Residential Buildings In Tehran Research Articles

Implementing a rainwater harvesting system in an arid region with an LCA approach

AbstractThe purpose of this study is to compare the life cycle assessment and reliability of different rainwater harvesting (RWH) systems in residential buildings in Tehran for a period of 50 years. Four main scenarios based on the number of stories (1, 2, 3, and 4) each including five sub-scenarios based on the size of the rainwater storage tank (2.5m3, 5m3, 7.5m3, 10m3, 12.5m3) and one using solely tap water were defined. Simapro software was used for life cycle assessment which was carried out using the endpoint and midpoint methods. The collected rainwater is assumed to be merely used to fill flush tanks and if it cannot satisfy this demand, tap water will be used. The results show that in an arid city like Tehran, collecting rainwater does not even come close to meeting non-potable water needs, and in most scenarios, tap water must be used for more than half of the days. Despite the low reliability of RWH systems, they perform better than tap water in most environmental impact categories because the processes used to produce tap water have the highest contribution to environmental damage. Among the sub-scenarios that use rainwater for flush tank demands, in almost all environmental impact categories, sub-scenarios that collect more rainwater (higher storage tank sizes) have better performance. The performance of sub-scenarios that use more rainwater is better in the endpoint environmental categories of ecosystems and human health; however, this trend is the opposite in the impact category of resources. Graphical abstract

Optimization of construction costs and energy consumption during the operation period of residential buildings (Case study: common residential buildings in Tehran)

Optimization of construction costs and energy consumption during the operation period of residential buildings (Case study: common residential buildings in Tehran)

An in-depth thermo-electrical evaluation of a rooftop PV technology for a residential building using advanced infrared thermography

The investigated performance criteria of photovoltaic (PV) modules in the studies have been limited to current, voltage, power, and temperature. It means that a study with the aim of a comprehensive investigation of a number of key thermo-electrical indicators of the system, namely, photocurrent (Iph), parallel resistance (Rp), thermal voltage of diode (Vt), and diode reverse saturation current (I0), has not been done yet. Considering this point, a PV system installed on the roof of a residential building in Tehran, Iran, is experimentally studied here. For this system, the data gathered during a year is employed to find the values of the four indicated thermo-electrical characteristics. In order to enhance the accuracy, advanced infrared thermography is utilized, in which the photos taken by the thermal imaging camera is processed with developed code on the MATLAB interface. The results show that thermo-electrical indicators of the PV system change significantly throughout the year. With 32.3%, Vt is the indicator with the lowest annual variation. Rp and Iph change 1004.1 and 1943.9%, respectively, as well. Moreover, the simultaneous application of cooling techniques and concentrating strategies is suggested as a very efficient way to enhance the system performance.

Estimating annualized earthquake loss for residential buildings in Tehran, Iran

A probabilistic seismic risk assessment is conducted in this study to quantify Annualized Earthquake Loss (AEL) of Tehran, the capital of Iran. To do so, a comprehensive review of three main components of risk assessment including the seismic hazard analysis, exposure model and vulnerability functions is performed. The classical seismic hazard analysis is carried out based on the most recent earthquake catalog by considering the available uncertainties. A high-quality building exposure model based on recent census data with geographic resolution of census blocks is also compiled. According to available information, buildings are classified into 19 groups by considering their construction material, quality and height. The results show that sum of AEL in Tehran is about 10,488 million USD, which is equivalent to 0.16% of exposed economic value. The spatial distribution of AEL indicated that value of AEL in the eastern districts is higher; however, the relative seismic risk in term of AELR in the southern districts of the city is much higher. In addition, a disaggregation analysis per building typology is performed to identify the contribution of different building taxonomies in AEL. The results show that the masonry and low-quality steel and concrete structures with poor designing specifications have the highest contribution in AEL. The finding from this study can be used by local authorities, government and insurance sector in order to develop effective risk mitigation plans and a robust insurance scheme for Tehran, Iran.

Electricity Supply Model of Conventional Residential Buildings in Tehran with Priority on Renewable Energy Using Adaptive Fuzzy-neural Inference System

Electricity Supply Model of Conventional Residential Buildings in Tehran with Priority on Renewable Energy Using Adaptive Fuzzy-neural Inference System

Energy, economic and comfort optimization of building retrofits considering climate change: A simulation-based NSGA-III approach

Improving building energy performance is central to promote sustainability and mitigate climate change, but it has proved to be a challenging process requiring investigation of a large domain of energy retrofit measures and contrasting objectives. Besides, the unique characteristic of Iran, namely heavily subsidized energy prices and tiered utility rates, further complicate the problem. This research introduces a novel simulation-based multi-objective optimization approach based on a modification of NSGA-III algorithm, denoted as prNSGA-III, powered by parallel computing design and result-saving archive that offers an increased computational potential. The method is developed by integrating EnergyPlus as energy simulation engine with optimization algorithm coded in MATLAB programming language. A large domain of active, passive, water conservation, and renewable retrofit measures are explored to maximize environmental performance while minimizing thermal discomfort and life cycle cost. The method is applied to a residential building in Tehran, Iran, subjected to different scenarios with reference to future climate change and energy price variation. The results show that implementing suggested energy retrofit measures can yield substantial improvement in environmental performance and curb CO-eq emission by up to 73%, and also reduce thermal discomfort by up to 46%. However, energy-efficient solutions can only be achieved at the expense of increased life cycle cost. Moreover, the result demonstrates that climate change can affect optimal solutions, particularly heating and cooling systems, due to changes in external thermal loads.

Techno-economic evaluation of a hybrid photovoltaic system with hot/cold water storage for poly-generation in a residential building

There is a growing effort towards the application of solar technologies to meet electrical and thermal demand. However, substantial energy is used in buildings around the world for electricity and thermal comfort. Here we evaluate a novel hybrid solar-powered system for reducing the load on the direct expansion and heat pump unit of a combined heating and air conditioning system while generating electricity. The system combines rooftop photovoltaic (PV) and building-integrated photovoltaic thermal (BIPV/T) systems for electricity generation, while any excess electricity is used to drive a hot and cold water storage system. A residential building in Tehran is used as a case study, and the results are computed via MATLAB, TRNSYS, and Carrier HAP software. The system is shown to outperform both rooftop PV and BIPV/T systems alone, generating at least 50% more electricity while reducing the heating and cooling loads on the machinery by at least 60%. The system also enjoys a payback time of 2.87 years. The impact of thermal comfort setpoints, in addition to inflation and discount rates, are also evaluated via a sensitivity analysis involving several key performance metrics, namely the hot and cold water storage volumes, the size of the desiccant wheel, and the payback time. The cooling load is found to have the greatest influence on the cold water storage volume and the desiccant size, with 80.1% and 41.2% variations for baseline variations of ±20%. With a 57.7% increase, the heating load is found to have the biggest influence on the hot water storage volume. With a 27.1% variation, inflation has the strongest effect on the payback time.

Integrated value model for sustainability assessment of residential solar energy systems towards minimizing urban air pollution in Tehran

Renewable energy applications are lucrative alternatives to minimize urban environmental impacts. Solar energy, the most abundant, inexhaustible, and cleanest of all renewable sources, provides an opportunity to transform buildings from energy consumers into active energy producers. Nevertheless, photovoltaic (PV) and hybrid photovoltaic/thermal (PV/T) are considered the most viable alternatives for urban settlements. This study, as part of a broader research project, develops a new model to evaluate solar systems' air pollution mitigation capacity and assist decision-makers in adopting the most suitable solution. The approach is based on the integrated value model for sustainability assessment (MIVES), combined with the analytic hierarchy process (AHP) and sensitivity analysis. This multi-objective tool is applied to residential buildings in Tehran, a megacity example with unused rooftops, solar energy harvest potential, and air pollution reduction needs. Results reveal one square meter of PV and PV/T enables avoiding 211 and 488 kg CO2 emissions annually, as well as 1.2 and 1.9 g PM pollutants, respectively. Although PV achieves higher sustainability indexes as a better socio-economic alternative, PV/T can be a robust solution when stakeholders are more sensitive to environmental requirements and air pollution decrement potential. The critical obstacle to PV/T deployment is the lack of financial incentives. However, allocating 38 % of solar electricity feed-in tariffs to solar thermal energy could solve this issue. Compared to green roofs, solar systems stand out with CO2 saving and energy production potential. Researchers expect future solar collectors’ improvements, such as lower resource consumption, thus, becoming more environmentally friendly and cost-effective solutions.

Thermal performance of balcony thermal bridge solutions in reinforced concrete and steel frame structures

Thermal bridges in balconies considerably affect the overall thermal transmittance of building envelopes and are the main cause of building defects such as condensation, mold formation, and degradation of materials. The aim of this study is to conduct an evaluation of the impact of two thermal bridge solutions in common balcony connection details of residential buildings in Tehran, Iran. Through three-dimensional simulation, 33 scenarios of various balcony connection details, as well as adjacent wall assemblies are examined with and without thermal bridge solutions to evaluate the impact of these solutions on the thermal coupling coefficient of balcony connection, balcony linear thermal transmittance, and temperature factor at the internal surface. The simulation process is conducted using the heat transfer module of the three-dimensional simulation program COMSOL 5.2.an under steady-state conditions. The results demonstrate that concrete-concrete connections compared to steel-steel and concrete-steel connections are influenced more by thermal bridge solutions. Considering all scenarios, implementation of these solutions leads up to 44.5% and 75% reduction in thermal coupling coefficient and linear thermal transmittance respectively, depending on the wall and floor materials. Results obtained by examining a case study with different balcony and window options also highlight the importance of applying a thermally insulation balcony connector which reduces the normalized total heat transfer coefficient of building façade up to 12.2%. The findings of this study highlight the effectiveness of different technical solutions for reducing balcony thermal bridges in both steel and concrete structure balcony connections. Also, applying the balcony thermal bridge solutions evaluated in this research can remove the limitations against the insulation method of “very low energy” buildings based on the Code. No. 19 of Iran.

The real-time dynamic multi-objective optimization of a building integrated photovoltaic thermal (BIPV/T) system enhanced by phase change materials

Phase change material (PCM) is employed to enhance the thermal energy storage capacity of a building integrated photovoltaic thermal (BIPV/T) system. For this purpose, the best thickness of PCM is found using the dynamic multi-objective optimization (MOO), in which the performance throughout a year with real-time data is taken into account. In addition to the annual thermal energy storage capacity (AES), the annual energy (electricity) production (AEP), as well as payback period (PBP), the levelized cost (LCOE), and annual carbon-dioxide emission reduction (ACDR) are considered as the objective function to obtain a favorable condition from all the energy, economic, and environmental (3E) perspectives. MOO is done for a residential building in Tehran, Iran, by employing numerical modeling for system simulation and the combination of TOPSIS and NSGA-II techniques to determine the final optimal solution. According to the results, the best PCM thickness is 77.2 mm. Compared to the base condition, in which air is used as the material for energy storage, using PCM with the optimum thickness is accompanied by 22.24%, 9.93%, 17.69%, and 9.59% improvement in AES, AEP, ACDR, and LCOE, respectively. Moreover, PBP in the optimum condition is 3.321 years, which shows that utilizing the results of MOO is economically justifiable.

Utilization of on-grid photovoltaic panels to offset electricity consumption of a residential ground source heat pump

Ground source heat pump (GSHP) system is an efficient solution to mitigate energy consumption and environmental emissions in the building sector. Although the GSHP system is categorized among renewable energy technologies, considering the fact that the system's power demand is usually provided by fossil fuel resources, it may not fully meet this classification. One way to offset the GSHP's electricity consumption in a renewable approach is the use of photovoltaic (PV) panels. This paper aims to study the feasibility of a hybrid PV-GSHP system for a residential building in Tehran, Iran. To that end, a numerical model is developed to explore the GSHP system's performance over a 20-year design life, taking several borehole lengths into account. Moreover, the PV modules are simulated by EnergyPlus software. A life cycle cost analysis is also performed to assess the economic viability and optimal design of the PV-GSHP system. The results illustrate that using four PV modules can best cover the system's electricity consumption and the discounted payback period is less than four years. Furthermore, an environmental evaluation reveals that the PV-GSHP system can save 29.2 t of carbon dioxide emissions over the 20-year period compared to the GSHP system.

The design of a seasonal heat storage system with a geothermal heat pump for a residential building in Tehran

Purpose In this study, a solar water heating system along with a seasonal thermal energy storage and a heat pump is designed for a villa with an area of 192 m2 in Tehran, the capital of Iran. Design/methodology/approach According to the material and the area of the residential space, the required heating of the building was calculated manually and then the thermodynamic analysis of the system and simulation was done in MATLAB software. Finally, regarding the waste of system, an efficient solar heating system, providing all the required energy to heat the building, was obtained. Findings The surface area of the solar collector is equal to 46 m2, the capacity of the tank is about 2,850 m3, insulation thickness stands at 55 cm and the coefficient of performance in required heat pump is accounted to about 9.02. Also, according to the assessments, the maximum level of received energy by the collector in this system occurs at a maximum temperature of 68ºC. Originality/value To the best of the authors’ knowledge, in the present work, for the first time, using mathematical modeling and analyzing of the first and second laws of thermodynamics, as well as using of computational code in MATLAB software environment, the solar-assisted ground source heat pump system is simulated in a residential unit located in Tehran.

The impact of regulations on the typo-morphological transformation of residential buildings in Tehran

The typo-morphology of residential buildings in Tehran has changed tremendously from the introduction of the first building and urban regulations in the 1950s. This paper explores the role of these regulations in typo-morphological changes, how the internal arrangement and building form of residential architecture were shaped, and the nature and extent of how the layouts were influenced by building and urban regulations. A morphological and typological analysis of residential buildings was carried out and validated by in-depth interviews. The regulations with the greatest effect on typo-morphological changes include the land subdivision system, the occupancy level code, parking regulations, staircase and elevator requirements and daylight access such as patio spaces. This research also identifies issues for policy-makers to consider in any review of the building and urban regulations and their enforcement in the design process.

The impact of regulations on the typo-morphological transformation of residential buildings in Tehran

The typo-morphology of residential buildings in Tehran has changed tremendously from the introduction of the first building and urban regulations in the 1950s. This paper explores the role of these regulations in typo-morphological changes, how the internal arrangement and building form of residential architecture were shaped, and the nature and extent of how the layouts were influenced by building and urban regulations. A morphological and typological analysis of residential buildings was carried out and validated by in-depth interviews. The regulations with the greatest effect on typo-morphological changes include the land subdivision system, the occupancy level code, parking regulations, staircase and elevator requirements and daylight access such as patio spaces. This research also identifies issues for policy-makers to consider in any review of the building and urban regulations and their enforcement in the design process.

Feasibility Study of Grid-Connected PV System for Peak Demand Reduction of a Residential Building in Tehran, Iran

The use of fossil fuels for energy demand is overgrowing, leading to a higher CO2 emission. Besides, these resources have fluctuating prices and have higher operating costs. Thus, the integration of renewable energy (RE) sources has been increasing throughout the years to reduce the dependency on fossil fuel generation. However, RE generations have high initial costs and intermittent resources. Therefore, it is crucial to conduct technical and economic analysis before the installation of any hybrid energy systems. This study proposes the installation of a PV system for a residential building in Tehran, Iran. The goal of the system is to have a PV system for peak demand reduction. Moreover, the input data also includes economic parameters such as costs of PV, battery, and grid purchases alongside interest rates. Sensitivity analysis also conducted in this study to investigate the variation of load profiles on the optimal system configuration. The simulation results show a 422-kW grid-connected PV system with battery storage is the most optimal system for the selected location. The system has a lower Net Present Cost (NPC) and initial capital compared to other configurations. Moreover, the system also has a higher RE generation and lower energy import from the grid.

A sustainable multi-criteria decision making framework to select interior walls

With an increasing number of different materials, choosing the best one has become an arduous task. The vast domain of alternatives and decision criteria has led to the complexity of decision making in the conceptual phase for designers. On the other hand, due to the importance of environmental and energy concerns, considering the sustainability principles through the decision process is significantly important. Although sustainable material selection as a strategy leads to some general and main assessment criteria, identification of sub-criteria not only depends on general criteria but also pertains to the specific type of elements in buildings. Interior walls are one of those elements in construction with a complex decision making process due to their great variety of types and features. This paper aims to provide a sustainable multi-criteria decision making framework for choosing the proper interior walls in buildings. A qualitative research method using literature review, unstructured interviews and questionnaires was adopted to achieve the aims of this research. The initial data, including the criteria and sub-criteria, were collected through literature review. A framework consisting of four main components related to environmental, financial, social and technical aspects was finally developed and validated through unstructured interviews held with 23 experts in the construction industry in Iran. By dividing the main criteria into sub-criteria, in total, 23 sub-criteria were identified; to calculate their weight, questionnaires were distributed among 143 experts in the construction industry in Tehran and the analytic hierarchy process method was applied. High-rise residential buildings in Tehran were selected as a case to apply the framework, and finally the results are discussed.

An approximate method to identify torsion caused by infill walls through geometric specifications of architectural plans

A significant part of torsional effects in buildings is due to disregarding the arrangement of infill walls during the design. This is a challenging issue since on the one hand the structural engineers do not usually consider infill walls in modeling a structure, while on the other hand the architects do not pay attention to the seismic behavior of infill walls during architectural design. In this research, an approximate method for identifying the torsion caused by infill walls was proposed to be used at the final stages of basic architectural design, which is based on the geometric specifications of architectural plans and does not require structural specifications. For this purpose, through a typological study of common mid-rise residential buildings in Tehran, 20 buildings were selected, modeled, and analyzed, with 117 different layouts of infill walls, and their torsional behavior was evaluated based on criteria of seismic codes. Finally, according to the obtained results, an approximate method was developed. Evaluation of this method on the analyzed models showed that 96% of them with a risk of torsion were identifiable by this method, and in 98% of models the results were reliable, so the proposed method has a high degree of accuracy.

Optimization and energy-economic assessment of a geothermal heat pump system

The high geothermal heat exchanger (GHE) installation cost is the main challenge encountered in the widespread use of geothermal heat pump (GHP) systems, so its optimization is vital for reducing the costs. In the present study, five main parameters ─the radius, length, and the number of wells, the external pipe's radius, and the flow discharge inside the pipe─ are optimized by genetic algorithm (GA) for a residential building in Tehran. Moreover, sensitivity analysis of several design parameters, which are not considered in the objective function, indicates that pipe thermal conductivity, borehole thermal conductivity, soil thermal conductivity, and borehole distance parameters had the highest effects on entropy generation (EG), respectively. Therefore, this approach can help engineers to select the most efficient parameters for improving their design. Eventually, the optimized GHP is investigated by energy and economic viewpoints. One-year energy simulation of these systems is conducted to determine the energy consumption. Simulation results suggest that the annual energy consumption of the GHP with the coefficient of performance (COP) of 5.6 is 10.111 MWh; whereas, the annual consumption of heat pumps with an air-source heat pump equals 42.222 MWh, which is 4.17 times greater than that of the GHP. A simulation over a 10-year period is also performed to consider the drop in performance of the GHE over time. Furthermore, the economic analysis results suggest that the payback period of this system is about 7.4 years, and the energy subsidy paid by the government will be reduced annually to 14, 417, 839 Iranian Rial (IRR).

Multi-objective optimization of cooling and heating loads in residential buildings integrated with phase change materials using the artificial neural network and genetic algorithm

Abstract In this paper, a multi-objective optimization was performed to achieve the minimum cooling and heating loads in a residential building integrated with phase change material (PCM). The methods applied to fulfill this objective were numerical modeling by EnergyPlus, Grouped Method of Data Handling (GMDH) type of Artificial Neural Network (ANN) and Non-Dominated Sorting Genetic Algorithm II (NSGA-II). In this study, design variables were melting temperature and thickness of PCM, thermal resistance of exterior walls, internal gain and infiltration rate. Additionally, objective functions included annual cooling and heating loads of the building that should be minimized. Therefore, first, EnergyPlus software was used to calculate the values of objective functions and to train the neural network. Afterward, the GMDH-type neural network was applied to derive polynomials computing the objective functions from input variables. Then, Pareto optimal points for objective functions were obtained through using these polynomials and NSGA-II multi-objective optimization. Finally, the optimum point was determined by a financial analysis. According to the obtained results, the thickness and melting temperature of the optimum PCM layer in the residential building in Tehran were equal to 0.032 m and 24.58°C, respectively.

A decision-making framework opted for smart building's equipment based on energy consumption and cost trade-off using BIM and MIS

Development of Building Information Modelling (BIM) is assisting engineers with automating design/construction processes in the Architectural, Engineering and Construction (AEC) industry. Lack of such a comprehensive decision-making framework which utilizes BIM, Management Information Systems (MIS), simulation, and automation tools to choose between different construction alternatives have been addressed in the research background. As an example of decision-making objective, optimized smart building's equipment combination for a certain project should be selected in the feasibility study phase. In this research, a comprehensive decision-making framework was developed to choose smart building's equipment based on energy consumption and cost trade-off. Subsequently, smart building alternatives were considered as a decision-making example to choose the best alternative using BIM, MIS and simulation tools. The research contributes to the automating of some parts of the decision-making framework by developing an Application Programming Interface (API). This API helps with making the appropriate automating permutation out of possible options, totalizing the cost of each combination and sorting data in the research database developed for the recommended framework. This framework, database and API can be used similarly for any other decision making objective. Finally, a model representing the average conditions of residential buildings in Tehran was developed to choose the optimized smart building's equipment combination of 31 considered options. This optimized combination which included all possible smart building options except for smart lighting has an investment return of about 7.5 years which is more than that of similar projects in other countries due to Iran's low energy carrier tariff.