Variable Speed Compressors for Improved Energy Efficiency

L75RS family variable speed drive compressors

Energy efficiency is one of the most important factors all businesses are concerned with. The more efficient your air system, the lower your energy consumption and the cheaper your energy bill!

A vast amount of the energy that is lost in a factory or plant is due to wasted energy in an air compressor installation. This can have a huge effect on energy costs, raising your bills and making your cost of ownership high. Various technologies have been developed to ensure that compressed air systems are performing as efficiently as possible, one such technology is variable speed drives (VSD).

variable speed drive compressor schematic

Ultima uses variable speed drive for ultimate efficiency

What is VSD?

Variable speed drive (sometimes called variable frequency drive or regulated speed) compressors use an intelligent drive system to continuously alter the motor speed to match the air demand. This drive controls the speed (RPM) of the unit depending on the demand, fluctuating the amount of power that is used to perfectly match the output required. When the demand slows, the compressed air system will reduce motor speed and thus the power consumption is also reduced.

Fixed vs Variable Speed Drive Compressors

Traditional air compressors are fixed speed, meaning they run at a constant and consistent speed. This produces a fixed amount of compressed air per minute. There are many benefits to fixed speed compressor technology if your compressed air demand is constant and unchanging. However, this isn’t always the case. As fixed speed compressors are always operating at full-throttle, if all of the output is not required then energy is being wasted.

Furthermore, fixed speed compressors run unloaded as the stress of an engine start-up would put pressure on the motor. This can be a waste of energy as the machine is running without producing any compressed air. Variable speed compressors avoid this issue by matching the output with the demand created. By simply producing the exact amount of air being used by the downstream equipment, variable speed compressors help to improve plant efficiency.

Watch this video to see how a fixed speed compressor can be sequenced with a variable speed machine to precisely match output with network demand to save energy.

Benefits of a Variable Speed Compressor

No need to unload - the ability to start and stop under full system pressure.

Reduced power costs - no loss of energy through running unloaded.

Reduced power surges - avoid peak currents from starting air compressor motor.

More energy efficient - save 30% of the energy used by a typical fixed speed compressor.

Precise electrical control - motor speeds can be slowed down, brought to a halt or revved up.

System leaks minimised - lower system pressure reduces the risk of leaks.

Could I benefit from a Variable Speed Drive Compressor?

Many air compressor installations will benefit from the efficiency variable speed drive technology provides. Whether you are in the food and beverage industry, automotive, medical industry or even manufacturing, there will be times when your demand for compressed air will vary.

A combination of both variable and fixed speed compressors is thought to be the most cost-effective and advantageous set-up, resulting in the most energy saved and demands met.

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