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Equation 5 · Part 1 · AI Datacenter Power and Cooling: A First-Principles Introduction

Symbol E_facility

PUE=EfacilityEIT.\mathrm{PUE} = \frac{E_{\mathrm{facility}}}{E_{\mathrm{IT}}}.
EfacilityE_{\mathrm{facility}}

What this part means

EfE_facility occurs above the fraction bar. The numerator is divided by the entire denominator below it.

Its job in the formula

EfE_facility occurs above the fraction bar. The numerator is divided by the entire denominator below it.

The passage around this formula

Two ratios recur throughout this series, and both are simpler than their reputation suggests. Power usage effectiveness compares the total electricity a facility draws to the electricity that reaches the computing equipment itself: PUE=EfacilityEIT\mathrm{PUE} = \frac{E_{\mathrm{facility}}}{E_{\mathrm{IT}}}. The Green Grid, the industry consortium that introduced the metric in 2007 and later consolidated its guidance into a single reference document, defines it plainly: “PUE for a dedicated building is the total facility energy divided by the IT equipment energy. PUE is an end-user metric used to help improve energy efficiency in data center operations” [ 5 ] . An ideal value is 1.0, meaning every watt drawn by the site reaches the computing load;…

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A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the surrounding passage

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