Parametric Visualization, Climate Adaptability Evaluation, and Optimization of Strategies for the Subtropical Hakka Enclosed House: The Guangludi Case in Meizhou

Abstract

Hakka traditional vernacular dwellings embody regionally specific climatic adaptation strategies. This study takes the Meizhou Guangludi enclosed house as a case study to evaluate its climate adaptability with longevity and passive survivability factors of the Hakka three-hall enclosed house under subtropical climatic conditions. A mixed research method is employed, integrating visualized parametric modeling analysis and on-site measurement comparisons to quantify wind, temperature, solar radiation/illuminance, and humidity, along with human comfort zone limits and building environment. The results reveal that nature erosion in the Guangludi enclosed house is the most pronounced during winter and spring, particularly on exterior walls below 2.8 m. Key issues include bulging, spalling, molding, and fractured purlins caused by wind-driven rain, exacerbated by low wind speeds and limited solar exposure, especially at test spots like the E8–E10 and N1–N16 southeast and southern walls below 1.5 m. Fungal growth and plant intrusion are severe where surrounding trees and fengshui forests restrict wind flow and lighting. In terms of passive survivability, the Guangludi enclosed house has strong thermal insulation and buffering, aided by the Huatai mound; however, humidity and day illuminance deficiencies persist in the interstitial spaces between lateral rooms and the central hall. To address these issues, this study proposes strategies such as adding ventilation shafts and flexible partitions, optimizing patio dimensions and window-to-wall ratios, retaining the spatial layout and Fengshui pond to enhance wind airflow, and reinforcing the identified easily eroded spots with waterproofing, antimicrobial coatings, and extended eaves. Through parametric simulation and empirical validation, this study presents a climate-responsive retrofit framework that supports the sustainability and conservation of the subtropical Hakka enclosed house.

1. Introduction

Traditional vernacular architecture embodies human wisdom in adapting to climatic conditions [1]. Through spatial configuration and material innovations, these structures enhance longevity while improving living comfort, demonstrating remarkable climate responsiveness [2,3]. The utilization of indigenous materials and construction techniques enables buildings to achieve exceptional sustainability through localized climate adaptation [4]. Their microclimate regulation capabilities are particularly noteworthy, encompassing thermal insulation, solar shading, natural ventilation, and humidity control [5,6,7]. For instance, in sub-Saharan west Africa, low-tech traditional dwellings exhibit outstanding climate adaptability, sustainability, and bioclimatic characteristics, gaining popularity for their superior thermal comfort performance. Similarly, traditional buildings in northeastern Portugal employ bioclimatic energy-saving strategies to enhance thermal comfort and living quality [8]. In the humid subtropical region of Lingnan, the spatial organization and architectural scale of the Hakka enclosed house in Meizhou reflect climate-responsive design principles [9]. Key features such as a central patio, fenestration design, building orientation, and material selection contribute to effective ventilation and thermal insulation [10], making these structures valuable for adaptive preservation and cultural heritage studies [11].

However, evolving lifestyles and global warming are altering housing preferences, and with an increasing emphasis on aesthetic standards and climatic performance, many Meizhou residents are abandoning traditional enclosed houses in favor of modern alternatives, potentially leading to the cultural homogenization of Hakka settlements [12]. Consequently, optimizing climate-adaptive strategies has become a priority for architects [13] and a central concern for residents [14,15]. Scholars believe that enhancing building climate adaptability not only improves living conditions in subtropical regions [16] but also reduces energy waste, increases comfort, extends building longevity, and preserves Hakka cultural heritage [12]. Integrating climate adaptability standards into architectural retrofits supported by climate modeling and energy simulations can guide dwelling design, residential policy, and performance assessments [17]. Thus, it is necessity to explore the climate-responsive advantages of Hakka dwellings for their preservation and adaptive reuse.

Key factors influencing architectural adaptability include robustness, redundancy, reflectivity, response speed, longevity, and passive survivability [18]. Among these, longevity combined with structural resilience and context-specific flexibility emerges as a core strategy for enhancing sustainability [19]. Passive survivability, defined as a building’s ability to maintain safe and comfortable conditions through passive design under climatic stresses, reduces energy dependence while improving performance [20,21,22]. Wind, rain, and solar radiation critically affect building longevity through mechanisms like wind erosion, rain-driven moisture infiltration, and thermal loading, while wind speed, humidity, solar irradiation/illuminance, and temperature jointly determine key human comfort metrics for evaluating passive survivability [23,24].

Globally, architectural climate adaptability remains a critical research focus [17,25]. Recent advancements include phase-change materials (PCMs) for thermal regulation in building envelopes [26], microencapsulated PCM wall systems, self-cleaning exterior coatings, transparent insulating glazing, hybrid evaporative cooling with photovoltaic roofs, VOC-reducing materials for indoor air quality, and building-integrated photovoltaics (BIPVs) [27]. Additional strategies encompass shading designs, ventilation systems, rainwater management, humidity control, and thermally responsive materials, all integral to climate-resilient vernacular architecture [28]. Although modern technologies can enhance traditional housing durability, passive survivability, and comfort, vernacular solutions like Hakka enclosed houses retain irreplaceable advantages in ecological cycles, construction costs, maintenance, and longevity [29,30,31].

To map current research on Hakka dwellings, our team employed VOS viewer to generate a knowledge graph (Figure 1). As of August 2024, studies have primarily focused on Hakka culture, architectural typology, settlement morphology, cultural origins, sociocultural aspects, tourism resources, symbolic features, and feng shui principles, with emerging work on arc-shaped dwellings. Recent investigations have applied computational modeling and field measurements to analyze thermal comfort ratios, wind patterns, humidity, daylighting, and sensitivity differences in the three-hall enclosed house and Chaoshan vernacular architecture [32]. Other studies have evaluated indoor/outdoor thermal environments, natural ventilation, and lighting performance through field surveys [33,34,35].

Despite these contributions, our bibliometric analysis reveals limited research on the climatic adaptability of Hakka dwellings. While foundational studies provide empirical support for Meizhou’s geo-climatic adaptations [32,36,37,38,39], critical gaps persist in the methodology and scope. The existing work predominantly relies on sensitivity analyses, environmental monitoring, and large-scale surveys [27], lacking integrative approaches that combine simulation, empirical validation, and comparative assessments. Crucially, few studies examine longevity and passive survivability to formulate targeted preservation strategies for the subtropical Hakka enclosed house.

From the perspective of longevity and passive survivability, this study addresses the following research question: Do Meizhou Hakka dwellings exhibit superior architectural adaptability? We aim to comprehensively evaluate the climate responsiveness of Hakka enclosed houses, with Guangludi Weilongwu as a case study. By integrating computational simulations, empirical measurements, and human comfort criteria, we will assess environmental longevity; establish baseline models under standard and historical climate conditions; conduct field measurements of thermal, wind, hygric, and luminous parameters; validate model accuracy through data comparison; and identify structural vulnerabilities to natural stressors. This study also evaluate passive survivability by gauging climate adaptability across seasons using metrics like thermal comfort percentage, ventilation efficacy, enthalpy–humidity ratios, and illuminance compliance with comfort standards.

This study will generate scientifically validated parameters to enhance Hakka enclosed houses’ sustainability and resilience. The outcomes will advance theoretical frameworks on longevity and passive survivability while providing actionable data and strategy for heritage management and contemporary Hakka-inspired designs.

2. Literature Review

2.1. Hakka Enclosed Dwelling in the Meizhou Climate

According to data from the government and the CBE climate tool, the geographical coordinates of Meizhou City are 23°23′–24°56′ N and 115°18′–116°56′ E. It is located in the northeastern part of Guangdong Province (Figure 2). The region experiences relatively high temperatures, with notable hot weather; the rainy season is long, with less rainfall at the beginning and more toward the end; and typhoons tend to occur later in the season, causing significant damage. Overall, the weather throughout the year is relatively stable, characteristic of a typical climatic year. From the years 2003 to 2024, the average annual temperature was 21.9 °C, ranging between 21.3 °C and 23.0 °C, with an overall average of 22.1 °C, a maximum temperature of 35 °C, a minimum temperature of 5.5 °C, and solar radiation measured at 1879.32 kWh/m², which is related to lighting and thermal comfort [38].

Meizhou is known as the “World Hakka Capital” and is the main settlement area for the Hakka people, possessing a rich Hakka residential culture [32,36]. Meizhou is famous for Hakka enclosed houses, which are characterized predominantly by semicircular shapes rich in Lingnan features [35]. There is a diverse range of residential types in Meizhou, including gate houses, lock houses, cross-hall houses, and enclosed houses [37], while enclosed houses occupy a high ratio in Meizhou residential houses [39]. The Hakka enclosed houses in Meizhou consist of square enclosed house and dragon-enclosed house types. The total number of dragon-enclosed houses with different hall types amounts to at least 248, while the three-hall dragon enclosed houses number 175, making up over 70% of the total. Thus, the three-hall dragon enclosed house is the most typical style of Hakka house in Meizhou [28,38,39].

A typical three-hall dragon enclosed house is the Guangludi enclosed house located in Dapu county, Meizhou city, Guangdong province, which exemplifies a typical three-hall dragon house with and four lateral rooms (Figure 3). This study references data on traditional Hakka enclosed houses in Meizhou [28,36], conducts field investigations and measurements of the GEH since end of the year 2021 until 2025, and incorporates information from the Meizhou Hakka Museum to compile data for this study.

The GEH was initially constructed in the 31st year of the Guangxu reign (corresponding to 1905–1908), according to the document named State Council of China in 2019. The total building square is 4180 m². It contains 18 halls and 13 patios, with a total of 99 rooms (Figure 3). The entire structure faces northwest and is backed by the southeast. It features a timber and earth structure, with a mudstone patio floor that adheres to the traditional Chinese architectural design principle of “four waters converging to the hall”. The interior is characterized by raised beams, dougong brackets, and decorative carvings or sculptures on the doors and windows [36,39].

The GEH is located in a stretch of farm land as a typical three-hall dragon enclosed house, generally consisting of three halls (spots N1, N2, and N3), as shown in Figure 3 and

Table 1. Spots of the GEH.

Identification Spots	Spots
Inner house spots (off ground 1.2 m, middle of the patio test the inner house wall’s natural erosion by wind, heat, and humidity)	N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16
Exterior house spots (off ground 1.2 m, off wall 0.1–0.3 m, aim to test the wall’s natural erosion by wind, heat, and humidity)	E1, E2, E3, E4, E5, E6, E7, E8, E9, E10, E11, E12, E13
Roof spots (aim to test the thermal and illuminance indicators)	H1 (Lower hall), H2 (Middle hall), H3 (Upper hall), H4 (watch tower enclosed rooms), lateral rooms (H6, H8, H9, and H12),

, patios and rooms around patios (spots N2, N3, N5, N6, N7, N8, N9, N10, N11, and N12), and the enclosed rooms (spots H6–H7 and H10–H4–H11). The Hakka three-hall dragon enclosed house in Meizhou is typically surrounded by Fengshui forest outside of H4 at the rear and Heping ground outside of N1 at the front.

The local people employs “Wakeng” as the unit, referring to the width between the midlines of two adjacent roof tiles in the Meizhou enclosed dwelling based on physical observation and introduction sources from the local peole and Meizhou museums. Due to variations in tile sizes, enclosed houses in Meizhou exhibit differences in scale. The number of “Wakeng” is typically odd, generally ranging from 17 to 21. In this study, all measurements have been converted to the International System of Units (meters). The three-hall layout includes an Upper hall, Middle hall, and Lower hall. The widths of the halls are as follows: the Middle hall is the widest, with a width of 5.1–5.2 m; the Lower hall ranges from 4.5 m to 4.8 m; and the Upper hall spans from 4.8 m to 5.1 m. The width of the patio of the Main hall ranges from 5.1 to 5.6 m, while the width of the side (N5, N6, N7, N8, N9, N10, N11, N12) patios illustrated in Figure 2 and listed in Table 1 have a size of 4.8 m to 5.1 m. The width of the rooms is standardized, with a range of 2.0 m to 3.3 m. The depth of the halls, rooms, and corridors varies from 3.8 m to 5.1 m, while the dimensions of the main hall room are approximately 2.0 m to 3.3 m. The depth of the courtyard measures between 2.3 m and 3.7 m.

2.2. Terms of Subtropic Climate and Architectural Adaptability

Climate significantly influences the internal maintenance of comfortable temperature, and humidity, illumination and radiation together impact microbial communities within buildings [6,23,41,42]. Currently, there is no standardized definition for climate adaptability. The objectives of climate adaptability can vary. A common definition in the field of architecture refers to the ability of buildings to adjust to climatic indicators such as solar radiation, wind, and humidity in the natural environment [23,43], including robustness, redundancy, reflectivity, responsiveness or rapidity, longevity, and passive survivability [18]. This study investigates the physical adaptability of the GEH in a subtropical climate, focusing on longevity and passive survivability. Longevity contributes to building longevity and resilience. When combined with flexible use and structural strength under specific conditions, it becomes a key strategy for enhancing resilience and promoting sustainability [19]. Architectural forms adapt to climatic conditions, while natural indicators such as temperature, humidity, light, and precipitation significantly impact the physical performance of the buildings themselves, leading to longevity issues [24,44,45]. Climate indicators such as intense solar exposure, weathering, and rain infiltration, including soaking and wind-driven rain, directly contribute to the erosion of building structures. Under climatic influences, the combined effects of humidity, temperature, wind, and solar illuminance foster microbial colonization within buildings, resulting in the growth of mold and vegetation, which in turn causes cracks and structural damage to walls and floors [23,41,42,43]. Japanese scholars have found that when indoor temperatures are maintained at 25 °C and relative humidity remains below 75% RH, mold growth is significantly inhibited, and surface coatings are less prone to fungal degradation. Adequate ventilation facilitates thermal exchange within building interiors, reduces humidity levels, and effectively curbs mold proliferation [46]. In the subtropical Lingnan region in China, the application and regular maintenance of waterproof lime-sand mortar or calcium carbonate-based coatings can effectively reduce wind-driven rain impacts and minimize sulfate accumulation on walls, thereby preventing gypsum-induced expansion and the deterioration of rammed earth walls [47,48]. Such protective measures also help lower indoor humidity and reduce the effects of biological weathering [49]. Regular removal of moss and vegetation from wall surfaces is another effective means of preserving rammed earth structures [50]. However, in low-humidity or arid environments, building materials may undergo expansion, softening, embrittlement, bulging, or cracking. The building’s spatial layout, window and door dimensions, construction materials, and orientation exert significant influences on thermal conditions, humidity control, ventilation, and natural lighting [23,43]. Therefore, the use of ventilated and waterproof surface materials, external physical shading, regular biological cleaning, as well as optimized spatial design and orientation constitute effective strategies to enhance the longevity of rammed earth buildings in subtropical climates.

Passive survivability refers to the building’s ability to maintain safety and comfort under climate change using passive design strategies that reduce energy consumption and enhance performance [20,21,22]. The passive survivability factor in the context of building physics is grounded in human comfort [51]. The adaptability of buildings to subtropical climates should be reflected in the reduction of adverse impacts from high wind, high humidity, large diurnal temperature variations, and solar radiation on human thermal comfort, while creating livable environments through optimized design [41,42]. This form of adaptability embodies the interactive relationship between buildings and climate change, representing a dynamic process of mutual adjustment. Simultaneously, creating a habitable indoor environment through optimized design is essential [39,44]. Improving ventilation performance can enhance heat exchange and reduce indoor temperature [47,50], thereby improving the overall perceived comfort of occupants [51]. The human comfort zone serves as a key metric for assessing the passive survivability of residential dwellings. Human comfort is a holistic perception influenced by a combination of indicators, including humidity, individual physiological state, temperature, wind speed, and solar exposure [50]. When temperature, light intensity, and radiation exceed certain thresholds, the human body may experience dizziness, accelerated respiration, and an elevated heart rate [52]. In terms of temperature, the optimal indoor temperature range for temperate or cold climates lies between 22 °C and 24 °C. Both excessively high and low temperatures can impair work and learning efficiency, with low temperatures increasing the risk of cardiovascular and respiratory diseases, and high temperatures exacerbating respiratory ailments. During periods of pronounced thermal discomfort, the efficiency of evaporative cooling through perspiration is significantly reduced, leading to a marked increase in heat-related discomfort. Furthermore, the dew point temperature during high-humidity periods in summer typically ranges between 24 °C and 26 °C, approaching the temperature of human skin, which further impedes the dissipation of body heat [50,51,52].

Wind and ventilation serve to dilute pathogens and pollutants, thereby mitigating health issues. However, exceeding the comfortable ranges of temperature, lighting, radiation, and humidity can also trigger psychological problems [52,53,54]. Regarding these parameters, in China, the comfortable wind speed is below 2 m/s in winter and below 5 m/s in summer [29]. A wind speed range of 0.5–3 m/s and a relative humidity of 30–60% RH are considered comfortable for humans, [29,53,55,56,57]. Boduch M. and Fincher W. have demonstrated that humans do not perceive changes in humidity within the range of 25–60% RH, which defines the humidity comfort range [50]. A relative humidity range of 40% to 60% is conducive to health, enhances work performance, and reduces the risk of infection. For instance, at 20 °C, a relative humidity of 50% RH feels warmer than 40% RH [48]. In hot and humid regions, the humidity comfort range lies between 0.008 kgw/kga and 0.014 kgw/kga [58]. From previous studies, the human comfort zone is typically defined as 18–25 °C in summer and 20–27 °C in winter [59].

Internationally, there are varying standards for the comfort zone in buildings. Comfort zones are typically delineated by specified air temperature ranges; for example, the Chartered Institution of Building Services Engineers (CIBSE) recommends a temperature range of 21–23 °C for office buildings, while the Occupational Safety and Health Administration (OSHA) suggests a range of 20–24.2 °C, and ENISO 7730 imposes a temperature range of 20–26 °C [52]. Along with this, ASHRAE 55 sets the range at 21.5 m/s–24 °C [55]. In China, the thermal comfort range for occupants in residential buildings is maintained at 18–24 °C. Regarding wind speed, air circulation should be increased by 1.2–1.5 m/s in still areas. According to Clause 7.2.9 of Standard for assessment of green building (Revised) (Draft for comment) (GB/T 50378-201) in 2018 and Assessment Standard for Green Building Design in Guangdong Province (Revision) in 2024 (index number 006939799/2024-00505) adviced that the wind speed at 1.5 m above ground level around buildings should not exceed 5 m/s, and in outdoor rest areas and children’s play areas, it should be below 2 m/s [60,61]. The comfortable wind speed range generally falls between 0.8 m/s and 3.0 m/s. When the temperature is between 6 °C and 20 °C, the wind speed should be below 1 m/s [62]. Given that winter temperatures in Meizhou mainly range between 5 °C and 17 °C, the comfortable wind speed in winter should be below 1 m/s, and between 0.8 m/s and 3.0 m/s in summer. Clause 5.2 of the Standard for residential building performance assessment (GB/T 50362-2023) stipulates that high-quality residential buildings scoring 9–12 should have over 60% of their area illuminated at above 300 lux for at least 8 h per day [60,61,62]. The lighting range is related to the duration of exposure, 1700–2500 lux enhances human attention and well-being compared to levels below 1100 lux, while 100 lux can induce drowsiness [63]. Only illumination above 2000 lux allows for the observation of fine fabrics [50], and levels exceeding 100,000 lux cause visual discomfort. Lighting below 875 lux defines the human visual comfortable zone [64]. Therefore, for residential buildings, the lighting in reading areas within bedrooms during the day should be between 300 lux and 875 lux, while in other spaces, it should remain below 100,000 lux for optimal comfort.

Hakka enclosed dwellings in Meizhou are situated in a subtropical climate characterized by high temperatures and humidity [37]. From the perspective of creating a comfortable and healthy living environment, the primary strategies for climate adaptability focus on ventilation and thermal insulation. The design of Hakka enclosed houses demonstrates that the thermal comfort percentage (TPR) is significantly influenced by factors such as eave height, hall depth, room width, window-to-wall ratio, and wall materials. Key architectural elements affecting ventilation include the hall depth, room width, courtyard depth, eave height, and hall width. The factors impacting thermal comfort are materials, roof thermal transmittance coefficients, room width, eave height, courtyard depth, and roof materials. Daylight levels are primarily affected by the hall depth, eave height, alley width, room width, and window-to-wall ratio. The architectural factors influencing humidity within the enclosed houses include the WWR, materials, external wall systems, roofing, hall depth, and drainage [10,25]. Thus, the principal architectural factors affecting the internal climate of buildings are building width, patio depth, hall depth and width, WWR, eave height, and building materials. Based on the authors’ field surveys, the key architectural elements and their corresponding parameters for the GEH are summarized in

Table 2. Matrix of key architectural elements for the climate adaptability of GEH.

Architectural Elements		Figures (m)
Room Width		2.225, 2.667
Patio Depth		2.889, 3.334, 3.778
Hall Depth		3.810, 4.445, 5.080
Window-to-Wall Ratio		0.02, 0.04, 0.06, 0.08, 0.10
Eave Height		2.790, 3.105, 3.425, 3.741, 4.059, 4.376, 4.694, 5.010
Materials	Wall Materials	Raw Rammed Earth Wall, Raw Earth Adobe Brick, Lime-Rammed Earth Wall, Lime Earth Adobe Brick, Blue Brick Wall, Blue Hollow Brick Wall, Double Corner Brick Wall, Triple Corner Brick Wall, Mixed Wall
	Roof Materials	Grey Roof Tiles, Wood
	Floor Materials	Blue Stone, Pebbles, Rammed Earth

.

3. Research Methodology

3.1. Research Methods and On-Site Measurement Deployment

This study mainly employs a case study, which is a widely recognized and effective methodology extensively utilized in analyzing architectural climate adaptability [23,24]. Architectural adaptability in this study is based on two key factors: longevity and passive survivability [18]. Climate adaptability indicators include wind, thermal, solar radiation/illuminance, and enthalpy–humidity, which significantly contribute to the degradation of building materials, such as the aging of surfaces, delamination of wall insulation, mold growth, and plant-induced structural damage, all of which directly reduce the longevity of architectural adaptability [24,43,44,45,46]. Simultaneously, these indicators may also exceed human comfort zones, including thermal, wind air velocity, visual (illuminance), and humidity comfort ranges, which constitute the foundation of a building’s passive survivability [51]. Computer-based simulations and on-site measurements are effective methods for assessing building adaptability [65,66,67]. To evaluate the climate adaptability of Hakka enclosed houses in subtropical regions and to propose corresponding design strategies, this study selects typical three-hall enclosed dragon house, taking the Guangludi enclosed house (GEH) as a case study. This research first identified the geographic location via the CBE website and climate data, which is the EPW.file from the Energy Plus website and architectural parameters from on-site measurements [40].

Specifically, relevant data and parameters of the Guagnludi enclosed house as a typical three-hall Hakka enclosed house in Meizhou were collected through physical surveys, government reports, and the existing literature. The climate conditions of Meizhou were analyzed using the Energy Plus simulation software and the CBE Clima Tool [40,68,69] (Figure 2). Based on the measured Hakka house data, a digital building model was constructed with Rhino, and simulations were carried out by incorporating Meizhou’s geographic and climatic data into Grasshopper with the use of plugins such as Eddy3D, Ladybug, and Honeybee. These tools enabled the calculation and visualization of building wind ventilation, solar radiation/illuminance, and enthalpy–humidity performance.

The simulation outputs were then compared with on-site measurement data, and both sets of results were evaluated based on human comfort zone criteria to assess the passive survivability of the GEH. By analyzing the discrepancies between simulated and measured parameters, this study further investigates the influence of newly added structures, adjacent constructions, and the local topographical and physical environment, ultimately deriving climate adaptability strategies for Hakka three-hall enclosed dragon houses in subtropical climates.

According to data from the meteorological bureau, Meizhou belongs to the subtropical climate zone, with the hottest climate in summer and the coldest in winter, while other seasons offer relatively good comfort levels. In light of the characteristics of the subtropical climate, the actual measurement times were set for 21 June 2024, and 29 December 2024, which are typical summer and winter days. Four representative time periods in Meizhou were selected for analysis: 3:00–4:00, 9:00–10:00, 13:30–14:30, and 20:00–21:00.

In order to provide a further test of adaptability, 16 inner spots, 13 exterior wall spots, and 12 roof spots of the GEH were identified, arranged from exterior to interior and to the top of the roof. Subsequently, the model-simulated parameters of the GEH were compared with the measured parameters to identify the differences in on-site data with wind, illumination, thermal, and enthalpy–humidity indicators. The causes of the discrepancies between the simulated and measured data and the reasons for building comfort index were arranged to deduce the adaptive design strategies for the three-hall Hakka enclosed dragon house. The specific spots of the GEH case location diagram are shown in Figure 1. Physical observations to test human comfort were arranged as in other studies with 10 participants or more [70,71]. Seventeen participants were initially selected for the experiential evaluation of the GEH case, with ages ranging from 6 to 79 years. However, due to age-related health considerations, the final study included ten participants aged 15 to 61 years. The physical sense results at the spots may have individual differences, but they reflect the real human comfort sense in the GEH. Each participant conducted assessments at four designated time intervals with general clothing in summer and winter, as the daily clothing in winter provides windproof and thermal insulation functions, while in summer, it offers sun protection and heat dissipation capabilities [72,73,74], meeting the testing conditions for building thermal comfort and adopting seasonally appropriate attire. The detailed research process is illustrated in Figure 4. To be specific, step one is problem identification through a literature review. The study began with a critical review of the literature to identify issues related to climate adaptability in vernacular dwellings, particularly under the influence of subtropical climatic conditions. This step also established the conceptual framework and defined the two key evaluative dimensions: longevity and passive survivability. Step two is data collection. A case study with combined methods was employed, including field investigations, on-site measurements, analysis of meteorological data (EPW weather files, CBE thermal comfort standards), and a comprehensive literature review. Parametric design and environmental data processing were primarily carried out using the Rhino and Grasshopper plugins.

The third step is model construction and simulation. Digital models were constructed based on measured building geometry and contextual data. Simulations were conducted to estimate key environmental parameters such as wind flow, solar radiation, air temperature, and humidity levels using Rhino’s Grasshopper plug-ins (Ladybug, Honeybee, and Eddy3D). The simulations covered both standard atmospheric conditions and historically representative climatic scenarios. The fourth step is field measurement and survey. Extensive on-site measurements were conducted to validate simulation outputs. Data were collected from 41 test spots, including 16 interior spots,13 exterior spots, and 12 rooftop spots. Additionally, subjective thermal comfort responses were collected from 10 participants through surveys and interviews, establishing a comparative basis between physical data and human perception.

The fifth step is data comparison and vulnerability identification. A comparative analysis was conducted between the simulated data and measured values to assess the model accuracy and identify discrepancies. This allowed for the identification of vulnerable zones in the building envelope that may contribute to environmental degradation or user discomfort. The two core evaluative dimensions were longevity, which is the assessment of physical vulnerability under environmental stressors, and passive survivability, which is assessment of indoor environmental performance without mechanical intervention, particularly under extreme conditions. The sixth step is adaptive strategy development. Based on the analysis, climate-responsive design strategies were proposed. These included passive interventions such as optimizing ventilation paths, shading devices, roof form adjustments, and window–wall ratios, tailored for seasonal adaptability and improved comfort.

The seventh step is conclusion and synthesis. The study concludes by synthesizing the findings to evaluate the climatic adaptability, environmental resilience, and inhabitation safety of the case study dwellings. The dual-dimensional framework of longevity and passive survivability provides a holistic perspective on performance evaluation, contributing toward the sustainable revitalization of vernacular dwellings in subtropical regions.

3.2. Parametric Analysis

Rhino software possesses robust three-dimensional modeling capabilities and excellent compatibility. Its Grasshopper plugin facilitates parametric design, enabling rapid modification and optimization of architectural models and design schemes, while also supporting rendering and high-quality visualization [75]. Ladybug and Honeybee are open-source tools based on Grasshopper that convert data from epw. files into two-dimensional and three-dimensional graphical representations. These tools have become widely adopted as reliable solutions for simulating solar radiation, building energy consumption, and thermal comfort [76]. Eddy3D is a computational fluid dynamics (CFD) plugin primarily employed for architectural wind environment simulations. It offers advantages such as simplified parameter processing and intuitive graphical representation [68], enabling the analysis of the wind field distribution around buildings and serving as a critical tool for studying architectural wind environments [69]. Additionally, this plugin can simulate wind speed and mean radiant temperature while effectively reducing computational time, balancing flexibility with accuracy [52]. It is commonly applied in building energy efficiency and biophysical research [66,67,75]. This study utilizes Rhino, along with the Grasshopper and Eddy3D plugins, to conduct an in-depth analysis of the wind environment in the Guangludi enclosed house.

A wind frequency rose diagram is a graphical method for statistically representing the frequency of wind direction and speed in a specific region over a defined period. It employs a polar coordinate system where proportional line segments, corresponding to wind speed, are drawn from the center toward each cardinal direction. Connecting the endpoints of adjacent directions forms a closed polygon resembling a rose, hence its name. This diagram visually demonstrates the distribution characteristics of wind direction and speed within the studied area. Natural ventilation has long been a crucial environmental regulation factor in hot climates [77], not only improving thermal conditions but also benefiting human health [78]. In this study, the frequency of natural wind ventilation occurrence is statistically analyzed to emphasize its significance in hot and humid regions.

Architectural lighting includes both indoor and outdoor illumination, with one of the measurement methods being solar irradiance density [79]. Dew point temperature is a significant parameter in meteorology used to describe the humidity state of the air. By monitoring dew point temperature, weather changes, such as the formation of fog, dew, and frost, can be predicted. Dew point temperature is closely related to the relative humidity of the air, which is defined as the ratio of the actual vapor pressure of water in the air to the saturation vapor pressure of water at the same temperature. When relative humidity reaches 100%, the air becomes saturated, and the temperature at this point is the dew point temperature [80]. Thermal comfort refers to the psychological state of satisfaction experienced by occupants regarding their thermal environment, which is achieved by maintaining thermal balance between the body and its surroundings [74,75]. The percentage of thermal comfort serves as an indicator of climate adaptability, with the primary factors influencing thermal comfort being wind speed, humidity, and building design [30,54,67,80,81].

4. Building Performance Module Construction and Performance Analysis

4.1. Wind Environment Analysis

Data on the average wind direction frequency and wind speed over several years for a specific region were obtained from professional meteorological data websites and CBE tool website [38,40]. As explained in the Research Methodology section, this research imported the EPW (Energy Plus Weather) file, which was then was imported into the Grasshopper plugin in Rhino, and extracted the wind direction, dew point temperature, and dry bulb temperature data for further processing. A polar coordinate diagram was created based on the processed data. The calculation process was performed by the professional wind environment visualization tool Grasshopper plugin, and line segments were drawn according to the proportional lengths for each direction, extending from the center to represent the frequency or magnitude of the wind speed in that direction. These lines were connected to form a closed polyline, resulting in a wind rose diagram. Using meteorological bureau data open access figures for analysis, the wind rose diagram for Meizhou indicates that the region generally experiences low wind speeds, with prevailing southeast winds in summer and northwest winds in winter (Figure 5).

The testing period was standardized based on the end of 2024; therefore, the climatic data used in this study refer to the most recent standard year 2023. Climate data were recorded on a 24 h basis for each day throughout the year, and the year was divided into four seasonal periods: 1 January to 31 March, 1 April to 30 June, 1 July to 30 September, and 1 October to 31 December. Visual parameters are illustrated by sequence in Figure 5. According to the wind rose diagram, Meizhou’s wind speeds are primarily observed in summer and winter, and the diagram shows that the wind direction changed with the seasons, which are northwest wind in winter and southeast wind in summer. Therefore, the wind speed calculations for the GEH mainly on the summer and winter seasons (Figure 5).

After constructing the GEH model in Rhino, the climate data for the region were imported by extracting wind direction, location, wind–diffuse temperature, and ground temperature data from the Meizhou winter and summer climate data (EPW.file), followed by an analysis of the terrain and building using the Eddy3D plugin and calculation of the GEH architecture mesh and slides wind speeds with the unit m/s via the CFD progression. The results indicate that during summer, the predominant southeast wind passes through the building, resulting in significantly higher ventilation rates in the N1, N13, N14, N4, N15, N16, N5, N9, and N12 spots compared to other parts of the building (Figure 6). Among these, the N1 Patio and Huatai exhibit the highest ventilation rates (Figure 6). In winter, the ventilation rates in the N1, N13, and N14 areas of the GEH are particularly notable, ranging from 0.5 m/s to 1.8 m/s, while the ventilation rates in the N4, N15, N16, N5, N9, and N12 spots are slightly lower, ranging from 0.2 to 1.5 m/s. Relatively high ventilation rates above 1.8 m/s are observed at the exterior spots E11, E12, E13, E6, and E7. In Figure 6 and Figure 7, it is observed that the ventilation rates in the exterior corners of enclosed rooms on both the interior and exterior sides of the Heping walls and at the corners of walls 1.2 m above the ground level remain consistently low during both summer (Figure 6) and winter (Figure 7).

Based on the actual wind speed measurements in summer, the wind speed on the measured day was lower than that reported by the meteorological bureau. The highest wind speeds occurred between 3:00 am and 4:00 am, with a peak of 1.8 m/s at spot N12, which was lower than the 2.0 m/s wind speed in Dapu, Meizhou. Among the measurement points, E8 and E9 had the lowest wind speeds, remaining below 1.0 m/s throughout the day. In the winter wind speed measurements, the overall wind speeds were lower than the actual level 3 wind speed. The highest wind speeds were still observed at E12, E1, E6, and E7. From the on-site observation, it was found that on the left side, there were newly built corridors with a height of over 3 m at E4, E5, and E6. Near the 1.2 m mark at the locations of E10, E11, and E12, there were residential buildings with a height of over 3.5 m. Behind the positions of E7, E8, and E9, there was Fengshui forest sheltering. As a result, there were wind-blocking shelters on both the left and right sides, and the woods provided wind protection at the back. During the on-site inspection, it was observed that the wall corners formed by E1, E3, E4, E13, and E12 were lined with blue granite, while the rest of the walls were finished with rammed earth and lime white. The blue granite at the wall corners showed no signs of weathering. However, the walls adjacent to the blue granite at the corners had separated from the long stone, and the white lime-finished walls had bulged off, exposing the rammed earth and forming 0.12 m depressions due to significant peeling.

There were marks of rainwater dripping and falling below 0.7 m at spots E1, E2, E3, E4, E12, and E13, which had caused bulging and peeling of the white lime-finished walls. For the walls (spots E4, E5, E6, E7, E10, and E11), the white lime-finished parts above 2.8 m had also developed bulges and peeling due to rainwater runoff. There was no obvious collapse of the entire exterior wall and roof. According to communication with the homeowners, the roofs were inspected and repaired twice a year. However, the owner explained that there was roof damage (in Figure 8) However, the roofs at spots E6, E7, E9, E10, E12, and E13 were the most prone to erosion and crushed, which could be attributed to wind speed. As indicated by both computer simulations and actual measurements, except for spots E9 and E10, these points had the highest wind speeds in both summer and winter. In addition, spots E6, E7, E9, and E10 had semi-circle roofs, which led to uneven stress on the roof purlins.

4.2. Solar Radiation as Lighting and Thermal Analysis

Illuminance (lux) and solar radiation (kWh/m²) serve as two key indicators for assessing thermal conditions. This study obtained the annual solar irradiance energy in Meizhou by integrating field-measured illuminance data with the geographical and climatic data of Meizhou imported into the computer model, with H1–H12 as analysis spots. It indicates the total amount of solar illuminance energy received per unit area and is an indicator of the thermal function in terms of building climate adaptability to analyze the visualized thermal parameters of the three-hall style enclosed Hakka house (Figure 9).

Our research team created a model adopting the Grasshopper modeling software and then imported the EPW (Energy Plus Weather) file. Firstly, the building model to be analyzed was obtained through Grasshopper modeling, followed by the import of the EPW file to incorporate climate and geographical information for the project location in Meizhou. Subsequently, the Honeybee-Generate Zone Test Points component was utilized to integrate model information with environmental data, allowing for the division of grids and calculation points. Honeybee-Run Daylight Simulation was employed to call radiance for computations, while Honeybee_Read Annual Result was used for solar radiation simulation analysis, resulting in a rendered map of cumulative annual solar radiation.

In the indicator visual parameter shown in Figure 9, kWh/m² represents the energy density of solar radiation, that is, the amount of solar energy received per square meter. Based on the data presented in Figure 9, the roof areas H5, H6, H8, H9, and H10, as well as other southeast-facing roofs, exhibit the highest solar radiation densities, ranging from 1764 kWh/m² to 1960.46 kWh/m². In contrast, the solar radiation values on other roofs fall between 980 and 1176.29 kWh/m², while the solar radiation values in the northwest-facing roof areas of all measurement points range from 1176.29 kWh/m² to 1764.44 kWh/m².

There are significant differences in solar irradiance on the open ground surrounding the residential buildings (Figure 9). The solar radiation values at N1, N13, and N14 are between 980 kWh/m² and 1176.29 kWh/m², whereas those at N4, N15, and N16 range from 784.19 kWh/m² to 980 kWh/m². The solar irradiance values on other open ground areas are below 784.19 kWh/m². The order of solar radiation values at different points is N1, N13, N14 > N4, N9, N15, N16 > N2, N3, N5, N6, N7, N8, N10, N11, N12.

Therefore, the roofs significantly block a large amount of solar irradiance. The differences in solar irradiance across various areas within the building are mainly attributed to the scale and angle of shading. Higher walls, along with the spacing and angles between them, affect solar exposure. Due to similar geographical and climatic conditions, the sunny areas receive the highest solar radiation, while the Huatai mound has moderate solar radiation, and other areas have lower solar radiation densities.

4.3. Enthalpy–Humidity Analysis

Utilizing Ladybug and Honeybee, the model of the Guangludi enclosed house and geographical climate data were analyzed (Figure 2), resulting in the export of dew point and dry bulb humidity diagrams (Figure 10), as well as the enthalpy–humidity psychological diagram and annual comfort range diagram (Figure 11). The analysis indicates that the humidity in Meizhou’s Guangludi ranges between 0.001 kgw/kga and 0.025 kgw/kga, with the main humidity concentrated between 0.005 kgw/kga and 0.02 kgw/kga. The temperature varies from −0.2° C to 38 °C, with most values falling between 15 °C and 34 °C (Figure 10).

According to the thermal comfort period distribution illustration in Figure 11, dry bulb temperatures frequently exceed 30 °C, with a specific humidity above 0.015 kgw/kga during midday to late afternoon hours (12:00–18:00) from May to October. In spring (March to April) and autumn (October to November), parts of the daytime hours fall within the comfort zone, with dry bulb temperatures ranging from 20 °C to 26 °C and specific humidity maintained at 0.010–0.014 kgw/kga, conditions that fall within the human comfort zone (Figure 10 and Figure 11). During winter (December to February), although the overall temperatures drop, certain daytime periods (particularly from 3:00 PM to 11:00 PM) still indicate thermal comfort. The dew point, humidity, and temperature data from the chart collectively indicate that Meizhou experiences prolonged periods of high temperature and high humidity, particularly in summer. In winter, from around 12:00 PM through early morning hours, the conditions are characterized by cold and high humidity, with portions of the day falling outside the human comfort zone. Moreover, the mild daytime temperature and moderate humidity levels during winter and early spring create favorable conditions for the growth of fungi and vegetation.

4.4. Thermal Comfort Analysis

This study references the calculation methods for the thermal comfort of occupants in humid regions. The calculation process involves obtaining temperature, humidity, mean radiant temperature, and wind speed from the simulation results provided by software. Different activities in various spaces yield different results. This study focuses on model construction for open spaces such as the lower patio, Huatai mound, Heping ground, patios among the halls, patios on the east between the lateral rooms and between the lateral rooms and enclosed rooms, establishing nine test spots, as the sun radiation and ventilation data showed similarity in both sides of west patios and east patios; so, this was based on the aforementioned algorithms and formulas. A component for calculating the thermal comfort percentage was developed, leading to the final output of the thermal comfort percentage (Figure 12 and Figure 13). The figure illustrates that from mid-December to early February, the period between 14:30 and 20:00 falls within the human comfort zone. From mid-February to the end of February, as well as from mid-March to mid-April and from mid-October to early December, nearly the entire day remains within the human comfort zone. However, from late April to early October, the majority of days fall outside the human comfort zone.

5. Field Measurement Analysis

5.1. Field Measurement Scheme

Given that the most pronounced climate variations in subtropical monsoon climate regions occur between summer and winter, this study selected the middle dates of summer and winter, which are 21 June 2024 and 29 December 2024, respectively, as typical summer and winter dates for data collection. Data were gathered at four distinct time intervals on these days for analysis: the early morning hours with the lowest temperatures (3:00–4:00), the period two hours after sunrise when temperatures begin to rise (9:00–10:00), the time of peak temperature (13:30–14:30), and the period after sunset when temperatures start to drop (20:00–21:00 pm). Linear graphs were then plotted based on the collected data and illustrated via Excel, and the results are shown in Figure 14, Figure 15, Figure 16, Figure 17 and Figure 18 along with the erosion state in Figure 8. The measurement points are numbered starting from “No”. N1–N16 represent the measurement spots inside the Guangludi enclosed house, while E1–E13 denote the measurement spots outside the Guangludi enclosed house. The atmospheric pressure in Meizhou, where the case study is located, ranges from 980.2 hPa to 1015 hPa. For the purpose of the absolute humidity analysis in this study, a standard atmospheric pressure of 1013.25 hPa was adopted. In addition, on the days of field measurements, five participants provided subjective thermal sensation data. The purpose of this data collection was to further assess the thermal comfort levels of the case site under extreme weather conditions during both the winter and summer seasons.

5.2. Temperature and Humidity Measurements at Different Time Intervals and Spots

Based on the temperature measurements taken on the day of observation, during summer, the indoor temperature was relatively stable and high, ranging between 25 °C and 35 °C. The diurnal temperature variation was within 10 °C, with most measurement spots showing a variation of about 5 °C. In contrast, the outdoor temperature variation during the main time intervals was between 10 °C and 12 °C. The temperature variations at N6 and N10 were within 6 °C, indicating relatively small fluctuations, with temperatures ranging between 25 °C and 30 °C; other points had higher temperatures. The temperature difference between the lower patio and the subsequent Huatai mound was relatively large during summer, while the temperature differences within other indoor areas were smaller. Moreover, indoor temperatures were approximately 5 °C lower than outdoor temperatures, ranging between 25 °C and 30 °C, providing a relatively comfortable thermal environment for humans. As shown in Figure 14, the measured indoor temperatures during winter ranged between 8 °C and 17 °C. The temperature spans at spots N1, N2, N3, N13, N14, N7, and N16 were relatively large, with a difference of 8 °C, while the temperature differences at other points were within 5 °C. Outdoor measurement spots exhibited larger temperature variations, with differences of approximately 11 °C among all spots.

During the lowest temperature period of 3:00–4:00, the temperature inside the GEH ranged between 24.6 and 26.9 °C, with relative humidity between 47.1% RH and 54.3% RH, and absolute humidity between 0.009 and 0.010 kgw/kga. The temperature outside the GEH ranged between 24.6 and 26.8 °C, with relative humidity between 48.9% RH to 65.1% RH, and absolute humidity between 0.009 and 0.013 kgw/kga, as illustrated in Figure 14.

During the period of 9:00–10:00, as shown in Figure 19, the temperature inside the GEH ranged between 27.1 and 32 °C, with relative humidity between 41.3% RH and 60.5% RH, and absolute humidity between 0.013 and 0.015 kgw/kga. The temperature outside the Guangludi enclosed house ranged between 27.7 and 30.9 °C, with relative humidity between 46.9% RH and 63.1% RH, and absolute humidity between 0.013 and 0.016 kgw/kga.

During the highest temperature period of 13:30–14:30, the temperature inside the Guangludi enclosed house ranged between 29.5 and 34.4 °C, with the relative humidity parameter of 37.5–50.5% RH, and absolute humidity between 0.012 and 0.015 kgw/kga. The temperature outside the GEH ranged between 27.9 and 34.2 °C, with relative humidity between 39.3 and 57.2% RH, and absolute humidity between 0.012 and 0.016 kgw/kga, as presented in Figure 14.

During the temperature declining period of 20:00–21:00, the temperature inside the Guangludi enclosed house ranged between 25.3 and 30.4 °C, with relative humidity between 39.2% RH and 53.4% RH, and absolute humidity between 0.010 and 0.013 kgw/kga. The temperature outside the GEH ranged between 27.7 and 30.9 °C, with relative humidity between 40.3% RH and 56.1% RH, and absolute humidity between 0.011 and 0.013 kgw/kga.

In summer, the measured relative humidity data indicate that indoor measurement points generally ranged between 38 and 67% RH. At points N1, N2, N3, N15, and N16, relative humidity ranged between 38 and 55% RH, while at other points, it ranged between 47% RH and 60% RH. Outdoor data indicated that the humidity differences between morning and evening at points E9, E10, and E13 were as large as 20% RH, with humidity ranging between 40 and 67% RH, as shown in Figure 14.

In winter, relative humidity measurements revealed that at 9:00–10:00, the relative humidity differences among all spots were relatively small, not exceeding 5% RH. However, the humidity variations between morning and evening at spots N1, N2, N3, N14, N13, N15, and N16 were relatively large, with a difference of 30% RH. At other spots (N4, N5, N6, N7, N8, N9, N10, N11, and N12), humidity variations were smaller during other time intervals, with a difference of 13% RH, and humidity ranging between 52 and 70% RH, as illustrated in Figure 14.

The summer measurements results illustrated in Figure 15 show that the absolute humidity at indoor measurement spots ranged between 0.009 and 0.014 kgw/kga, and there were no significant differences in absolute humidity among these spots. The absolute humidity outdoors ranged between 0.010 and 0.017 kgw/kga. Among the outdoor spots, E13 exhibited the largest diurnal variation in absolute humidity. The variation in absolute humidity was smaller indoors compared to outdoors in winter. The absolute humidity values at both indoor and outdoor measurement points ranged between 0.040 and 0.060 kgw/kga. At spots N1, N13, N14, N15, and N16, the absolute humidity changes were minimal, within 0.014 kgw/kga. For other spots, the diurnal absolute humidity variations were within 0.026 kgw/kga. Exterior spots, the absolute humidity at E13 ranged between 0.0047 and 0.0049 kgw/kga, showing very little variation within 0.001 kgw/kga. E6 exhibited the largest variation in absolute humidity, with a difference of 0.002 kgw/kga.

5.3. Illuminance and Wind Measurements at the Spots

From the perspective of illuminance during summer, the daily illuminance levels at spots N1, N2, N13, N14, N15, and N16 exhibited significant variations. The highest illuminance, reaching nearly 91,000 lux, was recorded during 13:30–14:30, while the lowest illuminance was observed at spot N9. The illuminance at spots N5, N16, N17, N8, N9, N10, N11, N12, and N13 remained below 72,000 lux.

In winter, the spot with the largest illuminance span during the daytime was N13, which experienced a rapid decrease in illuminance between 8:00 and 9:00, shortly after sunset. The illuminance at spots E11 and E12 was notably higher than at other locations during the period of 9:00–14:30, reaching up to 125,000 lux in exterior spots. For all the tested spots within GEH, the illuminance levels remained between 84 and 200 lux during the evening in summer before 9:00 pm. In contrast, during the same time period in winter, the illuminance parameter at all tested spots was essentially between 0 and 2 lux, as visually illustrated in Figure 16.

The seasonal variations in measured wind speeds across both inner and exterior spots are illustrated in Figure 17. The results show that the inner spots suffer from generally low ventilation rates, especially between N4 and N12, where both summer and winter wind speeds drop below 0.3 m/s. In contrast, exterior spots such as E1–E3, E6–E8, and E11–E13 exhibit stronger airflow, exceeding 1.5 m/s in some cases during winter. These findings confirm that enclosed courtyard configurations significantly reduce cross wind ventilation, increasing the risk of mold and material decay in shaded and poorly ventilated zones. The seasonal variation also indicates better passive cooling potential in the exterior zones during summer, but insufficient airflow inside highlights the need for design interventions like vertical ventilation shafts or operable clerestory windows.

5.4. Comfort Assessment of Measurement Spots Based On-Site Physical Sensor Tests

In the summer on-site measurement results shown in

Table 3. The comparison of comfort zone factors among model stimulation parameters, field-measured parameters, and recommended standard parameters.

Indicator	Model Simulation Parameters	Field-Measured Parameters		Comfort Zone Parameters
		Inner Spots	Exterior Spots	Recommened Standard	Comparison
Thermal (°C)	Mainly 5–38 Rarely between 0 and 5	Summer: 25–35	Summer: 25–35	18–25	Model and measured parameters are over the hot temperature comfort zone.
		Winter: 8–17	Winter: 7–18	20–27	Model and measured parameters are lower than the hot temperature comfort zone.
Relative Humidity (%)	Mainly 30–80 Rarely 20–30, 80–90	Summer: 38–62	Summer: 36–65	25–60	Both model parameters are over the 20% humidity comfort zone.
		Winter: 38–69	Winter: 49–78	25–60	Both over 9-18% humidity comfort zone over the comfort zone
Abosolute Humidity (kgw/kga)	Mainly 0.005–0.02 Rarely 0.002–0.005, 0.02–0.025	Summer: 0.010–0.014	Summer: 0.010–0.018	0.008–0.014	Measured parameters at the inner spots are in the comfort zone and at exterior spots are over the 4 kgw/kga humidity comfort zone.
		Winter: 0.003–0.006	Winter: 0.004–0.006	0.008–0.14	Mesured inner and exterior paramenters are lower than the humidity comfort zone of 2 kgw/kga–4 kgw/kga
Solar	Radiation (kwh/m2) South roof: 1176–1960 kwh/m2, North roof: 800–1176, Southeast roof: 1176–1764	Solar lighting (lux) Summer: 40,000–90,000	Solar lighting (lux) Summer: 60,000–130,000	>300lux >8 h >60% space, below 100,000 lux.	Summer: lighting over the visual comfort zone, Winter: in the visual comfort zone. Winter: lighting on the first floor rooms at spots N2, N4, N6, N7, N8, N9 and N10 in winter has 8 h shorter than the comfort zone, and less than 60% square.
		Solar lighting (lux) Winter: 2000–14,000	Solar lighting (lux) Winter 60,000–14,000	>300 lux >8 h >60% space, below 100,000 lux.	Radiation: N2, N4, N5, N6, N7, N8, N9, and N10 between 392 and 980 kwh/m2, which is less than N1, N13, N14, N4, N15, and N16; the south roof is more than the north roof and southeast roof.
Wind (m/s)	Summer: 0.001–2.1	Summer: 0.001–1.6	Summer: 0.001–1.8	0.8–3.0 m/s	The model parameter wind is slightly higher than the measured parameter. Need more wind in summer.
	Winter: 0.001–2.6	Winter: 0.001–2.5	Winter: 0.001–2.6	<1 m/s	The model parameter wind is the same as the measured parameter.

, the ten participants of the research team reported a consistent sensation of heat and discomfort at all inner spots locations from 10:00 to 21:00. Whether at rest or in motion, perspiration was frequent, regardless of wearing cotton or polyester clothing. Interior lighting was perceived as harsh and glaring. Between 03:00 and 06:00, conditions were significantly more comfortable, with a light breeze and favorable temperature and humidity levels. Light levels remained below 100 lux, creating an ideal environment for sleeping indoors and visual comfort outdoors. From 07:00 to 10:00, at locations N2 through N12, subjects experienced mild heat when stationary with no sweating; however, light activity still induced perspiration. These conditions were considered tolerable. Similarly, spots N1 and N13–N16 also registered as slightly warm yet bearable. Indoor lighting was comfortable, although several points experienced excessive brightness.

In on-site measurements, all the participants expressed the comfort feeling of cold during the whole 24 h cycle across inner spots in winter. While humidity levels were slightly dry, they remained within acceptable limits, and lighting was generally comfortable. From 10:00 to 14:30, even while wearing heavy winter coats as general local people, the thermal sensation was still cold but tolerable for the participants.

As for the exterior spots during summer, the 01:00–05:00 interval provided the most thermally comfortable conditions, with a light breeze, appropriate humidity, and temperatures perceived as pleasant. Light levels remained below 100 lux, albeit slightly humid. From 05:00 to 08:00, locations E4, E5, and E6 presented visually comfortable lighting, while other spots were perceived as glaring. Thermal conditions were mildly hot yet tolerable, with humidity remaining within a comfortable range. Between 10:00 and 20:00, lighting was reported as excessively bright, and high temperatures led to profuse sweating. However, between 18:00 and 20:00, visual comfort improved across most locations, except at E8–E12, where low illumination compromised visibility. From 20:00 to 01:00, temperatures remained slightly warm but within tolerable limits, and low light levels created a favorable environment for sleep. During winter, the exterior spots remained cold throughout the entire 24h period. Between 10:00 and 14:30, at locations E9, E10, and E12, subjects reported feeling cold but tolerable even while wearing insulated jackets. At other points, engaging in light physical activity for approximately 10 min was sufficient to achieve thermal comfort.

6. Discussion

6.1. Discussion of the Measurement Spot Results

The analysis results indicate that the wind speed in the GEH and its surroundings is generally low. Southeast winds prevail in summer, while northwest winds dominate in winter (Figure 6). The erosive effect of wind on buildings is minimal, with little variation observed. The lower patio, associated with spots N1, N13, and N14, is characterized by high wind speeds, a strong annual heat dissipation capacity, high solar radiation density, high humidity, and abundant sunlight (Figure 5). The annual solar radiance in this area reaches a maximum of approximately 1765 kWh/m², with a minimum of 980 kWh/m², which is significantly higher than that of the Huaitai mound area (580–980 kWh/m²). The difference in solar irradiance between the two areas is about 800 kWh/m², as observed at test spots N4, N15, and N16. In summer, the illuminance ranges from 45,000 lux to 91,000 lux, while in winter, it ranges from 8500 to 13,000 lux. The temperature difference between pre-dawn and afternoon is the largest in this region. Summer temperatures generally range between 25 and 35 °C while winter temperatures range between 8 and 15 °C. Summer absolute humidity ranges from 0.010 kgw/kga to 0.015 kgw/kga, and winter absolute humidity ranges from 0.004 kgw/kga to 0.006 kgw/kga. The relative humidity difference between morning and evening in summer is relatively small, with summer relative humidity ranging from 38% RH to 59% RH and winter relative humidity ranging from 38% RH to 68% RH. In winter, there is a significant difference in relative humidity between morning and evening troughs. Measured wind speeds at inner spots show that the lower patio (N1, N14, and N13) experiences wind between 3:00 and 4:00 am, with wind speeds <1.0 m/s during other times. In winter, wind speeds vary more, ranging from 0 to 2.5 m/s.

For the upper patio, middle patio, left upper patio, right upper patio, left middle patio, and right middle patio, model simulation parameters indicate that the annual irradiance is below 800 kWh/m². Both stimulation parameters and measured data show that these areas are hot in summer and cold in winter, with little differences in thermal, humidity, and solar illuminance. The temperature range in summer is approximately 25 °C to 32 °C, with a temperature difference of about 17 °C, while in winter, it is 9 °C to 16 °C, with a temperature difference of 7 °C. Measured data show that the relative humidity difference throughout the year is within 10% RH, with maximum values occurring in summer and winter (Figure 13). Summer relative humidity ranges from 38% RH to 60% RH, and winter relative humidity ranges from 38% RH to 68% RH. Winter relative humidity reaches 30% RH throughout the day, with a significant difference of 20% RH between pre-dawn and post-dawn. The daily relative humidity difference in summer is within 15% RH (Figure 14). The daily absolute humidity difference in summer is 0.006 kgw/kga, ranging from 0.009 kgw/kga to 0.015 kgw/kga, while in winter, it is 0.003 kgw/kga, with absolute humidity ranging from 0.0035 kgw/kga to 0.0065 kgw/kga (Figure 15).

In the period from 9:00 to 14:30, the GEH receives the most sunlight in summer, with illuminance ranging from 38,000 lux to 75,000 lux, while in winter, it ranges from 700 lux to 14,000 lux during the corresponding period (Figure 16). From the analysis of the illumination curve, it is evident that solar radiation reaches its peak intensity during the summer months, with minimal fluctuations in irradiance levels observed from sunrise until the afternoon. Conversely, the diurnal illumination pattern in winter exhibits pronounced variability throughout the day. The south-oriented rooftops of H6 and H7 demonstrate the zenith of solar irradiance, with values oscillating approximately between 1764 and 1960 kwh/m². The south-facing rooftops of H5, H8, H9, and H12 exhibit a secondary tier of elevated irradiance, ranging from 1370 to 1764 kwh/m², while the remaining areas register comparatively lower irradiance readings. Given the direct relationship between solar irradiance intensity and the resultant wall surface temperature, the walls corresponding to inner spots N12 and N11 attain the pinnacle of thermal elevation. This is succeeded by the south-oriented walls of N6 and N7, which manifest a relatively elevated temperature profile. The north-facing walls of N9 and N10 occupy the subsequent stratum in terms of temperature magnitude. The walls in other locations exhibit comparatively lower temperatures, commensurate with their diminished solar irradiance exposure.

In the Huaitai mound area (N4, N15, and N16), computer simulation parameters indicate that annual solar irradiance ranges from 580 kWh/m² to 980 kWh/m². Measured illuminance data show that solar illuminance at these building spots ranges from 4500 lux to 9100 lux in summer and from 1100 lux to 14,000 lux in winter. The difference in sunlight parameters between winter and summer is significant, with a shorter sunlight duration in winter. Measured data show that daily temperatures in summer range from 25 °C to 32 °C, with significant temperature differences between 9:00 and 10:00 am post-dawn and 8:00 and 9:00 pm post-sunset. In winter, measured daily temperatures at the Huaitai mound spots range from 8 °C to 13.5 °C, with smaller temperature differences between the same time periods. Summer relative humidity ranges from 44% RH to 55% RH, and winter relative humidity ranges from 44% RH to 65% RH. The relative humidity difference in summer is small, while in winter, it is large. Absolute humidity shows little variation throughout the year, ranging from 0.010 kgw/kga to 0.014 kgw/kga in summer and from 0.004 kgw/kga to 0.006 kgw/kga in winter. The Huaitai mound area (N4, N15, and N16) experiences wind between 3:00 am and 4:00 am, with wind speeds < 0.1 m/s during other times.

Measured wind speeds at inner spots show that the lower patio (N1, N14, and N13) experiences wind between 3:00 am and 4:00 am in summer, while the upper patio (N4, N15, and N16) also experiences wind during the same period, with wind speeds < 0.1 m/s during other times. In winter, wind speeds at the lower patio (N1, N13, and N14) vary at different times, generally fluctuating below 1.5 m/s. Wind speeds at other spots show significant differences.

Based on the on-site measurement data collected at all exterior spots of the GEH, taken at a distance of 0.5 m from the surrounding walls, several key observations were made. During the summer, the temperature at points E6, E9, and E10 ranged from 25 °C to 34 °C. The temperature profiles at these locations were relatively flat, indicating minimal temperature fluctuations. In contrast, the winter measurements showed a wider temperature range between 7 °C and 19 °C, reflecting more significant diurnal variation. Specifically, E6 and E10 maintained temperatures between 26 °C and 31 °C, which were slightly lower compared to other locations. Notably, the temperature at E9 remained consistently stable between 26 °C and 27 °C throughout the day. During winter, E9 also exhibited limited variation, with temperatures ranging from 9 °C to 16 °C.

Regarding absolute humidity, measurements at E6 and E10 ranged from 0.010 kgw/kga to 0.065 kgw/kga in summer. In winter, E1 and E13 showed relatively stable humidity levels, ranging from 0.0040 kgw/kga to 0.0065 kgw/kga, with minimal fluctuation. Illumination measurements during summer indicated high solar exposure between 9:00 and 14:30, ranging from 6000 lux to 130,000 lux. In winter, illumination during the same period ranged from 6000 lux to 140,000 lux, but the duration of high illumination was shorter. Spots E3 and E4 received the best solar exposure in summer, with E12 having the highest illumination and longest duration of light. In winter, E3 exhibited minimal variation in illumination, remaining around 140,000 lux, while E11 showed greater variability in solar exposure during 9:00–14:30.

Among all the exterior spots, points E1, E2, E3, E4, E11, E12, and E13 recorded higher ground-level irradiance throughout the year. In contrast, other exterior spots were partially shaded due to various obstructions and additional built structures near E5 and E11; Fengshui forest near E7, E8, and E9; and tree shadows affecting E6 and E10. Rooftop irradiance was also analyzed, revealing that the south-facing roofs at points H6, H7, H8, H9, H10, and H15 received significantly higher solar radiation (1700 kWh/m² to 1960 kWh/m²) compared to the north-facing roofs (800 kWh/m² to 1100 kWh/m²), with a difference of over 700 kWh/m².

The highest exterior wall surface temperatures were recorded at E10, E11, and E12. Wind speed measurements (Figure 6) revealed that during summer, wind speeds at E8 and E9 remained below 0.1 m/s throughout the day. At other points, wind was observed between 20:00 and 04:00 the following morning, with speeds reaching up to 1.8 m/s. Wind speeds at E5, E6, E7, E8, E11, E12, and E13 remained generally below 1.0 m/s. In winter (Figure 7), spots E2, E3, E5, E6, E7, E8, E9, and E10 exhibited wind speeds below 0.01 m/s during 13:30–14:30. However, point E1 recorded a winter wind speed of 1.2 m/s, and points E2, E3, E4, and E5 experienced wind speeds greater than 1.2 m/s between 3:00 and 4:00 am and again during 13:30–14:30.

The comparison between simulated solar irradiation and on-site measured illumination further confirmed disparities among different exterior spots. These differences were mainly attributed to the presence of additional built structures and the Fengshui forest, which caused varying degrees of shading and affected solar radiation levels across the site.

6.2. Wind Environment Parameter Comparison and Environmental Adaptability Evaluation

Based on simulated and measured wind direction and velocity data, the overall wind intensity of the GEH remains relatively low throughout the year, with prevailing southeasterly winds in summer and dominant northwesterly winds in winter (Figure 6). However, even subtle variations in wind speed (generally below 1.5 m/s) can significantly influence environmental adaptability, spatial utilization efficiency, and seasonal thermal comfort strategies.

In summer, the lower patio (N1, N13, and N14) benefits from persistent yet gentle southeasterly airflow during the early morning (3:00–4:00), facilitating latent heat dissipation and reducing nocturnal humidity. However, daytime wind speeds generally remain below 1.0 m/s, leading to heat accumulation and thermal discomfort. This phenomenon suggests the need for architectural adaptive measures: expanding southeastern window openings, installing adjustable louvers, or increasing WWR to promote cross-ventilation. Simultaneously, vegetation shading and extended eaves should be arranged in the southeastern corners (N13 and N14) to block solar radiation while preserving ventilation potential.

In winter, simulated wind speeds at points such as N6 and N7 slightly exceed 2.0 m/s, but the measured values average only 1.3 m/s due to obstructions from windbreak forests and surrounding structures. Such moderate winter winds, coupled with reduced absolute humidity (0.004–0.0065 kgw/kga), help prevent condensation and mold growth on exterior walls in semi-exposed areas like N10 and N11. However, inner courtyards (N9 and N10) and outer corners (E8 and E9) exhibit persistently stagnant airflow year-round, sustaining high humidity levels that trigger biodeterioration, including fracturing, bulging, and molding (Figure 8).

The wind environment also defines human activity zoning: comfortable wind speeds of 0.5–1.5 m/s at points such as N1, N13, and E12 are suitable for outdoor activities like cooking, laundry, and social interaction, whereas airflow stagnation zones like N9, E8, and E9 are characterized by dampness and low utilization rates. Accordingly, functional spaces should be differentially arranged: communal and transitional areas should be located in well-ventilated spots (N13 and E12), while resting spaces should be placed in sheltered and thermally stable areas such as N5 and the northwestern corners of lower courtyards.

From a passive survivability perspective, the wind environment aids both summer physiological cooling and winter humidity control. In summer, the elongated patio between N5 and N6 forms a micro wind corridor with speeds of 0.6–1.2 m/s, alleviating daytime temperatures of 32–35 °C. In winter, chimney-effect ventilation through high clerestory windows or roof vents can facilitate humidity exchange, avoiding discomfort from drafts in living areas.

6.3. Solar Radiation Parameter Comparison and Environmental Adaptability Evaluation

Based on both the simulated and measured data of annual solar radiation, illuminance, and surface temperature, the GEH exhibits distinct seasonal and spatial variations in solar absorption and heat accumulation. These differences have direct implications for building longevity and passive survivability, particularly in Meizhou’s hot-humid subtropical climate.

During the summer months, southeast-facing areas such as N13, E11, and H6 receive the highest solar radiation, with annual irradiance levels exceeding 1170 kWh/m² and peak daytime illuminance reaching 38,000–75,000 lux. These zones benefit from rapid surface drying, thereby reducing risks of mold growth and surface weathering—positively contributing to material longevity. However, without adequate shading strategies, high solar exposure may result in indoor overheating. Recommended mitigation measures include wide eaves, vegetative shading, and adjustable louver systems, which can balance natural lighting and ventilation while minimizing direct heat gains.

In contrast, shaded or north-facing areas such as N4, N5, and N6 maintain consistently low annual irradiance levels, generally below 800 kWh/m², with wintertime illuminance often falling below 1500 lux. These conditions promote moisture accumulation, fungal growth, and insufficient daylight, thereby diminishing both thermal comfort and material durability—especially during winter months when sunlight is scarce and air circulation is poor. Biological degradation signs such as cracking and spalling have been observed on wall surfaces near E8, E9, and N10, and are closely associated with low solar exposure (Figure 16).

From a passive thermal design perspective, patio configurations significantly influence solar gain and thermal stability. Compact shallow patios (N5, N7, N10, and N12) exhibit reduced heat retention and enhanced thermal comfort, particularly when combined with appropriately oriented openings. Simulation data indicate that square courtyards with a depth of approximately 2.8–3.0 m provide an optimal balance between solar access and ventilation.

For poorly lit zones, it is recommended to incorporate translucent roof tiles, light tubes, and clerestory windows to enhance winter solar illuminance while enabling adjustable shading during summer. For overheating-prone areas (N16 and N13), reflective exterior coating, ventilated thermal insulation roofs, and low emissivity glazing are recommended to effectively regulate indoor thermal loads.

6.4. Enthalpy–Humidity Psychrometric Parameter Comparison and Environmental Adaptability Evaluation

To assess the adaptability of the GEH, an enthalpy–humidity psychological diagram was constructed based on annual measurements and simulations of temperature and humidity conditions. The results indicate that the region experiences persistently hot and humid conditions throughout the year, especially from May to September, posing significant challenges to both occupant comfort and building preservation.

During summer, absolute humidity ranges between 0.010 kgw/kga and 0.015 kgw/kga, with diurnal fluctuations reaching up to 0.006 kgw/kga (see Figure 13). In the early morning (6:00–8:00) and evening hours (18:00–21:00), air temperatures often approach the dew point, with relative humidity exceeding 80%. In poorly ventilated zones such as N9, E5, and N10, these conditions frequently result in surface condensation, accelerating material deterioration and exacerbating indoor dampness factors that are detrimental to building longevity.

In winter, absolute humidity decreases slightly to a range of 0.0035–0.0065 kgw/kga; however, interior patios and shaded corners (E8 and E9) still exhibit relative humidity above 68% RH due to inadequate air movement. While lower temperatures may suppress microbial growth, high humidity continues to promote mold formation, lime bubbling, and salt efflorescence—conditions particularly damaging to rammed earth walls.

The enthalpy–humidity parameter analysis reveals that the majority of data points fall outside the human comfort zone, occupying high-humidity zones, especially during summer. Nevertheless, during transitional months (October to December and February to April), outdoor conditions intermittently fall within the comfort range defined as 25.2 °C and 30–70% RH. These periods represent windows of opportunity where natural ventilation can serve as an effective passive cooling strategy.

6.5. Comparison of the Results

From practical observations, as depicted in Figure 8 regarding the current state of the exterior walls, the primary issues observed include cracking, wall foaming, spalling, plant growth, and mold formation. In the case of E4, there is a cyan granite section where a gap has formed between the granite and the rammed earth wall, with a width of nearly 7 cm and depths ranging from 5 to 18 cm, accompanied by wind erosion and spalling of the rammed earth. At E5, there is a section where ferns have grown, with moss developing below 1.5 m and concurrent peeling of the white lime layer. Cracking is observed at E6 and E7. Below 2.8 m at E8, there are mottled molds with bulging surface lime layers. At E9, irregular cracks extend from the ground up to 5.3 m, with mold growth observed over a nearby 1.6 m stretch. Additionally, there are two more cracks between E9 and E10. At E1, there is mold growth up to 0.90 m. Mold and spalling phenomena are also observed on the southern and southeastern faces of N13 and N14 in the lower patio, the northwest corners of all patios, as well as the northwest and southeast corners of the Huatai Mound. Widespread structural deterioration was identified at spots E4, E5, E6, E7, E9, E10, E11, E12, E13, N1, N2, N4, N7, N8, N14, N15, and N16, where fractures in purlins and missing roof tiles were evident. Particularly, the rooftops at E6, E7, E9, and E10 constructed as circle roofs atop patio walls, present a higher concentration of structural vulnerabilities due to the complexity of overlapping joints. In these areas, aside from deficiencies in roofing techniques, exposure to strong prevailing winds, wind-driven rain, and long-term wind erosion has significantly accelerated material degradation.

Natural influencing indicators for architectural longevity that comprise the degree of natural erosion are humidity, thermal, wind, and solar radiation. These metrics were employed to systematically classify the 16 interior measurement spots and 13 exterior measurement spots of the GEH. Furthermore, structural longevity assessments integrate roofing materials and construction integrity, including supplementary roof monitoring locations (H1–H12). A holistic evaluation was performed to determine the relative risk levels pertaining to long-term structural resilience, with the results tabulated in

Table 4. Longevity risk assessment of inner and exterior spots of the GEH.

Spots	Location	Key Environmental	Features Longevity Risk Indicators	Longevity Risk Level
N1, N13, N14	Lower patio	High wind speed, high humidity, high solar exposure	Wall erosion due to wind-driven rain and solar aging; bio-growth	High
N2-N3, N5–N6, N7–N12	Lateral rooms	Low wind speed, moderate solar, high humidity	Poor ventilation, fungal/mold growth, moisture accumulation	Moderate
N4, N15, N16	Huatai mound area	Low solar radiation, high humidity, poor ventilation	Moisture retention, fungal growth, low airflow	High
H1–H3, H6–H12	Roof spots	Varying exposure to sunlight and rain	Erosion of tiles, structural stress from unequal loads	Moderate
E1–E3	Exterior of the lower patio	High rain pressure, low solar radiation	Bubbling, cracking from wind-driven rain and moss	Moderate
E4–E7	Exterior of northern enclosed rooms	Moderate humidity, some shading	Rain runoff, lime peeling above 2.8 m, structural stress	Moderate
E8–E10	Exterior of rear enclosed rooms	Very low wind speed, dense vegetation shading	High fungal intrusion, moisture saturation, wall bulging	Extremely high
E11–E13	Exterior of southern enclosed rooms	Wind-sheltered by new buildings, poor drainage	Microbial damage, detachment of lime finish, bulging walls	High

. Descriptive levels as excellent mean that the structure is fully within comfort zone across most indicators, while good means slight deviations in one or two parameters, but generally comfortable. Moderate means mixed results, with noticeable discomfort in some periods. And poor indicates that the structure is consistently outside the comfort zone, which is problematic for prolonged use (Table 4 and

Table 5. Passive survivability assessment of inner and exterior spots.

Spots	Location	Thermal Comfort (TPR)	Humidity and AH	Wind Comfort	Lighting	Passive Survivability Level
N1, N13, N14	Lower patio	Short hot time in summer and cold time in winter	Comfort	Good; summer breezes, light winter winds	Comfort	High
N2–N3, N5–N6, N7–N12	Lateral rooms	Hot in summer, cold in winter, still bearable Fluctuates seasonally	High in summer, moderate in winter	Insufficient wind speed, stuffy	Summer > 3000 lux (too glaring), moderate in winter	Moderate
N4, N15, N16	Huatai mound area	Hot in summer daytime, cold in winter, still bearable	High humidity, slow wind and low ventilation	Slow wind, poor ventilation	Bright in summer, dim in winter	Moderate
H1–H3, H6 –H12	Roof spots	Unbearable over hot, not suitable for living	Comfortable humidity but insufficient light	Strong wind risk	Intense light in summer (8 h), large seasonal variation, short bright periods	Extremely low
E1–E3	Exterior of lower patio	Affected by rain/heat	High heat radiation, unsuitable for comfort	Moderate–low wind speed	Excessive light (>90,000 lux)	Moderate
E4–E7	Exterior of northen enclosed rooms	High humidity, large day-night temperature gap	High humidity, large day–night thermal differece	Cold with a low wind speed	High brightness but strong contrast Strong light in summer, comfortable in winter	High
E8–E10	Exterior of rear enclosed rooms	Hot, humid, stuffy	Over humidity at morning due time, Extremely high humidity, sticky heat	Very poor wind < 0.1 m/s	Low brightness, long–term shaded area	Low
E11–E13	Exterior of southern enclosed rooms	High humidity but large day-night temperature swings	High humidity but large temperature swings	Low wind speed, poor ventilation	High brightness in summer, low in winter	Moderate

).

The annual time proportion within the thermal comfort zone (thermal comfort duration, TPR) serves as a critical metric for evaluating passive survivability measured as the thermal environmental comfort dimension in dwellings. This study assesses the thermal comfort performance of the GEH in 2023 and 2024, through on-site measurements and integrated simulations using Rhino + Ladybug + EnergyPlus. The TPR criteria were defined as 18–25 °C in summer and 20–27 °C in winter [82], with a three-tier evaluation system applied for zoning: high (green, TPR ≥ 40%), moderate (yellow, 30% ≤ TPR < 40%), and low (red, TPR < 30%). The results are shown in Figure 19.

The analysis reveals that the optimal thermal comfort zones are predominantly distributed in the lower patio (N1, N13, and N14) and the northwestern façade of Heping (E1–E3), where the TPR exceeds 40%, indicating prolonged and stable maintenance within the comfort temperature range (Figure 19). The poorest thermal performance occurs in the middle/upper patio (N2–N3), northeast-side rooms adjacent to the middle patio (N9–N10), and enclosed exterior walls from the northeast to southeast corners (E6–E10), with a TPR below 30%, primarily due to prolonged exposure to extreme temperatures for humans. Transitional areas between these zones exhibit moderate comfort levels (30–40% TPR). The results evaluates the significant correlation between the spatial layout and microclimate, providing data-driven support for passive design optimization. In the building interior, measurement points N2–N3 represent the spots with the longest distance from the outermost exterior walls, while N9–N10 are deep-plan spots located on the northwestern side with substantial distances from exterior walls. In the surrounding outdoor environment, the lowest thermal comfort levels are frequently observed in the open northwestern spaces of the lower patio (N1, N13, and N14) and the northwestern wall of the Heping ground (E1–E3).

7. Adaptability Strategies

7.1. Longevity

Based on the key passive survivability and longevity factor of building physical adaptability [39,44,46], this study analyzes climate indicators and the physical longevity of buildings. Appropriate wind ventilation can effectively reduce humidity levels and inhibit mold growth [47]. However, high humidity can lead to the expansion, softening, and fracturing of purlins, or molding of surfaces and structures. Factors such as the spatial layout, window and door dimensions, building materials, and orientation significantly influence the thermal environment, humidity, wind ventilation, and solar radiation/illumination conditions of the building [24,43]. Based on the comparison between measured data and simulation results, notable differences are observed in the longevity strategies for the GEH, indicating that design and preservation measures must be adjusted according to actual environmental responses and performance. By integrating modeling of simulated parameters, visual simulations, actual measurement data, and on-site observation of erosion spots, this study aims to identify the vulnerable architectural components of the three-hall enclosed house under subtropical climatic conditions and to propose appropriate conservation strategies.

The on-site observations of exterior wall conditions reveal widespread deterioration, including structural cracking, bulged, spalling, vegetative growth, and mold formation (Figure 18). At spot E4, a gap measuring approximately 7 cm in width and 5–18 cm in depth has developed between the green granite blocks and the adjoining rammed earth wall, accompanied by signs of wind erosion and material loss. At point E5, ferns are growing on the wall surface, and moss is present below 1.5 m, with visible spalling of the white lime finish. Cracking is observed at spots E6 and E7. At point E8, mottled mold spots appear below 2.8 m, and the surface lime layer shows signs of bubbling. Point E9 features an irregular crack extending from the ground up to 5.3 m, with mold growth spreading across a 2.6 m radius. Two additional cracks are also noted between E9 and E10. Mold growth reaches up to 0.9 m in height along the wall surface at spot E1. Furthermore, mold and spalling are also evident on the southern and southeastern corners of N13 and N14, in the northwest corners of various courtyards, and in the northwest and southeast corners of the Huatai mound.

According to the observed building damage points, as shown in Figure 16, the most deteriorated areas of the exterior walls are located at the rear enclosed rooms. On the north-facing side, damage was concentrated around points N4 and N5. Although these points are exposed to comparable wind intensities in both summer and winter, the presence of a carport and a tree line located 2.5 m from the exterior wall provides windbreak effects, thereby reducing both wind erosion and the vertical reach of rainfall impact. While wind speed simulations indicated that points N6 and N7 experience winter wind speeds exceeding 2.1 m/s, actual measurements showed lower values around 1.3 m/s—evidence that the structures and the Fengshui forest behind also buffer wind impact. However, these corner wall segments remain prone to structural stress, making them more susceptible to cracking and wind erosion.

Relative and absolute humidity data (Figure 13 and Figure 14) indicate high humidity levels in summer and lower levels in winter. Although temperature and humidity in summer could support the growth of vegetation and mold, the strong wind and intense solar radiation help maintain wall surface dryness and inhibit biological erosion. At point N8, despite similar wind speeds to N10, the dense tree coverage reduces solar exposure, resulting in wall bulging and fungal degradation. Spot N9, with consistently low wind speed, additional shielding from wind and rain by trees, and its location at a building corner, is especially prone to cracking, fungal and mold growth, and plant-induced deterioration. Spots N10 and N11 receive sufficient sunlight in summer, but due to falling roof tiles and insufficient rain protection, they experience surface erosion and plaster detachment. Spot N12 is relatively well-lit and exposed to higher wind speeds; while some detachment of blue stone and rammed earth at the corners has been observed, the damage is less pronounced. Spot N13, located downwind in both summer and winter, has lower wind speeds and higher humidity, leading to mold formation and fracturing or peeling of the wall surface.

Among the inner spots, visual parameters (Figure 5) show that only the lower patio experiences relatively higher wind speeds year-round. The northwest corner of the lower patio, however, maintains lower wind speeds. Other interior points and surrounding walls and corners have low wind flow and constant humidity, creating conditions conducive to mold development. Despite the generally weak overall wind conditions, seasonal wind direction and localized wind flow variations in the GEH are critical to environmental performance. Effective ventilation plays a key role in suppressing mold and vegetation growth. Specific design strategies include maximizing southeast-facing window openings and employing operable louvered or casement windows to capture prevailing summer breezes, and integrating vegetative shading and extended eaves at southeast corners (N13 and N14) to balance solar protection with ventilation. At the southeastern corners of nodes N1, N13, and N14, due to low wind speeds (<1.5 m/s) and winter temperatures ranging between 8 and 15 °C in the northeastern corner, the conditions are favorable for weed growth and microbial proliferation. Therefore, biological protection measures are recommended for these spots, such as maintaining patio depths within 2.8–3.0 m to optimize wind airflow efficiency; enhancing upper and middle patio layers with high WWR and movable partitions to increase air circulation; and prioritizing square courtyard configurations to balance lighting and ventilation. In moisture prone areas such as N9 and E8, lime-based wall coatings on rammed earth as traditional material is recommended. Raising the height of the rear eaves to incorporate tiered skylights can also improve ventilation and lighting in the central hall and flanking rooms.

To address the adverse effects of high humidity, several passive strategies are proposed. High windows in rear and side rooms can induce stack ventilation, reducing moisture accumulation while maintaining insulation by limiting the WWR on sun-facing walls. The application of vapor-permeable lime coatings and dense materials such as rammed earth can effectively delay moisture ingress. Given the diurnal humidity fluctuation patterns, special attention should be paid to increasing ventilation during peak humidity periods such as early morning and evening.

7.2. Passive Survivability

According to subjective human thermal comfort zone standards, the acceptable humidity range is 30–70% RH at a Standard Effective Temperature (SET) of 25.2 °C [81]. At 80% humidity, a tolerable temperature is 30.3 °C, while at 90% RH, it rises to 32.3 °C. Simulated visual data (Figure 14a) show that temperatures within the GEH range from 5 °C to 38 °C, with only occasional readings between 0 °C and 5 °C. Relative humidity typically stays between 30% and 80%, with brief intervals dipping to 20–30% RH or rising to 80–90% RH. Absolute humidity mostly falls within 0.005 kgw/kga to 0.02 kgw/kga, with some occurrences at 0.00–0.005 kgw/kga and 0.02–0.025 kgw/kga. Overall, these values fall within the general thresholds for human thermal comfort.

From the perspective of passive survivability, the analysis of the GEH with regard to thermal comfort [53] shows that optimal comfort levels are generally achieved at 18–25 °C in summer and 20–27 °C in winter [82]. In China, comfortable wind speeds are defined as below 2 m/s in winter and below 5 m/s in summer [80], with the most comfortable ranges between 0.5 and 3 m/s and 30 and 60% RH [29,53,56,83].

The visual diagram of simulated thermal comfort duration (Figure 12) suggests that spot N5 experiences longer periods of high temperature than N6. However, on-site investigations and empirical data indicate that despite the visual data representation, the patio adjacent to N5 is deeper than that of N6. Measurements reveal that N5 receives slightly less solar radiation and maintains a lower temperature than N6. Particularly, as illustrated in Figure 6, the small patio near N5 and N6 generates stronger wind than N6, creating a cooling corridor effect during the summer months. Conversely, in winter, when the prevailing wind comes from the northwest, N6 experiences stronger wind. Given the higher summer temperature and lower winter temperature, it is evident that N5 consistently provides better thermal comfort than N6 across all seasons. As shown in Figure 6, N5 is cooler than N6 in both summer and winter. The solar radiation density (Figure 8) shows that N5 receives slightly less radiation than N6, both ranging from 392 kWh/m² to 789 kWh/m².

The adjacent patio of the lateral rooms ranges from 2.8 m to 3.8 m in length. In summer, compact, square-shaped patios exhibit lower temperature variations, remain cooler, and are more thermally comfortable compared to elongated patios. However, they tend to have weaker natural light and reduced ventilation, resulting in constant humidity levels. Therefore, a square patio of approximately 2.8 m is more favorable for maintaining thermal stability and seasonal energy efficiency. Nevertheless, enhancements such as increased daylight access and the addition of small air inlets at lower levels are recommended to promote upward hot air movement and improve overall comfort.

To address interior spots’ illumination issues, it is recommended to increase the WWR and install operable louvered doors, allowing the flexible adjustment of solar shading and daylighting across summer and winter seasons. At the Huatai mound, wind speeds were significantly higher at spots N4, N15, and N16. Among them, N15 and N16 experienced stronger winds in summer and milder conditions in winter, while N4 exhibited intermediate characteristics. These findings suggest that, under a consistent building orientation, curved enclosure forms demonstrate better adaptability to local wind patterns and airflow variations than linear configurations. The orientation and wall enclosure methods of the building appear well aligned with the local topography and prevailing wind directions. Annual temperature variations are relatively minor, with the most notable changes occurring in December and January, when temperatures drop and humidity remains moderate.

The solar radiation ranges widely from 588 kWh/m² to 1179 kWh/m². Notably, N16 records higher irradiance levels compared to N14 and N15. This implies that, assuming a constant building height, orientation, and materials, the northeast-facing envelope of the residence receives more solar radiation during winter than the southeast-facing side. Thus, reducing the WWR on the northeast façade can help lower both solar gain and glare during colder months. Conversely, increasing the WWR on the southeast façade, complemented with flexible shading strategies, can enhance daylight penetration in winter while limiting direct sunlight in summer.

For flooring materials, traditional cobblestones or fragmented stone surfaces are recommended over smooth, glossy concrete to mitigate glare. The “sunlit ground” zones are characterized by high solar radiation and wind, making them ideal for increasing the height of lower or lateral rooms. This adjustment can reduce glare and improve the utilization of dominant summer winds. The implementation of flexible door systems also contributes to heat retention during winter. Accordingly, increasing the depth of lower halls, along with wider roof spans and eaves, is advisable to reduce glare and enhance climate responsiveness.

An analysis of the human comfort zone in the GEH indicates that the region experiences high temperatures along with elevated humidity, particularly in spring and summer. Under these conditions, buildings require enhanced wind ventilation and heat dissipation. Therefore, the lower hall and the lateral rooms near the main entrance should adopt passive climate-responsive strategies. For example, the walls facing the sunlit zones should have a reduced WWR to mitigate summer glare and enhance winter thermal retention, while the walls facing the courtyard should adopt a higher WWR to maximize natural lighting and ventilation, thereby reducing the risk of dampness and mold growth.

Based on the literature review and on-site observations, and in consideration of humidity-related physical phenomena, the use of high-density, low-porosity materials, and thus continued use of rammed earth and adobe material, is recommended, as these materials can slow down thermal transfer, stabilize indoor temperatures, and exhibit higher thermal resistance, thereby improving insulation performance.

With regard to patio spaces, they receive moderate levels of solar radiation and benefit from good wind circulation. In summer, southeastern winds are prevalent, while winter winds are generally weaker. In terms of thermal comfort, ambient temperatures range from 12 °C to 38 °C, with daytime summer temperatures averaging between 22 °C and 39 °C. During this period, elevated humidity levels increase thermal discomfort. Thus, enhancing airflow during summer can effectively lower both air temperature and humidity, thereby improving thermal comfort.

An increased WWR contributes to spatial openness and facilitates better wind as cross-ventilation. Shallower lower halls are more compatible with the climatic conditions of Meizhou, as they reduce solar radiation density without impeding wind airflow, thereby providing a comfortable indoor environment throughout both winter and summer. In contrast, upper halls and lateral rooms adjacent to Huatai mound experience reduced air movement but increased solar exposure. From March to October, temperatures in these areas fluctuate between 24 °C and 38 °C, with prolonged dew formation periods in the early mornings and evenings, typically around 25 °C. Therefore, these zones are better suited to the implementation of wide eaves and adaptable architectural solutions to accommodate a higher WWR and wide eaves while ensuring thermal and visual comfort.

8. Conclusions

This study investigates the Guangludi Hakka enclosed dwelling in Meizhou, a representative three-hall enclosed dragon house, focusing on two core factors of building climate adaptability: longevity and passive survivability. By integrating on-site measurements, meteorological data, parametric environmental modeling, and human comfort assessments, it develops a climate adaptability visualization and optimization framework applicable to traditional architecture in subtropical regions. This research presents a comprehensive evaluation of Hakka enclosed house climate adaptability under subtropical conditions (Table 3, Table 4, Table 5). Combining parametric simulations (Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11 and Figure 12) with empirical field measurements (Figure 13, Figure 14, Figure 15, Figure 16 and Figure 17), this study provides in-depth insights into the microclimatic interactions between the Hakka house and its environment (Table 3, Figure 18 and Figure 19).

This study provides innovation and contributions mainly in three aspects:

(1)

Dual-dimensional evaluation of longevity and passive survivability under subtropical conditions. Existing studies on Hakka dwellings in hot–humid climates have largely concentrated on isolated factors such as wind, thermal, humidity, and illuminance, without integrating comprehensive digital modeling and on-site validation. The literature also lacks robust mechanisms for comparing simulation outputs with empirical measurements, and assessment methods for longevity and passive survivability remain underdeveloped. This study is the first to introduce a dual-dimensional evaluation pathway for subtropical Hakka enclosed houses, enabling the quantitative identification of vulnerable architectural zones and the assessment of human comfort under naturally ventilated, non-mechanical conditions.

(2)

Integrated methodological approach with empirical validation. A high-resolution digital model was constructed using Rhino + Grasshopper, embedded with the Eddy3D (wind environment), Ladybug (thermal–humidity analysis), and Honeybee (daylighting/energy performance) plugins, enabling climate adaptability simulations across 41 measurement spots (16 interior spots, 13 exterior wall spots, and 12 rooftop spots). The simulations incorporated EnergyPlus EPW climate datasets, CBE thermal comfort standards, and the Chinese Standard for assessment of green building [60,61,84], achieving cross-scale, multi-criteria, all-weather analysis. On-site measurements were conducted on 21 June and 29 December 2024 across four representative time periods per day, generating over 300 datasets of temperature, humidity, wind speed, and illuminance, supplemented by subjective comfort assessments from 10 participants.

(3)

Assessment of findings for building adaptability. Regarding longevity, the dwelling suffers from localized deterioration primarily due to weak wind exposure, wind-driven rain, and insufficient solar radiation at specific locations (notably E8–E10 and N1–N16), as identified through a literature review and on-site observation (Figure 16). These climatic factors contribute to wall erosion, fungal growth, roof deterioration, and material decay. Interior zones between lateral rooms and the central hall exhibit inadequate daylighting and humidity accumulation, undermining both comfort (Table 5, Figure 19) and structural durability (Figure 4). Field surveys indicate that the most severe erosion occurs on exterior walls below 2.8 m (E6, E9, and E10), particularly in shaded areas adjacent to Fengshui groves or newly constructed buildings, where lime surface detachment, bulging, and mold proliferation are evident. Rooftop points H6, H7, and H10 record solar radiation intensities of 1760–1960 kWh/m², correlating with advanced material degradation. Wind speed simulations reveal that inner courtyard zones N5–N12 maintain wind speeds below 0.3 m/s year-round, creating ventilation dead zones conducive to moisture accumulation and biological weathering.

Regarding passive survivability, the findings demonstrate that the Guangludi dwelling exhibits strong thermal buffering and structural resilience. The thermal comfort percentage analysis shows that south-facing courtyards such as N1, N13, and N14 achieve up to an 80% comfort duration in March–April and October–December. During summer midday periods, indoor air temperatures remain approximately 5 °C lower than outdoors, indicating effective heat attenuation. Indoor absolute humidity in summer ranges from 0.010 to 0.014 kgw/kga, representing a 12% reduction compared with outdoor levels. Illuminance measurements range from 72,000 lux at N9 to 125,000 lux at E12, while winter nighttime indoor illuminance often falls below 2 lux.

Additionally, a comparison of simulated and measured data shows a mean wind speed deviation of approximately ±0.25 m/s and an illuminance deviation within ±8000 lux. Field measurements confirm that obstructions such as newly added eaves (E5 and E6) and Fengshui groves (E8 and E9) significantly influence ventilation patterns, highlighting the necessity of accounting for actual terrain and adjacent structures in simulation models.

This study also conducted design implications and adaptive strategies. Quantitative analysis of wind speed, solar radiation/illuminance, humidity, and thermal comfort percentages confirms that key spatial parameters—patio depth, eave height, hall width, and window-to-wall ratio—directly affect climate adaptability. Parametric simulations validated by field data support targeted interventions, including enhancing ventilation through adjustable partitions and vertical shafts, optimizing patio dimensions and fenestration design, and applying protective surface treatments to erosion-prone areas. Retaining traditional spatial features, such as the Fengshui pond and courtyard layout, further contributes to thermal regulation and environmental resilience.

9. Limitations and Future Outlook

This study combines on-site investigations, parametric model simulation, and visual parameters to assess and demonstrate the climatic performance and rationality of this traditional residential typology. It proposes subtropical climate adaptation strategies based on longevity and passive survivability for Meizhou’s Hakka enclosed dwellings. These findings provide a data-driven foundation for the protection, renovation, and future design of new Hakka residences, offering both theoretical insights and practical value.

The methodological framework presented herein holds potential for broader applications in residential comfort studies, urban regeneration, and rural revitalization. By integrating computational modeling with parameterized evaluation, this study achieves both logical consistency and visual clarity in assessing two critical factors of architectural adaptability: longevity and passive survivability.

However, the current study does not yet comprehensively address subjective psychological factors such as artificial lighting and acoustic comfort. Future research will expand the applicability, feasibility, and practical implications of these methods across diverse residential types and environmental contexts. Further efforts will focus on optimizing algorithms, tools, and assessment techniques; refining parametric models; and integrating terrain-specific data to improve the precision of evaluation and adaptive strategy development. These advancements aim to support the scientific preservation and adaptive development of regional vernacular dwellings, thereby enhancing rural residential dwellings’ quality and contributing to the sustainability of cultural life in the subtropic countryside.