Industrial Energy Saving Retrofit
Steel Plant Fan and Pump Energy Saving Retrofit
Medium voltage VFD retrofit on induced draft fans and circulating water pumps, with throttling losses removed and closed loop pressure control added.
Original condition
The problem on site
Fans and pumps were sized for maximum campaign and then throttled by dampers and valves for most of the year. Energy was billed per tonne of product with no sub-metering, so nobody could say where the loss was.
Engineering approach
What we designed and built
- 01Installed temporary metering on each drive to record load profile, operating hours and throttling position over four weeks.
- 02Compared the actual operating point with the pump and fan curves to identify oversized equipment and recirculation losses.
- 03Selected medium voltage drives with bypass cabinets so production can continue if a drive trips.
- 04Added closed loop control on furnace pressure and cooling water return temperature instead of manual damper setting.
- 05Repeated the metering after commissioning and issued a verification report with the calculation method.
Measured results
Before and after commissioning
Values recorded on this project under its own operating condition. Results at another plant depend on fuel, material, load profile and the local standard in force.
| Item | Before | After |
|---|---|---|
| Retrofit scope | Damper and valve throttling control | 12 drives, 15 kW to 1,250 kW |
| Fan operating point | Far from best efficiency point | Speed controlled to match load |
| Measured power saving | Baseline metering installed | Saving verified by before and after metering |
| Start-up current | Direct on line inrush | Soft start with reduced mechanical stress |
Outcome
How the system runs now
Twelve drives were commissioned across induced draft fans, circulating water pumps and a compressor. Power consumption at the same production rate dropped in line with the reduced speed operation, verified by the before and after metering protocol. The exact saving rate depends on the load profile of each machine.
Site records
Fabrication, erection and commissioning
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