Variable Displacement and Variable Speed Drive Compressors

 

Compressed air systems are a vital component of many industrial processes, and they come in a variety of types and designs. Two of the most common types are variable displacement and variable speed drive compressors. While both types are designed to optimize system efficiency, there are some important differences between them. In this article, we will discuss the differences between variable displacement and variable speed drive compressors.

Variable Displacement Compressors

Variable displacement compressors, also known as variable output compressors, are designed to adjust the output of compressed air to meet the changing demands of the system. They achieve this by varying the volume of the compression chamber. The compressor can adjust the displacement of the chamber by using either a mechanical or electronic mechanism. The mechanical mechanism uses a swash plate to vary the angle of the piston, while the electronic mechanism uses a solenoid valve to control the displacement of the compressor. The result is a compressor that can adjust the output of compressed air or refrigerant to match the changing demands of the system.

Variable Speed Drive Compressors

Variable speed drive compressors, on the other hand, are designed to adjust the speed of the motor to match the changing demands of the system. They achieve this by using a variable frequency drive (VFD) to control the speed of the motor. The VFD adjusts the frequency of the electricity supplied to the motor to control its speed. The result is a compressor that can adjust the output of compressed air or refrigerant by varying the speed of the motor.

Differences between Variable Displacement and Variable Speed Drive Compressors

While both variable displacement and variable speed drive compressors are designed to optimize system efficiency, there are some important differences between them.

With a variable displacement compressor, the motor and airend are spinning at the same speed, but due to the reduced load, less energy is needed. Variable speed drive compressors, on the other hand, adjust the speed of the motor (and therefore the airend) to match the demand, resulting in even more efficient operation and lower energy consumption.

Cost-wise, although the Variable Speed compressors is more cost efficient, it also comes with a larger price tag, so that exact savings (if any varies). We would recommend getting a complete compressed air audit done to see which system is best for you.

Conclusion

In conclusion, both variable displacement and variable speed drive compressors are important components of compressed air systems. While they are both designed to optimize system efficiency, they have some important differences. Variable displacement compressors are better suited to applications with varying demands, while variable speed drive compressors are better suited to applications with consistent demands. Additionally, variable displacement compressors are generally more expensive but more reliable than variable speed drive compressors. By understanding the differences between these two types of compressors, you can select the one that is best suited to your application.