Schneider Electric’s business development manager for cooling solutions, Luca Melluso, explains how running data centres at elevated air temperatures can cut energy costs by reducing energy used for cooling.
The industry has just started to get comfortable with the practice of running data centres at warmer levels than in the past.
Recently, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) updated its thermal guidelines for data centres.
The guidelines include a breakdown of data centres into four classes with two tiers for temperature management.
The biggest effect of the updated thermal guidelines is that data centre managers now have an authoritative set of recommendations to back up a decision to raise temperatures marginally.
The guidelines have a number of points we recommend keeping in mind.
Firstly, within the recommended ranges, there is a “sweet spot” to hit in finding the optimal balance between reduced energy consumption for cooling, and potentially making the IT equipment work harder.
This sweet spot tends to vary depending on the configuration and assets in
a particular data centre.
Secondly, the performance risk to the IT assets is primarily from rapid temperature changes, not from a marginally higher set point. As long as the temperature is within the recommended range and stays consistent, performance should not be an issue.
And finally, newer server hardware is capable of running reliably and efficiently at higher temperatures, as long as the temperature stays consistent. Fan power consumption in servers, for example, is much more efficient today than 10 or 15 years ago.
When considering the above points it’s vitally important to look at temperature consistency when data centre operators start thinking about raising the target levels.
An audit should help a facility prepare for such a change so that the new set point stays consistent and the facility is not left struggling with air mixing and temperature shifts that could threaten IT equipment performance or erode the expected energy savings.
For data centre managers considering implementing elevated inlet air temperatures in accordance with their guidelines, it’s important to think about how to keep the new set point consistent.
This typically requires multiple factors to be assessed, such as proper air flow management, configuration of hot aisle and cold aisle configurations, including placement of cooling units, possible upgrades to containment to reduce air mixing, as well as placement of temperature sensors within the data centre.
For further reading on optimal running temperatures, Schneider Electric’s energy impact of increased server inlet temperature white paper is available online.
CCN's special data centre feature appears in the December edition of the magazine.