Scientific- Research Quarterly of Geographical Data (SEPEHR)

Scientific- Research Quarterly of Geographical Data (SEPEHR)

Evaluating the impacts of climatic factors, especially quality and direction of the prevailing wind on thermal comfort using geographical models of a town square Case study: Nabovat Square in East of Tehran

Document Type : Research Paper

Authors
Zahra Servati 1
Gholamreza Latifi 2
1 Teacher in Azad uni
2 Associate professor,Department of social,urban and regional planning, Faculty of social sciences, AllamehTabatabaie University
10.22131/sepehr.2021.244466
Abstract
Introduction
Development of cities and vehicles used in urban areas have resulted inenvironmentalcrisisin most metropolises all over the world and caused physical and psychological damages to the residents of those areas. Comfort, especially thermal comfort, is one of the main factorsaffectingquality of space and people’s satisfaction in using that space. Thus, it is necessary to create a suitable environment for human beings through protection against adverse climatic conditions. Providing thermal comfort in open urban spaces is an important principle of urban planning, which affects physical and mental health of human beings and consequently, improves their performance. Compared toindoor and private spaces, fewer researches have focused on thermal conditions of public space, which is most possibly due tospatial diversity, wide range of activities performed in open spacesin urban areas, andthe complexity of parameters affecting outdoor comfort.Urban spaces are the scene in which the story of collective life unfolds. Thermal comfort in these areas is considered to be one of the most important and influential issues in various aspects of life. Natural ventilation in public urban spaces and squares is one of the best and cheapest methods of ventilation in which wind enters the urban square and its surrounding space resulting in thermal comfort of people in that area .

Materials & Methods
The present study evaluates and compares the impacts of two effective criteria of quality and direction of prevailing wind on thermal comfort in urban public spaces. These criteria are usedin a structural and physical model ofNabovat Square in east of Tehran with the aim of determining the most important and effective criterion in geographical modeling of urban squares.Therefore, different scenarios are defined changing several factors of direction, speed and wind quality in urban space in ENVI-met 4 basic environment.Through a three-dimensional simulation and measurement of urban microclimatic conditions,the level of thermal comfort in the study area is measured based on the PMV criterion (average temperature predicted in the modeling space).

Results & Discussion
Results indicate that identifying optimal geographical and geometric orientation of a building can play an effective role in getting the maximum benefits of prevailing wind while minimizing possible hazards of high winds, and thus creating thermal comfort for citizens. Another important issue is the effect of wind direction on urban public spaces. This is one of the main factors preventing an increase in the temperature range for comfort, and thus a proper direction of the prevailing wind will lead to thermal comfort in the study area.

Conclusion
Results of quantitative analysis inENVI-met 4 basic environment indicate that the most appropriate orientation of public urban spacesin Tehran is southwestwith a rotation of about 10 degrees. Assuming that several factors such as vegetation and physical properties of the surrounding buildings are constant, the present study has evaluated the impact of factors related to the direction, quality and wind speed. The impact of other factors should be considered in future studies. Finally, it is suggested that planting trees in a suitable place can decrease direct radiation and along with thespecific properties of buildings surrounding the square provide thermal comfort for citizens.In other words, surrounding buildings and the vegetation create an independent microclimate affecting thermal comfort.
Keywords
Square
Natural ventilation
Thermal comfort
Wind
1- امین دلدار، ساناز، (1392). آسایش حرارتی در فضاهای باز شهری و نمود آن در طراحی راسته شهری در اقلیم سرد، پایان نامه کارشناسی ارشد معماری، پردیس هنرهای زیبا، دانشگاه تهران.
2- پاکزاد، جهانشاه. (1385). راهنمای طراحی فضاهای شهری، تهران؛ انتشارات شهیدی.
3- پیرنیا، محمدکریم، (1389)، سبک‌شناسی  معماری، تدوین  غلامحسین معماریان  ویراستار علیمحمد رنجبر کرمانی، سروش دانش.
4- حیدری، منعام؛ شاهین، علیرضا، (1392)، ارزیابی معیاره ‌های آسایش حرارتی در فضای باز، جغرافیا و توسعه ناحیه‌ ای، شماره 20
5- دوستی - سینا، (1392)، بررسی روند تغییرات شاخص استاندارد آلودگی هوا در کلان شهر تهران در طی سال‌ های 1381- 1391،شانزدهمین همایش ملی بهداشت محیط ایران.
6- رحمتی، حیدری، بمانیان؛ مهدی، شاهین، محمدرضا، (1395)، بررسی راهکارهای طراحی معماری بر کاهش اثر جزایر حرارتی شهری، مجله انرژی ایران دوره نوزدهم، شماره 1
7- صفایی‌‌پور‌، م، (1389) ،بررسی تأثیر عناصر اقلیمی در معماری شهری:  مطالعه موردی شهر لالی‌، فصلنامه ‌پژوهـش و برنامه ‌ریزی شـهری، ش 2 ، صص 103-116.
8- ضرابیان، فرناز.(1389). طراحی فضاهای باز قابل دفاع در محلات مسکونی شهر تهران (مطالعه موردی: محله باغ فیض - پونک) پایان ‌نامه کارشناسی ارشد، دانشکده هنر و معماری، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران.
9- مجیدی، حیدری، قلعه‌نویی، قاسمی سیچانی؛ فاطمه‌السادات، شاهین، مریم، (1398). ارزیابی و تحلیل وضعیت آسایش حرارتی فضای باز محلات مسکونی با استفاده از شاخصه‌های حرارتی، نشریه علمی معماری و شهرسازی ایران.
10- محمدی، ذوالفقاری، کولیوند؛ کلثوم، حسن، طاهر، (1397)، شبیه ‌سازی شرایط میکروکلیمایی و آسایش حرارتی در معابر اصلی کلان ‌شهر کرمانشاه، فصل نامه جغرافیا و آمایش شهر منطقه‌ای، سال نهم، شماره 3  بهار 1398.
11- معاونت برنامه ‌ریزی طرح تهیه و تدوین برنامه آمایش استان،  (1397).
12- منتظری، جهانشاه ‌لو، ماجدی؛ مرجان، لعلا، حمید، (1397)، تأثیر مؤلفه‌ های فرم کالبدی شهری بر آسایش حرارتی فضاهای باز شهری  (مطالعه موردی: اراضی پشت سیلو شهر یزد)، فصلنامه مطالعات محیطی هفت حصار، سال ششم، شماره 23.
13- مهدوی ‌نژاد، محمدجواد،  (1394) ، مقاله نقش و تأثیر طراحی در کیفیت آسایش حرارتی فضاهای باز شهری  (بررسی موردی:  طراحی پیاده ‌راه طقماچی ‌ها در کاشان) ، فصلنامه دانشگاه هنر، ش  18، نامه معماری و شهرسازی، ص 59 .
14- Alcoforado, M.; Andrade, H.; Lopes, A. &Vasconcelos, J., 2009,“Landscape and Urban Planning Application of climatic guidelines to urban planning The example of Lisbon (Portugal)”, 90, 56–65. https://doi.org/10.1016/j.landurbplan.
15- Badran, M.A (2014),The Impact of Neighborhood Geometries on Outdoor Thermal Comfort and Energy Consumption from Urban Dwellings, Ph.D. Thesis, University of CARDIFF.
16- Berardi, U., & Wang, Y., (2016) , “The effect of a denser city over the urban microclimate: The case of Toronto”. Sustainability (Switzerland). https://doi.org/10.
17- Bogda . M, Prucnal–O, (2003) ,Choice of thermal  index  forarchitecturaldesign with climate in Nigeria  ;Habitat  international, Vol. 44
18- Bouden . C, Ghrab  . N. (2005) , An adaptive thermal comfort model  for  the Tunisiancontext: A field study result; Energy and Buildings, Vol. 37.
19- Cui, L. & Shi, J., (2012) ,“Urbanization and its environmental effects in Shanghai, China”. Urban Climate. https://doi.org/10.
20- Chatzidimitriou, A. &Yannas, S., (2015), “Microclimate development in open urban spaces: The influence of form and materials”.EnergyandBuildings, 108, 156–174. https://doi.org/10.1016/j.enbuild.2015.08.048
21- Chen, X.L. 2006. “Remote sensing image-based analysis of the relationship between urban heat island and land use/cover changes”, Remote Sensing of Environment, pp. 104-133.
22-  El-Bardisy, W. M.; Fahmy, M. & El-Gohary, G. F., (2016), “Climatic Sensitive Landscape Design: Towards a Better Microclimate through Plantation in Public Schools, Cairo, Egypt”. Procedia - Social and BehavioralSciences, 216, 206-216.
23- Gómez, F.; Cueva, A. P.; Valcuende, M. &Matzarakis, A., (2013) ,“Research on ecological design to enhance comfort in open spaces of a city (Valencia , Spain)”. Utility of the physiological equivalent temperature (PET).Ecological Engineering. https://doi.org/http://dx.doi.org/10.1016/j.ecoleng.
24- He, X.; Miao, S.; Shen, S. & Li, J., (2014) ,“Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature”. International journal of biometeorolog. (http://link.springer.com/article/10.1007%2Fs00484-014-0841-5)
25- Hwang, R.-L.; Lin, T.-P. &Matzarakis, A., (2011), “Seasonal effects of urban street shading on long-term outdoor thermal comfort”. Building and Environment,46(4), 863–870. https://doi.org/http://dx.doi.org/
26- Johanssson, E., (2006) ,Urban Design and Outdoor Thermal Comfort in Warm Climates, Stud ies in Fez and Colombo. LUND university.
27- Kaplan, S.; Peeters, A. &Erell, E., (2016) ,“Predicting air temperature simultaneously for multiple locations in an urban environment: A bottom up approach”.Applied Geography, 76, 62–74. https://doi.org
28- Kleerekoper, L., (2016) ,Urban climte design: improving thermal comfort in Dutch neighbourhoods. Delft University of Technology.
29- Krüger, E. L. L.; Minella, F. O. O. &Rasia, F., (2011), “Impact of urban geometry on outdoor thermal comfort and air quality from fi eld measurements in Curitiba ,Brazil”.Building and Environment, 46(3), 621–634. https://doi.org/10.1016/j.
30- Lenzholzer, S (2012), Research and design for thermal comfort in Dutch urban squares, Resources, Conservation and Recycling, Vol. 64, pp. 39-48.
31- Lilly Rose . A (2010) , Impact of Urbanization on the Thermal Comfort Conditions in the Hot Humid City of Chennai, India, Conference: Recent Advances in Space Technology Services and Climate Change .
32- Lin, T.-P., et al., ( 2010) , “Shading effect on long-term outdoor thermal comfort”.Building and Environment. 221-213.
33- Martins, T. A. L.; Adolphe, L.; Bonhomme, M.; Bonneaud, F.; Faraut, S.; Ginestet, S.; Guyard, W., (2016) , “Impact of Urban Cool Island measures on outdoor climate and pedestrian comfort: Simulations for a new district of Toulouse, France”. Sustainable Cities and Society. https://doi.org/10.1016/j.scs.
34- Spagnolo, J. & de Dear, R.,(2003) , “A field study of thermal comfort in outdoor and semi-outdoor environments in subtropical Sydney Australia”. Building and Environment. https://doi.org/10.1016/S0360-1323(02)00209-3
35 - http://www.tehranmet.ir/-