Nanostructured photonic materials offer innovative cooling solutions by reflecting solar irradiation and emitting thermal radiation effectively. These materials, like those based on silk fibers and engineered nanophotonic structures, demonstrate exceptional properties for radiative cooling applications. For instance, silk fibers with filamentary air voids can reflect a significant portion of solar radiation and exhibit high thermal emissivity, enabling efficient radiative cooling[1]. Additionally, research at Stanford University has led to the development of nanostructured photonic materials that reflect sunlight while emitting heat into space, achieving passive cooling even during daylight[3]. These materials, made of quartz and silicon carbide, can significantly reduce temperatures and offer a net cooling power exceeding that of standard solar panels[3]. Furthermore, soft, ultrathin photonic materials have been designed to cool wearable electronic devices effectively, enhancing heat dissipation through a combination of radiative and non-radiative cooling mechanisms[5]. These materials, composed of microspheres and nanoparticles, provide a lightweight and flexible solution for thermal management in advanced electronics, demonstrating temperature drops of over 56°C[5]. Overall, nanostructured photonic materials represent a cutting-edge approach to cooling technology, offering efficient and sustainable solutions for various applications.
Harnessing the Cold of Space
Researchers at Stanford University have unveiled a revolutionary cooling structure that operates even under direct sunlight, challenging conventional cooling methods. The team’s novel cooling structures effectively reflect sunlight back into space while dissipating heat. This cutting-edge device, detailed in a paper published in Nano Letters on March 5, marks a significant advancement in the realm of radiative cooling.
The Science Behind the Innovation
Professor Shanhui Fan, the senior author of the study, highlights the dual engineering challenges faced by the team. Firstly, the structure must efficiently reflect sunlight to prevent heat absorption. Secondly, it must emit thermal radiation within a specific wavelength range to escape Earth’s atmosphere effectively.
Nanostructured Photonic Materials: Key to Success
By utilizing nanostructured photonic materials, the researchers achieved a breakthrough in daytime radiative cooling. These engineered materials enable precise control over light reflection and heat emission, paving the way for high-performance and practical applications.
Implications for Sustainable Cooling Solutions
The new cooling structure boasts a remarkable cooling power exceeding 100 watts per square meter, rivaling traditional solar panels in energy generation. This technology holds immense potential for offsetting air conditioning needs in buildings, offering a sustainable and passive alternative to conventional cooling systems.
A Greener Future with Radiative Cooling
Unlike energy-intensive air conditioners, radiative cooling is a passive technology with no moving parts or energy requirements. Its ease of installation and maintenance make it an attractive solution for sustainable cooling needs, heralding a new era of environmentally friendly building design.
Plasmonic Nanostructures
Research has shown that nanostructures, particularly plasmonic nanostructures, offer an excellent platform for merging renewable and sustainable energy sources for cooling applications[2]. These nanostructures have the potential to enhance cooling systems without the need for additional electric power or cooling fluids[3].
Aerogel Materials
Additionally, recent studies have demonstrated the effectiveness of passive cooling systems utilizing aerogel materials, which combine evaporative cooling, radiative cooling, and insulation in one architecture[4]. Despite these advancements, the mass production of certain materials like aerogels remains a challenge due to cost and production requirements[4].
Self-Cooling Paint
One example is a self-cooling paint developed by SRI, which reflects 96% of sunlight and radiates heat in the infrared spectrum, achieving cooling effects up to 10˚F below ambient air temperature and 23˚F below uncoated surfaces[11].
2024 Update
This story first was first written in March of 2013. After 11 years, where are the passively self cooling panels we can buy for buildings?
These innovative cooling solutions have made significant progress. Various advancements have been made in the development of passive cooling technologies, such as self-cooling paint and systems that combine radiative cooling, evaporative cooling, and thermal insulation. These technologies offer efficient and sustainable cooling solutions for buildings, especially in off-grid locations and areas with little or no reliable electric power[7]. The integration of radiative cooling features, evaporative cooling mechanisms, and thermal insulation in these systems has shown promising results in reducing temperatures and providing effective cooling without the need for power or electricity[10]. While specific commercially available passively self-cooling panels for buildings may vary based on manufacturers and regions, the overall progress in passive cooling technology has been substantial over the past decade, offering improved solutions for sustainable and energy-efficient cooling in various applications.
Conclusion
The integration of nanostructured materials and innovative design principles has paved the way for a paradigm shift in cooling technology. Harnessing the cold expanse of outer space for daytime radiative cooling represents a significant step towards sustainable and efficient cooling solutions for a greener future.
In conclusion, while nanostructures for passive cooling represent a promising technology with significant benefits in terms of energy efficiency and sustainability, their widespread adoption is hindered by factors such as cost and production challenges.
[1] https://www.nature.com/articles/s41377-018-0033-x
[2] https://onlinelibrary.wiley.com/doi/full/10.1002/adpr.202000106
[3] https://www.understandingnano.com/nanophotonic-radiative-cooling.html
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10787071/
[5] https://www.sciencedaily.com/releases/2023/06/230629125704.htm
[6] https://www.prnewswire.com/news-releases/new-passive-cooling-for-buildings-discussed-by-idtechex-301406834.html
[7] https://news.mit.edu/2022/passive-cooling-off-grid-0920
[8] https://en.wikipedia.org/wiki/Passive_cooling
[9] https://www.yourhome.gov.au/passive-design/passive-cooling
[10] https://www.parc.com/technologies/self-cooling-paint/
[11] https://www.sri.com/press/story/sris-new-paint-provides-a-sustainable-passive-cooling-solution/
[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10941070/
[13] https://worldwidescience.org/topicpages/h/heat%2Butilization%2Bdevice.html
[14] https://worldwidescience.org/topicpages/t/thermoelectric%2Bpower%2Bsupply.html
[15] https://pubs.acs.org/doi/10.1021/acsmaterialsau.3c00032
