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Journal of ZheJiang University (Engineering Science)  2020, Vol. 54 Issue (10): 1993-2000    DOI: 10.3785/j.issn.1008-973X.2020.10.017
    
Effect of high-albedo roofs on urban heat island and air-conditioning energy consumption
Jin LIANG1(),Kun LUO1,*(),Qiang WANG1,Xu-chao YANG2,Jian-ren FAN1,Jun-xi ZHANG1
1. State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
2. Ocean College, Zhejiang University, Zhoushan 316000, China
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Abstract  

The city of Hangzhou, where high temperature occurred frequently in summer, was selected as a typical high-temperature period of 22—28 July 2017 in order to analyze the mitigation effects of the high-albedo roofs, the urban cooling technology, on the urban heat island in summer and its impact on the cooling load of air-conditioning. The numerical simulation was performed using the weather research and forecasting model (WRF), coupled with the building energy model based on multi-layer building environment parameterization (BEP+BEM). Results show that the roofs with an albedo of 0.85 can reduce the average daily temperature of the urban area by 0.37 °C, while the urban heat island intensity decreases by 0.21 °C. The urban heat island is alleviated to some extent, and the air-conditioning refrigeration load is reduced by about 5.3%. High-albedo roofs show better cooling and energy-saving effects in buildings-intensive business districts than in low-density residential areas. The roof albedo is negatively correlated with the urban 2 m temperature and air-conditioning energy consumption.



Key wordshigh-albedo roofs      urban heat island      air-conditioning energy consumption      weather research and forecasting model (WRF)      building energy model based on multi-layer building environment parameterization (BEP+BEM)     
Received: 18 September 2019      Published: 28 October 2020
CLC:  P 49  
Corresponding Authors: Kun LUO     E-mail: 21727011@zju.edu.cn;zjulk@zju.edu.cn
Cite this article:

Jin LIANG,Kun LUO,Qiang WANG,Xu-chao YANG,Jian-ren FAN,Jun-xi ZHANG. Effect of high-albedo roofs on urban heat island and air-conditioning energy consumption. Journal of ZheJiang University (Engineering Science), 2020, 54(10): 1993-2000.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2020.10.017     OR     http://www.zjujournals.com/eng/Y2020/V54/I10/1993


高反照率屋顶对城市热岛及空调能耗的影响

为了研究高反照率屋顶这一城市降温技术对夏季城市热岛效应的缓解作用及对空调制冷负荷的影响,以夏季高温频发的杭州市为例,选取2017年7月22日—28日作为典型高温时段,采用中尺度天气预报模式(WRF)耦合考虑建筑物能量交换的多层城市冠层参数化方案(BEP+BEM)进行数值模拟. 结果表明,反照率为0.85的屋顶使城市区域日均降温0.37 °C,城市热岛强度减小0.21 °C,城市热岛效应得到了一定程度的缓解,空调制冷负荷降低约5.3%;建筑物密集的商业区的降温和节能效果均优于低密度居住区;屋顶反照率与城区2 m气温及空调能耗均线性负相关.


关键词: 高反照率屋顶,  城市热岛,  空调能耗,  天气预报模式(WRF),  BEP+BEM方案 
Fig.1 Three layers of nested domains and land use types of d03 domain for WRF model
土地类型 建筑平均高度类型 wb / m ws / m αs,w dp /(人·m–2) Tac/K COP tac / h
注:1)百分数表示各类型建筑所占的比例.
LR 5 m, 15%1);10 m, 70%;
15 m, 15%
13 30 0.2 0.01 298 3.5 24
HR 10 m, 20%;15 m, 60%;
20 m, 20%
17 25 0.2 0.01 298 3.5 24
CM 15 m, 10%;20 m, 25%;
25 m, 40%;30 m, 25%
20 20 0.2 0.02 297 3.5 24
Tab.1 Configurations of simulation cases (CTRL, ALB1, ALB2, ALB3)
Fig.2 Simulated and observed 2 m temperature、relative humidity and 10 m wind speed
Fig.3 Daily change of mean and difference of parameters in CTRL and ALB3 urban areas
Fig.4 Daily change of air-conditioning energy comsuption and sensible heat realsed by air-conditiong in CTRL and ALB3 urban areas
Fig.5 Comparison of air-conditioning energy consumption of CTRL and ALB3
城市区域类型 案例名称 t / °C UHII / °C WS10 /(m·s?1 EAC /(W·m?2
CM CTRL 37.60 2.26 2.43 41.48
CM ALB3 37.10 1.93 2.08 39.88
CM ALB3?CTRL ?0.50 ?0.32 ?0.35 ?1.61
HR CTRL 37.06 1.72 2.85 19.96
HR ALB3 36.52 1.36 2.45 18.57
HR ALB3?CTRL ?0.53 ?0.35 ?0.40 ?1.38
LR CTRL 36.49 1.15 3.03 6.77
LR ALB3 36.07 0.91 2.64 6.14
LR ALB3?CTRL ?0.42 ?0.24 ?0.39 ?0.63
Tab.2 Comparison of simulation results between CTRL (control) and ALB3 (albedo is 0.85) in different urban areas in daytime
Fig.6 Comparison of 2 m temperature in nighttime and daytime in CTRL and ALB3
Fig.7 Linear relationship between different albedo and t, UHII, WS10, EAC in urban areas
[1]   张璐, 杨修群, 汤剑平, 等 夏季长三角城市群热岛效应及其对大气边界层结构影响的数值模拟[J]. 气象科学, 2011, 31 (4): 431- 440
ZHANG Lu, YANG Xiu-qun, TANG Jian-ping, et al Simulation of urban heat island effect and its impact on atmospheric boundary layer structure over Yangtze River Delta region in summer[J]. Journal of the Meteorological Sciences, 2011, 31 (4): 431- 440
[2]   ROSENZWEIG C, SOLECKI W D, PARSHALL L, et al Characterizing the urban heat island in current and future climates in New Jersey[J]. Global Environmental Change Part B: Environmental Hazards, 2005, 6 (1): 51- 62
[3]   SANTAMOURIS M On the energy impact of urban heat island and global warming on buildings[J]. Energy and Buildings, 2014, 82: 100- 113
doi: 10.1016/j.enbuild.2014.07.022
[4]   MACINTYRE H L, HEAVISIDE C Potential benefits of cool roofs in reducing heat-related mortality during heatwaves in a European city[J]. Environment International, 2019, 127: 430- 441
doi: 10.1016/j.envint.2019.02.065
[5]   YANG J, KUMAR D L M, PYRGOU A, et al Green and cool roofs’ urban heat island mitigation potential in tropical climate[J]. Solar Energy, 2018, 173: 597- 609
doi: 10.1016/j.solener.2018.08.006
[6]   郭良辰, 王咏薇, 张艳晴 冷却屋顶对南京夏季高温天气的缓解作用[J]. 科学技术与工程, 2018, 18 (21): 16- 23
GUO Liang-chen, WANG Yong-wei, ZHANG Yan-qing Mitigative effect of cool roof on summer high temperature in Nanjing area[J]. Science Technology and Engineering, 2018, 18 (21): 16- 23
[7]   周晓宇, 王咏薇, 孙绩华, 等 冷却屋顶对北京城市热环境影响的模拟研究[J]. 气象学报, 2019, 77 (1): 129- 141
ZHOU Xiao-yu, WANG Yong-wei, SUN Ji-hua, et al A simulation study on the influence roof on the thermal environment in Beijing[J]. Acta Meteorologica Sinica, 2019, 77 (1): 129- 141
[8]   TOUCHAEI A G, HOSSEINI M, AKBARI H Energy savings potentials of commercial buildings by urban heat island reduction strategies in Montreal (Canada)[J]. Energy and Buildings, 2016, 110: 41- 48
doi: 10.1016/j.enbuild.2015.10.018
[9]   KOLOKOTRONI M, SHITTU E, SANTOS T, et al Cool roofs: high tech low cost solution for energy efficiency and thermal comfort in low rise low income houses in high solar radiation countries[J]. Energy and Buildings, 2018, 176: 58- 70
doi: 10.1016/j.enbuild.2018.07.005
[10]   CHEN F, YANG X, ZHU W WRF simulations of urban heat island under hot-weather synoptic conditions: the case study of Hangzhou City, China[J]. Atmospheric Research, 2014, 138: 364- 377
doi: 10.1016/j.atmosres.2013.12.005
[11]   SALAMANCA F, KRPO A, MARTILLI A, et al A new building energy model coupled with an urban canopy parameterization for urban climate simulations-Part I: formulation, verification and a sensitive analysis of the model[J]. Theor Appl Climat, 2009, 99 (3/4): 331- 344
[12]   申冲, 沈傲, 田艳春, 等 城市形态参数对边界层气象条件影响的模拟[J]. 中国环境科学, 2019, 39 (1): 72- 82
SHEN Chong, SHEN Ao, TIAN Yan-chun, et al Assessment of urban morphological structure parameters effects on meteorological fields in planetary boundary layer[J]. China Environmental Science, 2019, 39 (1): 72- 82
[13]   MARTILLI A, CLAPPIER A, ROTACH M An urban surface exchange parameterization for mesoscale models[J]. Bound Layer Meteor, 2002, 104 (2): 261- 304
doi: 10.1023/A:1016099921195
[14]   KUSAKA H, KONDO H, KIKEGAWAL Y, et al A simple single-layer urban canopy model for atmospheric models: Comparison with multi-layer and slab models[J]. Bound layer Meteor, 2001, 101 (3): 329- 358
doi: 10.1023/A:1019207923078
[15]   CHEN F, DUDHIA J, 2001 Coupling an advanced land surface – hydrology model with the Penn state –NCAR MM5 modeling system. Part I: model implementation and sensitivity[J]. Monthly Weather Review, 2001, 129: 569- 585
doi: 10.1175/1520-0493(2001)129<0569:CAALSH>2.0.CO;2
[16]   LIN Y L, FARLEY R D, ORVILLE H D Bulk parameterization of the snow field in a cloud model[J]. Journal of Climate and Applied Meteorology, 1983, 22: 1065- 1092
doi: 10.1175/1520-0450(1983)022<1065:BPOTSF>2.0.CO;2
[17]   MLAWER E J, TAUBMAN S J, BROWN P D, et al Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave[J]. Journal of Geophysical Research Atmospheres, 1997, 102 (D14): 16663- 16682
doi: 10.1029/97JD00237
[18]   FOUQUART Y, BONNEL B, RAMASWAMY V Intercomparing shortwave radiation codes for climate studies[J]. Journal of Geophysical Research Atmospheres, 1991, 96 (D5): 8955- 8968
doi: 10.1029/90JD00290
[19]   NOH Y, CHEON W G, HONG S Y, et al Improvement of the K-profile model for the planetary boundary layer based on large eddy simulation data[J]. Boundary-Layer Meteorolgy, 2003, 107 (2): 401- 427
doi: 10.1023/A:1022146015946
[20]   SANTAMOURIS M, SYNNEFA A, KARLESSI T Using advanced cool materials in the urban built environment to mitigate heat islands and improve thermal comfort conditions[J]. Solar Energy, 2011, 85 (12): 3085- 3102
doi: 10.1016/j.solener.2010.12.023
[21]   BRETZ S E, AKBARI H Long-term performance of high-albedo roof coatings[J]. Energy and Buildings, 1997, 25 (2): 159- 167
doi: 10.1016/S0378-7788(96)01005-5
[22]   王咏薇, 王恪非, 陈磊, 等 空调系统对城市大气温度影响的模拟研究[J]. 气象学报, 2018, 76 (4): 649- 662
WANG Yong-wei, WANG Ke-fei, CHEN Lei, et al Numerical study of effect of indoor-outdoor heat exchange on urban atmospheric temperature[J]. Acta Meteorologica Sinca, 2018, 76 (4): 649- 662
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