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Development of spectrally self-switchable cover with phase change material for dynamic radiative cooling.
- Source :
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Solar Energy Materials & Solar Cells . Mar2023, Vol. 251, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
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Abstract
- Radiative cooling promises an effective strategy against global warming by sending waste heat to the deep universe in a passive manner. However, the mismatch between cooling supply and demand can significantly compromise the efficacy of spectrally-static radiative cooling devices in cold weather. Therefore, the present work introduced paraffin wax as the phase change material (PCM) to develop a spectrally self-switchable cover (SSC) for flexible radiative cooling. The transmittance of the paraffin wax at different temperatures, thicknesses and phases was characterized. In the UV-VIS-NIR band, the transmittance of the paraffin wax was over 90% in the liquid phase but below 5% in the solid phase. In the "atmospheric window" band, the transmission of the paraffin wax in the liquid phase was also much higher than that in the solid phase with a maximum difference of 41.1%. The optical constants of various paraffin waxes in solid and liquid phases were calculated according to the two-thickness inversion method. The average error of transmittance between the calculated and measured values was only 1.8% and 4% for the 0.19–1.1 μm and 8–13 μm bands, respectively. Moreover, the microstructure analysis of the solid-state paraffin wax revealed that the size of paraffin grains was around 10 μm with interlocking and irregular grain boundaries. The integrated multilayered-like structure resulted in a significant transmittance reduction of the solid-state paraffin wax. In the end, self-switchable PE-PCM-PE (polyethylene-phase change material-polyethylene) covers were prepared and spectrally characterized. The paraffin-based cover provided a new and low-cost candidate solution for achieving dynamic radiative cooling. [Display omitted] • The paraffin transmittance is significantly different between liquid phase and solid phase. • The multilayer-like structure of paraffin crystal grains reduces the transmittance of solid-state paraffin. • The optical constants of paraffin are considerably different in liquid and solid phases by the two-thickness inversion method. • The polyethylene-phase change material -polyethylene shows potential as a spectrally self-switchable cover. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09270248
- Volume :
- 251
- Database :
- Academic Search Index
- Journal :
- Solar Energy Materials & Solar Cells
- Publication Type :
- Academic Journal
- Accession number :
- 161278286
- Full Text :
- https://doi.org/10.1016/j.solmat.2022.112125