Investigating the role of geometry and type of urban open space on thermal comfort and environmental quality (Case study: Kashan historical part).

The availability of open spaces among buildings plays a vital role in residents’ social interactions, attendance, and security. Maintenance of the right geometrics, location, and proportionality of the surrounding environment has astounding impacts on the creation of attractive outdoor spaces for people. Neglection of the proportionality between the scale of space and surrounding buildings can lead to negative impacts on people’s perceptions and feelings of their surrounding environments. Therefore, assessment (in terms of shape and geometry) of the open spaces within the historic area of the city of Kashan, Iran can affect thermal conditions and provide senses of security and satisfaction with the environmental qualities and attributes. An evaluation was made beginning in September 2018 and lasting 18 days. 17 high-traffic spots and landmarks located in the historic area were chosen and categorized in two separate groups. These included public areas and pedestrian lanes and courtyards in the respective geometrics. The purpose was to investigate whether or not there existed a direct or indirect relationship between the specified factors and thermal comfort.

The lack of usable open spaces in cities and metropolitan areas has led to numerous issues arising at crisis times, as it disrupts the required balance between the densely packed areas of buildings and the open spaces available in cities. Enhancement of environmental quality and thermal comfort at these spaces can lead to people’s attendance and satisfaction. Security is the capability of the society of lying in a state that maintains its present conditions, identity, benefits, and basic characteristics in confrontation with evolved conditions and threats and the capability of improving the social conditions in accordance with the values ​​and ideals of the society. Factors directly impacting the degree an extent of thermal comfort include the physical characteristics of the environment such as the geometrics and shapes of buildings, the heights of the building surrounding the open space, the amount and type of vegetation, the orientations and locations of buildings with respect to the open space, the availability of semi-open spaces, and the amount of shading.

After library studies were conducted along with field studies enabling physical evaluation of the areas (viewing and recording site information) at the same time as 788 residents and tourists responded to questionnaires (thermal and environmental conditions), the climatic parameters (temperature, humidity, air flow rate, CO, and CO2) were recorded. Then, the rates of clothing and metabolisms of the individuals were calculated using software called Deltalog10. The resulting information was collected and subjected to another analysis, this time using SPSS24, and the thermal comfort range of the respondents was then specified with software called Ray Man. Next, the direct and indirect relationships between the variables were assessed using the structural equation model based on the Maximum Likelihood method in Amos.

The findings demonstrated that the outdoor shape and geometry of an open space as well as its type can affect thermal comfort, thermal compatibility, satisfaction with outdoor shape and geometry, satisfaction with the fabric and surrounding buildings, and people’s sense of security in open spaces. Thermal compatibility was greater at outdoor courtyards than at urban passage open spaces. The results indicated that people were more satisfied with the shapes and geometrics of outdoor courtyards than those of public roads. Moreover, satisfaction with outdoor shape and geometry developed thermal comfort in people. There was a greater sense of outdoor security at courtyards than at outdoor public passages, making people more thermally adaptable at open spaces.

The results indicated that the respondents had reached thermal comfort in a temperature range of 20.5 to 34.78°C (PET). Furthermore, organized outdoor geometry had direct impacts on the sense of security, with a coefficient of 0.15, on satisfaction with the fabric and buildings surrounding the open space, with a coefficient of -0.98, and on overall thermal comfort, with a coefficient of -0.8. It also exhibited indirect positive significant impacts on satisfaction with the shape and geometry of the open space and on thermal adaptability. Furthermore, the variable of the type of open space of the central courtyard had direct impacts with the highest coefficients on satisfaction with the compositional fabrics and buildings surrounding the open space, with a coefficient of 1.49, on satisfaction with the shape and geometry of the open space, with a coefficient of 0.97, on overall thermal adaptability, with a coefficient of 0.74, on the sense of security, with a coefficient of -0.23, and on overall thermal comfort, with a coefficient of -0.38. The interesting point to be noted in the analysis and interpretation of the model path concerned the key role played by the security variable as a factor effective in the occurrence of indirect relationships between variables.