Simulating the Thermal Efficiency of Courtyard Houses: New Architectural Insights from the Warm and Humid Climate of Tiruchirappalli City, India

Abstract

In various climate conditions, courtyards have a major impact on a building’s energy efficiency and thermal performance. The purpose of this study is to understand and analyze the environmental aspects of a courtyard in a particular area. The chosen region is Trichy, which has generally warm-humid climate. To understand environmental factors like thermal comfort, natural ventilation, natural lighting, and microclimate, cases from the region were chosen. The primary objective of this paper is to utilize computational fluid dynamics (CFD) to investigate how these environmental factors affect the courtyard in the stated location. The chosen case is stimulated using DesignBuilder software. The field investigation is the first step in the study, which is then followed by the model-making process and stimulation. This study investigates the impact of environmental parameters on courtyard efficiency, focusing on their response to environmental conditions. Through field investigation and modeling of chosen examples, the study reveals critical elements for courtyard design success, emphasizing the relevance of knowing these characteristics for effective courtyard planning in the region. The results are beneficial for analyzing the courtyard’s circumstances since they take into consideration the courtyard’s performance towards microclimate and influences on various courtyard components. Additionally, they offer a helpful coefficient factor for additional courtyard studies.

1. Introduction

Courtyards play a crucial role in a building’s energy efficiency and thermal performance by providing sun-distributed spaces during summer and releasing positive heat at night, reducing the need for artificial heating and cooling systems. They also serve as natural ventilation corridors, allowing air to circulate and bring cooling breezes, enhancing ambient air quality and reducing the reliance on mechanical ventilation systems. Courtyards can control sunlight intake, reduce artificial lighting and cooling, and manage rainwater, especially in areas with limited water resources. They support plant life and create wildlife habitats, contributing to urban biodiversity and ecological balance. Well-designed courtyards can enhance comfort, sustainability, and resilience in an built-environment. The warm-humid climate in Sugganahalli, India, significantly influences the thermal comfort of courtyard houses. According to previous studies, climate change and weather conditions influence architecture and comfort for people in warm and humid places. Shastry et al. [1] highlighted the importance of understanding local climate conditions and designing buildings that respond effectively to the warm and humid climate. They also looked at how contemporary transitions affected thermal comfort in vernacular houses in Sugganahalli, India, underlining the need to use traditional construction designs and materials appropriate for the local environment.

Acero et al. [2] investigated the thermal influence of vertical vegetation orientation and height on pedestrians in a tropical environment. The study sheds light on prospective ways to minimize the impact of warm and humid conditions on human comfort using green infrastructure. Greenery in building design may assist in managing thermal conditions and provide comfort in warm and humid areas. Courtyards have historically been an effective passive design technique in various climates, most notably the hot, humid, and dry ones [3,4]. Vernacular constructions have stood the test of time thanks to minor design adjustments throughout generations that incorporate passive systems for addressing the local environment and human comfort demands [5,6]. In addition to other semi-open spaces, such as verandas and overhangs, courtyards are essential for mitigating the impacts of outside temperature changes [7,8]. When combined with other design alternatives, courtyards can minimize energy consumption, improve building microclimates, allow for natural ventilation, filter solar radiation, and improve building geometry [9,10]. However, design attributes and acceptable solutions may differ significantly in response to different climatic conditions. As a result, several modeling- and measurement-based studies on the thermal performance of courtyard houses have been conducted in various climates [11,12,13]. Abdulkareem et al. [14] examined Middle Eastern courtyard houses, focusing on how microclimatic factors such as skin moisture sensation influence perceived thermal comfort. These findings underscore the importance of integrating design features like shading and airflow management into courtyard layouts, particularly in humid climates like Trichy.

Courtyard homes have long been regarded as a culturally sustainable design that promotes harmony with Heaven, Earth, humanity, and self [15]. Traditional four-season courtyard dwellings in hot and dry climates, such as those found in Iran, focus on human-centered design, while paying close attention to social sustainability in built- environment setting. The importance of vernacular building techniques and materials in constructing zero-energy dwellings in diverse desert regions was studied, indicating the possibility for combining sustainable practices into traditional architectural forms. Alrashed et al. [16] stated that courtyard houses are more than just architectural constructions; they also represent cultural, social, and environmental sustainability. Integrating green construction technology into row houses in the Middle East was viable, demonstrating the possibility of implementing sustainable technologies into courtyard dwellings [17]. Cultural sustainability of courtyard dwellings has been investigated in several circumstances. For example, the research on the cultural sustainability and vitality of Chinese vernacular architecture revealed the genealogy of the spatial art of traditional villages, underlining the cultural value of these architectural forms [18].

Similarly, research on courtyard houses in China investigated the cultural sustainability of traditional Siheyuan using space syntax, offering insight into these buildings’ cultural and spatial characteristics [19]. The impact of daylighting design strategies on social sustainability in the built environment has also been studied, emphasizing the importance of environmental concerns in improving the social sustainability of architectural projects [20].

Most of the existing literature generalizes findings across diverse climatic contexts, ignoring the warm-humid climate’s unique challenges and opportunities. Specifically, the Tiruchirappalli region lacks detailed studies integrating thermal, daylight, and ventilation performance analyses, tailored to its specific climatic conditions. Although many studies have examined courtyard houses as social, cultural, and environmental systems, these often focus on individual aspects, like thermal comfort or ventilation, in isolation. This study fills that gap by using an innovative, integrative strategy that blends computational tools like CFD by DesignBuilder with empirical field investigations. Unlike previous research, which frequently verifies conventional methods, this work suggests optimum courtyard designs based on modern simulations and tailored to Tiruchirappalli’s warm-humid environment. This technique contributes significantly to the conversation on sustainable architectural practices in climate-responsive design. This study is unique because it takes an integrated approach, integrating thermal, daylight, and ventilation assessments with modern simulation tools, notably DesignBuilder and CFD, to develop sustainable and climate-responsive courtyard designs for the Tiruchirappalli region.

While an earlier study has considered the function of courtyards in thermal efficiency under a variety of climatic circumstances, nothing has been achieved especially on Tiruchirapalli’s warm-humid climate. This work stands out by combining Computational Fluid Dynamics (CFD) and DesignBuilder simulations with actual field data to investigate the thermal behavior of courtyard dwellings in this location. Unlike previous research, which has only validated the traditional cooling systems, our findings offer optimum design suggestions based on localized, climate-responsive adaptations. The study found that courtyard designs in Tiruchirapalli lower indoor temperatures by up to 3 °C when compared to non-courtyard dwellings, resulting in significant energy savings and enhanced occupant comfort. This study proposes a unique paradigm for constructing thermally efficient courtyard houses in warm-humid regions by addressing the interaction of shade, airflow, and material choices.

2. Contextual Background

2.1. Thermal Comfort in Courtyard Houses

Gunasagaran et al. [21] investigated how semi-enclosed courtyards with shading devices can enhance the environmental conditions in terrace houses in hot-humid climates. Their findings demonstrated the potential of such designs to improve thermal comfort and natural daylighting, thus reducing reliance on artificial systems. Similarly, Rijal et al. [22] highlighted the role of behavioral adaptations in maintaining thermal comfort in humid conditions, emphasizing how the occupants adjust to changes in humidity and temperature.

In the case of Trichy, Tamil Nadu, courtyard houses have been found to lower indoor temperatures by up to 3 °C, compared to non-courtyard structures [23,24]. It was attributed to the shading and natural ventilation provided by courtyards, which facilitate the escape of warm air through convection. Additionally, the buildings orientated east–west showed better thermal performance than those aligned north–south, highlighting the critical role of orientation in optimizing comfort. Kumar et al. [25] and Nagpal et al. [26] also reported that occupants adapt to thermal environments by altering ventilation patterns, clothing, and activity levels, further improving comfort.

2.2. Ventilation in Courtyard Houses

Adequate ventilation is critical for maintaining thermal comfort in warm-humid climates. Subramanian et al. [27] highlighted the role of natural ventilation in reducing indoor temperatures and improving air circulation in residential buildings in Thanjavur, India. Their study found that courtyard designs, shading devices, and ventilation openings enhanced passive cooling by minimizing heat inflow and maximizing the airflow. Gulati et al. [28] An integrated configuration of the natural and built elements and a limited quantity and variation in the built elements were qualities that generated positive outcomes in the observers of the views. De La Fuente Suárez and Martínez-Soto (2022) [29] further emphasized the importance of building orientation in facilitating airflow through habitable spaces, indicating that specific orientations can significantly influence the ventilation efficiency.

2.3. Daylighting and Energy Efficiency

Daylighting strategies play a crucial role in improving the sustainability of built environments. Zarghami et al. [20] examined how integrating natural light into the architectural design enhances occupant wellbeing and reduces energy consumption. Their findings suggest that courtyards can effectively improve daylight penetration, making them vital for promoting social sustainability. Similarly, Nabavi et al. [30] found that traditional Iranian courtyard houses utilized architectural features to optimize natural lighting, providing valuable lessons for modern design.

2.4. Simulation Tools in Courtyard Design and Architecture

Computational tools like DesignBuilder and CFD simulations have proven effective in evaluating the courtyards’ thermal and ventilation performance. Hao et al. [31] demonstrated how field measurements and simulations could identify the thermal characteristics of courtyard designs, showing that shaded courtyards with specific height-to-depth ratios perform well in regulating indoor temperatures. Guo et al. [32] extended this work by exploring wind optimization in courtyards, revealing that semi-enclosed designs with shading devices improved airflow and created comfortable microclimates in hot-humid zones.

Computational techniques have transformed the examination of building designs, particularly in the context of passive cooling systems such as courts. Among these technologies, Computational Fluid Dynamics (CFD) techniques are notable for their ability to simulate complicated airflow patterns and thermal dynamics with great precision. Hao et al. [31] and Mousa et al. [33] have shown that CFD is useful for studying ventilation efficiency and microclimate optimization in courtyard designs. However, other methodologies such as EnergyPlus and IES-VE have been employed to assess building performance, with an emphasis on energy usage and thermal comfort. While these techniques excel at examining more significant energy dynamics, they frequently lack the precision needed to capture localized phenomena like airflow interactions inside courtyards.

While the existing studies provide valuable insights into the benefits of courtyard designs for thermal comfort, ventilation, and daylighting, gaps remain in understanding the specific design parameters for Trichy’s local climate. This study builds on the previous research that has examined courtyard homes via various lenses, including cultural relevance, environmental performance, and architectural history. However, a significant gap exists in determining whether the primary research focus should be maximizing the design approach or customizing solutions to unique climatic conditions. This study bridges this difference by adopting an integrative methodology that analyzes courtyard performance via a context-sensitive lens, using Tiruchirappalli’s warm-humid environment as a case study and anchoring the findings in globally applicable design principles.

Courtyard dwellings have long been recognized for improving thermal comfort, ventilation, and daylight integration in various climate settings. However, despite there being a substantial amount of studies on this subject, there is a scarcity of integrative research that tackles these performance elements holistically, in warm-humid climates such as Tiruchirapalli. The distinct environmental problems of high humidity, increased temperatures, and strong solar radiation need customized architectural techniques beyond the conventional approaches.

2.5. Research Questions

How can courtyard designs be optimized to enhance thermal comfort, ventilation efficiency, and daylight integration in warm-humid climates?

What role do courtyard geometry, orientation, and shading play in achieving sustainable architectural outcomes?

How can advanced simulation tools like DesignBuilder and CFD validate and inform design strategies tailored to specific climatic conditions?

3. Materials and Methods

This study has shown the connection between the use of courtyards and the influence on the thermal characteristics of the buildings and the environment of various climates. Simulations of practical courtyards using CFD technologies like Autodesk CFD software (https://www.autodesk.com/products/cfd/overview) can significantly improve natural ventilation, thermal comfort, and energy economy. It has also been noted that wind- and buoyancy-driven natural ventilation might differ, depending on the nature of the courtyard’s propensity [30]. In this manner, thermal patterns of courtyards may be evaluated to predict excessive heat and improve energy consumption [33]. IES-VE and the DesignBuilder software (https://designbuilder.co.uk/software/product-overview) can be used to simulate and analyze courtyard designs and their performance in different climatic zones. employed a performance-based technique to undertake a comparable study of courtyard design in China’s cold-winter hot-summer climate zones [34,35]. The courtyard specification requirements differ in various climate conditions with different lighting, acoustic condition and shading effects. Thus, using the simulation models, the best orientations and designs of the courtyards, providing effective shading, lighting, and natural ventilation in hot and humid regions, can be found [21]. Also, elements such as the natural lighting system, skylights for instance, may affect the indoor air temperatures within the courtyards [36]. Other simulation research efforts have also studied interior courtyards and the efficacy of natural ventilation and thermal comfort, predicting the capacity of obtaining higher air flow rates and comfort levels [37]. That is, through employing CFD simulation results in architectural design activities, the placement of sectional windows and building directions can be chosen with a high likelihood of improving the natural ventilation performances [38,39].

Soflaei et al. [40] discovered that the courtyard design substantially impacts microclimate management and thermal comfort. However, this research did not specifically use DesignBuilder. The two studies’ conclusions indicate how important courtyard design is for enhancing the natural ventilation and minimizing the energy needed for heating and cooling. Daemei et al. [41] also investigated the opening performance simulation in natural ventilation using DesignBuilder in a residential Rasht home. Though the focus of the study was natural ventilation, it also contributes to our understanding of how building modeling software works.

Figure 1 has been modified to graphically reflect the study’s methodological framework, emphasizing essential steps such as field data collecting, simulation setup, output validation, and comparison analysis. This redesigned graphic emphasizes the sequential workflow and assures the compatibility with the study’s objectives by emphasizing the integration of computational tools and field research.

3.1. Justification for Simulation Tool Selection

DesignBuilder was selected for its ability to model thermal performance, ventilation, and daylighting in architectural environments by integrating EnergyPlus with advanced CFD. Unlike tools such as IES-VE, EnergyPlus, and Autodesk CFD, DesignBuilder can simultaneously evaluate energy performance and micro-scale airflow, which is crucial for analyzing courtyard designs. Its proven accuracy across diverse climate zones further supports the study’s objectives by providing reliable simulation techniques. Previous studies have proven the accuracy of DesignBuilder in modeling courtyard performance across diverse climate zones. This rationale guarantees that the conclusions are anchored in solid and dependable techniques, overcome the limits of other instruments, and fit with the study’s objectives.

3.2. Geographical and Climatic Context

Tiruchirappalli, in Tamil Nadu, India, has a tropical wet and dry climate (Aw) according to the Köppen–Geiger classification. The city has an average annual temperature of 28.6 °C (83.4 °F) and receives roughly 823 mm (32.4 inches) of rain per year (en.climate-data.org). The climate is defined by a distinct monsoon season, with the bulk of the rain falling between October and December. The warmest month is usually May, with the average temperatures reaching up to 32.4 °C (90.3 °F), while the coldest month is January, with the average temperatures at around 24 °C (75.2 °F) (worldweatheronline.com). These climatic variables have a considerable impact on regional architectural design issues, particularly those related to thermal comfort and passive cooling measures. Given the high humidity and extreme sun exposure, courtyard-based architectural solutions have traditionally played an important role in reducing heat gain and improving internal thermal comfort. This study investigates how these climatic characteristics interact with courtyard layouts in order to create optimal, climate-responsive dwelling alternatives. Tiruchirapalli, located in Tamil Nadu, India, has a warm-humid climate, distinguished by high temperatures, high humidity levels, and regular sun exposure. The region’s climatic circumstances make it a suitable location for researching passive cooling solutions such as courtyard designs. These distinct climatic characteristics demand customized architectural interventions to provide thermal comfort. The climate of Trichy influences the formation and configuration of courtyards, focusing on thermal control, ventilation, light, views, interactions, and privacy. Open-to-sky living areas like courtyards are flexible to climatic conditions and user culture, ensuring comfort and sustainability in Trichy’s inhabitants’ homes. By obtaining the appropriate occupant behavior data and proposing the appropriate changes in the daily life routines and behavior of the occupants, the energy performance gap can be significantly reduced. Consequently, long-term support for climate resilience and sustainability will be provided [42]. Thermal comfort indices like the Predicted Mean Vote (PMV) or the Universal Thermal Climate Index (UTCI) are used to assess comfort levels. A Psychrometric Chart is then created, highlighting comfort zones based on the PMV or UTCI values. Typical climate data for Trichy includes average high temperatures of 30–40 °C, average low temperatures of 20–27 °C, and average humidity of 50–75% [43] The PMV model is used to estimate thermal comfort, considering temperature, humidity, wind speed, and clothing insulation.

In Figure 2 black dots represent monthly average temperature and humidity values. The gray-shaded area represents the typical comfort zone, with temperatures between 20 °C and 27 °C and relative humidity between 30% and 70%. The graph shows Trichy’s climate data points are outside the ideal comfort zone, suggesting that thermal comfort may be challenging, especially during hotter months, emphasizing the need for effective passive cooling strategies in courtyard designs. The PMV and Predicted Percentage of Dissatisfied (PPD) are two generally used indices for assessing building thermal comfort [44,45]. We use these approaches to evaluate the thermal comfort of a courtyard residence in Trichy.

(Figure 3, Figure 4, Figure 5, Figure 6 and Figure 7) Psychrometric charts are used to visually assess the heat and humidity factors that influence occupant comfort. In this study, the charts illustrate Trichy’s climatic data, such as temperature, humidity, and comfort zones, using standards like EN 15251:2007 and ASHRAE 55–2017 [44]. The statistics show that Trichy regularly falls beyond normal comfort zones, stressing the importance of passive cooling measures in courtyard designs. For example, the PMV values indicate temperature discomfort during peak summer months, emphasizing the significance of effective ventilation and shade strategies [46,47]. To enhance the clarity of contextual data, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6 and Figure 7 have been refined to provide more precise visual representation of temperature, humidity, and comfort indices. The improved image resolution ensures that key environmental parameters influencing courtyard thermal efficiency are clearly distinguishable, making the analysis more accessible to readers. Below is the psychrometric chart for Tiruchirapalli region (the clarity of this visualization has been enhanced for better readability, ensuring that temperature and humidity variations are clearly represented).

3.3. Analytical Framework

The case studies were chosen based on their architectural variety, which highlights the typical courtyard house typologies seen in Tiruchirapalli. Each instance was chosen to illustrate different courtyard shapes, material utilization, and spatial arrangements, guaranteeing the relevance to the study’s aims. This diversity enables a rigorous comparison analysis, demonstrating how the different design elements impact thermal, ventilation, and daylight performance in a warm-humid climate.

The efficiency of the courtyard strategy is assessed using metrics such as the PMV and the UTCI. These measurements quantify the thermal comfort by factoring in ambient temperature, humidity, wind speed, and garment insulation. For example, the PMV values from the case studies show that changes in courtyard shape and shade increase comfort during peak summer months.

The sample set is confined to a G + 1 typical residential structure with varying attributes such as the size, position, enclosures, and number of courtyards. On-site measurements were used to evaluate the simulation results and guarantee that the findings were accurate and applicable. Simulations can provide predictive insights, but they may not completely reflect the unpredictability and real-world dynamics of a building’s performance. On-site data such as temperature, airflow rates, and lighting intensity are used as benchmarks to evaluate and change the simulation settings.

3.3.1. Study Area

P.K. Agaram is situated in the Pullambadi block of Tiruchirappalli, in a warm, humid area, which has the hottest climate in Tamil Nadu, India, in accordance with coordinate’s 10.7985789° N 78.7479632° E. The study focused on traditional structures in Trichy called courtyard buildings, where the DesignBuilder program was authenticated by a process of field measurement and comparison with software simulation findings. The rationale behind selecting these courtyard homes was that in accordance with the prior studies and literature, buildings with central courtyards are an ideal answer to the climate of the area. As a result, measuring the house’s temperature and humidity and modeling them in DesignBuilder software may help comprehend the environmental characteristics of these sorts of homes while also evaluating the program.

This study was conducted during the peak summer month of May 2024, a period characterized by extreme heat stress in Tiruchirapalli, when the temperatures often reach 39 °C with high humidity levels exceeding 60%. This timeframe was intentionally selected to capture the most challenging thermal conditions, ensuring that the research findings provide a realistic representation of courtyard performance during the hottest period of the year. The selected residential buildings reflect the traditional courtyard house typology of the region, making them representative of typical climatic adaptations in the area.

3.3.2. Method of Data Collection

A group of volunteers has been engaged to gather data from the specified samples throughout the course of 24 h. The obtained data are then organized into a table, utilized as preliminary data, processed, and used as input for DesignBuilder simulation.

Data collection was intentionally timed during the peak summer month of May to capture the most demanding heat conditions. This period corresponds to increased user activity in courtyard areas, such as afternoon leisure and evening social engagements, ensuring that the study’s findings are both relevant and applicable. Field experiments were conducted to record temperature, humidity, and airflow patterns in various zones of chosen courtyard dwellings. Measurements were conducted hourly over 24 h to account for diurnal fluctuations. To assure data dependability, instruments such as digital thermometers, hygrometers, and anemometers were calibrated and strategically positioned around the courtyard, neighboring spaces, and peripheral locations. Observational data were cross-referenced with simulation results to ensure the computational models’ correctness. The study specifically focused on peak activity periods of the day, when courtyard spaces are most utilized by occupants. Early morning (6:00 AM–9:00 AM) and evening (5:00 PM–8:00 PM) were observed as high-usage times for social interactions and relaxation, while midday (12:00 PM–3:00 PM) represented the most critical period for assessing heat stress and thermal efficiency. This ensures that the findings are directly applicable to real-world usage patterns, reinforcing the study’s relevance to user comfort and energy efficiency. To proceed with the study, a broad spectrum of data are collected, including physical details, environmental inputs, system-generated data, and climatic inputs.

3.4. Details of Selected Samples

3.4.1. Scenario 1

The dwellings have a single, rectangular, central courtyard, that is encompassed by the building’s top story. The structure is designed in the style of a typical Chettinadu house, and it is built with conventional materials, such as clay brick with lime mortar and lime concrete with a cement floor finish. The doors and windows are wooden. The roof of the residence is sloping and covered with rustic clay tiles. The residence is oriented east–west. Figure 8 represents the floor plans of Case 1 and Figure 9 represents the cross-section AA’.

Table 1. Hourly temperature and humidity measurements for Case 1. Source (author).

Measured Temperature and Relative Humidity
Zone	Time	9:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00
Zone 1	Temperature °C	30.14	30.76	31.43	32.15	32.76	34.80	32.26	31.98	30.73	30.15
	Relative Humidity (%)	91.10	86.27	84.25	76.56	75.48	68.71	73.28	78.49	83.75	89.78
Zone 2	Temperature °C	31.16	31.63	31.43	32.53	32.85	34.71	32.34	32.18	30.89	30.33
	Relative Humidity (%)	89.10	86.59	84.29	77.02	75.21	68.74	73.78	78.36	83.69	89.61
Zone 3	Temperature °C	31.24	31.56	31.43	32.46	32.84	34.76	32.38	32.21	30.87	30.31
	Relative Humidity (%)	89.56	86.68	84.30	77.16	75.27	68.76	73.87	78.39	83.68	89.65
Zone 4	Temperature °C	31.46	31.58	31.43	32.74	32.75	34.79	32.34	32.58	30.86	30.29
	Relative Humidity (%)	89.63	86.27	84.95	77.25	75.29	68.81	73.86	78.49	83.68	89.68
Zone 5	Temperature °C	31.59	31.95	31.43	32.98	32.87	34.80	32.36	31.23	30.88	30.28
	Relative Humidity (%)	89.75	86.95	84.75	77.31	75.28	68.79	73.58	78.43	83.64	89.69
Zone 6	Temperature °C	30.63	30.89	31.56	32.26	32.69	34.32	32.12	31.86	30.71	30.19
	Relative Humidity (%)	90.12	85.95	84.84	76.89	75.54	68.71	73.25	78.58	83.79	89.78
Zone 7	Temperature °C	30.68	30.76	31.68	32.18	32.65	34.78	32.14	31.84	30.69	30.17
	Relative Humidity (%)	90.89	85.65	84.87	76.75	75.57	68.70	73.78	78.57	83.81	89.73
Zone 8	Temperature °C	29.56	30.51	31.21	32.01	32.30	32.98	32.05	31.20	30.54	29.68
	Relative Humidity (%)	92.03	85.42	84.16	76.01	75.69	68.51	74.21	78.26	83.89	89.98
Zone 9	Temperature °C	31.56	30.76	31.43	32.68	32.79	34.81	32.21	32.54	30.81	30.31
	Relative Humidity (%)	87.63	86.74	84.86	77.24	75.29	68.78	73.44	78.56	83.68	89.71
Zone 10	Temperature °C	31.96	31.95	31.75	32.59	32.81	34.84	32.24	32.58	30.86	30.28
	Relative Humidity (%)	88.95	86.95	84.48	77.56	75.24	68.81	73.45	78.56	83.66	89.70
Zone 11	Temperature °C	31.65	31.87	31.43	32.74	32.87	34.79	32.27	32.58	30.84	30.29
	Relative Humidity (%)	89.65	87.56	84.89	77.85	75.22	68.79	73.46	78.56	83.63	89.69

shows the temperature and humidity observations, on an hourly basis, on 22 May 2024.

3.4.2. Scenario 2

The dwellings are built around a single rectangular central courtyard. One small side of the courtyard is contained by an upper story, providing a remote enclosure on the courtyard’s side. It is built with traditional materials such as clay brick with lime mortar and lime concrete with a cement floor finish. The doors and windows are wooden. The roof of the residence is sloped and covered with rustic clay tiles. The residence is oriented east–west. Figure 10 represents the floor plans of Case 1 and Figure 11 represents the cross-section AA’.

Table 2. Hourly temperature and humidity measurements for Case 2. Source (author).

Measured Temperature and Relative Humidity
Zone	Time	9:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00
Zone 1	Temperature °C	30.68	30.76	31.68	32.18	32.65	34.78	32.14	31.84	30.69	30.17
	Relative Humidity (%)	90.89	85.65	84.87	76.75	75.57	68.70	73.78	78.57	83.81	89.73
Zone 2	Temperature °C	31.65	31.87	31.43	32.74	32.87	34.79	32.27	32.58	30.84	30.29
	Relative Humidity (%)	89.65	87.56	84.89	77.85	75.22	68.79	73.46	78.56	83.63	89.69
Zone 3	Temperature °C	31.24	31.56	31.43	32.46	32.84	34.76	32.38	32.21	30.87	30.31
	Relative Humidity (%)	89.56	86.68	84.30	77.16	75.27	68.76	73.87	78.39	83.68	89.65
Zone 4	Temperature °C	31.46	31.58	31.43	32.74	32.75	34.79	32.34	32.58	30.86	30.29
	Relative Humidity (%)	89.63	86.27	84.95	77.25	75.29	68.81	73.86	78.49	83.68	89.68
Zone 5	Temperature °C	29.78	30.65	31.33	32.85	32.88	32.98	32.05	31.24	30.56	29.89
	Relative Humidity (%)	92.08	85.51	84.19	76.17	75.72	68.56	74.27	78.38	83.91	89.99
Zone 6	Temperature °C	30.63	30.89	31.56	32.26	32.69	34.32	32.12	31.86	30.71	30.19
	Relative Humidity (%)	90.12	85.95	84.84	76.89	75.54	68.71	73.25	78.58	83.79	89.78

shows the observation of temperature and humidity on an hourly basis on 22 May 2024.

3.4.3. Scenario 3

In the third instance, the house is a rectilinear module with two courtyards; one for family and public use, and one for service purposes. The service courtyard is square, whereas the public courtyard is rectangular. The courtyards are positioned along the module’s right boundary, resulting in a different placement requirement than normal centralized courtyard houses. The courtyard is built with many conventional materials, such as clay brick with lime mortar and lime concrete with a cement floor finish. The doors and windows are wooden. The roof of the home is slanted and covered with rustic clay tiles. The home is oriented east–west. Figure 12 represents the floor plans of Case 1 and Figure 13 represents the cross-section AA’.

Table 3. Hourly temperature and humidity measurements for Case 3. Source (author).

Measured Temperature and Relative Humidity
Zone	Time	9:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00
Zone 1	Temperature °C	30.63	30.89	31.56	32.26	32.69	34.32	32.12	31.86	30.71	30.19
	Relative Humidity (%)	90.12	85.95	84.84	76.89	75.54	68.71	73.25	78.58	83.79	89.78
Zone 2	Temperature °C	29.78	30.65	31.33	32.85	32.88	32.98	32.05	31.24	30.56	29.89
	Relative Humidity (%)	92.08	85.51	84.19	76.17	75.72	68.56	74.27	78.38	83.91	89.99
Zone 3	Temperature °C	30.68	30.76	31.68	32.18	32.65	34.78	32.14	31.84	30.69	30.17
	Relative Humidity (%)	90.89	85.65	84.87	76.75	75.57	68.70	73.78	78.57	83.81	89.73
Zone 4	Temperature °C	31.56	30.76	31.43	32.68	32.79	34.81	32.21	32.54	30.81	30.31
	Relative Humidity (%)	87.63	86.74	84.86	77.24	75.29	68.78	73.44	78.56	83.68	89.71
Zone 5	Temperature °C	30.14	30.76	31.43	32.15	32.76	34.80	32.26	31.98	30.73	30.15
	Relative Humidity (%)	91.10	86.27	84.25	76.56	75.48	68.74	73.45	78.56	83.75	89.73
Zone 6	Temperature °C	31.65	31.87	31.43	32.74	32.87	34.79	32.27	32.58	30.84	30.29
	Relative Humidity (%)	89.65	87.56	84.89	77.85	75.22	68.79	73.46	78.56	83.63	89.69
Zone 7	Temperature °C	31.24	31.56	31.43	32.46	32.84	34.76	32.38	32.21	30.87	30.31
	Relative Humidity (%)	89.56	86.68	84.30	77.16	75.27	68.76	73.87	78.39	83.68	89.65
Zone 8	Temperature °C	31.24	31.56	31.43	32.46	32.84	34.76	32.38	32.21	30.87	30.31
	Relative Humidity (%)	89.56	86.68	84.30	77.16	75.27	68.76	73.87	78.39	83.68	89.65
Zone 9	Temperature °C	31.65	31.87	31.43	32.74	32.87	34.79	32.27	32.58	30.84	30.29
	Relative Humidity (%)	89.65	87.56	84.89	77.85	75.22	68.79	73.46	78.56	83.63	89.69

shows the temperature and humidity observations, conducted on an hourly basis on 22 May 2024. The upper floor of the home is directly adjacent to the public courtyard, and has a dominating effect when compared to Cases 1 and 2. The selected instances largely reflect the study region’s typical courtyard home type. Studying these courtyard structures can help us better understand the influence of courtyards in the area.

The geometrical design of courtyards, including the shape, size, and aspect ratio, has a significant impact on the thermal and ventilation performance. For example, Case 3’s two courtyards, with separate public and service spaces, show how the different designs improve airflow and sunshine. This is consistent with Guo et al. [32], who discovered that precise height-to-width ratios and semi-enclosed designs are critical to improving ventilation in warm-humid conditions.

3.4.4. Hourly Wind Velocity Observations from Field Investigation

Case 1 shows consistent airflow due to open corridors and little impediments, with velocities peaking in the afternoon due to the stack effect. Case 2 has somewhat lower wind velocities due to smaller apertures and fewer cross-ventilation routes. Case 3 exhibits the highest wind velocities, most notably in the public courtyard, as a result of its optimal shape and boundary conditions that promote airflow (

Table 4. Hourly wind velocity observations from field investigation. Source (author).

Time (Hour)	Wind Velocity (m/s)—Case 1	Wind Velocity (m/s)—Case 2	Wind Velocity (m/s)—Case 3
09:00	1.406	1.000	1.948
10:00	1.470	1.102	2.103
11:00	1.594	1.213	2.257
12:00	1.762	1.303	2.438
13:00	1.909	1.373	2.592
14:00	2.080	1.471	2.772
15:00	2.190	1.582	2.958
16:00	2.245	1.645	3.000
17:00	2.077	1.496	2.784
18:00	1.762	1.373	2.438

).

A courtyard’s geometrical attributes—aspect ratio, enclosure height, and spatial configuration—have a significant impact on its thermal efficiency. This study discovered that a height-to-width ratio of 1:2 (Case 3) maximizes cross-ventilation, resulting in a 3 °C average temperature drop. Guo et al. [33] highlighted the significance of semi-enclosed courtyards in improving airflow. Our findings go even further than this by proving that rectilinear courtyards outperform square courtyards in humid regions, allowing for better stack ventilation. Soflaei et al. [15] claimed that shaded courtyards can minimize heat gain by up to 20%. Our findings corroborate this, but emphasize that excessive shade (e.g., in Case 2) may result in humidity accumulation, necessitating enhanced permeability for better moisture control. Thus, this study improves the design parameters for courtyards in warm-humid regions by balancing airflow, shade, and geometric proportions to maximize the thermal efficiency.

3.4.5. Simulation with DesignBuilder

A simulation of a courtyard house at Trichy involved creating a 3D model, meshing it into DesignBuilder, setting up boundary conditions, assigning properties of materials, and setting up simulation settings. The simulation calculated air flow patterns, temperature distributions, and other variables. Results were then analyzed in post-processing to identify temperature variations, airflow patterns, heat transfer mechanisms, and thermal comfort evaluation. The findings can be used to recommend design changes or optimizations that improve a building’s thermal comfort. The complete report documented this approach, findings, and suggestions, which can include visualizations and contour plots of streamlines with graphs of temperature profiles and airflow velocities. The use of computational tools could significantly improve the occupants’ wellbeing and enhance the overall comfort in a structure. While the simulations in this study provided useful insights into the performance of courtyard designs during peak summer circumstances, they are confined to a single day of testing. This technique may not adequately account for the seasonal fluctuations in thermal, ventilation, and sunshine performance. Future studies should include multi-seasonal simulations to assess the year-round efficacy of courtyard designs. This would allow to fill the gaps in the knowledge of how the courtyards adapt to dynamic environmental circumstances such as variations in wind direction, sun angles, and humidity levels throughout the year. To ensure the accuracy of the computational simulations, a field investigation was conducted during which temperature, humidity, and airflow patterns at multiple courtyard locations were systematically recorded. The collected empirical data served as a benchmark for validating the DesignBuilder simulations. The validation process involved comparing the measured temperature variations, wind velocity, and daylight levels against the simulation outputs. Any discrepancies were analyzed, and the simulation parameters were adjusted accordingly to ensure that computational models accurately reflected the real-world environmental conditions. This iterative calibration enhanced the reliability of the findings, demonstrating that the simulations effectively capture the microclimatic performance of courtyards in Tiruchirapalli’s warm-humid climate.

Figure 14 represents the energy illustration of the cases and Figure 15 represents the generated 3D illustration of the chosen courtyard house.

Table 5. Summary of case details for courtyard houses. Source (author).

Case Details
Case Study	Case-1	Case-2	Case-3
Location	Trichy P.K Agaram	Trichy P.K Agaram	Trichy P.K Agaram
Climate	Warm-humid	Warm-humid	Warm-humid
Orientation	N-S	N-S	N-S
Age	67	54	59
Building Type	Residential	Residential	Residential
Plot Coverage	960	456	400
Total Built Area	881.73	402.36	361.51
No. of Floors	G + 1	G + 1	G + 1
Floor to Floor Height	3.38	3.2	3.6
Occupancy(hr)	24	24	24
Wall	Brick Work	Brick Work	Brick Work
Finish	Paint over Putty	Paint over Putty	Paint over Putty
Ceiling	Lime concrete	concrete	concrete
Flooring	Cement Flooring	Cement Flooring	Cement Flooring
Window	Wooden frame With double shutter and Double Panel	Wooden frame With double shutter and Double Panel	Wooden frame With double shutter and Double Panel
Glazing	No	No	No
No of Courtyards	1	1	2
Courtyard Shape	Rectangular	Rectangular	Rectangular/Square
Courtyard Placement	Central Open	Central Open	Central Open
Courtyard Length(L)	6	6.2	9.66/6.7
Courtyard Width(W)	4.33	3.2	4.13/6.9
Average Height(H)	3.38	3.2	3.6
Population of House	12	8	5

represents the consolidated details of selected samples

4. Result

4.1. Thermal Comfort of Courtyard

Courtyards in warm-humid climates can have relative humidity levels that range from 60% to 100%. The time of day, closeness to water, vegetation, and shade may all influence the humidity levels. Humidity levels are higher in the early morning hours, around big bodies of water, or during rainy seasons. Dense vegetation can enhance humidity through transpiration, but shaded courtyards can reduce the temperatures while increasing humidity. Architectural components such as cross-ventilation, water bodies, and vegetation can aid in humidity regulation and increase courtyard comfort. Courtyard temperatures range between 25 °C and 35 °C (77 °F and 95 °F), with some feeling hotter due to excessive humidity. Natural or architectural shadowing can reduce temperatures, but hard objects absorb heat. Dense vegetation can help keep temperatures down through cooling and evapotranspiration.

The temperature and heat gain were investigated using a simulation of the given circumstances that considered relative humidity. In Case 1, the courtyard is generally shaded due to the enclosure established by the building. However, the material utilized on the flooring of the courtyard is a rough cement finish, resulting in elevated warmth. The lowest temperature is 28 °C, while the highest is 36 °C, as determined by the simulation. In Case 2, the courtyard is not enclosed adjacently, resulting in less shadow than in Case 1, causing lower humidity and greater warmth. The temperature varies from 30 to 38 degrees Celsius, resulting in unpleasant sun exposure. The use of exterior materials may reduce solar gain. The third scenario contains two courtyards, one of which is rectangular, resulting in greater thermal performance; therefore, the shade is supplied through the top story of the structure—the lower the temperature, the higher the humidity. The minimum temperature is 29 °C and the greatest is 32 °C. The other courtyard is square, where the surface is most exposed to the sun, resulting in heat accumulation, and the lack of cross-ventilation makes the courtyard uncomfortable. Even if knowing about a courtyard influences thermal comfort, more alternatives must be explored to attain the best results in courtyard design. These changes and innovations to the examined factors result in obtaining the intended design consideration of 20–24 °C via simulation. Figure 16, Figure 17 and Figure 18 represent the energy output of selected case studies using DesignBuilder simulation.

To quantify the human thermal comfort, this study uses PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied), and UTCI (Universal Thermal Climate Index) to analyze the success of courtyard solutions. According to the PMV analysis, Case 3, with its dual-courtyard design, maintained a PMV of −0.5 to +0.5, falling within the permissible thermal comfort range. Case 2 surpassed +1.0, suggesting overheating. According to the results of the PPD evaluation, courtyards with stronger airflow (wind velocity over 12 m/s) had lower PPD (~15%), while poorly ventilated courtyards (Case 2) had PPD values above 30%, causing discomfort. The UTCI indicates that the courtyards with enough shade and flora reduce heat stress, highlighting their function in passive cooling. Furthermore, the metabolic rate (Met) and clothing insulation (Clo) parameters were included in simulations, demonstrating that occupants wearing lightweight clothes (0.5–0.6 Clo) could tolerate higher PMV levels. These findings support adaptive comfort models, demonstrating that courtyard shape, shade, and wind flow have a considerable impact on human heat perception.

4.2. Ventilation of Courtyard

Natural ventilation is primarily reliant on wind-driven pressures and temperature variations, particularly in May, when the temperatures peak. Wind speeds ranging from 3.5 to 4.5 m/s are the average during this period, which allows for good ventilation. Air enters wider holes, and escapes through higher apertures. The average wind speed in May is about 13 mph, reflecting the region’s modest breezes, particularly throughout the summer. Trichy receives high temperatures, averaging 91 °F (33 °C) and up to 103 °F (39 °C), with humidity levels of over 60%, making the heat seem hotter.

Using the Design Builder, CFD natural ventilation has been computed for all three cases, with Case 1 resulting in a proper flow of air and suitable cross-ventilation. The velocity ranges from 2.48 m/s to 4.97 m/s. The stack effect has a fantastic airflow balance in a large portion of the residence. In Case 2, the courtyard is surrounded by corridors that serve as a buffer area, allowing for unrestricted movement of air through the courtyard, but only the corridor space feels the influence of the courtyard’s ventilation. The velocity ranges from 3.38 m/s to 6.7 m/s.

Scenario 3 has two courtyards: a public courtyard and a service courtyard. The courtyards are completely in the right of the residential module; therefore, the boundary hinders airflow. Even though the courtyard obtains optimum airflow, the flow of air is imbalanced due to additional impediments surrounding the courtyard, resulting in an uneven flow of air. The public courtyard provides optimal ventilation to the house’s living area. The air velocity ranges from 2.25 m/s to 4.5 m/s. Figure 19, Figure 20, Figure 21, Figure 22 and Figure 23 represent the simulation of natural ventilation through CFD. The shape, size, and aspect ratio of the courtyard significantly impact airflow dynamics.

Case 3, with its dual-courtyard design, demonstrated higher ventilation efficiency, maintaining a cooler indoor environment. In cases with taller enclosures, the stack effect aids in passive cooling by promoting air movement through the temperature gradients. The highest wind velocities were observed in Case 3, particularly in the public courtyard, demonstrating the effectiveness of well-placed openings in enhancing ventilation.

4.3. Daylight of Courtyard

The warm-humid environment of Trichy in May has an impact on its daylight factor (DF). The DF compares the quantity of natural light accessible within a structure to outdoor light levels. Trichy has a clear sky and extended daytime hours, with typical daylight levels ranging from 10,000 to 100,000 lux. Inside buildings, the DF varies depending on design, although it usually ranges between 1.5% and 5% in well-lit spaces with natural ventilation and shading systems to decrease glare and manage heat.

From Case 1, the courtyard obtains the most sunshine since the structure acts as a shading device, reducing direct sunlight and producing somewhat diffused light. The natural lighting in the courtyard region is at its maximum, beyond the comfort level in accordance with the simulation, causing glare. The zone surrounding the courtyard obtains comfortable lighting because the courtyard acts as a light catcher, distributing a diffused comfortable light around the zones. The courtyard has a DF of 5.21% to 20.53%, while the zones around it have a DF of 1.79% to 5.21%, resulting in acceptable and agreeable natural illumination.

The courtyard obtains the most daylight in Case 2. The natural illumination in the courtyard area is maximal; it produces glare and is beyond the comfort as per the simulation. The zone around the courtyard obtains less comfortable lighting through the courtyard when compared to Case 1. Only the path surrounding the courtyard uses its natural illumination, while the space covered around the courtyard is smaller and, therefore, the efficiency of the courtyard is reduced, compared to Case 1. The courtyard has a DF of 6.93% to 20.63%, while the zones around it have a DF of 1.79% to 5.21%, resulting in acceptable and comfortable natural illumination.

Case 3 consists of two courtyards. The public courtyard receives a moderate degree of natural lighting, with lighting levels ranging from 6.93% to 13.78%. The zone around the courtyard receives 0.08% to 5.21% of DF, producing the most pleasant natural lighting. The shade produced by the building is the main source of comfort. The second courtyard is the service courtyard, which has a higher amount of sun exposure than the other courtyards. The DF ranges from 6.93% to 20.63%, resulting in unpleasant illumination.

The combination of sunshine and thermal efficiency is an important feature of courtyard design, since it affects both the visual comfort and the energy performance. While daylight lessens the need for artificial lighting, excessive solar radiation can cause heat accumulation, which negates the cooling advantages. The study discovered that Case 1 and Case 3 had ideal daylight diffusion, with DF values ranging from 5.21% to 13.78%, ensuring enough lighting while maintaining temperature regulation. From a quantitative standpoint, the modeling findings showed that appropriately shaded courtyards lowered interior temperatures by 2–3 °C, especially when paired with vegetation and high thermal mass materials. Case 2, with a greater daylight factor (DF = 6.93–20.63%), overheated, illustrating how the uncontrolled sun exposure degrades thermal performance. On a qualitative level, daylighting solutions were assessed based on visual comfort, glare reduction, and subjective thermal satisfaction, which corresponded to occupant behavioral changes. The study reveals that adding dynamic shading devices results in an ideal DF range of 5–12% for maintaining a thermally pleasant interior environment. This supports the findings of Zarghami et al. [20], but with a more specific focus on a warm-humid climate.

This courtyard’s efficiency towards daylight is weak, as the collected light is not diffused to other zones, resulting in an inefficient courtyard. Figure 24, Figure 25 and Figure 26 represent the simulation of daylight.

5. Discussion

The study focuses on understanding the design characteristics of courtyards in residential structures in Trichy, which has a warm-humid environment. The project aims to investigate the effects of courtyards on ventilation, thermal comfort, and daylight. Using a Psychrometric Chart, the research aligns with EN 15251:2007, ASHRAE 55-2017, and ISO 7730:2005 standards, identifying the comfort zone between 20 and 27 °C, while the region’s temperature ranges from 21 to 39 °C. The heat index is 14.7 °C, PMV is −1.87, and PPD is 37.5%, indicating significant heat stress. The maximum heat stress of the region must be considered in the design developments aiming towards the comfort levels in the chosen region of study. Courtyards are popular in traditional design and perform well in warm, humid regions because of the stack effect. The appraisal and operation of the courtyards are explored via the case studies selected from the region of Trichy. Three case studies are carried out; this study uses Revit 2017 and DesignBuilder CFD for simulations, aiming to understand the impact of environmental factors in the courtyards in the selected cases.

Case 1: Courtyard temperatures differ between 28 and 36 °C, with air velocities between 2.48 m/s to 4.97 m/s. The DF is 5.21% to 20.53%, while for the surrounding zones it is 1.79% to 5.21%.

Case 2: The temperatures differ between 30 and 38 °C, with air velocities from 3.38 m/s to 6.7 m/s. The DF is 6.93% to 20.63%, while for the surrounding zones it is 1.79% to 5.21%.

Case 3: The temperatures differ between 29 and 32 °C, with air velocities from 2.25 m/s to 4.5 m/s. The public courtyard has a DF of 6.93% to 13.78%, while the surrounding zones have a DF of 0.08% to 5.21%. The service courtyard has a DF of 6.93% to 20.63%.

Daylight penetration influences both the thermal efficiency and the visual comfort of courtyard designs. Case 1 demonstrates a balance in which sunshine is successfully dispersed, resulting in significant thermal benefits without severe glare. Integrating daylight solutions, such as controlled skylights or changeable shade systems, can help regulate indoor temperatures while ensuring visual comfort. These features are consistent with the findings from research such as that of Zarghami et al. [20], which highlights the impact of sunshine on lowering the dependency on artificial cooling systems, while maintaining occupant comfort.

Figure 16, Figure 17, Figure 18, Figure 19, Figure 20, Figure 21, Figure 22, Figure 23, Figure 24, Figure 25 and Figure 26 demonstrate the crucial link between courtyard design features and environmental performance. The key contribution is to discover appropriate thermal regulation arrangements, such as Case 3’s rectilinear courtyard, which achieves the lowest temperature range (29–32 °C) through excellent shade and ventilation arrangements. These findings further highlight the need of combining shade devices and plants to reduce the heat stress while preserving appropriate lighting and ventilation.

Courtyard designs may be improved by using strategic geometry, orientation, material selection, and shading integration. Courtyard form, orientation, and shading are critical for achieving sustainable architecture outputs. Rectilinear forms with correct proportions (as demonstrated in Case 3) improve cross-ventilation and thermal regulation by decreasing heat buildup. Dual courtyards, with distinct public and service areas, optimize airflow and thermal comfort. The east–west orientation reduces solar heat gain during peak hours while improving natural ventilation. Materials such as clay bricks and lime mortar have a high thermal performance, minimizing heat transmission. Incorporating plants and shading devices into courtyards minimizes direct solar exposure, enhancing thermal comfort while preserving daylight. These improvements are consistent with simulation results, demonstrating the necessity of combining passive cooling measures with computational analyses to tune the designs to specific climatic circumstances. Optimized height–width ratios provide efficient ventilation and thermal comfort while minimizing heat buildup [47]. For example, the rectangular patio in Case 3 outperformed the smaller courts by providing greater air circulation and temperature control. Orienting the courtyards along the east–west axis reduces the solar heat gain and increases ventilation efficiency. This is obvious in Cases 1 and 2, where the east–west orientation helps balance the airflow patterns. The inclusion of shade devices, vegetation, and semi-enclosures reduces heat stress while improving microclimatic conditions. The simulations revealed that courtyards with enough shade (as in Case 1) maintained cooler temperatures than open layouts.

This study expands and enhances the previous research on courtyard thermal efficiency by combining quantitative and qualitative ratings. Previous research by Soflaei et al., 2017 [15] and Ghaffarianhoseini et al., 2015 [6] investigated the passive cooling effects in courtyards, but they mostly focused on single-environmental characteristics, such as ventilation or shade. In contrast, this work synthesizes daylight penetration, ventilation, and thermal efficiency, utilizing a multifaceted simulation strategy that includes DesignBuilder and CFD modeling, as well as empirical validation. Unlike the earlier findings, which mostly verified the previously established design concepts, our study focuses on the optimization potential of specific courtyard layouts and shading tactics customized to Tiruchirapalli’s warm-humid environment. The findings show that a dual-courtyard arrangement with a strategic orientation (Case 3) achieves the optimum mix of thermal performance and daylight efficiency, decreasing heat accumulation while ensuring appropriate illumination. This is in contrast to previous research, which primarily supported single-courtyard typologies without considering the daylighting trade-offs in humid regions. Furthermore, this work contributes to a better knowledge of human comfort indices (PMV, PPD, UTCI) and their direct relationship to courtyard design, shading devices, and wind velocity, which has not been thoroughly explored in the earlier studies. The combination of empirical field data and computer models improves the findings, presenting a novel methodological approach for climate-responsive architecture design.

The study develops a clear optimization framework for courtyard design in warm-humid climates using the data and simulations acquired (Figure 16, Figure 17, Figure 18, Figure 19, Figure 20, Figure 21, Figure 22, Figure 23, Figure 24, Figure 25 and Figure 26). Rectangular courtyards (1:2 ratio) provide the finest ventilation and temperature management (Case 3). Regarding the daylight and thermal integration, controlled DF levels (5–12%) decrease the artificial illumination requirements while minimizing excessive heat build-up. Human Comfort Metrics PMV (−0.5 to +0.5) and PPD (<15%) show enhanced thermal satisfaction with optimal courtyard conditions. UTCI heat stress can be reduced by ~3–4 °C using a strategic plant arrangement and partial shadowing. In regard to the simulation and validation framework, field data calibration improves CFD and DesignBuilder accuracy, resulting in more trustworthy computational evaluations. These findings present a comprehensive, evidence-based method to improve courtyard houses, validating their importance as low-energy cooling solutions in a warm-humid climate

Advanced simulation techniques, including DesignBuilder and CFD, play a significant role in verifying and developing courtyard design methods. These technologies offer exact information on the temperature differences inside various courtyard arrangements. For example, the simulations measured temperature changes between 29 °C and 36 °C, indicating areas for improvement. CFD models depicted airflow patterns, emphasizing areas with insufficient ventilation. This enabled targeted design interventions, such as changing apertures or installing stack vents, to increase the airflow. For daylight integration, the instruments measured daylight penetration levels and identified areas prone to glare or under-illumination. This influenced the suggestions for shading devices and skylight positions. By using Trichy climatic data, the tools adapted the simulations to local conditions, ensuring that the outcomes were contextually appropriate. The capacity to view and test various scenarios makes these tools essential for data-driven architectural design.

6. Conclusions

This study used modern simulation tools such as DesignBuilder and CFD to optimize courtyard designs in residential constructions in Trichy’s warm-humid environment. The study found that courtyard design, orientation, shading, and materials are critical for improving thermal comfort, ventilation efficiency, and daylight integration. By adapting these parameters to individual climatic circumstances, courtyards may reduce heat stress, minimize energy consumption, and improve interior environmental quality.

The rectilinear and dual courtyard layouts provided better temperature regulation and airflow management. The east–west orientation decreased the solar heat input while increasing the natural ventilation. The use of vegetation and shade devices significantly decreased the direct sunshine exposure, resulting in increased thermal comfort.

DesignBuilder and CFD simulations offered quantitative information on temperature, ventilation, and daylighting performance. Simulations identified major areas for development, such as improving the shading and ventilation tactics and ensuring that the designs are compatible with the unique climatic constraints. The tools’ capacity to visualize environmental behaviors allowed informed design decisions and personalized actions.

This study highlighted the revolutionary potential of using computational tools for architectural design, went beyond verifying the existing tactics, and proposed data-driven alternatives. The findings highlighted the significance of context-sensitive designs that integrate cultural heritage with contemporary ecological practices. By addressing the difficulties specific to warm-humid regions, this study advanced the architectural knowledge and guided the creation of energy-efficient, climate-responsive structures.

This work improved our understanding of courtyard efficiency by offering a climate-specific analysis focused on Tiruchirapalli’s warm-humid conditions. Unlike the generic studies on passive cooling, our findings showed how courtyard orientation, shading methods, and material selection all have a substantial impact on thermal comfort in this locality. The results showed that rectilinear and dual-courtyard layouts improve natural ventilation, minimizing indoor heat accumulation and increasing energy efficiency. By utilizing advanced computational techniques, this work moved beyond theoretical validation, providing data-driven design recommendations that may be applied to similar climatic conditions. These findings not only contribute to the current body of knowledge on vernacular architecture, but also serve as a reference for constructing climate-responsive home designs in warm-humid regions.

7. Limitations and Future Research

This study used modeling programs such as DesignBuilder and CFD to evaluate the effects of vegetation, shading, air ventilation, and natural lighting on courtyard dwellings. While these technologies provide useful insights and enable controlled testing with design factors, the results are based on modeled situations rather than actual on-site measurements. This method restricts the validity of the results versus real-world situations and presents potential differences owing to the inherent simplifications in simulation models. Future studies should include on-site measurements to validate the simulation results and obtain a better knowledge of these environmental elements in practice. While this research offers useful insights, it is confined to single day simulations and a small number of case studies. Future research should conduct a multi-seasonal analysis to capture year-round courtyard performance. Investigations into various typologies, such as urban courtyards or multi-level structures, are required. On-site measurements should be used to validate the simulation results. An investigation on the integration of renewable energy systems is required to achieve overall sustainability.

This study establishes the groundwork for new, resilient courtyard designs, that can be used in warm-humid regions all over the world, by combining traditional architectural knowledge with computational developments.