Norman Disney & Young (NDY) has won a sustainability award for taking a building first constructed in 1982 to a 5 Star NABERS energy rating.
The retrofit project, undertaken on a 30-year-old office building at 215 Adelaide Street in Brisbane, won the Thinc Award for Best Sustainable Development (Existing Buildings) at the 2013 Property Council of Australia awards.
The building was among 107 finalists across 16 categories nationwide.
While most 4.5 or 5 Star ratings in new buildings are achieved with the use of trigeneration, this project had to rely on refurbishing and rebuilding.
This made technical and contract innovation critical.
For example, chillers were pre-ordered to ensure timely delivery and selection of the optimum combination of capital cost, reliability and energy efficiency.
NDY called tenders from select chiller manufacturers, requiring both price and detailed operational information.
NDY then put operational data into its energy model to precisely calculate the relative cost/value for each chiller plant option.
The consultancy recommended a combination of new technology Carrier 23XRV tri-roto variable speed screw base load chillers with a small Powerpax magnetic bearing unit for low load operation.
When it came to speed fan modulation, existing constant speed multizone AHU with VAV was retained with new motors, variable speed drive and control routines.
The use of a multizone unit with VAV presented significant controls challenges, especially working within the limitations of the existing VAV box controllers.
NDY undertook detailed fine tuning over two years to get the AHU controls operating in an optimal manner.
One of the most significant risks to the project was the chilled water thermal energy exclusion under NABERS.
To address this, NDY specified extensive chilled water energy metering within existing pipework along with additional smart metering of power supplies to the central chilled water plant.
The base building light fittings were upgraded to electronic ballast, single tube high output T8s with Y5 diffusers, which more than halved electricity consumption.
New modulating outside air dampers complete with a C02 sensor system to ensure outside air rates matched building occupation were introduced. Moreover, indoor environmental quality is routinely tested to achieve air quality benchmarks.
NDY conducted acoustic testing to ensure there were no problems.
Variable speed drives were added to on-floor supply and relief air fans to reduce both energy and noise.
NDY director Andrew Gentner says the company’s environmental team had been intimately involved with the project for over five years through project inception, design, construction and finally fine-tuning.
Facilities manager Jones Lang Lasalle says the new air conditioning services, including chillers, pumps, and cooling towers, had reduced the base building expenditure and outgoings significantly.