Document Type : Original Article

Authors

1 Department of Architecture and Urbanism, Shahrood University of Technology, Shahrood, Iran.

2 Shahrood Azad University, Shahrood, Iran.

10.22044/rera.2021.10512.1048

Abstract

In urban open spaces, especially in large cities with warm climates, users are experiencing high thermal loads, which causes thermal discomfort. Thermal comfort in open spaces can be improved; by shading. The problem is shading and protecting open spaces from stresses caused by overheating of the earth's surface and environment. The importance of shade and reducing radiation in achieving thermal comfort in open urban spaces is to increase human presence, create climate change, increase comfort conditions. Recognizing factors that create shadows, such as canopies and their characteristics, can create a favorable space to enjoy the capabilities of outdoor space. New membranes have many characteristics of nomadic tents, and, due to creating shade and natural ventilation, are very suitable for areas with hot climates. Introducing an optimal model and dimensions of a lightweight membrane canopy can create outdoor thermal comfort and increase the efficiency of outdoor spaces. In this paper, library, field, and simulation studies have been used. According to field studies, the presence of membrane canopy can cause temperature differences up to 7.8 C. The simulation results with Ansys, ENVI-met, and Ladybug showed that the membrane canopy cools the space below and prevents overheating. Between four canopy models, the saddle canopy is suitable with a 40.63% impact on the environment and creates cooler space under the canopy. Therefore, a lightweight saddle membrane canopy with dimensions of 5*5 m^2 and a useful height of 3 meters is introduced as a suitable model of membrane canopy for the hot climate of Semnan.

Keywords

[1]. Beer, A.R., Higgins, C. (1381). Environmental planning for site development: A manual for sustainable local planning and design. Tehran University Publications. Tehran.

[2]. Halabian, A.H. (1387). Analysis of climatic comfort in Isfahan. Geographic Notion, Vol. 3, No. 20.

[3]. Mohammadi, H., Saeedi, A. (1387). Effective bioclimatic indexes on human comfort assessment (Case study: Ghom city). Journal of Environmental studies, Vol. 34, No. 47.

[4]. Fanger, P.O. (1970). Thermal Comfort Copenhagen. Denmark: Danish Technical Press.

[5]. Adeniji, N.O., Adeniji, J.O., Ojeikere, O. (2020). Global Solar Radiation, Sunshine-hour Distribution, and Clearness Index: A Case Study of Sub-Sahara Region in Nigeria. Renewable energy research and applications, Vol. 1, No. 2, pp. 161-174.

[6]. Givoni, B., Noguchi, M., Saaroni, H., Pochter, O., Feller, N. et al. (2003). Outdoor comfort research issues. Energy Build, No. 35, pp. 77-86.

[7]. Middel, A., Selover, N., Hagen, B., Chhetri, N. (2016). Impact of shade on outdoor thermal comfort—a seasonal field study in Tempe, Arizona. Int J Biometeorol 60. pp. 1849-1860.

[8]. Rosenfeld, A.H., Akbari, H., Bretz, S., Fishman, B.L., Kurn, D.M., Sailor, D., Taha, H. (1995). Mitigation of urban heat islands: materials, utility programs, updates, Energy. Buildings, Vol. 22, No. 3, pp. 255–265.

[9]. Santamouris, M. (2007). Advances in Passive Cooling (Buildings, Energy and Solar Technology Series). Earthscan Publications Ltd.

[10]. Ren, C., Ng, E.Y.Y., Katzschner, L. (2011). Urban climatic map studies: a review, Int. J. Climatol, Vol. 31, No. 15, pp. 2213–2233.

[11]. Kantor, N., Chen, L., Gal, C.V. (2018). Human-biometeorological significance of shading in urban public spaces—Summertime measurements in Pecs, Hungary, Landscape Urban Plan 170, pp. 241–255.

[12]. Ahmed, K.S. (2003). Comfort in urban spaces: defining the boundaries of outdoor thermal comfort for the tropical urban environments. Energy and building, 35, pp. 103-110.

[13]. He, J., Hoyano, A. (2009). Measurement and simulation of the thermal environment in the built space under a membrane structure. Building and Environment 44, pp. 1119–1127.

[14]. He, J., Hoyano, A. (2010). Measurement and evaluation of the summer microclimate in the semi-enclosed space under a membrane structure. Building and Environment 45, pp. 230–242.

[15]. Xu, M., Hong, B., Jiang, R., An, L., and Zhang, T. (2019). Outdoor thermal comfort of shaded spaces in an urban park in the cold region of China. Building and Environment 155, pp. 408-420.

[16]. Lin, T., Matzarakis, A., Hwang, R. (2010). Shading effect on long-term outdoor thermal comfort. Building and Environment 45, pp. 213-221.

[17]. Lin, T., Matzarakis, A., and Hwang, R. (2011). Seasonal effects of urban street shading on long-term outdoor thermal comfort. Building and Environment 49, pp. 863-870.

[18]. Sultana, L. & Bari, N. (2019). A Study on the Impact of Tensile Fabric Structure in Semi-Outdoor Spaces of Tropical Cities. International Journal of New Innovations in Engineering and Technology.

[19]. Salvadori, M.G. (1393). Structure in architecture: The building of buildings. Tehran University Publications. Tehran.

[20]. McDonald S.A. (1382). Structure and architecture. Soil Publications.

[21]. Bridgens, B.N., Gosling, P.D., and Birchall, M.J.S. (2005). Tensile fabric structures: concepts, practice and developments. The structural engineers, pp. 21-28.

[22]. Forester, B., Mollaert, M. (2004). European Design Guide for Tensile Surface structures. Brussels: Tensinet publisher.

[23]. Golabchi, M., Taghizade, K., Golabchi, M. (1394). Structural systems. Pars University Publications. Tehran.

[24]. Mirlohi, S.M., Sadeghzadeh, M., Kumar, R., and Ghassemieh, M. (2020). Implementation of a Zero-energy Building Scheme for a Hot and Dry Climate Region in Iran (a Case Study, Yazd). Renewable energy research and applications, Vol. 1, No. 1, pp. 65-74.

[25]. Kasmaee, M. (1379). Climatic design zoning and guideline for hot and arid zones (Semnan province). Building and Housing Research Center. Tehran.

[26]. Huang, K., Yang, S., Matzarakis, A., and Lin, T. (2018). Identifying outdoor thermal risk areas and evaluation of future thermal comfort concerning shading orientation in a traditional settlement. Science of the Total Environment 626, pp. 567-580.

[27]. ANSI/ASHRAE, Standard 55 thermal environmental conditions for human occupancy. URL: https://www.ashrae.org/technicalresources/bookstore/standard-55-thermalenvironmental-condition.