The U.S. EPA recently published the final draft of their ENERGY STAR® Computer Program specifications (Version 6). The final draft contains some minor changes from the previous one, including:
- Equalized power supply unit (PSU) incentives for internal and external power supplies
- Adjusted Typical Energy Consumption (TEC) levels for desktops and graphic cards
- Long Idle power consumption in place of Sleep Mode power for TEC calculation for those systems unable to implement Sleep Mode
- Adjusted notebook definition and weightings. The definition of a notebook now includes models with reversible screens and integrated keyboards (formerly “Tablet Computers”)
- Added incentive for Energy Efficient Ethernet capability
Products without keyboards continue to be excluded from this specification. Defined as “slates or tablets”, testing and performance requirements for these products will be included in the next revision (v6.1), expected to be completed in the spring of 2014.
As in the current version 5, the new program requirements continue to focus on the computer’s TEC while in non-active modes. In order to meet the ENERGY STAR requirements, the computer’s “measured” energy consumption, ETEC (see Equation 1), must be less than the maximum energy consumption limit allowed, ETEC_MAX, calculated based on the computer’s system capability (see Equation 2), as shown below.
Equation 1. ETEC Calculation for Desktop, Integrated Desktop, Thin Client, Notebook Computers (Source: ENERGY STAR)
Where: POFF = measured power consumption in Off Mode (W), PSLEEP = measured power consumption in Sleep Mode (W), PLONG_IDLE = measured power consumption in Long Idle Mode (W), PSHORT_IDLE = measured power consumption in Short Idle Mode (W), and TOFF, TSLEEP, TLONG_IDLE, and TSHORT_IDLE are time mode weightings as specified in the program spec.
Equation 2. ETEC_MAX Calculation for Desktop, Integrated Desktop, and Notebook Computers (Source: ENERGY STAR)
Where: ALLOWANCEPSU = an allowance provided to power supplies that meet the optional higher efficiency levels as specified in the spec, TECGRAPHICS = the discrete graphics allowance as specified in the spec, TECBASE = the Base allowance for Desktops and Integrated Desktops as specified in the spec, and TECMEMORY, TECSTORAGE, and TECINT_DISPLAY = adder allowances as specified in the spec.
The final draft includes the previous draft incentive for using a “higher-than-required-efficiency” power supply by introducing an “allowance” factor in Equation 2, raising the allowable TEC and making it easier to meet. Allowances for the minimum efficiencies of internal and external power supplies were harmonized in this draft and are shown below in Table 1.
Table 1. Power Supply Efficiency Allowance (Source: ENERGY STAR Computer Program Requirements Ver.6)
Meanwhile in Europe, the first Ecodesign Directive Computer Implementing Measure entered into force a few weeks ago. The mandatory efficiency standard is based on the current ENERGY STAR voluntary program specifications, Version 5, with some notable differences, including:
- The Ecodesign standard covers slates and tablets, while the ENERGY STAR program excludes them.
- The Ecodesign standard includes some independent power consumption limits for sleep mode, lowest power state, and off mode, which the ENERGY STAR program doesn’t have.
The new ENERGY STAR Version 6 specification takes effect on April 28, 2014. For a copy of the program requirements, click here. Some of the Ecodesign Directive computer requirements take effect immediately, but the majority will become effective on July 1, 2014. To download a copy of the standard, click here.