Wednesday, 28 February 2024
ICN2 Researchers Reveal an Innovative Method for Energy-Saving Smart Window Development
'Research Features' recently published an article that disseminates one of the latest research results published in the 'Chemical Engineering Journal' focusing on a new smart window concept based on paraffin-polymer composites. This technology was patented in 2022-2023 by some members of the Nanostructured Functional Materials group, led by Daniel Ruiz-Molina with UAB Associate Professor, Jordi Hernando.
Over the past few decades, advancements in smart windows research have taken the technology well beyond the confines of the laboratory. However, there are some challenges such as high development costs and the difficulty of producing high-quality materials, which the co-authors of the study have decided to tackle.
The research, conducted by members of the Nanostructured Functional Materials (Nanosfun) group led by Daniel Ruiz-Molina, in collaboration with Jordi Hernando (UAB Associate Professor), introduces a novel approach for creating thermoresponsive smart windows using polymeric films embedded with nanoparticles made from a low-cost, paraffin-based wax. These materials enable smart glasses to adjust their properties in response to various external triggers like temperature, light, or electric voltages, unlike traditional static windows.
Understanding the wonders of this technology
How did the team manage to create such adjustable materials? They integrated wax-based nanoparticles in a plastic composite. When the wax particles are in the solid state, their refractive index matches the one of the polymers, producing a transparent film. In contrast, when these nanoparticles increase the film’s temperature, it leads to a mismatch in the refractive index between the film polymer and the wax material, as the temperature exceeds the melting point of the wax particles. This results in light scattering, which makes the film opaque and gives it an opaque appearance. Consequently, these materials can alter the transmittance in response to changes in environmental temperature. Additionally, the researchers have included photothermal nanoparticles into their polymeric film, enabling the conversion of light into heat. Finally, the heating can be generated using an electric current by coating these composites with conductive materials.
Overall, these films modulate the solar light transmittance by self-adapting the opacity to the external sunlight intensity and temperature conditions or under the user’s control. According to Roscini, one of the members of the group, the wax-based composition of the film's nanoparticles self-adapts to the sunlight intensity and temperature conditions. This allows users "to control the window's degree of transparency in the same way they would open or close shutters (for antiglare and privacy needs)"
Moreover, this technology not only regulates light transmittance but also presents further advantages. It can be prepared from low-cost materials, exhibits high resistance to light degradation, and offers flexibility, scalability, and precise control over its response to temperature changes. Most importantly, the use of these composites leads to a significant temperature drop inside model houses, with a decrease of up to 6°C. This results in a reduction of solar heat gain by 30-38% under warm (30°C) and high light intensity conditions.
Being aware that buildings contribute to approximately 40% of primary energy consumption, the main purpose of the team was to reduce the energy consumption of heating, ventilation, and air conditioning systems. This targeted lowering user costs and CO2 emissions, despite the above-mentioned challenges. Indeed, the results obtained demonstrate how the suggested technology effectively adjusts to various weather conditions, thereby minimising energy usage levels.
Although previous studies showed that smart windows can reduce up to 10% of energy consumption in buildings, additional research is necessary in real-world settings to provide an actual quantitative idea of the energy-saving effect.
Currently, Nanosfun research group at ICN2, in collaboration with Prof. Jordi Hernando from UAB, is actively engaged in valorization projects aimed at bringing their technology closer to the market. These initiatives, such as Producte and AGAUR, concentrate on improving the technology's humidity, scalability, and readiness for commercialization. The ultimate goal is to license this technology to private entities, facilitating its broader adoption and utilization in various industries.
Reference articles:
Otaegui, Jaume Ramon; Ruiz-Molina, Daniel; Hernando, Jordi & Roscini, Claudio (2023). Multistimuli-responsive smart windows based on paraffin-polymer composites. Chemical Engineering Journal 463, 142390. DOI: 10.1016/j.cej.2023.142390
Research Features (2024, Feb. 26). Smart window design offers a host of energy-saving advantages. Research Features. https://researchfeatures.com/smart-window-design-offers-energy-saving-advantages/