| 1. |
- Gou, Shaoqing, et al.
(författare)
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Passive design optimization of newly-built residential buildings in Shanghai for improving indoor thermal comfort while reducing building energy demand
- 2018
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 169, s. 484-506
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this paper is to optimize the passive design of newly-built residential buildings in hot summer and cold winter region of China for improving indoor thermal comfort while reducing building energy demand. In this respect, this paper investigates the performance of a representative apartment building in the city of Shanghai and evaluates the optimum solutions by using a developed optimization approach, which includes three major steps of 1) setting the model for multi-objective optimization, 2) sensitivity analysis for reducing the dimension of input variables, and 3) multi-objective optimization by using the Non-dominated Sorting Genetic Algorithm II (NSGA-II) coupled with the Artificial Neural Network (ANN), among which a novel indicator for evaluating the annual indoor thermal comfort of residential buildings of Shanghai named Comfort Time Ratio (CTR) is defined based on the modification of Szokolay's theory in terms of bioclimatic analysis, and the impacts of passive design variables on the indoor thermal comfort and building energy demand in terms of different directions are comprehensively investigated. Results of the multi-objective optimization indicate that the residential buildings of Shanghai have a great potential in comfort-improvement and energy-saving. A series of novel optimal passive design tactics for residential buildings in Shanghai are derived accordingly which could be easily understood and conveniently carried out by the architects in practice.
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| 2. |
- Hosseini, Mohammad, et al.
(författare)
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High-resolution impact assessment of climate change on building energy performance considering extreme weather events and microclimate – Investigating variations in indoor thermal comfort and degree-days
- 2022
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Ingår i: Sustainable Cities and Society. - : Elsevier BV. - 2210-6707. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- Climate change and urbanization are two major challenges when planning for sustainable energy transition in cities. The common approach for energy demand estimation is using only typical meso-scale weather data in building energy models (BEMs), which underestimates the impacts of extreme climate and microclimate variations. To quantify the impacts of such underestimation on assessing the future energy performance of buildings, this study simulates a high spatiotemporal resolution BEM for two representative residential buildings located in a 600 × 600 m2 urban area in Southeast Sweden while accounting for both climate change and microclimate. Future climate data are synthesized using 13 future climate scenarios over 2010-2099, divided into three 30-year periods, and microclimate data are generated considering the urban morphology of the area. It is revealed that microclimate can cause 17% rise in cooling degree-day (CDD) and 7% reduction in heating degree-day (HDD) on average compared to mesoclimate. Considering typical weather conditions, CDD increases by 45% and HDD decreases by 8% from one 30-year period to another. Differences can become much larger during extreme weather conditions. For example, CDD can increase by 500% in an extreme warm July compared to a typical one. Results also indicate that annual cooling demand becomes four and five times bigger than 2010-2039 in 2040-2069 and 2070-2099, respectively. The daily peak cooling load can increase up to 25% in an extreme warm day when accounting for microclimate. In the absence of cooling systems during extreme warm days, the indoor temperature stays above 26°C continuously over a week and reaches above 29.2°C. Moreover, the annual overheating hours can increase up to 140% in the future. These all indicate that not accounting for influencing climate variations can result in maladaptation or insufficient adaptation of urban areas to climate change.
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| 3. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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A multi-objective optimization framework for designing climate-resilient building forms in urban areas
- 2020
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Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:3
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Konferensbidrag (refereegranskat)abstract
- With the increasing global awareness about the impacts of climate change on the built environments, the need for improving the climate resilience of buildings is being more acknowledged. Despite the high number of relevant studies, there is a lack of frameworks to assess the resiliency of buildings and urban areas. This study presents a multi-objective framework to optimize the form of buildings against its energy performance and thermal comfort considering its resiliency to the uncertainties of climate change during three thirty-years periods (2010-2099) of a warm region. Three performance sections related to building's form are identified and categorized for the impact assessment including (1) urban form, (2) orientation, and (3) transparency with ten influencing parameters. The analysis of non-dominated solutions out of the optimization process showed that the annual energy performance (cooling and heating demand) of the urban areas can improve about 34% in both typical and extreme weather conditions whilst maintaining thermal comfort by optimizing the overall form of the buildings with similar built density and heights. Moreover, Buildings with 15 to 30-degree rotations and 33% glazing ratio showed the highest energy performance. Finally, the top 20 resilient building forms with the highest energy performance and climate resiliency were selected out of the database of results to derive design suggestions.
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| 4. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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A novel design-based optimization framework for enhancing the energy efficiency of high-rise office buildings in urban areas
- 2019
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Ingår i: Sustainable Cities and Society. - : Elsevier BV. - 2210-6707. ; 49
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Tidskriftsartikel (refereegranskat)abstract
- Designing high-rise buildings is a complex and challenging task involving several parameters and variables. Recently, there have been major attempts to design the overall form of these buildings based on optimization approaches. This paper introduces a multi-objective optimization framework based on Genetic Algorithm, namely Energy Efficient Form-finder (EEF), consisting four main steps of Form-Generation, Form-Simulation, Form-Optimization and Form-Solutions. The EEF with a comprehensive design-based approach is evaluated through five functions considering objectives of minimizing cooling and heating demand and thermal discomfort time while maintaining operative temperature on the defined thermal comfort zone. This work studies the form combination of five reference buildings based on a new technique called “Building Modular Cell” in five different urban areas, resulting in twenty-five distinct design problems. According to the results, there is a great potential to adopt EEF in newly-built projects with a rectangular layout; while it can reduce the annual energy demand and thermal discomfort time of the optimal form combinations around 34% and 12% respectively. Finally, a series of qualitative and quantitative design-aid recommendations are presented based on 1998 best design solutions, which can be used as form-finding rules of thumb by architects and urban designers at the early design stages.
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| 5. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Combining computational fluid dynamics and neural networks to characterize microclimate extremes: Learning the complex interactions between meso-climate and urban morphology
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 829
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Tidskriftsartikel (refereegranskat)abstract
- The urban form and extreme microclimate events can have an important impact on the energy performance of buildings, urban comfort and human health. State-of-the-art building energy simulations require information on the urban microclimate, but typically rely on ad-hoc numerical simulations, expensive in-situ measurements, or data from nearby weather stations. As such, they do not account for the full range of possible urban microclimate variability and findings cannot be generalized across urban morphologies. To bridge this knowledge gap, this study proposes two data-driven models to downscale climate variables from the meso to the micro scale in arbitrary urban morphologies, with a focus on extreme climate conditions. The models are based on a feedforward and a deep neural network (NN) architecture, and are trained using results from computational fluid dynamics (CFD) simulations of flow over a series of idealized but representative urban environments, spanning a realistic range of urban morphologies. Both models feature a relatively good agreement with corresponding CFD training data, with a coefficient of determination R2 = 0.91 (R2 = 0.89) and R2 = 0.94 (R2 = 0.92) for spatially-distributed wind magnitude and air temperature for the deep NN (feedforward NN). The models generalize well for unseen urban morphologies and mesoscale input data that are within the training bounds in the parameter space, with a R2 = 0.74 (R2 = 0.69) and R2 = 0.81 (R2 = 0.74) for wind magnitude and air temperature for the deep NN (feedforward NN). The accuracy and efficiency of the proposed CFD-NN models makes them well suited for the design of climate-resilient buildings at the early design stage.
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| 6. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Evaluating the impacts of urban form on the microclimate in the dense areas
- 2019
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Ingår i: Building Simulation Conference Proceedings. - : IBPSA. - 2522-2708. - 9781713809418 ; 5, s. 3586-3593
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Konferensbidrag (refereegranskat)abstract
- Urban form is consisting of several complex parameters which can affect urban microclimate in the energy calculations; most importantly the geometry of buildings, streets andcanopies. This study with a novel design-based approach generates 400 urban forms in the context of a dense urban area to evaluate the air flow and consequently the ventilation potential with the aids of CFD simulations in the warm months. Results, indicating the impacts of urban form on microclimate showed that by adopting some design-based suggestions, ventilation potential can be increased up to 17.5% even in severe air pollution conditions.
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| 7. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Impacts of Microclimate Conditions on the Energy Performance of Buildings in Urban Areas
- 2019
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Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- Urbanization trends have changed the morphology of cities in the past decades. Complex urban areas with wide variations in built density, layout typology, and architectural form have resulted in more complicated microclimate conditions. Microclimate conditions affect the energy performance of buildings and bioclimatic design strategies as well as a high number of engineering applications. However, commercial energy simulation engines that utilize widely-available mesoscale weather data tend to underestimate these impacts. These weather files, which represent typical weather conditions at a location, are mostly based on long-term metrological observations and fail to consider extreme conditions in their calculation. This paper aims to evaluate the impacts of hourly microclimate data in typical and extreme climate conditions on the energy performance of an office building in two different urban areas. Results showed that the urban morphology can reduce the wind speed by 27% and amplify air temperature by more than 14%. Using microclimate data, the calculated outside surface temperature, operating temperature and total energy demand of buildings were notably different to those obtained using typical regional climate model (RCM)-climate data or available weather files (Typical Meteorological Year or TMY), i.e., by 61%, 7%, and 21%, respectively. The difference in the hourly peak demand during extreme weather conditions was around 13%. The impact of urban density and the final height of buildings on the results are discussed at the end of the paper.
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| 8. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Impacts of urban morphology on reducing cooling load and increasing ventilation potential in hot-arid climate
- 2018
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 231, s. 714-746
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Tidskriftsartikel (refereegranskat)abstract
- Cooling buildings in urban areas with hot-arid climate put huge loads on the energy system. There is an increasing trend in urban energy studies to recognize the urban design variables and parameters associated with the energy performance of buildings. In this work, a novel approach is introduced to investigate the impacts of urban morphology on cooling load reduction and enhancing ventilation potential by studying a high-rise building (target building), surrounded by different urban configurations, during six warm months of the year in Tehran at four major sections including: (1) generating 1600 urban case studies considering three parameters (Urban Density, Urban Building Form, and Urban Pattern) and modelling the urban morphology of Tehran based on a technique namely “Building Modular Cells”, (2) validation study of CFD simulation of the wind flow around buildings, (3) calculating the average cooling load and wind flow at the rooftop of the target building, and (4) investigating sixteen best urban configurations with the lowest cooling load and highest ventilation potential. Results indicate that urban morphology has a notable impact on the energy consumption of buildings, decreasing cooling load and increasing ventilation potential more than 10% and 15% respectively, compared to the typical cases. This work also proposes design solutions for architects and urban designers, based on Top 100 configurations (out of 1600), for improved energy performance and better ventilation of buildings in urban areas.
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| 9. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Interactions between extreme climate and urban morphology: Investigating the evolution of extreme wind speeds from mesoscale to microscale
- 2020
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Ingår i: Urban Climate. - : Elsevier BV. - 2212-0955. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the interactions between urban morphology indicators and extreme weather variables. In this regard, variations of wind speed and air temperature at the urban microscale are studied for three urban morphologies by means of numerical simulations. Each urban model contains ninety-nine calculation points at different locations and heights to assess the variations during two 24-h cycles of extreme low and high wind speeds by introducing a microscale indicator. According to the results, transforming from mesoscale to microscale can considerably dampen the magnitude of wind speed (up to 66%) and amplify the air temperature (up to 39%). Moreover, the urban morphology parameters (layout geometry, final height and urban density) can change the average magnitude of wind speed (up to 23%) and air temperature (up to 16%) at microscale. For extreme low wind speeds (0.16–1.14 m/s), strong correlations exist between the mesoscale and microscale magnitude of wind speed and air temperature, while there is no significant correlation for extreme high wind speeds (12.2–14 m/s). For extreme low wind speeds, stronger buoyancy effects are observed at the urban canopies. An easy-to-setup approach is proposed to count for microscale conditions during extreme low wind speeds in urban climate studies. © 2019 Elsevier B.V.
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| 10. |
- Javanroodi, Kavan, 1988, et al.
(författare)
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Optimization of building form and its fenestration in response to microclimate conditions of an urban area
- 2020
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 172
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Konferensbidrag (refereegranskat)abstract
- Designing building form in urban areas is a complicated process that demands considering a high number of influencing parameters. On the other hand, there has been an increasing trend to design highly fenestrated building envelopes for office buildings to induce higher levels of natural lighting into the workspace. This paper presents a novel optimization framework to design high-performance building form and fenestration configuration considering the impacts of urban microclimate in typical and extreme weather conditions during a thirty-year period of climate data (2010-2039). In this regard, based on the introduced technique and algorithm, the annual energy demand and thermal comfort of over 8008 eligible form combinations with eight different fenestration configurations and seven different building orientation angels were analysed in a detailed urban area to find optimal design solutions in response to microclimate conditions. Results showed that adopting the framework, annual heating, and cooling demand can be reduced by 21% and 38% while maintaining thermal comfort by taking design-based decisions at the early stages of design.
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