Temperature control for data centres: Why ambient cooling is overtaking compressor technology


Change is afoot in the way in which data centres are cooled. And in a growing sector where potential energy savings could comfortably sit in the hundreds-of-millions, it’s a significant change for data centre consultants and specifiers.

A shift towards ambient

Historically, compressor or refrigerated technology has been the system of choice in a data centre, often with an adiabatic cooler installed to dissipate the heat generated by the compressor. The performance of this conventional chilling technology has served the mission critical data centre sector well thus far.

Now though, we’re seeing a distinct shift in popularity from traditional compressor based chilling methods to far more energy efficient ambient cooling technologies, with a particular focus on adiabatic solutions. And there are two main drivers for this change:

  • Continued investment in the construction of new or extended data centres: The global data centre construction market is estimated to grow from $14.59bn in 2014 to $22.73bn by 2019
  • A significant improvement in the operating parameters of server technology: With modernisation, comes state-of-the-art server technology which is capable of withstanding higher temperatures whilst maintaining optimised performance and reliability

Directly cooling equipment

Historically, ambient cooling equipment has been unable to cool data centres to within the right temperature range, which created an industry reliant on refrigerated or compressor led solutions. Now, thanks to more adaptive build methods and the marginal (but vital) increase in server temperature resilience, the temperature parameters of data centres have risen to a range which ambient cooling technology can comfortably achieve.

In other words, instead of cooling the compressor, adiabatic equipment is now directly cooling the data centre equipment itself. This is reducing CAPEX expenditure by eradicating an entire chiller from many new build specifications.

An energy efficient solution

Crucially, adiabatic and other ambient cooling equipment achieves lower Energy Efficiency Ratios (EER) than compressor based chillers. Take the example of a typical compressor chiller which will consume 1kW of energy for every 3-4kW of cooling delivered.

Compare this to an equivalent sized adiabatic solution, which for the same 1kW of energy consumed, will deliver up to 75kW of cooling.

In terms of EER, this difference translates as an approximate EER of 4 (4kWth/1kWe) for a conventional compressor solution, and an impressive EER of around 75 (75kWth/1kWe) for the equivalent ambient solution. This of course, translates to substantial energy and cost savings for energy-hungry mission critical environments.

Legacy data centres

And the benefits are not restricted to new data centres. Older data centres which house older style servers will still rely on compressor or refrigeration chillers to dissipate enough heat from the data centre, and maintain an internal building environment which meets the operational temperature thresholds of dated server technology.

That said, given that most leading ambient coolers are installed externally, retrofitting additional cooling technology to supplement an existing compressor solution is a highly viable option for many older data centres looking to maximise geographical assets and weather patterns to deliver free cooling during certain seasons.

If an older data centre retains its legacy infrastructure but is refitted with state-of-the art servers which can operate at higher temperatures, adiabatic cooling equipment can be retrofitted to the same inlets as older equipment.

Want to know more?

To discuss our recent projects in the data centre sector, or to see how we can support your next project, call Transtherm’s dedicated team of mechanical engineers on +44 (0) 24 7647 1120.