EcolibriumTHE OFFICIAL JOURNAL OF AIRAH OCTOBER 2015 · VOLUME 14.9

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When ex-convict Isaac Nichols established Australia’s first post office from his George Street home in Sydney on April 25, 1809, it’s doubtful he would have envisaged the legacy he would leave behind.

Some 206 years later, Australia Post is the nation’s oldest, continually operating organisation and has grown to establish one of the largest property portfolios in Australia.

From post offices, mail processing centres and warehouses, to offices and call centres, its buildings are as diverse as the services it provides. But they are

also responsible for 68 per cent of the company’s greenhouse gas emissions.

However, Australia Post is committed to initiatives that reduce the environmental footprint of its operations, having implemented energy-efficiency measures at more than 200 of its sites. This has seen the business reduce its emissions by 14 per cent compared to 2000 levels. Its overarching target is a 25 per cent carbon reduction target by 2020.

This same commitment has extended to its NSW headquarters at 219 Cleveland Street, Surry Hills.

ROADMAP TO SUCCESSConstructed in 1989 on the site of the original Redfern Mailing Ground to the south of Sydney’s CBD, the building had a net lettable area (NLA) of approximately 25,850 sq m across five levels of commercial space. The ground-floor level combines office space, lobby and gym.

As Australia Post’s requirement for space in the building diminished over time, areas of the office were tenanted out.

Then, following a broad organisational review in 2012, a decision was made to implement a major refurbishment to prepare the building for sale.

NDY was appointed to spearhead the project’s ESD ambitions, as well as provide mechanical, electrical, hydraulic, communication, fire engineering, and fire protection services advice. Its role also extended to energy modelling, which was used to identify options to improve the building’s existing 2 star NABERS rating to 5 stars.

F E A T U R E

Special deliveryReflecting Australia Post’s commitment to reduce the environmental footprint of its operations, a refurbishment  of its New South Wales headquarters in Surry Hills has delivered an A-grade quality commercial office space.  It has also achieved a rare Green Star triple feat.  Sean McGowan reports.

AWARD FINALIST

TherefurbishmentofStarTrackHouseisafinalist

inthecomingAIRAHAwards,withthewinnertobe

announcedatagaladinneronNovember26inSydney.

AIRAH AWARDS 2015 FINALIST

F E A T U R E

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According to NDY director, Campbell Williams M.AIRAH, the original brief was to increase the NLA of the building to 29,124 sq m and achieve a minimum A-grade finish and specification in accordance with the Property Council of Australia’s quality grade matrix for existing buildings.

In addition, the building was to be upgraded and modified to current BCA 2013 compliance.

As well as engineering services, NDY also provided Green Star consultancy to shepherd the project to achieving its Green Star targets

of 5 star Green Star Design and As Built (v3) ratings, as well as a 5 star Green Star Interiors (v1.1) rating.

A further commitment agreement was also undertaken to achieve a NABERS BB Energy 5 star rating, including an independent design review.

A total of 1,048 solar panels have been installed on the rooftop of the Australia Post building to produce 371.5MWh of electricity per annum.

F E A T U R E

This was all to be achieved without disrupting the business-as-usual operations of Australia Post, and so as not to jeopardise the rights of existing

tenants to the “quiet enjoyment” of their premises. During the Australia Post fitout, both the targeted NABERS and Green Star ratings were also to be protected.

To meet these objectives, NDY developed a “road map”, which included potential upgrade options and a list of sustainability opportunities with cost estimates.

“The road map enabled the client to develop a business case for improving the building,” says Williams. “It defined the scope for the project team and provided a consistent goal for the project team to achieve.”

The performance of the existing building was determined through condition auditing and simulation modelling, with a number of initiatives then developed and prioritised by the design team.

“These included the upgrade of existing mechanical plant, installation of a solar PV array, and utilisation of simple, intelligent sustainable practices and technologies that significantly reduce the environmental impact,” Williams says.

Overarching initiatives included a reduction in greenhouse gas emissions

An aerial view of the building, which went from 2 star NABERS to 5 stars.

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F E A T U R E

and energy consumption, and a reduction in the contamination of water, air and soil.

MIDTERM UPGRADEA number of end-of-life upgrades had been made to the building’s mechanical services over the years, including a chiller and cooling tower replacement. However, the building was generally served by systems typical of the era in which it was built.

To bring the property up to the standards expected by today’s tenants, these were identified as being over 20 years old and in need of a midterm upgrade.

The central mechanical plant comprised of cooling towers, chillers, boilers and associated pumps; the building’s air-handling system was made up of six main air-handling units (AHUs) located in a rooftop plantroom.

Three constant-volume AHUs served the building façade, while the interior zones were served by three variable-air-volume (VAV) AHUs. Supply air was delivered to the occupied space via ceiling-mounted air and light diffusers.

“The variable-volume system included fan-assisted variable-air-volume boxes serving the centre zone,” says NDY senior mechanical engineer, Zoia Geller. “And the perimeter zone was served by variable-air-volume boxes supplemented by the constant-volume systems.

“The building is provided with a smoke-spill system utilising dedicated smoke-spill fans and the existing return-air shafts.”

The building management system (BMS) was a combination of the original electronic and pneumatic controllers installed and commissioned in 1990.

Although the existing central plant and air-handling system offered sufficient capacity, its operation was not energy efficient due to these old controls, and poor zoning and air distribution. Major air distribution systems required tuning, and a high air-leakage rate was also present.

However, NDY’s base-building energy model was able to demonstrate that the project could be improved from its 2 star NABERS Energy rating to 5 stars without a major redesign of the building’s mechanical, electrical, fire and hydraulic systems.

“The final report included a prioritised list of projects, with approximate costs and star improvement steps for each, bringing the model to a 5 star rating with a contingency buffer,” says Geller.

TRIM AND RESPONDNDY’s recommendations to improve the energy performance of the Australia Post building included a complete overhaul of energy sub-metering, BMS, and controls.

A “trim and respond” control strategy resets the control set-points using zone-voting requests for static pressure, cooling and heating demands.

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F E A T U R E

It also installed new high-efficiency chillers and variable-speed drives (VSD) to all electric motors.

All systems were recommissioned, and economy cycle changed to enthalpy control, with outside air dampers replaced. A number of variable-air-volume strategies were implemented. The internal design comfort conditions were also broadened, and the constant-volume skin system was optimised.

Common area lighting was also upgraded, and controls added.

The early engagement of Engineering Commissioning Services (ECS) as independent commissioning agent (ICA) also benefitted the project by identifying commissioning issues in the early design stages.

And it also gave the ICA the opportunity to work closely with the project team throughout all stages of the project.

“Working with and guiding the main contractor and sub-contractor ensured that the works were commissioned to achieve the design outcomes and meet the client’s expectations,” says ECS senior commissioning manager, Trevor Delaney.

As part of an energy audit and functional assessment of the BMS, the review identified that the existing system could be replaced in stages to improve occupied space conditions and reduce energy consumption without disruption to the occupied building.

As well as improving controls functionality through improved programmability and controls schemes to allow for more energy-efficient operation, the BMS replacement also provided resilience. The existing system had reached the end of its economic life.

In an innovative approach, NDY designed a “zone voting” control strategy, with dynamic demand response (DDR) to maximise the energy efficiency of the building in operation.

“It is one of the most advanced controls systems in the world,” says Geller.

Only the second building to feature the control strategy – the first being NDY’s own North Sydney offices – it formed a key part of achieving the 5 star NABERS Energy rating by optimising energy while maintaining occupant comfort.

The “trim and respond” control strategy resets the control set-points using zone-voting requests for static pressure, cooling and heating demands, incrementally resetting the associated plant set-points over a time period determined by the amount of requests received. The more requests, the quicker the response.

“Buildings are dynamic, with constant changes in ambient conditions and occupancy levels,” says Williams.

“The logic behind ‘trim and respond’ is that it makes sense to track the behaviour of the building and provide just enough air conditioning to meet the zone requests – always trying to trim back when the requests are satisfied.”

With this strategy in place, fan efficiency is now being maximised, and the tuning process streamlined.

“The building is exceeding all energy targets consistently,” Williams says.

A FINAL PUSHThe building services upgrades and building fabric improvements, including new double glazing, were able to improve the base building’s NABERS energy rating from 2 to 4.5 stars. Yet it was the addition of a large solar photovoltaic array that proved crucial in achieving the 5 star target.

According to Williams, it was found that even with the lighting upgrades, the base- building areas would still consume too much energy to obtain a 5 star rating.

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The 283kW PV array was the last resource on the proposed measures list due to its high capital cost and lower payback when compared to other energy-efficiency measures. But it was found to be necessary to offset the base-building energy consumptions and to achieve the desired rating.

“NDY established the required PV system size to achieve a 5 star NABERS rating,”

Williams says. “And this formed the basis of the specification and contractor’s brief.”

A total of 1,048 solar panels have been installed on the rooftop of the Australia Post building to produce 371.5MWh of electricity per annum – enough to reduce the base- building electrical load by 25 per cent at peak times.

“To put this in context, an average Australian house might install a 2.5 to 3kWp photovoltaic array,” he says. “The Australia Post system is about 100 times the size.”

Williams says PV systems are an increasingly common feature of new buildings and major refurbishments – due in large part to increasing efficiency, reliability, and most importantly, declining costs.

“Prices for photovoltaic systems have come down dramatically in recent years,” Williams says. “The current cost of large (10kWp) solar PV systems is around $1.64 per Watt. Compare this to prices in 2010 that were about $6 per Watt … three times as expensive as they are now.”

Williams says Australia Post’s decision to install such a large PV array is indicative of the company’s commitment to

energy efficiency, which will have flow-on benefits to the broader community.

“When a major organisation like Australia Post commits to improving their energy efficiency and makes such a big investment in renewable energy generation,” he says. “It sends a strong signal to the broader business community that implementing the right sustainability initiatives makes good business sense.”

A VALUABLE LEGACYSince being renamed StarTrack House by Australia Post, the refurbishment project has been transformed from a dated and underutilised office into a modern and efficient space.

The building’s capital value has also been substantially improved.

And in doing so, it has become the first office building refurbishment in NSW to achieve the rare feat of receiving three 5 star Green Star accreditations for Design, As Built (v3) and Interiors (v1.1).

“As an industry we need to move away from the ‘knock-down and rebuild’ mentality, and focus on how we can more effectively use the resources already invested in legacy buildings,” says Williams.

“Updating a legacy building to achieve best-practice sustainability and construction-code outcomes demonstrates world’s-best-practice refurbishment.” ❚

REPOSITION ASSETSCampbell Williams M.AIRAH, director at NDY, shares his lessons  from this project.

“Poorlyperforming,existingbuildingassetscanbetransformedintoleadingexamplesofindustrybestpracticeforenergyreduction,sustainabilityandoccupantcomfort,”says,NDY’sCampbellWilliams,M.AIRAH.

“Clientsneedtobeconsultedandguidedtoenablethemtorealisetheiraspirationsforbothsustainabilityandfinancialrewardwhenrepositioningtheirphysicalassets.”

The personnel

■    Architects:   CARRDesignGroup

■    Building services engineer:  NDY

■    Client:  AustraliaPost

■    Contractor:  Buildcorp

■    ESD:  NDY

■    Independent  commissioning agent:  ECS

■    Mechanical Services Contractor:  TripleM

HVAC equipment

■    Air dampers:   CelmecInternational

■    BMS:  Optergy

■    Chillers:  Powerpax

■    Diffusers:  Airfoil

■    Fans:   PacificHVAC(FansDirect)

■    Grilles:  Airfoil

■    Heat exchangers:   CoilsAustralia

■    Pumps:  KSBAjax

■    PV array:  Yingli/AuroraSolar

■    VSDs:  ABB

STARTRACK HOUSE, SURRY HILLS

AT A GLANCE

The building earned 5 star Green Star ratings for Design, As Built (v3), and Interiors (v1.1).