The current research proposes an integrated computational method to consider the effect of the urban microclimate and the higher urban air temperatures on the assessment of urban building energy demands on an annual basis. A one-way coupling procedure is established to generate datasets on typical weather years that can capture the particularities of the urban microclimate as a function of their morphological and geometrical characteristics, thus providing a global perspective of the annual building energy performance at a reasonable computational cost. The proposed simulation method, here applied for an energy performance analysis of generic, non-insulated building units located in four different urban sites of Thessaloniki, Greece, is based on the three tools: (a) the ENVI-met v.4 microclimate model, (b) the Meteonorm weather generator and (c) the dynamic BEPS tool EnergyPlus. The obtained simulation results indicate a decrease in the annual heating energy needs of the examined building units of 8.2–11.5% when the effect of urban warming was accounted for, along with a rise in the annual cooling energy needs of between 13.4 and 28.2%, depending on the case study area.

This chapter summarizes the basic principles of the Design for Circularity, Design for Adaptability and Design for Disassembly in the design face of building projects. The chapter initially provides a general overview of the circularity principles and the 10R incorporation in the design of circular buildings. At a second step, the basic actions to promote the adaptability and the modularity are presented and discussed.

This chapter examines the primary technical barriers and challenges that impede the transition to a circular economy within the built environment. It highlights the complexities involved in integrating circular practices into the industry which traditionally relies on linear models, government and society. The analysis explores technical barriers at the urban, building and material levels of the built environment through a problem-based approach. Findings highlight a lack of standardized methodologies, inadequate design strategies for reuse and adaptability, insufficient data on material performance, and constraints in current construction practices and regulations. Furthermore, it underscores how technical fragmentation and limited interoperability among systems hinder the advancement of circularity. The chapter also explores the potential benefits of digitalization, design for disassembly, and building information modelling (BIM) as a means to address these challenges. Ultimately, it emphasizes the need for coordinated efforts among stakeholders, supported by robust regulatory frameworks and innovation, to effectively implement circular economy principles in the construction industry.

This study investigates how future climate change will influence urban microclimates in Athens, Greece, focusing on two representative districts classified as Local Climate Zones (LCZ2 and LCZ3). Using the ENVI-met model, microclimate simulations were conducted to assess projected air temperature variations under moderate (Representative Concentration Pathways RCP4.5) and high (RCP8.5) emission scenarios for mid- and late-century conditions. The analysis reveals a consistent warming trend across both districts, with average air temperature increases of approximately 2–3 °C by mid-century and up to 4.5 °C by the end of the century. Morphological characteristics were found to significantly affect thermal behavior: areas with wider street canyons exhibited higher temperatures due to increased solar exposure, whereas shaded inner courtyards remained relatively cooler. The study’s novelty lies in its integration of high-resolution urban microclimate modeling with climate scenario analysis for a Mediterranean metropolis, a combination seldom explored in previous research. The findings underline the importance of incorporating urban morphology into climate adaptation planning, supporting the design of low-carbon and thermally resilient urban forms in densely built environments.

This study presents the preliminary results of the ongoing research project “Re.Nature Cities”, in which the ability of street trees to act as an effective measure against increased urban air temperatures is evaluated via experimental and simulation means. In the existing literature, numerous studies highlight that the addition of street trees inside the canyons of urban areas may result in a significant reduction of the peak ambient summer Tair, having also a prominent effect on outdoor thermal comfort regulation. Yet, street trees also impact urban ventilation as they act as barriers, disturbing the wind flow and affecting buildings’ energy needs and thermal comfort; the positive effect of wind sheltering during the cold winter period, can be thus significantly counterbalanced during the warmer periods of the year. The existing evidence reveals that the green elements’ implementation in the built environment without holistically accounting for all the vegetation-air-buildings interactions, can even exacerbate human discomfort and deteriorate indoor natural ventilation.Based on the above, this study evaluates the mitigation potential of a tree type that is commonly encountered in Greek cities – the citrus- since it has low irrigation needs and high drought tolerance. An integrated experimental campaign, employing wind tunnel measurements, albedo and Leaf Area Index/Leaf Area Density (LAI/LAD) measurements is conducted so as to define of the aerodynamic, thermal and foliage characteristics of real trees. Wind tunnel measurements of total drag are carried out in a wind tunnel section of 3.5m width and 2.5m height, while LAI measurements are conducted using a plant canopy analyzer, with the LAD of each layer (1 m/layer) then calculated from LAI by empirical equations. The obtained values are then used as input parameters in the vegetation model of the ENVI-met microclimate model, which is employed for the evaluation of the thermal environment of typical building blocks in Greece, considering different planting patterns and vegetation coverage scenarios.The experimental database of foliage, thermal and aerodynamic characteristics of common urban tree species, along with the detailed microclimatic simulations of typical urban districts provide a valuable tool for decision-making regarding the optimal vegetation coverage and the planting pattern for urban areas.