Stablishment of Optimum Designing Pattern in Buildings Roof Shape Based on Energy Loss

Presently، energy suppliment is considered as a pivotal economic and political characteristic in government; so that، an increasing trend in energy price appears in countries namely Iran due to energy resources limitation and increasing costs in extraction and exploitation. Therefore، parallel to efforts made to tackle the energy upgrading costs and lackness، improving energy efficiency and conservation in buildings are considered as main solutions to address the problem. Addition to applying thermal insulation in buildings، it is extremely significant to emplement energy-efficient strategies and approaches to decrease energy transfer rate in construction sector. Undoubtedly، following approaches positively influence buildings energy balance over a year. Directly influenced by climatic condition، building elements specifically، roofs، play an important role in heat transfer rate in a structure There are thermal exchange between roof and ambient temperature including: 1) Heating ignorence 2) Heating absorption 3) and finally solar reflectance). Furthermore، roof coverings compose a large area of buildings envelope; accordingly، it has a major impact on energy consumption and thermal comfort even considering construction roofs area in urban scale. Regarding to previous research experiences، there is a large scope of data on buildings envelope details to level down energy consumption; however، less studies are devoted to building elements shape to formally analyze energy consuming. The following paper develops the studies on roofs shape thermal behavior based on building heating load; while it uses a computerized simulation methodology as an alternative to field-based research. The simulation weather date is based on Isfahan city، in Iran. Modeled and analysed four roof covering types (flat roof، domed roof، pitched roof (30°-60°)، pitched roof 45°)، the final result shows that however the flat shape roof appears in an appropriate thermal performance، (30°-60°) pitched covering (mostly faced to the south in terms of surface) is regarded as the most energy-effecient form in Isfahan hot and dry climate area while domed shape roof appears in mostly inefficient sample to apply as covering in the area owing to most surface area. Moreover، the graphs show that applying thermal insulation as a layer in different roof shapes، remarkably decreases heating load over a montly simulation.