Energy efficiency


so obviously depends on it. Other data centres may present a less well maintained, dirtier environment. And dirtier servers will logically benefit more from restoration to cleanliness.


Also, because of time constraints, the survey was limited to cleaning the fan intake area on the outside of the server enclosure. If the server could have been shut down for enough time to clean the fans and heatsinks within, improved airflow, lower fan loading and significantly greater power saving benefits may have been achieved.


Scaling up the benefits The corrected survey results show a power saving of 1.65 W, and energy savings of 0.28 kWH for a single server running over one week. These figures may not seem impressive until we consider their implications for a complete data centre running over a year. If a server taking 87.14 kW can save 0.28 kWH/week, then a complete server cabinet drawing 3000 W can save (3000/87.14) x 0.28 = 9.64 kWH/week.


This equates to 9.64 x 52 = 501 kWH/year. For a data centre that has, say, 400 server cabinets, the yearly saving is 400 x 501 = 200,000 kWH. For a data centre paying 10p/kWH,


this represents a yearly saving of £20,000. Reduction in CO? emissions is significant as well: According to UK Government figures, saving 1 kWH of electricity is equivalent to saving 0.43 kg CO?. The data centre would save 200,000 x 0.43 = 86,000 Kg CO? in a year.


Conclusions


The University of Southampton review of the survey results showed that, in their opinion, the cleaning procedure is highly effective. The review also concluded that both more contamination on the server and


heavier process loading on the CPU could increase power demand and therefore potential for saving. A simple extrapolation from single server week to data centre year shows how significant the savings will be.


Investment in a professional data centre decontamination service will show a rapid return on investment. The CO? saving is also valuable in a climate where both legislative forces and preservation of public image put pressure onto organizations to reduce – and be seen to reduce – their carbon footprint.


The corrected survey results show a power saving of 1.65 W, and energy savings of 0.28 kWH for a single server running over one week. These figures may not seem impressive until


we consider their implications for a complete data centre running over a year. If a server taking 87.14 kW can save 0.28 kWH/week, then a complete server cabinet drawing 3000 W can save (3000/87.14) x 0.28 = 9.64 kWH/week


26 | DATA CENTRE SOLUTIONS | www.datacentresols.com Winter 2010


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