DC-Energy Efficiency Label Draft

Choose your key figures and observe the changes on the label.

Bulding Technology


Information Technology

Annual Energy Consumption Serveri: kWh or % of EIT
Annual Energy Consumption Storagei: kWh or % of EIT
Annual Energy Consumption Networki: kWh or % of EIT

Annual Energy Consumption

This value is used to weight the individual LC values:

PUE - Power Usage Effectiveness

The Power Usage Effectiveness (PUE) is defined according to DIN EN 50600-4-2 as:


These typical PUE values are converted into an energy efficiency index (EEI) between 0 points (worst value) and 100 points (best value) using the formula described below:

CER - Cooling Efficiency Ratio

The Cooling Efficiency Ratio (CER) is defined according to DIN EN 50600-4-7 as:


The value range of the CER is mapped linearly from [1;9] to [0;100] for the energy efficiency index:

ERF - Energy Reuse Factor

The Energy Reuse Factor (ERF) is defined according to DIN EN 50600-4-6 as:


The CER is converted as follows for the energy efficiency index from 0 to 100 points:

Load Correlation Server

The load correlation (LC) describes how well IT utilisation correlates with energy utilisation. The already established key figure IT Equipment Utilisation of Servers (ITEUSV) is used as a value for the annual average CPU utilisation of all servers.
It is defined:


Load Correlation Storage

The useful work of the storage system usually consists of storage space allocation. It is therefore defined that the load correlation for storage systems (LCStorage) is the ratio between percentage storage utilisation and proportional energy consumption of the storage to its maximum energy consumption:


For storage systems, it can be argued that their energy consumption does not correlate with storage space utilisation, but rather with data throughput during read and write activities. Therefore, if the storage space utilisation is taken as the unit of useful work, the energy consumption remains constant. To simplify, both energy consumptions EStorage and (PStorage_max * t) can be set equal, which leads to a denominator of 1 and allows the following simplification of the calculation rule:

Load Correlation Network

The load correlation of network devices is defined as the ratio of the Network Utilisation (ratio of the number of connected ports with the number of available ports) and the quotient of measured energy consumption to the maximum energy consumption with full port occupancy:



Ports here refers to the number of physical ports of all multiport bridge devices.