March 2003

"Modern data centres generate massive amounts of heat from computer and telecomms equipment," explains Mark Seymour, Flovent Product Manager at Flomerics. "It is common practice to cool these facilities to normal room temperature through the use of air conditioning, which represents an enormous and unnecessary waste of energy because, unlike an office environment, these spaces are only occasionally required to be occupied by humans for maintenance, reconfiguration or fault-finding."

Ian Bitterlin, Managing Director of Liebert-Hiross UK, states: "The principle of "free" cooling means simply using outside ambient air to cool the return circuit, rather than circulating air that has been physically cooled. A temperature difference of several degrees is required for this to be efficient, and obviously the external air temperature has to be lower than that of the computer room. This means that free cooling is currently only practicable in Northern climes and cooler seasons. However, if the internal ambient temperature of the room were allowed to rise to, say, 35°C, then "free" cooling would immediately become feasible all year round in most parts of the world. This would save enormous amounts of energy, and substantially reduce harmful greenhouse gas emissions. Using a modern, scientific approach to predict the air movement within the room precisely, designers can prevent hot-spots and avoid the electronic systems overheating."

The most common method of cooling computers and telecommunications equipment within a data centre is to distribute large quantities of cool air throughout the entire room at floor level via regularly spaced floor tiles, without attempting to predict the air movement in detail. The problem with this approach is that it is extremely inefficient - the expensively-cooled air inevitably mixes with warm air along the way, developing many local 'hot-spots' and air recirculation zones, all of which waste energy and reduce cooling efficiency. In order to prevent the electronic equipment overheating and provide a "margin for error", designers are forced to over-design the cooling system capacity and increase airflow rates. A more scientific approach to designing and controlling the airflow through the data centre, using modern computational fluid dynamics (CFD) software such as Flovent from Flomerics, enables engineers to predict the 3-dimensional air movement precisely, and arrange the equipment cabinets in an optimal way in order to maximize the use of cool air, and minimize energy consumption.

For a 3D graphical animation illustrating the prediction of air movement through a typical data centre, visit www.flovent.com/dcdemo/.