$$\mathrm{WUE_{site}} = \frac{V_{\mathrm{water}}}{E_{\mathrm{IT}}}$$

Equation 1 · Datacenters

Comparing the Main Approaches to AI Datacenter Power and Cooling

This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.

Water Usage Effectiveness, the metric LBNL uses throughout its modeling, is defined analogously to the more familiar Power Usage Effectiveness: $\mathrm{WUE_{site}} = \frac{V_{\mathrm{water}}}{E_{\mathrm{IT}}}$. where $V_{\mathrm{water}}$ is total on-site water consumption in litres and $E_{\mathrm{IT}}$ is the electricity delivered to IT equipment, giving WUE units of litres per kilowatt-hour rather than PUE’s dimensionless ratio [ 4 ] . What LBNL’s simulations across roughly 965 US weather stations and multiple facility archetypes show is that this number is driven overwhelmingly by which heat-rejection route a facility uses at the plant level — an economizer decision layered on top of, and largely independent from, the cooling method at…

Meanings in this article

• $V_{\mathrm{water}}$: total on-site water consumption in litres.
• $E_{\mathrm{IT}}$: the electricity delivered to IT equipment, giving WUE units of litres per kilowatt-hour rather than PUE’s dimensionless ratio [ 4 ].

Equation guide → · Article →