WINPRINT is an initiative aligned with the goals of the European Green Deal, which aims to reduce energy consumption and achieve climate neutrality by 2050. To help meet this challenge, the project is developing smart windows that are manufactured using sustainable printing technologies and have been designed to improve urban sustainability and climate adaptation.

The project is coordinated by Dr Claudio Roscini, from the Nanostructured Functional Materials Group, representing both ICN2 and the spin-off FutureChromes, and also involves researchers from UPC.

Photochromic windows to regulate heat

The project focuses on multifunctional window coatings that can control the amount of sunlight entering a building. This is achieved using photochromic nanomaterials, which change colour or transparency in response to light. In practice, the windows darken when exposed to strong sunlight, helping to improve the indoor climate, reduce heat accumulation and lower the demand for cooling energy, while remains transparent under low sunlight intensity, reducing the need of artificial light. Preliminary simulation studies conducted in collaboration with IREC (through Cupons Green grant, ACCIÓ) have demonstrated that our windows reduce annual energy consumption and CO₂ emissions associated with cooling systems compared with conventional clear glass. The studies were carried on an office-building model across three different Catalonian climates. In these, the energy-saving performance is comparable to commercial window incorporating solar filters, while maintaining superior visual comfort. Unlike conventional clear glass and solar-filter technologies, our photochromic windows provide the highest levels of daytime indoor illuminance within the comfort range.

In WINPRINT, the team aims to scale up this technology by means of digital inkjet printing, a process that can easily be adapted for local industries and applied to glass and other transparent materials. The resulting prototypes could reduce cooling-related energy consumption by between 10% and 30%, thereby lowering domestic energy costs.

In addition to technological development, WINPRINT will include activities and collaborations focused on technology transfer, science communication, and public engagement. These activities help to bring sustainable, low-emission technologies closer to society. The project has already received funding from both the Ajuntament de Barcelona (Barcelona City Council) and Fundació ”la Caixa” via their joint call for funding of scientific research projects.

This initiative is supported by ACCIÓ (www.accio.gencat.cat) and the Barcelona City Council.