The Sky View Factor (SVF) is a key parameter in urban climate modelling, which quantifies the fraction of the visible sky from a given point and allows for the estimation of incident solar radiation, thermal comfort, and urban heat distribution. High resolution in SVF computation is essential for microclimatic studies in the canopy layer, where detailed representations of urban environments are crucial for understanding variations in heat exposure. Traditional SVF calculation methods often rely on sequential processing of shadow projections, however, these methods are computationally intensive and time-consuming, particularly for urban climate analyses at high resolution.

These computational challenges are further magnified when incorporating complex components such as vegetation, where tree crowns exhibit intricate geometries, partial transparency, and permit sky visibility from beneath the canopy. These properties require detailed modeling to account for light penetration and obstruction. This significantly increases the computational cost of Sky View Factor calculations and extends runtime to hours or even days, depending on scale and resolution.

This study introduces a novel GPU-accelerated ray tracing approach for SVF calculation, designed to address the computational limitations of traditional methods for large-scale analyses. By utilizing NVIDIA GPUs and the CUDA programming framework, the method applies parallel computing to perform ray tracing across the full range of azimuth and altitude angles. It estimates SVFs by systematically weighting blocked rays based on their spatial contributions to the hemisphere.

The accuracy of the developed method is validated through two complementary approaches. First, modelled SVF values are compared against theoretical expectations derived from idealized geometric environments. Additionally, a test case on a neighbourhood in Rotterdam is conducted to compare the results of the developed method against those obtained using an established SVF estimation technique using a serial approach. In addition to accuracy, computational efficiency is evaluated by comparing processing times across different study area extents with those of a CPU-based implementation. The proposed GPU workflow achieves a 99% reduction in processing time compared to traditional shadow casting methods performed on a CPU, while maintaining similarly high resolution and accuracy.

Green infrastructure projects, while enhancing environmental quality, often unintentionally exacerbate socioeconomic inequalities through “green gentrification.” This phenomenon leads to rising property values, demographic shifts, and the displacement of vulnerable populations, raising critical concerns about social justice in urban greening. This study systematically reviews the literature to examine how the distribution of and access to green spaces contribute to green gentrification and explores strategies to mitigate its effects. Based on the analysis of peer-reviewed studies in urban planning, green infrastructure, and social dynamics, four key themes emerge: (i) the spatial and health outcomes of greening interventions, (ii) the socioeconomic impacts of green spaces on property values and resident demographics, (iii) the social justice challenges faced by marginalized communities, (iv) the role of urban policies in moderating gentrification. The findings reveal that while urban greening initiatives provide significant environmental and health benefits, these are often inequitably distributed, disproportionately benefiting wealthier populations and displacing vulnerable groups. Studies highlight the importance of integrating affordable housing policies with green infrastructure projects. This approach aims to prevent the displacement of low-income residents while enhancing urban sustainability and inclusivity. Methodologies employed in the reviewed studies—such as spatial analysis, community surveys, and economic assessments—highlight the complex interactions between green infrastructure, housing markets, and social equity. By outlining implications for policy and future research, this study provides a foundation for shaping urban greening strategies that balance environmental goals with social equity, ensuring sustainable and inclusive urban development.

In recent decades, the increasing frequency, intensity, and duration of heatwaves generated by climate change has posed significant challenges to public health, particularly in urban areas. Despite extensive research on the impacts of heatwaves on human health, there is still a need for enhanced understanding of how, and to what extent, the spatial attributes of urban environments exacerbate these effects at the very local scale. This research addresses this gap and emphasises the importance of analysing the relationship among urban form, climate and health through high resolution geo-spatial data. By investigating the spatial correlations between geolocated cardiovascular and respiratory emergency calls, the modelled universal thermal climate index (UTCI) and selected socio-demographic factors during the summer of 2022 in Milan, this study aims to enhance our understanding of the complex interaction among heat, the built environment, and specific health outcomes. The findings identify geographical locations where emergency calls occur more frequently and where health concerns emerge during hot spells. Morphological and socio-demographic factors both play a critical role in determining vulnerability to heat stress. The results provide valuable insights for identifying high-risk areas, where tailored interventions in terms of planning, governance and urban design may be implemented to address heat-resilience and health-equity in cities.

Reducing greenhouse gas emissions while adapting cities to the consequences of climate change is one of the major challenges in the current energy transition towards a nearly carbon-free built environment. A pressing concern regards the rising of global and urban temperatures, which are expected to increase demand for building cooling and hinder the achievement of decarbonisation goals also in continental climate zones. However, available studies and assessment methods still largely overlook the environmental impacts of cooling measures in future climate conditions. This study investigates the efficiency of implementing passive cooling measures (insulation, triple glazing, solar shading, solar reflectivity of façade and natural ventilation) during the renovation of a Swedish multi-family residential building. Novel indicators and an integrated assessment method are developed by combining a climate and energy model with a carbon footprint assessment to evaluate the carbon efficiency of the measures. The results comparison between a baseline case and applied passive measures for Representative Concentration Pathways RCP4.5 and RCP8.5 in 2018, 2030 and 2050 indicates that natural ventilation, triple glazing and solar shading ensure cooling demand reduction between 13% and 56% and have the lowest carbon footprint among the assessed passive strategies. Implementing a combination of all assessed measures has the largest cooling demand reduction potential but poses a trade-off in terms of carbon footprint.

A city is an organism made of social, economic, cultural, and environmental fabrics, the interactions of which determine the form and functioning of city life. Different disciplines are then involved in analyzing the complex processes of the 21st-century city. The aim of this study was to explore the use of an analytical method that can act as a catalyst for the main players involved in the environmental urban morphology (EUM). This multidisciplinary methodology focuses on the study of public space in dense urban fabrics as a key context for understanding a city. Operationally, the work shows the potential of integrating morphological analysis, pedestrian flow analysis, and environmental analysis and applying them in dense and compact urban fabrics. The first of these analyses methods was carried out using urban survey tools and the geographic information system (GIS) in order to detect the physical forms of the city and develop a number of morphological maps. The second, using the global positioning system (GPS) and on-site detectors, maps pedestrian movement within public spaces. The latter mainly focuses on the microclimatic analysis of public spaces and outdoor comfort, carried out using environmental software such as ENVI-met (4.4 version). The ultimate goal of this study was to achieve the definition of a dynamic, multidisciplinary, and multilayer methodology for the analysis of dense urban fabrics which we believe could be very useful for addressing the regenerative processes of the contemporary city.

Urban form plays a critical role when planning city transitions toward decarbonization. However, in urban climate conditions the complex relationship between urban form and cooling demand remains understudied. This thesis develops integrated approaches and knowledge in the transdisciplinary domain of urban morphology, urban climatology and energy-related fields while addressing the question: ‘How does urban form influence building cooling demand in urban microclimate conditions, and how can the magnitude of the relationship be assessed?’.
By answering this main research question, the thesis delivers a threefold contribution. First, it contributes to the conceptualization and understanding of both the intrinsic and the extrinsic role of urban form, by identifying urban form characteristics that directly influence building cooling demand, and indirectly contribute to shaping urban microclimate conditions in buildings’ surroundings. Second, the thesis contributes to increasing the assessment accuracy of urban form-related climate and energy performance. It does so by developing a quantitative morphological method to identify Local Climate Types (LCTs) and by developing a modelling method that enhances the use of microclimate data as boundary conditions for energy demand assessments. Thirdly, for the city of Rotterdam, the testing of these novel methods provides an understanding of how and to what extent the form of buildings and contexts influence building cooling demand.

Venice is known for its history and beauty and its fragility and potential demise. The city is experiencing an increase in yearly average temperatures affecting outdoor - indoor comfort and average energy expenditure. Owing to existing literature demonstrating how local microclimate depends on urban density, shape, and orientation of buildings and materials, the work studies the influence of changing Venice temperatures by targeting such issues, focusing on an urban fabric typical form, known as Campi. Based on IPCC's future weather predictions for 2050 scenario A1B, the work highlights how the urban fabric configuration affects the local microclimate and outdoor conditions to define how buildings will mitigate and adapt to environmental transitions. The method couples microclimate and outdoor comfort users' perception of Physiological Equivalent Temperature (PET), via ENVI-met. Preliminary results show that the compactness of the urban fabric in Venetian Campi significantly reduces outdoor temperatures due to the increased density of shadow areas in the courtyard or in narrow Venice streets. The role of water is also simulated via ENVI-met, as buildings' materials and indoor energy consumption are assumed as invariant to evaluate the historic urban fabric climate resilience. The results constitute a first step towards understanding to what extent a particular urban fabric type is thermally resilient.

Venice is known for its urban heritage fragility. The city is experiencing an increase in yearly average temperatures affecting outdoor–indoor comfort and average energy expenditure. Owing to existing literature demonstrating how local microclimate depends on urban density, form, and materials, this investigation studies the influence of the changing local climate on Venetian vernacular open spaces, known as Campi. Based on the comparison of contemporary weather and the Intergovernmental Panel on Climate Change’s (IPCC) future predictions for the 2050 scenario, this investigation highlights how Campi’s open spaces and the surrounding buildings, canals, and green public areas contribute to building climate resilience. By employing advanced modelling, the study analyses microclimate and outdoor comfort with respect to users’ perception of Physiological Equivalent Temperature (PET). The ENVI-met tool is used to simulate the thermal behaviour of two representative Campi: SS. Giovanni e Paolo and S. Polo. Despite significant temperature growths, Venetian urban fabric characteristics seem to play a crucial role in strengthening the climate resilience of open spaces, thus preserving outdoor comfort quality in a warmer future. The analysis shows how the historical matrix of open spaces and buildings cooperate. Thus, this study offers a contribution to how built heritage should be considered in light of climate change

Morphological characteristics of cities significantly influence urban heat island intensities and thermal responses to heat waves. Form attributes such as density, compactness, and vegetation cover are commonly used to analyse the impact of urban morphology on overheating processes. However, the use of abstract large-scale classifications hinders a full understanding of the thermal trade-off between single buildings and their immediate surrounding microclimate. Without analytical tools able to capture the complexity of cities with a high resolution, the microspatial dimension of urban climate phenomena cannot be properly addressed. Therefore, this study develops a new method for numerical identification of types, based on geometrical characteristics of buildings and climate-related form attributes of their surroundings in a 25m and 50m radius. The method, applied to the city of Rotterdam, combines quantitative descriptors of urban form, mapping GIS procedures, and clustering techniques. The resulting typo-morphological classification is assessed by modelling temperature, wind, and humidity during a hot summer period, in ENVI-met. Significant correlations are found between the morphotypes’ characteristics and local climate phenomena, highlighting the differences in performative potential between the classified urban patterns. The study suggests that the method can be used to provide insight into the systemic relations between buildings, their context, and the risk of overheating in different urban settings. Finally, the study highlights the relevance of advanced mapping and modelling tools to inform spatial planning and mitigation strategies to reduce the risk of urban overheating.

Although the influence of urban form on microclimate and building thermal processes has been acknowledged, few studies have addressed the influence of overheating mechanisms on heterogeneous urban fabrics for existing historical cities. This study investigates the impact of changing urban climate on indoor temperatures by focusing on three Venice morphological patterns. Through microclimate modelling techniques, outdoor and indoor temperatures are simulated in 2020 and 2050 scenarios. Results show that the compactness of the urban fabric contributes to reducing indoor building temperatures. The analysis suggests that the increased density of shadow areas can mitigate the outdoor temperature values and reduce direct radiation on façades. When comparing the two climate scenarios 2020 and 2050, average indoor temperatures increase in the latter. However, the analysis highlights that the absence of insulation and the relatively high thermal mass of typical Venetian envelopes plays a crucial role in the building thermal processes preserving indoor comfort in a warmer climate future.

Rapid urbanization and densification processes are changing microclimatic environments in cities around the world. Even though previous studies have demonstrated the impact of urban microclimate on space cooling and heating demand, modeling tools employed to support the design process largely overlook microclimatic conditions in assessing building energy performance, making use of data from weather stations often located in rural areas. This paper presents a computational approach for the quantitative analysis of building energy demand at the district scale, including interdependent factors such as local air temperature, relative humidity and wind speed, diversity in building geometry and materials. The method, which couples the microclimate model ENVI-met and the district-scale energy simulation tool City Energy Analyst, is applied to a case study in Zurich, Switzerland, in order to analyze the energy performance of the area on a hot summer day. The study contributes to advance a coupling approach between a microclimate simulation and an energy tool at the district scale. The results showed that the coupled assessment approach can deal with complex interactions between geometry, building materials and energy systems. The consideration of local microclimatic conditions led to a 5% increase in the space cooling demand on the selected day, while the simulated peak cooling load for each building was 8% higher on average. The variation in the space cooling demand was found to be mainly due to an increase in latent cooling demand. Moreover, the coupling method allowed a detailed analysis of energy demand variation at the building level showing that, when considering the local climate patterns, the space cooling demand of the individual buildings varied between −5% and +14% on the selected day. The proposed method represents a next step to reflect the mutual interactions between buildings and microclimate in urban districts and aims at supporting decision-making in the design process.

SPACERGY builds upon the need for planning authorities to develop new models to implement energy transition strategies in the urban environment, departing from the exploitation or reciprocity between space and energy systems. Several policies have been made by each EU nation, but effective and practical tools to guide the urban transformations towards a carbon-neutral future present several challenges. The first challenge is to confront long term changes in envisioning how a specific socio-cultural context can respond to the application of solutions for energy efficiency. Secondly, the engagement of communities in bottom-up approaches mainly includes the sphere of urban planning that underestimates the importance of relating spatial transformations with the energy performances generated in the urban environment. The third challenge regards the tools used for the assessment of the energy performance and the necessity of enlarging the scale in which energy demand is analyzed, from the scale of the building to that of the district. In this context, the project explores the role of mobility, spatial morphologies, infrastructural elements and local community participation in regards to the smart use of local resources. The project addresses a knowledge gap in relation to interactions and synergies between spatial programming, energy and mobility systems planning and stakeholder involvement necessary to improve models of development and governance of urban transformations.

Based on detailed spatial morphology and energy use modeling, SPACERGY develops new toolsets and guidelines necessary to advance the implementation of energy-efficient urban districts. New toolsets are tested in three urban areas under development in the cities of Zurich, Almere, and Bergen, acting as living laboratories for real-time research and action in collaboration with local stakeholders. The results of this research project support planners and decision-makers to facilitate the transition of their communities to more efficient, livable and thus prosperous urban environments.

Although the interrelations between urban microclimates and energy demand have been acknowledged, few workflows integrate microclimatic boundary conditions to predict energy demand in parametric morphological studies. This paper helps bridge this gap by introducing a novel workflow which brings together energy and microclimatic modelling for a synergetic assessment at the block scale. The interrelation between form, energy and urban microclimatic conditions is explored here in the climatic context of Tel Aviv by coupling Envimet and EnergyPlus. The potential of this coupling is explored in three different block typologies, each tested for four different density scenarios focusing on the cooling demand on a typical hot day. Results show the substantial increase of as high as 50% in cooling demand when the microclimatic weather data is taken into account and indicate the potential to capitalize on new computational tools which allow to quantify the interrelations between urban form, microclimate and energy performance more accurately.

In the implementation of Energy Transition Strategies within urban (re)development projects, processes of spatial negotiation between functional needs (for buildings and transportation infrastructure) and energy solutions able to meet the energy performative targets have been observed. In a large number of urban transformation cases, spatial planning and design decisions are independent trajectories to which the energy optimization adapts, based on the idea that technological measures for reducing the energy consumption and for clean energy production can be adapted or integrated in a second stage at the building scale. Furthermore, competitive dynamics for the use of space, in particular in interventions of redevelopment within dense urban environments, contribute to exacerbate the conflict between the idea/principles for energy transitions and its spatial configuration.
The paper investigates the practice of energy transition in a Swiss case where the ambitious National Energy Strategies confront these obstacles in managing the implementation phase. The decision makers involved in the project of the Hochschulquartier (HQ), the new University Campus in Zurich, have been interviewed to understand how energy and spatial decision are taken and coordinated at the micro and macro level, and to understand the main constrains. The results show that the practice of spatial-energy integrated decisions needs new forms of coordination, decision structure and procedure, as well as a new role for designers.

District-scale energy demand models are powerful tools to understand complex urban areas, however these models generally use average weather data from rural locations, thus overlooking the effects of the urban context on the local climate. In order to analyze the effects of urban microclimate on space cooling demand, this paper uses microclimate simulation results from ENVI-met as inputs to a district-scale energy demand model, the City Energy Analyst (CEA), to assess the performance of a proposed masterplan for a new residential district in Almere, the Netherlands.

In the design practice simulation methods are already widely used to support the understanding of energy performance and to help designers in reducing energy demand during the design process. However, energy simulation tools are largely limited to the individual building level, and urban microclimate conditions and
variations in local wind, solar radiation, and air temperature patterns in which buildings express their energy performance are largely overlooked. In order to include microclimatic data in the computation of space cooling and heating consumption and enlarge the scale of analysis from single buildings to district scale, a new simulation method has been developed. The proposed coupling procedure links the microclimate software ENVI-met and the City Energy Analyst energy simulation tool and it is employed in the energy assessment of a urban re-development project in the city of Zurich, Switzerland. The results show that, considering microclimatic boundary conditions, the average hourly energy loads vary for daytime and night-time peaks and moreover a variation can be noticed in terms of total space heating and cooling consumption on the hottest and coldest day of a typical year.

Within an energy transition process in the urban environment, a successful implementation of strategies requires the capacity of communities to develop and explore various visions and make decisions within an uncertain and complex context. To achieve a reduction of energy demand and to introduce technologies for production, storage and re-use of energy, different scenario types have been applied in energy and spatial planning in order to explore future pathways supporting and guiding decision makers. These are often used to compare the energy performance of different possible solutions and technological measures, underestimating physical and local spatial components to support integrated design processes, where spatial and energy urban systems can create a synergy for a better performance. This paper describes the elaboration and the application of a transdisciplinary Design Oriented Scenarios (DOS) method for energy transition strategies, which is being developed within the framework of the JPI Urban Europe research project ‘SPACERGY’. The DOS method, employed in the Hochschulquartier in Zurich, Switzerland, combines normative, descriptive and explorative components. It aims to help decision makers in a complex multi-actor process by setting common ‘internal’ transition objectives, sharing and creating a multidisciplinary common ground, and exploring alternative spatial and energy performative visions.