Impact of Courtyard Microclimate on Building Thermal Performance Under Hot Weather Conditions: A Review

Abstract

The increasing frequency of extreme heat events poses significant challenges to buildings in terms of escalating thermal stress, while courtyards, as a traditional passive cooling strategy, demonstrate considerable potential in improving building thermal performance and in energy savings for cooling. Although existing studies have revealed the role of courtyards in enhancing their internal microclimate, an in-depth understanding of how design parameters regulate the microclimate and thereby affect the thermal performance of adjacent buildings remains limited, constraining their effective application in coping with extreme heat. This study conducts an exploration of relevant research aiming to elucidate the mechanisms of courtyard microclimate regulation, the quantitative methods employed, and effective design strategies in addressing high temperatures. The findings indicate that courtyards influence the building thermal performance through four mechanisms: solar radiation control, airflow organization, evaporative cooling, and thermal buffering. Their effectiveness depends on the optimized combination of geometry, material properties, and landscape configuration. Moreover, different quantitative methods exhibit notable differences in scale, accuracy, and applicability. Finally, based on the identified key factors and their interactions, this study proposes optimization pathways to bridge the gap between design expectations and practical outcomes, thereby providing both a theoretical framework and practical guidance for advancing the scientific application of courtyards in enhancing building thermal performance and energy efficiency.

1. Introduction

Climate change has emerged as one of the most pressing challenges facing human society in the 21st century. According to the Intergovernmental Panel on Climate Change (IPCC), extreme weather events—such as floods, droughts, hurricanes, and heatwaves—are occurring with increasing frequency on a global scale [1]. Among these, extreme heat events have become particularly prominent. Numerous records indicate a significant upward trend in the intensity, frequency, and duration of such events in recent years [2,3]. For instance, in 2019, a summer heatwave caused temperatures in countries like the Netherlands and the United Kingdom to rise 4.7 °C above the seasonal average [4]. During the 2021 heatwave in western North America, Canada recorded an unprecedented temperature of 49.6 °C [5]. In 2022, China experienced a prolonged heatwave lasting 79 days, during which 361 weather stations broke historical records [6]. In 2023, persistent high-temperature events occurred in Italy, with Milan, reaching an average daily temperature of 32.98 °C, the highest recorded since 1763 [7].

More than half of the global population is clustered in urban areas, making high temperatures in urban environments particularly problematic due to the urban heat island effect (UHI) caused by high building densities, insufficient green space coverage, and anthropogenic heat emissions [8]. The superposition of global warming and the UHI effect not only reduces thermal comfort [9], but also significantly increases energy consumption and carbon emissions connected to cooling systems, creating a vicious cycle that further intensifies the UHI effect while contributing to global climate change [10], exposing urban dwellers to a higher risk of heat stress and potential health hazards [11].

In response to the escalating challenge of urban heat, the development and implementation of effective passive cooling strategies have become increasingly important to reduce the energy demand while ensuring suitable (or at least acceptable) comfort conditions [12]. Compared to active cooling systems, passive approaches offer advantages such as low energy consumption, cost-effectiveness, and environmental sustainability, making them a focal point in the pursuit of urban sustainability [13].

The implementation of passive cooling strategies encompasses various aspects, including material selection [14], envelope optimization [15], and architectural spatial configuration [16]. Among these, the design of building spatial forms offer a unique advantage in shaping favorable microclimates, as it can influence solar radiation exposure, wind flow, and thermal exchange processes through geometric arrangement and spatial organization [17]. Among the many spatial strategies, courtyards play a significant role in mitigating climatic fluctuations due to their distinctive spatial configuration and capacity for internal environmental regulation [18].

Courtyards are typically defined as open-to-sky spaces enclosed or semi-enclosed by buildings or walls [19]. Their design is deeply influenced by climatic conditions and local cultural traditions, and they have been widely adopted across diverse climate zones such as the Mediterranean, the Middle East, and Asia for centuries [20]. In cold climates, courtyards can provide shelter from wind and enhance solar heat gain [21]; in hot climates, they help reduce temperatures in outdoor spaces as well as adjacent indoor environments [22]. This capacity to mediate external climatic fluctuations makes courtyards one of the most effective passive strategies for improving building microclimates.

A substantial body of research has explored how courtyard geometry, surface materials, and landscape elements contribute to shaping courtyard microclimates [23]. Studies have shown that courtyard geometry directly influences solar heat gain and natural ventilation within the space [24,25]; high-albedo surfaces can effectively reduce solar absorption and enhance the courtyard’s cooling potential through increased heat reflection [26,27]; and well-planned vegetation layouts can lower surface temperatures and increase air humidity via shading and evapotranspiration [28,29]. These mechanisms not only improve the courtyard’s microclimate but also influence the thermal performance of adjacent buildings.

However, existing review studies predominantly focus on the courtyard microclimate itself. Zhu et al. [30] reviewed the effects of courtyard geometry and orientation on microclimate optimization and proposed design strategies tailored to various climatic conditions. Liu et al. [31] further examined how surface materials and landscape elements affect outdoor thermal comfort, emphasizing the importance of climate-responsive design standards that are sensitive to local conditions; Zamani et al. [17] synthesized research on courtyard microclimates and thermal functions, highlighting the potential of courtyard design elements to enhance the energy efficiency of surrounding buildings, and calling for further investigation into their coupled thermal performance. Despite these contributions, there remains a lack of in-depth understanding regarding how and to what extent courtyard design parameters influence the thermal performance of adjacent buildings through summer microclimate regulation. In particular, there is a notable gap in the literature concerning the trends, influencing factors, and methodological approaches related to the impact of courtyard design parameters on building thermal performance under summer conditions across different climatic regions.

Bridging these knowledge gaps is crucial. A deeper understanding of the existing research findings and future research opportunities can provide scientific support for optimizing and retrofitting sustainable buildings, by effectively exploiting the resource that courtyards can represent. This, in turn, can advance energy-saving practices, improve indoor thermal comfort, and enhance buildings’ passive adaptation capacity in extreme heat scenarios.

Therefore, the objective of this study is to review and analyze the current state and trends in courtyard-related building environmental research, aiming to answer the following three research questions:

(i) How does courtyard affect building thermal performance through their microclimatic effects?

(ii) Considering the link between courtyard microclimate and the indoor thermal performance of the surrounding buildings, what methods have been used in existing studies to quantify such impacts?

(iii) Which courtyard design strategies have been demonstrated to mitigate the impact of extreme heat?

Finally, the results of this study provide a comprehensive perspective for understanding how courtyard design can enhance the thermal performance of buildings through microclimatic effects, providing key theoretical support and valuable insights for building designers, researchers, and practitioners in combating climate change, enhancing building resilience, and promoting sustainable development.

2. Materials and Methods

This exploratory study preferentially looks at scientific analysis reported in the literature which is browsed and scanned adhering to the PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Relevant publications were retrieved from Scopus and Web of Science (WoS), which are recognized as the most authoritative and comprehensive databases in the field of architecture and building performance. These platforms are maintained and updated by professional institutions, ensuring the high impact and reliability of the data extracted [32].

The adopted methodology comprises four stages: the first stage involves constructing search strings based on predefined search criteria and scope, followed by screening the literature according to strict eligibility standards; the second stage conducts quantitative analysis to present existing findings and their spatial–temporal distribution within the research field; the third stage performs qualitative analysis to interpret the overall landscape and development trends of the field; the fourth stage addresses the three core questions posed by this review, analyzes current research limitations, and identifies future directions for studies on courtyard building thermal performance. Figure 1 illustrates the general workflow of the research methodology.

The PRISMA process itself consists of four phases: identification, screening, eligibility, and inclusion. Relevant data was extracted and compiled into an Excel spreadsheet. Figure 2 presents the workflow and the number of records processed at each phase.

To address the aforementioned research questions, the following search criteria were established:

• Scope: Building thermal performance and/or energy demand.
• Subject: Courtyard buildings.
• Scenario: Hot climates, summer conditions, or extreme heat events.

To ensure the comprehensiveness of the literature search, an iterative testing method was employed to optimize the combination of search terms. The selection of keywords was guided by two core criteria: the adequacy of the number of results and the relevance to the research topic. Through this filtering process, overly broad terms that yielded excessive generalized results, as well as overly narrow terms that significantly limited the number of retrieved records, were excluded.

Accordingly, the final string is as below: (“thermal performance” OR “thermal environment” OR “thermal comfort” OR “cooling” OR “energy demand” OR “energy consumption”) AND (“courtyard*” OR “patio*”) AND (“summer” OR “hot*” OR “heat” OR “warm” OR “overheating” OR “extreme climate*” OR “climate change”)

After determining the search string, the complete string was searched by topic (title, keywords, and abstract).

Preliminary analysis revealed a rapid growth in related studies starting from 2015. Based on this observation and to ensure the reliability of the literature search, the following filters were applied to narrow the search scope:

• Publication year range: 2015–2025
• Language: English
• Document types in WoS and Scopus: Articles, review articles, and book chapters
• Research areas: Differences between WoS and Scopus are detailed in

  Table 1. Selected categories in WoS and Scopus databases.

  Database	Categories
  Web of Science	Construction Building Technology
  	Engineering Civil
  	Environmental Sciences
  	Energy Fuels
  	Green Sustainable Science Technology
  	Environmental Studies
  	Engineering Environmental
  	Thermodynamics
  	Architecture
  	Engineering Multidisciplinary
  	Urban Studies
  Scopus	Engineering
  	Environmental Science
  	Energy

  .

The search was conducted between April and June 2025; papers published after the end of June 2025 are not included.

A total of 604 records were retrieved from WoS and Scopus. To remove duplicates, the results were imported into Excel and subjected to automatic deduplication, identifying 200 duplicate records. An additional 28 duplicates were manually removed upon review, leaving 376 records for the screening phase.

To ensure the relevance and quality of the sample literature, strict evaluation criteria were established. Based on these criteria, the records were categorized and labeled as “included” or “excluded” according to predefined standards, as shown in

Table 2. Reasons for inclusion and exclusion criteria.

Reason Number	Content	Reason
R1	Scale	The scope of the study is too broad or extends beyond the building scale, such as focusing on urban microclimate or community-scale environments.
R2	Subject	The core research focus is not on courtyards or their design parameters, for instance, studies centered on green roofs, sunspaces, atrium, or other microclimate interventions are excluded.
R3	Scenario	The study is not focused on high-temperature contexts, such as examining winter heating, annual energy consumption without clearly distinguishing summer performance, or unrelated seasonal conditions.
R4	Scope	The primary aim is not the impact of courtyards on building thermal performance or energy use, e.g., studies focusing only on outdoor comfort, courtyard aesthetics or social functions, or building acoustics or lighting are not considered.
R5	Access	The keywords, abstract or full text are unavailable.
R6	Field	The content belongs to unrelated fields or disciplines, such as biogas reactors, multi-source heat pumps, or agricultural greenhouses.

.

Ultimately, 44 publications were included for in-depth analysis and clustered according to research themes (see

Table A1. Classification of Included Studies.

4.1. Key Mechanisms of Courtyard Effects on Building Thermal Performance

Xu et al., 2018 [20]; Salameh 2024 [36]; Domínguez-Torres and Domínguez-Delgado 2024 [37]; M’Saouri El Bat et al., 2023 [38]; Zhang et al., 2024 [39]; Sun et al., 2023 [40]; Diz-Mellado et al., 2023a [41]; He et al., 2022 [42]; Albaik and Muhsen 2025 [43]; Toe and Kubota 2015 [44]; Forouzandeh 2022 [45]; Darvish et al., 2021 [46]; Chi et al., 2022 [47]; Zhou et al., 2024 [48]; He and Osmond 2024 [49]; Bian et al., 2022 [50]; Wu et al., 2024 [51]; Yao et al., 2020 [52]; Palomo Amores et al., 2025 [53]; Freewan and Khatatbeh 2023 [54]; Gomaa et al., 2024 [55]; Sun et al., 2024 [56]; Diz-Mellado et al., 2023b [57]; Chidiadi and Taki 2025 [58]; Zamani et al., 2019 [59]; Lizana et al., 2022 [60]; Gamage et al., 2017 [61]

4.2. Assessment Methods for Courtyard Building Thermal Performance

Zamani et al., 2018 [17]; Tabadkani et al., 2022 [23]; Salameh 2024 [36]; Toe and Kubota 2015 [44]; Darvish et al., 2021 [46]; Palomo Amores et al., 2025 [53]; Sun et al., 2024 [56]; Lizana et al., 2022 [60]; ALshabanat and Omer 2023 [62]; Kubota et al., 2017 [63]; Yan et al., 2024 [64]; Nugroho et al., 2020 [65]; Chohan et al., 2024 [66]; Abdallah 2022 [67]; López-Cabeza et al., 2022 [68]; Zhao et al., 2025 [69]; Salameh and Touqan 2024 [70]

4.3. Courtyard Design Strategies for Extreme Heat Mitigation

Hao et al., 2019 [18]; Domínguez-Torres and Domínguez-Delgado 2024 [37]; M’Saouri El Bat et al., 2023 [38]; Diz-Mellado et al., 2023a [41]; He et al., 2022 [42]; Forouzandeh 2022 [45]; Darvish et al., 2021 [46]; Gomaa et al., 2024 [55]; Sun et al., 2024 [56]; Diz-Mellado et al., 2023b [57]; Chidiadi and Taki 2025 [58]; Zamani et al., 2019 [59]; Kubota et al., 2017 [63]; Almahmoud et al., 2024 [71]; Erdemir Kocagil and Koçlar Oral 2016 [72]; Razavian et al., 2023 [73]; Sun et al., 2021 [74]; Li et al., 2019 [75]

). All subsequent analyses were based on this specific dataset.

In the second stage of the review, the 44 selected records were subjected to bibliometric analysis using Bibliometrix (v5.0.1), focusing on their temporal distribution, geographical distribution, and document types. Bibliometrix, an open-source R package (v4.5.1) specifically designed for scientific mapping and quantitative research evaluation, is recognized for its reliability and applicability [33]. In the third stage, CiteSpace (v6.3.R1) was employed to analyze term co-occurrence in titles and abstracts. Developed on the Java platform, CiteSpace is a tool specialized in visualizing knowledge domains and is effective in revealing topic evolution, emerging trends, and clustering features within specific research fields, thereby providing a foundation for further analysis [34]. The 44 complete records (including authors, titles, abstracts, keywords, and journal sources) were imported into CiteSpace for processing. The analysis parameters were configured with a time span from 2015 to 2025 and annual time slices to capture temporal evolution of research themes, node type set to “keywords” to focus specifically on terminological relationships, and “pruning the merged networks” enabled to eliminate weak connections and highlight dominant thematic clusters.

In the fourth stage, both quantitative and qualitative results were integrated with in-depth analysis to address the proposed research questions, analyze current research limitations, and provide recommendations for the future development of courtyard-related building thermal performance studies.

3. Results

3.1. Quantitative Analysis

Figure 3 illustrates the publication trend in courtyard building thermal performance research from 2015 to 2025. Over this period, the number of publications increased substantially, with a marked rise after 2022, reaching a peak of 12 papers in 2024. This reflects growing scholarly focus on courtyard thermal performance amid escalating climate concerns and building energy efficiency demands. The notable decline in 2025 may be attributed to the incompleteness of the data collection period (up to June).

Figure 4 presents the geographical distribution of publication contributions, with research activity primarily concentrated in Asia, Europe, and the Middle East, while output from other regions remains limited. The connecting lines indicate international collaboration between research institutions, with thicker lines representing stronger collaborative relationships. China ranks first with 30 publications, which is closely related to the widespread use of courtyards in traditional Chinese architecture and the rapid growth of research on green building and sustainable development in recent years. The United Kingdom (12 publications) and Spain (10 publications) follow, reflecting the high level of research activity in European countries on building energy efficiency and climate-adaptive design. In addition, notable contributions have also been made by Iran (9 publications), Australia (5 publications), and Malaysia (5 publications), most of which are located in hot climate regions where the demand for research on courtyard cooling strategies is particularly urgent or in countries where the topic is a priority in research.

Figure 5 presents the top ten journals by publication volume. This distribution reflects the field’s span across multiple disciplines, including the built environment, energy efficiency, sustainability, and building simulation.

Regarding the document types in the results, according to the text output, among the 44 samples, 42 were “Articles”, and 2 were “Reviews”.

3.2. Qualitative Analysis

3.2.1. Keyword Co-Occurrence Analysis

A co-occurrence analysis of keywords in the field of courtyard building thermal performance was conducted with a threshold set at 6, and a co-occurrence network was generated. A total of 159 nodes and 492 links were obtained. The size of each node reflects the frequency of the keyword in the sample literature, while the thickness of the purple border indicates betweenness centrality, which measures the “bridging” role of a keyword within the network. A thicker border denotes higher betweenness centrality, suggesting that such nodes often represent cross-disciplinary and widely recognized hub concepts, pointing to potential research frontiers or critical connections within existing studies [35].

As shown in Figure 6, the most frequent keyword is “thermal comfort”, followed by “buildings”, “design”, “impact”, “comfort”, “natural ventilation”, “energy consumption”, “passive cooling”, and “climate”.

“Thermal comfort,” as the most frequently occurring keyword, together with “comfort,” indicates that occupant thermal comfort is the central evaluation objective in this field of research. “Buildings” and “design” directly point to the research’s application carrier and intervention approach. Keywords such as “energy consumption”, “passive cooling”, “climate”, “impact”, and “natural ventilation” reveal three main dimensions of this field: energy optimization, passive cooling strategies, and climate-adaptive design. These research directions all focus on improving the thermal performance of courtyard buildings through passive design under specific climatic conditions, thereby achieving the dual goals of energy conservation and enhanced comfort.

Further analysis of keyword centrality reveals the knowledge structure of the field and potential interdisciplinary research frontiers. The top 20 keywords are listed in

Table 3. List of keyword co-occurrence.

No.	Freq	Centrality	Keywords
1	8	0.7	comfort
2	3	0.43	energy performance
3	2	0.27	architectural design
4	12	0.25	buildings
5	7	0.25	energy consumption
6	4	0.22	cfd simulation
7	4	0.21	hot humid climate
8	2	0.2	courtyard house
9	3	0.18	courtyard building
10	16	0.15	thermal comfort
11	7	0.13	passive cooling
12	1	0.13	arid climate
13	3	0.13	model
14	3	0.12	optimization
15	7	0.11	climate
16	7	0.1	energy
17	2	0.09	climate responsive design
18	1	0.09	different climatic regions
19	2	0.08	climate change
20	4	0.08	dwellings

.

The high centrality of “comfort” and “thermal comfort” further confirms their core status. Whether in courtyard design, building performance, or simulation methods, the ultimate concern is consistently linked to human comfort. “Energy performance” and “energy consumption” indicate that research on courtyard thermal performance is closely linked to energy optimization, representing a crucial pathway for building sustainability. Methodological terms such as “CFD simulation” and “optimization” highlight the importance of computational modeling and optimization techniques as key tools for quantitative evaluation and the pursuit of optimal solutions. “Hot humid climate”, “arid climate”, and “climate” underscore that climatic conditions are critical factors in courtyard research, requiring corresponding design strategies for different climate zones.

3.2.2. Cluster Analysis

CiteSpace’s automated algorithm was employed to conduct cluster analysis of the keyword network. Cluster quality was assessed using the modularity value (Q) and the mean silhouette value (S), where Q > 0.3 indicates a reasonable structure and S > 0.7 indicates high reliability. In this study, Q = 0.677 and S = 0.906, both exceeding the standard thresholds, suggesting that the clustering results exhibit significant modularity and high homogeneity, thereby confirming the reliability of the analysis.

A total of eight clusters were obtained and ordered by size from #0 to #7 according to CiteSpace’s naming system, with the largest cluster designated as #0. After screening, seven valid clusters were retained, as shown in Figure 7.

Based on the clustering analysis, three major research directions in the field of courtyard microclimate and building thermal performance were identified.

#0 (sustainable design strategy) and Cluster #1 (building retrofitting) together constitute the strategic framework for optimizing the energy consumption and thermal performance of courtyard buildings, reflecting the transition from theoretical design to engineering practice. Sustainable design concepts regulate the courtyard microclimate through natural ventilation, vegetation configuration, and envelope optimization, while parametric tools enable their rapid application in retrofitting existing buildings, making the courtyard microclimate an important pathway for energy-efficient renovation.

#2 (ventilation) and Cluster #6 (climate responsive design) represent the integration of technical depth and design breadth. Numerical simulations provide a precise analytical basis for courtyard ventilation and heat transfer processes, while climate-responsive design translates these technical outcomes into systemic strategies such as urban heat island mitigation and solar radiation control, thereby forming a complete chain from technical analysis to practical application.

Clusters #3 (traditional dwelling), #4 (hot–humid climate), and #5 (air-well courtyard) embody the regional wisdom and modern adaptation of courtyard architecture under specific climatic conditions. Research on traditional dwellings and vernacular architecture reveals the thermal regulation mechanisms of courtyard microclimates in different climatic contexts, providing historical insights for contemporary courtyard design.

3.2.3. Timeline Analysis

The keyword timeline presented in Figure 8 illustrates the historical development trends in this field within the selected time frame.

• Since 2015, the central role of “thermal comfort” has established building thermal comfort as the most critical driving factor in courtyard research.
• Between 2017 and 2021, the increasing weight of “buildings” and “energy consumption” reflected a shift in research focus from courtyard microclimate characteristics to their impact on overall building thermal performance, with strong attention to energy consumption. The concentrated emergence of “CFD simulation”, “microclimate”, and “optimization” signaled the widespread application of numerical simulation techniques in the analysis of courtyard microclimates and thermal performance.
• Since 2022, research trends have focused on extreme climate adaptation. The emergence of “climate adaptive”, “climate resilient design”, “courtyard microclimate”, and “architectural design” indicates that courtyard microclimates are increasingly regarded as key design strategies for enhancing building climate adaptability and resilience. “Indoor thermal comfort”, “multi-zone airflow modeling”, and “building performance simulation” reflect a methodological shift toward refined indoor thermal performance simulation to address the growing risk of indoor overheating.

3.2.4. Keyword Bursts

Burst term detection was conducted using CiteSpace (minimum duration = 2 years, γ = 0.3). Based on the Kleinberg algorithm, the top 15 keywords were identified. As shown in Figure 9, the cyan bars represent the full lifecycle of terms, while the red bars indicate the burst periods. The strength values reflect the degree of frequency fluctuation of keywords within specific time windows.

• 2015–2017: Passive cooling and vernacular architecture marked the exploration of passive technologies in traditional architecture within this field.
• 2017–2018: Natural ventilation and strategy indicated a growing focus on the complex wind environments of courtyards and surrounding buildings, as research shifted from observational phenomena to strategic development.
• 2019–2021: Numerical simulation and optimization reflected a shift toward quantitative analysis and performance optimization, with increasing reliance on advanced computational simulation techniques.
• Post-2021: Climate and environment highlighted the strengthening association between courtyard design research and broader climate and environmental issues.

4. Discussion

4.1. Key Mechanisms of Courtyard Effects on Building Thermal Performance

The optimization of thermal performance has long been a central issue in the field of courtyard architecture. Based on the comprehensive analysis of the 44 selected publications, courtyards influence the thermal performance of adjacent buildings primarily through four mechanisms identified from the existing research: solar gain control, airflow regulation, evaporative cooling, and thermal buffering.

4.1.1. Solar Gain Control

Solar gain control represents the core mechanism by which courtyards affect building thermal performance. A study conducted in the UAE demonstrated that optimized geometric configurations can effectively alter the extent and duration of façade shading during critical summer periods through mutual shading created by courtyard geometry [36]. At the same time, highly reflective envelope materials and ground surfaces not only reduce direct solar absorption but also lower radiative transfer to adjacent buildings [37]. Numerous studies have confirmed the effectiveness of geometric parameters and spectral properties of materials in reducing radiative heat gain [38,39,40,41,42,43,44,45].

However, further analysis reveals significant complexity. For example, Forouzandeh’s study found an interaction effect between material reflectance and courtyard geometry, with shallow courtyards showing greater sensitivity to changes in reflectivity [45]. While increasing reflectivity helps reduce primary solar absorption, excessively high reflectance may also intensify diffuse reflection within the courtyard. In this regard, the introduction of vegetation not only provides dynamic regulation but also creates synergistic effects with other shading strategies [46]. By generating multilayered and overlapping shading patterns, vegetation differentiates between direct and diffuse radiation, thereby enhancing overall shading performance [47]. Despite these insights, most studies still treat the issue as a static geometric problem. Such simplification may lead to diminishing returns under real-world conditions and even pose risks of design failure.

4.1.2. Airflow Regulation

Airflow regulation relies on two driving forces—buoyancy and wind pressure—to promote natural ventilation [48]. The former arises from buoyant forces generated by temperature differences between the courtyard and its surroundings [49,50], while the latter results from pressure differences caused by interactions between external wind fields and courtyard geometry, leading to flow separation and vortex formation [51]. Existing research has developed in-depth understanding of each mechanism individually. For example, Yao et al. enhanced indoor air exchange efficiency through the courtyard’s cooling storage effect and buoyancy-driven flow [52], while Palomo Amores et al. introduced cool air by exploiting pressure differences between courtyards and adjacent streets [53], both achieving significant cooling effects.

It is noteworthy, however, that the temporal variability and directional differences in these two driving forces often lead to reduced ventilation rates or airflow turbulence. Moreover, the influence of geometric parameters is not always synergistic and may even produce opposing outcomes [54]. Although some studies have proposed strategies integrating both driving forces [20], such recommendations are largely based on steady-state assumptions and fixed wind directions, and their applicability under real-world conditions of fluctuating wind speeds and directions requires further validation.

4.1.3. Evaporative Cooling

Evaporative cooling is realized through two distinct pathways: plant transpiration and water evaporation. These mechanisms differ fundamentally in their regulation. Plant transpiration, as an active biological process, intensifies with rising temperatures and aligns well with building cooling demand [55], though its effectiveness is constrained by water availability. Water evaporation, governed by a steady physical process, can provide continuous cooling but is strongly influenced by ambient humidity. Under low-humidity conditions, cooling is pronounced, but with increasing humidity, the marginal effect diminishes [56]. In near-saturation states, enlarging water surfaces or increasing water flow may not yield additional cooling and could instead exacerbate discomfort due to excessive humidity [44]. Consequently, regional climatic characteristics are particularly critical in such designs.

4.1.4. Thermal Buffering

The thermal buffering mechanism reflects the advantage of thermal inertia in courtyard spaces and materials, stabilizing building thermal environments by delaying temperature fluctuations [57]. Its effectiveness has been confirmed in related studies. For instance, Chidiadi and Taki noted that the heat storage and release cycle of high thermal mass materials can flatten peak temperatures [58], while Zamani found that enclosed courtyard forms further reduce direct heat exchange and create a more stable microclimate [59]. Nevertheless, some studies have reported the duality of thermal buffering: while it lowers peak daytime temperatures, it may also prolong nighttime heat retention [60]. This finding has important implications for design practice, underscoring the need to match material thermal properties and courtyard configurations with local diurnal temperature variations, and to combine them with strategies such as nighttime ventilation cooling, in order to avoid excessive heat accumulation caused by over-reliance on thermal inertia [61].

4.2. Assessment Methods for Courtyard Building Thermal Performance

Quantifying the coupled relationship between courtyard microclimate and building thermal performance remains a central challenge in evaluating strategy effectiveness. Research methods have evolved from field measurements to integrated validation approaches combining numerical simulation with experimental verification [17,23,62].

Extensive studies have attempted to capture the real and complex on-site conditions through field measurements to provide reliable data benchmarks [44,63,64]. However, two core challenges remain. First, the microclimatic heterogeneity of courtyard spaces requires high-density sensor networks to accurately characterize their thermal environment [65]. In practice, due to cost and technical limitations, the density of measurement points often fails to meet the requirement for spatial continuity, potentially overlooking critical temperature gradients and airflow features. Second, the evaluation of courtyard thermal performance requires sufficiently long time-series data. Yet, existing studies often rely on short-term measurements. For example, Yan et al. inferred overheating risks during heat waves based on only two days of field data [64], raising concerns about the reliability of extrapolating results across mismatched temporal scales.

Numerical simulation methods provide more efficient and controllable research tools, compensating for the limitations of field measurements [66]. Current research mainly employs three categories of tools. Computational Fluid Dynamics (CFD) tools excel in analyzing complex airflow organization and convective heat transfer; for instance, Sun et al. used Fluent to evaluate ventilation strategies in a courtyard evaporative cooling system [56]. Microclimate models are suitable for coupling multiple outdoor environmental factors; Abdallah employed such models to quantify the thermal impact of courtyard vegetation [67]. Building Performance Simulation (BPS) tools focus on energy consumption and thermal performance evaluation; Lizana et al. integrated multi-node outdoor conditions into TRNSYS to analyze the influence of microclimates on indoor thermal performance [60]. However, each method has specific limitations. CFD accuracy depends heavily on boundary conditions and turbulence model selection [53]. Microclimate models face constraints in resolution and physical process representation under complex geometries and extreme climates [68]. BPS often assumes uniform external environments, making it difficult to accurately reflect the dynamic courtyard–indoor interactions [69].

To address these challenges, many studies have incorporated CFD or microclimate model outputs as boundary conditions for building simulations [36,46,53,70]. Although theoretically more rigorous, this study finds that modeling complexity, high computational costs, and unavoidable information loss remain significant issues [68]. More importantly, most approaches adopt only unidirectional data transfer, with limited consideration of the feedback effects of building heat emissions on the courtyard microclimate. This constrains the accurate prediction of the actual thermal performance of courtyard–building coupled systems.

4.3. Courtyard Design Strategies for Extreme Heat Mitigation

The increasing frequency of extreme heat events places higher demands on building cooling strategies, prompting renewed attention to the potential of courtyards in optimizing building thermal performance. Existing studies have primarily focused on three dimensions: geometric configuration, material properties, and landscape design.

4.3.1. Geometric Configuration Strategies

The aspect ratio (AR) of courtyards, generally referred to as the ratio of height to width, demonstrates a clear trade-off in thermal performance regulation. High-AR courtyards indeed exhibit cooling and energy-saving potential [38]. For example, in a study conducted in Spain, an enclosed courtyard with AR = 2.12 maintained indoor operative temperatures within 27 °C and achieved a 20.5% reduction in energy consumption [57]. The energy-saving effect was particularly pronounced in ground-floor spaces [41]. However, overly deep and enclosed courtyards may restrict air exchange within the courtyard, resulting in a “cool but stagnant” indoor environment [63]. This issue of insufficient ventilation is especially critical in humid conditions. As residential spaces, courtyards must promote air circulation to facilitate sweat evaporation and prevent excessive humidity, even though this may slightly increase indoor temperatures.

Another set of studies has examined the impact of courtyard orientation on building energy consumption. Global sensitivity analysis revealed that orientation influenced cooling energy use in square and rectangular courtyards by as much as 37% and 81%, respectively, underscoring its significance as a design parameter [42]. Further research indicated that west-facing courtyards exhibited the lowest cooling loads, whereas south-facing courtyards incurred the highest energy consumption due to prolonged solar exposure in summer [71]. Moreover, orientation design is evolving into a coordinated optimization of orientation, function, and seasonality [59,72]. For instance, Razavian et al. achieved an additional 38.4% energy savings by aligning courtyard orientation with indoor functional layout and thermal variations [73]. This demonstrates that the thermal optimization of courtyards depends not only on their geometric characteristics but also on their integration with usage patterns and climatic conditions.

4.3.2. Material Performance Strategies

From a material selection perspective, both surface reflectivity and thermal capacity play critical roles. Studies have shown that increasing courtyard surface reflectance from 0.1 to 0.9 can reduce façade sol-air temperatures by 81.54 °C [45]. Another study confirmed that ultra-emissive paint lowered courtyard temperatures by 4 °C and reduced indoor thermal loads by 69.85% [37]. However, high-reflective materials face degradation issues, as their performance diminishes over time due to aging and pollution. By contrast, research in Nigeria demonstrated that compressed earth blocks, with their higher thermal capacity and lower thermal transmittance, reduced peak indoor temperatures by 1.19 °C [58]. It should be noted, however, that high-thermal-mass materials such as stone blocks may exacerbate indoor overheating if they excessively store heat during the day and fail to dissipate it effectively [18].

4.3.3. Landscape Design Strategies

Beyond architectural parameters, courtyard landscaping also exerts a significant influence on thermal performance. Studies have shown that both vegetation coverage and height are positively correlated with cooling effects, with an increase in coverage from 20% to 60% yielding a 19.2% reduction in cooling energy consumption [55], while moderate increases in vegetation height further enhanced cooling performance [74]. In terms of planting strategies, dense arrangements of coniferous trees and the application of vertical greening techniques both demonstrated strong energy-saving potential [46,75]. Despite these benefits, vegetation-based strategies are constrained by practical conditions. In arid environments, for example, shading effects are weakened by water stress, and the additional water demand may offset some of the energy benefits. Furthermore, while dense vegetation can enhance shading and evapotranspiration cooling, it may also obstruct beneficial natural ventilation, highlighting the inherent trade-offs among different cooling strategies.

The use of water features also presents complex characteristics. For example, Sun et al. found that under single-sided ventilation, a water-spraying system achieved an overall temperature reduction of 2.06 °C, though spatial variations were significant, with some areas experiencing up to 8.25 °C cooling alongside a 20.27% rise in humidity [56]. These finding highlights that the distribution of cool and humid air is highly dependent on airflow organization, suggesting that practical applications should integrate water-based strategies with ventilation design to optimize spatial thermal and humidity uniformity.

5. Conclusions

This study analyzed the literature on courtyard buildings, deepening the understanding of courtyard design in mitigating building overheating and reducing energy consumption. The research reveals that the field has evolved from traditional experience-based approaches to a multidisciplinary, climate-adaptive design framework, with core topics centered on thermal comfort and building energy performance.

Based on the analysis, the main conclusions are as follows:

• Thermal performance regulation mechanisms: Courtyard buildings improve the microclimate through four mechanisms—solar gain control, airflow organization, evaporative cooling, and thermal buffering. These mechanisms do not function as simple linear superpositions but rather interact to form a dynamic balance that collectively determines the overall thermal performance of courtyards.
• Research methods and scale selection: The choice of methods for quantifying such impacts should depend on specific research objectives. When exploring fundamental mechanisms, in-depth analysis using a single method is often more effective than complex couplings, whereas for practical applications, comprehensive evaluation and uncertainty analysis are more critical. Different analytical scales reveal significantly different insights, requiring researchers to strike a balance between methodological precision and practical feasibility.
• Integrated design strategies: Effective courtyard design must reconcile internal conflicts among mechanisms, adapt to the specific requirements of different climatic conditions, and employ multi-strategy coordination to avoid overall performance degradation caused by over-optimization of a single strategy. This requires designers to move beyond traditional segmented optimization and adopt an integrated design approach.

The findings are based on a sample of 44 selected publications and should not be generalized to the entire field of courtyard building environment research. Additionally, the analysis is primarily based on published English-language literature, which may not comprehensively cover emerging technologies, innovative strategies, or localized research outcomes in non-English contexts. In addition, since this study mainly focuses on thermal performance, other environmental benefits of courtyards (e.g., acoustics, daylighting) and humanistic dimensions (e.g., privacy, social interaction) have received relatively less attention. These limitations provide clear directions for future improvement.

Future research should move beyond conventional energy consumption assessments, focusing on the resilience of courtyard strategies and the analysis of critical thresholds under extreme heat events to enhance the adaptability of building systems under compound disturbances. Moreover, incorporating occupant adaptive behaviors and subjective thermal perception into quantitative evaluation models is necessary to achieve human-centered design optimization. In addition, constructing a comprehensive life-cycle assessment framework that includes economic costs, maintenance requirements, and environmental impacts will ensure the long-term sustainability and effectiveness of courtyard design strategies.

In summary, courtyard buildings represent not only a modern reinterpretation of traditional wisdom but also an effective strategy for addressing future climate change. Deepening the understanding of their thermal regulation mechanisms, evaluation systems, and design methods will not only advance courtyards from passive cooling devices to comprehensive climate-adaptive and resilient strategies but also provide more sustainable and universally applicable solutions for buildings and cities facing multiple environmental challenges.