Air movement systems make up a large part of a building's power consumption.
Whilst new air movement technologies and equipment are implemented in new commercial and domestic builds, there is a range of aging end-of-life products installed in many existing buildings. ebm-papst’s EC Upgrades team has been identifying where upgrades can be performed to improve air movement systems without re-inventing the wheel, this is where energy reductions benefit the bottom line the most.
Firstly, there are challenges end-of-life air movement systems face. The air conditioning system in Brisbane’s Birkdale Shopping Centre was nearing end of life.
The existing air conditioning system was old and its performance was deteriorating, struggling to perform the cooling capacity it was previously designed to achieve.
There were two options in combating this problem; either replace the entire air handling unit system with a new one, or upgrade the air handling units with more powerful and efficient fans.
Local air conditioning contractor Marty Page of Advanced AirConditioning realized that replacing the old, single fan AHU system would be difficult and costly with so little space.
Associated with the age of the equipment were other challenges such as the timely availability of spare parts and increased maintenance schedules.
Since the existing air handling units could not be removed and new air handling units could not be installed given the existing plant room layout, Page looked into an upgrade of the existing systems to include backward curved plug fans with EC technology.
Fan upgrade
At the shopping centre, three different air handling units with belt-driven forward curved centrifugal fans were replaced with seven EC backward curved plug fans from ebm-papst.
The main challenge here was the ongoing operation of the shopping centre:
“Our task was to upgrade the fans while keeping the temperature in the shopping centre constant at the same time,” Page said.
“With 2,400 square metres of retail space, we were unable to provide sufficient temporary cooling to switch off all systems at the same time. So the new fan grid had to be put into operation and run before the next fan to be replaced could be switched off. This was the only way to complete the retrofit.”
By using EC backward curved plug fans, Page was able to complete the upgrade with the space restrictions that were in place. Existing doorways and access points were used to move the new products and materials into position.
Old components that were too large to move through these points were dismantled and removed. Additional maintenance costs are now a thing of the past, as no belts, belt pulleys or bearings need to be serviced or replaced.
In the rare case that one fan fails, the speed of the other fans can be increased to compensate for the failure. In addition, the EC fans can withstand a higher static pressure.
Simple controls and energy savings. With the new fans, the same air volume flows with lower power consumption. The change in installation from forward curved to backward curved fans has allowed for improved and more efficient airflow in the air conditioning system.
Instead of running at a fixed speed, the speed of the fans can now be regulated flexibly thanks to the EC fans and a control update which adjusts the fan speed depending on cooling demand. This results in additional savings, as the fans can run as low as 50% of design air flow once cooling or heating demands are met.
New installation
A measurement was performed where power consumption of the new installation was compared against the original installation.
All three air handling units were found to have reduced their power consumption by at least 50 per cent.
A unit which had three EC backward curved plug fans instead of two achieved a peak value of almost 70 per cent lower power consumption with 13 per cent higher air flow.
In the end, the upgrade work has modernised the air conditioning system at Birkdale Shopping Centre and made it a more robust, reliable and efficient design for many years to come.