An apartment building with visionary energy sources

On Zwirnerstrasse in Leimbach, at the foot of Zurich’s Uetliberg, a flagship project for building-integrated photovoltaics and a new hybrid energy concept has been ongoing since the beginning of 2018. Basler & Hofmann simulated the whole energy system for the multiple dwelling with future-proof energy sources and developed a new solar facade system in collaboration with the building’s architects. The system not only looks attractive, it also performs very well from an economic point of view.


René Schmid Architekten

Innovative facade made from over 1,000 shingles

At first glance, the photovoltaic modules (PV modules) are barely noticeable on the facade of the new multiple dwelling, which contains 11 rental apartments. The matte surface of the modules lends the house a sophisticated appearance. The innovative PV facade system, which was developed by Basler & Hofmann’s PV experts in collaboration with the architects, is centred around a stainless steel hook and bracket. One hook holds four PV shingles together. The new system offers significant cost savings compared to conventional PV facades. On the one hand, the system does away with complex substructures. On the other, over 95 per cent of the facade can be covered with modules of the same size – avoiding additional costs for special designs. Installation is incredibly quick and easy – carpenters can attach the modules by hand. The shingles have a generous tolerance absorbency, so there is no need for time-consuming measuring work.

Electricity from the roof through direct and indirect sunlight

New PV modules were also used for the PV roof system: the new, raised modules absorb sunlight on both their front and rear side. In order to increase the reflectivity of the roof surface and thus the light reaching the back of the modules, the roof was covered in a light marble gravel. Compared to conventional modules, the PV experts expect 5 to 10 per cent more power.

Solar power is transformed into gas

Alongside its innovative photovoltaic solutions, the multiple dwelling on Zwirnerstrasse also serves as a flagship project for a new type of hybrid energy concept – any excess solar power can be converted into methane gas and stored in the power-to-gas plant in Rapperswil. An intelligent hybrid box consisting of a heat pump and a combined heat and power system is installed in the house. This decides whether enough solar power is available for the heat pump to use directly, or whether energy should be obtained from the gas network – a visionary approach to using excess power generated in summer during the winter.

Our services

Simulation of energy flows and operational simulation of the whole energy system. Definition of the storage capacity for the hybrid box. Development of the new facade system together with the architects. Planning the facade and supporting the implementation. Planning the roof system. Quality assurance.

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