Norman conquest - AIRAH ay13/05-13... · 40 eC olibriu M • MAY 2013 COVER FEATURE Norman conquest As the first refurbished building to achieve 5 star certification under all three

eColi br i u M • MAY 201340

C O V E R F E A T U R E

Norman conquestAs the first refurbished building to achieve 5 star certification under all three Green Star office rating tools, Norman Disney & Young’s West Melbourne headquarters has been quite the win in terms of showcasing the firm’s commitment to sustainable design. As Sean McGowan writes, the brains behind the NDY building is a simple but effective controls strategy.

Other than the red-brick façade, there’s little that tells of the history of the modern building at 115 Batman Street, West Melbourne

Gone are the multi-paned windows, the street-front loading bay and the heavy entry door of the former run-of-the-mill factory built in the 1940s. They’ve been replaced with a high-performance façade of shaded, double-glazed windows and modern, canopied entry.

Once double-storey, the building now spans four levels. A basement car park, as well as the ground and first floors, are within the original façade. Two additional floors sit above.

In many ways the transformation of this building reflects the evolution slowly occurring at this once gritty end of Melbourne. Heavy industry has given way

to trendy apartment living, and businesses willing to forego a CBD location for more spacious, affordable accommodation on Melbourne’s city fringe.

When Norman Disney & Young (NDY) sought to relocate its entire Melbourne and corporate team, it saw the potential to practise what it preaches by showcasing sustainable refurbishment in a building that had otherwise remained unloved for years.

“This was definitely a key factor in the selection of this site,” says Cameron Forbes, an associate for NDY’s MPlus group, which specialises in improving existing buildings.

“There was a desire to move into a building of our own such that we could demonstrate our expertise in designing a high-quality and sustainable building. As a leading building services consultant, it

was important for us to show that we can walk the talk.”

Along with setting out to provide a quality working environment and showcase the firm’s building services, the brief placed particular emphasis on energy and water conservation.

“The site was effectively a blank canvas due to its state of extensive disrepair, and gave us the opportunity to really do what we wanted,” Forbes says, “within our budget constraints.”

old beCoMes neWAlthough NDY originally intended to retain much of the original building, including the slab, structural requirements of the refurbishment project determined that only the red-brick façade could be saved.

41MAY 2013 • eColi b r i u M

C O V E R F E A T U R E

The remainder of the building was completely gutted.

Because it faces north, and has little shading from surrounding buildings, the original 470mm thick double-brick façade was deemed to provide excellent insulation. It formed the starting point of the high-performing, energy-efficient design.

because the building size

or load could not justify

the cost of on-site power

generation, ndY’s design

focused instead on ensuring

that all installed features and

services were designed to

best-practice efficiency and

performance’Working with e+ architecture throughout the process, NDY’s design seamlessly integrates the old and new by using external cladding on the new upper two floors. This created a number of points of architectural interest where the original brickwork becomes more obvious.

This is perhaps best illustrated on the west façade where the pitch of the original roof can be seen.

The existing window openings were retained across the two lower floors, with double glazing set back, and external shading devices added on the north and west facades. This design provides effective sun shading, while allowing natural light to reach workstations.

Due to the daylight contribution, electric light levels were able to be minimised to 95 per cent of the net lettable area. Automated lighting zones were designed to be below 100 sq m across all of the tenancy area.

High-performance insulation was applied to the new, corrugated pitched roof, as well as the underside of the new ground-floor slab, and the new façade applied to the upper two floors.

“The high-performance façade, including high-performance insulation, has the benefit of not only minimising the energy consumption required to cool and heat the office space, but also reduces the capacity and associated capital cost of the air conditioning equipment installed,” Forbes says.

Because the building size or load could not justify the cost of on-site power generation, NDY’s design focused instead on ensuring that all installed features and services were designed to best-practice efficiency and performance.

PAssiVe Cooling designThe high-performance façade contributed to a heat load of less than 85W/sq m in the perimeter zones, so a passive cooling design was adopted.

Although alternatives such as variable air volume (VAV) and under-floor displacement were considered, passive chilled beams were ultimately selected due to their lower energy consumption profile and excellent indoor environment quality.

All services have been deliberately left exposed in the building to showcase the system.

“Water is a more effective heat-transfer medium than air, which therefore results in a more efficient means of transferring energy from the occupied spaces,” says Forbes.

“Chilled beams decrease the required amount of air to be delivered to the space, as we only need to deliver sufficient ventilation rates to meet the minimum outside-air requirements, not the large volumes required by traditional air conditioning methods.”

The project also benefited from the reduction in duct sizes and reduced requirement for supply air fans as a result

NDY’s headquarters features deliberately exposed services, showcasing the building’s systems.

eColi br i u M • MAY 201342

C O V E R F E A T U R E

of this selection. However, the impact of the top floor’s roof heat-load and higher occupancy (the main boardroom and other meeting rooms are located on this level) resulted in a VAV system being deemed more appropriate for this floor than chilled beams.

Forbes says that at the time of design there were limitations on the cooling capacity chilled beams could achieve.

“The top floor has increased cooling requirements due to the roof load, and increased occupancy,” he says. “Its total heat-load is greater than the lower floors, and for this reason a VAV system was deemed more suitable for this floor.

“It also gave us the opportunity to compare the two technologies in operation, something not many in the industry are able to do on a daily basis.”

Both systems are serviced by a high-efficiency, single-compressor, air-cooled chiller. The chilled-water loop is divided in two, with the primary loop connected to the building’s air-handling and fan-coil units. The secondary chilled water loop serves the chilled beams.

The chiller combines an adiabatic condenser that uses wetted pad heat rejection on warmer days to decrease

the temperature of the air onto the chiller’s condensing coils.

Along with reducing the chiller’s load and energy consumption, it improves reliability on high-ambient-temperature days, and minimises water consumption. It also eliminates the risks of Legionella that are associated with water-cooled chillers.

designing buildings services

is the core of our business, but

being able to design, deliver

and occupy the one building

has given us all valuable

insight into the challenges

that our clients face’“The performance of the chiller during the 40°C plus days that Melbourne experiences during our hot summers has never been an issue,” says Forbes.

Two, full-fresh-air air-handling units were installed to serve the lower levels of the building.

They supply twice the volume of fresh air as is required by standard, and temper the air with chilled and heating coils.

Additionally, they provide a key control measure of dehumidification in the space, ensuring that the dew-point temperature remains below the operating temperature of the chilled beams to ensure no condensation on the beams occurs.

The upper floor is serviced by two air-handling units with modulating outside and return-air dampers to enable economy cycle (free) cooling when the ambient conditions allow.

“This is a very simple yet effective means of decreasing the building’s energy consumption,” Forbes says.

A high-efficiency gas-fired boiler also supplies hot water to the main air-handling units, as well as to hydronic heating panels located around the perimeter of the building.

These panels are designed to overcome heat loss through the façade during the cooler months.

To further reduce the building’s energy consumption, all major pumps and air-handling fan units are equipped with variable speed drives. Domestic hot water is supplied by a solar heated system.

To aid in water conservation, a 15,000 litre water tank was installed below the basement concrete slab to store rain water

With the exception of the top floor, 115 Batman St is cooled by passive chilled beams.

43MAY 2013 • eColi b r i u M

C O V E R F E A T U R E

The top floor has increased cooling requirements due to the roof load.

eColi br i u M • MAY 201344

C O V E R F E A T U R E

NDY attempted to keep the control strategies as simple as possible.

45MAY 2013 • eColi b r i u M

C O V E R F E A T U R E

collected from the roof. This water is used for fire testing and toilet flushing.

High-efficiency, low-flow water fittings are also used throughout to achieve the designed daily water consumption of 7.28 litres per person.

under ControlCritical to the building achieving its 5 star Green Star ratings and its ongoing performance is the building’s management control system (BMCS).

Designed by NDY to suit the building and its services, the system includes extensive sub-metering.

NDY attempted to keep the control strategies employed for their new headquarters as simple as possible. At the core of these was to maintain the building’s primary cooling systems in efficient operation.

“An important consideration for us is the management of the chilled-water temperature and the humidity in the space,” says Forbes, whose role with NDY extends to managing the services of the building.

Forbes says there are two measures in place to ensure this is achieved. The first is a floating chilled-water set-point that remains above the dew-point in the office. The second is the dehumidification of supply air to ensure that the dew-point does not rise to the point where the secondary chilled-water temperature climbs too high.

the heating and cooling

set-points are separated

to ensure that we avoid

the mechanical system’s

cardinal sin of heating

fighting cooling’“The heating and cooling set-points are separated to ensure that we avoid the mechanical system’s cardinal sin of heating fighting cooling,” he says.

Aiding the efficient operation of the HVAC system is the economy-cycle cooling available on the top-floor air-handling systems, which again are controlled by the BMCS.

Daylight sensors installed on the lighting controls also ensure lighting on the perimeter is reduced when sufficient daylight is available, while motion sensors deactivate lights during non-occupancy.

“A good quality controls system cannot be underestimated,” says Forbes. “We’ve seen it at our building and on all the sites we have been involved in.

“It is essential that the relevant information is readily accessible. Overly complicated building management systems make it difficult to interrogate the operation of the installed equipment, and lead to people not utilising the systems that are supposed to help them.”

Forbes says the accuracy of information is also critical.

“This often suffers at the end of a new building project, as timeframes become restricted,” he says. “The buildings that we have seen perform best are those where an effort has been made to ensure that all the information is valid. This is especially critical in the sub-metering systems, as there can be many trades involved in their installation.

115 Batman St received 5 star Green Star ratings for Office Design V2 in 2008, and As Built V2 and Office Interiors V1.1 in 2010.

eColi br i u M • MAY 201346

C O V E R F E A T U R E

“Good historical data is also a key,” he says. “It is imperative that the steps you take can be tracked, monitored and compared to previous data.”

ProVen PerforMAnCeIt is more than four years since NDY took occupancy of its new digs in December 2008, and the building continues to operate as designed, with energy and water consumption estimates realised.

overly complicated building

management systems make

it difficult to interrogate the

operation of the installed

equipment and lead to

people not utilising the

systems that are supposed

to help them’The passive chilled beam system is said to have coped extremely well during Melbourne’s recent run of hot summers, and has been found to be provide outstanding indoor conditions during these periods.

Lighting efficiency of the base building has exceeded expectations, and is less than 2W/sq m per 100 lux.

Having achieved a 5 star Green Star rating for Office Design V2 in 2008, followed by 5 star Green Star As Built V2 and Office Interiors V1.1 in 2010, the fact this project was the first refurbished building to achieve the three-peat is an achievement in itself.

That it has since also tracked well ahead of a 5 star NABERS Energy base building rating and won numerous awards is testament to NDY’s commitment to sustainable, energy-efficient design.

“It has been an invaluable experience,” says Forbes. “Designing buildings services is the core of our business, but being able to design, deliver and occupy the one building has given us all valuable insight into the challenges that our clients face.” ❚

115 bAtMAn st At A glAnCe

the equipment

Adiabatic condenser: Powerpax(MullerIndustries)BMCS: Schneider,AndoverContinuumChilled beams:   frengerSystemsDampers:  HolyoakeCompressor chiller:  PowerpaxPumps:  KSBAjaxPumpsGas-fired boiler:  HuntHeatingFans:  fantechVAV system:   CelmecInternational

the professionals

Architect: e+architectureBuilder:   ConstructionEngineeringClient:  NormanDisney&YoungControls contractor:   SchneiderElectricLead consultant:   NormanDisney&YoungMechanical services contractor:  A.E.Smith

NDY’s new headquarters demonstrates that the firm can practise what it preaches.

did you know?NDYwontheAIRAH2012AwardforExcellenceinSustainabilityforitsworkontheMelbourneWaterDataCentre.

Gotowww.airah.org.au/ecolibriumtoreadthearticlefromtheApril2013issue.