The recent multi-million-dollar upgrade of one of Brisbane’s largest buildings, Riverside Centre, which is owned and operated by The GPT Group, has set a new benchmark for an innovative HVAC refurbishment.
Compact EC plug fans were used to replace large and inefficient backward curved double-width double-inlet (DWDI) fans.
The upgrade of the 30- year-old building aimed to elevate the Riverside Centre to a 5.5 star NABERS energy rating and has also delivered in maintaining its status as one of Brisbane’s premium, iconic office towers.
The project is a strong example of successful collaboration between the four main parties involved in a building’s HVAC upgrade – building manager, consultant, contractor and supplier.
Constructed in 1986, the 40-storey Riverside Centre was hailed as ‘Brisbane’s first intelligent building’, an approach Brett Saunders, CEO at Hiflow, pursues in his own work.
‘When I saw the project come through I jumped at it, this is what I’ve been waiting for,” he said.
After 30 years, the original DWDI fans were approaching their end of life.
Andrew Prentice, mechanical engineer at Interior Engineering and consultant on the project, said the fans displayed the usual issues of bearing failure, bearing lubrication issues, belt and pulley wear, as well as some signs of pitting corrosion on the fan wheels.
Riverside operations manager, Clint Francis, said other drives for the HVAC upgrade were increased energy efficiency and customer comfort.
He said logistical challenges also had to be considered as the building’s location in Brisbane’s CBD made refurbishment of the existing, large fans difficult.
“From the sourcing of new components or entirely new fans, to the delivery of these into small areas that are not easily accessible, it seemed practical and feasible to replace the existing fans in favour of EC plug fan technology,” Francis said.
When the original design for the HVAC upgrade, consisting of the replacement of six air handling units, was put to tender, it specified fewer and larger EC plug fans.
But after reviewing the project, Thomas Heine, market manager at ebm-papst, put forward another option and that was to select a smaller individual fan size (500mm instead of 630mm).
This was due to logistics considerations as well as a reduction of actual available space because of the upgrade and enlargement of the coils.
According to Hiflow's Saunders, the aim was to minimise size while gaining efficiency.
“The project led to a breakthrough in installation, handling, efficiency and serviceability of the AHUs,” Saunders said.
Up to 10 x 500mm ebm-papst EC plug fans replaced one large DWDI fan. The plug fans are aligned in a five-by-two grid and mounted off the floor, removing the need to add floor mounts.
Hiflow's Josh Mitchell, project manager for the upgrade, said the new EC fans are fully integrated into the building’s BMS via high level interface and part of the zone pressurisation in fire mode.
Mitchell said he approached the project with serviceability in mind.
“I know that with a smaller fan a technician and an apprentice can remove and replace it. Once you start moving into the larger, heavier fans, the client gets more downtime, because you can’t just send two people in to lift it,” he said.
This view was shared by the consultant Andrew Prentice. “Typically, the smaller and lighter the equipment, the easier it is to install,” he said. “Using a crane to get equipment into a building in Brisbane’s CBD is just not realistic.
“Instead, the fans were simply delivered on pallet jacks via the goods lift.”
Financial feasibility
While installation and handling are important factors at the time of refurbishment, financial feasibility was also an important consideration.
CBD-based office buildings are typically premium properties due to their central location.
Building owners and operators, such as The GPT Group, who have owned and operated Riverside since the building’s inception, need to ensure their portfolio continually delivers value for tenants, with customer satisfaction at the forefront of their operations.
Riverside Centre's operations manager, Clint Francis, said whenever the Group undertake an upgrade the brief to consultants is usually 'best in class' which is why they chose ebm-papst EC plug fans.
While the savings couldn't be measured directly, Francis said anecdotal evidence suggests a reduction in fan power use by 15%.
With the HVAC system accounting for about 60% of the building’s energy consumption, any reduction in fan energy use can make a big difference to the bottom line for each tenant.
Air-movement is the heart of the air-conditioning system which is why continuity of service is an important consideration when selecting suppliers, according to Interior Engineering consultant, Andrew Prentice.
“A company that offers continued selection and technical advice in their local market should be given greater recognition because service and backup for ventilation equipment is just as important as it is for refrigeration equipment and ebm-papst certainly delivers in this regard,” he said.
As the largest supplier of EC plug fans into the Australian HVAC industry, ebm-papst delivered 4,450 units in 2015 alone and is in addition to the products installed in imported equipment.
Training sessions on EC technology were held to ensure tight timelines were met. In the case of the Riverside upgrade, all HVAC units had to be back up and running by Monday morning, in time for office workers to return to their desks.