Aesthetic Energy: How MorphoColor® Technology Assists Building Integration of Solar Modules

The EU has set a target of achieving 700 GW of installed solar capacity by 2030, which corresponds to a solar panel area of around 3,700 million m² [1]. In order to achieve the EU's goal of climate neutrality by 2050, this capacity must be more than doubled. To maintain public acceptance of the large number of solar panels, solar installations must be designed to be architecturally appealing. Building integrated photovoltaics (BIPV) contributes to this goal, because it specifies the integration of photovoltaic modules into the roof or façade of a building. BIPV technology solutions include coloured PV panels which can mimic the colour of the original building material (think terracotta-tiles or grey-slates) or make the panels an attractive a feature (bright or even white façade panels). That is why innovative PV façades are being demonstrated as part of Green Building Neighbourhoods within the PROBONO project.

Sport Hall at Eppingen, Germany using terraccotta MorphoColor® produced by AGC Interpane und Axsun to blend into the original tiled roof. © Fraunhofer ISE.

MorphoColor® developed at and registered by Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany, is one such technology [2]. Inspired by the same mechanism that creates the colour of the blue Morpho-Butterfly, this technology uses a sputtered thin-film filter in combination with micro-structured substrates [3, 4]. The advantages of MorphoColor® are the high saturated colours (vividly perceived colour), exceedingly high angle-dependence colour stability (the variation in colour hue with the viewed angle of the module) and minimal efficiency-losses (5-10 %) of the solar panel. The technology is currently commercially available from the company Megasol with a fantastically wide colour pallet [5]. Two examples of building integrated PV using the MorphoColor® technology are shown below.

Laboratory at the Fraunhofer Institute for Solar Energy Systems, Freiburg, Germany, incorporating patina green MorphoColor® modules in the façade. © Fraunhofer ISE.

In the scope of the PROBONO project the MorphoColor® technology was further developed by the Fraunhofer ISE so the MorphoColor® is coated on position 1 (the outer facing side of the pane) of the module cover glass as opposed to the commercially available technology which is coated on position 2 (the inner module facing side). This can be advantageous for module production as the coated side of the cover glass is not laminated into the module and thus the lamination process remains identical to a standard module. Optically this yields for more saturated colours although less angle stability. MorphoColor® coated samples have been trialled for over two years in outdoor tests and various laboratory climate chambers. Alternative durable dielectric thin films were investigated to with-stand the more challenging exposure conditions that the coating on position 1 is exposed to.

The installation of a coloured PV façade is planned in PROBONO Dublin Living Lab on the façade of the LexIcon Library in Dun Laoghaire, Dublin.

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References

• [1] https://energy.ec.europa.eu/topics/renewable-energy/solar-energy_en

• [2] Höhn, Oliver; Bläsi, Benedikt; Kroyer, Thomas; Hinsch, Andreas; Kuhn, Tilmann: Glazing unit, process for their preparation and their use. Patent no. DE 10 2017 203 105.

• [3] Bläsi, B.; Kroyer, T.; Höhn, O.; Wiese, M.; Ferrara, C.; Eitner, U.; Kuhn, T. E. (2017): Morpho Butterfly Inspired Coloured BIPV Modules. 5 pages / 33rd European Photovoltaic Solar Energy Conference and Exhibition; 2630-2634. DOI: 10.4229/EUPVSEC20172017-6BV.3.70.

• [4] Blasi, Benedikt; Kroyer, Thomas; Kuhn, Tilmann; Hohn, Oliver (2021): The MorphoColor Concept for Colored Photovoltaic Modules. In IEEE J. Photovoltaics 11 (5), pp. 1305–1311. DOI: 10.1109/JPHOTOV.2021.3090158.

• [5] https://megasol.ch/en/color-intensity-generates-power/