Rotary Vs. Reciprocating Compressor – Which is Better for AC and Refrigerator?

By Consumer Advise Team
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If you feel bewildered about the difference between rotary and reciprocating compressors for choosing your new AC or refrigerator, you have come to the right place.

Before choosing a rotary compressor or reciprocating compressor, you should be well acknowledged of the features of an ideal compressor! There’s no such thing present in the world that can be rightly judged without using it. The same thing goes for the compressor.

However, for your better understanding, make it clear that the most efficient compressors are silent, tightly packed, work all day without electricity, and never cease to run. To select between rotary vs. reciprocating compressors, first, understand the fundamental differences between their working techniques and their applications.

As these two compressors have the single aim of creating compressed air, you need to choose the most suitable one for ascertaining the best performance. This guide is particularly beneficial for selecting the best air compressor to support your operation. 

Rotary vs. Reciprocating Compressor comparison

Rotary vs. Reciprocating Compressor comparison

Point of DifferenceRotary CompressorReciprocatory Compressor
Flow of AirIn the rotary compressor, the rate of airflow is relatively high as 3000 m3/ minute.In the reciprocating compressor, the air-flow rate is low as 300 m3/ minute.
Air supplyFor effective running of the rotary compressor, a continuous air supply is required.In a reciprocating compressor, the supply of air is used for intermittent purposes.
Operation SpeedThe speed of operation in the rotary compressor is high.The operational speed of the reciprocating compressor is low.
Compressor sizeConsidering the refrigerant discharge, the size of the rotary compressor is small.For a similar kind of discharge, the size of the reciprocating compressor is relatively large.
Maximum pressureHere, the maximum discharge pressure is limited to 10 bar.For reciprocating compressors, the highest delivery pressure is 1000 bar.
As the delivered air doesn’t have direct contact with lubricating oil, the discharged air is relatively clean and dust-free.Rotary compressors are best used for high air discharge.Reciprocating compressors are best suited for low air discharge.
Operating MediumA rotary compressor is mostly used for compressing air or other gases.A reciprocating compressor is used for liquid or mixed medium.
Primary costHere, the primary cost is relatively low.The initial cost of a reciprocating compressor is relatively high.
Maintenance RequirementThe rotary compressor needs low maintenance.The reciprocating compressor requires higher maintenance.
Nature of delivered airAs the delivered air doesn’t have direct contact with lubricating oil, the discharged air is relatively clean and dust-free.As the delivered air directly connects with lubricating oil, the supplied air is not fully clean without a filter.

How can a rotary compressor help you?

Rotary compressors are one of the popular compressors across multiple industries. Here the compression process works by continuous sweeping movements. Using a positive displacement mechanism, the rotary compressor mechanically squeezes or compresses fluid to reduce its volume and increase its pressure.

Alternatively known as rotary screw compressors, these machines use two helical screws or asymmetrical rotors for air compression. Since the middle of the 1900s, this famous screw compressor has been used in every stationary application.

With time, these air compressors have become more economical and widely accepted by various industries. Presently, numerous global companies have started using this screw compressor in varying industrial applications for efficient air compression. 

The working method of the rotary compressor

Talking about the working principles of the rotary compressor, first know about its primary construction. For the effective functioning of the compressor, there’s a cylinder with an absorption port and an emission port. The cylinder also consists of a roller inside of it.

working rotary compressor

The coolant gets trapped whenever the fluid is introduced into the compartment between the rotor and cylinder. As the volume of the chamber starts decreasing, the liquid or air gradually gets compression. Finally, the high-powered fluid gets released from the discharge point. 

Advantages of rotary compressor

Before comparing rotary and reciprocating compressors, first, understand the value of each compressor in daily uses. From machine handling to spray painting, rotary compressors are widely used across numerous industries due to the immense benefits they provide. Here are a few advantages of relying on rotary compressors. 

  • As the airflow rate is excessively high in the rotary compressor, it generates relatively more power to handle tools than typical machinery can do. As a result, with the efficient use of electricity, the overall process gets fastened.
  • Another prominent advantage of the rotary compressor is that it is well-balanced, lightweight, and less noisy. 
  • There is a rare case of accidents with machines that use rotary air compressors. Hence, they are incredibly convenient and safe to use for air delivery systems for any purpose. 
  • Rotary compressors are designed in such a way that they require less initial cost as well as less maintenance cost. As the latest compressors come up with less than 70% of necessary parts, the overall maintenance costs reduce drastically. 
  • In extremely high or low temperatures, where no other energy form is allowed for safety reasons, the rotary compressors can efficiently function at your convenience. Thus, rotary air compressors are all-weather-purpose tools that can effectively work in any situation. 
  • Compared to other compressors, rotary compressors require less oil for lubrication. Thus, the released output comes with no oil or dirt.
  • Being an energy-efficient air compressor, the rotary compressor prioritizes less heat generation. Thus, they conserve energy very well than typical air compressors. 
  • If you want any long-lasting air compressor, there’s no alternative to rotary compressors. You can rest assured of this particular compressor for years without worrying about capacity reduction.

Rotary Compressor Limitations

  • Compared to reciprocating compressors, rotary compressors need higher initial investments. 
  • If you use the reciprocating compressor for running home appliances like AC, you should operate them for specific periods every week. That’s not feasible for most households as many of them don’t need AC units all the time. Thus, rotary compressors are best used for industrial usage.  
  • Considering stages, the discharged air pressure is comparatively low than other air compressors. 
  • Less flexibility in air compression.
  • As the capacity is low, you can’t expect efficient output without skilled maintenance. 
  • For the effective functioning of the rotary compressors, a clean environment is mandatory and that can’t be possible all the time. 

Best uses of rotary compressors

The rotary air compressor is best used in industries like food processing, paint lines, and others for running high-power machinery that requires a sturdy and continuous flow of fluids. Observing the extreme weather conditions worldwide, there’s have been increased usage of air-conditioning or refrigerator systems in large spaces.

Thus, some brands install rotary compressors in most large-volume appliances to cool room for an extended period. Rotary compressors are primarily suitable for commercial areas that need to operate high-forced air tools like pneumatic pumps, impact wrenches, sandblasting operations, etc. 

Why is a reciprocating compressor important?

From the name, you can understand that reciprocating compressors work the same as automobile engines do. Alternatively named as a piston-type air compressor, this particular compressor is best used for small-scale applications that require frequent compressed air usage.

This compressor consists of an array of cylinders, valves, and regular pistons that help in efficient gas compression for daily-use applications with the benefit of easy maintenance. From small business establishments to household purposes, these compressors use positive displacement technology and work for meeting occasional machinery utilization.

Using the back-and-forth motion, the insider piston creates a reciprocating mechanism and helps air to draw inside, compress and discharge outside. 

How does a reciprocating compressor work?

The working mechanism of the reciprocating compressor depends on two integral parts, named – cylinder, and piston. Going by the name, the piston moves up and down inside the cylinder to compress the refrigerant. Hence, it is called reciprocating motion. The duo valve set helps in air absorption and exhaustion. 

reciprocating compressor

With the pistons moving towards the downside, the suction gas is enforced for air compression and volume reduction into the chamber. As soon as the compressor runs, the piston makes a downward movement to expand the vacuum. It takes the refrigerant inside. This procedure will continue until the piston touches the lowest point of the cylinder for making an end of the suction cycle. 

With a further continuation, the compressor will let the piston go upward inside the cylinder and compress the refrigerant. Thus, there is seen a reduction in vacuum and an increment in the air pressure. The process will continue until it reaches a point where the pressure of the cylinder goes higher than the discharge pressure of the refrigerant.

This is when the discharge valve will be enforced to open and displace the compressed air or refrigerant from the cylinder through the discharge valve. This is how the compression cycle keeps repeating until the refrigerant comes out. 

Advantages of reciprocating compressors

To slim down your choice in-between rotary vs. reciprocating compressor, you want to clear out for what purposes the reciprocating compressor is befitting most. To assuring the utmost flexibility of intermittent usage, reciprocating compressors are widely used not only in home appliances or small workshops but deliberately applied in oil, gas, and chemical industries. Installing reciprocating compressors over others has many advantages. A few of them are described below. 

  • As compared to rotary compressors, reciprocating air compressors can create higher pressures Due to the presence of multiple cylinders and pistons inside the mechanism. In every temperature control application, this particular compressor is preferred for producing pressures ranging between 60 to 30,000 PSI.
  • As mentioned previously, reciprocating compressors can best perform in irregular usages. For adopting a unique style of operation, reciprocating compressors can maintain efficiency whenever run, if needed. Just like other compressors, it doesn’t have to run continuously for high efficiency. Thus, using reciprocating compressors is excellent for conserving energy over rotary air compressors.
  • The most significant advantage of choosing an AC or a refrigerator with a reciprocating compressor is that you can seamlessly avail yourself of this along with its components in the market against cost-effective prices.
  • As the components of the reciprocating compressor are designed with simple mechanisms. They need less maintenance, and you need not worry about maintaining the inside parts like pistons and shafts. 
  • This particular compressor needs significantly less energy to function at very high pressure efficiently. Hence, this feature will be beneficial for every intermittent usage where forceful pressure is required for efficient machinery performance. 
  • From oil-free base to oil-soaked placement, reciprocating compressors come with every variety to ensure you a flexible operation in a wide range of industries. Your preference for using reciprocating compressors can’t be compromised for the sake of oil contamination in the process. 
  • Unlike other compressors, reciprocating compressors can be placed in any indoor and outdoor environment regardless of their cleanliness. 
  • If you want an economical compressor for high-pressure fluid generation, you can entirely rely on reciprocating compressors as it needs less capital investment than other heavily used air compressors.

Limitations of reciprocating compressor

In addition to countless benefits, reciprocating compressors have a few limitations also. These are discussed below. 

  • While in operation, the reciprocating compressors sometimes start creating loud noises, which extend up to 100 dB.
  • Contrary to other popular compressors, reciprocating compressors have lower longevity. 
  • The speed limit decreases with constant damage to the cylinder, piston ring, and other components, and the overall power generation process becomes less effective.
  • Considering multiple parts, components, and complicated working structures, reciprocating compressors require extreme maintenance.
  • High up-keeping cost prevents users from installing this particular compressor for the smooth running of home appliances. Thus there’s less reliability seen in choosing this air compressor over others. 

Best uses reciprocating compressors

Reciprocating compressors are generally used in those applications where high pressure, and a short burst of discontinuous airflow, are required. Thus, it’s the ultimate choice for householders, DIYers, construction businesses, and small-scale shops for dust cleaning, air-brushing, running air-borne tools, sandblasting, tire inflation, and many more tasks.

The reciprocating compressor acts as the one-stop solution, for food and beverage plants, automobile service stations, drilling operations, and small tool applications to other commercial usages.

The most significant advantage of using a reciprocating compressor in daily application is that it won’t get damaged for intermittent usage or running beneath its highest capacity. Industrialists suggest extending the reciprocating air compressor to 50% greater than its required air volume to allow the compressor to run appropriately and eliminate uncontrolled heat production. 

Rotary vs. reciprocating compressor: Which is better?

So, which compressor would you choose for your AC and refrigerator?

After studying the working principles, advantages, disadvantages, and difference points of reciprocating and rotary compressors, you have acquired in-depth knowledge of this heavy-weighted field. There’s no doubt that this article has helped you to pick up your most suitable AC/refrigerators and save your hard-earned money.

Just like any other materialistic component, both compressors have their benefits and limitations. You need to find out the better option for you, considering several parameters such as speed, longevity, usage, capacity, performance, and many others. 

In conclusion for reciprocating vs rotary compressors, we can say that the first one is best for running an air-conditioning or refrigeration system in smaller spaces (home or newly opened business). Also, if you are dealing with tight in the pocket, simply go for appliances with reciprocating compressors and satisfy your needs.

As all the places don’t require continuous airflow, the air conditioners with reciprocating compressors can be efficiently used for meeting intermittent purposes without hampering their durability. However, for cooling a wide-reaching space like industrial plants need to install an Air conditioning system with rotary compressors.

Being a mechanical engineer with enormous field experience with both of these compressors, I can say that it is best to depend on your specific requirements. Thus, it’s wise to understand the primary usage first and then select the ideal option of compressors. 

Inverter compressor – an upgrade to rotary & reciprocating compressors

By now, you have clearly understood the pros and cons of each of the compressors. Hence you can choose the right kind of air conditioning system for meeting your purpose. From considerable market research, it’s evident that most refrigerant brands prefer to install reciprocating compressors in home appliances.

inverter compressor system in a refrigerator

In contrast, large industrial customer base brands choose rotary compressors in air conditioners for cooling large commercial spaces at a stretch.

While you are more concerned about the difference between rotary and reciprocating compressors, here comes the inverter compressor, an advanced variant, to make rotary and reciprocating compressors a bit more capable and efficient.

The inverter ACs lead to reduced depletion of parts, elimination of sudden electricity fluctuations, and ensure noiseless operation. Although the inverter compressor is relatively more expensive than the conventional compressors, manufacturers use this compressor in refrigerators and AC for saving electricity and make your every penny worthwhile.

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