BRE Burn Hall: 3x 160kW Extraction Fan Control
This project involved the design, supply and installation of a variable speed drive control system for three extraction fans at BRE Burn Hall. The new system replaced the existing star-delta starter arrangement, providing more precise fan speed control while significantly reducing energy consumption and maintenance costs.
Project Overview
BRE operates the largest burn hall in Europe at its site in Watford, where flammability testing is carried out on domestic, commercial and industrial products. The burn hall required an extraction system capable of safely removing fumes generated during testing.
Motor Control Warehouse worked with BRE to replace the existing star-delta starter system controlling three extraction fans with a fully automated variable speed drive control system.
The Challenge
BRE’s existing extraction system used three 185kW two-speed AC induction motors controlled by star-delta starters. The extraction fans were operated at full speed, with airflow regulated using three iris air flow valves.
While this provided the required airflow control, restricting the airflow using the valves did not reduce the energy required to operate the fan motors. This resulted in significant energy being wasted and created an opportunity for BRE to improve the efficiency of the extraction system.
BRE approached Motor Control Warehouse to develop a more energy-efficient method of controlling the extraction fans, while maintaining reliable and effective fume extraction from the burn hall.
The Solution
Motor Control Warehouse worked in conjunction with BRE to design, build, install and commission a fully automated variable speed drive (VSD) control system for the three extraction fans.
The new system uses three Invertek Optidrive HVAC 160kW, IP55 AC drives, housed within purpose-built, glass fibre weather-resistant enclosures. The existing two-speed motors were adapted for inverter control and fitted with specially designed output inductors between the drives and motors to reduce the dV/dt of the switching edges experienced by the motors.
The new VSD system was integrated with BRE’s existing automated extraction control system, allowing the airflow to be controlled more precisely through fan speed rather than relying on the iris valves to restrict airflow.
With the iris valves fully open, the extraction fans can now operate at the speed required for the application rather than continuously running at full speed. This provides a more efficient method of controlling airflow while maintaining the required extraction performance.
Key Features
- Three Invertek Optidrive HVAC 160kW, IP55 AC drives
- Fully automated variable speed drive (VSD) control
- Purpose-built glass fibre weather-resistant enclosures
- Existing two-speed motors adapted for inverter control
- Specially designed output inductors to reduce dV/dt at the motors
- Integration with BRE’s existing automated extraction control system
- Precise airflow control through fan speed
- Reduced fan operating speeds and energy consumption
- System designed, built, installed and commissioned by Motor Control Warehouse
Outcome
The new variable speed drive system allows the extraction fans to operate at lower speeds while maintaining the required airflow, significantly reducing energy consumption compared with the previous system.
The improved automated control also reduces maintenance requirements by allowing the fans to run for less time and eliminating the need for manual adjustment of the iris air flow valves. Reduced fan speeds also help to lower acoustic noise and extend the operating life of the equipment.
The energy savings and reduced maintenance requirements provide BRE with a more efficient and cost-effective extraction system, with the potential for a short payback period on the investment.
Kes Beech, Technical Manager at Invertek Drives, confirmed: “Full payback on installation of Optidrive HVAC is usually achieved within 12 months based on current energy costs in this type of application.”