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Compressor Controls and How to Enhance Compressed Air System Efficiency

Atlas Copco Smart Factory Compressor Technique

Whatever the industry, efficient operation of compressed air systems is crucial in reducing operating costs and ensuring stable operation. Here, compressor controls play a vital role in achieving high performance and efficient operation of compressed air systems. In this wiki, we will explore compressor controls, their types, and their importance in maximizing the efficiency of compressed air systems. 

Compressor Controls

Elektronikon® Nano™ controller buttons

Compressor controls refer to the tools that let you monitor and adjust how much power your air compressors use. They're like the dials and switches that help you manage the output of each compressor. This is important because it allows you to match the air supply with what your system needs, saving energy

 

Compressor control systems, on the other hand, are the whole setups that include multiple compressors working together to supply air to a plant or facility. These systems use a network of controllers that connect the individual compressor controllers. Think of it like a chain of communication between the compressors.

 

These controls make decisions about when to start or stop compressors, adjust their output, or even change their speed. 

The key difference is that compressor controls focus on the adjustments of individual compressors, while compressor systems involve coordinating multiple compressors to work together efficiently. Both are essential for saving energy and ensuring your system runs smoothly. 

System controls and compressor type selection are the most crucial factors affecting system performance and efficiency. Compressor technology has evolved to include start/stop, load/unload, modulating inlet control, and other controls, while electric motors and controllers have been developed to satisfy the demand for precise control. Special approaches are available for controlling multiple compressors in a system comprising fixed-speed and variable-speed drive (VSD) compressors.

Types of Compressor Controls

There are several types of compressor controls available, including:

1. Start/Stop Controls

The start/stop control system turns on and off the motor driving the compressor in response to the discharge pressure and is best suited for low-duty cycles in the 25hp and under range. 

2. Load/Unload Controls

Load/unload control is suitable for almost any type of compressor and requires storage receiver volume, switching the compressor to unload at the unload pressure setpoint and returning it to full capacity once the lower load pressure is reached.  

3. Modulating Inlet Controls

Modulation, also known as inlet valve modulation, matches the compressor's capacity with air usage by throttling off the air inlet as pressure rises. However, this method can cause poor part load performance and requires significant air receiver storage.  

4. Dual Control

Dual control combines modulation and load/unload control to provide better part load performance and reduce storage receiver volume.  

5. Variable Speed Drive (VSD) Control

VSD control adjusts the speed of the compressor motor to match air usage requirements precisely. This allows for better energy efficiency and part load performance, as the compressor can operate at varying speeds to meet demand. 

6. Network Controls

Network controls form a chain of communication between the on-board compressor controllers and coordinate compressor functions to optimize air usage. 

Importance of Compressor Controls

Elektronikon® Nano™ controller buttons

Compressor controls are essential for ensuring that air compressors operate at a high level of efficiency without any breakdowns

 

Modern air compressor controllers are highly advanced systems with high processing power, advanced connectivity options due to the need for controlling compressed air systems which are complex in nature. Sensors and electrical components make up the control system, allowing for monitoring and adjusting of the power output of the motor. 

PLCs and HMIs are used for automatic processes, and variations in the speed of the driver can affect the compressor’s output. Compressor control systems have the ability to modulate the inlet valve, throttle gas intake, and maintain a certain pressure, ensuring that compressor output meets expectations. Automatic shutdowns can be initiated in the event of a component failure or unsafe working conditions. Networked controls are utilized in industries that need more than one compressor, with one compressor assuming the role of the master and the others taking on the functions of subordinates. 

Compressor Control Methods

The efficiency of an air compressor greatly depends on the control method used, and there are several methods available for various types of compressors. 

 

For oil-injected rotary screw compressors, the inlet valve modulation, also known as modulation, is one control method that matches the compressor's capacity with air usage by throttling off the air inlet as pressure rises. However, this method can cause poor part load performance and requires significant air receiver storage.

Load/unload control, on the other hand, is suitable for almost any type of compressor and requires storage receiver volume, switching the compressor to unload at the unload pressure setpoint and returning it to full capacity once the lower load pressure is reached.

 

Variable speed drive controls vary the speed of the motor and airend through a frequency drive to provide nearly proportional flow to power ratio at part load.

 

For centrifugal compressors, the blowoff valve and bypass valve are the traditional options for controlling air demand and surge while the unloading control reduces power consumption to 10 to 20% of full load power consumption. 

Common Questions about Compressor Control Systems

What are compressor control systems?

Compressor control systems are systems that allow for monitoring and adjustments to the power output of air compressors, ensuring their stable operation and energy efficiency.

How do compressor control systems work?

Compressor control systems work by utilizing sensors and electrical components to monitor and adjust the power output of the motor, ensuring that compressor output meets expectations.

What are the benefits of compressor control systems?

Compressor control systems offer several benefits, including stable operation, energy efficiency, and automatic shutdowns in the event of a component failure or unsafe working conditions.

What factors should be considered when selecting a compressor control system?

The type of control system required depends on air demand and the type of compressor in use. A simple control system may be sufficient for a system with one compressor and a steady demand, whereas a more complex system with multiple compressors, varying demands, and different end-uses may require a comprehensive control system.

How can compressor control systems be optimized for efficiency?

Compressor control systems can be optimized for efficiency by selecting the appropriate control method for the type of compressor in use and ensuring that the system is properly maintained and monitored.

Contact Us Today

If you have any questions about compressor controls or need assistance with how to optimize the efficiency of your compressed air system, contact Atlas Copco today.

Our team of experts can help you select the right compressor control system for your needs and ensure that your system operates efficiently, reliably, and cost-effectively.

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A collection of articles dedicated to explaining everything there is to know about compressed air, compressors, air treatment and the system that surrounds it.