Energy Figures of the Month

Energy Figures of the Month

Regulators put the heat on ice maker efficiency

Ice makers waste a lot of energy, and the Dept. of Energy isn't happy about it. So look for new efficiency standards to begin in 2014. In tests of four different refrigerators, scientists from the National Institute of Standards and Technology (NIST) found that ice makers boosted energy consumption by 12 to 20%, due mostly to electric heaters used to release ice from molds. Because refrigerators account for 8% of the total energy consumed by 111 million U.S. households, the potential savings from more efficient ice makers are significant. The DOE says it will raise the minimum efficiency standard by 25% over the current level, starting in 2014.

Source: NIST Technical Note 1697, April 2011

More affordable LED lighting

Impressive light quality and efficiency aside, LEDs are still too expensive for widespread use. However, look for costs to drop substantially over the next few years. So predicts the DOE's Solid State Lighting (SSL) Multiyear Program Plan and the cost reductions it projects. Projections factor in cost savings from better manufacturing processes and from luminaires “designed for manufacture,” which would most directly impact thermal and metal bending expenses. Significant savings will also come as manufacturers automate what are now manual assembly tasks. The DOE figures annual cost reductions will be about 20%, representing a price drop by a factor of about three in 2015 and about 35 by 2025.

Source: Solid-State Lighting Research and Development: Manufacturing Roadmap, Sept. 2009

Research points to ideal spacing of wind turbines

What's the most efficient way to position wind turbines so they'll convert moving air into power most efficiently? Charles Meneveau, a Johns Hopkins fluid mechanics and turbulence expert, working with a colleague in Belgium, has devised a formula that helps answer this question. In a nutshell: Farther apart is better. Today's wind farms typically use turbines with rotor diameters of about 300 ft, with turbines spaced about seven rotor diameters apart. The new spacing model suggests that placing turbines 15 rotor diameters apart results in significantly more economical power generation.

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