BIPV - Building Integrated Photovoltaic

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District Heating Plant in Laces

BIPV architectural system: 
Opaque façade
Semi-transparent façade
Cold façade
Building use: 
BIPV integration year: 
Between 2005 and 2012
Eurac Research
District heating plant BIPV façade system (Günther Wallnöfer)
Via Nazionale 2a, Laces (BZ), Italy

Public institutions (European, national and regional) played a crucial role in planning and partially financing the works. The mayor Karl Weiss, founder and chairman of EGL company, was strongly committed to the project. From the first stage of the building planning process, the Fleischmann & Jansen engineering firm was involved. It provided the structural design, an energy evaluation through ACCA software and an economic assessment of the PV system. Arch. Werner Pircher dealt with the architectural outline. Solarwatt Srl provided the photovoltaic modules. The PV system installation was commissioned to Wallnöfer Günther & Rudolf Snc and completed in 2009.

Aesthetic integration

The district heating plant is placed below a wooden slope of the Ötztal Alps. The photovoltaic system is integrated on the west- and south-facing facades. It creates a dark envelope, which is aesthetically embedded in the surrounding landscape. The modules comply with the irregular shape of the building. The plan was designed based on the biomass burners (Eng. Klaus Fleischmann) and the fronts follow the sloped roof, where another PV plant is applied.

Energy integration

Together with the roof PV system, the integrated modules are measured to cover the 20–30% of the electricity building demand, mainly required by the burners (Eng. Klaus Fleischmann).

Technology integration

The integrated PV modules Solarwatt (M140-36 GEG LK XL) are standard semi-transparent glazed panels made of 36 monocrystalline cells. On the building’s west façade, they are fixed through aluminium profiles to the opaque concrete surface with a distance of 8 cm. The air gap generates a stack effect that guarantees the modules natural ventilation. On the building’s south façade, the modules are used as an exposure opening for the burner house, creating a warm façade directly exposed to the internal space. Thanks to a 10–20% transparency, they allow a natural illumination inside. The same mounting system is fixed to a wooden structure.

Decision making

The building owner (EGL cooperative energy company of Laces) decided to equip the building with a PV plant to partially cover the electric demand of the biomass burners. This was inspired by the provincial programmes aimed to promote solar energy production (Eng. Klaus Fleischmann). The use of renewable energy, which is locally generated, decreases the costs and the environmental impact of the district heating plant. The initial idea was to build a plant on the roof. Later it was decided to install an additional plant on the façades, using the semi-transparent glass modules (Eng. Klaus Fleischmann).

Lesson learnt

On the south-facing facade, the photovoltaic modules are integrated also replacing transparent glazed surfaces. Other than performing the common functions of building envelope components, they are used as shading devices, guaranteeing the internal visual comfort. The same modules are integrated covering opaque surfaces to give a uniform appearance to the building facades. For the same reason, some fake modules were used (non-rectangular modules) on the top of the West facade, following the sloped roof profile. During the construction works, some panels turned out not to have the correct size and were replaced with other ones. (Eng. Klaus Fleischmann)



Project type: 
New construction
Building function: 
Integration system: 
Opaque cold façade
Semi-transparent cold façade


Module type: 
Standard modules
Solar technology: 
Monocrystalline silicon
System capacity [kWp]: 
System size [m²]: 
Module size [mm]: 
1,600 x 800
South, West
Tilt [°]: 


Total cost [€]: 


Maria Reiche Straße 2A, Dresden, Germany


Via Nazionale 2a, Laces (BZ), Italy

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