Car-park ventilation system gets ABB drives make-over
The NCP car park in Drury Lane, Covent Garden, has been refurbished with variable-speed drives (VSDs) from ABB to give better control of the ventilation system and reduce energy use. NCP wanted to modernise the ventilation of this 330-space car park to meet current demands for energy efficiency and achieve energy savings.
George Murphy, building-services engineer — south, for NCP explains, ‘The car park is used at predictable times, with business from commuters during the day and theatre goers during the evening. We wanted a system which would proportionally control the ventilation dynamics in response to the actual vehicle movements in the car park while maintaining adequate statutory environments conditions. This step change has also resulted in reduced wear and tear on the ventilation system.
NCP asked ABB HVAC partner Drive Control to look at how the system could be improved. The company recommended using four VSDs — two 37 kW drives for the fume-extract fans and two 22 kW drives for the supply fans. To simplify the project, much of the original cabling and some original switches were retained.
A carbon-monoxide (CO) sensor next to each VSD sets the speed of the fan. Maximum speed is 50 Hz at 100 ppm of CO and 20 Hz when it is below 50 ppm.
The supply fans are driven by two old 19 kW class E motors, requiring the installation of output-side filters to the VSDs to reduce the possibility of damaging the motor windings.
The project was part of a rolling programme that has seen Drive Control refurbish 25 NCP car parks so far, with more planned for the near future.