Intelligent lights deliver more for less
14 Aug 2015
Lighting technology has seen huge innovation. We’ve seen the emergence of pioneering light sources such as LEDs and OLEDs, but also the development of intelligent control of lights. Whilst initially these controls have been implemented as external components, the logical next step is to integrate this functionality directly into the light source.
Intelligent lighting controls allow light to be automatically and individually adapted to changing situations and local requirements in real time. These controls were up to now mainly implemented as external components connected to existing lighting via defined interfaces such as 0-10V or DALI. Increasingly, however, the control functionality is integrated directly into the light source, which simplifies the replacement of existing traditional lighting by an intelligent solution.
From saving effect to legal requirements
Lighting control is becoming a focus for building designers as it is an integrated part of legal regulations. With Title 24, California set new standards for building directives. It requires, for example, that lights in unoccupied class rooms, hotels and meeting rooms automatically switch off. Such systems are required to save at least 15 percent of energy by adjusting the light level dynamically to the amount of available daylight or room occupancy, for example.
In Germany, the Energy Saving Regulation 2014 (EnEV 2014) makes the automation of building services a mandatory part of a building’s energy performance evaluation. It is the basis for a high-rated energy certificate, which affects a property’s value. The same applies to recognised green building certificates, such as LEED or BREEAM, where intelligent control contributes to valuable rating points.
In the UK finally, the EU Directive for the Energy Performance of Buildings became a vital part of building regulations in a drive for greener buildings. It aims to make energy use in buildings transparent by issuing Energy Performance Certificates (EPC) as well as identifying and developing new opportunities for a reduced carbon footprint. In addressing these new regulations, building designers need to consider which networking technology and control functionalities to use.
Labour costs and installation efforts are critical factors to take into account when planning building automation. A fast return on investment (ROI) can only be achieved if intelligent control systems can be easily retrofitted. Wireless technologies clearly have an advantage, as they are more flexible and cheaper to install than wired systems. The installation can also be expanded at any time; both with additional components as well as with more functions. Therefore, wireless technologies will benefit from the rapidly advancing success of LEDs and OLEDs and, in the long term, become the established standard.
However, there are different wireless technologies for building automation. Some standards (e.g. based on IEEE 802.15.4) use the 2.4 GHz band, a frequency approved in most countries allowing worldwide use. The 2.4 GHz band is also used by many other devices, which makes it vulnerable to interference. In addition, the range inside buildings is sometimes limited to a maximum of ten meters and can even be further reduced by certain materials such as reinforced concrete walls. Wireless solutions in this frequency band are therefore mainly suited for in-room LED control, a scenario typical for consumer lighting applications.
As an alternative to the 2.4 GHz band, some wireless technologies use frequencies below 1 GHz. These are specifically suitable for communication inside buildings as they penetrate walls and furniture easily and achieve a better range of up to 30 meters. Solutions below 1 GHz in building automation are just as reliable as wired systems as the frequencies are less crowded and therefore more robust.
Ultra-low power radio standards (e.g. ISO/IEC 14543-3-10) enable even battery less wireless solutions, which gain their energy from motion, light or temperature differences. Such sensor and switch solutions work without cables and batteries, saving maintenance effort and costs. Batteryless systems combine the flexibility of a wireless solution with the low operating cost of a wired system. With more than 1,500 interoperable products, the EnOcean energy harvesting wireless standard is already very well established in the field of building automation. For lighting control, building owners have access to a comprehensive ecosystem of different manufacturers and can integrate them into an automation system, which crosses several building areas.
Different Integration Options
In addition to different networking technologies, the system partitioning between light source, driver and control device is another crucial question on the way to smart luminaires. Currently, three main approaches are emerging:
- The intelligent control is provided by a dedicated external control device whose output is connected either via the DALI or 0-10V bus to the LED driver. Thus, multiple lights can be controlled simultaneously. The control must be installed separately
- Alternatively, there are solutions, which directly integrate the controller into the LED driver (also referred to as ballast). In a system upgrade, the existing drivers can be replaced with new intelligent LED drivers. Retrofitting is easy and can use the existing infrastructure. However, control is usually limited to the lights connected to the driver output.
- The latest trend of intelligent LED lighting integrates the control directly into the bulb or the complete luminaire. Thus, the user just needs to change the bulb or the panel in order to obtain the desired controllability. This technology is currently at an early stage in its development and is still relatively expensive. In the long term, this approach will make control as easy as changing a light bulb.
Examples of these three approaches show that each has its reason for being and can map different application scenarios.
An external controller complements the existing LED driver and can act as a gateway translating the wireless control communication to the existing lighting standard such as 1-10V or DALI. Thus, LED systems can wirelessly communicate, for example via the EnOcean radio, with batteryless occupancy sensors, light level sensors and switches to realise daylight harvesting scenarios, presence dependent control and manual dimming. Such retrofitted controllers can dim both a single LED light and zones of LED lights connected in parallel. Due to the advanced wireless connectivity of EnOcean-based systems, all parameters of lighting control can be configured using a remote commissioning PC tool. Installers can configure the controller and all components centrally and adjust lighting control to local conditions, define properties and settings, and manage and save projects. An additional gateway allows the LED controller to be integrated into a building automation system.
The second option is integrating the control directly into the LED driver. Here, an intelligent version can replace existing control units and combines both the wireless communication as well as the lighting control. If a building is retrofitted from conventional to LED lighting, the old control gear can be replaced by intelligent drivers in a single upgrade step. In contrast to the first approach, no additional external devices for radio communication are required. The lights, retrofitted in such a way, don’t need a separate control unit. In addition, the driver manufacturer can optimally adapt the controller parameters to the driver parameters. Therefore, users don’t need to separately configure this via a tool.
Finally, there is a move to integrate wireless control directly into the LED panel. Such a complete solution, also referred to as luminaire, unifies the bulbs/tubes, reflector and control electronics in one unit. Thereby, installers would implement controllable LED technology in one step by exchanging the panel. This approach can revolutionise future lighting in buildings in the context of innovative OLED technology. Thus, a shining wall would be imaginable, which automatically adapts to daylight levels or the presence of persons.
The Philips Hue LED consumer lighting system demonstrates an even more user-friendly variation. Here, intelligence is directly integrated into the bulb so that the user can easily replace old incandescent bulbs without an installer‘s help and immediately control the intelligent bulb via an app or a battery less switch. This trend is also interesting for office buildings. If existing fluorescent tubes could directly be replaced by energy-efficient LED lights with integrated control, there won’t be even the need to change the panel.
LEDs are considered as lighting technology of the future. More and more buildings are retrofitted with this new type of illumination to save as much energy as possible compared to traditional solutions. However, even efficient lighting technologies can waste energy if they are left on when not needed. Appropriate sensors and daylight harvesting technology together can make a huge impact, dimming or switching off lights in unoccupied areas or during the day when sufficient outside light is available. By integrating the control technologies into the light source or luminaire itself, the installation cost largely disappears, creating an attractive short ROI while increasing user comfort at the same time.