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In part 1, a literature review was done to summarise and introduce the theoretical background knowledge of thermal comfort and passive cooling technology. The adaptive thermal comfort was explained because it is applicable to a free-running building which is the studied object of this research. The basic theory and design standards of adaptive thermal comfort were reviewed. A brief overview of passive cooling techniques was given. The techniques were then reviewed based on their relationships with urban morphology, building shape, layout, opening and “elements”. The study started with a Chinese vernacular building (chapter 4) because these always use the passive way to achieve a comfortable living environment under the limitations of technology at that time. Firstly, the spatial design strategies for passive cooling of a Chinese vernacular house were investigated in a field survey. The design of modern rural houses under free-running conditions compared with the Chinese vernacular house. It was found that the modern rural house did not achieve a satisfactory thermal summer environment under free-running conditions, while the vernacular house did. Furthermore, the vernacular house was deeply analysed by field measurements and dynamic thermal simulations. It was found that the particular spatial design of the vernacular house has its own building microclimate, which is important for the occupants’ thermal summer comfort. The concept of building microclimate was identified. In this study, the scale of “building microclimate” refers to a type of microclimate, involving the indoor space and the spaces around the indoor spaces of a particular building. It is the extension of the indoor climate. The spatial scale is smaller than the urban fabric. It rarely covers an area more than several hundred meters wide, but is bigger than an indoor space alone. It is limited to one particular building, whether a small house or a big stadium. The building microclimate is mainly defined by the spatial and the thermo-physical properties. Similar to the influence of urban morphology on urban microclimate, the spatial configuration influences the building microclimate significantly. To have a particular microclimate at the building scale, some key factors of spatial configuration such as spatial diversity, spatial arrangement and boundary conditions between spaces should be identified. The spatial design of modern house is different from the vernacular house due to the evolution of people’s lifestyle over a long period. Can a modern house have a good building microclimate? To answer this question, the spatial design and thermal environment of a modern house were analysed through field survey and simulation. It was found that a modern house can also have its own microclimate and that the microclimate of this particular building can provide considerable thermal comfort for the occupants in summer under local climate conditions. Adaptive actions, for example movement, can explain why occupants can achieve thermal comfort in a building microclimate with diverse spaces. To find the relationship between the occupants’ spatial perception and thermal perception, a questionnaire was put forward. It was found that the spatial openness of a particular space significantly affects the occupants’ visual perception, wind speed perception and thermal perception. It was revealed that the occupants’ spatial perception and thermal perception are associated. The strongest correlation is between spatial openness and visual perception and wind speed perception. That means spatial boundary conditions can strongly influence occupants’ comfort perception, and subsequently influence the occupants’ spatial choice and movement in a particular thermal environment, given the opportunity, as Humphreys (1997) pointed out: when people are free to choose their location, it helps if there is plenty of thermal variety, giving them the opportunity to choose the places they like. The fundamental assumption of the adaptive approach is expressed by the adaptive principle: “if a change occurs such as to produce discomfort, people react in ways which tend to restore their comfort”. Nicol et al. (2012) proposed that there are at least five basic types of adaptive actions. One important adaptive action is selecting a different thermal environment. Occupant movement in a particular building microclimate is significant for thermal comfort. Occupants can change their location for different activities. Movement is possible between buildings, between rooms, around rooms, out of the sun and into the breeze, and so on (Nicol et al., 2012).

Vernacular buildings are local buildings that have evolved overtime in one location to suit the local climate, culture and economy (Meir & Roaf, 2003). The construction of vernacular buildings uses locally available resources to address local needs. These kinds of structures evolve over time to reflect the environmental, cultural and historical context in which they exist (Coch, 1998). The building knowledge of this type of architecture is always handed down traditions and is thus more based on the knowledge achieved by trial and error and in this way handed down through the generations (Singh et al., 2009). Vernacular buildings are most often residential buildings. People have traditional lifestyles in vernacular buildings in virtually every climate in the world, from the Arctic circle to the tropics, in temperatures from below zero to over 40°C, and historically without the benefit of gas or electrically driven mechanized heating and cooling systems (Meir & Roaf, 2003). After the emergence of modernist architecture, aided by the industrial revolution, vernacular buildings are seen to be in a state of decline and are frequently looked down upon, abandoned, neglected or actively demolished. Associated, by many at least, with an out-dated past and poverty, they are steadily replaced by architectural models that favour more modern, inter-national technologies, materials and forms (Oliver, 1997). It is assumed, as in international standards such as CENASO 7730 or ASHRAE 55, that people suffer less discomfort in very closely controlled conditions, then such vernacular buildings, along with modern passive buildings, cannot provide their occupants with ‘comfortable’ indoor climates (Santamouris, 2007). But nowadays, by the more and more important issues of energy consumption in building construction sectors, the continuity of the vernacular traditions is emphasized in academic research and building practice because of its climate-response, passive model and low-energy consumption. The principles that were used in traditional buildings can very well be implemented in modern buildings so as to produce “energy saving” buildings. If these principles are sensibly adopted in modern buildings, it should be possible to build sustainable buildings for the future (Shanthi Priya, Sundarraja, Radhakrishnan, & Vijayalakshmi, 2012). We can learn a lesson from the approach of the builders who acknowledged the interdependence of human beings, buildings and physical environment (Coch, 1998). A “new vernacular” can be developed, harnessing the types of low-tech solutions that are familiar to most of us from the vernacular, together with modern passive and active renewable energy technologies and strategies to reflect the new cultural, climatic and economic realities of the 21st century (Meir & Roaf, 2003). Vernacular buildings have to adapt to the environment through low-tech methods. Changing building form and material is the most important technique to adapt to the environment to obtain the best comfortable living space, in another words, the environment deeply influenced building form design and material use. Fathy (1986) described the climate effect on building form generation in vernacular building as: “For example, the proportion of window to wall area becomes less as one moves toward the equator. In warm areas, people shun the glare and heat of the sun, as demonstrated by the decreasing size of the windows. In the subtropical and tropical zones, more distinctive changes in architectural form occur to meet the problems caused by excessive heat. In Egypt, Iraq, India, and Pakijstan, deep loggias, projecting balconies, and overhangs casting long shadows on the walls of buildings are found. Wooden or marble lattices fill large openings to subdue the glare of the sun while permitting the breeze to pass through. Such arrangements characterize the architecture of hot zones, and evoke comfort as well as aesthetic satisfaction with the visible endeavour of man to protect himself against the excessive heat”. In recent years, a significant amount of research has looked specifically at environmental performance issues of vernacular architecture, including its thermal properties, energy consumption and resources (Foruzanmehr & Vellinga, 2011). Both qualitative and quantitative such as field measurements, field surveys, statistical methods, comparative study and computer simulation methods are used in the investigation of the performance of vernacular buildings. Professor Paul Oliver of Oxford University compiled the book “Dwellings: Encyclopedia of Vernacular Architecture” and published in 1997 with 4000 pages collection of research by over 750 authors from 80 countries. With two volumes categorized by climate and the ‘‘vernacular responses’’ of a plethora of cultures and another volume focused on materials, resources and production, it is the world’s foremost source for research in the area (Zhai & Previtali, 2010). Zhai and Previtali (2010) introduced an approach to categorizing distinct vernacular regions and evaluate energy performance of ancient vernacular homes as well as identify optimal constructions using vernacular building techniques. Chandel, Sharma, and Marwah (2016) reviewed the vernacular architecture features affecting indoor thermal comfort conditions and energy efficiency for adaptation in modern architecture to suit present day lifestyles. Singh et al. (2009) carried out a qualitative analysis on the vernacular buildings in north-east India. And Shanthi Priya et al. (2012) have conducted the qualitative and quantitative analysis to investigate the indoor environmental condition of a vernacular residential building in coastal region of Nagapatinam, India. Cardinale, Rospi, and Stefanizzi (2013) performed one experimental research on two types of vernacular buildings which lie in Southern Italy. Nguyen, Tran, Tran, and Reiter (2011) carried out an investigation on climate responsive design strategies of vernacular housing in Vietnam by a new research methodology which is adapted to the natural and social context of Vietnam. Ng and Lin (2012) analysed the microclimate of two Minangkabau vernacular houses in villages of Balimbing of Bukittinggi, Sumatra, Indonesia. Ali-Toudert, Djenane, Bensalem, and Mayer (2005) addressed the issue of outdoor thermal comfort in a hot and dry climate in relation to urban geometry. Beccali, Strazzeri, Germanà, Melluso, and Galatioto (2017) reviewed some models evaluating thermal comfort in natural ventilated vernacular buildings, based on adaptive approaches. Borong et al. (2004) concluded that sun shading and insulation are of great importance while natural ventilation is just considered as an auxiliary approach for the design principles of the traditional Chinese vernacular dwellings, based on the field measurements of the thermal environment parameters and a long-term auto-recorder of the indoor and outdoor temperature at four typical traditional vernacular dwellings at Wannan area in summer. Bouillot (2008) studied six Chinese vernacular houses in different provinces and found that the value and the diversity of the Chinese housing stock is due to the combination of the specific structure of the Chinese eastern climates, which creates the contrast of cold-dry winters and hothumid summers, with the structure of the Ming t’ang, which contains the opposition of the yin and the yang. Liu et al. (2011)’s study interprets the characteristic of warm in winter and cool in summer in traditional Yaodong dwelling by measuring the indoor, outdoor and the wall’s temperatures in winter and summer. The results show that the Yaodong thick wall effectively damps the external temperature wave and keeps a steady inner surface temperature, are the chief causes of warm in winter and cool in summer in Yaodong. Gou et al. (2015) focused on a qualitative analysis of ancient dwellings located in the village of Xinye, in the hot summer and cold winter region of China. According to the analysis, the climate responsive strategies of the dwellings are mainly focused on natural ventilation, sun-shading and thermal insulation, illustrated by different building aspects such as the building location, building group layout and orientation, internal space arrangement, opening design, among other variables. Soflaei, Shokouhian, and Zhu (2017) investigated the potential of traditional courtyard houses in Iran and China in responding to environmental challenges alongside social norms over a long period of time. The social and environmental dimensions of the sustainability as well as the main elements of traditional courtyard houses in Iran and China were identified. Because of the advantage of vernacular building using passive ways to achieve thermal comfort and energy efficiency as mentioned above, this research will start with the investigation of a Chinese vernacular buildings in chapter 4. The next part of the literature review is an overview of passive cooling techniques.

The basic theory of space syntax was described in section 2 of chapter 9. Some methods have been developed from the theory of spatial analysis to explore the spatial structure of buildings and cities. The DepthmapX-one graph-based representations and measures program (Turner, 2001) is one of the most important platforms for space syntax analysis. Convex and axial analysis, isovist and VGA analysis, as well as segment analysis are the methods involved in this programme (Al_Sayed, Turner, Hillier, Iida, & Penn, 2014). The axial and segment analysis are more suitable for the analysis at the urban scale. The convex analysis is suitable for the building scale and isovist and VGA analysis are suitable for both urban and building scale. Many cases have been studied to reveal the topological relationship between the spaces which is related to the social behaviour of human in building or urban scale via DepthmapX. In this chapter, the traditional space syntax methods for building spatial analysis used in the Depthmap were discussed firstly. Then, the author shows how to extended the traditional methods for natural ventilation potential analysis.

The main objective of this dissertation is to find the main factors of building spatial configuration that affecting the thermal summer environment, the possibility of occupants to achieve thermal comfort there in, and to propose a spatial design method as the passive cooling strategy for summer thermal comfort. In accordance with the objective, the research questions were put forward in section 1.5 of chapter 1. For every sub-question, there is a respective chapter to answer it, see figure 1.3 in section 1.6 of chapter 1. In chapter 8, some conclusions of part I of this dissertation were summarised. In this chapter, the research questions are answered. In addition, the limitation of this research and recommendations for future practice and research will be mentioned as well.

In the early design stages, architects are in constant search of a design direction that can determine the success or failure of the final design. However, in real design practice, most of the prediction methods for building performances, in this paper energy and thermal comfort, are utilised in the later design stages. Spatial configuration is one of the most important issues for architectural design in the early design stage. This study investigates the correlations between the spatial indicators connected with architectural design and the building physics indicators ventilation performance and energy performance. The main objective is to explore the potential of applying spatial indicators using space syntax to predict ventilation performance and energy performance in order to support architects for the evaluation of their concept and schemes in early design stage. The layout of a high-rise apartment in China in five different cities is chosen as a case study. The results show that the selected three indicators: connectivity value, air change rate and annual cooling saving ratio are linearly correlated, not just at building level but also at room level. R2, the correlation coefficient of determination, is between 0.53 and 0.90 (except for the case of Chongqing at building level).

In chapter 9, it was found that the spatial indicators can reflect the airflow performance. There is a positive or linear correlation between the spatial indicators (connectivity, integration and depth) and the airflow indicator (airflow rate). The indicators that reflect the accessibility of the spatial configuration, i.e. connectivity, integration and depth, reflect the potential of achieving natural ventilation of a particular spatial configuration. In the other words, a high degree of connectivity, integration and low depth value mean a high accessibility of the spatial configuration and a high potential of obtaining natural ventilation. This result is useful for the architectural design practice, especially in the early design stage. In chapter 10, the extended space syntax methods in the program of Depthmap for natural ventilation potential analysis were proposed by the author. In this chapter 11, the proposed methods for spatial analysis will be used for design practice. The spatial configurations of a number of Chinese rural house designs in the area studied will be evaluated in terms of natural ventilation potential for thermal summer comfort by the proposed spatial analysis methods. The rural houses as a case study in this research is chosen because the Chinese rural houses normally using passive ways to achieve thermal comfort in summer, therefore the spatial configuration for natural ventilation is important, as the author concluded in part 1 in this thesis. In addition, the rural population in China accounts for 40% of the total population with a total amount of approximately 560 million at the end of 2018 (NBSC, 2018). At the end of 2014, there were more than 585,451 villages in China and the rural housing area is at present 22.6 billion m², within a total area of more than 40 billion m² of China’s urban and rural housing together. The amount of rural housing is constantly rising. According to 2010 data, the total floor space of newly built houses is 1.6 billion m², and half of them are rural residential buildings (NBSC, 2018). Therefore, improving the living environment for Chinese rural residential buildings is important for the sustainable development of China. Moreover, previous studies have been carried out on the sustainable development of Chinese rural residential building. However, many investigations and studies related to energy conservation and indoor thermal comfort have been proposed for northern China’s rural houses (Jin & Zhou, 2008; Lai, Zhang, Wei, & Zhang, 2011; Sun, 2003; Yang, Yang, Yan, & Liu, 2011; Zhao & Jin, 2007; Zheng, Li, & Yang, 2008), focusing on winter comfort. Studies of the Chinese rural residential building in the hot humid climate regions are scarce (Han, Zhang, & Zhou, 2009; Jin, Meng, Zhao, Zhang, & Chen, 2013; Liu, Tan, Chen, Chu, & Zhang, 2013; Xie & Shi, 2012). Studies of spatial configuration for passive cooling of rural residential building design are very scarce.

In chapter 11, the VGA analysis method proposed by the author was used for the evaluation of the layout designs of Chinese rural houses proposed by the local government. Type 10 was selected as best design type, because it can most easily achieve thermal summer comfort for occupants in passive ways. The optimised layout has a high potential to achieve natural cross-ventilation, especially in the public spaces, which are important for the local occupants’ thermal summer comfort in hot and humid climates. Chapter 11 also shows occupants’ movement behaviour in the spaces. The public spaces in the house are the most attractive spaces for occupants. This is related to the occupants’ spatial perception. This helps the occupants to enjoy the natural ventilation in the public spaces because there is a high potential to achieve natural ventilation there. In this chapter, the optimised layout design of chapter 11 will be developed for a new rural house design in the studied area. The focus of the design is still on the occupants’ behaviour and natural ventilation potential with respect to the spatial configuration. This study will demonstrate how to use the VGA analysis method for the optimisation of spatial configuration, coupling occupants’ behaviour and natural ventilation analysis to design practice.

In our current age, sustainability is a key issue in the development of society, economy and environment. It is widely discussed that it is necessary to achieve a balance between the needs of people, business and nature. To maintain and possibly improve the built-up world in an ecological sense is a worldwide challenge for the current and next generation of architects, designers, technicians, public servants and decisionmakers on every level (Kristinsson, 2012). Health nature and human delight are important factors in creating new manmade living environment-city, neighbourhood and building-but these form no common basis for design. The building sector plays a significant role in the overall energy consumption, consuming over one-third of the global final energy consumption. Most of the energy is for the provision of lighting, heating, cooling and air conditioning. As human society develops, the energy demand of buildings could continuously increase globally. Therefore, reducing the energy consumption in the building sector is an important research topic. After decades of effort, to improve the efficiency of energy systems and to develop clean and new energy, architects, engineers and researchers have also tried to develop passive ways to reduce the energy consumption of buildings and to provide a comfortable living environment for occupants. More attention is paid to vernacular buildings in order to get inspiration for passive cooling and heating techniques. Passive cooling for thermal comfort in summer is a big issue for low-energy building design, and has received more attention from designers and researchers in recent years. An important reason is global and local climate change, which increases the ambient temperature and the corresponding number of cooling degree days. In addition, because of the developing economy, improvement of people’s living standards, and globalisation of modernist architecture1, the energy needs of buildings have increased rapidly. In particular, cooling the building is challenge, especially in countries where few resources are available. Passive cooling techniques are based on the application of solar and heating control systems, dissipation of the excess heat into low-temperature natural sinks and the amortisation of the heat surplus through the use of additional thermal mass in the buildings (Santamouris & Asimakopoulos, 1996). The passive mode for cooling of buildings largely depends on the design of urban and building forms. Designers have proposed many passive design strategies to improve the thermal environment for summer comfort. Urban morphology, building form (shape) and building components are normally the focuses in these studies. However, the significance of building spatial configuration for passive cooling and occupants’ thermal comfort in summer has not been studied sufficiently. Space is the empty part of the building, but its volume is important for the activities of occupants. It is the volume that people live in with various physical and psychological sensations. In his Taoist classics “Tao Te Ching”, the great Chinese thinker, Lao Tzu (571 BC - 471 BC) described building space as: “By cutting out the doors and windows we built a house and on that which is non-existent (on the empty space within) depends the house’s utility”. An architect usually thinks and designs in squares and cubic metres, lines, areas, volumes, luminance differences (Kristinsson, 2012). Architects define the general spatial structures of buildings mainly in the early design stages, and the spatial properties, the connection of the spaces and the boundary conditions of them are significant for the building performance and thermal sensation of occupants. What is the contribution of spatial design for passive cooling? Can we achieve more a comfortable living environment through the adjustment of the spatial configuration? In this dissertation, the objects studied for passive cooling will be spatially configured instead of the urban morphology, building form (shape) and building component. The relationship between spatial configuration and thermal summer comfort will be clarified and a potential design method will be proposed for the spatial analysis for passive cooling.

The authors wanted to prove that there is a large correlation between the concepts spatial openness and comfort (visual, wind speed and thermal) perception in people’s minds in a hot and humid climate in summer in order to be able to use spatial configuration parameters such as openness, connectivity and depth as a design tool for a comfortable an energy efficient building in the early design stages. 513 local Chinese college architecture students in 2015 were questioned about the relationship between spatial openness and comfort perception. The main findings for a hot and humid climate are: a. spatial openness of a particular space significantly effects occupants’ visual perception, wind speed perception and thermal perception in a particular space (p < .05). b. There is a strong effect size between spatial openness and visual and wind perception (w = .50 and .54); the effect size of the thermal perception is weaker (w = .14). c. The comfort perception is strongly influenced by the time of day, therefore visual perception, wind perception and thermal perception can influence occupant movement between different spaces as is the advice of the adaptive thermal comfort.

Passive cooling for thermal comfort in summer is a big issue in low-energy building design. An important reason is global warming because global warming increases the number of cooling degree days. In addition, the energy demand of buildings has increased rapidly due to both the improvement of living standards and the globalisation of modern architecture. And finally, cooling a building is especially a challenge in countries where few resources are available. Passive cooling techniques, where solar and heating control systems are applied, largely depend on the design of the urban morphology and the building shape. The first research question is therefore: What is the relationship between spatial configuration, thermal environment and thermal summer comfort of occupants and how to apply spatial configuration as the passive cooling strategy in architectural design? Space is the empty part of a building, but its volume is important for the activities of occupants. Architects define the general spatial structure of a building mainly in the early design stages. There they define the spatial properties of a building, i.e. how the spaces are connected and what are the boundary conditions between the spaces. The final research question of this research therefore is: What is the relationship between spatial configuration, thermal environment and thermal summer comfort and how to apply spatial configuration as passive cooling strategy in architectural design in the early stages? In order to answer this research question, this dissertation is divided into two main parts. Part I is the theoretical research phase. The goal is to clarify the relationship between spatial configuration of buildings, the thermal environment and thermal comfort of occupants in summer. In this part, a literature review of the fundamental theoretical background knowledge of thermal comfort and passive cooling technology is summarised. As the author got his inspiration from Chinese vernacular architecture, the second step was conducting surveys and performing analyses of the spatial design, thermal environment and thermal summer comfort in Chinese vernacular buildings. Contemporary residential buildings were also investigated. A challenge was to find examples of contemporary buildings with appropriate spatial designs and thermal comfort as well as contemporary buildings with less successful spatial designs and thermal comfort. The third step was to find correlations between the occupants’ spatial and thermal perception through questionnaires. Questionnaires were held among Chinese as well as Dutch architecture students. The main research outcome of part I is the definition of “building microclimate”. Building microclimate is defined as “a type of microclimate which involves indoor spaces and spaces surrounding the indoor spaces in a particular building”. It is not just the microclimate around the building; it also includes the indoor climate. A suitable building microclimate is important for the occupants’ thermal comfort in summer. Another research outcome of part I is the revelation of the relationship between spatial perception and adaptive thermal comfort. Combining the relationship between spatial perception and adaptive thermal comfort with the new definition of building microclimate leads to the conclusion that the spatial configuration of a building plays an important role in creating a particular building microclimate. Part II is a practical research phase. The goal is to explore the possibility of using a spatial design method as a passive cooling strategy for thermal summer comfort and to demonstrate how to apply this method in the early design stages. As a first step, the potential of using a space analysis method for passive cooling and thermal comfort was investigated. A convex spatial analysis method was developed from the traditional space syntax method to analyse the natural ventilation potential. Both the logical relationship between the spaces and the boundary conditions between the spaces can influence the accessibility of a particular spatial configuration, and thus influence the potential for natural ventilation. The convex space analysis method is chosen for the preliminary analysis to show the logical relationships between spaces. It cannot completely predict natural ventilation, but it is a graphical method that is easy to use. Architects conceive design solutions generally through graphic methods, making the convex space analysis a good design tool. The extended visibility graph analysis (VGA) method is the best choice for the natural ventilation potential analysis for a spatial configuration. The isovist measure can be used for the natural ventilation potential of a single space. Two case studies were performed to demonstrate the proposed method for architectural design in the early design stages. The main finding of part II is the potential of using spatial indicators to predict the airflow performance of buildings. New applications of the developed space syntax methods are proposed to help architects in designing a contemporary building that is thermally more comfortable and that has a lower energy demand for cooling. This research is performed at the cross disciplines of architectural spatial design, passive cooling and thermal comfort. This research proposes several ideas for the first time. The term “building microclimate’ is one. The application of a spatial design parameter for thermal comfort is another. This research can contribute to the sustainable development of buildings, Chinese ones in particular. It can help design residential buildings for occupants with low and medium incomes by decreasing the necessity of air conditioning and improving the living environment for thermal comfort as well. This research is also valuable for passive or zero-energy design of houses in the Netherlands and the Mediterranean area. This research will enrich the green building science by introducing enhanced space syntax methods for adaptive thermal comfort and for passive cooling by means of spatial design. This thesis is mainly composed of a collection of the author’s published papers.

In this paper, the authors attempt to clarify the relationship between spatial configuration, building microclimate and thermal comfort through the investigation of a modern house in hot and humid climate with spatial diversity. First, the spatial configuration of the house was analysed in detail. The spatial geometric features, spatial boundary conditions, and human activities in the building were categorised. Secondly, field measurements were conducted to investigate the microclimate of the house. The air temperature, relative humidity and wind velocity were monitored on typical summer days. Thirdly, a dynamic thermal simulation was performed to predict the thermal comfort performance of the building over the period of an entire summer. The simulated results were compared with the measurements, and the adaptive thermal comfort approach was used to evaluate the thermal comfort. The modern house studied was found to have a varied spatial configuration, similar to local vernacular buildings, which produces diverse thermal environments in the building. The microclimate of this specific building could provide considerable thermal comfort for the occupants in summer under the local climate conditions, although thermal comfort cannot be achieved through free-running model in the hottest days, mechanical cooling or mixed model are needed.

In this paper, the authors first clarify the definition of building microclimate in free-running buildings and the relationship with summer thermal comfort. Next, field measurements were conducted to investigate the microclimate in a Chinese traditional vernacular house. Subsequently, the results of measurements were compared with a dynamic thermal and a CFD simulation in order to determine the building microclimate and thermal comfort of the present vernacular house over the period of an entire summer. The field measurements show the present Chinese vernacular house has its own independent building microclimate in summer, which is in accordance with the main character of microclimate in terms of different distributions of solar gain, air temperature and wind velocity in different spaces. The simulation results of the vernacular house could be matched well with the field measurements. According to the simulations, at night, a comfortable temperature could be obtained throughout most of the summer period whereas in the daytime the operative temperature was higher than the comfortable temperature for one-third of the summer period. Wind velocity in the semi-outdoor and outdoor spaces however, improves the thermal comfort significantly. The thermal comfort environment can thus not only change in time but also in space. This example of the vernacular building shows that it is possible to create comfortable conditions for the inhabitants when not only the indoor climate is taken into account but the whole building microclimate as defined in this paper. This paper also shows that the simulations can predict the building microclimate.

Thermal comfort is defined as “that state of mind which expresses satisfaction with the thermal environment” (ANSI/ASHRAE, 2017). The definition of thermal comfort leaves open as to what is meant by condition of mind or satisfaction, but it correctly emphasizes that the judgment of comfort is a cognitive process involving many inputs related to physical, physiological, psychological, and other factors (Lin & Deng, 2008). People are always in an internal or external thermal environment. The human body produces heat and exchanges heat with the external environment. During normal activities these processes result in an average core body temperature of approximately 37 °C (Prek, 2005). This stable core body temperature is essential for our health and well-being. Our thermal interaction with the environment is directed towards maintaining this stability in a process called “thermoregulation” (Nicol, Humphreys, & Roaf, 2012). Thermal comfort plays an important role in the energy consumption of buildings. So, researchers spent decades to find the appropriate approaches and models which evaluate and predict thermal comfort. A literature review of the current knowledge on thermal comfort shows two different approaches for thermal comfort, each one with its potentialities and limits: the heat-balance model and the adaptive model (Doherty & Arens, 1988). The heat-balance approach is based on analysis of the heat flows in and around the body and resulted in a model based on physics and physiology. Data from climate chamber studies was used to support this model. The best wellknown heat-balance models are the predicted mean vote (PMV) (Fanger, 1970) and the standard effective temperature (SET) (Gagge, Fobelets, & Berglund, 1986). The PMV model is particularly important because it forms the basis for most national and international comfort standards. The adaptive approach is based on field surveys of people’s response to the environment, using statistical analysis and leads to an “empirical” model (Nicol et al., 2012).

The objective of this paper is to clarify the spatial design strategies used to control the microclimate of a Chinese vernacular house in summer by comparing the building with modern Chinese rural houses and presenting ideas for contemporary architectural design practice. For this goal the spatial configuration, the spatial boundary conditions, the vegetation in the space and the human activity in the space were analysed for the vernacular house and for modern rural houses. Also, field measurements were conducted to evaluate the summer thermal environment in the vernacular and a modern house. The results show that the vernacular house has a diverse spatial design and a better building microclimate, making it easier to obtain thermal comfort than the modern houses. Therefore, spatial design strategies of Chinese vernacular houses are still of great value to modern house design, especially when the free-running thermal comfort theory is applied.