Evaluating the thermal performance of wall construction materials* Case study: Residential buildings of Tehran

Document Type : Research Paper


M.Sc. in Environmental Design, Department of Architecture and Civil Engineering, University of Bath, Bath, England.


This study examines thermal performance of conventional wall construction materials and systems used in typical residential buildings in the city of Tehran; these materials are used instead of traditional heavyweight materials used in vernacular architecture of the region and represented appropriate potential in moderating outdoor weather conditions and providing thermal comfort for occupants. The necessity of this study is due to the important role of the building envelope, as an interface between indoors and outdoors, in control of the heat transfer and moderating weather conditions. With growing concern about climate change and global approach to cut CO2 emissions, application of construction systems which can help reduce energy consumption and associated carbon emissions are desired. As the wall area constitutes the largest part of the building envelope, its contribution to heat loss through the fabric is significant. Moreover, due to growing rate of the number of residential buildings in Tehran, there is a great potential of energy saving in improvement of the residential building’s envelope. The steady state thermal analysis is not an appropriate/ sufficient way of evaluating thermal performance of the building envelope as the indoor condition is the result of the dynamic response of the building fabric energy system to dynamic outdoor weather conditions. Therefore, apart from insulating capacity of the wall, its useful thermal mass which is a function of heat capacity, density and thermal conductivity of the composing layers of the wall, has an important role on its cyclic performance especially when the outdoor temperature starts cycling below and above indoor temperature. Therefore, a dynamic simulation tool (IES-VE) was used to analyse thermal performance of common wall construction alternatives in Tehran. These wall types are mostly made of hollow clay, LECA (Lightweight Expanded Clay Aggregates) and AAC (Autoclaved Aerated Concrete) blocks in combination with insulating materials (Expanded Polystyrene) and were tested on a reference building selected as a sample of typical residential buildings in Tehran. Indoor temperature resulted by each wall type was plotted against comfort temperature of the residents of Tehran in order and the deviation on indoor temperature from comfort temperature was measured to evaluate the level of comfort provided by each of these construction details. According to the results from the simulations, wall type L2 made of two layers of LECA blocks (100 mm) with a layer of polystyrene (50 mm) in between has the best performance in terms of providing indoor comfort condition among total six wall types introduced. Results show that there is a potential of 50% energy saving by application of wall type L2 instead of L1 (made of 200 mm hollow LECA blocks) which have the best and worst performance in terms of deviation of indoor temperature from comfort temperature


فهرست منابع
حیدری، شاهین (۱۳۸۸)، دمای آسایش حرارتی مردم شهر تهران، مجله هنرهای زیبا (معماری و شهرسازی)، ۱ (۵)، صص ۵ – ۱۴.
وبسایت رسمی سازمان آمار ایران (۱۳۹۱)، برآورد جمعیت ( آنلاین)، قابل دسترس از آدرس: http://www.amar.org.ir/Default.aspx?tabid=1160.
وبسایت رسمی مرکز تحقیقات راه، مسکن، شهرسازی (۱۳۸۸)، تکنولوژی‌های نوین ساختمانی [ آنلاین]، قابل دسترس از آدرس زیر:
Balaras, C.A.(1996), The role of thermal mass on the cooling load of buildings, An overview of computational methods, Energy and buildings, 24, 1-10.
CIBSE(2006), Environmental design: CIBSE guide A. 7th ed. Great Britain, Page Bros.
Clay brick and paver institute (CBPI)(2006), The role of thermal mass in energy-efficient house design, Australia, Austral bricks.
Crawley. D, Hand. J, Kummert. M, Griffith. B(2005), Contrasting Capabilities of Building Energy Performance Simulation Programs, US Department of Energy, University of Strathclyde, University of Wisconsin.
Department of climate change and energy efficiency (DCCEE), 2010. Your home; technical manual (fourth edition), Commonwealth of Australia [online]. Available from: http://www.yourhome.gov.au/technical/fs49.html#where .
De Saulles, T.(2011), Thermal mass explained, TCC (the concrete center), Surrey.
Doyle, M.D.(2008), Investigation of dynamic and steady state calculation methodologies for determination of building energy performance in the context of the EPBD, Thesis (M.Phil.), Dublin institute of technology.
Givoni, B.(1998), Climate considerations in building and urban design, The USA, Van Nostrand Reinhold.
Gregory, K., Moghtaderi, B., Sugo, H., Page, A.(2008), Effect of thermal mass on the thermal performance of various Australian residential constructions systems, Energy and buildings, 40, 459-465.
Hegger, M., Fuchs, M., Stark, Th., Zeumer, M.(2008), Energy manual; sustainable architecture, Berlin, Birkhauser.
Kruger, E., Cruz, E.G., Givoni, B.(2010), Effectiveness of indirect evaporative cooling and thermal mass in a hot arid climate, Building and environment, 45, 1422-1433.
Laughton, M.A., Warne D.F.(2003), Eectrical engineer’s reference book.
McMullan, R.(2007), Environmental science in building, 6th ed, New York, Palgrave Macmillan.
Nasrollahi, F.(2012), Urban and architectural criteria for reducing building energy consumption, National energy committee of Iran.