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Mass-Producible Transparent Flexible Passive-Cooling Film
Hua Shao1,2,3, Junru Niu1,2,3, Yiyun Zhang1,2,3
1Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China.
A new transparent flexible film made from poly(methyl methacrylate) and Cs$_{0.33}$WO$_{3}$ nanoparticles offers efficient passive cooling. This low-cost, mass-producible material reduces indoor temperatures by up to 8.4°C, ideal for windows in buildings and vehicles.
Area of Science:
- Materials Science
- Nanotechnology
- Energy Science
Background:
- Passive cooling is crucial for energy-efficient interior temperature regulation.
- Ideal passive-cooling windows require high mid-infrared (MIR) emissivity, low near-infrared (NIR) transmittance, and high visible (VIS) transmittance.
- Current material solutions face manufacturing and cost challenges for mass production.
Purpose of the Study:
- To develop a mass-producible, low-cost, transparent, and flexible passive-cooling film.
- To meet the spectral requirements for effective passive cooling and daylighting.
Main Methods:
- Fabrication of a composite film using poly(methyl methacrylate) (PMMA) and Cs$_{0.33}$WO$_{3}$ nanoparticles.
- Characterization of the film's optical properties, including transmittance and absorptance.
- Evaluation of the film's passive cooling performance under simulated solar intensity.
Main Results:
- The film exhibits high NIR absorptance (80%) and MIR emissivity (93%), with reasonable VIS transmittance (40%).
- A maximum temperature reduction of 8.4°C was achieved for a coated window compared to an uncoated one.
- The film demonstrated significant cooling in both absorbing chamber and car environments.
Conclusions:
- The developed Cs$_{0.33}$WO$_{3}$ nanoparticle-doped PMMA film is a viable, mass-producible solution for passive cooling windows.
- This technology offers a promising approach for energy savings in buildings and vehicles.
- The film effectively balances cooling performance with daylighting requirements.
