Radiative cooling(RC)shows good potential for building energy saving by throwing waste heat to the cosmos in a passive and sustainable manner.However,most available radiative coolers suffer from low cooling flux.The s...Radiative cooling(RC)shows good potential for building energy saving by throwing waste heat to the cosmos in a passive and sustainable manner.However,most available radiative coolers suffer from low cooling flux.The situation becomes even deteriorated in the daytime when radiative coolers are exposed to direct sunlight.To tackle this challenge,an idea of employing both a spectrally selective cover and a spectrally selective emitter is proposed in this study as an alternative approach.A comparative study is conducted among four RC modules with different spectral characteristics for the demonstration of how the spectral profiles of the cover and the emitter affects the RC performance.The results under given conditions show that the RC module with a spectrally selective cover and a spectrally selective emitter(SC/SE)reaches a net RC power of 62.4 W/m^(2)when the solar radiation is 800 W/m^(2),which is about 1.8 times that of the typical RC module with a spectrally non-selective cover and a spectrally selective emitter(n-SC/SE).When the ambient temperature is 30°C,the SC/SE based RC module realizes a daytime sub-ambient temperature reduction of 20.0°C,standing for a further temperature decrement of 9.2°C compared to the n-SC/SE based RC module.展开更多
基金This study was sponsored by the National Key R and D Program of China(2018YFD0700200)H2020 Marie Skłodowska-Curie Actions-Individual Fellowships(842096)+2 种基金National Natural Science Foundation of China(NSFC 51906241,51761145109 and 51776193)Anhui Provincial Natural Science Foundation(1908085ME138)China Postdoctoral Science Foundation(2019M652209).
文摘Radiative cooling(RC)shows good potential for building energy saving by throwing waste heat to the cosmos in a passive and sustainable manner.However,most available radiative coolers suffer from low cooling flux.The situation becomes even deteriorated in the daytime when radiative coolers are exposed to direct sunlight.To tackle this challenge,an idea of employing both a spectrally selective cover and a spectrally selective emitter is proposed in this study as an alternative approach.A comparative study is conducted among four RC modules with different spectral characteristics for the demonstration of how the spectral profiles of the cover and the emitter affects the RC performance.The results under given conditions show that the RC module with a spectrally selective cover and a spectrally selective emitter(SC/SE)reaches a net RC power of 62.4 W/m^(2)when the solar radiation is 800 W/m^(2),which is about 1.8 times that of the typical RC module with a spectrally non-selective cover and a spectrally selective emitter(n-SC/SE).When the ambient temperature is 30°C,the SC/SE based RC module realizes a daytime sub-ambient temperature reduction of 20.0°C,standing for a further temperature decrement of 9.2°C compared to the n-SC/SE based RC module.
