عنوان مقاله [English]
The level of thermal comfort in urban open spaces plays an important role in pedestrian health. Residential environments and open spaces of housing units require more comfortable temperatures. Courtyards as microclimate modifiers and common open spaces between urban and architectural scales can be a good passive strategy to increase thermal comfort and reduce energy demand of buildings. Therefore, it is necessary to quantify their temperature balancing effect in the prevailing summer and winter climates. Different urban forms provide different microclimates with different levels of comfort for pedestrians. The effects of urban microclimates on urban air quality and building energy use make them significant at a larger scale. Urban forms, shaped by the typology of buildings and the open space between them, have different impacts at different seasons. They meet the demand for compactness in summer to provide shelter from the sun and openness in winter to provide access to the sun. Therefore, to design a form that provides the best thermal conditions throughout the year, through the design of openings in the open space openings - height and width and position of the opening. In recent years, there has been increasing interest in the design of courtyards for microclimatic improvement of outdoor spaces. However, there is still little knowledge about the thermal performance characteristics of courtyards, especially in cold and semi-arid climates.
In this study, we measure the effects of different forms of courtyards on thermal comfort and climatic forces, including wind and radiation, using ENVI-met software by selecting a neighborhood unit in Sabzevar city. To this end, we have kept all design factors constant, including the height of adjacent blocks, vegetation, and materials, except for the openings of the adjacent courtyard. We studied the forms of the interrupted central courtyard, the closed central courtyard, and the U-shaped courtyard, and compared the thermal comfort of the open space in terms of the UTCI and PET indices. These three forms of the inner courtyard were analyzed for the hottest and coldest day so far in the cold and semi-arid climate of Sabzevar. ENVI-met was used to simulate outdoor air temperature, mean radiant temperature, wind speed, and relative humidity, and to convert these data to Physiological Equivalent Temperature (PET) and universal thermal climate index (UTCI).
The results show that the air temperature, mean radiant temperature, wind speed, and relative humidity are affected by the shape of the courtyard and the openings and play an important role in achieving optimal thermal comfort. The results show that the enclosed courtyard provides better protection from wind and radiation in this cold and semi-arid climate and is more successful from the point of view of thermal comfort. The results show that the enclosed courtyards provide better protection from wind and radiation in this cold and semi-arid climate and is closer to the thermal comfort range than the U-shaped courtyards from the thermal comfort point of view, with 4.88 and 7.73 degrees in the summer solstice and 4.01 and 1.28 degrees in the winter solstice in the UTCI and PET indices, respectively.