Ecolibrium. Living landmark Barangaroo International Towers Sydney scores world-first WELL rating. MAY 2018 VOLUME 17.4 RRP $14.95

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1 Ecolibrium MAY 2018 VOLUME 17.4 RRP $14.95 PRINT POST APPROVAL NUMBER PP352532/00001 Living landmark Barangaroo International Towers Sydney scores world-first WELL rating.

2 London calling One of Canberra s landmark commercial buildings is defying its age thanks to an energy overhaul that has reduced emissions by 37 per cent. By tackling energy efficiency from every angle, one of Canberra s most iconic commercial buildings 221 London Circuit has achieved a reduction in emissions of more than one-third, lifting the NABERS performance of this nearly 50-year-old building from 3.5 to 4.5 stars. The building has long been a part of Canberra s CBD, first opening in 1969 as Electricity House, and served as headquarters for ActewAGL (the ACT s local utility provider) until It was purchased by Molonglo Group in 2008 and refurbished into a modern commercial office in The refurbishment breathed new life into the HVAC systems, including new chiller plant, cooling towers, VAVs, BMS control system and a solar domestic hot water system. In 2015, Energy Action assessed the building at 3.5 stars NABERS energy. Molonglo Group, wanting to unlock the asset s full potential, engaged Energy Action to identify and oversee further upgrades to achieve a 4.5 star rating without the use of GreenPower. The project was not straightforward in any way, as the building had been refurbished multiple times over its life and there was very little low-hanging fruit left for easy efficiency gains; achieving energy savings required innovative and leading-edge strategies. To further add to the challenge, the upgrades were carried out with the building mostly occupied. The subsequent works demonstrated the value of a holistic approach to upgrading pre-loved buildings, beyond conventional replacement of end of life plant. By examining areas such as façade performance, ductwork configuration, latent defects and system interdependencies, most of the HVAC energy savings were realised in a cost-effective manner without major capital works. Key facts 8,588m 2 commercial office building with ground floor cafe and basement parking NABERS base-building energy rating increased from 3.5 stars to 4.5 stars from July 2015 to Dec per cent reduction in electricity use and 34 per cent reduction in natural gas Emissions reduction of 281 tonnes CO 2 equivalent per annum (Scope 1, 2 & 3) $67,000 p.a. saving in avoided energy costs. MAY 2018 ECOLIBRIUM 71

3 Figure 1: Air leakage testing though a fire escape door. CLOSING THE CIRCUIT The building s top floor had significant thermal comfort issues during Canberra s cold winters, struggling to reach temperature set point during morning warm-up. As a result, the central heating system had been scheduled to start up at midnight in an attempt to bring this area up to a comfortable temperature by 8am. An air leakage test confirmed that poor air tightness was the culprit. The air change value was measured in excess of 40ACH50 (air changes per hour at 50Pa), well above recommended values. As a result, most of the heat was being lost through the building envelope. Building works were conducted to seal as many gaps as possible. The main source of leaks was the acoustic ceiling, which was made from perforated plasterboard. This posed a significant challenge because there was no simple way to fill these holes without ruining the ceiling s aesthetic. A solution was devised where coloured acoustic panels were affixed over the ceiling. This allowed the holes to be blocked without compromising the fitout s acoustics or aesthetics. These works improved air tightness from 40ACH50 down to 15ACH50, allowing the HVAC system to more efficiently service this zone. After these works were completed, the winter warm-up time on the plant was reduced from eight hours to one hour, and comfort conditions were easily achieved. The design of existing rigid ductwork is often overlooked on upgrades. In this case, the ductwork configuration was causing balancing issues that required excessive fan energy to compensate. Addressing this provided energy savings that would have typically been overlooked on a conventional upgrade. The centre-zone AHU ductwork had a poorly designed junction where flow to the two risers branched apart. The duct was shaped such that most of the flow went down the north riser, and the southern zones were often starved for flow, even when the supply air fan was running at maximum speed. Due to space limitations, this issue couldn t be rectified by installing a proper splitter damper. Instead, a custom duct scoop was designed and installed into the branching point, such that enough airflow was diverted to the south riser to better balance the system and reduce fan energy. Additional fan energy savings were achieved by fixing various latent defects throughout the floors, such as flexible ductwork that was bent or crushed, or in some cases not connected to diffusers. 72 ECOLIBRIUM MAY 2018 Figure 2: Acoustic panels being installed over the perforated ceiling to improve air tightness

4 Figure 3: Further fan energy savings were achieved by identifying and fixing latent defects, such as this kinked flexible ductwork. IN HOT WATER Although the site s existing domestic hot water system already had several high-efficiency components such as solar collectors and insulated storage tanks, the efficiency suffered greatly from poor design and control issues. The solar collectors were boosted by the central heating hot water plant, which resulted in inefficient operation (particularly in summer) because a 500kW boiler was often required to dutycycle year-round to service a relatively small domestic hot water (DHW) load. Furthermore, the circulation pump operated 24/7, causing most of the residual heat in the system to be lost overnight through distribution losses. The DHW system was de-coupled from the heating hot water plant by installing separate boosters. Although electric heat pumps were the preferred option, they were ultimately abandoned in favour of instantaneous gas-fired units due to space restrictions. server room). All other units served meeting rooms and only required water during scheduled occupancy (or for after-hours AC requests). Retrofitting control valves to every tenant PAC unit would have been prohibitively disruptive and costly, so a more resourceful and cost-effective solution was implemented. Large motorised isolation valves were installed in the plant room for two of the three condenser water risers, allowing most of the system to be isolated whenever the building was unoccupied. The third riser was kept open to provide condenser water to the large server room. This presented its own challenge, as the DHW plant was located close to the building s fresh-air intakes, making it difficult to flue the units in accordance with code. In addition, the circulation pump was placed on a timer and turned off for a few hours every night, helping to retain some heat in the insulated tanks for the next day while still managing Legionella risks. The tenant condenser water system was one of the largest uses of electricity, operating at full flow 24/7. This was largely because downstream PAC units were poorly documented and most equipment wasn t fitted with motorised control valves. A full audit of the condenser water system was carried out to identify all supplementary PAC units and their operating hours. It was discovered that only one PAC unit actually required condenser water 24/7 (to service a small Figure 5: Newly installed motorised isolation valve on one of the three condenser water risers. Hourly consumption (kwh) Before Upgrade After Upgrade Figure 6: Tenant condenser water consumption profile comparison 3 days before and 3 days after upgrade 74 ECOLIBRIUM MAY 2018

5 Figure 7: PV System. COMPLEX CONTROLS Due to the many refurbishments over the decades, the building had a complex mix of HVAC systems, including VAVs, on-floor FCUs and PAC units. The HVAC controls were overhauled, with a holistic approach taken. The central VAV system was used as the priority method for conditioning the zones. Wider temperature dead-band controls were implemented on the on-floor FCUs and PAC units such that these units would only activate if the VAV system was struggling to satisfy heating/cooling demand. Care was also taken to turn off FCU and PAC unit fans wherever possible. Due to restricted air flow through the cooling towers the towers discharge horizontally due to height limits in the plant room the condenser water temperature control strategy needed to be carefully tuned to optimise the trade-off between cooling tower fan energy and compressor efficiency. In addition, a full rebalance of the central and perimeter VAV systems was conducted after hours, all temperature sensors were recalibrated, and sensors in impractical locations were relocated. 76 ECOLIBRIUM MAY 2018 Figure 8: New condensing boilers.

6 Voltage optimisers on each PV panel... provided an improvement in output of approximately 20 per cent. These controls upgrades were followed up with a 12-month program of building tuning and performance monitoring to validate operation and identify further opportunities for improvement. CAPITAL WORKS The height, structure and layout of this building presented considerable challenges to providing an on-site generation solution that would deliver the desired NABERS uplift. To address these issues, the design included maximising the available roof space while maintaining service access and coping with roof sub-structure constraints, wind loadings and multiple obstructions. Due to the nature of the PV layout, it wasn t possible to ensure all panels in a string could receive the same insolation at the same time, presenting a problem that would severely reduce the system output. To address this, the design included voltage optimisers on each panel. The optimisers allowed each panel to operate independently without impacting the rest of the panels in its string when shaded. LESSONS LEARNED Investigate and rectify latent defects as early as possible, otherwise they can undermine your predicted energy savings from controls upgrades Look to the building envelope for ways to reduce heating and cooling loads; the opportunities can be larger than you expected Post-project monitoring and verification (M&V) is an invaluable tool to ensure your upgrades have had the intended outcome. It can be used to identify tuning opportunities and take corrective actions in a timely manner. On this building, these optimisers provided an improvement in output of approximately 20 per cent. MAY 2018 ECOLIBRIUM 77

7 FE ATURE PROJECT AT A GLANCE Estimated NABERS rating (Prior 12 months) 4.5 The personnel Building owner: Molonglo Group 4.0 Project management: Energy Action Building management: Knight Frank Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Jan-16 Feb-16 Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Jan Monthly NABERS Estimate 4.5 Star Target Figure 9: Monthly NABERS monitoring results to date. Furthermore, with the system being remotely monitored, the operation of every panel can be viewed and action taken to correct faults occurring down to panel level rather than the traditional inverter level. Having achieved 4.5 stars, further works are currently underway to improve the resilience of the rating and potentially target 5 stars: An automated fault diagnostics platform is being installed over the BMS to identify new maintenance and controls opportunities to improve energy efficiency performance. The common area lighting is being upgraded from compact fluorescent downlights to LED equivalents, which is expected to halve lighting energy in these areas. As of January 2018, the site had reduced its annual electricity consumption by 38 per cent and natural gas consumption by 34 per cent. A 4.5 star NABERS energy rating has also been achieved. In terms of energy costs, $67,000 per year has been avoided. 78 ECO L I BR I U M M AY 2018 BMS controls: Control & Electric Air leakage tests and draught-proofing: Air Leakage Measurement Australia Solar installation: Clean Energy Corporation Australia Electrical services: Star Group Meanwhile, the site s two 500kW atmospheric boilers were upgraded to high-efficiency condensing boilers under their end of life replacement. With these new boilers, a variable supply temperature control strategy was implemented, resetting the supply set point between 80 C and 60 C dependent on outside temperature. This allowed gas savings to be achieved through reduced thermal losses and operation under condensing conditions. Mechanical services: CCS Group Plumbing services: Zammit Hydronic and Mechanical Figure 10: Level 12 office. Notable sub-system savings include the tenant condenser water system (reduced by 25 per cent), domestic hot water system (down 45 per cent) and the heating hot water pumps (down 40 per cent). Tenant comfort complaints have also been significantly reduced, largely due to the draught-proofing works. The success of the project is further proof that, with intelligent improvements, pre-loved buildings can enjoy a bright future. Ductwork: J. Sainsbury & Co Balancing and commissioning: Superior Balancing Services The equipment Boilers: Automatic Heating Valves: Belimo BMS: Siemens Acoustic panels: Autex Domestic hot water units: Rinnai Solar panels: LG Energy AIRAH would like to thank James Spears, M.AIRAH, for providing this case study, and Dr Paul Bannister, F.AIRAH, for reviewing it. Inverters: SMA Voltage optimisers: Tigo Energy