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Posts Tagged ‘PUE’

New electricity meters in the main data centre

Friday, September 20th, 2013

The IT Division, with the help of Facilities Management, has installed two new energy meters in the main data centre (DC) that will enable us to monitor energy consumed by all equipment within the DC, including the cooling and ventilation systems. The meters will enable us to calculate the Power Usage Effectiveness (PUE) of the DC, which is the ratio of energy consumed by all equipment to that consumed by computing and networking equipment.

The DC’s PUE is in the range 2 to 2.5 depending on external ambient temperature. This means that for every watt going to the computers, another watt or more is going to cooling and ventilation equipment. Various interventions will be undertaken to reduce PUE and minimise energy consumption. At present the DC consumes between 1.1 and 1.3 GWh per annum and the energy bill is now the responsibility of the IT Division.

Under the new electricity accounting regime, the monetary value of energy savings will accrue to the IT Division for one year, and can be invested in further energy efficiency.

Benchmarking Sustainable IT at universities

Friday, October 15th, 2010

Our peers in Australia (CAUDIT) have progressed much further with benchmarking between universities – including benchmarking on the sustainable IT or “green IT” front. South Africa’s equivalent HE IT association, ASAUDIT, has largely adopted CAUDIT’s benchmarking metrics. The Green IT benchmarking metrics are discussed briefly below.

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Preparing to pay for data centre energy usage

Friday, March 5th, 2010

Last week Dolf Krige of the Facilities Management Division presented their plan for monitoring, measuring and managing energy use on campus to the Sustainable IT Competency Centre group. Essentially the first phase implementation comes down to installing 87 intelligent energy meters during 2010 – with the goal of devolving the cost of electrical energy usage, which is currently centrally funded, to departments and divisions. Devolution of electricity costs will concentrate minds and promote energy efficiency because the financial savings will accrue to the user entity.

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Preliminary PUE results for SU’s data centre

Thursday, December 17th, 2009

Continuous energy measurements in Stellenbosch University’s main data centre (DC) have been taking place since April this year. We now have minute-by-minute data spanning the coldest season and some summer months – and the results are starting to become interesting. (more…)

Energy meters now running in the Data Centre

Tuesday, April 14th, 2009

Our IP energy meters are up and running in the University data centre, thanks to the efforts of Conrad Bright and Christiaan Brand. We will now watch the results and learn about the DC’s consumption. The one meter measures total supply to the DC, while the other measures output from the UPSs (i.e. power to computing equipment). The meters started logging at around midnight. The night was cool and the servers not that busy, yet it seems that PUE was in the range 2 to 2.2 (roughly). This means that for every watt going to the computers, another is going to the aircons. It will be interesting to see how it changes as the day heats up.

Next steps are to a) provide a dashboard on this blog and b) correlate readings with local weather data.

Measuring SU data centre Power Usage Effectiveness (PUE)

Tuesday, December 23rd, 2008

The Green Grid recommends the Power Usage Effectiveness (PUE) metric for data centres in order to benchmark and compare energy consumption between data centres and to baseline consumption against which improvements in energy efficiency may be measured.

PUE is defined as:

Total Facility Power
IT Equipment Power

Most data centres operate at PUE = 2 to 3 and some at PUE > 3. PUE = 3 means that for every watt consumed by the computers, 2 watts are being consumed by data centre (or computer room) air-conditioning (CRAC), lighting and power delivery equipment. The goal is thus to get PUE to approach 1. Google, operator of the world’s largest data centres, reports that current state-of-the-art data centres can attain a PUE of 1.2. (more…)