عنوان مقاله [English]
The importance of finding urban open spaces in sustainable cities and striving to improve the quality of urban environments and increasing the activity of open urban spaces, it is imperative to develop efficient urban design approaches consistent with climate. Local micro-climates affect the thermal comfort of the environment, which is one of the most important factors in the desirability and dynamics of urban open spaces. On the other hand, local micro-climates have a close relationship with the physical elements of the environment such as the geometry and layout of urban blocks. The aim of this study was to compare and compare the effect of conventional urban block geometry and to find the factors affecting the thermal outdoor comfort in hot and cold seasons in Hamadan. The research method in this study included field measurement and computer simulation (ENVI-met software) of five conventional geometries of city blocks with sky-view factor (SVF), orientation and different layout (Single North-South Blocks, East-West Single Blocks, North-South Linear Blocks, East-West Linear Blocks and Central Yard Blocks) as five urban micro-climates evaluated in one The hottest days of the year according to the summer revolution and one of the coldest days of the year with the winter revolution. The average of the four factors of air temperature, average radiation temperature, relative humidity and wind flow rate were extracted as the most important factors affecting outdoor thermal comfort in the central space of the target blocks. To evaluate the results more accurately, the predicted mean vote (PMV) and physiological equivalent temperature (PET) indices are used as the most comprehensive methods for estimating outdoor thermal comfort. According to the results of the analysis of the data obtained from the software, the summer revolution increased the shading of the forms and consequently reduced the average radiation temperature and also increased the wind flow velocity in the central space of the forms which had a direct effect on the air temperature and conditions. Ambient heat helps to improve thermal conditions. On the other hand Conversely, in the winter revolution, thermal conditions are improved by increasing the average radiation temperature and decreasing wind speed. In general, the results of thermal comfort indices show that central courtyard blocks improve summer thermal comfort due to more daytime shading and in winter due to a severe decrease in cold wind flow rate than other forms. Although central courtyard blocks are better than other blocks mentioned in this study, the lack of wind speed in summer and reduced winter sun exposure are some of the weaknesses in this form. It seems that by eliminating these weaknesses an optimal form can be achieved in the urban blocks for the city of Hamadan. Such studies can help architects and urban designers achieve the best urban geometry to achieve high quality open spaces in the future development of cities.