December 3, 2004—Maintaining air temperature at a suitable level in server rooms can present serious difficulties for building managers and service engineers, according to the Building Research Establishment (BRE), a center of expertise in the UK for construction, the built environment, sustainability, energy, fire, and related issues.
BRE says the root of the problem is the ever-increasing heat load generated by IT equipment. “These days minimum computer loads can be as high as 20kW for a typical high-end server cabinet,” says David Butler, who runs BRE’s large Environmental Test Chamber. “Whilst there are ways of dealing with cooling at this level, a number of issues need to be considered and the solution is rarely as straightforward as it may first appear.”
The traditional approach of placing server cabinets in parallel rows to create hot and cold aisles with cold air supplied from the floor void only works with output of around 6kW. Beyond that, the footprint of the server rooms needs to be increased and in some instances this just may not be possible, says BRE. An alternative approach is to introduce higher-capacity cooling systems, but these, by their very nature, will generate more heat and thus increase the risk of damage if there is failure. Water-cooled cabinets can provide an effective solution, but many are wary of the potential damage that would be caused if water were to leak through to the servers.
“Reliability is crucial when the stakes are high, as they are with IT,” says David Butler. “In these cases, it can be worth spending a little time and money assessing the performance of the chosen system before finalizing the decision. Over the past couple of years we have been asked to assess a number of cooling systems in our environmental test chamber and in each case there has been some shortfall or failure that neither we nor the design team could have predicted. Once the problem has been identified, the design team can refine the system until it can be seen to cope with the cooling targets.”
Energy efficiency is another issue that will become increasingly important, according to BRE. “With the Energy Performance of Buildings Directive coming on stream in the next couple of years and further changes to Part L in the pipeline,” says Butler, “designers will need to meet energy consumption targets as well as ensure system performance. There will be a real incentive to look for longer term solutions that will meet future technology improvements.”
For further information, please contact the BRE Environmental Helpline at 01923 664500, or e-mail environment@bre.co.uk.
