Energy and Buildings 154 (2017) 448–464 Contents lists available at ScienceDirect Energy and Buildings journal homepage: www.elsevier.com/locate/enbuild Impact of street canyon typology on building’s peak cooling energy demand: A parametric analysis using orthogonal experiment Kuo-Tsang Huang ∗ , Yi-Jhen Li Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan a r t i c l e i n f o Article history: Received 25 May 2017 Received in revised form 19 August 2017 Accepted 20 August 2017 Available online 25 August 2017 Keywords: ENVI-met EnergyPlus Urban canyon design Tree planting Urban microclimate a b s t r a c t Urban street geometry and ways of street greening affect the microclimate in street canyons, which affects the cooling energy consumption of the surrounding buildings of the streets. This study employs micro- climate simulation software ENVI-met and building energy simulation tool EnergyPlus, takes Taipei’s hot-and-humid climatic region as an example, to explore how street canyon typology and street greening influence the peak cooling electricity consumption of buildings during the hottest weather conditions as a reference for urban planners to achieve the urban form of low energy consumption. The results show that the streets’ height-to-width ratio (H/W) produces the most significant effect on the energy consumption of buildings, followed by street orientation and density of roadside vegetation. The peak cooling energy consumption of buildings of N-S oriented streets consume 16.9% more energy than SW-NE streets, while buildings in street canyons whose H/W = 0.5 consume 37.13% more energy than those in street canyons whose H/W = 2.0. The energy-conserving effects of street greening factors on street cooling and peak elec- tricity consumption are more significant in streets with shallow street canyons than in those with deeper street canyons. It suggests that in the case of shallow street canyons lacking buildings to provide shading, roadside trees are needed to improve the microclimate, to achieve energy conservation for buildings. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Urban areas occupy 2% of the earth’s land surface, and as of 2009, consumes almost 75% of the global energy resources [1]. In Taiwan, nearly 70% of total population is living in urban areas. High urban- ization results in the urban heat island (UHI) phenomenon, which causes urban thermal environment deterioration, higher health risk, and excessive building energy consumption, especially on hot summer days. High densely populated mega-cities, especially those in Asia, exacerbate the problem. Moreover, the daily energy con- sumption of buildings accounts for 40% of the nationwide total energy consumption annually. Taiwan is located in a subtropical climate, and due to its climate, is dominated by cooling, result- ing the energy consumption of air conditioning accounts for 50% of the annual building energy consumption. As air-conditioned build- ings in cities are also affected by the urban microclimate and the UHI effect, the energy consumption of buildings in cities is gener- ally much higher than that of buildings in rural areas. Against such background, the peak summer electricity load in Taiwan records ∗ Corresponding author. E-mail address: huangkt@ntu.edu.tw (K.-T. Huang). a new high each year, which is close to the country’s total power generation capacity, resulting in electricity curtailment crisis. A study of the trends of building energy consumption in Taiwan’s urban and rural areas showed that energy consumption in urban areas is 81% higher than that in rural areas [2]. There are a myriad of factors affecting urban climate. According to past lit- erature, building density [3], street typology and orientation [4–6], greening and planting in street canyons [7,8], and the thermal prop- erties of the pavement materials of the built environment [9] are the factors affecting the thermal environment of street canyons, which further affect the cooling loads of buildings on both sides of the street. The street canyon space formed by urban streets and buildings is influenced by solar radiation, and coupled with long-wave radiation and short-wave reflection from surrounding buildings, the near-surface air temperature and radiation in street canyons are affected and produce microclimates. A recent research on the effects of street canyon design factors conducted in hot-and- humid Guangzhou, China, revealed that the street orientation has the largest contribution on the thermal comfort at pedestrian level [6]. The high-temperature of urban streets would also lower the heat extraction efficiency of air conditioning equipment in build- ings, which worsens the energy consumption of air conditioning systems [10]. Moreover, shaded by street buildings or obstacles (such as roadside trees), the wind velocity in deep street canyons http://dx.doi.org/10.1016/j.enbuild.2017.08.054 0378-7788/© 2017 Elsevier B.V. All rights reserved.