The demand for renewable energy is booming!
The only true technology to achieve the net-zero goal by 2050 is the production of solar power in urban areas. Photovoltaic systems require a lot of space, and that is why we can't rely solely on large-scale ground-mounted installations.
To increase societal acceptance of PV systems, it is essential that they not only generate electricity but also serve multifunctional purposes. As the two images below show, the location of PV systems plays a crucial role. Therefore, integrating photovoltaics into buildings is particularly attractive, as no additional land needs to be developed to contribute to the energy transition.
Particularly, photovoltaic systems on roofs and facades are increasingly coming into focus. Switzerland is at the forefront, vigorously promoting this green revolution to accelerate the energy transition and fully exploit the immense solar potential. While rooftop PV systems continue to hold their top position, facade PV systems are catching up rapidly. In this article, we examine the advantages of PV systems on roofs and facades and introduce our innovative Solskin system.
Advantages of Solar PV on the Roof:
Maximum Sun Exposure: Roofs often provide very good sun exposure, allowing for optimal energy generation.
Space-Saving: Installation occurs on existing roof surfaces, not affecting other uses.
Established Technology: Rooftop PV systems are widely used and proven as a reliable solution.
Advantages of Solar PV on the Facade:
Additional Surfaces: Especially in tall buildings, facades offer much larger additional surfaces for solar energy use compared to roofs.
High Performance in Winter: As the sun is lower in winter, the position of vertical systems is ideal here and can generate more energy than systems on the roof.
Multifunctionality: Besides energy generation, PV facades also contribute to shading and thermal insulation.
Weather Resistance: Snow and rain do not adhere to the facade, thus not affecting its capacity.
Easier Cleaning Process: Vertical systems accumulate less dirt, so cleaning is required much less frequently, sometimes only every few years.
Aesthetic Integration: Facade systems can be ideally integrated into building architecture, leading to appealing designs and melding the modules with the facade.
In less densely populated areas, the roof area of a single-family home is sufficient to ensure the self-sufficiency of a household with electricity, heating, and electromobility. In cities, however, the roof area per inhabitant is smaller and is also used for various installations. Logically, in larger and taller buildings, the facades offer more area than the roof. Therefore, cities can only meet the demand for new infrastructure by using facades for power generation.
Unlike roof systems, snow accumulation does not reduce yield in winter. Thanks to the lower position of the sun in winter, vertical solar facades are particularly efficient in energy gain during the winter months. As shown in the graphic on the left, the yields of facade-integrated photovoltaics—represented by the orange curve—are significantly higher in the winter months from November to March than those of roof systems—represented by the green curve.
A disadvantage of facades is that they produce less energy per square meter compared to roofs. However, PV modules do not always have to be oriented at a 30° angle to the south. As the graphic on the right shows, well-oriented vertical systems can also achieve high yields.
Building-integrated photovoltaics (BIPV) are gaining importance, especially in the field of energy-efficient renovations. Studies show that comprehensive BIPV renovations not only significantly improve the energy efficiency of buildings but also make them "climate-proof." This means buildings consume less energy while simultaneously producing a significant portion of their energy, making them more resilient to climate change impacts. PV integration on old and unattractive facades offers an excellent opportunity to give buildings a modern look.
An outstanding example of facade PV integration is the SUVA office building in Zurich. While PV panels were also installed on the flat roof, the main focus is on the custom-made solar panels integrated into the facade's parapet bands, expected to generate about 160 MWh of solar power annually. The combination of roof and facade PV systems can increase electricity production throughout the year. Facade PV systems provide a valuable contribution in the winter months, when roof system yields decline.
Introducing Solskin: The Future of Dynamic Facade Systems
Solskin is an innovative, dynamic facade system that combines solar power production with smart shading. The movable modules, developed with soft-robotic actuators in collaboration with ETH Zurich, balance the thermal and visual comfort of residents, the building's energy efficiency, and electricity production through artificial intelligence. Solskin offers flexible and aesthetically pleasing designs for new constructions as well as retrofits.
As Alexander Züst, Head of Business, emphasizes: "Solskin functions as a fully integrated part of the building and takes on some functions of the main facade. It provides the same functionality as a rooftop PV system in terms of energy production, with the added advantage of being able to track the sun to achieve the highest possible efficiency from the solar cells used in the system. We essentially use the same solar cell technology, so there is no difference in cell efficiency."
Comparison of Solskin with Conventional PV Systems
Compared to traditional facade PV systems, Solskin offers several advantages:
Design freedom: Solskin allows a high degree of design freedom, as the modules are prefabricated but their size makes them highly customizable to fit perfectly into the building envelope.
Dual functionality: Solskin acts as a solar shading and PV system at the same time, saving up to 80% of air conditioning costs.
Lightweight construction: Solskin is around three times lighter than traditional glass PV façades, which is particularly advantageous for buildings with limited load-bearing capacity.
Intelligent control: With Solskin AI, the system offers intelligent building control that goes beyond pure energy generation and optimizes the overall energy management of the building.
Movable PV modules: Thanks to the movable PV panels, Solskin can optimally capture the sunbeams. This leads to an increase in energy efficiency of 40-60%, depending on the daytime and site conditions.
Dynamic aesthetics: Solskin combines a unique communication of sustainability and innovation with energy efficiency and renewable electricity production.
An Appealing Dynamic Second Building: Combining Communication Capability with Energy Generation and Solar Shading
We should not underestimate the motivational role of PV facades, as they are visually exposed solutions. Unlike roofs, PV facades are visibly exposed and have much more potential when it comes to a motivational role. Generally, systems integrated on the roof generate more energy than systems on the facade, but systems integrated on the facade have a much greater motivational effect, making them superior in urban environments.
Conclusion
Solskin combines the advantages of PV roof and facade systems, offering an intelligent solution with Solskin AI to maximize energy efficiency and comfort. From private to public and commercial designs—Solskin offers dynamically adapted solutions to prepare your building for the future.
Sources:
Bundesamt für Energie (BFE)
ETH Zürich
Swissolar
Energeiaplus
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