PV and ETFE in NL

John Hill
2. May 2019
Photo: cepezed | Lucas van der Wee
Project: Bus Station Tilburg, 2019
Location: Spoorlaan, Tilburg, Netherlands
Client: City Council Tilburg
Architect: architectenbureau cepezed, Delft 
Structural Engineer: IMd Raadgevende Ingenieurs, Rotterdam
Mechanical & Electrical Engineer: Nelissen Ingenieursbureau b.v., Eindhoven 
Building Physics, Fire Safety and Sustainability: Nelissen Ingenieursbureau b.v., Eindhoven
Landscape Architect/Urban Planner: Atelier Quadrat, Rotterdam
Lighting: Atelier LEK, Rotterdam
General Contractor: BAM Infra bv, Gouda 
Contractor (steel): Buiting Staalbouw, Almelo 
Contractor (installations): Hoppenbouwers Techniek, Udenhout 
ETFE Roof: Buitink - Technology, Duiven 
Photovoltaics: 250 m² of solar panels on the roof; yield = NOM (zero use on the electric bill)
Photographs: cepezed | Lucas van der Wee (all images courtesy of v2com)
The PV panels power, among other things, the lighting integrated into the awning. (Photo: cepezed | Lucas van der Wee)

Bus Station Tilburg sits directly next to the Tilburg Railway Station, designed by Koen van der Gaast (1923-1993) and completed in 1965. Although the train station's roof structure gives Tilburg a recognizable landmark, overall "the station area is inconveniently organized and the atmosphere is rather unpleasant," in the words of cepezed, which has been involved recently with numerous station improvements. In addition to the new bus station, cepezed has worked on the pedestrian areas to improve circulation and access and just started construction on a couple bicycle sheds that will house up to 7,000 bicycles. Their work is turning the station area into a convenient and pleasant environment.

Behind the awning at the west end of the triangle is a small pavilion with, among other things, facilities for bus drivers. (Photo: cepezed | Lucas van der Wee)

The bus station occupies an elongated triangular island among the bus lanes west of the train station. People transferring to and from buses and trains cross at the tip of the triangle, visible in the top photo. Here, the simplicity of the design and the translucency of the awning — the design's most overt qualities — are apparent. The awning, a steel framework covered with ETFE (ethylene tetrafluoroethylene) foil, follows the edges of the island to give waiting riders generous shelter from the rain or sun. Just as the filtered sunlight gives the canopy a soft glow on sunny days, the integral lighting above the ETFE makes the surface glow at night. 

The bus station sits adjacent to the 1965 train station with its dramatic roof designed by Koen van der Gaast. (Photo: cepezed | Lucas van der Wee)

The photovoltaic (PV) array covers 250 square meters (2,700 sf) above the awning. This area is sufficient enough to supply energy for the lighting of the awning, the digital information signs, and the staff canteen and public transport service point in the pavilion at the west end of the triangle. Surrounded by low buildings, the top of the bus station's awning is a logical surface for solar panels; only clouds will keep sunlight from hitting the array during the day.

Planter edges aligned with the columns provide places to sit. (Photo: cepezed | Lucas van der Wee)

What about cleaning and maintenance? According to cepezed, "The ETFE foil of the awning is self-cleaning and hardly needs any maintenance," and the "unornamented design with a minimum of edges and corners reduces the costs for cleaning." Maintenance of the solar panels happens via an access stair in the pavilion and "walkable cable gutter" along the length of the awning. Given that the bus station "is already prepared for the placement of extra electrical equipment that can quickly charge electrical buses," it appears that cepezed thought of everything with their deceptively simple design.

The solar array above the ETFE can be grasped when the sun shines through the awning. (Photo: cepezed | Lucas van der Wee)
Drawing: architectenbureau cepezed
Drawing: architectenbureau cepezed
Drawing: architectenbureau cepezed
Drawing: architectenbureau cepezed
Drawing: architectenbureau cepezed

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