Directive Decoder

The main aim of the directive is to reduce the energy consumption of electrical equipment, especially while in use. However, any environmental impact such as the use of hazardous substances and ease of recycling could also be legislated. The directive itself sets a list of criteria that need to be met if an implementing measure is to be permitted. There has to be at least 200,000 units sold per year of a given product although the directive does not specify whether this is of individual product types or broad categories.

There must be significant potential for environmental improvement but without serious cost to industry or consumers. It is the responsibility of the European Commission to carry out studies to determine if implementing measures are required and to recommend targets such as energy consumption reductions for industry to reach. So far there have been over 20 studies into different product types and many more will be carried out in the future.

Studies underway include:
• External power supplies and battery chargers (this is complete)
• Stand-by and off-mode power losses
• Personal computers
• Consumer electronics – televisions
• Office lighting
• Street lighting (this is complete)
• Set top boxes
• Electric motors 1 – 150kW
The first two of these are generic covering a wide variety of product types whereas the others target specific products or components. The recommendations from the two studies that are complete are useful to illustrate the type of requirements that will be required for all products although it should be noted that studies provide options, they do not make recommendations.

External power supplies and battery chargers
This study identified the best available technology that is in current use as well as new developments that will be available in the near future. It is likely that implementing measures will force designers to utilise new low energy technologies. These include:
• Switch-mode power conversion
• Integrated ICs
• Efficient transistors such as MOSFETS
• Resonant switching
• Synchronous power rectification

Designs will also need to have low power consumption when not under load. Nokia for example plan to develop a battery charger that tells the user to unplug it when not in use.
Street lighting
The conclusions from this study concentrate on the types of lamp that provide the best energy efficiency, but ballast efficiency and luminaire design are also considered.

Obligations on designers
The approach that the European Commission and Parliament will use is to legislate if voluntary eco-design improvements are not already in place and seen to be effective. It is therefore in the interest of manufacturers and their design engineers to plan ahead by designing all new products with the environment in mind as this will provide products that comply with future voluntary or compulsory requirements. It will be worthwhile considering, as a high priority in future products their eco-design and in particular energy efficiency. There are many things that designers can do to reduce energy consumption in use as well as innovative approaches such as the Nokia battery charger.

Some ideas include:

• Design equipment with good ventilation and low power dissipation components to avoid the need for fans. Fans consume significant amounts of power
• The power consumption of ICs and other components (motors, motor controllers, transformers, etc.) varies considerably although the information is often hidden in lengthy datasheets. Choose low power consumption components
• Use lower voltages. Power consumption is directly proportional to voltage and so halving voltage halves power consumption
• Use active power management to switch off systems and functions that are not in use. Battery life of mobile phones and laptop computers has been greatly increased by this approach
• Minimise the number of supply rails in a product as well as using low voltages
• Use LCD instead of CRT displays. LCDs also use less power than LED indicators or filament lamps.
• Use switch mode power supplies instead of linear power supplies

Low power designs can have other benefits, reliability tends to be better and the life of components, such as electrolytic capacitors, will be longer if the operating temperature is lower.

Eco-design is not only about energy consumption and although this is the current priority, all aspects of design should be considered. Avoiding hazardous substances if possible, difficult to recycle materials (also encouraged by the WEEE directive) and rare metals such as gold that use huge amounts of energy to extract and use very toxic substances to refine (cyanide) is always advisable.

Impact on the Design Engineer:
• May need to comply with implementing measures
• Should pre-empt future measures in new designs
• Consider energy consumption of new designs as higher priority that previously. Also avoid hazardous substances where possible
• Compliance documentation may be required for some products

Directive Decorder