Variable Speed Compressors for Improved Energy Efficiency

Summary

This video script explains the efficient operation of a variable-speed and fixed-speed compressor system. It covers how these compressors work together to meet varying air demands, adjusting speed and load as necessary. The variable-speed compressor optimizes energy usage by adjusting to demand, while the fixed-speed compressor supports when demand is high. Key moments include the compressors' response to system pressure, start-up procedures, and adjustments during production cycles. The script provides a comprehensive guide to sequencing compressors for efficient operation in a dynamic environment.

Takeaways

• 😀 Variable-speed and fixed-speed compressors can operate efficiently together without requiring a sequencer if set up properly.
• 😀 The fixed-speed machine should have on-load/off-load controls with a timed shut down to minimize energy consumption.
• 😀 All pressures discussed are gauge pressures in this presentation.
• 😀 When both compressors are turned on in the morning, they work together to fill the system header, with no air demand initially.
• 😀 As the header pressure rises above 6 bar, the fixed-speed machine continues to run at full load while the variable-speed machine adjusts to maintain pressure.
• 😀 Once the header pressure reaches 6.9 bar, the fixed-speed machine unloads, and the variable-speed machine enters a blowdown cycle before shutting down.
• 😀 At 8 a.m., when production starts, the variable-speed machine adjusts its speed to meet the demand and maintain stable header pressure.
• 😀 The variable-speed machine can handle air demands up to 13.6 cubic meters per minute, but struggles with higher demands, triggering the fixed-speed machine to kick in.
• 😀 As air demand fluctuates throughout the day, both compressors may operate in tandem, with the fixed-speed machine fully loaded and the variable-speed machine adjusting its speed.
• 😀 During periods of lower production, the variable-speed machine may run alone, while the fixed-speed machine stays off or unloads.
• 😀 The system is designed to ensure energy efficiency by dynamically adjusting the compressor speeds to meet varying air demands throughout the day.

Q & A

What is the primary purpose of using a variable-speed compressor alongside a fixed-speed compressor?

The main purpose is to operate the compressors efficiently together, optimizing energy usage by adjusting the compressor speeds according to the air demand in the system.

What is the role of the compressor sequencer in this setup?

In this specific setup, a compressor sequencer is not required because the system can function efficiently without one, with both compressors operating based on pressure and demand.

What is the significance of having on-load/off-load controls for the fixed-speed compressor?

On-load/off-load controls are important for the fixed-speed compressor as they minimize energy consumption by unloading the compressor when the system does not require its full capacity.

How does the system react when there is no air demand and both compressors are running?

When there is no air demand, both compressors load fully to fill the system header, and the system pressure rises. The fixed-speed compressor remains at full load, while the variable-speed compressor adjusts to maintain pressure.

At what pressure does the variable-speed compressor enter a blowdown cycle?

The variable-speed compressor enters a blowdown cycle when the system pressure reaches 7 bar, at which point it shuts down after 20 seconds.

How does the variable-speed compressor handle low air demand during the morning start?

During low air demand in the morning (4.2 cubic meters per minute), the variable-speed compressor adjusts its speed to match the demand, maintaining stable header pressure.

What happens when the air demand exceeds the capacity of the variable-speed compressor?

When the air demand exceeds 13.6 cubic meters per minute, the fixed-speed compressor starts up to assist, and both compressors work together to meet the demand.

What is the relationship between air demand and compressor operation throughout the day?

As air demand fluctuates throughout the day, the variable-speed compressor adjusts its speed to meet varying needs. The fixed-speed compressor only activates when the demand is high enough to require its full capacity.

What happens to the compressors during lunchtime when air demand decreases?

During lunchtime, when air demand drops to 6 cubic meters per minute, the variable-speed compressor slows down, while the fixed-speed compressor continues to operate at its full capacity until the system pressure rises and it unloads.

How do the compressors maintain stable system pressure despite varying air demand?

The compressors adjust their operation based on system pressure. The variable-speed compressor modulates its speed to maintain stable pressure, while the fixed-speed compressor either remains fully loaded or off, depending on the demand.