Tempo-spatial thermal comfort analysis of urban heat island with coupling of CFD and building energy simulation

Aghamolaei, Reihaneh; Fallahpour, Marzieh; Mirzaei, Parham A.

doi:10.1016/j.enbuild.2021.111317

Cited by 44 publications

(18 citation statements)

References 51 publications

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“…9,13,14 CFD provides detailed data in all points and can be used for parametric studies. [15][16][17] The accuracy of the steady-state Reynolds Averaged Navier-Stokes (RANS) has been verified in previous studies. [18][19][20][21] Extensive literature is available on ventilation performance regarding IAQ.…”

Section: Introductionmentioning

confidence: 71%

Investigation of displacement ventilation performance under various room configurations using computational fluid dynamics simulation

Askari

Mahdavinejad

Mojtaba

2022

Building Services Engineering Research and Technology

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The performance of a ventilation system affects air quality, thermal comfort, and energy consumption in indoor environments. To evaluate the performance of displacement ventilation under various room configurations, steady Reynolds Averaged Navier–Stokes (RANS) Computational Fluid Dynamics (CFD) simulations were used. The CFD model was validated using measurements of a full-scale test room. The age of air concept was used to evaluate the ventilation performance regarding indoor air quality. The PD index was used to control the case studies for draft risk. Twelve cases with different configurations were systematically studied and compared with the reference case. The configurations included plan aspect ratio, exhaust opening position, inlet position and geometry, and internal heat gains. The results showed that the overall ventilation performance of a room is less sensitive to room configurations compared with local ventilation performance around the occupants. However, almost in all cases, the occupants were exposed to better-than-average air quality in most cases. The results also indicated that when internal heat gains are small, displacement ventilation should be used with caution. Practical application Any HVAC system design is based on assumptions made for ventilation performance. Comprehensive knowledge of the influential factors is critical for an efficient design. Regarding the architecture and interior design, the architects are also involved in the ventilation systems since they have an axial role in decision making for room configuration, including but not limited to room geometry, the position of inlet and outlet air terminals, and heat/pollutant sources. Consequently, the impact of room configuration on ventilation performance is of practical importance in the architecture, engineering, and construction industry.

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Section: Introductionmentioning

confidence: 71%

Investigation of displacement ventilation performance under various room configurations using computational fluid dynamics simulation

Askari

Mahdavinejad

Mojtaba

2022

Building Services Engineering Research and Technology

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“…Access to daylight within buildings is also a challenge if buildings are tightly packed. Dense urban form can have air quality and urban heat implications relating to urban canyon (street width to building height ratio) as well as air flow within cities (Aghamolaei et al, 2021; Oke, 1981). These other factors also need careful consideration.…”

Section: Discussionmentioning

confidence: 99%

Dark cities or cities of light? – sunlight amenity preservation at whole-city scale using a spatio-temporal decision support approach

White

Langenheim

Yang

2022

Environment and Planning B: Urban Analytics and City Science

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Public open spaces are fundamentally important for the health and well-being of citizens in densely populated cities. If not carefully planned, high-density urban development can overshadow adjacent open spaces, resulting in poor quality, dark and oppressive winter conditions. Current planning control approaches for protecting light amenity in cities are often limited to simple overshadowing impact diagrams (e.g. shadows cast on the equinox at 9 a.m., 12 p.m. and 3 p.m.). In cities transitioning from low to higher density, comprising more complex urban forms and more extreme seasonal light amenity dynamics, these static approaches are insufficient. This paper outlines the development of a spatio-temporal design decision support system for analysing and protecting the light amenity of public open spaces, applied to a capital city in Australia. The system described has two parts: Firstly, to assess the overshadowing of existing public open spaces and identify those in need of protection (Part A), and secondly to generate planning restrictions to protect designated open spaces from future deprivation of light (Part B). For Part A, we use a graphics processing unit accelerated aggregate-shadow (15 minute increments) calculation applied to a detailed city-wide 3D model generated from billions of points of aerial survey (LiDAR) data. For Part B, we use a reversed solar ray casting approach we call the ‘Subtracto-Sun’ which allows a user to specify a time range (e.g. 9 a.m.–4 p.m.) for multiple days of the year and subsequent generation of 3D maximum building height development envelopes. The output of this system was used by the local government to inform a proposed planning policy amendment for the City of Melbourne. The findings illustrate the potential for urban professionals to use the system to rapidly assess shadow impacts for existing and proposed, contextually accurate, large, complex urban environments with high levels of geometric and temporal details. The presented results are significant in that we develop and apply our spatio-temporal decision-support approach to a local government area, successfully informing planning height restriction decisions to protect daylight amenity of public open spaces in need of protection. Our method for setting development height restrictions allows for higher density to be achieved, while not increasing the overshadowing of critical open space infrastructure during designated times.

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“…Detailed analysis is required for this scale in order to evaluate the effects of urban blocks in promoting OTC strategies as the urban heat profile of one neighbourhood cannot be generalized to the whole city. 2,67 In this context, the concept of the Local Climatic Zone (LCZ) is introduced to measure intra-urban microclimatic variations. 68 LCZs are in the range of 100 to 10000 m 2 on horizontal scale and represent homogenous climate regions.…”

Section: Spatial Scalementioning

confidence: 99%

“…32 Geometrical characteristics of street canyons such as aspect ratio (height to width), orientation, and canopies change thermal comfort performance and airflow in the urban areas. 2,12 In open spaces, trees, canopies, and morphological characteristics including spatial proportion and dimensions are among the most impactful design and planning strategies to enhance outdoor thermal comfort. 33 In the neighbourhood and district scale, form layout and built-up density are outlined as the important factors, changing the overall thermal performance.…”

Section: Approachesmentioning

confidence: 99%

“…8,9 Therefore, many studies aim to analyse the OTC performance of urban settings and suggest mitigation strategies against the negative effects of thermal discomfort and heat stress. 2,10 A vast majority of literature appeared over recent years, investigated the impact of urban design scenarios on the microclimate condition of urban spaces in both simulation and field studies. Several review studies reviewed the OTC concept in different climatic and spatial contexts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A comprehensive review of outdoor thermal comfort in urban areas: Effective parameters and approaches

Aghamolaei

Azizi

Aminzadeh

et al. 2022

Energy & Environment

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Increased urban air temperature considerably affects the health, comfort and consequently the quality of life in urban spaces. Urban design and planning studies, therefore, face an increasing challenge as they aim to improve Outdoor Thermal Comfort (OTC) and microclimate conditions of urban environments. Analysing OTC is more challenging when compared to indoor thermal comfort since a wider range of interrelated parameters exists in outdoor environments. Therefore, this research aims to classify urban studies that investigate OTC by conducting a comprehensive review based on key metrics such as approaches taken, methodologies and spatial and temporal scales. By extracting the key findings, this research forms an integrated framework of these metrics that presents a thorough view of the OTC concept in the context of climate-sensitive studies. Furthermore, this research elaborates on the main two groups of parameters affecting OTC including environmental and human-based parameters. Exploring the intricate inter-relationships of these two groups of parameters clarifies their contribution to OTC. Results of this study help architects and urban planners to improve their climate-sensitive strategies and support the decision-making process by providing a comprehensive perspective about different aspects of OTC. Finally, recommendations for future research are outlined.

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Tempo-spatial thermal comfort analysis of urban heat island with coupling of CFD and building energy simulation

Cited by 44 publications

References 51 publications

Investigation of displacement ventilation performance under various room configurations using computational fluid dynamics simulation

Investigation of displacement ventilation performance under various room configurations using computational fluid dynamics simulation

Dark cities or cities of light? – sunlight amenity preservation at whole-city scale using a spatio-temporal decision support approach

A comprehensive review of outdoor thermal comfort in urban areas: Effective parameters and approaches

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