© C. Yang and X. Hu, Published by EDP Sciences, 2025

1 Introduction

In high-density urban contexts, architectural design for primary schools faces intricate challenges posed by spatial, land, and environmental constraints [1]. This study shifts attention to the courtyard concept as a theoretically grounded strategy to address these issues, drawing on Peng Yigang's Architectural Space Combination Theory [2]. Using the Sino-German “New City Four Primary Schools” project as a case, the research explores how courtyards integrate three dimensions of spatial sustainability. Guided by a design rationale emphasizing spatial functionality and humanistic concerns, the project operationalizes the sustainable concepts of courtyard through four interconnected approaches: an integrated framework for holistic spatial planning and design, efficient spatial division and configuration, establishment of spatial circulation links, and consideration of sustainability issues within spatial contexts. By examining these strategies, the study reveals how the courtyard concept balances efficient land use with behavioral needs and environmental quality—key to reconciling institutional functionality with urban integration, particularly in repairing urban interfaces [3] — and further identifies three distinctive attributes that define its sustainability: micro-closed-loop nature [3], daily interactivity [1], and cultural embeddedness [4].

Building on these attributes, the study reinterprets the courtyard not merely as a formal element but as a theoretically informed solution. Rooted in spatial combination theory, such layouts foster a delicate equilibrium: sustainable land use, social inclusivity, and ecological resilience. The resulting new framework distills applicable principles for urban primary school design, enriching both the practical application of Peng's theory [2] and strategies for creating context-responsive, sustainable educational architecture in dense urban settings.

2 Literature review and conceptual clarification

Previous relevant studies on sustainability have predominantly focused on four dimensions: environmental, social, economic, and cultural [4]. For example: Liang Sicheng argued that the courtyard is the ultimate space for the Chinese people to settle their lives and spirits, carrying the family ethical order and the life experience of integration with nature [5]. Al Haddad et al. examined the effects of variables such as orientation, size, and building layout across four courtyard shapes in building clusters, focusing on their impacts on shading and sunlight exposure of building facades and ground surfaces at different times during winter and summer. The study's purpose is to identify optimal courtyard design strategies for enhancing thermal comfort in sustainable residential design, particularly in Mediterranean climate regions such as Jordan [6]. Gong, Y. et al., through behavioral experiments and Semantic Differential (SD) method for quantitative analysis, proposed that in high-density residential design, spatial forms such as three-dimensional public spaces and semi-open gray spaces, as well as courtyard designs like multi-level three-dimensional green courtyard systems, are important elements in biophilic design that connect humans and nature, contributing to improving the living environment quality and residents' living experience [7]. Ucer, H. B. et al. argued that courtyard layout, vegetation, and material selection play a role in mitigating the urban heat island effect, providing operable climate-adaptive strategies for modern urban courtyard design [8].

Relevant studies involving the spatial dimension are relatively few. Peng Yigang, in Architectural Space Combination Theory [2], revealed that the courtyard has dual values of spatial organization and ecological sustainability: it realizes the integration of functional zoning and ecological efficiency through passive climate regulation and intensive spatial complexity, embodying the sustainable wisdom of “low-tech but high-intelligence” in traditional architecture. González-Redondo, E. argues that the spatial reorganization of courtyards plays a core role in achieving a balanced sustainability between cultural preservation and modern residential needs [9].

At the application level, many domestic and international architectural firms use the courtyard concept to design the spaces of primary and secondary schools, such as Tiantai Primary School, Qingdao Beizhai Primary School, Lianhua Primary School, Chengdu Tianfu No. 7 High School, Zhejiang Huzhou Southwest Primary School, Yangliu County Community Primary School, Jingyang Qingyijiang Road Primary School, Hefei Beicheng Central Park Primary School, Xiashan Primary School, France Louis de Vion School, Germany Bochum New Primary School, India Rajkumari Ratnavati Girls' School, etc. These cases collectively indicate that using the courtyard concept to respond to the design of urban primary schools has formed a design consensus to some extent [10].

2.1 The yard concept

In the book Yu Pian: ‘A courtyard is the space before the hall‘s steps,’ and ‘A yard is the enclosed area surrounded by walls 庭者, 堂前階也, 院者, 周坦也.’ [11]. The architectural histories of courtyards in China and the West are rich and diverse. The cultural legacy of ancient Greece and Rome has significantly influenced Western courtyard design, with a focus on religious function and an aesthetic blend of romanticism and pragmatism [12]. In contrast, Eastern courtyards emphasize the harmony between humans and nature, with two predominant forms: the ‘courtyard' type and the ‘corridor-enclosed courtyard' type. Both are fundamentally shaped by the traditional corridor, creating a four-sided architectural enclosure. In the evolution of modern architecture, courtyards are central spaces, encircled by multiple or separate areas [11], with a focus on the symbiotic relationship with greenery and the role of public spaces within the built environment [13].

2.2 Key characteristics of urban primary schools

The “urban primary school” concept [14], in contrast to that of a rural primary school, typically resides in peri-urban regions characterized by mature, high-density urban environments [15]. These schools cater to the compulsory education needs of urban children, aligning their operational goals, curricula, and infrastructure development closely with the evolving demands of urbanization [3]. Urban primary schools are often defined by three key characteristics: 1) They are situated in highly urbanized, economically vibrant large and medium-sized cities, such as provincial capitals and major cities in mainland China [3]; 2) They are found in cities with high population densities and limited land availability, exemplified by places like Singapore [3]; 3) Their campuses are nestled among commercial and residential zones, grappling with a multitude of constraints [14].

2.3 Sustainable design concept

Sustainable design is a design approach that emphasizes holistic planning and the judicious use of existing raw materials, technologies, capital, and resources to achieve optimal outcomes at the lowest cost without compromising ecological balance [15]. Stemming from the principle of ‘sustainable development' [14], it underscores systematic planning and an integrated design perspective [16,17]. The essence of sustainable design lies in resolving the tensions between human needs, environmental preservation, and societal progress through thoughtful design [17]. It involves striking a balance between energy consumption and regeneration, restoring the bond between humanity and nature, while fostering a symbiotic and mutually beneficial relationship for people, the environment, and resources, predicated on harmonious coexistence [18]. Within this framework, Spatial sustainable design is a design paradigm that integrates traditional spatial wisdom with modern technical methods [2]. It aims to achieve a dynamic balance between architecture and nature while meeting socio-cultural needs by optimizing spatial organization, climate adaptation strategies, and ecosystem synergy. Its core lies in using spatial form as a carrier to enhance environmental performance and user experience through hierarchical nesting, passive technologies, and ecological interface design, ultimately achieving full-life-cycle sustainability [2–9].

3 Spatial design within the framework of the courtyard concept

Chinese architect Academician Peng Yigang, in his seminal work Architectural Space Combination Theory, posits that space is the genesis of architecture [2]. He likens space to a container, whose primary function is to hold objects. The sustainable concept should entail that different objects require appropriately distinct containers. The sustainability of container space for objects should be assessed across three dimensions: 1) Sustainability of capacity: This refers to the appropriate size and capacity needed to accommodate the object. 2) Sustainability of form: Thispertains to the suitable shape that meets the object's requirements. 3) Sustainability of quality within the enclosed space: The enclosed space should provide positive and suitable conditions, such as temperature and humidity, to prevent damage or deterioration of the objects [2]. Addressing the contradictions and challenges faced in urban primary schools in practice involves tackling these three aspects of sustainability within both learning and urban spaces(see Fig. 1).

In response to the pressing spatial and functional challenges associated with urban primary schools, the “New City Four Primary Schools Project” is guided by a design rationale that emphasizes spatial functionality and humanistic concern, introducing the courtyard concept. This concept is executed through an integrated approach to holistic spatial planning and design, establishment of spatial circulation links and consideration of sustainability issues within spatial contexts. It provides a profound reflection on the understanding of space and, under the “Framework of the Three Key Points of Sustainable Container Space” by Academician Peng Yigang, from the Architectural Space Combination Theory [2], presents a new design framework for sustainable space under the courtyard concept. The overarching goal is to craft an architectural environment that nurtures student development and supports the dreams of childhood, thereby constituting an ideal organic space (see Fig. 2).

Fig. 1 Framework of the “three key points of sustainable container space” by academician. Peng Yigang (Source: Drawing in this study).

Fig. 2 “Spatial design framework diagram under the courtyard concept”. (Source: Drawing in this study).

3.1 Holistic spatial planning and design

Nanjing, as an important central city in the eastern region, according to the Statistical Bulletin on National Economic and Social Development of Nanjing City in 2023, the permanent population increased by 55,900 people, reaching a total of 9.547 million [19], facing certain land use pressures. Representative Wang Yueping also proposed: Suggestions on improving the insufficient per capita land area of famous schools in the main urban area. The “New City Four Primary Schools” project site is located in Jianye District, Hexi New City, Nanjing City, the capital of Jiangsu Province, China, and is a newly planned and constructed school, which conforms to the definition of an urban primary school.

Limiting Factors: The design of urban primary schools faces common issues, namely, numerous limiting factors, which are the compression and confrontation between urban public spaces and learning spaces. The “New City Four Primary Schools” project plans for a school scale of 6 tracks and 36 classes, with a total construction area of 28,000 square meters. In the overall site layout of spatial planning, after trying and comparing various schemes, by analyzing the surroundings of the building, it was found that in architectural design, factors such as primary and secondary road setbacks, future subway lines, and adjacent buildings need to be considered. It is necessary to maintain the relative independence and integrity of internal learning spaces to maximize the functional operation of learning spaces. The building area is ultimately determined to be 40% of the entire site area, and the site layout is selected through comprehensive consideration (as shown in Fig. 3). The enclosure and division of the courtyard effectively reconcile various surrounding restrictive factors. The new space enclosed by the building is both safe and independently free, minimizing limiting factors to the greatest extent.

Enclosure Shape: The entire building consists of 4 floors, and its bird's-eye view resembles the cultural and functional symbol of a pencil, forming an enclosed courtyard paradigm architecture. Serving as a “spatial container” for students, the building's overall space pursues a visually soft touch in its exterior appearance. The color scheme includes a ground blue plastic track, gray Qiansi aluminum panels on the exterior walls, integrated with green painted aluminum grilles and outer walls (Fig. 4), creating an enclosed large space with bright and cheerful colors.

Spirit Of The Place: The concept of the place captures the essence of a space-time unity, where the sky, the earth, and people come together to form a harmonious environment [20]. This design philosophy is rooted in the ancient Chinese concept of the unity between humanity and the cosmos 天人合一 [21]. The courtyard acts as a natural focal point, fostering a sense of cohesion with the external environment while maintaining a distinct separation. This ‘central view' design reflects the Confucian principles of order and rationality [22], thereby instilling a strong sense of spatial belonging among the occupants and promoting a robust psychological cohesion [23].

Fig. 3 Analysis of unfavorable factors for the ‘new city four primary schools’ project. (Source: Jiangsu Province Architectural D and R Institute Co., Ltd., 江苏省建筑设计研究院股份有限公司 related planning documentation).

Fig. 4 Exterior and contour drawing of the “new city four primary schools” project. (Source: Same as Fig. 3).

3.2 Efficient spatial division and configuration

The conceptual design of the courtyard diverges from the conventional design of educational spaces, presenting an informal learning environment that encourages students to learn and develop in a relaxed and liberating atmosphere. The challenge lies in optimizing the use of limited space through innovation. New City Four Primary Schools, in its internal architectural planning, incorporates the design principle of “There is separation, yet there is connection 有隔有通 [24]”, a concept articulated by Zong Baihua in his interpretation of architectural aesthetics. He elucidated that “a building is a free space that is partitioned into numerous smaller spaces and serves as a connector between these smaller spaces”. He further posited that “architecture can be considered the art of transforming free space into a series of smaller spaces and linking these spaces to create a larger one [24]”, and he also stated that “architecture can be termed the art of space [24]”. By partitioning and enclosing space to create new areas, the design achieves a blend of the tangible and the intangible [24]; concurrently, the separation of various spaces engenders distinct psychological spatial emotions, and the rational configuration of space also exerts a positive impact on social sustainability [1].

Ancient Chinese courtyards epitomize the concept of the externalization of indoor spaces and the internalization of outdoor spaces. 室內外化與室外內化 [25], where external activity spaces are enclosed within the residential compound, and internal chambers and halls are linked to the central courtyard. This configuration facilitates the interpenetration of indoor and outdoor realms, thereby achieving a harmonious blend of spatial and temporal dynamics, characterized by both static and dynamic elements [26]. The partitioning and design of formal and informal learning spaces within primary school buildings can be informed by the principle of mutual permeability [24] inherent in ancient courtyards.

The External Space Design Of Primary Schools: The design of primary school outdoor spaces has seen the significant role of playgrounds increasingly recognized throughout the history of educational development [27]. As early as 1660, the educator Charles Hooper stated that there should be a paved courtyard around the school [28]. Children can fully express their nature and “be themselves” while playing in the playground space. Primary school students, mainly aged between 6 and 13, are at a stage where they need not only to learn basic knowledge and develop good study habits but also to engage in a substantial amount of play and sports to stimulate their innate nature and gain growth and joy from play [29].

The perception of motion and repose among primary school students diverges from that of adults [30], and the dichotomy between learning and play is not always distinct. The architectural principle of movement and stillness inherent in the courtyard concept offers a solution that aligns with the unique characteristics of the primary school age group. The “New City Four Primary Schools” project employs the courtyard concept to establish a secure and autonomous urban space. A salient feature of the design is the integration of the teaching building and sports field as separate yet complementary entities within the school's layout. The strategic positioning of the running track in the northern part of the site, with a platform serving as a buffer against noise from the main street, demonstrates the design's acoustic considerations and spatial utilization. Within the atrium of the learning space, the ground pavement forms a 1-kilometer-long'super-long running track' encircling the building, traversing the courtyard to the external playground, and unifying the entire school's sports pathway (Fig. 5). This interplay of motion and stillness imbues the building with kinetic energy and fully unleashes the children's natural propensities. The building's kinetic energy is channeled through the interplay of movement and silence 動靜合一 [24], thereby fully releasing the children's innate instincts [31] (Fig. 5).

The Interior Space Design Of Primary Schools: The spatial layout of primary schools is meticulously designed to compartmentalize the interior into specialized learning and support zones. These zones include areas for teaching and ancillary educational activities, administrative offices, and various living services, as well as ground floor facilities and other designated rooms, all strategically positioned throughout the school's architecture. The deliberate spatial separation of classrooms is a critical architectural decision [3], particularly for urban primary schools striving to achieve an optimal balance between class size and student numbers within the constraints of space and resources.

In more developed nations, there is a prevailing trend towards smaller class sizes, with current averages at approximately 22.3 students in France, 27.5 in the UK, 22.7 in Germany, and 27.4 in Japan. This inclination towards compact primary school sizes is a commonality among developed countries. According to data from the Architectural Institute of Japan, the standard design for Japanese primary schools is to accommodate between 12 to 18 classes [32], with 95.8% of national primary schools operating within this range of 12 to 24 classes. Among the nearly 25,000 public primary schools in Japan, 63. 1% are situated in rural areas. The majority of these schools, specifically 63. 1%, have 24 classes or fewer, while schools with 30 or more classes are deemed oversized [33].

On average, primary schools cover an area of 15,917 square meters, with a per capita land area of 24.2 square meters per person and a per capita school building area of 11.8 square meters per person. These figures are approximately 1.5 to 2 times more generous than China's current standards [2], which specify a per capita land area of 18 square meters and a per capita school building area of 71 square meters for 24-class urban primary schools.

In contrast, China's standards often require twice the density, with an average class size of about 45 students [2]. In the ‘New City Four Primary Schools', the specified classroom dimensions are 8.5 meters by 8.4 meters, which are considered a standard size that takes into account the comfort and number of students. To ensure a certain level of spatial independence, the design for sound insulation in classrooms will draw on the experience of German primary school buildings, incorporating sound-insulating windows(see Fig. 6) to minimize noise interference and enhance the independence of learning spaces.

Fig. 5 The “new city four primary schools” project playground and track diagram. (Source: Same as Fig. 3).

Fig. 6 Master layout and spatial planning diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).

3.3 Spatial circulation links

Elementary school educational buildings encompass both formal and informal learning spaces, which are not mutually exclusive but interconnected and complementary, achieving a deep linkage of limited space. The “qi” (“气” energy) [2] within different spaces relies on traffic links to flow through, and the “permeation of qi” not only enhances the commuting efficiency of people and objects within the space but also elevates the emotional experience of the individuals within the space [2].

Spatial Access Points: In the “New City Four Primary Schools” project, the overall traffic movement design extends the inner courtyard-covered track to the southwest side, where the student entrance is located. The vehicle entrance and parking area are situated in the southeast; after dropping off students, vehicles continue forward along the guided direction to the underground parking lot beneath the classrooms. An additional entrance is located on the northeast side, near the bus station, forming a rational and safe traffic flow.

Linkage Between Formal And Informal Learning Spaces: The internal traffic flow within the courtyard is typically resolved by corridor bridges, with special classrooms and laboratories distributed along the perimeter of the building as needed. The first floor houses the main public functions, with a clear path from the school entrance to the lobby, library, multi-function hall, and canteen. Unlike the straight corridors that pass through the connecting buildings, the architectural design of “New City Four Primary Schools” introduces dynamic corridors, integrating the functions and circulation of public buildings in a circular manner. These corridors efficiently connect all core functional areas and rooms, achieving separation on the outside while ensuring connectivity on the inside (Fig. 7).

Fig. 7 Traffic flow diagram of the "new city four primary schools" project. (Source: Same as Fig. 3).

3.4 Sustainability issues within spatial contexts

Ancient Chinese courtyards are a manifestation of ecological and cultural connotations, emphasizing a layout that embodies the mutual harmony and complementarity of yin and yang 陰陽相濟 [5], advocating the unity of heaven and man 天人合一 [24], and focusing on the harmonious relationship between people and nature. sustainable building in Western contexts, a concept introduced by Kibert, C. J in 1993 [34], aims to reduce environmental load by reducing energy consumption, saving water, reducing pollution, protecting the environment, protecting ecology, protecting health, and improving productivity, integrating with the environment, and benefiting the health of inhabitants. This aligns with the architectural views of ancient Chinese courtyards.

3.4.1 Ventilation and daylighting design in green sustainability

The architectural design of the “New City Four Primary Schools” project adheres to the principles of green sustainable design, requiring a comprehensive consideration of climate, sunlight, wind, water, and landscape. Nanjing, characterized by a subtropical monsoon climate with abundant rainfall of 1200 millimeters per year, distinct seasons, an average annual temperature of 15.4 °C, and extreme temperatures ranging from 39.7 °C to −13.1 °C, experiences a spring with gentle breezes and bright sunshine; a plum rain season with continuous rain; a hot summer; a dry and cool autumn; and a cold, dry winter [35]. Located north of the Tropic of Cancer, Nanjing enjoys ample sunlight, and rational sunlight design can ensure not only the brightness of classrooms but also the suitability of temperature, reducing excessive consumption of electricity for heating and cooling. Based on the analysis of sunlight models, the optimal orientation for the buildings in the New City Four Primary Schools project is 7.5 degrees southwest. All classrooms are designed to face south, and natural light introduced by the courtyards is an effective method to improve the building's light environment, add spatial interest, and enhance the sense of spatial hierarchy [36]. Special classrooms are distributed according to spatial rationality and their individual lighting needs. The designed louvered window system prevents direct sunlight. Meanwhile, the enclosed courtyard has good thermal stability, with internal air temperature fluctuations significantly less than those caused by the microclimate of the external environment, playing a crucial role in improving the building's physical environment. The enclosed courtyard also helps to enhance the exchange of air between the interior and exterior of the building [36]. With an orderly distribution of windows, natural ventilation is ensured for all classrooms. This ensures a comfortable and stable learning environment within the building, objectively improving thermal comfort and indoor air quality (IAQ) [37], providing students with natural ventilation and good daylighting [36] (Fig. 8).

3.4.2 Sustainable rainwater recycling system

In the realm of rainwater management, ancient Chinese courtyards consciously utilized the architectural advantages of the courtyard itself. Through eaves design, water was collected in “sky wells”, also known as “Si Shui Gui Tang 四水歸堂 [38], a traditional Chinese architectural layout, particularly found in the Jiangnan region. It features a compact courtyard surrounded by buildings on four sides, with the rainwater from the roofs flowing into the central courtyard, symbolizing the gathering of wealth and harmony.)”, symbolizing the incorporation of good fortune and prosperity into the household [39]. Wen Zhenheng of the Ming Dynasty, in his Zhangwu Zhi (Records of Superfluous Things), makes reference to courtyard design: “A stone pond lies before the steps, with eaves drips channeled to fill it 階前石池, 引簷溜注之”. This explicitly indicates the practice of utilizing the eaves (eaves drips) to collect rainwater and direct it into the courtyard pond [40].

The “New City Four Primary Schools” project leverages the inherent advantages of the courtyard, combining this with Germany's rich systematic design philosophy to implement a rainwater management plan. The design takes into full consideration Nanjing's humid subtropical climate, characterized by abundant rainfall. The project utilizes rain gardens and purifying plants to absorb and retain rainwater, alleviating pressure on the drainage system and establishing wetland sites for on-site wastewater treatment. Rooftop gardens and permeable surfaces on the ground contribute to rainwater runoff management [41], and the low-maintenance water cycle constitutes a functional component of the visual landscape. This approach integrates sustainable design principles throughout the entire rainwater recycling system (Fig. 9).

Fig. 8 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).

Fig. 9 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).

3.4.3 Sustainable green energy consumption

In the realm of green energy consumption design, the “New City Four Primary Schools” project innovatively integrates a light guidance illumination system into the architecture. Along the green pathways leading to entrances and exits, the project creatively employs Power leap technology [41], which harnesses energy from the footsteps of pedestrians and converts it into electricity. This system accumulates energy from children's movements to light up the lobby, enhancing both engagement and the utilization of clean energy.

In addition to effectively harnessing solar energy, the architectural design incorporates green and clean solar thermal energy as a part of the energy supply solution. To reduce energy consumption, the designers have made effective plans for the placement of equipment, installing the solar energy system on the roof of Building Three, thereby improving the efficiency of connecting to the water heating room or generator room to supply hot water or heating [41].

The low-maintenance water cycle constitutes a functional component of the visual landscape, integrating sustainable design principles throughout the entire rainwater recycling system. This approach not only enhances the visual appeal but also emphasizes the importance of sustainable energy practices within the educational environment [41] (Fig. 10).

Fig. 10 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).

4 Discussion

Architecture involves not only science and technology, material production, and lifestyle, which are aspects of material culture, but also social politics, philosophical thought, religious consciousness, aesthetic concepts, folklore, and folk customs, which are aspects of spiritual culture. It is also a concentrated reflection of the entire life of an era and a nation [42].

Following the establishment of the People's Republic of China, architectural design concept collided and spiraled upward between Eastern and Western influences. Campus buildings inevitably bear the mark of their times, and the ‘spirit of place' within and outside the buildings reflects the design concepts and practical needs of different periods. Currently, the main forms of primary school campus architecture can be categorized into the following three types.

4.1 Regular “square box” style

Early Chinese architectural design was to some extent inspired by Soviet and modernist styles in terms of building style and spatial distribution. A large number of primary school building emerged with a regular “square box” type, characterized by a rigid, linear box shape. In building layout, these structures are typically regular and symmetrically distributed, forming building clusters with horizontal and vertical, regular “checkerboard” traffic flow patterns, generally symmetrical and repetitive. Office rooms, teaching rooms, and other functional rooms are intermixed in space. This design approach prioritizes space utilization, often suitable for a class system with more classes and larger numbers of students. Public open spaces are relatively compressed, and the actual use of teaching spaces is maximized to meet functional requirements. There are certain advantages in construction efficiency and cost (early in the construction of China's primary schools, a quota pricing model was used to strictly control costs) to meet the basic functional needs of educational spaces under the objective conditions of a large population and relatively scarce resources [3]. However, public space areas are often insufficient, and functions are relatively singular.

4.2 Organic dynamic form

In Le Corbusier's theory, the modern city should be strictly analyzed according to function [43]. He wrote in Towards a New Architecture: “The axis is the maintainer of order in architecture”. Organic dynamic forms in educational spaces have a rich sense of order along their axes, which are the core of the place. The architectural design spirit retains the Corbusier-style order and uniformity. The shapes of these buildings are often more dynamic and creative, enriching children's imaginations. The visual style of the design modeling is fresh and revolutionary, often becoming one of the local landmark architectural highlights. The spatial layout is mostly semi-open, often connected by branch-like corridors to various functional rooms, forming a clear sense of order. The advantages of this design include a clear traffic line, good lighting, and a clear distribution relationship between functional rooms. Administrative rooms are clearly organized in terms of primary and secondary, making educational management more hierarchical. The free and open direction and form can maximize benefits and avoid harm in the face of the surrounding complex environment. At the same time, the open public space area of the organic form of primary school building design is larger, meeting the needs for communication and play. In terms of space usage, the volume ratio of this kind of building design is low. The open and semi-open space form has certain requirements for the initial environment around it regarding safety, noise, and other constraints, making it unsuitable for cities where land is relatively scarce. Additionally, the construction cost of organic form buildings is high, and it needs to be balanced with local budgetary constraints.

4.3 Courtyard enclosure style

The form of courtyards in primary school architecture constructs a humanized, enclosed space within the natural environment, creating a tranquil and poetic dwelling akin to a paradise away from the hustle and bustle. As urbanization progresses and urban land becomes scarce, the (indifference, noise, stress) of the urban jungle and other unfavorable living conditions are issues often addressed in the design of primary school buildings. Facing the absence of natural elements such as 群山環抱、流水潺潺、鳥語花香 surrounded by mountains, murmuring streams, and fragrant flowers), the courtyard concept architecture, which encloses on all sides and builds around a central point, offers an independent, safe, and friendly emotional experience. It awakens the spirit of place where humans and nature coexist harmoniously, making it highly suitable for “urban-type primary schools” with complex environmental factors and tight land use.

Secondly, the objective spatial conditions of enclosure have certain advantages in social interactions. Social interactions are an essential part of human society, and primary school students typically have a fixed range of contacts, with interpersonal relationships mainly focused on parent-child, peer, and teacher-student relationships. During this stage, children require more interpersonal interactions from the school environment. Traditional teaching facility layouts have a clear sense of grade and class areas, which objectively reduce the frequency of communication between classes and grades. The centripetal design of courtyards inherently has a cohesive nature, visually capturing as much internal information of the enclosed space as possible, increasing the frequency of non-verbal communication, and forming sustainable emotions [44].

Furthermore, the “separated yet connected” enclosure form of courtyard architecture can also improve and regulate microclimates. In non-artificially intervened indoor and outdoor climate conditions, the urban external climate can increase the number of hours of indoor discomfort by 32%, while the courtyard microclimate can almost entirely mitigate the effects of urban overheating, eliminating severe indoor discomfort hours by over 88%. Additionally, in the presence of air conditioning systems, the increase in cold energy demand due to urban climate is reduced by more than 15% [45]. Naturally enhancing human comfort aligns with the design philosophy of reducing urban energy consumption.

“Urban-type primary schools” always face the dilemma of space and function. Academician Peng Yigang's Architectural Space Combination Theory [2] can provide certain design inspirations with a balanced mindset. Based on this, a new spatial sustainable design framework proposed in this paper takes spatial design as the logical starting point, infusing campus architecture design with warmth and vitality, finding a balance among urban, functional, cost, and spatial factors. Ancient Chinese courtyards contain the cosmology of the ancients, with separation and connection in space, and internal and external traffic. The courtyard concept in primary school architecture is an extracted and suitable part from the ancient courtyard living ideal, combined with modern architectural design concepts to form an integrated new approach, responding to the current educational concept reform and the dual-track development of urbanization at the design level.

5 Conclusion

The “courtyard” architectural space is an externalization of the ancient Chinese architectural aesthetic concept of “separation with connection 有 隔有 通”, a design philosophy that combines the essence of “connection” from Eastern architectural culture with the ideal of “separation” from Western architectural culture. It also interprets the interplay of the tangible and intangible, time and space, and movement and stillness. The Chinese poetic ideal of architecture emphasizes the harmony between heaven and humanity, complemented by beautiful ethics and profound education 天人合一與美人倫、厚教化, giving birth to the “courtyard paradigm” space. This paradigm not only links individuals with communities but also bridges nature with the city.

The “New City Four Primary Schools” project's sustainable concepts of courtyard design offer insights into how to better construct urban primary school spaces. The introduction of the courtyard concept into “urban-type primary school” architecture has numerous advantages. Firstly, the centripetal enclosed form of the courtyard avoids issues of urban land resource scarcity and excessive surrounding site constraints. Secondly, the free division of solid and void spaces in the courtyard forms a connected traffic flow. The centripetal linkage of spatial modules objectively increases the frequency of communication, and the existence of void spaces enriches the after-school life of primary school students and expands green areas, allowing children to be closer to nature. Additionally, due to its inherent nature and scale, the courtyard regulates its microclimate, thereby mitigating adverse climatic conditions and reducing building energy consumption.

Finally, the courtyard concept in the design of “urban primary schools” should also fully consider the local conditions, integrating the city's green energy consumption and sustainable development. It should actively blend with the city's cultural image, responding to the spirit of the city with poetic design.

Funding

Qinglan Project of Jiangsu Higher Education Institutions.

Conflicts of interest

The authors declare no conflict of interest.

Data availability statement

All data generated or analyzed during this study are included in this published article.

Author contribution statement

Xiaoyue Hu helped with the constructive discussion. Chuan Yang made great contributions to manuscript preparation. All authors read and approved the final manuscript.

References

All Figures

	Fig. 1 Framework of the “three key points of sustainable container space” by academician. Peng Yigang (Source: Drawing in this study).
In the text

	Fig. 2 “Spatial design framework diagram under the courtyard concept”. (Source: Drawing in this study).
In the text

	Fig. 3 Analysis of unfavorable factors for the ‘new city four primary schools’ project. (Source: Jiangsu Province Architectural D and R Institute Co., Ltd., 江苏省建筑设计研究院股份有限公司 related planning documentation).
In the text

	Fig. 4 Exterior and contour drawing of the “new city four primary schools” project. (Source: Same as Fig. 3).
In the text

	Fig. 5 The “new city four primary schools” project playground and track diagram. (Source: Same as Fig. 3).
In the text

	Fig. 6 Master layout and spatial planning diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).
In the text

	Fig. 7 Traffic flow diagram of the "new city four primary schools" project. (Source: Same as Fig. 3).
In the text

	Fig. 8 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).
In the text

	Fig. 9 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).
In the text

	Fig. 10 Green sustainable design diagram of the “new city four primary schools” project. (Source: Same as Fig. 3).
In the text