The motto of the Solar Decathlon Europe 21/22 was to convert and expand rather than to demolish and reconstruct. Recycling windows, using biodegradable materials for luminaires and connecting light with sensors represented just some innovative examples of the international university-level student competition in Wuppertal, Germany. For the first time, the competition presented an award for sustainable architectural lighting. This was a question of quality as much as quantity, and that applies equally to daylight and artificial light.
Daylight with generous glazing and recycled windows
Windows and their shading systems play a key role in creating a bright, spacious impression and a visual link to the surroundings. This is especially true for the mostly small-format flats found at the Solar Decathlon 21/22. Large insulation thicknesses lead to revealing depths of 20 to 40 cm and reduce the light incidence, especially with small-format windows. The predominantly used triple glazing with its coatings also weakens the light transmission to typical values of around 70 per cent. However, the team from Aachen improves the light incidence through the slanted window reveals on several sides.
The team from Rosenheim not only offers an energy-efficient solution and even light distribution with its window design but also achieves an attractive view for the living area with appropriately proportioned glazing. Vacuum glazing and a Venetian blind are used on the outside. The grating slats for the arcade, set at an angle of 45°, give the project a sophisticated look. This construction optimises the incidence of daylight for the rooms below and provides a view of the sky from there.
A remarkable recycling solution originates from the creative team Karlsruhe. Instead of insisting on identical window sizes and frame colours in the design, the team looked at a building components exchange for the required photometric properties such as size and transmission. During the planning phase, the team searched platforms like eBay as well as professional companies for large-scale reuse of building materials. As a consequence, this approach leads to a bricolage aesthetic shifting away from strict rational facade grids.
An interesting interplay of light and shadow characterises the design by the team from Stuttgart, in which a grid of suspended, rhombus-shaped photovoltaic elements also functions as shading for the access zone. Some teams also experiment with daylight control, either using a vertical tube for an indoor bathroom (Team Valencia) or distributing daylight to different rooms with a fibre optic system (Team Bucharest).
Flexible infrastructure and a shower of light
With electric lighting, the focus is on flexibility and interesting connections with architectural components. The team from Stuttgart presents a conductive tape where the thin zinc conductor strip, glued to the ceiling and wall, allows for lights with different light distributions to be positioned flexibly. Both the lighting control using DALI and the 48 V supply were through the DC strip. For the bathroom, a full-surface illuminated ceiling with an integrated shower outlet was created for a fresh morning shower of light. Residents can switch between three light moods with different colour temperatures to have the appropriate light spectrum for their circadian rhythm in the morning and in the evening. Icons on the wall with integrated wall sensors provide playful interaction.
Adjustable lighting and dark-sky
The idea of flexibility is also evident in the team from Rosenheim’s HDU. With the pendant lights in the kitchen, the light beam width can be conveniently adjusted with one simple turn. As a result, wheelchair users can work at the kitchen counter without any glare. One challenge was the lighting of the buildings at night, with the requirement to comply with the required minimum lighting level in the area of paths and entrances on the one hand, but not to cause any light pollution on the other. Some teams do without any outdoor lighting completely, which saves energy but resulted in penalty points. The team from Rosenheim designed elegantly shielded lighting on the railing for the ramp and step and created a discreet strip light on the façade with very good visual comfort on and around the building. The concept’s downward lighting also avoids light emission into the atmosphere, making it possible to see the stars according to dark-sky lighting principles.
Light characterised by systems thinking
Architectural lighting is not only defined by the key figures on energy efficiency, as life cycle considerations have clearly gained relevance at the Solar Decathlon Europe in Wuppertal. One visible trend was to use biological materials to build decorative light housings as the teams from Karlsruhe and Rosenheim showed. What is more sustainable from a holistic perspective: Biodegradable materials for decorative lights that look fashionable? Flexible rechargeable lights where the batteries entail ecological risks and the materials may not be in proportion to everyday use? Or lights with durable materials that are more expensive to start with but last much longer and can be used with one single lighting busbar system? With this variety of lighting solutions, SDE 21/22 has made an important contribution to taking a more differentiated look at sustainable lighting.
Sustainable Architectural Lighting Special Award
The Deutsche Lichttechnische Gesellschaft e.V. (LiTG) launched the Sustainable Architectural Lighting Award to highlight the importance of lighting in terms of quantity and quality in sustainable buildings. The first, second and third prizes went to the teams from Karlsruhe, Stuttgart and Rosenheim. "The lighting concept implements values of circular economy and combines state-of-the-art LED technology with innovative, user-oriented lighting design." concluded the jury for the winning team Karlsruhe.
Light matters, a column on light and space, is written by Dr Thomas Schielke. Based in Germany, he is fascinated by architectural lighting and works as an editor for the lighting company ERCO. He has published numerous articles and co-authored the books “Light Perspectives” and “SuperLux”. For more information check www.erco.com, www.arclighting.de or follow him @arcspaces.
