Intelligent Data Centres Issue 28 | Page 23

demonstrated by the BodenType DC project and it can be simply achieved by collecting aggregated server data that the cooling control system can use to set their fan cooler supply and extract speeds .
One consequence of targeting a constant CPU temperature is an interesting relationship between the instantaneous Power Usage Effectiveness ( iPUE ) and the temperature increase between the cold and hot areas , the ∆T , in the data hall .
Finally , holistic cooling control is not only restricted to direct fresh air-cooling systems , but the approach can also be readily applied to Computer Room Air Handling units and it is a vehicle to lower the ( annualised ) ISO PUE simply by improved fan speed control . ◊
In the north of Sweden , the three highlighted heat transfer processes can be performed using an approach called direct fresh air cooling , where the outside air – which is usually cool – is carried directly into the data hall via convection , using large cooling fans , where it is pushed towards the entrance of the aircooled servers . www . intelligentdatacentres . com