جستجوی مقالات مرتبط با کلیدواژه « چرخه ی رانکین آلی » در نشریات گروه « فنی و مهندسی »

The use of geothermal energy is expanding worldwide due to its durability, environmental benefits and high power production. One of the most common types of geothermal systems is the Double Flash (DF) cycle. Typically, a significant amount of energy is lost through the saturated liquid of the second separator in this configuration. With the approach of using this energy, a DF–Organic Rankine Cycle (ORC), a novel DF–CO2 Transcritical Rankine Cycle (CTRC) and a novel DF–ORC–CTRC are investigated from energy and exergy viewpoints. Then, for configurations, a comprehensive parameter analysis and single-objective optimization were performed for configurations with the criterion of net output power maximization. The results indicated that all three combined configurations outperformed the double flash cycle in terms of the first and second laws of thermodynamics. Among the investigated cycles, the DF–ORC–CTRC demonstrated the best performance, with net output power, energy efficiency, and exergy efficiency calculated as 26313 kW, 20.54%, and 64.46%, respectively.

In this study, a new cycle of cogeneration power, heating and cooling integrated with fresh water production system by multi-effect desalination method and solar system has been evaluated. Energy and exergy analyzes have been used to evaluate system performance. In order to generate power, the gas cycle has been used as the main stimulus and the organic Rankin cycle has been used as the downstream cycle. The results of this study show that due to the addition of the solar system in the vicinity of the organic Rankin cycle, the increase of the organic Rankin cycle efficiency improves from 38.778% to 44.592% to 5.813%. In addition, at constant cooling rates, the cooling performance increased by 1.275 percent from 1,596 to 1,617. Also, due to the high production capacity of the gas turbine cycle compared to the production capacity of the Rankin cycle, the addition of the solar system to the base cycle (without the solar system) increases the thermal efficiency and exergy by 0.638 and 0.085%, respectively. Also, distillate flow rate increases 726.8 Ton/h by using reverse osmosis system.

In the last years, hydrogen production not only as a green fuel but also as an energy career has gained much attention. This is while, hydrogen can be considered as one of the main chains of alternative fuel production like green methanol and green ammonia. In this study, the waste heat of the offshore installed gas turbines is utilized to produce hydrogen via employing Alkaline electrolyzers. In most cases, gas turbines are installed to cover the electricity consumption of the offshore facilities and waste heat recovery from these turbines is not a matter of concern. In this paper, the energy content of the exhaust gasses of the gas turbines is utilized to run steam and organic Rankine cycle and then generated surplus power is fed to electrolyzers to produce hydrogen. Results revealed that under the base condition exhaust temperatures of 450, 525 and 600 ˚C lead to hydrogen production of 1308, 1769 and 2191 ton per year, respectively.

In this study, two new multi-generation (hydrogen, power, heating) systems are thermodynamically analyzed and optimized. For the proposed cycles, the two systems are distinguished by the power generation cycle, so that the organic Rankine cycle and the Kalina cycle are used to produce power. Both systems also use domestic water heater for heating and proton exchange membrane electrolyzer for hydrogen production. After the thermodynamic simulation, a comprehensive study was performed for evaluating the parameters affecting hydrogen production, net output power, heating, thermal efficiency and exergy efficiency of two cogeneration systems and finally, an optimization was performed from an exergy efficiency point of view. According to the results of this study, for the organic Rankine cycle-based tri-generation system, when evaporator temperature increases exergy efficiency and hydrogen production show optimum values while for Kalina cycle-based tri-generation system, hydrogen production and exergy efficiency increase. Also, according to the study of various operating fluids for the organic Rankine cycle, the R152a as an organic Rankine cycle fluid produces more hydrogen. Furthermore, based on the optimized results for 120 °C heat source temperature, the Kalina cycle-based tri-generation system has more exergy efficiency and more hydrogen production than the organic Rankine cycle-based tri-generation system.

The use of multi-generation systems is rapidly developing in the world. Although Sabalan geothermal field is one of the important geothermal fields of Iran, the possibility of using the multi-generation systems has not yet been performed. As an attempt to fulfill the gap in the field, a new cooling, hydrogen, oxygen and power multi-generation cycle for using Sabalan geothermal wells is proposed and analyzed. In the proposed system, the double flash configuration from the Sabalan geothermal wells as the heat source is used. An organic rankine cycle is used to generate power for proton exchange membrane for hydrogen production and a LiBr-H2O absorption refrigeration system is used for cooling production. First, a simulation was done by E.E.S software and then the effects of some design parameters, such as separators pressures, evaporator temperature, pinch point temperature difference in the Rankine evaporator, generator temperature and ambient temperature on the integrated system performance are studied. A parametric study shows that the value of the thermal efficiency and cooling continuously increase with separators pressures. Also, the hydrogen production continuously decreases with the first separator while the hydrogen production increases with the second separator. According to the results, the value of the net output power, hydrogen production, cooling and thermal and exergy efficiencies of the cogeneration system are obtained as 14739 kW, 13.25 kg/hr, 10925 kW, 22.34% and 50.62% respectively.

Increasing energy demand is the main reason of designing the most efficient energy systems. Using fossil fuels to produce power in world with finite energy sources brings some problems in greenhouse gas control domain in addition to energy crisis. Since 1/3 emitted CO2 associated to human activities releases from power producing sections, oxy-fuel cycles are promising technology.Matiant cycle is one of the most well-known and developed oxy-fuel cycles where it is able to separate and capture the produced CO2 in combustion chamber. In order to propose efficient energy systems, combination of Matiant cycle with an Organic Rankine Cycle (ORC) studied from view of energy and exergy and also a parametric study carried out to show the most effective components in exergy destruction. Proposed combined cycle keeps the CO2 capturing quality of Matiant cycle besides increasing of its efficiency due to waste heat recovery. Energy and exergy efficiency of proposed cycle is 51.45 and 45.63% respectively. In exergy analysis domain, in addition to parametric study results of exergy efficiency and exergy destruction of each component has been outlined.