ABB variable-speed drives achieve 6-month payback
A semiconductor manufacturer in Plymouth is saving over £30 000 a year since installing six 37 kW ABB HVAC drives on its three cooling towers. The £15 000 installation for X-FAB, one of the largest semiconductor manufacturers in the UK, is set to give a payback in only six months — with an annual saving of £31 400. The drives were installed by local ABB HVAC partner Drive Control. A clean and vibration-free environment is a top priority in semiconductor manufacture, and the company uses large quantities of air and water to maintain cleanliness. The three cooling towers produce chilled water for manufacturing. The six fans in the three cooling towers were originally star-delta operated to come on or go off one at a time as demand varies. Fans could be switched on and off as often as every 10 minutes and had significant starting currents. Whenever an odd number of fans were connected, air from the last fan would blow out through one of the other fans. With the ABB drives, two fans start on the first towers at 20 Hz when the BMS indicates that cooling is needed. If more cooling is required, the next two fans start at 20 Hz, followed by the final two. For further cooling, all six fans operate at the same speed — up to 50 Hz. Maintenance costs have also been reduced, as the drive belts used to break at least once a month. Ted Judge, senior facilities engineer at X-FAB, says, ‘I hadn’t used drives much before Drive Control came along to give me a demonstration. However, I now see that using variable-speed drives is the most effective way for us to save energy. I have a 10-year plan for how to reduce energy use at the site, and it will mainly be achieved with drives. 70% of electricity at the plant is used by motors, so there is vast potential for using drives.’
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