In this paper, the superconducting carbon dioxide cycle is re-examined and compared from the perspective of advanced and thermoconomic exergy analysis to identify real potentials and prioritize the improvement of cycle components. In advanced exergy analysis, in addition to calculating the total exogenous exergy destruction for each component, the contribution and effect of each of the other components and their combination in causing this inefficiency have also been identified. In thermoeconomic analysis of the system, the unit cost of the product, the cost of investment and the cost of destroying the exergy for the components of the system are calculated. Improvements based on advanced exergy analysis are assigned to high temperature recuperator, turbine, compressor 1, preheater, low temperature recuperator, compressor 2 and reactor, respectively. Also, based on thermoeconomic analysis, improving the turbine and reactor is not economically justified. However, the results show that even by abandoning the improvement of these two components, due to their high economic cost and by improving other components of the cycle based on the prioritization of advanced exergy analysis, it is possible to increase the efficiency of the exergy cycle from 4/29/47. There is 63% to 47.4% and cycle energy efficiency from 34.15% to 45.84%.

In this work, the combined cycle of a helium reactor gas turbine with an organic Rankine cycle is studied and compared from the perspective of conventional and advanced exergy analysis. Using Equation solving engineering software, modeling of this cycle has been done and the results of conventional energy and exergy analysis have been obtained. Then, to determine the appropriate prioritization of cycle component improvement from the perspective of advanced exergy analysis has been studied. In fact, advanced exergy analysis provides accurate information about the real potential for system performance improvement by dividing the exergy destruction of each component into endogenous, exogenous, avoidable, and Unavoidable components. The results of advanced exergy analysis show that by modifying and upgrading the components of the system, 19.1% of the total exergy destruction of the system can be reduced. According to the advanced exergy analysis, the improvement priority belongs to the compressor and then to the reactor and gas turbine. However, from the conventional exergy analysis, the reactor's exergy destruction is greater than that of the compressor and the priority is on the reactor. In addition, based on the prioritization of advanced exergy analysis, it is possible to increase the cycle exergy efficiency from 75.21% to 82.51% and the cycle energy efficiency from 51% to 56.22%.

In this case study, exergy analysis is applied to a mini two-shaft gas turbine which is located in Islamic Azad University Khomeini Shahr Branch`s Thermodynamics laboratory and a proposal presented to make exergy destruction less using a Heat Recovery Water Heater (HRWH). Calculations were done for N2=20000 (rpm) constant and various N1 and after that for N1=60000 (rpm) constant and various N2. Results revealed that the highest exergy destruction rate occurs in combustion chamber in all conditions and a huge part of exergy destruction through the turbine exhaust. Increase in N1 leads to increases in all component exergy destruction rates. On the other hand, power turbine is the only component which is affected by changes in N2 and the exergy destruction rate increases with increase in N2. Moreover, exergy gained rate within HRWH increased with increase in N1 and is almost constant with changes in N2. In the same vein, exergetic efficiency of HRWH and exergy gained rate within HRWH are increased with decrease in water outlet temperature of HRWH.

The present paper evaluates the plan of combustion air pre-heater installation on the fired heater from thermodynamics and thermos-economics point of view. As a real case study, one of the fired heaters (H_101) of Distillation unit in Tehran Oil Refinery, Iran, is intended. With applying an air pre-heater in this study, flue gases temperature falls down from 430 º C to 200 º C and combustion air temperature grows up from 25º C to 350 º C. By examining the energy and exergy analyses before and after the installation of air pre-heater, the increase in thermal efficiency by 20% and exergy efficiency by 37% and accordingly decreasing fuel consumption by 20% is observed. It is also indicated that the most exergy destruction is accrued in the fired heater (57. 24%). In this study for the first time, based on advanced exergy analyses and concepts of endogenous/exogenous and avoidable/Unavoidable parts, exergy destruction, exergy destruction cost rates and capital investment of combustion air preheater system are found which results show the endogenous and Unavoidable parts in overall system are dominant. Also, the effect of flue gases temperature (T5) on the system performance is investigated through sensitivity analyses. It is seen that with rising T5, thermal efficiency and exergy efficiency in real, theory and Unavoidable conditions decrease. The results demonstrate the majority parts of exergy destruction in fired heater and air preheater is endogenous, Unavoidable and Unavoidable endogenous. Considering the cost of air preheater and related equipment and operating and maintenance costs annually, the payback period is estimated to be less than 2 years. In this research, the EES and Excel were applied to calculate the amount.

Advanced exergy analysis is a tool to split the exergy destruction of the system to achieve a better perspective about the potentials of a system for improvements. In addition, the component interactions and their exergy destruction dependency with the other equipment are investigated through the advanced exergy analysis. For this purpose, it divides the exergy destruction calculated by conventional exergy analysis, into endogenous/exogenous and Unavoidable/avoidable. It can be concluded that the endogenous part has the most portion of exergy destruction in components. In other words, component interactions have minor effects on system irreversibility, except heat exchanger E-100, which is affected by the compressor’s position. Sensitivity analysis is carried out to study the effect of some system parameters on compressor consumption power and total exergy destruction of the system. Results show that lowering the feed temperature and raising the feed pressure, decrease the compressor power, and higher pressure ratio decreases the total exergy destruction. Optimization is also carried out to reduce the power consumption of the compressor and propylene cooler.

Regarding the growing cost of energy, shortage of resources, and environmental issues, the importance of reducing energy consumption and optimization of related industries is more evident than ever before.Solar energy is one of the suitable solutions to acquire clean and cheap energy. The first step is to design the cycle using Aspen HYSYS simulator. After that exergy analysis is carried out on the proposed system. Results show that LPT2, LPT3 and HEX2 have the highest exergy destruction and should be considered for revision. Results of exergy analysis are then examined more deeply with the help of advanced exergy analysis. In this section exergy destruction is divided into four parts, endogenous/exogenous and avoidable/Unavoidable to investigate the precise reason of the components’exergy destruction. Results show that the three components which had the most exergy destruction are the real reason behind exogenous exergy destruction of the system, so by optimizing these components we can also decrease the total exergy destruction of the system too. At last, by choosing the right variables and total produced work as the primary function, the optimization is done using the Aspen HYSYS optimizer and the optimized parameters are compared to the basic parameters which resulted in more power production and less exergy destruction and production cost.

In this study, an integrated structure of the air separation unit, natural gas liquids recovery equipped with nitrogen removal unit is developed. In this regard, advanced exergy and exergoeconomic analyses are used to examine the irreversibility, possible improvements and the cost of the inefficiencies of the process. The exergy analysis presents information on the origin of the irreversibility as well as the amount of irreversibility of each component. The results of advanced exergy analysis show that HX2, HX3, C1, C2, C3, AC1, AC3 equipment have the highest amount of the irreversibility due to endogenous exergy destruction, whereas the highest amount of the irreversibility in the rest of the equipment is because of exogenous exergy destruction. Furthermore, avoidable exergy destruction of equipment is more than the Unavoidable exergy destruction in the C1, C2, and C3. This issue shows that with the improvement of the efficiency of the equipment, it is feasible to reduce the irreversibility of these systems. In addition, the results of advanced exergoeconomic analysis show that the priority to improve the performance of the system should be devoted to the HX2, HX3, C1, C3, AC1, AC3 equipment, respectively. The AC1 air cooler and the C3 compressor have the highest amounts of investment cost of avoidable endogenous exergy destruction, respectively. The heat exchanger HX3 and air cooler AC2 and AC3 have the lowest investment cost of avoidable endogenous exergy destruction.

Energy quality is a very important criterion, which affects the economic growth of that country. In this study, a real-life case study Natural Gas Liquids plant 800, from National Iranian South Oil Company located in the southwest of Iran was considered by conventional exergy analysis, advanced exergy analysis, combined pinch and exergy analysis, and combined pinch and advanced exergy analysis methods. The results of conventional exergy analysis illustrate that the highest amount of exergy destruction belongs to compressors and heat exchangers with 510 and 629 kW respectively. The advanced exergy analysis suggested that the exergy destruction of the heat exchanger and compressor and will reduce by modifying the performance of these components. However, according to this analysis, for (E-101) heat exchanger despite having the highest rate of exergy destruction, is not in the priority of modification due to its low level of avoidable exergy destruction. Also, the avoidable, endogenous part of exergy destruction of the compressor (K103) and heat exchanger (E-102) will reduce by improving the performance of these components. In the following, and by using the combined Pinch and advanced exergy analysis diagram, it was possible to display simultaneously the energy consumptions rate and the Unavoidable exergy destruction of the heat exchanging network. According to this graphical analysis, the plant's minimum hot and cold required utilities are equal to 411 and 10,211 kW, respectively for ΔTmin of 10.645 °C. And heat exchanger E-102 has more priorities of improvement compared to other heat exchangers.

Shorter cycle times, better product quality and less product outage can be possible with faster cooling. But mold cooling channels can only be made in linear directions and limited forms via classical manufacturing methods. Therefore, it limits that performance of mold cooling. Developed in recent years additive manufacturing technologies are capable of building complex geometries and monoblock 3D products. With this technology it is possible to produce metal molds with conformal cooling channels in different forms and capable of qualified cooling. In this study, conformal cooling channels were designed in order to achieve optimum cooling in monoblock permanent mold. In this study, CFD (Computational Fluid Dynamic) analyses are performed to steady stead conditions for designed conformal cooling channels and classical cooling channel mold. Pressure drops, cooling channel outlet temperatures and exergy destructions are calculated depending on the flow velocity rate in channels. The numerical investigations of the cooling process have shown that approximately 5% higher cooling performance can be achieved with conformal cooling channels. However, the pressure drop in the conformal cooling is observed to be higher than classical cooling channel. In addition, exergy destruction in the conformal cooling channel is approximately 12% greater than the classical cooling channel.

Background: The main purpose of this study is to evaluate the energy consumption quality of the hot water production system with weather conditions of Ahvaz. Methods: The related simulation is carried out using Aspen HYSYS software, version 10. Then Aspen HYSYS and Matlab software were used for exergy and environmental exergy and environmental exergy analyzes. Results: According to the study results, the exergy analysis showed that the highest exergy efficiency of the rotating components is related to the K100 compressor with 87. 63%. Also, the lowest exergy destruction rate of the rotating components is related to the pump P100 with 0. 52 kW. Also, an analysis of the effects of equipment on the environment from the perspective of life cycle assessment (LCA) and the effect of exergy destruction on the environment was conducted on the equipment so that the fb solar collector had the highest value among other equipment, indicating the greatest environmental effect of the inefficiency of this equipment. Compressor K101 should also be reviewed for LCA due to the high percentage of environmental factors. Conclusion: The results show that the environmental exergy analysis of the hot water production system can identify inefficient equipments and their impact rate on the environment.