The Cold Surface project is researching prefabricated building-envelope systems that incorporate innovative photoluminescent materials to reduce heat build-up in façades and improve the thermal performance of buildings. The initiative is coordinated by URDECON with the participation of AIMPLAS, the Plastics Technology Centre, and the Eduardo Torroja Institute for Construction Science (IETCC-CSIC). It aims to reduce the surface temperature of building envelopes by up to 2 °C and cut the energy demand associated with building cooling by between 5% and 10%. The partners indicate that the approach could also help mitigate the urban heat-island effect, a phenomenon intensified in cities by façades, roofs and pavements that absorb solar radiation and act as heat accumulators during the summer.
Every summer, a large share of solar radiation is absorbed by urban construction surfaces. This raises temperatures in urban environments and increases the need to cool buildings and homes, which in turn increases energy consumption and associated emissions. The Cold Surface project addresses this challenge by developing new construction solutions intended to limit the warming of surfaces exposed to the sun.
Photoluminescent materials for building envelopes
Manuel Asensio, Researcher in Construction and Renewable Energy at AIMPLAS, explains that "the COLD SURFACE project is promoting a new generation of architectural envelopes capable of remaining cooler through the use of advanced photoluminescent materials. These solutions are designed to capture part of the ultraviolet radiation and transform it into visible light, thereby reducing the energy converted into heat and limiting the warming of surfaces exposed to the sun."
Cold Surface is researching photoluminescent materials adapted to the conditions of the construction sector. Unlike solutions based solely on solar reflection, these materials absorb part of the ultraviolet radiation and re-emit it as visible light. According to the project partners, this reduces the energy converted into heat and helps cool the surfaces.
"We are also working to develop luminescent compounds that avoid the use of rare earths, which are considered critical raw materials for Europe, while improving their durability and compatibility with construction materials such as concrete," Asensio adds.
The research also includes new simulation and characterisation methodologies for this type of material. The aim is to generate knowledge that can facilitate future uptake by the building sector.
As Gloria Pérez of the Eduardo Torroja Institute for Construction Science (IETCC-CSIC) notes, "there are currently no widely established methodologies for evaluating this type of material in construction applications. The project will generate new testing and simulation protocols that will help us better understand their potential to reduce building temperatures and combat the urban heat-island effect."
Validation under real construction conditions
Cities concentrate materials that absorb and store large amounts of solar energy, causing urban temperatures to be higher than those of surrounding areas. This urban heat-island effect increases energy consumption, reduces thermal comfort and intensifies the impact of heatwaves on the population.
To transfer the technology from the laboratory to real construction, the project will develop full-scale demonstrators. These will allow the partners to assess the performance of the new envelope systems under real operating conditions and at different times of the year.
"One of COLD SURFACE’s main objectives is to validate this technology in real construction solutions and obtain data that will facilitate its future market uptake. We want to develop building-envelope systems that help reduce building overheating and provide new tools to address the challenges posed by climate change in cities," says Antonio Jesús Martínez, Head of Innovation at URDECON, the company coordinating the project.
In addition to its energy and environmental benefits, the initiative is expected to open new opportunities for developing innovative, high-value construction solutions aimed at the decarbonisation and climate adaptation of urban environments.
Cold Surface is a public-private partnership project funded by the Ministry of Science, Innovation and Universities through the Spanish State Research Agency, and co-funded by the European Union and the European Regional Development Fund (ERDF).
