تاثیر تناسبات کالبدی بر عملکرد حرارتی ایوان ها در بافت تاریخی شیراز مبتنی بر بهبود شاخص آسایش حرارتی (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
تغییرات اقلیمی یکی از شاخص ترین واکنش های محیطی است که با افزایش جمعیت و رشد شهرنشینی بر محیط زیست پیرامونی خود تاثیر گذاشته است. لذا آسایش حرارتی در چنین محیط انسان سازی تحت تاثیر شرایط اقلیمی پیرامونی خودقرار گرفته است. بازجست راهبردهای بوم گرایانه از مهمترین اهداف این تحقیق در کاهش دمای محیطی بوده است. تناسبات عناصر اقلیمی در بدنه نما همچون ایوان ها، تاثیرات بارزی بر کاهش دما بر محیط اطرافشان داشته اند. در این راستا 4 ایوان با 4 جهت جغرافیایی در 3 خانه بافت تاریخی شیراز انتخاب شدند . این پژوهش با رویکردی کمی از روش میدانی جهت برداشت داده های آب و هوایی ، مولفه های فیزیکی و شبیه سازی توسط نرم افزار بهره برده است. نتایج مستخرج از آزمایش های تجربی که توسط دستگاه هایی هم چون ترموهیگرومتر و ترموپیرومتر بر روی نقاط مدنظر انجام شده، توسط نرم افزار Envi-met صحت سنجی شده است. در انتها با نرم افزار Bio-met شاخص آسایش حرارتیPET تعیین شد. نتایج پژوهش حاکی از آن بود که با توجه به تفاوت میانگین شاخص PET ایوان و حیاط خانه ها ، تعدیل گر ایوان بر این شاخص تاثیر بیشتری نسبت به حیاط داشته است، لذا متغیرهایی نظیر عرض ایوان، مساحت گشایش فضایی در نما و ارتفاع از سطح حیاط با توجه به جهت جغرافیایی حائز اهمیت بوده اند. با افزایش عرض بازشوها و افزایش ارتفاع از سطح حیاط و به دنبال آن دوری جستن از بازتاب های دمایی، در ایوان ها شرایط دمایی بهینه تری تجربه شده است.The Effect of Physical Proportions on the Thermal Performance of Porches in the Historical Fabric of Shiraz Based on the Improvement of Thermal Comfort Index
Climate change is one of the most significant environmental reactions that has affected the environment and along with increasing population, industrial expansion, and urbanization, has led to an increase in urban metabolism and changes in weather patterns. Therefore, thermal comfort, which is a satisfying thermal condition from the surrounding man-made environment, is affected by the surrounding climatic conditions. Historically, the temperature and providing thermal comfort has been one of the most important priority needs of users. In this regard, environmental compatibility, rereading and reproducing concepts in accordance with the environment have been essential. The main objectives of this research in reducing the ambient temperature are to retrieve vernacular strategies and identify the techniques that encompass the natural, cultural, traditional, and social conditions prevailing in an area. The proportions of climatic elements in the façade -the exchange of internal and external boundaries has been one of the main elements in temperature response and balance- including all physical points and vector constituents that form a space with an arch that is closed on three sides, and opened to the courtyard from the front, have shown significant effects on lowering the temperature of their surroundings. In this regard, four porches with four geographical directions (north, south, east and west) in the three houses (with historical antiquity and influential climatic elements like: Sadr Jahromi , Forough–al-Molk and Mohandesi) of Shiraz's historical fabric were selected. In this research, quantitative approaches such as field study and collection of climate data and physical components were used along with computational simulation. The field data and experimental results obtained by devices (portable instruments in the selected buildings) such as thermo-hygrometer to record maximum and minimum ambient temperature and humidity and thermo-pyrometer to measure surface temperature on the targeted points, such as yards and porches were analyzed and validated by Envi-met (climate analysis simulator) software. Lastly, PET thermal comfort index, physiological equivalent temperature and index for determining the comfort temperature in open and semi-open spaces, were calculated using Bio-met software (the impact of all climatic factors can be evaluated by the results of this index). The research results showed that according to the difference between the average PET index of porches and yards, the porch modifier had a greater effect on this index than the yard. Therefore, variables such as the width of the porch, the area of the spatial opening in the facade, and the height of the courtyard have significant impacts according to the geographical direction. By increasing the width of the openings and the height from the surface of the yard, followed by preventing temperature reflections, including long wave infrared radiation emitted based on heat received from surrounding materials and reducing the reception of these rays and their re-emission, the temperature of the PET index decreased, and the PET temperature was in a more appropriate range in terms of thermal perception and degree of physiological pressure. Also, better temperature condition and reduced thermal stress condition were experienced in the porches.
تبلیغات
