8 Solutions’ Nigel Laws highlights the pros and cons of introducing outside air into the data centre

With recent energy prices increasing by up to 10% and future rises expected, the pressure to reduce data centre energy costs along with CO2 emissions has never been greater. Introducing free cooling is becoming more popular, reducing the power demand from the Air Conditioning plant, and thus reducing operational costs and the data centre’s carbon footprint. However, according to Nigel Laws, Business Development Manager at 8 Solutions, a specialist at increasing efficiency and mitigating against the risk of down-time in critical facilities, there are vital caveats to consider.
Nigel explains: “One important consideration is to remember that the main purpose of free cooling is not to save money at any cost, but to provide support to your data centre in the most efficient way. Free-cooling is a cost-effective and environmentally friendly way of cooling a data centre but there are a number of requirements that must be considered if direct free cooling is to be introduced.

“One of the main problems of introducing outside air directly into a data centre is the contaminant load that is subsequently presented. The physical location of the data centre has a significant impact on the air quality being introduced. For example, in urban areas, diesel particulate matter creates a whole host of problems, as does gaseous and chemical contamination, a major problem for data centres situated near major roads, and industrial & sewage treatment plants, both causing contamination levels high enough to exceed the IT equipment manufacturer’s warranties. Even a data centre situated near parkland will encounter a different set of contaminants from insects and pollen.

“In order to counteract the impact of contaminants introduced from outside air cooling, there is an increased need to manage humidification and compensate for airbourne contaminates. Specialist data centre cleaning services should be re-addressed, and environments need careful monitoring to counteract inbound contamination.

Following the removal of lead in the manufacture of printed circuit boards and other equipment (EU Directive 2002/95/EC), printed circuit boards are now much more susceptive to corrosion, and adding outside air directly into the data centre may increase operational risk. Data centre equipment manufacturers are now tightening up their operating tolerances, and this has led ASHRAE technical committee TC9.9 (2011) recommending tighter tolerance of copper & silver corrosion levels. Earlier this year a newly revised ANSI/ISA -71.04-2013 standard was announced (“Environmental Conditions for Process Measurement and Control Systems: Airbourne Contaminants”), confirming this risk.

Nigel concluded, “One of the most important factors to consider is that the introduction of outside air can result in power usage effectiveness (PUE) savings of up to 30%, a significant financial saving. Although there are clearly resilience implications, compounded by further air containment solutions inside the data centre (reducing bypass air), specialised data centre environmental management will ensure the financial benefits from PUE savings far outweigh the risk of potential downtime.”