How Does Refrigeration Compressor Work?

Here’s a simplified explanation of how a refrigeration compressor works:

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Refrigerant Flow: The refrigeration system contains a refrigerant, typically a gas or a liquid, which has properties that enable it to absorb and release heat efficiently. The compressor takes in low-pressure refrigerant vapor from the evaporator coil of the refrigeration system.

Compression: The compressor’s primary function is to raise the pressure of the refrigerant. It accomplishes this by compressing the vapor, reducing its volume while simultaneously increasing its temperature. The compressor contains a piston or a rotating mechanism that compresses the refrigerant.

Discharge: Once the refrigerant has been compressed, it exits the compressor under high pressure as a hot, high-pressure vapor. It is then directed to the condenser coil.

Condensing: In the condenser coil, the high-pressure, high-temperature refrigerant vapor comes into contact with cooler air or a cooling medium, such as water. As a result, the refrigerant releases heat, causing it to condense into a high-pressure liquid.

Expansion: The high-pressure liquid refrigerant flows through an expansion valve or an orifice tube, which regulates the flow and reduces the pressure. This sudden pressure drop causes the refrigerant to expand and partially vaporize, resulting in a mixture of low-pressure liquid and vapor.

Evaporation: The low-pressure refrigerant mixture enters the evaporator coil, which is located in the area to be cooled. The mixture absorbs heat from the surroundings, causing it to evaporate completely into low-pressure vapor.

Return to Compressor: The low-pressure vapor is then drawn back into the compressor to start the cycle again. This process continues as long as the refrigeration system is running, maintaining the desired cooling effect.

Types of Compressors Used in Refrigerator

There are several types of refrigerator compressor commonly used in refrigeration systems. Here are some of the main types:

Piston Compressors

Piston compressors play a crucial role in the operation of refrigerators, providing the necessary compression of refrigerant gas within the refrigeration cycle. These compressors are commonly used in various types of refrigeration systems, including household refrigerators, commercial coolers, and freezers.

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Piston compressors are a type of positive displacement compressor, meaning they work by physically displacing a fixed volume of gas to increase its pressure. Within a refrigerator, the compressor’s primary function is to raise the pressure of the low-pressure refrigerant gas, enabling efficient heat transfer and cooling.

The compressor consists of several key components, including a cylinder, a piston, valves, and a motor. As the refrigerant gas enters the compressor, then piston, driven by the motor, moves up and down within the cylinder. This reciprocating motion creates a vacuum during the downward stroke, drawing the low-pressure gas into the cylinder. During the upward stroke, the piston compresses the gas, significantly increasing its pressure.

The compressed gas is then discharged from the compressor and flows into the condenser, where it releases heat to the surrounding environment, causing it to condense into a high-pressure liquid. This liquid refrigerant then passes through an expansion valve, which reduces its pressure, converting it back into a low-pressure liquid.

The low-pressure liquid enters the evaporator, where it absorbs heat from the refrigerator’s interior, cooling the space. The cycle repeats as the refrigerant continuously circulates through the system.

Piston compressors are known for their reliability and durability, making them a popular choice in refrigeration systems. Their ability to handle varying loads and generate high pressures contributes to their effectiveness in maintaining desired temperatures within refrigerators. However, they can produce more noise and vibrations compared to other compressor types.

Scroll Compressors

Scroll compressors are a type of compressor widely used in refrigeration systems, including refrigerators, due to their efficiency, reliability, and quieter operation.

Scroll compressors utilize a unique design that consists of two spiral-shaped scrolls—one fixed and one orbiting—that fit together. The fixed scroll remains stationary, while the orbiting scroll rotates around it. This design creates a series of crescent-shaped pockets or chambers that gradually decrease in volume as the orbiting scroll moves closer to the fixed scroll.

The compression process in a scroll compressor can be summarized as follows:

Suction: The refrigerant gas enters the outer portion of the scroll compressor through the suction port. As the orbiting scroll rotates, it draws the gas into the outermost pocket.

Compression: As the orbiting scroll continues to rotate, the pockets between the two scrolls decrease in size, causing the gas to be compressed. The gas is trapped in the increasingly smaller pockets and forced toward the center of the scrolls.

Discharge: Once the gas reaches the center of the scrolls, it is discharged through the outlet port at a higher pressure. The compressed gas then proceeds to the condenser, where it releases heat to the environment.

The scroll compressor’s design offers several advantages in refrigeration applications:

Efficiency: Scroll compressors are known for their high efficiency, thanks to the continuous compression process without clearance volumes or re-expansion losses. This efficiency results in lower energy consumption, contributing to reduced operating costs.

Reliability: With fewer moving parts and no reciprocating motion, scroll compressors experience less wear and tear, leading to increased reliability and longer service life. The absence of valves also reduces the risk of valve-related failures.

Quiet Operation: Scroll compressors operate more quietly compared to piston compressors. The spiral motion of the scrolls minimizes vibration and noise, making them suitable for noise-sensitive environments such as households and offices.

Compact Size: Scroll compressors have a relatively compact design, making them ideal for applications with limited space, such as refrigerators. Their smaller size allows for more flexible installation options.

Due to these advantages, scroll compressors have gained popularity in the refrigeration industry. They are commonly found in various types of refrigerators, from residential units to commercial coolers and freezers. The efficient and quiet operation of scroll compressors enhances the overall performance of refrigerators, providing reliable and energy-efficient cooling to preserve food and maintain optimal storage conditions.

Screw Compressors

Screw compressors are another type of compressor commonly used in refrigeration systems, including certain types of refrigerators and industrial cooling applications.

Screw compressors operate based on the principle of positive displacement. They consist of two interlocking helical rotors: a male rotor and a female rotor. The male rotor has a convex shape, while the female rotor has a concave shape. These rotors rotate in opposite directions, creating a sealed pocket between them that progressively reduces in volume as they intermesh.

While screw compressors are widely used in industrial refrigeration and air conditioning applications, they are less commonly found in residential refrigerators due to their larger size and higher cost. However, they are utilized in some larger commercial refrigeration units and walk-in coolers where their capacity and efficiency are beneficial.

Screw compressors offer several advantages in refrigeration applications:

Efficiency: Screw compressors are known for their high efficiency, especially in large-scale cooling systems. They can handle a wide range of operating conditions and maintain stable performance, resulting in energy savings.

Reliability: With fewer moving parts and no reciprocating motion, screw compressors are generally reliable and have a longer lifespan. They are less prone to mechanical wear and vibration-related issues.

Smooth Operation: Screw compressors operate with low noise and vibration levels, contributing to a quieter environment in refrigeration systems.

Capacity Control: Screw compressors often feature built-in capacity control mechanisms, allowing them to adjust their output based on the cooling demand. This capability improves energy efficiency and reduces system cycling.

Centrifugal Compressors

Centrifugal compressors are a type of compressor used in large-scale industrial refrigeration systems, but they are not typically found in residential or small commercial refrigerators.

Centrifugal compressors rely on the principle of centrifugal force to compress the refrigerant gas. They are particularly suited for high-capacity refrigeration applications where a large volume of gas needs to be compressed rapidly.

The compression process in a centrifugal compressor can be summarized as follows:

Inlet: The refrigerant gas enters the compressor through the inlet port. The gas flows into the rotating impeller, which consists of a series of curved blades or vanes.

Acceleration: As the impeller rotates at high speeds, it imparts kinetic energy to the gas, causing it to accelerate outward towards the periphery of the impeller. This acceleration is due to the centrifugal force generated by the rotating impeller.

Diffusion: The high-speed gas then enters a diffuser, which is a stationary component designed to convert the kinetic energy of the gas into pressure energy. The diffuser slows down the gas and directs it into a volute or discharge chamber.

Compression: In the volute chamber, the slowed-down gas is further compressed as it is forced into a progressively smaller space. This compression increases the pressure of the gas.

Discharge: The compressed gas is then discharged from the compressor at a higher pressure and proceeds to the condenser, where it releases heat and undergoes the cooling process.

Centrifugal compressors offer several advantages in large-scale refrigeration applications:

High Capacity: Centrifugal compressors are capable of handling large volumes of gas and delivering high refrigeration capacities, making them suitable for industrial cooling requirements.

Energy Efficiency: These compressors can achieve high levels of energy efficiency, particularly when operating under full load conditions. They are often equipped with variable speed drives to match the cooling demand and optimize energy consumption.

Compact Size: Compared to other compressor types, centrifugal compressors tend to have a relatively compact design, saving space in refrigeration systems.

Low Vibration and Noise: Centrifugal compressors generally operate with lower vibration levels and produce less noise, enhancing overall system operation and user comfort.

Rotary Screw Compressors

Rotary screw compressors are a type of compressor commonly used in commercial and industrial refrigeration systems. While not typically found in household refrigerators, they play a significant role in large-scale cooling applications such as supermarkets, cold storage facilities, and large-scale industrial cooling systems.

Rotary screw compressors operate based on the principle of positive displacement. They consist of two interlocking helical rotors—an actively driven male rotor and a passive female rotor—enclosed within a housing. As the rotors rotate, they trap and compress the refrigerant gas between the rotor lobes and the housing.

Rotary screw compressors offer several advantages in refrigeration applications:

Efficiency: Rotary screw compressors are known for their high efficiency and reliable performance. They provide continuous compression, resulting in smooth and consistent operation, which contributes to energy savings and reduced operating costs.

Capacity Control: These compressors often feature capacity control mechanisms such as slide valves or variable-speed drives. This allows for precise adjustment of the refrigeration capacity to match the cooling load, enhancing energy efficiency and system performance.

Compact Design: Rotary screw compressors have a relatively compact footprint, making them suitable for installations where space is limited.

Quiet Operation: Compared to some other compressor types, rotary screw compressors generally operate with lower noise and vibration levels, providing a quieter working environment.

Rotary Vane Compressors

Rotary vane compressors play a vital role in the functioning of refrigerators by providing the necessary compression for the refrigeration cycle. These compressors are commonly used in various refrigeration systems, including domestic refrigerators, commercial refrigerators, and industrial cooling applications.

A rotary vane compressor consists of a cylindrical housing or casing that encloses a rotor with multiple vanes. The rotor is mounted off-center, creating eccentricity within the housing. As the rotor rotates, the vanes slide in and out of the rotor slots, maintaining contact with the housing wall. This action creates a series of expanding and contracting chambers.

The compression process begins when the expanding chamber, due to the eccentric rotation of the rotor, draws in refrigerant vapor from the evaporator or the low-pressure side of the system. As the rotor continues to rotate; the chamber decreases in volume, compressing the refrigerant vapor. The compressed refrigerant is then discharged into the condenser or the high-pressure side of the system.

One significant advantage of rotary vane compressors is their compact size, making them suitable for applications with space constraints, such as refrigerators. They also offer relatively quiet operation and can provide a smooth and consistent flow of compressed refrigerant.

Additionally, rotary vane compressors are known for their efficiency and reliability, ensuring effective cooling performance in refrigeration systems.

There are different types of rotary vane compressors, including single-stage and multi-stage variants, each designed for specific applications. Single-stage compressors are commonly used in household refrigerators, while multi-stage compressors are employed in commercial or industrial refrigeration systems that require higher pressures and larger cooling capacities.

Rotary-Scroll Compressors

Rotary-scroll compressors are another type of compressor commonly used in refrigeration systems, including refrigerators. They offer several advantages in terms of efficiency, reliability, and compactness, making them a popular choice for modern refrigeration technology.

The rotary-scroll compressor consists of two interlocking scrolls, typically referred to as the stationary scroll and the orbiting scroll. The stationary scroll remains fixed, while the orbiting scroll moves in a circular motion. The scrolls have specific profiles that interlock, creating a series of crescent-shaped gas pockets or chambers.

During operation, as the orbiting scroll rotates, the gas pockets move along the spiral path, gradually decreasing in size. This reduction in volume compresses the refrigerant vapor within the chambers. The compressed refrigerant is then discharged from the center of the scrolls into the condenser or the high-pressure side of the refrigeration system.

One of the key advantages of rotary-scroll compressors is their high energy efficiency. The interlocking scrolls provide a continuous compression process without the need for valves, resulting in minimal gas leakage and improved efficiency. This design also enables the compressor to operate smoothly and quietly, reducing noise levels in refrigeration systems.

Furthermore, rotary-scroll compressors offer a compact and lightweight design, which is beneficial for space-constrained applications such as refrigerators. The absence of pistons, connecting rods, and other moving parts simplifies the construction and reduces the overall size of the compressor. This compactness also contributes to improved reliability and lower maintenance requirements.

Reciprocating Compressors

Reciprocating compressors are special type of compressor commonly used in refrigerators and various other applications. They operate based on the reciprocating motion of a piston within a cylinder to compress the refrigerant and facilitate the cooling process.

The reciprocating compressor consists of a cylinder, a piston, a crankshaft, and a connecting rod. The piston moves back and forth within the cylinder, driven by the rotation of the crankshaft. As the piston moves downwards, it creates a vacuum in the cylinder, drawing in refrigerant vapor from the evaporator or the low-pressure side of the refrigeration system.

Upon reaching the bottom of its stroke, the piston reverses direction and moves upwards, compressing the refrigerant vapor within the cylinder. This compression increases the pressure and temperature of the refrigerant. The compressed refrigerant is then discharged into the condenser or the high-pressure side of the system.

Reciprocating compressors are known for their robustness and reliability. They can handle high-pressure applications and are capable of providing the necessary compression for a wide range of refrigeration requirements.

Their design allows for precise control over the compression process, making them suitable for refrigeration systems that require accurate temperature regulation.

One advantage of reciprocating compressors is their ability to generate high compression ratios, resulting in efficient cooling performance. They are particularly suitable for applications with varying cooling loads, as they can modulate their capacity to match the refrigeration demand.

This modulation can be achieved through the use of technologies such as variable speed drives or multiple cylinders.

Hermetic Compressors

Hermetic compressors are a type of compressor commonly used in refrigerators. They are named “hermetic” because they are sealed within a single housing, which means the compressor and motor are contained in a single unit. This design offers several advantages in terms of convenience, efficiency, and reliability.

In a hermetic compressor, the motor and compressor are integrated and sealed within a single housing, often made of metal or other durable materials. This sealed design eliminates the need for external shaft seals or couplings, ensuring that the refrigerant remains contained within the system and preventing any leakage.

The hermetic compressor operates using similar principles as other compressor types, such as reciprocating or rotary compressors. It compresses the refrigerant vapor by creating a pressure difference and forcing it into a high-pressure state. The compressed refrigerant is then discharged into the condenser, where it releases heat and undergoes the cooling process.

One significant advantage of hermetic compressors is their compact size and simplified installation. The compressor and motor are pre-assembled as a single unit, making it easy to integrate into the refrigerator system. This compactness is especially beneficial for domestic refrigerators, where space is limited.

Hermetic compressors are also known for their high efficiency. The sealed design minimizes refrigerant leakage and ensures optimal compression efficiency. The integration of the motor and compressor allows for direct power transfer, reducing energy losses and improving overall efficiency.

Moreover, hermetic compressors offer enhanced reliability. The sealed housing protects the compressor and motor from external factors such as dust, moisture, and contaminants, reducing the risk of damage or malfunction. This design also eliminates the need for regular lubrication or maintenance, making the compressor virtually maintenance-free.

Semi-Hermetic Compressors

Semi-hermetic compressors are a type of compressor commonly used in commercial and industrial refrigeration applications, including large-scale refrigerators and freezers. They are called “semi-hermetic” because they have a housing that can be opened for servicing and repair, unlike hermetic compressors which are fully sealed.

In a semi-hermetic compressor, the motor and compressor are housed within a common casing, which can be opened for maintenance or component replacement. This design allows for easier access to the internal components, such as pistons, valves, and bearings, making servicing and repair more feasible compared to hermetic compressors.

The operation of a semi-hermetic compressor is similar to other compressor types, such as reciprocating or rotary compressors. It compresses the refrigerant vapor by creating a pressure difference and forcing it into a high-pressure state. The compressed refrigerant is then discharged into the condenser, where it releases heat and undergoes the cooling process.

Semi-hermetic compressors offer several advantages for commercial and industrial refrigeration applications. One key advantage is their flexibility in terms of capacity modulation. Semi-hermetic compressors can often be equipped with multiple cylinders, allowing for varying levels of capacity based on the refrigeration demand. This modulation capability is beneficial for applications with changing cooling loads.

Another advantage of semi-hermetic compressors is their enhanced durability and serviceability. The ability to open the housing for maintenance and repairs makes it easier to replace worn-out components, extend the compressor’s lifespan, and reduce downtime. Additionally, semi-hermetic compressors are designed to handle higher pressures and larger cooling capacities, making them suitable for demanding refrigeration systems.

How to Choose Refrigerator Compressors?

When choosing a refrigerator compressor, there are several factors you should consider ensuring you select the right one for your needs. Here are some key considerations:

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Refrigerator Type: Determine the type of refrigerator you have or plan to build. Compressors are available for various types, including household refrigerators, commercial refrigerators, wine coolers, and more. Each type may have specific requirements.

Cooling Capacity: Evaluate the cooling capacity you require for your refrigerator. This is typically measured in BTUs (British Thermal Units) or Watts. Consider the size of the refrigerator and the amount of cooling it needs to maintain the desired temperature.

Compressor Size: Compressors come in different sizes, and the size you choose depends on the cooling capacity and available space in your refrigerator. Ensure that the dimensions of the compressor fit within the available space.

Efficiency: Look for compressors that offer high energy efficiency. Energy-efficient compressors can help reduce power consumption and lower your operating costs in the long run. Look for compressors with high Coefficient of Performance (COP) ratings.

Noise Level: Consider the noise level of the compressor. Compressors can produce varying levels of noise during operation, so choose one that meets your preferences, especially if noise is a concern in your environment.

Reliability and Durability: Look for compressors from reputable manufacturers known for their reliability and durability. Read reviews and check the warranty provided to ensure you are getting a reliable product.

Compatibility: Ensure that the compressor you choose is compatible with your refrigerator system, including the refrigerant type and any additional components required for proper operation.

Price: Consider your budget and compare prices from different suppliers. However, remember that quality and suitability for your needs should be the primary factors when making a decision.

It is advisable to consult with refrigeration professional or a supplier specializing in refrigeration equipment to ensure you make an informed choice based on your specific requirement.

List of Refrigerator Compressor Manufacturers

Here is common list of refrigerator compressor manufacturers:

• Danfoss Compressors
• LG Compressors
• Embraco Compressors
• Samsung Compressors
• Whirlpool Compressors
• GE Compressors
• Frigidaire Compressors
• Bosch Compressors
• Haier Compressors
• Panasonic Compressors
• Hitachi Compressors
• Hisense Compressors
• Electrolux Compressors
• Mitsubishi Compressors
• Toshiba Compressors

These manufacturers produce a wide range of refrigerator compressors that are used in various refrigerator models. Each manufacturer may offer different compressor models with varying capacities, efficiency levels, and features.

It’s important to check with specific manufacturers or retailers for the availability and compatibility of compressors for a particular refrigerator model.

FAQs (Frequently Asked Questions)

Here are some frequently asked questions about the types of refrigerator compressors:

What is a compressor in a refrigerator?

Refrigerator compressor is a vital component responsible for circulating the refrigerant throughout the cooling system. It compresses the low-pressure refrigerant vapor, raising its temperature and pressure before sending it to the condenser for further heat exchange.

What is the difference between a reciprocating compressor and a rotary compressor?

The main difference lies in their working mechanisms:

Reciprocating compressors use a piston that moves back and forth to compress the refrigerant. The piston creates pressure by decreasing the volume of the cylinder. They are simple in design and suitable for smaller applications.

Rotary compressors employ rotating mechanisms, such as vanes or screws, to compress the refrigerant. The rotation creates a continuous compression process, eliminating the need for pistons. Rotary compressors are typically more efficient, quieter, and often found in larger refrigeration systems.

Which type of compressor is more energy-efficient?

Generally, rotary compressors tend to be more energy-efficient compared to reciprocating compressors. The continuous compression process and the absence of piston friction in rotary compressors result in smoother operation and reduced energy consumption. However, the specific efficiency depends on the design, size, and overall system of the refrigerator.

Summing Up

Now, we can hope that you have been fully aware about different types of refrigerator compressor along with their pros and cons with ease. If this content is helpful for you, then please share it along with your friends, family members or relatives over social media platforms like as Facebook, Instagram, Linked In, Twitter, and more.

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