iii). Centrifugal pumps:

The centrifugal compressors make use of impellers that have curved veins. On rotation the fluid also rotates in the detection of impeller and due to the centrifugal force the fluid flows radially outward. Basically, the motor or impellers impart energy to the fluid that is used to increase the pressure of fluid.

iv). The scroll compressors:

The scroll compressor uses two scrolls. One of them is fixed and the others mobile. The power provided by the motor enables the movement of moveable scroll. Due to the movement of moveable scroll, the area between the scrolls is reduced and the air is compressed. They are either fixed or inverter type.

v). The screw compressors:

The screw compressor contains two helical screws. It is a kind of semi open compressor. The motor powers the screws to rotate and the air is made to flow in between the screws. The air that flows attains high pressure and gets compressed.


Here we have discussed that " How Compressor Works In Ac And Refrigerator?". The purpose of discussion is making the users with their working and problems that may result in disorder. You can use this knowledge to find out the possible solution to any problem that may arise in your AC or refrigerator compressor.

Further, the answer to the question "how do compressors work in AC and refrigerator?" includes the explanation of all the compressor types. There are five types of compressors used in air conditioners and refrigerators and all of them have been well discussed to help the users in making smart choice.

Some compressor problems that have been discussed are related to overheating, mass flow control, noise and overload problems. In order to tackle these problems, understanding these problems is really important.

When it comes to the selection of a compressors, some important factors like compression ratio and type of compressor used in your appliance. So we hope that the above discussion is a satisfying answers to the question "how do compressors work in AC and refrigerator?"

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