Urban scale rooftop super cool broadband radiative coolers in humid conditions  

作　　者：Rupali Khatun Debashish Das Samiran Khorat Sk Mohammad Aziz Prashant Anand Manju Mohan Ansar Khan Dev Niyogi Mattheos Santamouris 

机构地区：[1]School of Environmental Studies,Jadavpur University,Kolkata,India [2]Department of Architecture,Jadavpur University,Kolkata,India [3]Department of Chemistry,Narajole Raj College,Vidyasagar University,Midnapore,India [4]Department of Architecture and Regional Planning,Indian Institute of Technology,Kharagpur,India [5]Centre for Atmospheric Sciences,Indian Institute of Technology,Delhi,India [6]Department of Geography,Lalbaba College,University of Calcutta,Kolkata,India [7]Department of Earth and Planetary Sciences,Jackson School of Geosciences,University of Texas at Austin,USA [8]Fariborz Maseeh Department of Civil,Architectural,and Environmental Engineering,Cockrell School of Engineering,University of Texas at Austin,USA [9]School of Built Environment,University of New South Wales,Sydney,Australia

出　　处：《Building Simulation》2024年第9期1629-1651,共23页建筑模拟（英文）

基　　金：Dev Niyogi acknowledges the William Stamps Farish Chair through the Jackson School of Geosciences at University of Texas;funding from NOAA NIHHIS NA21OAR4310146,NASA Interdisciplinary Sciences(IDS)Program(NNH19ZDA001N-IDS and 80NSSC20K1268),and DOE Urban Integrated Field Labs(IFL).

摘　　要：The presence of water molecules in the air can impact how super cool broadband radiative coolers behave.Higher humidity in the lower atmosphere traps infrared radiation,reducing heat sent back to outer space.In this study,a mesoscale urban climate model is used to evaluate the newly developed super cool materials with broadband emissivity not selective in atmospheric window as an arsenal for urban heat management of tropical wet and dry cities like Kolkata.The results suggest that the energy balance over urban domain has substantially been altered by the city scale deployment of super cool broadband radiative cooling materials on the building rooftop.Bowen ratio and evaporative fraction values were found decreasing and increasing,respectively with a positive directional polynomial(R2=0.968)relationship,after the implementation of super cool broadband radiative cooling materials and in comparison,to the unmitigated scenario.At high solar hour(14:00 LT),additional thermal variables of urban domain such as 2 m air temperature,surface skin temperature,urban canopy temperature,and roof surface temperature decrease by 2.3℃,5.4℃,0.8℃,and 31.7℃,respectively.Reflective super cool broadband materials achieve sub-ambient temperatures up to 11.7℃during peak hours,reduce surface wind speed by 2.5 m s−1,and lower the planetary boundary layer by 1475 m.The average daytime drop is approximately 7.3℃,and at night,it is close to 2.4℃.Deployment induces a“regional high”over urban areas,disrupting sea breeze onset and lowering the planetary boundary layer.Finally,an optimal cooling performance for super cool broadband radiative coolers can be achieved in lower humidity conditions,as their efficiency decreases with increased humidity.Though needing further investigation,these findings of nano-science-based super cool broadband materials offer valuable insights for policymakers and urban planners addressing thermal management in densely packed tropical urban environments.

关 键 词：tropical urban climate extreme urban heat urban heat mitigation radiative cooler WRF-urban model 

分 类 号：TU984[建筑科学—城市规划与设计]