How a Refrigerator Compressor Works & Which Type is Better?

A refrigerator is perhaps the best gift of modern technology to mankind. Never could’ve we imagined a few decades ago of a device that could preserve perishables like milk, fruits, vegetables, or even cooked food for more than a day! Refrigerators made this possible. But do they work on magic? How are they able to keep food cold or even frozen for such a long time? Why doesn’t the food inside it go stale easily?

The answer to all these questions isn’t magic but yes, a similar magical component (metaphorically) which is indeed a very vital part of the refrigerator. It’s called the ‘compressor‘. People tend to have heard the name but are mostly uninformed about its role in the refrigeration process. While a compressor is certainly an important component, it doesn’t work alone in facilitating the refrigeration process. There are other equally important parts of a refrigerator that work in close coordination with the compressor. These include the condenser, expansion valve or capillary tube, and evaporator.

Traditionally, compressors are pretty resilient to damage and are often the last component in refrigerators that cease to work. To attest to the fact, you’ll often find brands boasting generous warranties on their compressors, up to 5-10 times more than the refrigerator itself. But, it’s not always that rosy. In exceptional cases, you may end up with a faulty compressor shortly after a purchase. It is hence advised to only buy refrigerators from reliable brands that have had a long history in the field. If you’re currently in the market to get yourself a resourceful, long-lasting and refrigerator, we’ve compiled a thoroughly researched list of the best refrigerators in India for your reference.

Coming back to the subject, in this article, we’ll discuss the working of a compressor and also try to understand which one is the best for refrigerators to ensure they keep functioning to their optimal efficiency.

How A Refrigerator Compressor Works

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All the other parts of the refrigerator mentioned above first play their role in the refrigeration process. Each performs its function in helping to convert the liquid refrigerant into gaseous form and then back to the liquid state. This process is called evaporation which absorbs heat and creates cold temperatures inside both the refrigerator and the freezer compartments.

Now, the compressor gets activated upon receiving indication from the temperature sensors that the temperature inside has increased beyond a specified desirable level. This indication is meant to break the state of minimum energy consumption and bring back the temperature down to the specified settings in the thermostat. This is how the compressor works after that –

  • The compressor starts up and its pump starts sucking in the cool refrigerant gas from the evaporator.
  • The compressor then starts heating up the gas using a motor which helps compress the gas and increases its temperature. This is why the compressor is named so.
  • The compressed gas then travels to the condenser where the refrigerant is converted to the liquid state by reducing its temperature.
  • The expansion valve reduces the temperature and pressure of the refrigerant, thereby causing half of it to evaporate.
  • The remaining liquid refrigerant is then converted back to gas in the evaporator. The compressor uses this gas to start the refrigeration cycle all over again.

Which Gas in Used in Refrigerator Compressor

Modern-day refrigerator compressors work on the most advanced refrigerant of today’s times, known as Refrigerant R600a. This gas is the most suitable selection for a lot of reasons:

  • It’s a natural gas called Isobutane which does not negatively impact the ozone layer nor is it associated with the greenhouse effect.
  • Only 20g of the gas is used per 130-litre refrigerator. This allows it to create super-efficient refrigerator models.

This is why refrigerator models that use R600a refrigerant are labelled as AAA class, meaning that they display high standard of performance and low power consumption.

Types of Refrigerator Compressors

A compressor isn’t just available in a single type; there are several varieties of it. The different refrigerator compressor types are listed and explained below for your understanding:

1. Reciprocating Compressor

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They are the most commonly used in modern-day refrigerators. These ones come with a piston and cylinder and are so named because the reciprocating motion of the piston helps compress the refrigerant inside the cylinder. A reciprocating type compressor isn’t continually in action but it works in phases thereby minimizing the use of electricity. Most frost-free refrigerators have a reciprocating compressor as opposed to some outdated direct cool variants. (Refer our ‘Direct cool vs. Frost free Refrigerators‘ article for more differences.)

2. Screw Compressor

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These ones are generally utile for industrial refrigeration in factories and have the potential to generate large amounts of pressure using a very small quantity of gas. The refrigerant gets compressed in a screw motor system which has two meshing screws.

3. Scroll Compressor

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It is so named because it’s made of two interwoven scrolls that compress or exert pressure on the refrigerant. One of the two scrolls remains fixed while the other revolves around the fixed one without rotating. When the scroll is in motion, it creates small gaps where the refrigerant gets compressed.

Which Compressor is Best for Refrigerator

Given the differences above between the three compressor types, it can be understood that for domestic or personal refrigerators, reciprocating compressors ideally work the best. They demand the least maintenance as they’re sealed airtight inside a chamber with oil to guarantee long life. This is why they’re also sometimes referred to as ‘hermetically sealed compressors’.

Besides, they also have a simple design just like an engine cylinder which makes them quite user friendly. They also provide a wider range of compression pressure from 10 bar to 250 bar. They’re also proven to lower consumption of energy by at least 10-30% which directly translates to cost savings. Another huge factor that governs the power consumption of your refrigerator is the BEE star rating that it holds. A high star rating combined with a reciprocating compressor makes for one of the most cost-efficient running.

What is the Cost of Compressor for Refrigerators?

Your refrigerator compressor may get faulty or just stop working at times. If you notice any of these in your refrigerator, you’re probably looking at a professional repair session. Here are some common complaints that might start bothering you with regular wear and tear of the compressor over a period of time:

  • Compressor fan stops working – The compressor usually keeps producing a consistent humming sound. This is caused by the motion of the fan which helps to cool down the device and prevent it from overheating. If the fan stops, you might start hearing some weird noises from the fridge; not the humming sound.
  • Compressor starts clicking on/off – If the compressor has a start relay problem or an overload, it might click on and off or not run at all.
  • Refrigerator not cooling– This is a very common compressor problem which comes into light when the fridge doesn’t cool optimally or ceases to cool at all. Although there may be other reasons to this, a failed compressor remains one of the top suspects. We’ve covered some potential reasons why your refrigerator may not be cooling and how to fix it.

If your refrigerator is cooling just right but is bothering you with other problems like leakage, loose door seal and more, the secondary problem might soon cause the compressor to overload thereby causing irreversible damage. These trivial problems can often be solved at home without a professional and hence, must be addressed at the earliest. We’ve put together a collection of the most frequent refrigerator problems and how they can be fixed in this comprehensive write-up.

Summing Up

A compressor, like in any electrical device, is a very important part of a refrigerator. If maintained well, it can last longer and even increase the life span of the fridge, keeping it running efficiently without much trouble.

Samarth is a Mechanical engineer from IIT Bombay with deep understanding of machines and the overall market. Samarth has been building machine from over 8 years so all his reviews on November Culture are first hand expert review. He co founded November Culture along with few other industry experts to provide reviews of daily products.