ASF – Adaptive Solar Facade
Phase 2
Duration /
2018–2021
A/S Team /
G. Kreuzer Sanchez, B. Svetozarevic, K. Hong, A. Schlueter
Phase 1
Duration /
2014–2018
Funding /
EU Climate KIC
A/S Team /
M. Begle, S. Caranovic, J. Hofer, P. Jayathissa,
G. Lydon, Z. Nagy, D. Rossi, A. Schlueter, B. Svetozarevic
Demonstrators /
NEST Hilo
ASF@HoNR
Selected Publications /
1 / B. Svetozarevic, M. Begle, P. Jayathissa, et al. "Dynamic photovoltaic building envelopes for adaptive energy and comfort management," in: Nature Energy 4 (2019): 671–682. DOI
2 / P. Jayathissa, S. Caranovic, J. Hofer, Z. Nagy, A. Schlueter. "Performative design environment for kinetic photovoltaic architecture," in: Automation in Construction 93 (2018): 339-347. DOI Research Collection
3 / P. Jayathissa, M. Luzzatto, J. Schmidli, J. Hofer, Z. Nagy, A. Schlueter. "Optimising building net energy demand with dynamic BIPV shading," in: Applied Energy 202 (2017): 726-735. DOI Research Collection
The building facade greatly impacts how much heat has to be added or removed in order to retain a comfortable indoor climate. Given that these processes vary throughout the year, the A/S Research Group has developed an adaptive solar facade.
The delicate, movable photovoltaic modules can be mounted onto a lightweight structure on the building envelope and are suited for both restoration and new construction projects. Their reduced weight also allows them to be installed in places not suited for conventional solar systems. The modules are multifunctional: Aside from energy production, they offer shading and daylight control for the interior as well as individual adjustments to the view by the occupant. The facade is also equipped to store energy. Excess energy is transformed into pressurised air, which can be stored and used to adjust the movable modules at a later stage, for example in bad weather when no energy is generated. The facade features a dynamic appearance with modules continuously reacting to their environment.
ASF is not considered as an isolated element, but rather as an integral part of the building system. The efficiency depends on the interplay of the facade with other building technology components such as lighting, heating, and ventilation. Solar radiation, for example, can be used to pre-heat the interior space or the facade can offer partial shading while some modules still allow indirect light to enter the room and be reflected from the ceiling thus reducing the need for artificial lighting.
ASF concept: summer (a), winter (b), in relation to the urban context (c) and module detail (d)
The project combines recent developments in architecture, energy technology and soft robotics. Each module can be individually controlled with the help of SoRo-Track, a soft-material actuator, and an orientation control algorithm developed by the project team. To be able to optimally track the position of the sun, the solar cells are able to point at different angles in all horizontal and vertical axes. The CIGS photovoltaic cells are laminated directly onto 400 x 400 mm aluminium panels.
In order to study the ASF under real-life conditions, a first prototype was installed at the House of Natural Resources (HoNR) in Zurich. A second prototype was developed and realized as part of the HiLo unit at NEST. Both ASF implementations function as living labs for further research.
ASF modules positioned at different angles
Detail view of the pneumatic control module
SoRo-Track: a soft-material actuator made of a two-component silicon rubber. It consists of three cylindrical air chambers arranged symmetrically around the centre and held by discs at the top and bottom. Valves control the air flow: air is pumped in or out causing the actuator to deform, in turn adjusting the orientation of each individual module. The actuator for solar tracking applications has been filed for patent in late 2017.