The anticipated rise in urban environmental thermal load, driven by climate warming and the heat island effect, has intensified heat-related risks for urban buildings, prompting a strong push since the early twenty-first century for green infrastructure solutions. Yet, the spatial limitations of densely built environments have led to the integration of vegetated architectural features, with a notable evolution from horizontal greening to the more recent emphasis on vertical greening strategies. In response to this shift, this paper introduces a thermography-based methodology for inspecting the canopies of vertical installations, enabling sustainable monitoring and maintenance practices. The effectiveness of this approach is demonstrated through a comprehensive analysis and quantification of canopy attributes in a case study featuring an indoor living wall.

The warming climate is expected to increase environmental thermal loading on urban buildings. Green infrastructure enhancements have been widely supported as a means to address the resulting heat-related risks, with the challenge of realising enhancements in densely built cities necessitating the consideration of vegetated architectural features. Early efforts promoted horizontal greening, although in recent years ‘vertical greening’ has gained increased prominence. This paper examines the hypothesis that the wider implementation of the latter typology could serve to enhance urban climate resilience, and does so by applying an analysis pathway including the coupling of a novel one-dimensional vertical greening model (VGM) with an urban climate simulation framework to estimate the microclimate and energy-use implications of neighbourhood-scale vertical greening. The simulation results highlighted immediate thermal relief to canyon pedestrians, as well as net annual space-conditioning energy savings for the canyon buildings. These benefits, however, were modest, with a relatively pronounced influence offered for the urban neighbourhood than suburban, and with the living wall category than green facade application. Although the annual savings present potential for the wider implementation in temperate climates, the influence is insufficient to offer it as an exclusive solution, with any widescale application also requiring assessment against other ecosystem benefits and maintenance costs.

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.

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.

The thermal load on urban buildings is expected to increase owing to the adverse influence of a warming climate. As means to address such heat-related risks, green infrastructure enhancements have been widely supported in recent times, while the challenge of realising enhancements in densely built cities has demanded the consideration of vegetated architectural features. Although early efforts promoted horizontal greening, ‘vertical greening’ has gained increased prominence in recent times. This paper examines the hypothesis that this typology serves to enhance the climate resilience of urban built environments, and does so by presenting an analysis pathway including a novel one-dimensional model (VGM) coupled with the TRNSYS modelling framework to estimate the microclimate and energy use implications of their implementation. The pathway’s application at an indoor atrium study highlighted the installation to contribute to a net annual space-conditioning energy consumption saving when air-conditioning was simulated.

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.

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.

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.

Green infrastructure enhancements are widely supported to address urban heat-related risks. The challenge of implementing enhancements in dense cities has necessitated the development of surface greening, with vertical living walls having gained increased prominence in recent years. This paper considered the performance of such in-situ applications to quantify the extents of their influence on the microclimates of two sheltered urban conditions. The results highlight the potency of hygrothermal modifications to be most apparent within the proximate zone, with other phenomena introducing mixing to disrupt influence distribution. Air movement data at the indoor study also highlights a dominant daytime downward flow that encourages the formation of a microscale centripetal thermal system. This flow lacks potency to cause discomfort, although has capacity to present thermal sensation and diversity to occupants. The findings therefore highlight the necessity for installation designers to take account of proximity influence, and in future designs increase building occupant access to their canopies.

Green infrastructure enhancements are widely advocated to address heat-related risks in cities. The challenge of implementing enhancements in dense cities has necessitated the development of surface greening, with living walls having gained increased prominence in recent years. This paper considered such in-situ applications to quantify the extents of their influence on the microclimates of two sheltered urban conditions. The results highlight the potency of hygrothermal modifications to be most apparent within the immediate zone, while the disparity in influence between the two studies suggest that with increased shelter the hygrothermal influence is likely to be relatively weaker. Surface temperature monitoring results from the Indoor case study presented significant variation. While these were not potent enough to cause radiation asymmetry associated discomfort, thermal sensation and diversity to occupants is probable. These findings therefore highlight the necessity for designers to take account of this proximity influence, and in future designs to increase building occupant access to installations.

A warming climate, increasing frequency and severity of extreme heat events, and the heat island effect are cumulatively expected to exacerbate climate thermal loading on urban buildings. This in turn could lead to increased summertime overheating risk, with any active means for addressing this likely to influence future energy consumption and CO2 emission patterns. This paper examines how the microclimatic loading presented by the heat island (UHI) effect influences summertime adaptive comfort in traditional urban residential buildings. The method for addressing this utilises the novel approach of coupling a computationally efficient urban climate model with an established building energy model to simulate a residential street canyon within the London heat island. Key findings highlighted adaptive capabilities to achieve summertime ‘comfort’ in most rooms without the need for energy intensive mechanical cooling. The alternative of using indiscriminate and widespread mechanical cooling within the canyon length is estimated to result in a 0.4 K increase in nocturnal canyon temperatures, and an additional 4.4% of CO2 released to the climate. In contrast, a targeted approach of cooling rooms where adaptive capacity is insufficient more than halves the canyon CO2 emission estimate; which in turn highlights the necessity for detailed overheating assessments in managing energy use in such traditional residential neighbourhoods within UHIs.

To address the call for developing passive climate resilience strategies, the project examines the influence and effectiveness of utilising vertical greening for reducing space-conditioning loads of urban buildings and surrounding microclimates. By examining this focus, the project aims to improve the design of urban built environments that would in turn lead to health and wellbeing enhancements of their growing populations. The purpose of this paper is to present preliminary findings from a monitoring campaign carried out at an indoor atrium case study in Cambridge, UK. Key parameters monitored included soil, surface, and air temperature; relative humidity; and surface air movement. Results obtained show relatively lower air temperature and higher relative humidity levels proximate to the living wall. Wintertime monitoring has also indicated a surface flow pattern that demonstrates the presence of a modest downdraught effect. Although these modifications are modest in magnitude, they could still offer significant localised thermal comfort benefit to building occupants, as well as potential for contributing to a reduced space-conditioning load.

Environmental thermal loading on urban buildings is expected to increase owing to the combined influence of a warming climate, increasing frequency and severity of extreme heat events, and the urban heat island (UHI) effect. This paper presents how a computationally efficient estimation pathway could be utilised to understand UHI influence on building energy simulations. As an example, this is examined by considering UHI influence on the space-conditioning loads of office buildings within urban and suburban conditions, and how the trend of replacing heavyweight facades with lightweight alternatives could affect their surrounding microclimates, as well as building energy use. The paper addresses this through simulations of street canyons based on the urban Moorgate and suburban Wimbledon areas of London. Results show that with all scenarios including the UHI within a dynamic thermal simulation presents between 2.5 and 9.6% net increase in annual space-conditioning. The study also demonstrates that the trend in urban centres to replace heavyweight facades with lightweight insulated alternatives increases space-conditioning loads, which in turn increases UHI intensity to create a warming feedback loop. The study therefore stresses the significance of including microclimate loading from the UHI in estimating urban and suburban energy use, and the combined simulation approach is presented as a computationally efficient pathway for use by built environment designers.

The warming climate, projected increase in frequency and severity of extreme heat events, and the long-established heat island phenomenon are all expected to exacerbate urban environmental thermal loading. Active means used for addressing such risks are likely to increase energy consumption and emission trends to create a positive feedback loop that could threaten the health and wellbeing of urban citizens. In response, passive approaches such as green infrastructure enhancements are widely advocated, and to meet the challenges of implementing enhancements in dense cities, attention has been directed toward encouraging surface greening. This paper recognises this trend and considers vertical greening as a developing interest with application opportunity in both exterior and interior urban environments. A review of available studies and interviews with experts found most observations available to be derived from exterior applications. Interior applications consequently have yet to be investigated to determine relative value to indoor environments where most of human habitation is typically concentrated. The integration of plant science studies in this regard is highlighted as essential to develop a balanced evidence base for the enthusiasm observed for promoting indoor living wall installations.