The energy question
Fixed-speed machines are efficient at full load and wasteful when running unloaded. Variable-speed machines follow demand but have their own efficiency range. The aim is to choose how each machine runs so that total power is as low as the demand allows.
What to analyse
Establish:
- The demand profile across the day and week
- The efficiency of each machine at different loads
- The pressure band and control settings
- The usable turndown of variable-speed machines
Implementation
Rank the machines, set pressure bands that avoid overlap, and coordinate with a sequencer or master control where needed. Check how the system behaves when a machine is out of service.
Verify the benefit
Measure power before and after under comparable demand. We do not assume a percentage saving.
Starting data
To start, it helps to have:
- Compressor make, model, rated power and controls
- Operating pressure settings and the lowest pressure the processes need
- Operating hours and shift pattern
- Any existing power, flow or pressure records
Frequently asked questions
Which is better: VSD or base and trim?
It depends on the demand pattern and the machines. We compare the options using your data.
Will a VSD fix my energy cost?
Only where demand varies and the rest of the system is in order. Measure first.
Can I improve control without new machines?
Often yes. Better settings and coordination can reduce unloaded running.
Field guide
Base, trim and VSD: the energy view
The control arrangement of a multi-compressor station often decides more of the energy bill than the efficiency of any single machine. The goal is simple: as few machines as possible running unloaded, and only one machine part-loaded.
What to look at
| Measurement | Good sign | Warning sign |
|---|---|---|
| Unloaded hours on fixed machines | Low share of total hours | High share: machine is trimming |
| VSD speed trend | Mostly mid-range | Always at maximum, or cycling at minimum |
| Number of machines running at night | Matches night demand | Same as day shift |
| Pressure band | Narrow and stable | Wide swings or staggered settings |
Improvements often come from settings and sequencing rather than new equipment. Where a new machine is justified, a correctly sized VSD as the single trim machine is usually the first candidate. See base and trim control.
What to send for a quotation
- Compressor make, model and rated power of each machine.
- Electricity tariff and annual running hours.
- Typical pressure at the compressor and at the furthest user.
- Any measurements you already have (power, flow, loaded hours).
Send it through find my part or the spare parts enquiry, or call +91 99590 60718 or +91 92468 88812.