Data centers: What does it take to heat things up?

Data centers: What does it take to heat things up?

Keeping things cool has long been a mantra for data center operators, but new research suggests it may not be essential for everyone.

Data centers have historically operated at temperatures ranging between 64° and 68° Fahrenheit (or 17° to 20° Celsius), prompting them to spend approximately 44 percent of their total power budgets on cooling.

Originally, the varied mix of equipment and associated warranties dictated these relatively cool temperatures, and service level agreements (SLAs) often included explicit language about how much deviation was acceptable.

But while it's true temperature control can affect equipment reliability and appropriate management and monitoring is needed for business continuity, new research supports the idea that higher temperatures are beneficial for most data centers.

So, how do you know when to raise the temperature, and by how much? Are there any changes recommended to reduce business risks?

Should every data center cut back on cooling?

When we ask, many data center managers can’t tell us why they set the thermostat at a particular temperature. It’s just the way it has been done for years.

But when well-known companies -- including Facebook, Google, Yahoo!, Korea Telecom and others -- publicize their high temperature ambient (HTA) successes at 80°F and above, we all pay attention. And when research and on-the-ground examples support the efficacy of HTA data centers, suddenly we are all tempted to reduce our cooling costs by just pushing up the thermostat.

Before arbitrarily cutting back on cooling and letting the ambient temperature rise, however, as a data center manager, you’ll want to review your equipment warranties, SLAs and compliance requirements. For those responsible for data centers supporting legacy systems that require lower operating temperatures, or for those whose organizations are subject to extremely stringent compliance requirements, you’ll want to continue to take a very conservative approach. 

HTA Best Practices

That said, today’s major vendors of data center equipment generally design and warrant systems and products for reliable operation at 40°C or 100°F. It makes economical sense to take advantage of the latest product specifications and warranties. This means considering simple as well as more involved changes:

  • Thermostat-only changes. Data centers potentially reduce cooling costs by 4 percent for every 1°C increase in operating temperature. (Cooling accounts for up to 44 percent of the power consumed in an un-optimized data center, which is the typical design being implemented in emerging economies.)
  • Retrofitting the data center. Besides raising ambient temperature, hot and cold air aisle separation drives up the savings, and replacing chillers with economizers (heat exchangers) can yield dramatic savings. In one of Intel’s data centers (with 900 production servers), retrofitting and raising the temperature to 33°C or 91.4°F has translated to a 67 percent annual power savings ($2.87 million in a 10MW data center).
  • Optimized data centers. Hot aisle containment, energy-efficient servers and a node-level power management solution capable of dynamic resource management (e.g., power capping servers, racks and rows; adjusting server performance and fan speeds) have been shown to dramatically drive up energy efficiency and support operation at the highest temperatures without increasing risk to the business. Real-world results show power utilization efficiencies can be increased so that IT power utilization improves from 50 percent to 81 percent of the total.  

All things -- and temperatures -- in moderation

Your data center can take some steps to reap the cost benefits of HTA operation. Start with a plan to phase out, relocate or outsource any legacy system that is keeping your data center at the lower, more expensive operating temperatures. As soon as possible, bump up the temperature by one degree or two, to get on a path toward HTA.

However far along you are, an energy management solution may improve your visibility into energy use and thermal patterns within your data center. Among the foundations necessary for achieving power efficiency through HTA practices are real-time visibility and the abilities to log power and temperature data, and to analyze usage trends based on the logged data.

These same capabilities can also enable other energy management practices such as lowering carbon emissions, thus allowing you to expand a data center without exceeding power limits, and efficiently balancing services and workloads to avoid power spikes.

The cost and power savings achievable by adopting HTA as a model may well represent the new norm. The timing is perfect: Data centers currently consume 1.5 percent of all of the world’s power. Annual server energy costs exceed $27 billion. By 2014, these numbers are expected to double. Bumping up your data center’s ambient temperature directly reduces cooling costs and power consumption, and simultaneously reduces CO2 emissions.

HTA makes business sense, and it makes sense for our planet. Get ready for the data center world to heat up!

Photograph of thermostat provided by edb via Shutterstock. Infographic provided by the author.