EPA Publishes New ENERGY STAR Display Specification

Fri, 01/29/2016 - 11:53 -- MrGreen

The U.S. Environmental Protection Agency (EPA) has finalized its ENERGY STAR® version 7 Display program requirements, establishing new efficiency performance levels for computer monitors and signage displays. According to the EPA, version 7 requirements will result in savings of over $130M annually while reducing greenhouse gas emissions equivalent to 225K automobiles.

An electronic display is defined as a product with that provides visual information from a computer, workstation, or server using one or more inputs (i.e. VGA, DVI, HDMI, USB), external storage (i.e. flash drive, memory card), or a network connection. Digital picture frames, electronic readers, and products with integrated television tuners are excluded.

Electronic displays are separated into two groups:

  • Monitor: A display intended for desk based viewing by one person
  • Signage Display: A display used in non-desk based viewing, intended for multiple person viewing (i.e. restaurants, stores, airports). To be classified as a signage display, the product must meet at least two of the following:
    • Diagonal screen size > 30 inches
    • Maximum reported luminance > 400 candelas per m2
    • Pixel density ≤ 5,000 pixels per in2
    • Ships without a mounting stand

Monitors: With version 7, the EPA has switched to a Typical Energy Consumption (TEC) approach, limiting annual energy consumption. A monitor’s TEC is calculated using the following equation:

ETEC = 8.76 x (0.35 x PON + 0.65 x PSLEEP)

Where: ETEC = annual total energy consumption (kWh), PON = measured on-mode power (W), PSLEEP = measured sleep-mode power (W)

To be compliant, ETEC must be ≤ ETEC_MAX plus any applicable adders as shown below:

ETEC ≤ (ETEC_MAX + EEP + EABC + EN + EOS + ET) × eff AC_DC

Where: ETEC_MAX = base energy limit calculated using Table 1 below, EEP = enhanced performance display allowance (kWh - see spec for details), EABC = automatic brightness control allowance (kWh - see spec for details), EN = full network connectivity allowance (2.9 kWh), EOS = occupancy sensor allowance (1.7 kWh), ET = touch screen technology allowance (kWh - see spec for details), effAC_DC = power conversion adjustment (1 for AC-powered and 0.85 for dc-powered displays)

Table 1. ETEC_MAX Calculation for Monitors

Area (in2)ETEC_MAX (kWh)
Where: A = viewable screen area in in2 , r = screen resolution in megapixels
A < 130 (6.13 × r) + (0.06 × A) + 9
130 ≤ A <150 (6.13 × r) + (0.69 × A) - 72.38
150 ≤ A <180 (6.13 × r) + (0.21 × A) – 0.50
180 ≤ A <200 (6.13 × r) + (0.05 × A) + 28
200 ≤ A <230 (6.13 × r) + (0.03 × A) + 31.33
230 ≤ A <280 (6.13 × r) + (0.2 × A) - 7
280 ≤ A <300 (6.13 × r) + 49
300 ≤ A <500 (6.13 × r) + (0.2 × A) - 11
A <500 (6.13 × r) + 89

 

Signage displays: A modal approach continues for signage energy efficiency, regulating power consumption in active and standby modes of operation. The display’s measured on-mode power consumption (PON) must comply with the following requirement:

PON ≤ PON_MAX + PABC

Where: PON_MAX = maximum on-mode power (W) and PABC = power allowance for displays with Automatic Brightness Control (W)

PON_MAX and PABC are calculated using the following equations:

PON_MAX = (4.0 × 10-5 × ℓ × A) + 119 × tanh (0.0008 × (A – 200.0) + 0.11) + 6

Where: PON_MAX = maximum on-mode power (W), ℓ = display’s maximum measured luminance (candelas per meter2), A = screen area (in2), and tanh = hyperbolic tangent function

PABC = 0.05 × PON_MAX

In addition to on-mode power, sleep-mode power (PSLEEP) consumption must meet the following limit:

PSLEEP ≤ PSLEEP_MAX + PN + POS + PT

Where: PSLEEP_MAX = maximum sleep-mode power requirement (0.5 W), PN is the full network connectivity allowance (3 W), POS is the occupancy sensor allowance (0.3 W), and PT is the touch screen allowance (1.5 W for screens > 30 inches)

The effective date for ENERGY STAR Display specification version 7.0 is July 1, 2016. For more information, visit the ENERGY STAR Display Program web page.