The Effects of Physical Parameters of Buildings on Energy Consumption Fatemeh Bateni**Department of Architecture and Urbanism Engineering, Qazvin Islamic Azad University, Qazvin, IranEmail: fatemeh.bateni87@gmail.comAbstractNowadays, over 40% of energy consumption in the world occurs in the building sector. Given such a significant impact, designing buildings with long-term energy efficiency is of substantial importance. The purpose of the present study is to assess the thermal performance of a vast spectrum of parameters, including building orientation, window-to-wall ratio, transparency, and geographical direction in a cold and temperate climate. To this end, a case study is conducted on eight samples of prevalent building plans in Ilam city, located in the west of Iran. The results of the data analysis were written as mathematical functions, and ultimately, the proposed pattern function related to the four selected criteria of the optimal pattern was presented by comparing the functions of thermal comfort and natural lighting. In conclusion, square-shaped plans are the most optimal, and higher length-to-width ratios lead to higher energy consumption.Keywords : Physical Parameters; Residential Buildings; Energy Consumption; Square-shaped Plans; Building DesigningIntroductionIn every country, the building sector is responsible for more than one third of the total energy consumption (1). As a result, the amount and methods of energy consumption in buildings have always been a concern in construction projects. However, such a concern can be considerably mitigated by using modern technologies and adhering to the existing construction standards. In many countries, the shape and form of buildings are chosen based on climate conditions, which in turn affect how energy is consumed; in other words, the forms of buildings are selected through strategies that are suitable to the climate (1). Accordingly, the most important related indices include the type of materials, building orientation, thickness of walls, openings, and type of ceiling (2, 3). Attention has been paid to these indices, and today, architects also take them into account when reviewing the rules and changes to optimize energy consumption and lessen the consequences of unregulated consumption.The direct or indirect consumption of fossil fuels in buildings emits a large amount of CO2 into the atmosphere. Contemplating and recognizing the means to reduce CO2 production and consume energy in an optimal manner are instrumental to confronting the incorrect use of energy (4-6). This amount of emission amounts to nearly 40% of the entire CO2 (i.e., 842 million tonnes per year) (7), which entails 36% of the global energy consumption (8-10). Today, energy saving refers to the implementation of solutions specified under various regulatory frameworks (11, 12). Global guidelines on the energy performance of buildings require the adoption of tools for calculating energy consumption performance, applying the minimum performance standards during the design process, operating the construction, licensing the building, and ensuring control over heating and cooling systems (13-15). In fact, interior thermal comfort is considered the main driver of energy consumption in buildings (11, 16, 17), which can be of importance in two areas, including the type of consumed and the physical factors involved in energy consumption and suitable efficiency.Due to the inevitable degradation in their physical performance, many of the existing buildings are unlikely to be regarded as “green” buildings in terms of energy consumption. The physical performance of buildings should be specified in detail prior to any construction or system maintenance operations (18-20). There are numerous studies conducted on areas such as consumer behaviour, construction operation and system repair and maintenance, envelope function, lighting, hot water and heating systems, building materials, and HVAC (heating, ventilation, and air conditioning); these studies have offered a variety of models on energy reinforcement strategies and economic assessment of different types of existing structures in residential and non-residential buildings (21, 22).In Europe, the AR ranking, which assesses the physical performance of buildings, is used to enhance the energy performance of degraded buildings. This method provides reliable information regarding how energy is consumed or wasted in these types of buildings, with the ultimate purpose of reducing energy consumption and specifying the effect of each physical dimension on the amount of energy consumption. Nonetheless, collecting consistent data on the existing buildings is difficult, and the energy performance assessment of these buildings is commonly done using simplified data obtained from refined data and tables from different sources (23, 24). The same approach is adopted in this study.Numerous studies conducted in this area have examined optimal building designs; therefore, many more passive solutions have been proposed regarding energy reduction and efficiency in the building sector. Studies have shown that the energy performance of buildings depends on five factors, including weather, building design, urban geometry, system efficiency, and residents’ behaviour (25). According to evidence, the architectural design helps to reduce energy consumption (26, 27). In design and construction principles, inactive design strategies and bioclimatic designs are the main solutions to minimize energy demand (28). Studies have classified building designs into six parameters, which include the shape of the building, transparent surfaces, orientation of the building, thermal-physical features, building materials, and distances between buildings (29, 30).Clearly, energy source provision is one of the future concerns of mankind. The essential actions to mitigate these concerns may include controlling energy consumption, using clean energies, and employing modern knowledge for constructions with minimum energy consumption (31).In the present study, the design and construction of buildings in cold, temperate, and Mediterranean climates are highlighted. The empirical designing and constructing of buildings via different materials has, in many cases, offered substantially suitable potentials to create buildings that consistently involve optimal energy consumption. These indices have been mostly related to available materials, consistency between the climate and buildings, and the method of using renewable energies through building architecture, acquired through experiment over time. Given changes in lifestyle, fuel diversity, economic costs, family behaviour, available materials, and climate change, it appears that previous methods cannot meet the requirements of optimal energy consumption. Given such a fact, it is necessary to employ the technology of today’s world to optimize these indices and make use of new energy consumption methods in buildings. All in all, reducing energy consumption in buildings requires accurate, practical answers to the issue. As a result, the present study seeks to examine the effect of buildings’ physical features on the extent of energy consumption; further, different types of buildings and prevalent architectures in this study were compared to calculate energy consumption in various forms and provide suitable strategies for optimizing energy consumption in these buildings.Materials and MethodsThe present research is an applied, design-based study conducted using the analytical approach. The purpose of the study was to evaluate the physical parameters of residential buildings with the prevalent edge ratios in Ilam City – located in Iran – in order to provide an optimal pattern relative to the assessed parameters. Accordingly, eight prevalent residential building plans with the same total area (156 m2) were taken into account (Samples A, B, C, D, E, F, G, and H).Generally, the A/C and lighting systems in a residential building account for 40% and 11% of the total energy consumption, respectively. The eight samples in this study were examined in terms of thermal performance and lighting of the entire building. The physical characteristics of buildings, such as materials and the type of openings, were considered the same across all eight samples in the data analysis. Materials used in this study are as follows: