DC-Energy Efficiency Label Draft

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:

With:

• E_DC the total energy consumption of the data centre (annually) in kWh,

• E_IT the energy consumption of the IT equipment (annually) in kWh.

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:

• PUE > 2.5 is set to 0 points, PUE < 1.1 is set to 100 points.

CER - Cooling Efficiency Ratio

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

With:

• Q_dissipated as the total (annual) amount of heat dissipated from the data centre in kWh,

• E_cooling as the (annual) energy consumption of the cooling systems in kWh.

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

• CER ≤ 1 is set to 0 points, CER > 9 is set 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 (ITEU_SV) is used as a value for the annual average CPU utilisation of all servers.
It is defined:

With:

• LC_Server as dimensionless load correlation of the servers (0 to 100%),

• ITEU_SV as average (annual) CPU utilisation of the servers (0 to 100%),

• E_Server as (annual) energy consumption of all servers in kWh,

• P_{Server_max} as the sum of the maximum power consumption of all servers in full load mode in kW,

• t as the measurement period in hours, for an annual value this corresponds to 8760h.

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 (LC_Storage) is the ratio between percentage storage utilisation and proportional energy consumption of the storage to its maximum energy consumption:

With:

• LC_Storage as dimensionless load correlation of the storage systems (0 to 100%),

• Storage_Utilisation as average (annual) storage space utilisation (0 to 100%),

• E_Storage as (annual) energy consumption of all storage systems in kWh,

• P_{Storage_max} as the sum of the maximum power consumption of all fully occupied storage systems in kW,

• t as the measurement period in hours, for an annual value this corresponds to 8760h.

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 E_Storage and (P_{Storage_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:

With:

• LC_Network as dimensionless load correlation of the network (0 to 100%),

• Network_Utilisation as the average (annual) utilisation of physical ports (0 to 100%),

• E_Network as (annual) energy consumption of all network devices in kWh,

• P_{Network_max} as the sum of the maximum power consumption of all network devices with fully occupied ports in kW,

• t as the measurement period in hours, for an annual value this corresponds to 8760h.

And:

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