What is Scroll Compressor? | How does a Scroll Compressor Work?

What is a Scroll Compressor?

A scroll compressor is a type of compressor which uses spirals or scrolls to compress refrigerant or air. A scroll compressor is also known as a scroll vacuum pump, scroll pump, or spiral compressor. It is most commonly employed in the air conditioner. It also uses as a vacuum pump and car compressor.

Some domestic AC systems and heat pumps and some automotive air conditioners use scroll compressors instead of conventional wobble-plate, reciprocating, and rotary compressors.

These types of positive displacement compressors are completely enclosed (usually surrounded by cylindrical welded steel housing). Maximum scroll compressors are employed in HVAC and refrigeration systems oriented vertically, and scrolls generally installed on the motor shaft top.

Working of Scroll Compressor

A scroll has two spirals or scrolls. One scroll is fixed out of these two scrolls, while the other scroll is moveable. As the scroll rotates, the air is sucked and compressed. The fixed scroll defines the movement path of the rotatory scroll.

The rotatory scroll connects with a crankshaft. This crankshaft gets power from an electric motor. As the electric motor drives the crankshaft, the crankshaft transfers its motion to the scroll and rotates it.

Due to the rotation of the scroll, a vacuum generates between the scrolls. This vacuum generates pressure difference. When the pressure difference produces, the air is sucked from the environment to the compressor.

As the air enters the compressor, the compressor scrolls trap the air. This trapped air can’t go directly from the inlet side to the outlet side. It moves with the scroll’s movement. As the air moves from inlet to outlet, the movement of the scroll reduces the air volume and compresses it. When the air is compressed according to the requirements, it is discharged.

Scroll Compressor Efficiency

The Copeland Scroll compressor’s simple and streamlined design makes it far more efficient. For this reason, the Copeland Scroll compressor is often specified by major manufacturers for systems designed to achieve maximum efficiencies. These compressors don’t use for gas compression.

They have the capability to achieve 100% volumetric efficiency and reduce energy costs for different services. They also eliminate the re-expansion loss that normally occurs with each stroke of the reciprocating model piston. This compressor has no suction valve. Therefore, it doesn’t have energy or pressure losses due to the valve.

Advantages of Scroll Compressor

  1. The scroll compressor has the capability to achieve 100% volumetric efficiency because it doesn’t use a piston for gas compression.
  2. It consumes less energy than the reciprocating compressor.
  3. It has a low energy cost.
  4. Eliminates re-expansion losses typical of each piston stroke encountered in reciprocating compressors. Also, it doesn’t contain intake and exhaust valves (ports), eliminating valve losses.
  5. Due to the small number of moving parts, scroll compressors have a quieter operation than other types of compressors. These compressors are usually 5 to 15 dBA quieter than other types of compressors.
  6. These compressors generate very low vibrations.
  7. As this compressor has low noise and vibration, it doesn’t need a suspension system.
  8. These have long service life because it has less friction.
  9. Much lighter and smaller than other bulky compressors currently in use.

Disadvantages of Scroll Compressor

  1. The main disadvantage of scroll compressors is that they are usually completely sealed and not easy to repair. You can’t disassemble it for maintenance.
  2. This compressor has tough repair, service, and maintenance.
  3. Many reciprocating compressors can support bi-directional rotation. This is usually impossible in the case of scroll compressors.
  4. Incremental capacity control in the system with multiple scroll compressors has often proved tricky.

How to select a Scroll Compressor?

When choosing a compressor, you must choose a single-phase or three-phase motor for your compressor. The selection of the motor varies according to the type of available electrical connection. In most common cases, a single-phase connection is used. Three-phase motors are much more efficient when three-phase connections are available.

Then you should see the secondary parameters such as the operational noise of your compressor. The noise level depends on the operational workplace. We recommend a low noise model if you want to buy a compressor for a household air conditioner.

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