Lighting control systems open the door to major flexibility, energy-saving and sustainability benefits – but where do you start when specifying one. Stephen Woodnutt of Delmatic explains
In the early days of lighting controls, systems were normally installed only in large commercial headquarters where clients could afford the benefits of this “new” technology.
Since then much has changed, and now that some degree of lighting control is mandatory to meet the requirements of Building Regulations, designers and contractors need to be able to select the most appropriate level of control to suit the project requirements.
Lighting controls do, of course, range from the simplest stand-alone presence detectors to the most advanced intelligent lighting management systems which individually address, manage and monitor every light fitting.
Not surprisingly, the benefits you get are related to the flexibility and sophistication of the controls, so systems with presence detection and daylight-linking score highly, while maximum savings come from systems which integrate services such as lighting and air-conditioning.
So what level of controls would you install and where do you start when designing a system ? Do you need control of individual fittings or wired groups of fittings, do you need switching or dimming, and what about local user controls ?
The challenge for the specifier is to select the most appropriate control system and strategy in the context of building usage and budget, bearing in mind that requirements differ within the various areas of the building. Shell and core areas do not need a high degree of flexibility, yet office areas certainly do if they are to be able to adapt to changing requirements over the lifetime of a building.
Other considerations are the electrical installation approach and the ceiling structure. Busbar trunking and chilled beam installations typically point to Dali buswire solutions where you can control and monitor individual fittings along a common buswire: projects with suspended ceilings mostly use a plug-in switching or Dali approach which speeds installation and avoids on-site addressing of the ballasts.
The Shard in London – soon to be the tallest building in Western Europe – is a good case-in-point of applying different strategies to different areas. Dali controls are used throughout the building – within offices, corridors, lobbies, staircases and toilets – and yet the technology is applied in a way which best matches the control flexibility required with the preferred method of electrical installation. And although the system application in each area is different, all areas are managed and monitored from a head-end PC.
Emergency lighting too is centrally monitored and tested with the means of monitoring, again, different within each area. Dali intelligent emergency packs, Dali photocell monitoring devices and Dali photocell monitoring devices were selected to suit the light sources in an area yet all of them are centrally monitored through the head-end PC.
To really optimise energy efficiency, we should be looking at integrating building services through open systems. In our homes we turn the lights off and the heating down when we are not there – so why not too in our commercial and other buildings?
A common feature of lighting management is the inclusion of presence detection to relate lighting to occupancy: how much better then to also link air-conditioning and heating to occupation – if possible using the same sensor! This brings us to open, integrated systems.
Open integrated systems can, through their ability to interact with other systems in a building, deliver significant savings in energy consumption as well as comfort to occupants.
A lighting management system multisensor in an integrated system solution controls not only lighting in relation to occupancy and daylight, but also adjusts the fan-coil or VAV unit speed according to presence or absence, sets the temperature band to a wider settiung in unoccupied periods (and every degree of temperatrue saved achieves 4% energy savings) and can adust solar shading according to the multisensor readings: in addition, small power can be related to occupancy.
Open systems bring other benefits too. Using a proprietary system from a single manufacturer carries the risk that the manufacturer will withdraw support in the future: open systems free clients from relliance on a single supplier.
We have seen that open, integrated systems can achieve enhanced energy efficiency and therefore provide operational savings throughout the lifetime of a building. But surely, you say, integrated systems are more expensive than proprietary systems?
If you simply look at each system as a stand-alone entity there is the appearance of higher cost, but an integrated solution can’t be evaluated piecemeal. In fact, when you consider the bigger picture and take account of the reduced purchase and installation costs achieved by, for example, sharing the same buswire and a common sensor, the picture is very different.
To put this in perspective it’s worth considering a case study carried out by quantity surveyors Turner and Townsend and consultants BWP. They designed and costed an 11,000 sq.metre Virtual Headquarters building, comparing the cost of services installation using proprietary systems with the installed cost of an open system. The study concluded that the open protocol, integrated solution achieved a saving of more than 4% per square meter.
And, in these straightened times, when every penny counts more than ever, isn’t it time we worked together to design more integrated, open solutions which save our money and environment, both now and in the future.
