LED technology will play an increasingly important role in lighting technology in the future, because it has the potential for less carbon dioxide emissions, lower costs and a better quality of light.
Which segments have been appraised by Siteco as being especially promising for LEDs, how Siteco regards the future, what is to be found in the pipeline and to which work groups Siteco is contributing with regard to the further development of LEDs and OLEDs can be read here in an interview with Ingo Susemihl (Head of Sales and Marketing) and Michael Härtl (Head of Research).

1a) For which application segments does Siteco currently offer LED luminaires? Which priorities does Siteco set with the development of LED luminaires?

Susemihl: In the outdoor sector Siteco focuses upon technical road luminaires and decorative mast luminaires for town and park lighting. Building vicinity lighting (facade illumination) also plays an important role.
But specifically: both the classic, proven town and park luminaires (Mushroom, Lantern, City Light) as well as the DL500 Mini, SQ 50 and SR 50 road luminaires are immediately available as LED variants. In addition we are also presenting technical and decorative LED outdoor luminaires with completely new design approaches at Light+Building 2010.

For the indoor sector, Siteco has focused upon point light sources (downlights) for applications in public spaces (corridor areas, foyers) and also office lighting as well as the shopping sector for accentuating lighting. LED is gaining more importance with wide-area illumination for office lighting and with linear, compact LED luminaires for linear configurations in public areas and industry. For the office sector Siteco offers for example the Quadrature® 2 luminaire family with LED lighting technology for general lighting purposes. Siteco also sees potential with special lighting demands such as in cool ambient conditions.

1b) Which application segment according to Siteco is the most promising?
 
Susemihl: The attractiveness of application segments depends upon various factors:
• The use of LED technology is of interest where long burning periods are characteristic, for example with road lighting and the illumination of corridors.

• The attractiveness is also dependent upon the size of the lumen package required in order to fulfil the lighting task.
Because the lumen packages are lamp-dependent, the question of which lamp type is to be replaced by LED must first be answered. In road lighting, 50W, 70W, 100W, 150W and 250W  high pressure sodium vapour lamps (HST), the most economic method of producing light until now, can already today be meaningfully replaced by LED (assuming that lighting technology and luminaire technology are optimised for the use of LED). HST lamps with wattage of 400W and greater are used nowadays in road lighting mainly for niche applications. Due to high thermal loads and the lumen costs of LED solutions, such applications will continue to be operated with conventional lamp technology.

• LEDs are always promising where special demands are placed on the lighting solution, for example where light is to be used for in-scene setting. The control possibilities and the colour mixing of LEDs make them especially suitable for presenting as well as for dynamic, coloured lighting design, both for indoor and outdoor spaces (including facade illumination). Where properties such as continuous dimming and highly saturated colours (without the requirement for a supplementary filter) are of importance, LEDs are also a suitable light source.

From the point of view of dimming and control, for Siteco there is particularly interesting potential for road lighting. Here enormous possibilities for saving come about in terms of energy consumption. Already today with respect to cost efficiency and energy we are able to save up to three quarters of energy consumption in comparison with conventional mercury vapour lamps. In many European countries, around one third of light points in outdoor applications are still equipped with these inefficient lamps.

LED technology is also an optimal alternative to metal halide lamps (HIT), because:
• LEDs have a good luminous efficacy that is continuously improving (over 100 lm/W for the foreseeable future)
• LEDs convince with a long service life (up to 50,000 hours and more depending upon temperature and luminaire)
• LEDs have good colour rendition
• LEDs are especially suitable for use with low ambient temperatures such as found in outdoor applications (particularly Northern Europe or nocturnal operation for example)

With the implementation of the new technology towards successful products, Siteco has the advantages of wide-ranging expertise in the areas of lighting technology (optimal light control), luminaire technology (thermal management) and control technology (savings via the optimal use of additional control features).

1c) Which sector was the most important contributor to turnover until now, and where are the largest expansions expected?

Susemihl: Already today significant turnover is achieved with LED luminaires, and mainly in the road lighting sector. Siteco offers two approaches with LED solutions here:
• 'Retrofit' modules based on gear trays as a substitute for conventional lamps in existing luminaire housings (e.g. Module 520).
• LED luminaires where in ideal cases the complete luminaire is optimised for LEDs to create a perfect symbiosis between energy efficiency and lighting task (for example Streetlight 10 mini and midi).
LED technology is also popular though for decorative applications and indoors as well, for example with downlights, or in cool ambient conditions such as for cold stores and freezers. The significance of this new technology is increasing rapidly and in the meantime now represents the fastest-growing segment. As such, we have oriented our product developments and launches consistently towards LED and now offer lighting solutions with LED for all essential application sectors.

1d) Should new (application) sectors be tapped?

Susemihl: With the steep increase in luminous efficacy, most application sectors that could until now only be served with conventional technologies will also be realised with LED solutions. New application areas for Siteco could for example be:
• A thrust into the classic area of general lighting
• Lighting applications that require a special form, e.g. in areas with limited space (cove lighting)
• Presentation with light (colour chases with LED, facade architainment)
• Industrial lighting
• Retail areas

 
2. In which areas will LEDs predominantly replace conventional lamps?

Härtl: LEDs will assert themselves the most where their advantages, meaning their use in application, bear greatest validity, i.e. where the following factors are applicable:
• Energy efficiency
• Maintenance costs
• Form design
• Possibilities for dynamic control

The rate and extent of such replacements depends upon actual benefits for the application. In principle it can be said that with regard to efficiency improvements, applications with relatively low ambient temperatures (outdoors, cold stores) are more attractive than those in warm environments. Furthermore, with LED luminaires the customer in a sense pays for each 'lumen', and so luminaires with lower wattages are more likely to be substituted than those with higher wattages. In areas where operational energy is not sourced from the general electricity network but for example from battery sources (with emergency lighting for example), LEDs have already asserted themselves.

3. Can trends be seen in luminaire development and engineering that
a) take account of the long service life of LEDs, or
b) enable later replacement of an LED module with a newer, more efficient one?

Härtl: a) That depends significantly upon how long the typical utilisation time of a luminaire in its application is. While road luminaires achieve economic service lives of over 30 years, there are indoor applications where luminaires are regularly replaced every five years. Here the service life of the light source corresponds to that of the luminaire, thus opening up the way for example for new conceptional luminaire constructions.

b) For applications where the luminaire service life is greater than the LED service life, Siteco has already drawn up replacement concepts for the LED module.
The key to this sustainability is found in Siteco LED gear tray technology: light sources, optics, thermal management and control gear are all accommodated by a central module (Module 520 for Siteco town and park luminaires such as the Mushroom and Lantern). Simultaneously this construction ensures that future, more efficient LED generations can be easily retrofitted, or that existing luminaire systems featuring conventional lamps can be modernised according to the latest state of technology.
 

4. Do the many LED retrofit solutions perhaps hinder the market entry of innovative, new luminaire designs based on LED technology?

Susemihl: Firstly we have to differentiate between two procedures with the retrofitting of conventional lamp technology to LED technology:
• The replacement of standard lamps and standard sockets to LED socket lamps (LED retrofit lamps)
• The use of a retrofit module, meaning the replacement of a gear tray in an existing luminaire (LED retrofit modules)

The second variation is used with Siteco outdoor luminaires.
Siteco LED gear tray technology enables light sources, optics and control gear to be accommodated by a central module. In this way existing systems with conventional lamps can be upgraded to the latest technological standards. Siteco for example offers such a solution with the Module 520 for decorative town and park luminaires.
For outdoor sectors, the LED retrofit modules and the new innovative LED luminaires with sophisticated designs complement each other ideally in the market. Retrofit modules are applied as energy-efficient lighting solutions in existing old systems, especially with classic town and road luminaires with more traditional designs, as well as with system expansions with a view to maintaining the urban ambience and appearance. LED outdoor luminaires with new design approaches are intended for modern, future-oriented town and street landscapes with their optimised technology and maximum potential for energy savings.

For the indoor sector there are diverse LED retrofit lamps available as replacements for fluorescent lamps for example. Surveys have shown that such solutions are often insufficient in terms of lighting technology and energy aspects.
Siteco attaches importance to the development of its own, energy efficient luminaire concepts for indoor areas, such as the Quadrature® 2 LED office luminaire shown for the first time at Light+Building.

5. Does the use of LED luminaires bring with it greater implementation of lighting control?

Härtl: Yes. Compared to conventional light sources, LEDs offer outstanding possibilities for 'wear-free' switching and dimming. As such, applications with which a luminaire is controlled via a sensor for example will become more popular with the advance of LEDs.

With the Service Box, Siteco offers a parameterising device that can adapt the functions of the Siteco LED outdoor luminaires and optimise these according to their actual lighting tasks. In addition complete software files such as colour sequences with the DL10 can be transferred to the luminaire. Following parameterising, the Service Box is then removed again. Customers are able to achieve maximum cost and energy savings with the optimisation of settings for Siteco LED outdoor luminaires according to their specific project requirements, without the need to invest in supplementary control components.
 
6a) Why do standard evaluation criteria fail with respect to the performance evaluation of LEDs in comparison with conventional light sources?
According to which criteria should the energy efficiency of LEDs be evaluated?

Susemihl: Until now it was normal to consider lumens per watt, meaning that measurements of how many lumens per watt emitted from the light sources were taken directly at the luminaire head. Merely considering the light sources is however only part of the truth.
When evaluating LEDs it is necessary to take into account the complete chain of effects. This means that with LEDs the complete system must be considered, including optics/light guiding components, control and others. Of elementary importance when evaluating LED systems is the light that is actually emitted (for example onto the road). With streetlighting for example the power consumption (W) must be put into proportion with mean luminance (cd/m²), luminaire spacing (m) and width of carriageway (m). At the end of it all it's a matter of ensuring lighting in compliance with standards with minimal KW/h per m² per year.

With the 'Street Lighting Energy Optimizer', Siteco will be offering an online calculation tool with which customers can simply and conveniently determine the most energy efficient solution for a specific type of road. (http://www.siteco.de/de/produkte/planungswerkzeuge.html)

With the evaluation of an LED lighting solution it must also be considered that the luminous efficacy of LEDs is dependent upon various factors:

• Quality of LEDs (manufacturer-dependent)
• Current feed (a higher current feed may negatively affect lumen yield and service life)
• Luminaire technology/thermal management (higher junction temperatures negatively affect the lumen yield and service life of LEDs)
• Ambient temperature (high T ambient temperatures negatively affect the lumen yield and service life of LEDs)
• Drivers (control the electrical operating parameters of the LEDs)
• Light control (LEDs, in contrast to most conventional lamps, only emit in one hemisphere. Of decisive importance for evaluation is the consideration of the optical LED system and its ability to fulfill the lighting task according to standards)

7. Which partners is Siteco currently working with? Are particular cooperations or acquisitions being planned?

Härtl: It's all about having the right cooperation partners and suppliers and being able to handle the new complexities in terms of luminaire development and manufacturing. As with many industries, Siteco has regulated the sectors of quality and delivery reliability via strategic partnerships. Siteco works together with the leading quality suppliers of LED technology and in this way benefits from being able to implement the most up-to-date, highest efficiency package.

8. Do specific initiatives exist in the industry aimed at making classification of LED sources more transparent for users? Are practical designation standards on the horizon?

Härtl: Siteco works in various bodies on national, European and global levels with the aim of specifying standards for the classification of LED luminaires and lamps. The regulatory bodies are working towards specifying aspects of safety and product quality in the sense of defining minimum requirements (such as service life, degradation behaviour, light colour and colour quality) as part of an international set of standards. The designation standards then coming about should give consumers orientation in terms of selection from the wide-ranging spectrum of products available, allowing them in turn to better differentiate between high quality and poor quality products.

9. How does Siteco see future development in the LED technology sector? Will there be a further LED technology leap? Where's it all heading to?

Susemihl: With LEDs, the semiconductor sector has entered the lighting industry. In past years it was shown in many segments that enormous further development of technical efficiency and simultaneous reduction of costs also brings on a very high level of innovation. With such furious leaps in development, those companies are particularly well positioned that are able to stay in command of innovation management. Siteco is in a good position in this respect and has always been able to make a name for itself as a technology leader in the market (Eldacon®, Mirrortec®, daylight systems etc.), and thus views LED technology as a chance.

Härtl: LEDs will be able to establish themselves further in the market according to a trade-off between taking advantage of their specific benefits in various application scenarios and the costs ensued for an LED solution. Here it must be considered that applications with lower power consumption will be more readily substituted with LEDs that those with higher lumen packages, and that niche applications will also be more readily replaced than general applications, in particular with indoor applications. Calculations such as those carried out for the new Quadrature® 2 LED office luminaire have shown that energy-efficient LED solutions for general lighting are on the horizon, especially with the use of control and luminous flux adjustments.

10. In which general regulatory boards and workgroups is Siteco involved in?

Härtl: Siteco is busy contributing to national and international boards with questions of how to maximise the benefits of LED technology. On a national association level an example is ZVEI, on a European level CELMA and internationally the IEC.

In addition, Siteco is part of the Zhaga global initiative that as an open consortium for standardisation has the aim of standardising the fundamental construction forms of LED light engines. The initiative is working to define stable form factors for the lighting industry that can be offered as being replaceable across different LED module manufacturers.

11. Which future potential is to be expected with lighting via OLEDs as a first real surface light source? What initiatives are to be found at Siteco in the area of OLED technology development?

Härtl: Siteco is seen to be one of the most innovative companies in the lighting sector. With specific product launches we always depend on mature technologies.
We consistently apply ourselves to fundamental developments in the area of OLED applications for lighting. In terms of cost-effectiveness ratios, reliability and energy efficiency, OLED technology in 2010 is not a real alternative to currently used light sources. But because of massive research investments much progress is being made in this sector, and this will lead in the years to come to commercially viable OLED components or OLED-based luminaires. Siteco for example is directly participating in this development by cooperation in the 'So-Light' research project sponsored by the Federal Ministry of Education and Research.

12. Is the lighting sector already considering the waste disposal of LED light sources or LED luminaires?

Susemihl: Siteco is participating actively in the PB5 working group of the Waste Electrical Equipment Register (EAR) towards correct disposal solutions for LEDs. The aim is integration into the scope of the 'WEEE' EU directive (Waste of Electrical and Electronic Equipment). Siteco is also active together with the Central Electrical and Electronics Association (ZVEI) in the TAG 12.8 work group for environment and disposal that concerns itself with implementation of the European WEEE directive.

13. Which guarantees are offered by Siteco for LED luminaires?

Susemihl: We of course place complete trust in the quality of our products and initially offer the guarantees that are standard in the industry. In addition though we will also be offering extended guarantees for LED products that will be defined according to specific products and applications. Further details about this are available at www.siteco.de/de/service/garantie.html

Photos: Siteco