جستجوی مقالات مرتبط با کلیدواژه "economic analysis" در نشریات گروه "مکانیک"

The economic model generally expresses the mechanisms used to earn money from a business, and if it doesnot generate income, its failure will be certain. Therefore, the decision to carry out a mission isnot only based on technical specifications, and besides that, economic profitability is another part of decision-making and will be one of the main factors for commercial investments. Space projects, as wellas moon-mining projects, are no exception to this rule and require an all-round approach to compare financial and technical feasibility. Analyzing the economic feasibility of any project can be summed up in the evaluation of its economic model. In this regard, a model is needed to compare, rank and determine the available options, which is economically justified. In this paper, the economic evaluation of moon-mining based on the materials available on the moon and sending them to the earth is discussed. Materials with economic priority are categorized and selected in a fuzzy evaluation and using an economic model suitable for space mining, an economic evaluation for the business of selling materials on the Earth is carried out and according to economic efficiency, the type of material and also the high-level specifications of the project has been extracted.

Liquid hydrogen is a solution for storing and transmitting electricity that is produced by renewable energy sources such as geothermal energy. In this paper, a Rankine cycle with a proton exchange membrane electrolyzer, an ammonia absorption refrigeration cycle, and a hydrogen liquefaction cycle are simulated and analyzed for storing geothermal energy as liquid hydrogen. The power generated by the Rankine cycle is used to produce hydrogen gas in the electrolyzer. Additionally, the cooling obtained from the absorption refrigeration cycle is used to pre-cool the hydrogen gas to a temperature of -9.26 ℃, and then the hydrogen is liquefied at -253 ℃ by a mixed refrigeration cycle. The innovation of this study is based on using the cold energy obtained from the absorption refrigeration cycle in the liquid hydrogen production cycle and integrating the liquid hydrogen production process with the geothermal energy system. By using energy, exergy, and economic analysis, the final cycle efficiency was improved compared to the initial system. The special energy consumption of the liquefaction unit is 81.8 kWh per kilogram of hydrogen. In a three-year payback period, using economic analysis, the minimum selling price is calculated to be $2.11, which is lower than a similar liquid hydrogen production cycle presented in the past.

Water plays an important role in human life and is one of the first human needs for survival. Therefore, due to population growth and industrialization and therefore the lack of water resources in the world especially in Iran, its supply needs special attention. Currently, 97.5% of the water resources on the planet cannot be used. The main purpose of this study is the economic study of the use of fixed and floating freshwater in Makran beaches. One of the most important methods in this field is the desalination and desalination processes of seawater. Given that for government projects, only the final price or in other words the cost price is considered, the method of levelized cost of production over the useful life has been chosen. According to the information of the Electricity and Energy Master Planning Office of the Ministry of Energy, the results show that the desalination of seawater in the form of building a factory (fixed desalination plant) is more economical compared to the floating desalination plant, in such a way that the levelized cost of production in fixed desalination technology is 2000 and in floating desalination technology is 9700 rials per cubic meter. Also, sensitivity analysis tests based on the discount rate, production capacity coefficient, and escalation rate of fuel cost show that on one hand, floating desalination technology is more sensitive to the above variables than fixed desalination, and on the other hand, the change of this variable has no effect on changing the economic priority. The results show that seawater desalination in the form of a factory (fixed desalination) is economical compared to floating desalination.

In this paper, a new system is proposed for the hydrogen liquefaction based on geothermal energy, in which, the nitrogen is first converted to liquid, and then, is used as to temperature decrease the gas hydrogen, in the hydrogen liquefaction cycle. This system includes four sub-systems; an Organic Rankine Cycle (ORC), an ammonia-water absorption chiller, and two Claude cycles for hydrogen and nitrogen liquefaction. The geothermal fluid at a temperature of 200 ℃ and a mass flow rate of 100 kg/s is considered as the energy source of the system. The proposed system is assessed from the thermodynamics and economic viewpoints. Then, the effects of the compressor outlet pressure, the geothermal fluid inlet temperature, the evaporator temperature, and the generator temperature on the exergy efficiency, the cost of the produced liquid hydrogen, and the hydrogen liquefaction ratio are investigated through a parametric study. Also, increasing the compressor outlet pressure increases the power consumption of the system. Also, at the geothermal fluid temperature of 430 K, the exergy efficiency of the system is determined as 69%. Moreover, the results of the economic analysis show that the production cost of 6.629 (kg/s) liquid hydrogen will be 1.39 $/kg (7.79 $/GJ).

In the present study, two proposed designs for compressed air storage systems, one equipped with heat recovery and the other without it, are presented and their technical analysis is performed. The costs of each project are evaluated and economic analysis including Net Present Value (NPV), Internal Rate of Return (IRR), Profitability Index (PI), and Discounted Payback Period (DPBP) is performed. These analyses are presented for storage energy values of 80, 220, 360, 480, 640, and 1000 kWh and storage pressures of 50, 100, 150, 200, 250, 300, 350, 400, and 450 bar. The results of the technical and economic analysis show that these systems are more justifiable to produce higher capacities at lower storage pressures. Finally, using the results of this analysis, the optimal energy storage plan of 640 kWh with storage pressure of 50 bar is proposed. The results of this study can be used to select a suitable compressed air storage system for peak shaving during peak hours of power consumption.

The increasing energy demand in industrial and operational units and corresponding concerns about the limited fossil resources as well as environmental pollutions urge the researchers to generate electricity from renewable energy sources such as wind, geothermal, solar, and biofuels. In the present work, the use of solar and geothermal energy in producing electricity is investigated. The proposed cycle is capable of producing power by using both solar and geothermal energy sources simultaneously or can be used separately to generate electricity. Organic Rankine Cycles (ORCs), which benefit working fluids like refrigerants, have been employed. These cycles are able to produce electricity from low-temperature energy sources. The cycle is designed to employ two evaporators as high temperature and low temperature ones and, consequently, is equipped with two turbines as high and medium pressure ones. The governing equations of mass balance and first and second laws of thermodynamics were applied to each cycle component. A numerical code is written and solved by EES software. The performance of the proposed cycle was analyzed by energy and exergy viewpoints and the first and second law efficiencies were calculated. Therefore, the amount of exergy destruction and exergy efficiency of each component was defined. To evaluate the cost of the final product, which is electricity, exergoeconomic analysis, as an efficient tool, was carried out and the final cost of products was defined. Parametric study of the effect of different designing parameters, such as pinch point temperature difference and evaporator temperature on the energy and exergy performance and cost of the product was done. The obtained results showed that the best second law efficiency was related to high-pressure turbine, whereas the low-pressure turbine acquires the highest value of exergoeconimc factor. The average electricity production cost based on power generation in low- and high-pressure turbines was calculated as (0.102$/kwh).

Increased demand for fossil fuels has led to climate change, global warming, and declining energy reserves. The use of renewable energy, such as solar energy, is a suitable approach to generating electricity and heat. One of the common systems in using solar energy is parabolic collectors, which enable this clean energy by converting the incoming radiation into thermal energy. In the present paper, to assess the potential of climates to make optimal use of solar parabolic collectors, a numerical model was developed in MATLAB software. Then, while validating the model with existing experimental results, the effect of climate change has been studied in four areas: energy, exergy, economy, and environment. For this purpose, five cities: Rasht, Shiraz, Tehran, Abadan, and Sanandaj, have been selected as representatives of Iran's climate and energy efficiency and exergy, the unit cost of energy, and the amount of carbon dioxide produced during the life cycle of the system has been obtained. The results show that Shiraz, with a  Semi-Arid Cool climate and thermal efficiency of 72% and a unit cost of  0. 035 $/ kWh, is the optimal climate in the fields of energy and economy, and Sanandaj with a Humid Continental climate and exergy efficiency of 17. 7% is the optimal climate in the field of exergy. In the environment, Rasht, with a Humid Subtropical Climate, was introduced as the optimal climate.

Thermal Energy Storage (TES) is a high potential technology for different thermal energy applications. TES technology can be an appropriate approach to fill in the gap between electrical energy supply and demand. One efficient and modern method to store thermal energy is the use of phase-change materials (PCMs). The aim of this research is to study the feasibility of the use of PCM materials in the combination of free cooling and compression refrigeration systems. The combined system should be analyzed from energy and exergy viewpoints, in order to evaluate the amount of saved energy and the system performance upgrade. The medium temperature PCM coupled with the free cooling system, can be charged during the cool night time. During the hot day time, discharging this PCM would lower the temperature of the air entering the condenser and consequently; lower the HVAC system energy consumption. On the other hand, PCM discharge happens during the peak-hours in which the electrical energy price is high. Therefore, using PCM would reduce the building energy bills. Technical and economic results show that the proposed combined system would reduce the total electrical energy consumption up to 4.85%, energy consumption in peak-hours up to 14.76% and the electrical energy bill up to 6.71%.

The increasing consumption of non-renewable energy sources such as oil and gas and reducing their reserves make it more necessary to pay attention to clean and renewable resources. In this situation, wind energy is known as one of the safest options for generating electrical energy. In this study, with the aim of evaluating the impact of climate change on the economic and environmental characteristics of wind turbines, numerical modeling was developed in MATLAB software. In order to evaluate the effects of the mentioned parameters as a case study, this numerical modeling for the parameters expressed in 4 cities of Iran, including Rasht, Tehran, Abadan, and Sanandaj, as the representatives of the main climates of Iran has been analyzed. According to the results of the economic point of view, which represents the Levelized cost of the energy production unit, Abadan was recognized as the most economical case with a   Levelized cost of  1.04 $ per kilowatt-hour of energy. Also, the environmental aspect of the analysis, which is based on the life cycle assessment method, considering the amount of carbon dioxide produced during the system life cycle and its pricing based on penalty policies, Rasht with a mild climate and emissions of 156 kg. Carbon dioxide per year and the lowest fine cost (annual cost $ 2.26) showed the most suitable option among other cities.

Iran is using natural gas as the main energy carrier in many sectors. Establishing peak-shaving liquefaction units due to reduction in volume of natural gas, is the most desirable way to store surplus natural gas in the warm seasons and using it in cold seasons of the year. Due to the high cost of operating and maintenance of liquefaction cycles, inventing solutions aimed at reducing energy consumption and improving the economy of these units, is really important. In this research, along with selecting Shahid Rajaee power plant in Qazvin as case study, the natural gas liquefaction cycle with mixed refrigerant and absorption refrigeration pre-cooling with the purpose of supplying the fuel of total unit of this power plant for 60 days was established. Then, it was subjected to technical and economic analysis and in terms of operational parameters was compared with common single mixed refrigerant cycle (without precooling). Results show that in comparison to common single mixed refrigerant cycle the specific power consumption %43, the cost of liquefaction plant equipment %15, the flow rate of mixed refrigerant %69 decreased and the figure of merit %28.36 increased.

In this study, the energy, exergy and economic analysis of a solar tower considering environmental conditions in several cities of Iran is presented and suggested a strategy for choosing the city to achieve the best performance and lowest cost in using the solar tower. The cost function consists of the costs of the mirror area, the tower height, and the equipment inside the central receiver aperture. The thermal and economic modeling of the solar tower is done and the amount of heat required to the receiver, the area of the required mirror and the cost function is calculated for six months in one year to reach a capacity of 6 MW. The cities of Tabriz, Arak, Shiraz, Semnan, Ahvaz, Birjand, Yazd, Kerman and Isfahan are selected for the investigations. Wind speed, DNI, and ambient temperature for each city in different months are considered. The results show that the highest energy efficiency is Shiraz (91.42%)and highest exergy efficiency belonging to the city of Tabriz and Arak city (56.56%). Economic analysis shows the highest cost of a solar tower is for the cost of the mirrors, tower height and receiver cost, respectively. The lowest cost function, as well as the required mirror surface (20898 m2), is for the city of Shiraz. Based on the TOPSIS making decision method for using a solar tower, Kerman (with a score of 0.1508), Shiraz(with a score of 0.1378) and Isfahan(with a score of 0.1276) are in the first, second and third places, respectively.

In this paper, an integrated combined cycle power plant structure and thermal water desalination system have been developed. The integrated design has the capacity of producing 188.6 MW power, 34.77 kg/s fresh water and 94.57 kg/s liquid carbon dioxide. In order to supply the input heat to combined cycle power plant and thermal water desalination, heat recovery operations are carried out on the out flow of the oxy-fuel power plant and solar collector cycle. Also, in order to provide cooling of the air separation unit and natural gas used in the integrated structure, the operation of converting liquefied natural gas (LNG) to natural gas is used. In the integrated structure, the overall thermal energy efficiency is 75.83% and total exergy efficiency is 93.67%, respectively. The total thermal energy efficiency is 13.62% and the total exergy efficiency is 34.55% higher than the integrated structure developed compared to other similar structures in this paper. The period of return is 2.282 years and prime cost of freshwater product is 0.2269 US$/m3.

In gas power plants, a lot of energy is lost in the form of heat more than the electricity produced. In the present research, techno-economic evaluation of combined power, desalination and cooling systems running by the exhaust flue gases of a gas turbine in Iran is performed. In addition to using power generated by the gas turbine, attempts were made to use Organic Rankine Cycle to recover the heat dissipated from gas turbine in order to reproduce power. In fact, choosing the appropriate technology for the combined system of simultaneous production of power, fresh water and cooling based on energy and economic analysis is investigated. Results showed that multiple-effect distillation system with fresh water price of 1 $ per m3 should be used in order to produce high tonnage fresh water, and to achieve the proper price of fresh water, Reverse Osmosis by giving priority to ORC power, and then, GT application is suggested. According to the calculated price of power sale, the sale of gas turbine power is approximately 0.1 $ per kW/h. Regarding cooling systems, the results showed that the absorption system has a lower initial cost and produces a greater cooling load than the compression system, and if necessary, the compression cooling system can be used only to achieve very low temperatures.

In this research, optimization of gas microturbine through economic, exergy and environmental analysis has been investigated by the gray wolf algorithm. First, a thermodynamic modeling was performed for each of the above modes, and then using the gray wolf method, optimum points were determined for each system's performance. For modeling, the code written in MATLAB software was used. The results of the study showed that the increase in maximum temperature has a small effect on the increase in the cost of purchasing and installing and maintaining equipment on the micro turbine cycle, which indicates that increasing the combustion temperature to the extent that the metallurgical limit of the cycle allows us to be a good factor in increasing the cycle efficiency with Considering economic issues. As well as increasing the efficiency of the recuperator, the greatest cost is borne by other factors on micro turbines. As the compressor compressor ratio increases, the cost of fuel is increased as shown above. The effect of increasing the turbine input temperature on the cost of exergy damage and the total cost of consuming fuel and purchasing, installation, and maintenance, as well as the matching of input data with the model derived from the gray wolf algorithm related to the total purchase, installation, and maintenance costs In addition, the cost of exergy damage plus fuel consumption is shown.

Due to the increasing costs of energy and reducing fossil fuel, the use of renewable energy is more important. In this study, the possibility of using hybrid energy systems was evaluated to supply electricity to an animal husbandry unit in Mianeh City. For this purpose, three sources including wind turbine, photovoltaics and diesel generator were evaluated in terms of environmental, technical, and economic. This evaluation was performed by Homer Energy Analysis Software, and the results demonstrated that diesel generator is the least expensive solution in compared to other conditions. Then, analysis of the results showed that hybrids of diesel generator-photovoltaic, wind turbine-diesel generator, and diesel generator-photovoltaics-wind turbine systems have low cost, respectively. But environmental results depicted that the use of triple hybrid system in condition of 38% diesel generator, 51% photovoltaic and 11% wind turbine, has lowest emissions, so that carbon dioxide emissions were reduced by 38.4% compared to single diesel. Considering the capital return index, which is a key indicator in the design of feasibility studies, the time of capital return for using a diesel generator was obtained more than three years and seven months. While this index in the condition of using diesel generator-photovoltaic was obtained less than a year, in this respect, this condition was in the first rank.