Photovoltaics as building skin: has its time come?

Efforts to stealthily integrate solar generation into building facades, using products like solar tiles, solar glass and thin film solar, may be wrong-headed. Architect Peter Kuczia would rather we instead celebrate the much-maligned aesthetic of the photovoltaic panel.

The German designer has coined a new term for the approach – Building Exposed Photovoltaics (BEPV, as opposed to Building Integrated PV) – which he explained during a presentation at the International Advanced Building Skins Conference & Expo, in Bern, Switzerland earlier this month.

‘BEPV aims to intentionally expose, or even accentuate photovoltaic panels, while maintaining the characteristics of integration into the building envelope,’ he told RIBAJ. ‘Even using a standard rectangular format, countless design possibilities are possible on building skins.’

Kuczia’s projects make PV a fundamental aspect of the cladding, expressed in a variety of angles and patterns. A guiding principle is that panels are aesthetically pleasing, preferably frameless, and attached invisibly from behind. ‘Their surface should be uniform, without the characteristic ‘patterns’ of conventional cells,’ he said. 

Facades can transform panels in 2D ‘rotational shifts’, such as on Kuczia’s multi-storey carpark in Düsseldorf, Germany, where modules simultaneously function as parapets while spaces in between ventilate individual floors.

Folding panels in 3D can increase the active surface area and, in the case of a commercial building in Kaufbeiren, create a vertical chimney effect under the panels to improve ventilation of the cells to enhance their cooling. Kuczia’s award-winning bike path canopy Solar Veloroute comprises a recurring 3D grid of solar panels.

The architect has also used BEPV in combination with other facade materials, such as fibre-cement cladding on an affordable house in Poland.

According to Kuczia, greater use of solar panels on facades can exploit morning/evening sun not fully exploited by rooftop panels. While it may raise the hackles of traditional-minded residents and planners, he claims using panels as cladding can also eradicate certain problems associated with BIPV solutions.

‘It is easier to match the module to the building dimensions/grid,’ said Kuczia. ‘With BIPV there is no much margin, you have to know the exact grid of modules at the beginning of the planning process. Being forced to use standard products with limited dimensions and mounting options, increases the challenge for architects and planners because this must be taken into account during the design phase, increasing the project workload and complicating the workflow. BEPV allows more flexibility,’ he concludes.