Managing airflow in a data centre

With soaring wholesale prices pushing up electricity bills, it’s more important than ever for businesses to assess energy usage and operational effectiveness.

According to a report by McKinsey, the IT industry as a whole consumes 2% of the world’s energy, and will generate as much CO₂ as the airline industry by 2020. Data centres contribute a huge part of this energy consumption, in fact, research as far back as 2009 revealed the figure is close to 1.5% of Australia’s total energy consumption.

More than likely, this figure would have significantly increased considering the substantial number of new data centres that have been built here since then. Data centre containment and cooling is essential, this much is known. But, not all containment is equal, and most businesses don’t know that a combination of the right containment and cooling configuration will save them many thousands of dollars every year.

Many businesses install containment and automatically assume their energy usage will be cut, while others tinker with the cooling configuration and disregard the impact of air mixing. Even though containment was first introduced into IT facilities 11 years ago, up to 85% of STULZ customers surveyed still aren’t using containment as a method to better utilise distributed airflow, meaning their critical infrastructure may either be ineffective or inefficient or both, and could be costing them. Given there have been significant innovations in fan and compressor technology during this time, why would there not be a larger emphasis placed in these two energy-sapping areas? The truth is, it’s not just about investing in the containment infrastructure, it’s about the method used to manage the environmental conditions within the data centre too.

The cooling challenge

To work effectively, it’s industry best practice for a data centre to have at least a cold aisle/hot aisle configuration, use of a containment system and blanking panels in the racks. This structure ensures all the cool air passes through the front of the servers with the same airflow quantity and temperature. The absence of this arrangement jeopardises an effective airflow management strategy and can result in:

• Risk of IT system failure — Cool air is not provided in all parts of the rack and hot spots develop. 
• Poor efficiency — It is a misconception that to maintain optimum temperatures you need to over cool the supply air. Many data centres are uncomfortably cold in the cold aisle. Our audit service has found that 60% of facilities are using more than twice the airflow needed by the IT equipment.
• Escalated costs — When air is allowed to recirculate within the rack or between the aisles, it is simply wasted energy. Most users are deploying containment because they can see the benefit of eliminating air mixing in the room and getting a more constant and consistent air temperature on to their IT equipment. Plus, they ‘hope’ that it will give them greater energy efficiency too.

A holistic solution

The first step before one races out and installs containment is to understand how your data centre is really working. We now live in a world where every day we hear ‘data’ is king and ‘it’s all about the data’, yet many operators are making investment decisions without it or certainly through poor or insufficient data. The process should always start with a comprehensive real-time thermal audit of the data centre using multiple sensors. This audit will provide ‘granular’ level conditions such as floor pressure, temperature at the racks and cooling equipment over a period of time.

The efficiency gap

It may sound obvious, but the longer the audit the better the data. This measure will tell you how effective or how well the cooling equipment’s efforts are being utilised. The second step involves recording the IT loads and estimating cooling equipment capacities, and then calculating the difference. This measure will tell you whether you are providing this cool air in an efficient manner — we call it the ‘efficiency gap’. It is at this point, in most cases, that the evidence will be overwhelming.

Real-time monitoring

Once the containment solution is installed, what next? With clever real-time monitoring systems, you can comfortably tweak the fan speeds and adjust environmental settings of the computer room air-conditioning equipment and immediately see the effects of this change. You keep tuning or tweaking until you reach the optimum or have found a balance between SLAs and efficiencies.

Optimisation

It is important to ensure that the during this process the raised floor (if one exists) is correctly balanced, and the racks are sealed with blanking panels in any empty spaces, and any other non-productive openings are also sealed. This process is called optimisation. Once this is completed the data centre’s new power consumption can be measured and the predicted savings will be visible. And with more available room cooling capacity businesses can now deploy additional IT projects or other investments, as they have more capital to do so. But the process doesn’t stop there; IT rooms continuously change, new racks go in, servers are added, removed or replaced, floor grilles are adjusted, and computer room cooling equipment controls are adjusted. All of these will impact and even destroy all the hard work that was done during the optimisation phase. Therefore, it is recommended that an optimisation plan be incorporated into any maintenance regime you have with your service provider.

Airflow management

A managed approach to airflow management will effectively reduce the power consumption of a data centre and will result in significant cost benefits. It’s that simple. By investing in a holistic containment solution that now entails consideration of your cooling equipment and configuration, you can proudly say that you have contributed to your employer’s CSR policy, without compromising system resilience and extending equipment life.

*John Jakovcevic is the ANZ Managing Director of STULZ Australia and New Zealand. STULZ Australia is a technology leader, providing resilient and energy-efficient cooling solutions and services for mission-critical applications in order to support lives, critical data, our economy and our future.

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