Museum Folkwang, Essen

Case Study Conversion to sustainable LED lighting

Category: Arts & Culture, Specials

LED Lighting in Museums - The Art of Lighting Art

In this re-lighting project, the engineers from KOBER Lichtplaner advised the renowned Museum Folkwang in Essen on the conversion to sustainable LED light ceilings (approx. 1,400 square meters) and LED exhibition spotlights (approx. 250 pieces).

After the inventory analysis, the museum systematically worked out the requirements for the new LED museum lighting:

Light ceiling: visual spatial effect
The homogeneous, even and soft lighting effect of the existing light ceiling with fluorescent tubes should be retained. In addition, however, the new LED light ceilings should provide significantly less insight into the lighting components of the lighting system above the closing gauze, thereby harmonizing the interaction of daylight and artificial light. For this purpose, various positions for the optimal installation location and the direction of emission of the new LED light lines were simulated in terms of design and lighting technology, and different gauze materials were tested as the conclusion of the luminous ceiling for an optimal relationship between low visibility and the required lighting effect.

Light ceiling: light colour
The previous luminous ceiling had a limited adjustment range for the light color of 3,000-4,500 degrees Kelvin. The new LED system should allow for continuous adjustment from 2,700K (very warm light) to 6,500K (cool daylight). This gives the curators the freedom, for example, to present an exhibition in defined daylight regardless of the time of day by programming a daylight control in which the brightness and color temperature are adjusted or by maintaining a constant daylight atmosphere with open ceiling sheds. The LED color temperature can thus be optimally adapted to the art being shown and brightness and light color can be coordinated with each other in terms of perception psychology.

Light ceiling: light quality & conservational UV/IR damage factor
The aim was to achieve very high color rendering across the adjustable color temperature range with the new technology. Based on the CRI-14 colors, photometric measurements were carried out in 500K steps and a CRI of consistently greater than 93 was achieved. At the same time, the UV and IR damage factors could be reduced compared to the previous solution for conservation reasons. In addition to the classic calculation and measurement of the illuminance, the color rendering and the color temperature of the installed system were checked using a spectrometer.

Luminous ceiling: Illuminance
Stepless digital dimming of the luminous ceiling was implemented using DALI with a minimum dimming level of 1%, which means that the lighting levels can be scenographically reduced to 50lx on the floor and 30lx on the walls.

Luminous ceiling: heat generation & energy efficiency
Due to their poor efficiency, analogue light sources account for a not inconsiderable part of the heat input from air-conditioned rooms. As a rule of thumb, you often need a ratio of 1:2 between the connected load of analogue lighting and the energy required for room air conditioning - this means that for every 1 watt of connected load light you save approx. 2 watts of energy for air conditioning. The conversion to modern, efficient LED lighting not only reduces the energy consumption of the lighting itself, but also disproportionately the energy consumption of the cooling due to the lower heat input. The new LED light ceiling achieves a luminous flux yield of approx. 100lm/W on average (very good for a "tunable white" application). Thanks to the targeted and less diffuse emission of the new LED light sources, the number of light sources could be significantly reduced and the available light used more efficiently. In total, this resulted in energy savings of almost 80% plus the savings from less air conditioning.

Exhibition lighting spotlights
In addition to the general lighting provided by the LED light ceiling, the exhibits in the room or on the walls are accentuated by spotlights. These were also converted from analog lights to sustainable LED museum spotlights as part of the re-lighting project. In addition to the general high requirements for the LEDs used, the special requirements for the spotlights were worked out so that a better solution than before could be created in terms of design and lighting technology. Through various samples and comparisons, spotlights were finally specified that use a more efficient and stray light-free projection system using high-performance polymer lenses instead of conventional light control through reflectors. Changeable light distributions, stepless on-board dimming down to 0.1% and extensive accessories were also part of the specification.

Maintenance LED lighting system
Maintenance of lighting systems is not only expensive, but a lamp failure during an illuminated exhibition is a significant quality defect. The LEDs of the luminous ceilings and the exhibition spotlights were technically specified and compared down to the last detail. With an LED specification of L90/B10 after 50,000 hours, the maintenance cycles are massively extended.

Project schedule and range of services
KOBER lighting planners supervised the project for around 12 months. During this period, the following services were provided: inventory of the previous lighting, elaboration of the requirements in workshops, implementation of the requirements in lighting specifications, pre-selection of suitable lighting systems and manufacturers, extensive sampling up to the 1:1 mock-up, elaboration of specifications for special lighting development, commissioning , illumination and light scene definition.

Further Case Studies for LED Conversion in Museums:
Museum Draiflessen Collection
City Museum Münster
LED Museum Workshop

KOBER Lichtplaner
Outdoor photo: Website Museum Fokwang
Spotlights images: ERCO GmbH