Light-pipes described in this paper guide light along an axis allowing it to escape from its surface for illumination purposes. Light is coupled into them by a beamer luminaire. The performance of a hollow light guide very much depends on the quality of the materials used to guide the light. The luminous characteristics of these materials influence a light-pipe’s overall performance. The first section of this paper describes measurement techniques for light incidence resolved measurements on materials. Common co-ordinate systems for describing the geometry and a data format to store the data are shown. The second section of this paper deals with light-pipe goniophotometry. A goniophotometer for light-pipes has been constructed at the Technical University of Berlin. To evaluate the results measurements are compared to these from a real installation.

Für eine zuverlässige Tageslichtplanung im Innenraum ist die genaue Kenntnis insbesondere über die bi-direktionalen Kennzahlen (räumliche Verteilung des Leuchtdichtekoeffizienten q in Abhängigkeit des Lichteinfalls) der Tageslichtsysteme unverzichtbar. Es wird eine Methode mit Beispielen (RETROLux-Tageslichtsysteme) vorgestellt, bei der die gemessenen Verteilungen des Leuchtdichtekoeffizienten konvertiert werden, so dass die Ergebnisse in konventionellen Lichtplanungstools wie DIALux oder Relux im portiert werden können, um lichttechnische Berechnungen mit photorealistischen Darstellungen durchzuführen.

No abstract

Over the last years – on national as well as on international level – integrated rating methods (daylighting as well as artificial lighting) have been developed and transferred into practice, the later was fostered by integration into the corresponding standards (DIN V 18599-4, EN 15193-1) and the methods being referenced by national regulations like the German Building Energy Conservation Ordinance (EnEV). Emerging new lighting technologies und requirements to further improve the rating procedure pushed the development of additional new efficiency figures. The concept of expense factors has long been available and applied e.g. in the domain of heating systems. Now, as derived in this publication, it is as well assigned to indoor lighting systems. Therefore, from now on, it will be possible to differentiate lighting installations by their net energy and by their final energy demand. The efficiency of the lighting system itself can be described as function of the expense factor. Currently several new LED-products (lamps and luminaires) are introduced to the market of general lighting. In order to enable practitioners to energetically rate these products, the diversity of products has been structured into classes with assigned efficiency figures. Lighting appliances strongly depend on how the considered zone is used. To provide practioners with exemplary solutions (type of lighting system, façade composition, lighting control) a collection of typical appliances as function of zone usage has been established. This collection has been matched to the structure of the German DIN V 18599 standards

Die Optimierung der Museumsbeleuchtung basiert auf der gleichzeitigen Berücksichtigung energetischer, beleuchtungstechnischer, farbmetrischer und konservatorischer Aspekte, die sich auf den ersten Blick unter Umständen widersprechen. Am Beispiel des Berliner “Bode‐Museums“ konnte gezeigt werden, dass der Ersatz der bisher verwendeten HGL‐ durch LED‐Leuchten eine Reduzierung des Energieumsatzes um bis zu 70 % ermöglicht. Im gedimmten Betrieb kann sich dieser Wert aufgrund der besser geeigneten Dimmkennlinie der LEDs noch weiter erhöhen. Gleichzeitig ist mit einer verringerten Objektschädigung durch UV‐ und kurzwellige sichtbare Strahlung und deutlich verringerter thermischer Belastung der Objekte durch IR‐Strahlung zu rechnen. Außerdem ermöglicht die Kombination verschiedener LEDs in einer Leuchte eine variable Lichtfarbe mit sehr guter Farbwiedergabe. Bei der Auswahl der LED‐Lösungen ist eine Abwägung der konservatorischen Anforderungen unerlässlich, als einfachstes Bewertungskriterium kann dabei die ähnlichste Farbtemperatur herangezogen werden. Werden alle diese Gesichtspunkte berücksichtigt, ermöglicht die LED‐Technik erstmals die Kombination einer energieeffizienten verbesserten Beleuchtung bei gleichzeitig verbessertem Objektschutz. Optimized lighting for the Bode‐Museum in Berlin. The optimization of museum lighting is based on energetic, luminous, colorimetric and conservation aspects, which seems to contradict each other in part. As an example the energy expenditure of the illumination of the “Bode‐Museum” could be reduced by up to 70 % when replacing conventional HGL‐ by LED‐luminaires. In dimmed mode, this value may increase even further due to a more appropriate dimming characteristic of LED. This is accompanied by a reduced damage by UV radiation and short wavelength part of the visible radiation and at the same time without thermal loading of objects by IR radiation. In addition, the combination of different LED in one luminaire creates a variable luminous colour with very good colour rendering properties. The consideration of the conservation requirements is essential when choosing the correct LED‐lighting, for a simple evaluation criterion the correlated colour temperature can be used. If all these aspects are taken into account, the LED technology enables the combination of enhanced energy‐efficient lighting with improved preservation requirements.