Lighting Controls – ‘From energy conservation to lighting solutions – and back’

Lighting controls in the commercial building market have largely developed from systems designed in the late 1970s to reduce energy consumption. In the late '80s the market changed dramatically with the emphasis turning to rapid installation and high flexibility - and sometimes energy saving was forgotten.

This was the time when the 'plug-in' lighting control module took off establishing a new standard in fast and flexible lighting installations. Unfortunately such solutions could only deliver energy savings if they accepted local overrides and could be fitted out to match the needs of the individual users. When attempts were made to reduce costs still further by using 'plug-in' modules with no control functions - dumb marshalling boxes - then energy savings left the building.

A modern example:

Fortunately, clients are now demanding additional features and benefits including scene setting, comfort, safety and data logging, when they specify a lighting management system. The Royal Bank of Scotland's new HQ in Gogarburn is a fine example of the breadth of control and monitoring abilities now required for such applications.

The overall concept for the new RBS HQ is a self contained business community with offices, restaurants, shops, leisure facilities, and conference centres and more. Depending on the needs of each of these areas, the lighting control system provides a variety of functions - from basic on/off occupancy detection to promote energy saving, through to advanced scene setting programmes that offer comfort and effect. This clearly illustrates the demand for today's lighting control systems to offer much broader abilities that must include energy saving, low cost installation, real flexibility and ease of use. In this application, the reduction in energy use will be at least 30% when compared with a conventional installation - a result that reflects the Royal Bank of Scotland's environmental policy to use energy efficient and sustainable solutions.

Energy saving back on the agenda:

Today energy saving has returned to the agenda - electricity prices are rising again but, more importantly, businesses are more conscious of their corporate responsibility and need to be 'green'. To this end they will frequently use the Building Research Establishment's Environmental Assessment Method (BREEAM) to define the required energy performance of their planned buildings. One such organisation - the Met Office - achieved an 'excellent' rating assisted by the inclusion of controls within the overall lighting solution. In addition to matching the lighting in use to the available daylight and the numbers of staff present, the Philips Lighting LightMaster Modular system also tests and monitors the emergency lighting, further reducing the overall cost of ownership.

So how are today's lighting controls delivering energy savings while still maintaining good lighting design criteria and providing a comfortable working environment? Products like LightMaster Modular provide an interactive, networked solution that can be set up to manage the installed lighting without compromising the design intent. Luminaire outputs can be set to provide the correct illumination from day one, and sensors can ensure that daylight is properly taken into account, and that no unnecessary lighting levels are maintained in unoccupied areas. Even the need to maintain background and comfort lighting (as recommended in EN12464) can be programmed into the system and tailored to prevent any waste. But it is not just the control system that delivers these results. The advances made in both lamp and gear technology meant that today, when you apply 'scene setting' to a fluorescent lighting scheme, whenever you dim the lights you will be making real energy savings. Not only is the power in / light out close to a straight line, but the base load of the gear itself is also being reduced with the latest HF-D electronic gear and T5 lamps. This is a real win/win situation. In addition, this technology is now being migrated towards other light sources.

DALI and more:

Intelligence and functionality are now effectively moving towards the lamps and the sensors, as witnessed by the digital addressable lighting interface (DALI) which gives ballasts both an address and dimming capabilities that used to be part of the control system. Internal light sensors are now more easily calibrated with the press of a single button, as well as being better at informing the attached system about the local ambient lighting conditions. Much time and research has been spent on getting the latter right by using carefully designed 'windows' and filters that are solely dedicated to this task.

In recognising these technology trends, tomorrow's lighting management systems will become much more versatile. Their functionality will be adaptable from pure energy saving right through to the control of dynamic lighting effects involving colour, mood, speed and intensity - all provided from a single, seamless platform. Such systems will no longer have to compromise between one objective or another, even though the spotlight is once again turning to energy savings. The twin drivers of legislation (there will be a new edition of Approved Document L published early in 2006) and much higher energy prices will effectively push people towards the purchase of the most energy efficient lighting solutions.

The only irony of this situation is the fact that we have known for a long time that it was never really necessary to compromise a lighting management system. Even in the early 1980s it was clearly identified, in the various Demonstration Projects being monitored for their energy savings, that people in workplaces were much happier when they were allowed to control their own local lighting levels. More recently the extended study by Slater, Carter and Moore showed that this research remained true, when they found that in the several buildings they were examining, the environments reported as most comfortable were also the most energy efficient.

Now that we are being asked to provide energy savings again it seems that we have come full circle but maybe it is a 'virtuous circle' now! Because when a lighting installation is designed today, every component - lamps, gear, optics and controls - will be working together to give both high quality illumination and a low cost of ownership. Moreover, it is to be hoped, with the evidence already established, the legislation in place, and there being no need to compromise between energy saving and effect, it will no longer be necessary to waste time doing payback calculations.

The picture shows the Royal Bank of Scotland HQ at Gogarburn.