Shahab Kariminia

Modelling thermal comfort of visitors at urban squares in hot and arid climate using NN-ARX soft computing method

Visitors utilize the urban space based on their thermal perception and thermal environment. The thermal adaptation engages the user’s behavioural, physiological and psychological aspects. These aspects play critical roles in user’s ability to assess the thermal environments. Previous studies have rarely addressed the effects of identified factors such as gender, age and locality on outdoor thermal comfort, particularly in hot, dry climate. This study investigated the thermal comfort of visitors at two city squares in Iran based on their demographics as well as the role of thermal environment. Assessing the thermal comfort required taking physical measurement and questionnaire survey. In this study, a non-linear model known as the neural network autoregressive with exogenous input (NN-ARX) was employed. Five indices of physiological equivalent temperature (PET), predicted mean vote (PMV), standard effective temperature (SET), thermal sensation votes (TSVs) and mean radiant temperature (Tmrt) were trained and tested using the NN-ARX. Then, the results were compared to the artificial neural network (ANN) and the adaptive neuro-fuzzy inference system (ANFIS). The findings showed the superiority of the NN-ARX over the ANN and the ANFIS. For the NN-ARX model, the statistical indicators of the root mean square error (RMSE) and the mean absolute error (MAE) were 0.53 and 0.36 for the PET, 1.28 and 0.71 for the PMV, 2.59 and 1.99 for the SET, 0.29 and 0.08 for the TSV and finally 0.19 and 0.04 for the Tmrt.

Urban outdoor thermal comfort prediction for public square in moderate and dry climate

Thermal condition is a decisive factor which impacts the use of outdoor spaces. Concerns on outdoor thermal conditions are on the rise judging by the growing number of research on the subject. However empirical research in the context of urban outdoor in moderate and dry climate is still limited. Predicting thermal comfort of outdoor spaces in a particular setting is essential to ensure continuous return of visitors and users. This paper aims to establish the thermal acceptable temperature range applicable for an urban context in temperate and dry climate zone based on the physiologically equivalent temperature (PET) index. Two fieldwork experiments were conducted through environmental measurements and questionnaire survey performed in winter of 2009 and summer of 2010 at a public square in Esfahan, Iran. These data were used for the thermal comfort assessment, supported by the RayMan model for the calculation of the mean radiant temperature (Tmrt) and PET. The study established the acceptable thermal comfort range to be between 12.3 and 30.9 deg C which is relatively wider then past studies.

Outdoor thermal comfort of two public squares in temperate and dry region of Esfahan, Iran

This paper presents a study on outdoor thermal comfort in a temperate and dry climate based on a field survey conducted in Esfahan, Iran. Studies on outdoor thermal comfort have mostly concentrated on street canyons and few on public squares. This study utilized ASHRAEs Thermal Sensation Vote (TSV) to assess peoples acceptance of the outdoor thermal comfort conditions with a data recording technique and observing thermal adaptation behavior of the people at two public squares in the heritage areas of the city. The fieldwork was a short-term survey during an extreme period of cold winter. The study was performed for a full week at each square in December 2009 and January 2010. Air temperature, RH, wind speed and solar radiation were measured. The preliminary results revealed that people visiting the squares in cold season mostly felt comfortable with the air temperature and sunlight. They prefered a higher humidity condition and a little more wind. Areas in the squares with water elements seemed to have attracted more people with majority of the respondents satisfied with the outdoor thermal condition resulting in higher percentage of TSVs within the three central categories. People seemed to prefer a square that offers longer episodes of sun-exposed periods and higher air movement in the winter.

Landscape Attributes, Microclimate and Thermal Comfort of an Urban Square in Moderate and Dry Climate

Recent rapid urban growth in major cities highlights the role of public squares, where their success can be gauged by its frequency of use and the outdoor thermal conditions. Despite the growing number of studies on outdoor thermal comfort in temperate and dry climate, those done in the Middle East are still limited. This paper examines the effects of landscape attributes on microclimatic conditions and outdoor thermal comfort based on the physiological equivalent temperature (PET) index in Esfahan, Iran. The thermal comfort prediction and correlation between thermal environment and the use of urban space were also explored. Two fieldwork studies were conducted through simultaneous environmental measurement and questionnaire survey in winter and summer at a public square in Esfahan. The obtained data became the basis for Tmrt (mean radiant temperature) and PET estimations, supported by RayMan model. The thermal environment was investigated with different landscape attributes. The derived thermal acceptable range was found to be considerably wider that those reported in previous studies. A strong correlation was confirmed between the thermal conditions and the use of outdoor spaces. The findings demonstrated the strong positive influence of air velocity and evaporative effect of water on thermal comfort. The findings contribute toward suitable design of public squares in climates similar to Esfahan.