Evaluation of the seasonal effect of increasing albedo on urban climate and energy consumption of buildings in Montreal

Touchaei, Ali G.; Akbari, Hashem

doi:10.1016/j.uclim.2015.09.007

Cited by 32 publications

(7 citation statements)

References 39 publications

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“…Furthermore, higher ground albedo leads to a decrease of air temperature, which agrees with previous studies. When the albedo of road increased from 0.2 to 0.45, the daily-averaged urban heat island intensity of the urban area decreased by about 0.1 • C in Montreal [83]. Similarly, in Rome, a higher improvement of urban temperature is noticed during the daytime where temperature is decreased by 4 • C if the albedo of surfaces increases [84].…”

Section: Discussionmentioning

confidence: 94%

Numerical Simulation of Local Climate Zone Cooling Achieved through Modification of Trees, Albedo and Green Roofs—A Case Study of Changsha, China

Chen

Zheng

2020

Sustainability

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By exploring the cooling potential of tree quantity, ground albedo, green roofs and their combinations in local climate zone (LCZ)-4, LCZ-5, and LCZ-6, this study focuses on the optimum cooling level that can be achieved in open residential regions in Changsha. It designs and models 39 scenarios by integrating in situ measurement and ENVI-met numerical simulation and further compares cooling effects of various combinations of the cooling factors. The results show that (1) an increased number of trees and higher albedo are more effective compared to green roofs in reducing summer potential temperatures at street level (2 m high) in three LCZs. Negative correlations are observed in the pedestrian air temperature with trees and ground albedo; (2) the effects of cooling factors vary among different LCZ classes, with the increased 60% more trees leading to lower outdoor temperatures for LCZ-4 (0.28 °C), LCZ-5 (0.39 °C), and LCZ-6 (0.54 °C), while higher albedo of asphalt surface (increased by 0.4) is more effective in LCZ-4 (reaches to 0.68 °C) 14:00, compare to LCZ-5 (0.49 °C) and LCZ-6 (0.38 °C); (3) applying combined cooling methods can provoke air temperature reduction (up to 0.96 °C), especially when higher levels of tree quantities (increased by 60%) are coupled with cool ground materials (albedo increased by 0.4). The results can contribute useful information for improving thermal environment in existing residential regions and future residential planning.

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Section: Discussionmentioning

confidence: 94%

Numerical Simulation of Local Climate Zone Cooling Achieved through Modification of Trees, Albedo and Green Roofs—A Case Study of Changsha, China

Chen

Zheng

2020

Sustainability

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“…The uncontrollable factors, on the other hand, are connected to environment and climate, which consequently lie beyond our control. The warmth produced by anthropogenic sources heats up the urban environment directly, while the solar radiation is partially absorbed by the urban surface and heats up the environment indirectly, over a longer period of time (Touchaei & Akbari, 2015). It is worth to point out here that even though direct solar heating affects urban and rural surface in the same way, it is the indirect solar heating that is one of the biggest causes of UHI and makes the biggest difference.…”

Section: Urban Heat Islandsmentioning

confidence: 94%

“…Temporary effect variables can be cloud cover or wind speed; permanent effect variables are building material, sky view factor or urban green areas system (urban areas contain less vegetation in comparison to rural areas). The cyclic effect variables are solar radiation (which can heat up the environment directlyalbedo or indirectly, by absorbing the heat and emit it slower over time (Touchaei & Akbari, 2015)) and other anthropogenic heat sources (Rizwan et al, 2008). Those are mainly caused by heat released by cars, air conditioning systems or power plants.…”

Section: Urban Heat Islandsmentioning

confidence: 99%

Detection of ventilation corridors using a spatio-temporal approach aided by remote sensing data

Wicht

Wicht²,

Osińska-Skotak

2017

European Journal of Remote Sensing

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The aim of this study is to detect ventilation corridors in three epochs (1992, 2002 and 2011) by mapping rough urban areas. The roughness parameters calculations are based on a 3D building database obtained from satellite imagery (SPOT) for thee epochs and are conducted accordingly to morphometric methods. Several ventilation paths are clearly recognisable for all three decades and based on the proximity analysis and roughness parameters (by calculating roughness length (z 0 ) and zero-plane displacement height (z d )), we established their extent and analysed the structural and developmental changes. We conducted that changes occurred more rapidly in the second periodalmost 90% of the study area was gradually built up, what obstructs the air flow. In addition, winds are blocked in the western part of the citywhere the best wind conditions occur. The results urge to re-evaluate the current shape of ventilation corridors and suggest some new areas that should be included in the air ventilation system to improve citizens' comfort and urban climate. ARTICLE HISTORY

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“…The use of trees (Akbari et al, 2001;Krayenhoff and Voogt, 2007) and greening surfaces (Coccolo et al, 2018) improve the urban comfort and the air quality. Moreover, by increasing the albedo using reflective materials in urban areas, the heat storage and buildings energy consumption can be reduced (Morini et al, 2016;Touchaei and Akbari, 2015). To model these UHI mitigation strategies and to increase the understanding of the phenomenon, different urban climate models have been developed.…”

Section: Introductionmentioning

confidence: 99%

Modeling the effects of future urban planning scenarios on the Urban Heat Island in a complex region

Labedens¹,

Scartezzini²,

Mauree³

2018

Preprint

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Because of the global warming, urban planning strategies must be investigated to reduce the building energy consumption and increase the thermal comfort in cities. In the framework of Energy Strategy 2050 of Switzerland, this research aim to highlight the impact of future climate change on urban planning and proposes strategies to help urban planners and policymakers face this new challenge particularly in a future where heat waves are going to become common at mid-latitudes. However, to do so in the best possible way, the models currently used have to be robust enough in complex regions (with lakes and mountains) to evaluate future planning scenarios. First, this study proposes a methodology to cluster buildings in urban areas and use it in a mesoscale numerical weather prediction system to evaluate the urban heat island and its impact on the energy demand for cooling at the city scale. Second, this research proposes urban planning strategies to reduce building energy consumption due to the urban heat island phenomenon in the city of Lausanne.The model has been validated with six different weather stations. It emphasizes the presence of the urban heat island in the Lemanic region which lead to the increase of air temperatures in Geneva and Lausanne by 2°C during the day and by up 4°C during the night compared to the surrounding areas. The presence of multiple cities around the lake lead to the creation of the urban heat archipelago. We demonstrate with these simulations that the performance of the WRF model is very heterogeneous in this complex setting. In the evaluation of the future urban densification scenario, we noted that there will be an increase in temperature caused by the UHI phenomenon by up 0.6°C. The increase of albedo of roofs and walls and the use of greenings are good mitigation solutions, with a most significant impact for the albedo. In addition to the climatic impact, the model highlights that the densification scenario has a significant impact on the peak cooling demand.

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Evaluation of the seasonal effect of increasing albedo on urban climate and energy consumption of buildings in Montreal

Cited by 32 publications

References 39 publications

Numerical Simulation of Local Climate Zone Cooling Achieved through Modification of Trees, Albedo and Green Roofs—A Case Study of Changsha, China

Numerical Simulation of Local Climate Zone Cooling Achieved through Modification of Trees, Albedo and Green Roofs—A Case Study of Changsha, China

Detection of ventilation corridors using a spatio-temporal approach aided by remote sensing data

Modeling the effects of future urban planning scenarios on the Urban Heat Island in a complex region

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