The Role and Impact of Design Elements on the Quality of Thermal Comfort in Urban Open Spaces Case Study: Design of Pedestrian Way in Tamghachiha Pathway in the City of Kashan

Document Type : Original Article

Authors

Abstract

Different climate conditions often result in different use of open spaces. The impacts of climate on the use of outdoor spaces in the urban environment are particularly important for quality and quantity of the activities that are carried out in the area. Thermal comfort is one of the most effectual factors on the quality of “place”, and promotion of thermal comfort quality would affect the vitality of the area. Cities significantly modify the meteorological conditions of surrounding areas: overall radiation is higher, except for ultraviolet radiation; the mean annual temperature is higher in cities than in the surrounding areas; wind speed is considerably lower in the cities, being slowed by buildings. As a consequence, relative humidity in cities is lower. Environmental conditions that body is exposed to can, however, be attenuated, filtered or enhanced by architectural means, e.g. a sunshade or vegetation can provide shading. But thermal comfort, especially in outdoor locations is a great challenge to assess, since numerous environmental, personal factors are involved: variation of sun and shade, changes in wind speed, and so on. Thermal comfort, in its basic definition, is the human reaction to the surrounding indoor or outdoor environments. More specific definitions of this term are summarized under three different categories: the psychological, thermo-physiological and energetic definitions. Background of studies about thermal comfort dates back to 1970s, but these studies focus on indoor thermal comfort quality. Attention to outdoor thermal comfort in urban design studies has started in the last decade. Research on outdoor comfort involves different conditions and issues, not encountered in studies on indoor comfort. Surveys in this field emphasized the need for investigating different ways to quantify comfort condition in outdoors. This research is to apply effective urban design techniques, such as shading devices, a selection of surface materials, vegetation and water bodies on the site, evaluating thermal comfort quality of an area and proposing optimum design alternative and modifying thermal comfort. This research is based on simulating thermal comfort quality, using ENVI-met software. This software was chosen because it is the only software where all factors influencing thermal comfort like wind speed and direction  , air temperature, etc. are simulated integrally to derive thermal comfort indices. PMV index was also chosen to quantify thermal comfort condition in the area. PMV relates the simple energy balance of the human body to thermal comfort experienced by a person, with normal values between -4 (very cold) and ‏4 (very hot). PMV was originally created to measure indoor human comfort, but later adapted to outdoor spaces by Jendritzky. In research process, three differences alternatives, based on various design solutions, were proposed for the area and simulated by ENVI-met software. Impact of each technique was evaluated through comparison of these three alternatives. In conclusion, based on simulation results, shading has a significant influence on thermal comfort, compared with other techniques such as surface materials, vegetation and water bodies, in microclimate scale. Moreover, using a combination of shading with other techniques especially water bodies reinforces reduction of temperature.

Keywords

References

-   حیدری، شاهین و منعام، علیرضا (1392) «ارزیابی شاخصه‌های آسایش حرارتی در فضای باز»، مجله جغرافیا و توسعه ناحیه‌ای، شماره 20، 197-216.
-   حقیقت نائینی، علیرضا (1389) «انگاره طراحی «فرم شهری پایدار» و شهر تاریخی مطالعه موردی: بررسی سکونتگاه‌های حوزه بیابانی استان اصفهان»، نامه معماری و شهرسازی، شماره 3، 41-65.
-   رضازاده، راضیه و آقاجان بیگلو، عماد (1390) «الگوی پیشنهادی برای توده گذاری در قطعات مسکونی ردیفی بررسی تطبیقی دو الگوی توده گذار در بلوک‌های مسکونی با معیار آسایش حرارتی»، نشریه نامه معماری و شهرسازی، 165-184.
-   طاهباز، منصوره (1388) «روش تحلیل آمار هواشناسی برای طراحی معماری همساز با اقلیم»، نشریه هنرهای زیبا، دانشکده هنرهای زیبا دانشگاه تهران، شماره 38، 61-72.
-   فلاح منشادی، الهام؛ حبیبی، سارا و روحی امیر (1391) «پیاده‌راه‌های شهری، از ایده تا عمل؛ ارزیابی پیاده‌راه بازار شهر تهران»، نامه معماری و شهرسازی، شماره 9، 63-45.
-   قیابکلو، زهرا (1380) «روش‌های تخمین محدوده آسایش حرارتی»، نشریه هنرهای زیبا، شماره 10، 68- 74.
 
-   Ali-Toudert, Fazia & Mayer, Helmut (2007) "Effects of asymmetry, galleries, overhanging facades and vegetation on thermal comfort in urban street canyons," Solar Energy, 81, 742-754.
-   Bruse, M. & Fleer, H. (1998) "Simulating surface-plant-air interactions inside urban environments with a three- simentional numerical model," Environmental Modelling and software, 13, 373-384.
-   Bruse, M. (2013) ENVI-met 3.1: model overview, Available online at: www.envi-met.com.
-   Carmona, Matthew & Tiesdell, Steve (2007) Urban Design Reader, Architectural press, Oxford.
-   Chappells, H. & Shove, E. (2004) COMFORT: A review of philosophies and paradigms, Lancaster University, available at: http://www.lancaster.ac.uk/fass/projects/futcom/fc_litfinal1.pdf.
-   Chen, Liang & Ng, Edward (2012) "Outdoor thermal comfort and outdoor activities: A review of research in the past decade," Cities, 29, 118-125.
-   Emmanuel, R. (2005) "Thermal comfort implications of urbanization in warm-humid city: the Colombo Metropolitan Region (CMR), Sri Lanka," Building and Environment, 40, 1591-1601.
-   Erell, Evyatar; Pearlmutter, David & Williamson, Terry (2011) URBAN MICROCLIMATE Designing the Spaces Between Buildings, Earthscan, London.
-   Givoni, B.; Noguchi, M.; Saaroni, H.; Pochter O.; Yaacov, Y.; Feller, N. & Becker S. (2003) "Outdoor comfort research issues," Energy and Buildings, 35, 77-86.
-   Gómez, F.; Pérez Cueva, A.; 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, 27, 27-39.
-   Höppe P. (1999) "The Physiological Equivalent Tempreture-a Universal Index for the Biometeorological Assessment of the Thermal Environment," Int. Biometeorology.
-   Höppe, P. (2002) "Different aspects of assessing indoor and outdoor thermalcomfort," Energy and Buildings, 34, 661-665.
-   Howard L. (2007) The Climate of London, IAUC edition available at www.lulu.com in two volumes.
-   Jendritzky, G.; Menz, G.; Schirmer, H. & Schmidt-Kessen, W. (1990) "Method of a regionoriented assessment of the thermal component of human bioclimate (UpdatedKlima-Michel model)," 114. Hannover: Beiträge Akad RaumforschungLandesplanung, 7-69.
-   Johansson, E. (2006) "Influence of urban geometry on outdoor thermal comfort in a hot dry climate: A study in Fez, Morocco," Building and Environment, 41, 1326-1338.
-   Kruger E.L.; Minella F.O. & Rasia F. (2011) "Impact of urban geometry on outdoor thermal comfort and air quality from field measurements in Curitiba, Brazil," Building and Environment, 46, 621-634.
-   Lenzholzer, Sanda (2012) "Research and design for thermal comfort in Dutch urban squares," Resources, Conservation and Recycling, 64, 39-48.
-   Perini, Katia & Magliocco, Adriano (2014) "Effects of vegetation, urban density, building height, and atmospheric conditions on local temperatures and thermal comfort," Urban Forestry & Urban Greening, 13, 495-506.
-   Szűcs, Á. (2013) "Wind comfort in public urban space- case study within Dublin Docklands," Frontiers of Architectural Reasearch, 50-66.
-   Taha, H. (1997) "Urban Climates and heat islands: albedo, evapotranspiration, and anthropogenic heat," Energy Build, 25, 99-103.
-   Taleb, H. & Taleb D. (2014) "Enhancing the thermal comfort on urban level in a desert area: Case study of Dubai, United Arab Emirates," Urban Foresty & Urban Greening, 13, 253-260.
-   Taleghani, Mohammad; Kleerekoper, Laura; Tenpierik, van den & Dobbelsteen Andy (2014) "Outdoor thermal comfort within five different urban forms in the Netherlands," Building and Environment, 1-14.
-   Thomson, Madeleine C.; Garcia-Herrera, Ricardo & Beniston, Martin (2008) "Seasonal Forecasts, Climatic Change and Human Health: Health and Claimate," Springer Science+ Business Media B.V.
-   Van Esch, MME.; Looman, RHJ.; & de Bruin-Hordijk, G. J. (2012) "The effects of urban and building design parameters on solar access to the urban canyon and the potential for direct passive solar heating strategies," Energy and Buildings, 47, 189-200.
-   URL 01 : http://www.model.envi-met.com/hg2e/doku.php?id=root:start (2016).
 
Journal of Architecture and Urban Planning
Volume 9, Issue 18
May 2017
Pages 59-80

Files

Share

How to cite

Statistics