The dynamic thermal conditions profoundly impact on the quality of physical, cultural, and social experiences in courtyard spaces. This research aims to identify the microclimatic dissimilarities between courtyards in terms of tempering seasonal–diurnal thermal extremes and enriching ground-level thermal textures. The methodology included field measurements in summer-2021 and winter-2022 in Cambridge, UK; microclimatic simulations of 107 courtyards in ENVI-met and model validations; and machine learning-driven clustering using Super Organising Maps (SuperSOM). The results indicate that the diurnal thermal range of the spatial-UTCI mean in summer (DTR(M)<24^∘C) is double that in winter (DTR(M)<12^∘C); meanwhile the maximum spatial-UTCI deviation is three times as significant (δ>3^∘Cat 7:00 BST versus δ>1^∘Cat 12:00 GMT). SuperSOM analysis was performed using K-means and hierarchical agglomerative clustering to partition all courtyards into seven subclusters on its graph-lattice structure. Clusters Km_I, Hac_I, and Hac_IV feature a positive synergy between the thermal-tempering and thermal-enriching potentials. In contrast, the other four clusters exhibit conflicting scenarios during the day and night across the two seasons analysed. These data-driven outcomes enabled us to optimise spatial and landscape strategies for designing and retrofitting courtyard microclimates, contributing to the current discussions on climate-responsive and sensation-inclusive design in historical urban contexts.

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The microclimate shaped by urban form is one of the critical determinants for the success of public spaces. To date, hundreds of studies have revealed the potential of mitigating heat and cold stresses by spatial-enclosure strategies to reduce thermal discomfort. However, most of them have placed more emphasis on taming the thermal extremes, rather than on enriching the microclimatic context to benefit the thermal experience. A rich thermal context with varied, mild thermal stress would enhance psychological adaptation, affording flexibility and meeting different thermal preferences of sun, shade, wind and stillness. Therefore, we aim to investigate the morphological effects on these thermal qualities, and to compare not only the cooling performance of geometries but also the microclimatic diversity and hourly fluctuation in thermal stress. More than a hundred fully enclosed courtyards (n=107) were selected across 31 colleges and 10 teaching sites at the University of Cambridge. We have completed 20-hour microclimate simulations at 33 domains with boundary conditions near the summer solstice and the ENVI-met simulation results were fed back into the heatmap through Urbano, Dragonfly and Ladybug plugs-in in Grasshopper. We found much stronger morphological effects on the variations of sun and wind than on air temperature and humidity. The inferential statistical analysis has also shown that the compacity of building shades and the vegetation configurations play crucial roles in taming thermal extremes and enriching the urban thermal contexts at the human scale.@en

This study set out to understand the dynamics of human thermal sensation and perception associated with outdoor thermal variability in urban contexts. Previous studies found that compact urban forms and green features can contribute to urban climate diversity, and conjectured whether the wax and wane of thermal stress can promote thermal satisfaction in outdoor public spaces. Hence, a stop-and-go method has been developed to accurately capture thermal transitions along urban walks and to provide snapshots of the momentary body thermal sensation and subjective thermal perception. The measurement campaigns carried in late summer involved a total of 40 participants walking for 70 min through two waterfront districts in Rome, Italy. Our findings indicate that: (1) the oscillation of air temperature along the dense urban walk is nearly twice as frequent as that along the sparse suburban walk, due to the microclimatic diversity shaped by the compact urban fabrics, pocket parks and tree-lined river banks; (2) the Universal Thermal Climate Index (UTCI) contrast can effectively predict thermal alliesthesia measured by the rate of change of mean skin temperature, (3) subjective perception shows a significant trend but a poorer model fit predicted by UTCI and; (4) two confounders, view and social backgrounds, are proved to affect the regression model between the objective and subjective data. The conclusions emphasise the importance of incorporating spatial and social contexts into the investigation of outdoor thermal comfort via physiological and psychological approaches.@en

Positive Energy Districts (PED) are areas within cities that generate more renewable energy than they consume, contributing to cities’ energy system transformation toward carbon neutrality. Since PED is a novel concept, the implementation is very challenging. Within the European Cooperation in Science and Technology (COST) Action, which offers an open space for collaboration among scientists across Europe (and beyond), this paper asks what the needs for supporting the implementation of PEDs are. To answer this, it draws on Delphi process (expert reviews) as the main method alongside the literature review and also uses surveys as supplementary methods to identify the main challenges for developing PEDs. Initial findings reveal seven interacting topics that later were ranked as highest to the lowest as the following: governance, incentive, social, process, market, technology and context. These are interrelated and interdependent, implying that none can be considered in isolation of the others and cannot be left out in order to ensure the successful development of PEDs. The resources that are needed to address these challenges are a common need for systematic understanding of the processes behind them, as well as cross-disciplinary models and protocols to manage the complexity of developing PEDs. The results can be the basis for devising the conceptual framework on the development of new PED guides and tools.

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Urban microclimatic diversity is of significance to understanding outdoor thermal satisfaction, as it offers a degree of freedom of choice for comfort seeking behaviour, thermal stimulation and potential alliesthesia. The existing assessment of thermal diversity has shown a strong relation to urban 3D geometry. A new workflow is proposed based on previous methods for strengthening the reliability in mapping urban microclimatic diversity. Two new indicators, the gross sun-wind diversity (D%) and the net diversity (d%) have been tested in three urban district models via Envi-MET simulation. The results are segmented by 9 grades of physiological equivalent temperature (PET), showing the value of including the range and variety of thermal sensations in the assessment of urban comfort. The preliminary findings point to a stronger link between microclimatic diversity and thermal neutrality in transitional seasons than in summer or winter.@en