Conference Agenda

Accurate urban microclimate modeling is crucial for understanding and mitigating the urban heat island effect and its effects in outdoor thermal comfort. This study compares results from two urban microclimate simulation engines tested in the Georgia Institute of Technology campus: the OpenFOAM-based urbanMicroClimateFoam solver and ENVI-met. urbanMicroClimateFoam is a fully coupled solver designed to capture complex interactions within urban environments. The simulations are validated using data from on-site weather stations across the campus. By comparing the performance of urbanMicroClimateFoam and ENVI-met, this research evaluates their accuracy, computational efficiency, model complexity, and simulation time. Results show that urbanMicro-ClimateFoam offers more accurate predictions of outdoor thermal comfort and microclimate patterns for this case study. The study confirms the solver's potential for simulating urban heat islands and informing sustainable urban planning strategies. These findings contribute to optimizing urban climate simulation tools, enhancing decision-making for outdoor thermal comfort, and mitigate the urban heat island effects while promoting more resilient cities.

The impact of external wind environment on the surface deterioration of architectural heritage has often been severely underestimated. On the one hand, wind loads directly apply physical damage to building surfaces, while on the other, the wind environment indirectly affects the deterioration of the buildings by altering the hygrothermal status of the surface layer of building materials, which leads to changes in hygrothermal stress. Although extensive research has been conducted on the application of Computational Fluid Dynamics (CFD) in urban architectural environments, there is limited research on ancient city walls and the wind environment they are exposed to, which are essential for heritage preservation. The Nanjing City Wall, constructed in 1366 and enduring over six centuries, has continually been eroded by the natural environment, particularly by the persistent external wind environment, which has gradually caused significant damage to the materials of the wall's outer surface. This study focuses on the Nanjing City Wall, utilizing CFD simulation to quantitatively evaluate the distribution and cumulative effect of pressure on the wall's surface under the dominate wind direction in Nanjing.

In this study, a full-size three-dimensional model of Nanjing City Wall was constructed to accurately reflect its real geometric shape and structural characteristics. The steady Reynolds-averaged Navier-Stokes (RANS) equations was solved to simulate the wind environment around the Nanjing City Wall, using the Realizable k-ϵ model. The results indicate that the pressure on the entire windward surface is greatest in the middle, gradually decreasing towards the sides. The variation in wind pressure along the height of the windward surface is minimal, with the pressure distribution resembling a rectangular shape. On the leeward surface, there is also suction, with higher values on the sides and lower values in the middle. The average value is approximately 75% of the average wind pressure on the windward surface. The variation in wind pressure along the height of the leeward surface is similarly small, also resembling a rectangular distribution. The study results reveal the cumulative effects and variability of the pressure exerted by the external wind environment on the city wall surface. These findings provide important guidance for the preventive conservation of the city wall, such as planting trees around the city wall with higher wind pressure to alleviate the impact of the wind.

Anthropologic climatic shifts combined with the high levels of urbanization urge the global concerns for climate resilience urban development. In consequence to amplified thermal stress in urban areas, several re-searches under-score the positive effects of VGS addressing human well-beings and highlight potential benefit for ecological maintenance and re-duction of greenhouse gas emission. This study evaluates the impact of green façade courtyard morphologies on thermal comfort in four existing urban frameworks within the Mediterranean climates. The research in-vestigated aiming to achieve optimal comfort levels into open spaces, ensuring adaptation to cli-mate change effects. Adopting a qualitative assessment through simulations, this research utilizes Grasshopper and Ladybug Tools to compare existing urban conditions and refined residential blocks.

Ongoing findings provide guidelines for urban planners focusing on mit-igation strategies of extreme heat aiming to achieve optimal comfort for urban citizens. By evaluating ecological solutions, this research attempts to con-tribute to the increasing demand for climate resilience designs while maintaining sustainability.

Energy is a fundamental service in individuals’ everyday life. Adequate energy services of heating, cooling, and lighting are essential to award a satisfactory standard of living for people and safeguard their health. In Europe, 85% of buildings are old and 64% have poor energy performance, then a strong project of energy efficiency measures should be planned to decarbonize the building stock by 2050. Enhancing the energy performance of buildings reduces energy consumption and greenhouse gas (GHG) emissions, lowers energy costs, mitigates energy poverty and increases energy independence, promoting also the health and well-being of citizens. The revised Energy Performance of Buildings Directive IV (EPBD) enables stronger actions by financing energy efficiency investments in the building sector, addressing specifically energy poverty and the need in supporting vulnerable consumers. In particular, energy efficiency measures should protect also tenants by limiting rent increases. The European Commission established also the EU Energy Poverty Advisory Hub to assist member states in tackling energy poverty. Addressing this issue requires urgent action and well-designed policies, grounded in a thorough assessment of planning and implementing energy poverty mitigation actions in buildings.

In this work, Urban Building Energy Modeling (UBEM) are used to evaluate energy consumption and GHG emissions of the building stock at city scale. Different typologies of UBEMS, using data-driven and process-driven models, are presented highlighting their main characteristics. The UBEMs are also used to identify the most effective energy efficiency solutions considering different energy, economic, environmental, and social indicators and indexes. In fact, it is extremely important to understand the energy, economic and emissions savings together with the energy poverty condition in the societies, if the target is to achieve a “just energy transition”. This analysis is applied to the city of Turin, one of the largest Italian cities, where the energy poverty regards 11% of population, also due to the cold winters and the hot-humid summers. A place-based methodology is applied mainly using open-source databases with the support of Geographic Information System (GIS). It is demonstrated that energy efficiency measures and financial incentives can be implemented to combine the beneficial effects in energy savings, economic convenience, environmental impact and energy poverty mitigation. This GIS-based assessment can be replicable to other cities and communities.

The Urban Heat Island (UHI) effect significantly influences building energy performance and carbon emissions, yet current building energy refurbishment often overlooks urban microclimate complexities. This study aims to evaluate both energy consumption and operational CO2 emissions of a residential building before and after retrofit interventions under different urban characteristics. The research employs a coupling simulation approach integrating urban parameters and building performance analysis. The methodology combines computational fluid dynamics (CFD) using ENVI-met 5.6 for microclimate and urban modelling with building energy simulation (BES) using DesignBuilder for energy and carbon emission analysis. Located in Amman, Jordan, where urbanization and climate change are intensifying UHI effects, a case study target building, a typical two-story residential structure of 450m^2, is analyzed in five strategic locations within an urban neighbourhood, each representing different density patterns and urban configurations. The simulation framework incorporates local construction standards and evaluates retrofit scenarios including envelope improvements, HVAC system upgrades, and passive cooling strategies. The context that affects both baseline performance and retrofit effectiveness is examined in terms of variations in energy consumption patterns and associated carbon emissions across different urban densities. This study contributes to the development of context-sensitive retrofit guidelines by establishing clear relationships between urban morphology, building energy performance, and environmental impact. Initial investigation indicates that the same building's energy consumption changes by 4.76% to 23% across different urban densities, owing mostly to the variations in wind velocity and surface temperatures. The implementation of retrofit strategies shows coordinated effectiveness across all urban contexts, with energy consumption reductions directly related to CO2 emission decreases ranging from 38% to 45% across the different urban densities, highlighting the significant effect of urban morphology on both building energy performance and environmental impact.

Over the last decades, the impact of climate change on the urban climate especially during heat waves has been of increasing interest. We analyze the urban climate using a multiscale approach. First the urban climate is analyzed at city scale using mesoscale meteorological models and then downscaled to local scale using urban microclimate modelling. We focus on the design of mitigation scenarios for urban overheating using vegetation, water spraying and enhanced ventilation for neighborhoods undergoing densification. At the urban neighborhood scale, we are interested in the relationship of buildings and to their immediate outdoor environment, especially trees. Urban climate in residential neighborhoods in conjunction with parks and urban forest is studied, focusing on the impact of cooling effects by vegetation and ventilation.

The different balance of heat and mass exchanges in the built urban environment versus the rural one still needs to be elucidated. Cities absorb more heat and do not cool down sufficiently at night, unlike natural environments. This situation is exacerbated during heat waves. Vegetation, such as street trees, grassy areas and even balcony plants, plays a role in regulating outdoor urban conditions. Advances in elucidating the impact of plants, considering the harnessing rainwater and developing plant-inspired solutions will be presented.