Which is the Best AC Compressor: Rotary or Reciprocating?

by | Feb 6, 2019

Air conditioners are one of the fast moving home appliances currently in the Indian market.

Being a developing country with a burgeoning middle class with increasing disposable income, these devices are no more considered as a luxury but a necessity.

With the temperature clocking constantly above 40 degrees in the summer and touching new lows every winter, the need to have an air conditioner at your home/office has become a must.

In this article, we’ll discuss in detail one of the single most important component of an air conditioning system – the compressor.

The presence of a good compressor can be a make or break situation in an air conditioner purchase, so we feel its apt to go a bit technical in this post to let you understand the importance of the same.

Air Conditioner

An air conditioner is an appliance used to modify the indoor air conditions such as humidity, temperature, moisture level etc.

The primary aim of a home/office air conditioner is to increase the comfort level for human beings inside a closed space.

There are different types of air conditioners available in the market catering to different use cases.

The regular split and window ACs are suitable for the small to medium sized living spaces and office rooms.

Cassette type ACs are suitable for air conditioning spaces with more occupants inside.

For cooling a large volume of space, centralized AC systems are employed.

Working of an Air Conditioner

Before getting into the specifics of an AC compressor unit, let’s discuss how does an AC work.

The main three components of an air conditioning system are compressor, condenser and evaporator.

working-of-ac

The compressor and condenser are the outdoor units and the evaporator is what you see inside your home/office.

  • The compressor compresses the refrigerant (in gas from) to a smaller volume resulting in the increase in its temperature.
  • This gas is then fed into the condenser which helps in releasing the heat to the outside.
  • From the condenser, the gas flows via an expansion valve, at the end of which the gas turns into a liquid state.
  • The liquid refrigerant finally enters the evaporator and absorbs heat from the interior to make the surroundings cooler.

Compressor

A compressor is a mechanical device which increases the pressure of a gas by bringing about a reduction in its volume.

In refrigeration and air conditioning, the quality and type of compressors used significantly determine the performance and efficiency of the system.

When it comes to the air conditioners which we are familiar to in our homes and offices, the two main types of AC compressors used are reciprocatory and rotary compressors.

Reciprocating Compressors

Reciprocating compressors, as you might have already guessed from the name itself, works similar to the one in an automobile engine.

reciprocating-compressor

It consists of the regular piston and cylinder setup with the piston moving back and forth to compress the fluid inside.

There can be multiple cylinders inside a reciprocating compressor and all of them can work in tandem to ensure excellent efficiency.

Rotary Compressors

Rotary compressors consist of a pair of specially designed rotors rotating in the opposite directions.

rotary-compressor

These rotors have a very little clearance between them and the fluid attains high pressure inside.

The most recent iteration of the rotary compressor is the scroll type system.

This compressor consists of a static central coil and a rotating coil on top.

The rotating coil pushes to the fluid into the centre of the fixed coil, thereby increasing its pressure.

Comparison Between the Reciprocating and Rotary Compressors

There are distinct advantages and disadvantages for both of these compressors.

Choosing one from the other is a really difficult task and solely depends on your usage scenario.

Advantages of a Reciprocating compressors

  • Increased efficiency

Since multiple piston and cylinder arrangements can be set up inside the compressor, extremely higher pressure can be attained.

  • Easy maintenance

Since piston and shaft mechanism is common and easily disassembled, there is no issue in fixing problems, if any pops up.

Disadvantages of Reciprocating Compressors

  • Vibration and Noise issues

Since the compressor consists of multiple moving mechanical elements inside, the level of noise and vibration is high compared to other compressors.

reciprocating-compressors-pros-cons

Advantages of Rotary Compressors

  • Less noise and vibration

The rotating sections inside the rotary compressor feature minimal moving parts, resulting in considerably lesser noise and vibration while operating.

  • Best for large scale air-conditioning applications

Rotary compressors can operate under a much wider power range and pressures than reciprocating compressors, making it ideal for businesses and industrial applications.

Disadvantages of Rotary Compressors

  • Have to be used continuously for durability and better performance.

Since home Ac usage is periodic and not regular, these compressors are better suited for offices and factories with a fixed time schedule.

  • Comparatively expensive than reciprocatory compressors.

rotary-compressor-pros-cons

Which is the best: Rotary Compressor or Reciprocating Compressor?

If you are looking for an Air Conditioner for your home or office with small space, the reciprocating compressor is the best choice for you. For cooling a large space with regular continuous working for long hours, look for an AC with a rotary compressor.

Inverter Compressors

Inverter technology is a fairly recent advancement in the Indian home appliance market.

Inverter compressors are not an entirely new type of compressor but a technology on top of the existing compressors to make them more power efficient and capable.

DC inverter is used to control the speed of the compressor so that the AC can precisely adjust the temperature.

Also, inverter ACs have a variable-frequency drive, which never shuts off the compressor totally.

This results in less wear and tear to the parts, no sharp fluctuations in current, and overall quieter and silent operation.

Inverter compressor ACs may be a bit expensive than traditional ACs but it’s worth every single additional penny.

Final Thoughts

This concludes our short explainer article about various types of compressors used in air conditioner systems available in the market.

There are merits and demerits for each one of them, but now with a better understanding of these components, you can make an informed choice depending on your use cases.

If you have any doubts regarding the same, please let us know in the comment section below and we’ll be happy to answer your queries.

Thanks for your time on our website and have a great day ahead!