Ecolibrium. Cloud control. Keeping data centres cool. OCTOBER 2018 VOLUME 17.9 RRP $14.95 PRINT POST APPROVAL NUMBER PP352532/00001

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1 Ecolibrium OCTOBER 2018 VOLUME 17.9 RRP $14.95 PRINT POST APPROVAL NUMBER PP352532/00001 Cloud control Keeping data centres cool.

2 COVER FEATURE Cloud control Such is the growth in data centres globally that researchers have predicted the ICT industry could consume as much as 20 per cent of the world s electricity supply by Sean McGowan takes a look at three trends impacting HVAC data centre design, both here and around the globe. Despite the ethereal nature of the term the cloud as it applies to modern technology, the reality is that most of the data we rely on every day from and Facebook to Netflix, EFTPOS systems, traffic signalling and controls and so much more is stored within physical data centres located around the world. And with more and more of us adopting connected technologies each year, the greater need to store more data. But it s not just the number of connected technologies that is driving the demand for more data centres it is also the speed at which our technologies are generating, connecting and transferring data. Ultimately, this means more storage, faster processing and more energy to keep it operating 24/7 to suit our global lifestyles. Australian data centres consumed 7.3TWh (or 26.3PJ) of electricity back in 2013 representing 3.9 per cent of the nation s total electrical energy consumption. The current US experience (where 90 billion kw hours of electricity are consumed by data centres every year) would suggest this figure has grown exponentially since. Given that energy represents one of the biggest costs of business to data centre operators, the focus on energy-efficient cooling and reducing capital risk are among the key drivers of new data centre design and operation. And at the centre of this design challenge is the HVAC industry. FREE COOLING Mark Toner is the manager of data centres and telecommunications vertical at A.G. Coombs. He says the majority of data centre projects under construction in Australia are for commercial purposes and being built in response to this insatiable appetite for 24/7 computing power. Some of the facilities A.G. Coombs is involved in are planned to be over 50MW in size. With such enormous scale, designs must allow for infrastructure failures, maintenance requirements and life-cycle upgrades without interruption of services. At the facility level, resilient, reliable and energy-efficient HVAC remain key priorities in the design, says Toner. 38

3 COVER FEATURE Resilient, reliable and energy-efficient HVAC remain key priorities in the design And while concurrent maintainability crucial to the ongoing, uninterrupted operation of a data centre is always top of mind for designers, so too is energy efficiency. The availability and cost of energy to supply some of our biggest data centres will rival the energy consumption of heavy industry of the past, says Toner. Cooling is a big part of the energy profile and therefore a priority. Any efficiency gains and lower energy consumption in cooling plant will translate to the operator s bottom line as well as improved environmental credentials. Best practice in data centre HVAC design right now is based around leveraging freecooling strategies wherever and whenever possible. The aim? Reduce the amount of electrical energy consumed for cooling. Toner says the trend leans more towards indirect free cooling solutions, but that direct free cooling also has its supporters. Indirect free cooling designs make use of outside air to cool a data centre s inside air without introducing humidity and outside contaminants directly into the data centre s white space or data halls where the ICT (information and communications technology) equipment operates. Technologies being used to achieve free cooling include high-efficiency air-handling plant with water-side economisation, and high-efficiency chillers with integrated free cooling that run elevated chilled water temperatures. The latter is often coupled with adiabatic precooling to drive further free-cooling benefits. Other design innovations include hot and cold-aisle containment solutions. These are now well-documented and standard inclusion in the design of most data centre white spaces. The evolution of ICT equipment is also influencing data centre HVAC design. Since 2015, ASHRAE specifications have promoted the application of higher temperature and humidity bands within data centre white spaces. The aim is to lower the electrical energy consumption associated with cooling. Technology vendors are responding with ICT products and equipment that will tolerate operating at higher temperatures and humidity. As legacy ICT products are replaced through life-cycle replacement, or new data centres are commissioned with

4 This data centre in Frankfurt was the first in the world to gain a LEED Platinum rating. It uses 30 per cent of the power of a conventional data centre. COVER FEATURE new ICT products, greater leverage can be made from these higher temperature and humidity bands, says Toner. Running elevated temperatures in the data centre also provides a window to use free cooling, driving down the costs of cooling. In recent designs, we have been using indirect free cooling through the use of integrated free-cooling chillers running elevated chilled water temperatures to data centre CRACs (computer room air conditioning), thus maximising the window of free cooling available. MEASURING EFFICIENCY Power usage effectiveness, or PUE, is the common metric for assessing a data centre s energy efficiency. It effectively means that the closer the PUE value is to 1, the more energy efficient the facility is. According to The Frame Group s engineering design manager, Arsalan Shahlaee, M.AIRAH, traditional data centres often have a PUE value closer to 2, which means for every 1kW of IT power consumed, 2kW of total facility power is required to support the IT load. He says the best PUE a data centre owner can wish for is 1.0; however, it is very difficult to achieve. The current benchmark is 1.15 to 1.25 meaning that for every 1kW of IT power, only 150 to 250W (or 0.15 to 0.25kW) of power is required for HVAC, other plant and equipment supporting the space, Shahlaee says. PUE is the common metric for assessing a data centre s energy efficiency We have seen 10-year-old data centres operating with a PUE close to 1.8 and as high as 2.5 due to the use of CRAC with constant-drive fans, and chillers without VSDs in conjunction with very simple control systems that do not adjust the HVAC plant in accordance to cooling demand. The PUE value is normally written into the service level agreements (SLAs) between a data centre and its tenants, with cost penalties applied for not achieving the agreed value. A data centre s PUE can also be important when attracting tenants to co-location sites. Yet according to Martin Howland, technical director for building engineering at AECOM, PUE is not the be-all and end-all when measuring a data centre s energy efficiency. Rather, he says looking at a number of different ratings will provide users with different aspects of efficiency. Data Centre Infrastructure Efficiency (DCiE) provides users with an efficiency metric more suitable for use by the IT users, Howland says. Carbon usage effectiveness (CUE) takes into account the embedded carbon content in the energy sources being consumed. 40

5 Although utilising large chillers and CRAC units, this Queensland data centre also makes use of free cooling. COVER FEATURE PUE is a metric that many can understand and uses a transparent formula that can t be easily manipulated. Yet Toner says it really only provides a relative measure of a data centre s energy efficiency, and may in fact distort actual energy consumption trends. PUE does not necessarily provide you with a game plan for driving down net consumption, he says. MODULARISATION The increasing scale of greenfield data centres is driving a trend towards increasing modularisation in the construction program, with many data centres operators adopting a modular approach to HVAC plant. This in turn provides them with scalability while reducing initial capital costs. For many years now, scalable designs have been a priority for data centre facilities, as they provide the data centre operator with the ability to align capital expenditure with client revenue, says Toner. Scalable designs are achieved through modularisation of both the white spaces (data halls) and grey spaces (plant areas) of data centres. Modularising key areas of the data centre facility design, together with industry innovation and client demand for fast build programs, has allowed prefabrication strategies to flourish. Some commercial data centre operators might punt on their ability to attract new clients, Toner says. But most will wait for a key anchor tenant or tenants or a strong pipeline of clients before they commit to multi-million dollar capital works. When new data centre projects are given the green light, HVAC contractors such as A.G. Coombs are increasingly being confronted with aggressive construction programs. The main driver? The anchor tenant s business plans. It is in such projects that off-site prefabrication becomes a key strategy to enable parallel construction activity. This in turn compresses the overall build time, ensuring the data centre is up and running in the shortest time possible. Toner says the structural elements of a new data centre are usually built on site. Internal modules can be fabricated and pre-commissioned concurrently offsite, before they are installed before final commissioning. There is a continuum of prefabrication strategies, he says. In its simplest form, it could be pipe and duct assemblies standalone or built into vertical and horizontal modules. A more detailed approach might include complete, multi-service plant assemblies. Even entire power and cooling plant rooms, and data hall modules are being fabricated offsite before being transported and installed when the build program calls for them. As well as enabling shorter construction programs, prefabrication is also providing other key project benefits. These include safer work environments, with more work being done in controlled factory environments away from the risks of construction sites, and improved quality control as a consequence. And prefabrication is also reducing waste and associated costs on large data centre projects. Prefabrication commands precision through both the design and fabrication phases, says Toner. This precision reduces the risk of rework onsite, and the risk of construction materials waste both of which reduce cost. With a proliferation of big new data centres being built around the country, one wonders what percentage of the nation s electrical energy data centres will demand in the future, particularly in light of researcher predictions. What that may do to electricity availability and cost in Australia is sure to add more heat to what is already a much debated, and largely unresolved, issue. 42