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Green roofs are strategies for the ecological intensification of cities and a measure of meeting some of the sustainable development goals (SDGs). They have widely been adopted as an adaptation strategy against an urban heat island (UHI). However, they are conventionally soil-based making it difficult and expensive to adopt as a strategy for greening existing buildings (GEB). This paper, therefore, develops a novel green roof system using climbers for thermal-radiative performance. The paper explores the vitality of climbing species as a nature-based strategy for GEB, and for the ecological improvement of the predominantly used cool roofs in sub-Saharan Africa (SSA).

Simulation for the same building Kejetia Central Market (KCM) Redevelopment; the existing aluminium roof (AL), soil-based extensive green roof (GR1) and the proposed green roof using climbing plants (GR2) were performed using ENVI-met. The AL and GR1 were developed as reference models to evaluate and compare thermal-radiative performance of the conceptual model (GR2). The long wave radiation emission (Q_lw), mean radiant temperature (MRT) and outdoor air temperature (T_a) of all three roofing systems were simulated under clear sky conditions to assess the performance and plant vitality considering water access, leaf temperature (T_f) and latent heat flux (LE₀) of GR1 and GR2.

There was no short wave radiation (Q_sw) absorption at the GR2 substrate since the climbers have no underlying soil mass, recording daily mean average Q_lw emission of 435.17 Wm⁻². The soil of GR1, however, absorbed Q_sw of 390.11 Wm⁻² and a Q_lw emission of 16.20 wm⁻² higher than the GR2. The AL recorded the lowest Q_lw value of 75.43 Wm⁻². Also, the stomatal resistance (r_s) was higher in GR1 while GR2 recorded a higher average mean transpiration flux of 0.03 g/sm³. This indicates a higher chance of survival of the climbers. The T_a of GR2 recording 0.45°C lower than the GR1 could be a good UHI adaptation strategy.

No previous research on climbers for green roof systems was found for comparison, so the KCM project provided a unique confluence of dynamic events including the opportunity for block-scale impact assessment of the proposed GEB strategy. Notwithstanding, the single case study allowed a focussed exploration of the novel theory of redefining green roof systems with climbers. Moreover, the simulation was computationally expensive, and engaging multiple case studies were found to be overly exhaustive to arrive at the same meaningful conclusion. As a novelty, therefore, this research provides an alternative theory to the soil-based green roof phenomenon.

The thermal-radiative performance of green roofs could be improved with the use of climbers. The reduction of the intensity of UHI would lead to improved thermal comfort and building energy savings. Also, very little dependence on the volume of soil would require little structural load consideration thereby leading not only to cheaper green roof construction but their higher demand, adoption and implementation in SSA and other low-income economies of the global south.

The reduction of the consumption of topsoil and water for irrigation could avoid the negative environmental impacts of land degradation and pollution which have a deleterious impact on human health. This fulfils SDG 12 which seeks to ensure responsible consumption of products. This requires the need to advance the research for improvement and training of local built environment practitioners with new skills for installation to ensure social inclusiveness in the combat against the intractable forces of negative climate impacts.

Climbers are mostly known for green walls, but their innovative use for green roof systems has not been attempted and adopted; it could present a cost-effective strategy for the GEB. The proposed green roof system with climbers apart from becoming a successful strategy for UHI adaptation was also able to record an estimated 568% savings on topsoil consumption with an impact on the reduction of pollution from excavation. The research provides an initial insight into design options, potentials and limitations on the use of climbers for green roofs to guide future research and experimental verification.

This paper aims to find ways to optimise the thermal performance of this courtyard design in current urban communities in hot arid regions.

The case study for this research is the Dubai sustainable city residential cluster. After collecting weather data from a site visit, four courtyard configurations were suggested and assessed using ENVI-met simulation analysis software to build a virtual model to represent the base case. This model is used to evaluate the thermal behaviour of outdoor urban spaces. The four courtyard layout scenarios were suggested and tested against the base case model. Scenario one is u-shaped, scenario two is linear, scenario three has central buildings with square courtyards and finally, scenario four has u-shaped buildings with square courtyards.

All the courtyard scenarios achieved an adequate level of user satisfaction, and the wind speed and distribution affected the relative humidity of the outdoor areas. The main findings indicate that courtyard scenario four provided the best microclimatic behaviour within the urban community, as the relative humidity dropped from 56.27% to 48% and the temperature was reduced from 43.03 °C to 41.03 °C.

The study was focused on Dubai and on urban levels, but the findings can be generalized to cover most of courtiers that have similar climatic and environmental contexts.

Architects and urban planners will recognize the potential to reduce energy due to natural ventilation and lower solar radiation.

If the findings be applied, this will lead to energy reduction as well as building foot print reduction.

This paper contributes to the existing literature by comprehensively reviewing the concept of courtyards in hot climate and in a region of shortage of studies conducted. It will draw future recommendations of how and where to design courtyards within urban communities.

Traditional central courtyards have been advocated for being thermally efficient for hot-climate regions. However, exploring previous literature shows that it is not clear to what extent courtyards are truly thermally comfortable. This study determines the level of thermal comfort in residential courtyards in hot-climate regions, taking Baghdad as a case study.

This study develops a novel Courtyard Thermal Usability Index (CTUI) to quantify the ability of courtyards to provide thermal comfort to occupants. CTUI is the fraction of useable thermally comfortable hours in courtyards of the total occupation hours during a specific period. To operationalise CTUI, the research employs the Envi-met 4.2 simulation tool to determine the annual thermal conditions of 360 courtyards. An adaptive thermal comfort model developed by Al-Hafith in 2020 for Iraq is used to judge simulated thermal conditions and determine CTUI.

CTUI enables determining the level of thermal comfort courtyards offer to occupants by showing the ratio of the thermally comfortable period versus the occupation period. Results show that, in Iraq, annually, courtyards offer up to 38% comfortable hours out of the total potential occupation hours. The rest of the time the courtyard will not be comfortable, mostly due to overheating. When designing courtyards, the most effective geometric property impacting courtyards' thermal conditions is width/height. The most important microclimatic factor impacting occupants' thermal sensation is mean radiant temperature (MRT). This study can be used to inform designing thermally efficient courtyards for hot-climate regions.

This study presents the first assessment of the thermal efficiency of courtyards in hot-climate regions depending on an assessment of their ability to provide thermal comfort to occupants. The study presents a novel index that can be used to quantify the ability of courtyards to provide a thermally comfortable environment to occupants.

The preservation of historic urban centres prevents anarchic development of the city and ensures a harmonious evolution of the urban form. It also improves the quality of life in the context of climate and environmental change. Morphological and geometric indicators of the urban fabric are key parameters in the formation of external microclimates. They provide a positive effect on the thermal comfort of pedestrians. The objective of this work is to study the impact of the site morphology on the external microclimate and to understand the relationship between the subjective perception and the objective quantification of the thermal environment. The result of this study has allowed us to propose solutions for the creation of a microclimate favourable to the appropriation of outdoor spaces. The authors finally propose guidelines for the design and rehabilitation of the historic site based on the establishment of links between the site's configuration, microclimatic conditions and users' perceptions.

Part of this study included the analysis of the microclimate of the historic “Bab El Hadid” district of the City of Tlemcen, by developing a questionnaire survey and a numerical simulation validated by measurements of the microclimate the authors made on site. To complete this task, the authors applied the Envi-met 4.1 model during the coldest month of the winter and the hottest month of the summer. Urban parameters are represented at different measurement points characterised by a variability of the sky view factor (SVF).

The results presented in terms of average expected the predicted mean vote (PMV) voting, solar access and air temperature. They show that thermal conditions are directly related to the SVF, the height/width ratio (H/L) of streets as well as the orientation of urban canyons. The points located in the streets facing North–South, present an acceptable performance. Streets shaded by trees with a canyon aspect ratio of between 1.18 and 1.70 reduce heat stress in outdoor spaces. The PMV models discussed provide information on the most appropriate locations for pedestrians. The authors have proposed urban orientations that could limit unfavourable conditions in outdoor spaces. They are useful for architects and urban planners in the design and rehabilitation of historic centres.

In Tlemcen, the microclimate is not taken into account in the design and rehabilitation of urban fabrics. For this specific purpose, the authors want to stress in the research the importance of safeguarding urban heritage through the renewal of the old city and the bioclimatic rehabilitation of its urban spaces.

In cities with high density, heat is often trapped between buildings which increases the frequency and intensity of heat events. Researchers have focused on developing strategies to mitigate the negative impacts of heat in cities. Adopting green infrastructure and cooling pavements are some of the many ways to promote thermal comfort against heat. The purpose of this study is to improve microclimate conditions and thermal comfort levels in high-density living conditions in Seoul, South Korea.

This study compares six design alternatives of an apartment complex with different paving and planting systems. It also examines the thermal outcome of the alternatives under normal and extreme heat conditions to suggest strategies to secure acceptable thermal comfort levels for the inhabitants. Each alternative is analyzed using ENVI-met, a software program that simulates microclimate conditions and thermal comfort features based on relationships among buildings, vegetation and pavements.

The results indicate that grass paving was more effective than stone paving in lowering air temperature and improving thermal comfort at the near-surface level. Coniferous trees were found to be more effective than broadleaf trees in reducing temperature. Thermal comfort levels were most improved when coniferous trees were planted in paired settings.

Landscape elements show promise for the improvement of thermal conditions because it is much easier to redesign landscape elements, such as paving or planting, than to change fixed urban elements like buildings and roads. The results identified the potential of landscape design for improving microclimate and thermal comfort in urban residential complexes.

The results contribute to the literature by examining the effect of tree species and layout on thermal comfort levels, which has been rarely investigated in previous studies.

Due to the predicted global temperature rise and local expansion and densification of cities, Urban Heat Islands (UHI) are likely to increase in the Netherlands. As spatial characteristics of a city influence its climate, urban design could be deployed to mitigate the combined effects of climate change and UHIs. Although cities are already experiencing problems during warm-weather periods, no clear spatial means or strategies are available for urban designers to alleviate heat stress. The paper aims to discuss these issues.

There is a lack of knowledge on cooling effects that can be achieved through urban design in Dutch neighbourhoods. In this paper, the cooling effects of various design measures are compared on the level of urban blocks and neighbourhoods, with a focus on a 1960s neighbourhood in Amsterdam-West. The cooling effects are simulated by means of the microclimate model ENVI-met, here the effects on air temperature and physiological equivalent temperature will be evaluated.

The use of green, and a higher roof albedo in particular, seem to perform well as cooling measures. Combinations of cooling measures do not necessarily result in better performance and might even counteract other cooling effects. However, combinations of measures that lead to an increase in the environmental temperature show the largest heating.

Effects of green roofs and facades are beyond the scope of this study, though future suggestions for this research will be included.

The results add to the body of knowledge in the area of climate design enabling policy makers and designers to estimate the effect of simulated measures in comparable neighbourhoods and thus improve thermal comfort in outdoor spaces.

This research aims to introduce a new methodology for integration between urban design strategies and supervised machine learning (SML) method – by applying both energy engineering modeling (evaluating phase) for the existing green sidewalks and statistical energy modeling (predicting phase) for the new ones – to offer algorithms that help to catch the optimum morphology of green sidewalks, in case of high quality of the outdoor thermal comfort and less errors in results.

The tools of the study are the way of processing by SML, predicting the future based on the past. Machine learning is benefited from Python advantages. The structure of the study consisted of two main parts, as the majority of the similar studies follow: engineering energy modeling and statistical energy modeling. According to the concept of the study, at first, from 2268 models, some are randomly selected, simulated and sensitively analyzed by ENVI-met. Furthermore, the Envi-met output as the quantity of thermal comfort – predicted mean vote (PMV) and weather items are inputs of Python. Then, the formed data set is processed by SML, to reach the final reliable predicted output.

The process of SML leads the study to find thermal comfort of current models and other similar sidewalks. The results are evaluated by both PMV mathematical model and SML error evaluation functions. The results confirm that the average of the occurred error is about 1%. Then the method of study is reliable to apply in the variety of similar fields. Finding of this study can be helpful in perspective of the sustainable architecture strategies in the buildings and urban scales, to determine, monitor and control energy-based behaviors (thermal comfort, heating, cooling, lighting and ventilation) in operational phase of the systems (existed elements in buildings, and constructions) and the planning and designing phase of the future built cases – all over their life spans.

Limitations of the study are related to the study variables and alternatives that are notable impact on the findings. Furthermore, the most trustable input data will result in the more accuracy in output. Then modeling and simulation processes are most significant part of the research to reach the exact results in the final step.

Finding of the study can be helpful in urban design strategies. By finding outdoor thermal comfort that resulted from machine learning method, urban and landscape designers, policymakers and architects are able to estimate the features of their designs in air quality and urban health and can be sure in catching design goals in case of thermal comfort in urban atmosphere.

By 2030, cities are delved as living spaces for about three out of five people. As green infrastructures influence in moderating the cities’ climate, the relationship between green spaces and habitants’ thermal comfort is deduced. Although the strategies to outside thermal comfort improvement, by design methods and applicants, are not new subject to discuss, applying machines that may be common in predicting results can be called as a new insight in applying more effective design strategies and in urban environment’s comfort preparation. Then study’s footprint in social implications stems in learning from the previous projects and developing more efficient strategies to prepare cities as the more comfortable and healthy places to live, with the more efficient models and consuming money and time.

The study achievements are expected to be applied not only in Tehran but also in other climate zones as the pattern in more eco-city design strategies. Although some similar studies are done in different majors, the concept of study is new vision in urban studies.

Living walls (LWs), vegetated walls with an integrated growth layer behind, are being increasingly incorporated in buildings. Examining plant characteristics’ comparative impacts on LWs’ energy efficiency-related thermal behavior was aimed, considering that studies on their relative effects are limited. LWs of varying leaf albedo, leaf transmittance and leaf area index (LAI) were studied for Antalya, Turkey for typical days of four seasons.

Dynamic simulations run by Envi-met were used to assess the plant characteristics’ influence on seasonal and orientation-based heat fluxes. After model calibration, a sensitivity analysis was conducted through 112 simulations. The minimum, mean and maximum values were investigated for each plant characteristic. Energy need (regardless of orientation), temperature and heat flux results were compared among different scenarios, including a building without LW, to evaluate energy efficiency and variables’ impacts.

LWs reduced annual energy consumption in Antalya, despite increasing energy needs in winter. South and west facades were particularly advantageous for energy efficiency. The impacts of leaf albedo and transmittance were more significant (44–46%) than LAI (10%) in determining LWs’ effectiveness. The changes in plant characteristics changed the energy needs up to ca 1%.

This study can potentially contribute to generating guiding principles for architects considering LW use in their designs in hot-humid climates.

The plant characteristics’ relative impacts on energy efficiency, which cannot be easily determined by experimental studies, were examined using parametric simulation results regarding three plant characteristics.

This study aims to compare the local climate characteristics of Angkor Wat, Borobudur and Prambanan parks and determine effective strategies for mitigating thermal conditions that could suit Borobudur and Angkor Wat.

The study employed local climate zone (LCZ) indicators and ten-year historical climate data to identify similarities and differences in local climate characteristics. Satellite imagery processing was used to create maps of LCZ indicators. Meanwhile, microclimate models were used to analyze sky view factors and wind permeability.

The study found that the three tropical large-scale archaeological parks have low albedo, a medium vegetation index and high impervious surface index. However, various morphological characteristics, aerodynamic properties and differences in temple stone area and altitude enlarge the air temperature range.

Based on the similarities and differences in local climate, the study formulated mitigation strategies to preserve the sustainability of ancient temples and reduce visitors' heat stress.

The local climate characterization of tropical archaeological parks adds to the number of LCZs. Knowledge of the local climate characteristics of tropical archaeological parks can be the basis for improving thermal conditions.

This paper reviews extant studies on bioclimatic architecture with a view of revealing the focus areas of past studies and mapping out future research directions useful in achieving building energy efficiency.

A mixed-method systematic review that integrates quantitative and qualitative analysis was adopted. The bibliographic data were extracted from the Scopus database, and a scientometric analysis was conducted to analyse the data quantitatively. Qualitative content analysis is then presented, which provided a basis for mapping out trends and gaps in current knowledge.

It is observed that there has been a rise in the number of studies on bioclimatic architecture over the last two decades. Past studies have focused on sustainability, building performance simulation, building climatology and energy use, solar energy applications and passive cooling. Artificial intelligence, algorithm coupling and acoustic comfort were some of the emerging areas discovered in this study.

The study reveals research gaps that researchers can investigate.

The information provided can help the building industry stakeholders in decision-making. It serves as a guideline for maximising the potential benefits of adopting bioclimatic designs in the building industry. Furthermore, it provides references that aid policy formulation for government agencies and corporate organisations.

The study fills the literature gap caused by the need for a holistic literature review that relates bioclimatic architecture and its energy efficiency implications. It is also the first study on bioclimatic architecture that adopts a mix of scientometric and qualitative analysis for analysing past studies on bioclimatic architecture.