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Self-sustained and Insulated Radiative/Evaporative Cooler for Daytime Subambient Passive Cooling
Li Yu1,2, Yimou Huang1, Yanwei Zhao3
1School of Energy Science and Engineering, Central South University, Changsha 410083, China.
ACS Applied Materials & Interfaces
|January 26, 2024
Summary
This study introduces a novel self-sustained and insulated radiative/evaporative cooler (SIREC). This passive cooling technology offers efficient daytime subambient cooling by combining radiative and evaporative methods for energy conservation.
Area of Science:
- Materials Science
- Thermodynamics
- Sustainable Energy
Background:
- Passive cooling is crucial for energy conservation, but current technologies struggle with consistent daytime subambient temperatures and long-term evaporation.
- Existing radiative coolers face limitations in balancing solar reflectance and thermal emittance, while evaporative coolers require continuous water supply.
Purpose of the Study:
- To develop a self-sustained and insulated radiative/evaporative cooler (SIREC) that overcomes the limitations of existing passive cooling systems.
- To investigate the performance of a novel cooler integrating radiative and evaporative cooling mechanisms for enhanced subambient cooling.
Main Methods:
- Fabrication of a multilayered cooler comprising a porous polyethylene film (P-PE), an air layer, and a poly(vinyl alcohol) hydrogel with lithium bromide (PLH).
- Characterization of P-PE optical properties (solar reflectance, infrared transmittance) and vapor permeability.
- Evaluation of the SIREC's cooling performance through integrated radiative and evaporative heat transfer mechanisms, including atmospheric water harvesting by PLH.
Main Results:
- The P-PE layer demonstrated high solar reflectance (0.91) and long-wave infrared transmittance (0.92), facilitating sky radiative cooling.
- The P-PE exhibited excellent vapor permeability (579 s m⁻¹), enabling efficient evaporative cooling with the PLH.
- The PLH's ability to harvest atmospheric water ensured self-sustained operation for daytime evaporative cooling, enhanced by the insulating air layer.
Conclusions:
- The developed SIREC effectively integrates radiative and evaporative cooling for superior daytime subambient performance.
- The self-sustained nature and efficient heat transfer mechanisms highlight the potential of this passive cooling technology.
- SIREC shows promising prospects for widespread adoption in energy-efficient cooling applications.
Keywords:
atmospheric water harvestingevaporative coolingmidinfrared transparentpassive coolingradiative coolingMore Related Videos
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