Good lighting control prevents energy wastage

Paul Boughton

Using the latest lighting control technology to cut energy bills can save engineering industries significant unnecessary expenditure. Dr Andy Davies, brings us up to date on the latest developments.

The International Energy Agency has reported that the installation of energy efficient lighting systems across the world could cut global energy consumption by as much as 10 per cent, providing opportunities for financial savings. Lighting is, on average, responsible for as much as 40 per cent of electricity costs in offices and 50 - 60 per cent in factories and warehouses.

Of course, lighting is not only heavy on the pocket but also has a major impact on the environment. The amount of carbon dioxide produced globally from generating electricity for lighting is three times higher than the emissions produced by aviation. With carbon dioxide the largest of the trace gases and currently responsible for 60 per cent of the 'enhanced greenhouse effect', anything that contributes to lowering this figure is welcome.

Recent advances in LED technology have led to more sophisticated lighting control solutions being available than ever before. The inherent controllability of LEDs - being easy to dim and instantly switchable - offers significant opportunities for energy savings. Dimming lights, for instance, saves energy even though the difference in, say, a lux level of 100 per cent and 90 per cent is usually imperceptible to the human eye.

Installing new lighting technologies, together with lighting controls, can result in savings of over 50 per cent in terms of energy consumption and cost, which is likely to lead to a dramatic growth in the lighting controls market. Industry analysts expect this sector to more than double by 2020.

Technologies and control strategies

Lighting control systems can typically be divided into two categories: those that are integrated with Building Automation Systems (BAS) and those that are dedicated lighting systems such as DALI or Analogue 1-10V control for dimming. A growing trend towards complete building automation, however, means that even standalone systems can now be connected to the BAS via a gateway device.

The most common strategies for lighting control installations are:

- Daylight harvesting, where natural daylight is used to contribute to the lighting in the building and lights are dimmed accordingly based on measurements from photocell sensors;

- Occupancy, where lighting is dimmed or switched off when no one is there, or switched on or made brighter when a space is occupied;

- Time scheduling, where lighting schedules are programmed to switch and dim at set times, usually by zone, floor or room;

- Scene setting, where different lighting scenarios are used to suit the activity taking place at a particular time, saving energy from unnecessary lighting. For instance, a greater intensity of light will be required for some engineering processes than is required for cleaning.

Often, several of these strategies are employed at the same time although this brings challenges in optimising the configuration of the control system. Configuring the control system can be complex and time-consuming, usually requiring a specialist engineer to carry it out. Typical costs of DALI engineers in the UK range from £600 - £1000 per day.

A further key drawback to current lighting control solutions is the difficulty of fitting them into existing installations. Many businesses have identified the advantage of installing high efficacy LED fixtures to replace older generation halogen, fluorescent and metal halide lighting in their facilities. The LED technology used is controllable, but the installation of a suitable control system is prohibitive in these scenarios due to the cost of rewiring and the disruption to operations that this would inevitably cause.

A new report from the International Energy Agency (August 2013) recognises that much of the future building stock in its 28 member countries is already in place and that the main challenge is to renovate existing building stock to reduce the demand on energy. The Royal Institution of Chartered Surveyors reports that the Sustainable Building Certification statistics in Europe leave much room for improvement, partly due to the fact that processes within existing buildings cannot be as easily 'steered' as in new build.

Harvard Engineering has addressed these challenges with new technologies adapted from its award-winning LeafNut street lighting systems. A new product, due to be launched in November, will apply the same unique lighting control technology used in lighting our streets and motorways, to indoor lighting - a wireless networked control system which incorporates data monitoring and analysis to optimise the energy-saving potential of any given lighting system.

Wireless networked control

This new technology, EyeNut, can be applied in both new build and retrofit situations and eliminates the need for expensive, complicated re-wiring. Another important advantage of the system is that operators will be able to manage lights remotely from a computer, providing the exciting possibility of multiple-site or indeed multiple-building control from a single hub. The system uses the secure open protocol Zigbee mesh network.

Zigbee is designed for low data rate, low-power applications and provides robust protection against communication breakdown between two devices on the network. A Zigbee network-enabled LED driver is small, compact and presents no additional installation challenges.

The technology is completely customisable, allowing the user to fully adapt individual lights or groups of lights to match changing requirements at the press of a button. A mapping feature gives the user a complete view of all light points set over an imported image of their building layout.

Data monitoring and analysis

All of these aspects are controlled via an intuitive Graphic User Interface (GUI). The GUI allows operators to monitor the performance of individual, or groups of luminaires, while also collecting energy consumption details, see the dim status of each light, and accurately predict lamp failure. This not only allows quick decisions to be made about system performance and usage parameters, but data can also be analysed, to optimise the performance of the interior lighting and streamline maintenance.

This system can integrate with existing Building Management Systems to collect occupancy data and any other relevant information, to determine whether the lighting is being used in the most efficient way.

In summary, LED lighting technology continues to evolve to provide a better, brighter quality of light to improve our working environments and reduce energy expenditure. With this comes a new generation of lighting control to contribute further energy savings. For this to be fully realised, the new technology must be capable of being retrofitted into existing buildings as well as installed in new ones. Data monitoring and analysis are also crucial in order to make the best possible use of these controls. Accurate accounts of energy expenditure give users complete control over their lighting expenditure and the flexibility to make changes accordingly.

The potential for savings in the engineering industry, as in others, is huge. Of all the controllable lighting sold in Europe today, 75 per cent is not currently being controlled by anything other than the on/off switch. It's time to make a change.

Dr Andy Davies is business development manager for indoor controls at Harvard Engineering, Wakefield, West Yorkshire, UK.