جستجوی مقالات مرتبط با کلیدواژه "بهینه سازی مصرف انرژی" در نشریات گروه "مکانیک"

 Currently, countries are paying more attention to the issue of energy and trying to reduce its consumption. Since buildings are one of the largest consumers of energy in the world, so optimizing and saving energy consumption in this sector is essential. In this study, with the aim of selecting the optimal materials in energy consumption, the effect of materials on energy consumption in educational buildings in Tehran was investigated. In order to achieve this important goal, 6 buildings with the same architecture, 2 types of structural materials and 3 different types of insulation in external walls Was simulated with Design Builder software. According to the simulation results, buildings made of exterior brick wall materials consume less energy than concrete block walls in similar conditions. Also, in the three types of insulation studied in this research, the use of silicone insulation has the highest energy consumption and fiberglass insulation has been the most optimal material in terms of energy consumption. Insulation of phase change materials is in the middle. This insulation has a better performance in terms of energy consumption than silicon, but it has a higher energy consumption than fiberglass insulation. According to the mentioned results, it is suggested to use a building with a brick wall and fiberglass insulation for an educational building in the climate of Tehran in order to reduce energy consumption and optimize it.

Nowadays different kind of active and passive methods used in order to reduce energy consumption and air pollution in buildings. Simultaneous use of phase-change material (PCM) and green roofs with triple-skin facades (TSF) and triple glazed windows (TGW) in residential buildings equipped with Building-integrated photovoltaics (BIPV) can lead to 70% annual energy saving. On the other hand, PCM type and applying methods in different climate conditions impacts energy saving in these conditions. So for the first time, in this research Multi objective optimization of a residential buildings equipped with above technologies was done by the help of genetic algorithm. Reduction of required heating and cooling loads was chosen as optimization’s objectives and three climate conditions of Iran was selected. Results indicate that maximum energy saving is 73.3%. Maximum Cooling load reduction is 92.2% which is happened in biome-dry tropical climate conditions. In addition, Maximum reduce in Co2 emission is 60.6% for Tehran.

With the rising number of swimming pools and their users, the amount of energy consumption in the pools has increased significantly. In addition to the negative environmental effects, this issue causes high costs associated with high levels of energy consumption. Therefore, the main goal of this research is to provide solutions for sustainable management of energy consumption in swimming pools. Following analysis of the primary data for this research gathered through semi-structured interviews, a number of solutions are developed for sustainable management of energy consumption in swimming pools. These solutions encompass 6 main themes, namely water, temperature, light, air, materials, monitoring and inspection, which in themselves contain 73 sub-themes. Some of the solutions identified in the research include: using anti-evaporation covers, passive heating of the pool using solar energy, adding thermal insulation to the floor of the pool, using energy-saving underwater lights, using natural light to reduce dependency on artificial lighting, using insulated coatings in materials and equipment, using thermal recycling systems, optimizing air filtration systems, replacing old equipment with new ones and continuously monitoring key water parameters such as PH, chlorine, organic matter, and the amount of microbial density.

As the main factor of countries' economic development, which are also needed by all generations. In recent years, the issue of energy supply has been one of the significant challenges, the main reason for which is dependence to the limited supply of fuel. The way to end this problem seems to optimize energy consumption and re-switch to renewable energy. In this research, a building in the new city of Andisheh is analyzed considering environmental conditions and geographical directions using Carrier air conditioning software, and its thermal and cooling loads are examined for two different compositions of external walls. After selecting the optimal mode, the building is rotated 45 degrees clockwise, which by examining eight different directions, the minimum and maximum heating load required are equal to 124502.8 and 129579.3 kcal per hour and its cooling load were equal to 53.53 and 55.44 tons of cooling, respectively. In the second step, in order to use renewable energy considering the average daily radiation of 5.2 kWh in the new city of Andisheh, the project of hot water consumption using solar energy led to savings of 18945.16 Cubic meters of natural gas per year. The economic study of this issue shows that the return on investment of solar water heaters is 11.26 years, which is not cost-effective in the current economic situation.

This study used the finite volume method and ANSYS software to investigate the effect of elbow air duct vane structures on its performance. Elbow air ducts are among the most widely used ducts in HVAC systems, and changes in their geometry and structure have a significant impact on their performance. The purpose of this study is to investigate changes in the structure of elbow air duct vanes from simple to several different models. These changes include zigzag, semicircular, and sinusoidal vanes with different sizes and pitches, comparing them with a simple vane. Therefore, changes in the temperature, velocity and pressure fields of the air flow in the elbow duct are evaluated. The results of this research show that using zigzag vanes, with smaller pitches, whose lateral ends are facing downwards, causes more disturbance in the air flow in the elbow duct, and increases the heat transfer with the environment. The vane edge tips also had an impact on the amount of disturbance. Also, using sinusoidal vanes has reduced the pressure on the outer radial wall of the elbow air duct. So that, respectively, the use of sinusoidal and simple straight vanes created the lowest and highest pressure levels for the outer wall of the elbow air duct

Due to the importance of natural phenomena in human life, investigation and study of these phenomena has always been of interest. The aim of this study is to investigate the stack effect that occurs in all buildings, although it is more noticeable in high-rise buildings. Due to the importance of this phenomenon in the energy consumption of high-rise buildings, in this research, these types of buildings have been studied. Due to the importance of the influence of the cross-section of buildings on the occurrence and behavior of this phenomenon, therefore, elliptical, triangular and rectangular cross-sections with the same surface have been examined and by comparing the results, different cross-sections have been evaluated and compared. The simulation of this phenomenon has been done in Fluent software and the analytical results have been compared, which shows a good match. The results show that the elliptical cross-section, according to its geometry and aerodynamic conditions, has the best performance in terms of the amount of additional pressure required to create positive pressure and energy consumption.

Saving energy is one of the most important challenges in the world today. In recent years, growing concerns about the environmental consequences of energy consumption and global warming have doubled in importance. On the other hand, the share of the construction sector in the energy consumption of countries is significant and for this reason, in recent decades, in most industrialized countries, basic measures have been taken to improve consumption patterns, using various tools such as regulations. One of the most important energy consumed is electrical energy, which is one of the most basic energy sources of buildings and plays an important role. The complex problems and processes of electricity generation and transmission, the pollution generated by the production of fossil fuels, and other cases have prompted researchers to seek solutions to reduce energy consumption or, in other words, optimize energy consumption. In this study, some practical solutions to move towards energy saving have been investigated and the effect of using materials with different heat transfer coefficients in external walls according to Semnan weather conditions on the modeled building and to analyze the cooling and heating load of the building. Compared with renewable materials. Finally, the external wall, using a 20 cm straw block, has reduced the annual energy consumption compared to perforated pottery, autoclaved concrete, and Article 19 of the National Regulations has resulted in 3%, 0.6%, and 2.76%, respectively.

In conventional passenger cars, two-third of the energy is wasted from the exhaust gas and engine cooling system. The present study has investigated the performance of a waste heat recovery (WHR) system based on the Organic Rankine Cycle (ORC) for the turbocharged gasoline direct injection engine. The optimal working conditions along with the best working fluid of the organic Rankin cycle to obtain the maximum net output power (NOP) from the recovery cycle are investigated. The steady-state zero-dimensional thermodynamic model of basic ORC at a series of engine operating conditions is designed in Thermoflex software. The working point of the engine has obtained by simulation of vehicle performance based on the standard urban driving cycle. Considering numerous and varied working fluids, 23 working fluids including pure and mixture fluids are evaluated. The mass flow rate of working fluid, condenser pinch, turbine inlet pressure, and condenser working pressure are considered as the optimization design variables and the optimum operating conditions of the basic ORC extracted for each working fluid using the Downhill Simplex method. Finally, by having experimental data for 320 points of the engines map, the efficiency of the optimized basic cycle was analyzed in combination with engine’s entire operating region. The results showed that R-507a, R-410a and R-125 present highest NOP respectively which indicate better performance of zeotropic and Azeotropic mixtures in engine WHR by ORC and for the best case, NOP reached to 2.6 kw in small load region and 6.6 kw in the peak thermal efficiency region.

One of the most important issues in the world today is energy saving, which in the construction industry, proper thermal insulation is one of the solutions to prevent energy loss. Also, the use of new and suitable insulation materials helps us to achieve this. Energy crisis, global warming and other environmental issues have always been the main motivation for researchers and engineers to look for new ways to reduce building energy consumption. Recently, the use of phase change materials to increase the thermal mass of the building has received much attention. Phase changers are organic or inorganic compounds that have the ability to absorb and store large amounts of heat energy within themselves. Due to this unique feature, using these materials can naturally delay the transfer of heat to the building for several hours during peak hours of energy consumption and therefore closer to the goal of optimizing energy consumption in the building. The use of phase change materials in the construction industry along with the proper use of the capabilities and physical properties of materials, was introduced in the world several decades ago and is now known in developed countries, while in our country the research and application of these materials in the construction industry remains almost unknown. The purpose of this article is to introduce and provide suggestions for using phase change materials to store and reduce energy consumption in the building.

In this article, technical-economical investigation of heating and cooling loads in faculty of engineering of Arak university, Iran has been investigated. The tradiational and modern conditioner systems such as CAV, VAV, fan coil systems (all three systems are tested with direct fired absorption chiller and screw chiller), VRF system, split system and evaporative cooling system (in total 9 different systems) are designed for this faculty and are compared technically-economically. In this article, the costs of water, electricity and gas, purchase of systems and equipment, maintenance and repair of equipment of the examined systems are calculated and are compared with each other and then this work is done in different cooling loads, so that the results are not limited to the technical faculty of Arak university and can be used for all existing systems throughout the country. In the end, it is shown, that the evaporative cooling system has the lowest current and initial cost among the other systems. however, since this systems do not have the ability to determination of the amount of humidity and ideal temperature for the desired space can not be considered as an ideal and standard system. Also it is shown, that the current and initial costs of compression chiller are less than of absorption chiller and VAV systems have the better performance than CAV and fan coil systems, and the VRF system, after the evaporative cooling system, has the lowest current and initial cost among the examined systems, especially the split system. Due to the intelligent and optimal control of this system, it can be selected as an ideal system.

Present paper introduces a novel floor heating system which provides its heat by the Sun. This integrated system incorporates the advantages of both floor heating and free energy supply simultaneously. It is examined for a special building under different climate conditions. Based on the obtained results for very cold climate conditions the new system’s performance is significantly low. This is mainly due to the working fluid’s high temperature limit which causes the supporting solar system to be too much bigger than the normal one which is sufficient to heat up the building. The most significant advantages of the proposed design is for moderate climate conditions where the inlet temperature limit does not impose an extra area and, hence, cost for the solar system. For this condition the integrated system has superior advantages to the traditional ones.

In today's world, the national security of most countries has depended on secure energy access, and therefore the optimum use of it has been the focus of attention of many statesmen and researchers. Expansion of consumption in the household sector and waste of energy in the urban community are among the obvious reasons for the rapid growth of energy consumption in the national economy. For this reason, energy consumption in the building sector needs to be considered. In this paper, after simulating an office building in Garmsar City with Design-Builder Software and validating it, the effect of the roof insulation and double wall parameters on the energy consumption has been investigated. The results show that the roof insulation and the use of a double wall can have a significant impact on building energy consumption.

In this study, the effects on energy optimization in cold and mountainous atrium examined. Three atrium in the shape of a cube, flat and domed have been simulated. Designed with the length and width dimensions (30 m × 30 m) and a height of 7 meters in the center of each of the models in order to form a flat atrium dimension (14/30 × 13/80) square and cube size meters and height (3/50) meter radius dome shape (7) meters in height (7 meters) were studied. Simulations of these models in three modes of ventilation (0, 30, 70) percent during the coldest week of the year, from the date (30 January - 6 February) that the outside temperature (-0.69 to 10.64 °C) below zero and also during the hottest week of the year to date (22 July - 28 August) that the outside temperature (25.78 to 30.70 °C) is investigated. Numerical simulation results show that the optimal shapes of the dome-shaped atrium with natural ventilation are 30%. A field sample (experimental) atrium as a validation were studied. Compare the numerical and experimental results show that the numerical simulation accuracy is very good with experimental.

The main cause of the energy dissipation in buildings in the country, in addition to design style of employment in the town of Bad materials in different parts of the building. It can be simple solutions to the implementation of some of the loss of a significant amount of renewable energy. In this study , optimize energy consumption in an administrative building in Semnan province climate in a bid to replace the window glass - with the designated low dispatch in foreign wall instead of single - walled window with the situation by simulator design builder software was investigated. Results of energy - saving by 12 percent annually in the coolant load, 2 percent in heating load and 11 percent of the total sample building in loads.

The contribution of the building sector to the energy consumption of countries is significant, so in the last few decades, in most industrialized countries, basic measures have been taken to reform the consumption model , using various tools including regulations and criteria . In this study, the use of the type of material used in the walls of the city buildings in the Garmsar city building was analyzed. The comparison of the heat transfer coefficient of each material used on the external walls of the building is modeled and the building is evaluated with basic materials according to the climatic conditions of the city. Finally, using new materials in the outer wall and ceiling, building with double wall is a priority in reducing energy consumption.

In this paper, the problem of optimal distillation columns sequence determination for a multicomponent distillation system with heat integration between condensers and reboilers of various columns with using mathematical programming approach considered. Existence of nonlinear constraints also discrete and continuous variables in optimization model is reason that the problem will be a Mixed-Integer-Non-Linear-Program (MINLP). MINLP model that obtained from mathematical programming is solved with GAMS. Some of proposed method features are generality and flexibility for defining new operating conditions. In proposed MINLP model, the effect of heat integration on optimal sequence has been considered by simultaneous optimization of sequencing and energy demand. Energy saving using heat integration has become possible by regarding column pressure as a variable in optimization model. The Results obtained from solution of MINLP model for a four components separation, shows 25% saving in total annual cost that includes investment, operation costs and energy consumption. . .

One of the recently considered applications of fiber optic, in their usage in building lighting systems. In this research, in order to reduce energy consumption, by transmission of sun light from the roof to the desired place (i.e. an office), the required standard luminance is produced. The main aims of this research are :1. Reduction of energy consumption.
2. Making the place compatible with the human favorable mental conditions and environment.
3. Preparing the basics of mass production of the system and economical benefits for the university
In this research besides concentrating the sun light to magnify its density, some investigations are made for light transmission by fiber optics, because, no mathematical model was found for this per pose, practical tests are made in addition to statistical analysis.
Using different lenses and fiber optics and a position control system (which specially designed for this research), many experiences were made and iluminances were measured by a lux meter. After that by SPSS V.17 software, the results were analyzed. Finally the best Lenz and fiber were selected and a straight forward method was presented for designing a typical office in such manner.

One of the recently considered applications of fiber optic, in their usage in building lighting systems. In this research, in order to reduce energy consumption, by transmission of sun light from the roof to the desired place (i.e. an office), the required standard luminance is produced. The main aims of this research are :1. Reduction of energy consumption.
2. Making the place compatible with the human favorable mental conditions and environment.
3. Preparing the basics of mass production of the system and economical benefits for the university
In this research besides concentrating the sun light to magnify its density, some investigations are made for light transmission by fiber optics, because, no mathematical model was found for this per pose, practical tests are made in addition to statistical analysis.
Using different lenses and fiber optics and a position control system (which specially designed for this research), many experiences were made and iluminances were measured by a lux meter. After that by SPSS V.17 software, the results were analyzed. Finally the best Lenz and fiber were selected and a straight forward method was presented for designing a typical office in such manner .

Energy consumption is one of the most important factors that reveals development situation of the countries. Management and optimization of energy consumption due to both conservation of energy resources and reduction of environmental pollution is also very important. In Iran Among the four major sectors of industry, agriculture, construction and transportation, energy consumption of buildings with the highest consumption accounted for about 42 percent. In this paper in order to optimize energy consumption, the impact of changes in effective parameters on heating and cooling load of buildings in the consumption and cost of electricity and fuel has been studied by HAP Carrier software. According to simulation results, the costs of electricity and fuel to the building by taking steps such as changing the internal design temperature within one degree Celsius, 7.7 and 3.4 percent , lower infiltration rate to zero, 2.6 and 18.6 percent, the use of 10 cm thick polystyrene insulation in roof and exterior walls, 4.5 and 15.3 percent, change from single-glazed windows to double with vinyl frame, 5.8 and 6.8 percent, using 20 cm thick leca blocks instead of 10.5 cm thick solid brick, 3.9 and 11.9 percent has been reduced. Also, reducing hot water output temperature from package to 10 degree Celsius reduces gas costs to 11.9 percent. The most appropriate orientation for achieving the lowest cost of electricity and fuel is when the biggest wall towards the north, use the package system and radiator and evaporative cooler would lower the cost of electricity and fuel as well. In addition, the simultaneous application of all proceedings, the annual cost of electricity and fuel is reduced to 21.1 and 40.7 % respectively.