The State Library of Victoria in Melbourne, Australia’s second largest city, is a reference and research library that attracts more than one million visitors a year. Founded in 1854, the library's collection of two million books, as well as reading rooms, galleries, exhibition spaces, conference centre and coffee shop occupies two hectares, an entire city block.
An energy appraisal of this space found significant energy savings were possible by replacing the existing flow control in the HVAC system (heating, ventilation and air conditioning), which used throttling valves, with ABB variable speed drives.
The library has four water-cooled chillers with eight motors ranging from 15 to 55 kilowatts (kW); five cooling tower fans with one 11 kW motor each; and two gas-fired heating boilers with one 22 kW and one 30 kW motor on the hot water circulation pumps. By installing 15 ABB standard drives for HVAC, energy savings of between 30 and 60 have been achieved across the various applications.
This is equivalent to 1,800 megawatt-hours (MWh) a year, worth $155,000 annually in reduced energy costs. The payback time, including reduced maintenance costs: around 13 months.
Besides reducing energy consumption, the drives have improved chiller compressor efficiency and cooling tower fan control. They have also reduced noise pollution from the cooling tower fans, eliminating a disturbance to library visitors and nearby residences.
Maintenance has also been reduced as the constant stop-start control of the fans has been replaced by the soft start of the drives, which reduces the wear on motor bearings, fan bearings and fan belts.
Working with energy efficiency can be a challenge in an old building,” says Mike Brown, facilities manager at the library. “No matter how hard we try to raise efficiency, it will never match a modern building. The library is 150 years old and heritage-listed. Its large halls with high ceilings make it difficult to air-condition. Some of the walls are a meter thick, which makes it hard to achieve the desired temperature.
“Under these conditions using AC drives is a useful way to save energy where we can. It also helps us control conditions accurately – the temperature needs to be controlled to 22 degrees and humidity to 50 to protect manuscripts, paintings and the two million books.”
The system has exceeded expectations,” concludes Brown. “It has been very reliable and produced massive savings in energy and maintenance that will be reaped in the coming years.