There is still confusion and continuing debate over the Energy Performance of Buildings Directive, the European edict designed to bring about increased investment in energy efficiency measures in buildings. The timescale of implementation, methods of energy use calculation, type of certification required, how the rules will be enforced … none of these factors seem to be set in stone yet, at least in the UK.
However, the construction of new buildings, and the refurbishment of existing ones, will not wait for the planners and legislators to dot the ‘i’s and cross the ‘t’s of the new directive. Architects, designers and specifiers need to ensure they are already incorporating sustainable and energy efficient equipment and systems into current projects that will help meet the obligations imposed by the new directive.
The correct use and control of lighting will play a very significant role indeed in helping building owners and users meet their energy saving responsibilities under the directive. Before taking a detailed look at the contribution lighting can make, let us set the scene for the Energy Performance of Buildings Directive. First published by European legislators in 2003, its intention is to greatly increase awareness of the amount of energy that is expended during the day-to-day use of commercial buildings such as offices. There are 160 million buildings in the European Union and between them they use 40% of Europe’s total energy consumption, and are responsible for 40% of Europe’s carbon dioxide emissions.
Under the new directive, a calculation of overall energy use will have to be made for every commercial building. The calculation will cover space heating and cooling, ventilation, hot water and lighting. Far too often, lighting is the last thing to be considered when identifying both energy waste and opportunities for saving energy. However lighting actually accounts for up to 25% of all emissions from commercial buildings.
In the UK the implementation of the new directive will be via Part L of the Building Regulations which covers the conservation of fuel and power; revisions to Part L were published in April 2006.
Part L states that lighting controls for general lighting in all types of spaces “should be provided so as to avoid unnecessary lighting during the times when daylight levels are adequate, or when spaces are unoccupied.”
So if unnecessary use of lighting can be eliminated, and the maximum use can made of natural lighting levels to offset electric lighting, then any commercial building can be on target to meeting a quarter of its energy saving obligations, before ‘big ticket’ energy items like heating and air conditioning need even be considered.
The Energy Performance of Buildings Directive says a methodology needs to be in place which calculates the energy performance of buildings. This must include information about every built-in lighting installation. It also says the positive influence of natural lighting must be taken into account in this calculation.
What considerations should the architects, designers and specifiers take into account in current newbuild and refurbishment schemes to ensure that lighting makes a real impact into these Energy Performance of Buildings Directive calculations? Obviously the specification of the latest low-energy luminaires, such as LG3-compliant T5 luminaires, is vital. These feature thinner tubes and efficient reflectors which concentrate the light output to the working plane. They are more efficient than older types and deliver a higher light output, so significantly cutting the amount of electricity needed to provide a given level of illuminance.
But the most energy efficient luminaire of them all is the one that is switched off when it is not needed. Automatic lighting management and control systems are specifically designed to switch off or dim individual lights, or designated lit zones, whenever levels of natural light are sufficiently high, or because occupants have vacated the monitored area.
Various types of lighting control systems are available, ranging from basic timer-based systems to complicated methods involving lighting control integrated with Building Management Systems.
The light fittings themselves are controlled automatically Light fittings, by their nature, represent a large number of small loads, distributed through the whole building. Lighting controls, therefore, need to be both cost effective and discrete. Lighting controls from Ex-Or Ltd use a variety of detection technologies – passive infrared, microwave, ultrasonic – to continuously monitor the working areas and detect the slightest movements that signify occupants are present. Photocells are built in to measure the amount of natural light available and tell the luminaires whether or not to switch on, and at what levels of brightness. These combined presence detection/photocell devices are delivering proven performance in office and commercial buildings up and down the country, often controlling areas such as corridors, stock rooms and meeting rooms. Energy savings of 40% to 60% are usually made in typical office applications.
For integrated and intelligent building-wide lighting control, a managed lighting system offers the most efficient, cost-effective and installer-friendly solution. A managed lighting system, such as the Ex-Or MLS Managed Lighting System, allows groups of luminaires to be individually controlled in pre-determined work zones, in an open-plan office for example. Detectors associated with luminaires are capable of swapping occupancy information with others within the building – useful for delivering the correct level of lighting to occupants in work zones and holding lights on automatically in key circulation areas and corridor routes. Think of it as creating the ability for an entire building’s lighting system to think for itself and make intelligent decisions about the optimum delivery of light.
A managed lighting system can be further enhanced, for example by incorporating a scene-selection capability whereby occupants can choose – at the touch of a button – previously set lighting scenes to best suit the current use of the room. A lighting scene in an office could be brightly lit for office cleaning, then lit at a low level for an AV presentation, for example.
Simplicity, ease of use and reliability should be the watchwords of lighting management and control. In an ideal situation, building users should not even be aware that a lighting control system is in operation because lighting levels are automatically set at the optimum level.
It is clear, therefore, that automatic lighting control can deliver real energy savings and a significant push along the road to meeting Energy Performance of Buildings Directive obligations.
But let us not lose sight of the fact that automatic lighting control already guarantees compliance to other legislation which is on the statute books now – including Building Regulations, Health and Safety legislation and Display Screen Equipment Regulations.
Remember, too, that commercial buildings that rely too heavily on artificial light and do not take advantage of existing levels of ambient light can impact in a negative way on the productivity and performance of people working within the building. Automatic lighting control delivers the most productive lit environment for occupants. Most organisations recognise that ultimately their employees represent the largest proportion of total building running costs, so even small increases in employee productivity can significantly enhance their bottom line.