Exergy Analysis Method Research Articles

Application of Exergy Analysis in Flue Gas Condensation Waste Heat Recovery System Evaluation

Flue gas condensation heat recovery technology has a good technical and economic performance in industrial exhaust gas waste heat recovery. Thermal efficiency analysis is the traditional analysis method for the flue gas condensation heat recovery system but it cannot reflect the recovered heat degree. Exergy analysis, which can reflect the recovered energy heat degree, was first applied to the evaluation of a flue gas condensation waste heat recovery system in this paper. The calculation method of wet flue gas exergy is more complex as both a heat and mass transfer is presented. Flue gas waste heat exergy efficiency (EE) and the flue gas waste heat exergy utilization rate (EUR) were proposed as the evaluation indexes for exergy analysis. The exergy analysis method was applied to the comparative evaluation of three recovery schemes in a practical project. The results show that when the water vapor content of wet flue gas is less than 10%, the condensed water exergy can be neglected when calculating EE. The EUR could be used as a comprehensive index for comparing different waste heat recovery schemes, and EE could be used to judge whether the energy grade of heat exchange equipment was seriously decreased. Exergy analysis could effectively make up for the deficiency of thermal efficiency analysis that could not reflect the waste heat grade utilization. Exergy analysis and thermal efficiency analysis are recommended to be used simultaneously to make a more comprehensive analysis and evaluation of the system.

EN Thermodynamic analyses of heat exchangers in cryogenic systems

The problems of thermodynamic analysis associated with the heat exchangers that used in cryogenic technology are discussed. Heat exchangers of high and medium pressure air separation and fluidizing plants operating at different temperature levels were selected for modelling. There are many features according to which the classification of heat exchangers is made. These features include such facts as the number of flows of the working fluid, the relative direction of the flows of working substances, the purpose of the apparatus, and others. These features are also associated with the design of heat exchangers and the software for the design, which contains thermodynamic calculations. The general thermodynamic approach is based on the equation for the values of the thermodynamic efficiency characteristics and the restrictions imposed on them At the exergy method of analysis, the corresponding balance is based on the energy balance equation. On the basis of this balance, the losses from irreversibility of the selected object and its exergy (thermodynamic) efficiency can be directly determined In a heat exchanger, both types of losses exist, but it is not possible to reveal the contribution of each type to total losses using only the exergy balance. This is due to the fact that this balance is drawn up for a closed control surface that reflects a physical object and not logical reasons associated with this object. Meanwhile, the determination of technical losses is an urgent tasks since the change in the thermodynamic parameters that regulate these losses are the basis for increasing the coefficient of the thermodynamic efficiency of the analyzed system A method and an algorithm for calculating the components of losses from irreversibility in these heat exchangers are proposed. The exergy method of thermodynamic analysis was used to calculate the components of these losses for some two-flow heat exchangers. The investigation of the obtained calculation results is presented

Advanced exergy analysis of an integrated solid waste fueled cogeneration system based on organic Rankine Cycle for different working fluids

In this study, the performance evaluation of an ORC-based solid waste-powered cogeneration system was carried out using conventional and advanced exergy analysis methods. Eight different working fluids including dry (isopentane, n-pentane, n-octane, n-heptane), isentropic (R141b, R123), and wet (methanol, water) types were selected for the evaluation. The total capacity of the heat source was determined with the data obtained from the assessment of municipal solid wastes with different calorific values ​​by the characterization method. Energy and exergy analyses were carried out for each component to examine the effect of selected cycle parameters, including evaporator pressure, intermediate pressure, and condenser pressure, and determine the optimum working fluid for the system. The exergy destruction in the components was split into avoidable/unavoidable and endogenous/exogenous parts in the advanced exergy analysis to identify the improvement potentials and the interaction between the components. The thermal and exergy efficiency values ​​reach the highest values ​​of 81.36 % and 40.76 %, respectively. R141b performs as the best working fluid, while the lowest performance is obtained from water. About 121.3 kW of power generation and 918.2 kW of process heat were obtained from the ORC-CHP system using R141b at 1400 kPa evaporator pressure. Conventional exergy analysis states that the evaporator, process heater, and turbine are the most critical components, accounting for 67.94 %, 19 %, and 4.92 % of the total exergy destruction rate, respectively. The advanced exergy analysis shows that the priority should be on the turbine having the largest share of the avoidable part. The avoidable part, which accounts for 14.5 % of the total exergy destruction, can be reduced by system improvements.

Energy Analysis and Verification of a Constant-Pressure Elastic-Strain Energy Accumulator Based on Exergy Method

Focusing on the low energy-storage efficiency and unstable energy output of existing accumulators, this paper proposes a novel constant-pressure elastic-strain energy accumulator based on the rubber material hyperelastic effect. The proposed accumulator can store and release energy at a constant pressure. Based on the exergy analysis method, the charging/discharging energy storage efficiency of a constant-pressure elastic-strain energy accumulator was analyzed. Then, the Mullins effect on the rubber airbag over multiple charging/discharging cycles was studied. Finally, a test platform was established to verify the energy storage efficiency, as well as the expansion and contraction pressure stability of the rubber accumulator during charging/discharging cycles. The experimental results showed that the energy storage efficiency calculation by the exergy analysis method was more accurate compared with the enthalpy analysis method. In tests with more than 200 cycles, the rubber airbag energy storage efficiency was always higher than 76%, and the expansion and contraction pressure errors at a steady state were less than 2.92 and 1.79 kPa, respectively. The results showed that the rubber airbag could be used as an effective energy storage component, which is very meaningful for energy recovery in pneumatic or hydraulic systems.

Energy, exergy, economic, environmental (4E) and dynamic analysis based global optimization of chemical looping air separation for oxygen and power co-production

Chemical looping air separation (CLAS) is a promising oxygen generation technology due to its energy conservation nature. It can be integrated with power generation system (PGS) to improve energy efficiency by utilizing high waste heat of CLAS system. This work presents a global optimization strategy for revamping the CLAS-PGS system, in which the comprehensive performance of the system is evaluated by a novel energy, exergy, economic, environmental, and dynamic (4E-1D) analysis method. First, two original after-burner reheating (ABR) and mixed heating (MH) technologies are proposed to optimize the CLAS-HI-PGS scheme. Second, all the schemes are simulated to provide steady-state simulation results for global 4E analysis, and optimized by genetic algorithm (GA) with minimum capital investment cost (CIC) as target to further improve energy efficiency of CLAS-PGS. Finally, the dynamic behaviors of the schemes are investigated with effective control schemes designed to ensure safe and stable operation of CLAS-PGS. In order to measure additional losses caused by disturbance, the 4E analysis is also combined with dynamic analysis. The results show that the scheme combing MH with CLAS-PGS (CLAS-MH-PGS) displays best, proving the effectiveness of this proposal and providing a new way for CLAS-PGS industrial application.

Conventional and advanced exergy analysis of a novel wind-to-heat system

Exergy analysis are carried out on a novel 100 kW wind-to-heat system to investigate the thermodynamic performances by employing the experimental data. Nine different combinations of the wind speed and water flow rate are selected as the typical operating conditions. Through the conventional exergy analysis, the wind turbine accounts for the most of the system's total exergy destruction at high wind speeds. In terms of the heat pump subsystem, the compressor is the most critical component, followed by the condenser. For further obtaining the optimal design directions of the key components, the advanced exergy analysis is applied to this system. By establishing the mathematical model, the exergy analysis of the ideal conditions, experimental conditions and unavoidable conditions are compared. Averagely 87.32% exergy destruction of the compressor is endogenous and avoidable, which can be decreased by optimizing the internal structure parameters. The average proportions of the avoidable exergy and endogenous exergy destruction of the condenser are 57.48% and 68.41%, respectively. Both the internal parameters of the condenser and interactions with other components must be taken into consideration. The optimizing potential of the wind-to-heat system through exergy analysis methods can be used for further research and improvement of the system.

Task-Level Energy Efficiency Evaluation Method Based on Aero-Engine Thrust-Specific Fuel Consumption with Application to Environment Control System

There has recently been a considerable and dramatic change in the system design of some future aircraft. The use of electrical energy has led to a demand for rapid technology development in the environment control system (ECS). Extracting energy from the aero-engine in the form of compressed air and electric power to drive the ECS directly affects aero-engine fuel economy. There is an urgent demand for a task-level energy efficiency evaluation method to guide energy and heat sink scheduling. This paper takes the F22 Raptor fighter jet as the research object and analyzes the influence of bleed air and electric power on the thrust and thrust-specific fuel consumption (TSFC) based on the exergy analysis method. First, a two-step TSFC surrogate model is constructed, and a task-level energy efficiency evaluation method is proposed. The error of the TSFC surrogate model is less than 5%, which means the accuracy of the model is sufficient to meet the needs of engineering. Then, the task-level energy efficiency evaluation results show that the vapor cycle has significant fuel economy when the cooling capacity is large, while the air cycle has certain advantages with a small cooling capacity. The method of TSFC surrogate model reduces computational complexity of evaluation with enough accuracy, which can provide a reference for selecting ECS type and guide the optimization of the cooling capacity distribution of the air cycle and vapor cycle.

Experimental investigation and exergy analysis of a high concentrating photovoltaic system integrated with spray cooling

A high concentration photovoltaic/thermal system (HCPV/T) coupled with a spray cooling device is proposed in this study, which can effectively reduce the contact thermal resistance between the solar cell and the heat exchanger. Electrical analysis of solar cells and thermal analysis of spray cooling heat exchangers are firstly investigated through experiments and simulations. Compared with the traditional cooling method, the spray cooling is covered in the form of a surface for cooling, which can improve the temperature uniformity of the solar cell. To evaluate the performance of the new system from the perspective of energy quality, an exergy analysis method suitable for HCPV/T systems utilizing high pressure is proposed. The performance of the hybrid HCPV/T system is compared with the independent HCPV system. The result shows that the electrical efficiency of the hybrid system can not only remain above 27%, but also the thermal efficiency of the system can reach above 45%. In addition, under high temperature inlet conditions, a suitable outlet temperature can be obtained, the energy quality of the system can be improved, and the total exergy efficiency can reach 34%. These findings greatly expand HCPV/T systems to achieve higher performance.

Thermodynamic analysis of two novel very high temperature gas-cooled reactor-based hydrogen-electricity cogeneration systems using sulfur-iodine cycle and gas-steam combined cycle

In this paper, two novel system layouts are proposed to improve the thermodynamic performance of the conventional very high temperature gas-cooled reactor (VHTR)-based hydrogen-electricity cogeneration system using sulfur-iodine (S–I) cycle and gas-steam combined cycle (GSCC). The heat and electricity consumption data of the S–I cycle are obtained from our previous Aspen Plus simulation results, and the thermodynamic model of the entire hydrogen-electricity cogeneration system is established using energy and exergy analysis methods. The performance of the system under benchmark conditions is analyzed, and the effects of several key operating parameters on system performance are investigated. The results show that with these two new system layouts, the thermal efficiency and exergy efficiency of the conventional system are improved by 8.56%–10.27% and 9.01%–10.82%, respectively. The largest exergy loss of the system occurs in the VHTR, and the exergy efficiency of the S–I cycle is very low, only about 50.8%. Therefore, when the hydrogen production load is large, it is very important to optimize the process flow and operating parameters of the S–I cycle. Besides this, it is found that the S–I cycle-based nuclear hydrogen production efficiencies are lower than the GSCC-based nuclear power generation efficiencies.

Energy, exergy, economic and environmental analysis of photovoltaic/thermal integrated water source heat pump water heater

The photovoltaic thermal integrated water source heat pump (PV/T-WSHP) water heater system can meet the demand for not only the domestic hot water but also the electricity production. To comprehensively analyze the benefits of the PV/T-WSHP water heater system, energy, exergy, economic and environmental analysis method was applied. A TRNSYS model of the PV/T-WSHP water heater system was developed based on the existing experimental setup, and validated by the experimental data. A combined system of single PV system and single air source heat pump water heater (PV + ASHP) system model was also built for comparison. The simulated results indicated the PV/T-WSHP water heater system had a 25.3% improvement in electrical conversion efficiency, a slightly lower EER of 3.71 and a significant reduction in annual exergy loss, comparing with the combined PV + ASHP system. In addition, the annual cost of the PV/T-WSHP water heater system was 217.7 yuan lower than the combined PV + ASHP system. The PV/T-WSHP heat water system and the combined PV + ASHP system could annually save the standard coal of 0.62 tons and 0.50 tons, respectively. This study provides an effective method to comprehensively analyze the performance of the PV/T-WSHP water heater system.

Advanced exergy analysis of a CO2 two-phase ejector

Ejector is meaningful and valuable to improve the transcritical CO2 refrigeration system. To study in-depth on the exergy destruction is significant for the performance enhancement of CO2 ejector. This paper presents a comprehensive investigation on the exergetic performance of CO2 two-phase ejector using conventional and advanced exergy analysis method to explore the interactions among ejector components and their improvement potential. The effects of primary flow pressure, suction flow temperature and area ratio (motive nozzle throat area to mixing chamber area) on the ejector exergy destruction are discussed. The results indicate the largest exergy destruction in the ejector is caused by the mixing chamber, followed by the motive nozzle, diffuser and suction chamber. Based on the avoidable exergy destruction rate and exergy destruction proportion, the order of optimization potential for ejector components is motive nozzle, diffuser, mixing chamber and suction chamber. However, the sum of avoidable exergy destruction of mixing chamber is the largest, which has the highest priority for improvement of overall ejector performance. The exogenous exergy destructions of the mixing chamber and diffuser are largely caused by the motive nozzle, and the exergy destructions would be increased with the improvement of motive nozzle performance. There exists an optimal primary flow pressure 9.5 MPa to minimize the exergy destruction of the each component of the ejector. To reduce the suction flow temperature and the ejector area ratio can decrease the avoidable exergy destruction of the components. Moreover, the variation of operating parameter has no effect on the optimization sequence of the overall ejector and its components. This work would provide a helpful way to guide the optimization on the ejector efficiency.

Analysis and assessment of a novel organic flash Rankine cycle (OFRC) system for low‐temperature heat recovery

AbstractIn this paper, a novel organic flash Rankine cycle (OFRC) system for low‐temperature heat recovery is analyzed and optimized using the 3E (energy, exergy, and economic) analysis method and particle swarm optimization algorithm, respectively. Five environmentally friendly organic fluids and three typical heat source conditions are simultaneously discussed during the parametric analysis and optimization process, to obtain a comprehensive understanding of the thermo‐economic characteristics of this novel system. The main analysis results show that the biggest exergy loss of the OFRC system is caused by the condenser, followed by the evaporator. About 70% of the specific power cost is caused by the capital investment of the system, and more than 60% of the capital investment is spent on purchasing the high‐pressure and low‐pressure expanders. Under the same operating conditions, the working fluids with high critical temperatures can achieve higher cycle thermal efficiency and lower specific power costs than those with low critical temperatures. The optimization results show that the OFRC system is able to achieve a better thermodynamic performance than the organic Rankine cycle (ORC) and organic flash cycle (OFC) systems, and when the heat source's inlet temperature is set to 100°C, 120°C, and 140°C, R245fa, R290, and R152a are, respectively, recommended as the best working fluid for the OFRC system. Besides this, it is found that the OFC system has the worst thermo‐economic performance, and the ORC system can achieve the lowest specific power cost. A new finding is that, for all three systems, the higher the critical temperature of the working fluid, the lower the specific power cost of the system.

Performance evaluation of a novel CCHP system integrated with MCFC, ISCC and LiBr refrigeration system

This paper proposes a novel combined cooling, heating, and power (CCHP) system integrated with molten carbonate fuel cell (MCFC), integrated solar gas-steam combined cycle (ISCC), and double-effect absorption lithium bromide refrigeration (DEALBR) system. According to the principle of energy cascade utilization, part of the high-temperature waste gas discharged by MCFC is led to the heat recovery steam generator (HRSG) for further waste heat utilization, and the other part of the high-temperature waste gas is led to the MCFC cathode to produce CO32−, and solar energy is used to replace part of the heating load of a high-pressure economizer in HRSG. Aspen Plus software is used for modeling, and the effects of key factors on the system performances are analyzed and evaluated by using the exergy analysis method. The results show that the new CCHP system can produce 494.1 MW of electric power, 7557.09 kW of cooling load and 57,956.25 kW of heating load. Both the exergy efficiency and the energy efficiency of the new system are 61.69% and 61.64%, respectively. Comparing the research results of new system with similar systems, it is found that the new CCHP system has better ability to do work, lower CO2 emission, and can meet the cooling load, heating load and electric power requirements of the user side at the same time.

Energy and exergy analyses of ammoniated salts based thermochemical sorption heat storage system

Thermal energy storage (TES) is a critical technology to improve energy infrastructures by harvesting low-grade heat and renewable energy. Thermochemical sorption heat storage (TSHS) is considered to be the most promising TES technology due to excellent energy storage performance and flexible working mode. Ammoniated salts with high adsorption capacity and reaction enthalpy are favorable heat storage materials. Using energy and exergy analyses to evaluate heat storage performance is conducive to the highly utilization of the energy and optimization of the energy system. In this work, the thermodynamic performance of the sorption heat storage cycle with ammoniated salts was surveyed through the energy and exergy analysis methods. The general efficiencies of four salts for the sorption heat storage during charging, discharging and the whole system were estimated. Results showed that SrCl2 and SrBr2 are expected to be the most promising materials for the sorption heat storage among the four chemical salts. The overall energy efficiencies of SrCl2-NH3 and SrBr2-NH3 sorption heat storage systems are 39.8% and 41.6%, respectively, and the corresponding overall exergy efficiency are 17.3% and 13%. The Carnot factor-induced efficiency of SrCl2-NH3 and SrBr2-NH3 sorption heat storage systems are 0.123 and 0.087, respectively.

Optimization and comparison of two improved very high temperature gas-cooled reactor-based hydrogen and electricity cogeneration systems using iodine-sulfur cycle

To enrich the existing research methods and content, two improved very high temperature gas-cooled reactor and iodine-sulfur (I–S) cycle-based nuclear hydrogen and steam and helium gas turbines electricity cogeneration systems, including the series connection system (SCS) and the parallel connection system (PCS), are proposed and studied. The energy and exergy analysis methods are used to model these two systems, and Aspen Plus is adopted to build the I–S hydrogen production system. The energy consumption and thermal efficiency of the I–S system are analyzed in detail, and the parametric optimization of two improved systems is performed using particle-swarm optimization (PSO) algorithm. Lastly, the performance comparison of the two systems under different operating conditions is conducted. The simulation results show that more than 99% of the energy consumption of the I–S system is occupied by H2SO4 section and HIx section, and the system's thermal efficiency is estimated to be in the range of 17.7%–43.3%. After using an internal heat exchange network, a conservative thermal efficiency of 23.7% is achieved. The optimization results show that under zero hydrogen production load, the proposed PCS and SCS can respectively achieve the net electrical power outputs of 172.8 MW and 125.7 MW, the global thermal efficiencies of 49.36% and 35.91%, and the global exergy efficiencies of 51.94% and 37.79%. With the increase of hydrogen production load, the global efficiencies of both systems decrease significantly, but the decreasing rate of PCS is faster than that of SCS. In addition, the performance comparison results indicate that when the hydrogen production load is small or the intermediate heat exchanger's primary side helium outlet temperature is close to the reactor inlet temperature, the PCS would be a better option than the SCS.

Aeropropulsive Performance Analysis of Axisymmetric Fuselage Bodies for Boundary-Layer Ingestion Applications

Boundary-layer ingestion (BLI) has been proposed as one of the novel airframe–engine integration technologies to reduce aircraft fuel consumption. The current numerical analysis involves the evaluation of the effect of fuselage design on the power consumption of a boundary-layer ingesting propulsor modeled as an actuator volume without nacelle. An axisymmetric fuselage model is used as a canonical case to study BLI in transonic flight conditions. The flowfield is investigated through the power balance and the exergy analysis methods. Results show that the fuselage geometry and flight conditions only have a minor effect on the BLI power saving benefit when compared to the effect on the drag power of the fuselage. This indicates that, for the range of fuselage geometries and flight conditions studied, the isolated fuselage drag can be used for a qualitative performance assessment of different fuselage designs even for BLI configurations. Also, the power saving results obtained based on the power balance and the exergy analysis methods show similar qualitative trends for the fuselage geometries and flight conditions considered. Furthermore, the BLI propulsor has a negligible effect on the upstream anergy generation rate. Turbulence and temperature gradients within the flow are the important reasons for the deterioration of the BLI propulsor performance as expected.

Evaluating the influence of H2O phase state on the performance of LNG oxy-fuel combustion power plant: Exergy and exergoeconomic analyses

Oxy-fuel combustion with H2O as diluent is regarded as one of the most promising technologies to realize the carbon capture process in power plants. The phase state of H2O has a significant influence on system performance. In this paper, a novel oxy-fuel combustion system with the utilization of liquefied natural gas (LNG) cold energy is proposed. The effect of H2O phase states for improving potential and economy of the system is quantified using the exergy and exergoeconomic analysis methods. Results show that an O2/water system operates better than an O2/steam system, achieving an overall exergy efficiency of 36.35%, which is 4.7% higher than that of the latter. In the O2/water system, 11.99% of the exergy destruction can be avoided; this is, considerably higher than the 8.79% avoidable exergy destruction in the O2/steam system. In terms of economic feasibility, the total investment in the O2/water system is 1.86×105$/h, which is distinctly lower than the 3.47×105$/h investment in the O2/steam system. Moreover, the avoidable total cost rate in the O2/water system exceeds 53.36%, which is significantly higher than the 33.61% proportion in the O2/steam system. These results reveal that water is more suitable than steam for moderating the combustion temperature in oxy-fuel systems in terms of economic feasibility and exergy efficiency. This study is anticipated to have a positive influence on the global transition to a low-carbon future.

Thermodynamic analysis on a modified auto-cascade refrigeration cycle with a self-recuperator

This paper proposes a modified auto-cascade refrigeration cycle (MARC) with a self-recuperator. The introduced self-recuperator and associated expansion valve effectively increases the refrigerant enriched with more low-boiling component in the evaporator. This case could improve the cycle performance by further choosing appropriate design-dependent cycle parameters. The energy and exergy analysis methods are used to compare and evaluate the performance of MARC with conventional auto-cascade refrigeration cycle (CARC). The simulation results show that under all given working conditions, the COP and exergy efficiency of MARC are superior to those of CARC. Among R290/R170 and R600a/R1150, R600a/R1150 is much better refrigerant mixture. Under a typical working condition, the COP of MARC using R600a/R1150 is 68.17% higher than that using R290/R170. The performance improvement of MARC is more obvious when R600a/R1150 is used. Under the typical working condition, the COP of MARC is increased by 6.24% and 24.17% using R290/R170 and R600a/R1150, respectively. When initial mass fraction of R1150 is about 0.6, the two cycles have maximum COP and exergy efficiency, and the maximum COP of MARC is 24.26% higher than that of CARC. In addition, the increase in the two-phase flow vapor quality at the condenser outlet can improve the COP, but reduce the refrigeration capacity. The COP of MARC increases by 37.56% when the quality increases from 0.4 to 0.6. It is also found for MARC that COP and refrigeration capacity are positively correlated with intermediate pressure.

Electric power generation technology of natural gas pressure reduction: Insights from black box-gray box hierarchical exergy analysis and evaluation method

Based on the “three box” exergy analysis model, a black box-gray box hierarchical exergy analysis and evaluation method is put forward in this paper, which is applied to evaluate the power generation technology of differential pressure produced by natural gas expansion. By using the exergy analysis theory, the black box - gray box hierarchical exergy analysis models of three differential pressure power generation technologies are established respectively. Firstly, the “black box” analysis models of main energy consuming equipment are established, and then the “gray box” analysis model of the total system is established. Based on the calculation results of exergy analysis indexes, the weak energy consumption equipment in the whole power generation process is accurately located. Taking a gas field in southwest China as an example, the comprehensive energy consumption evaluation of the three power generation technologies is carried out, and the technology with the best energy consumption condition among the three technologies is determined. Finally, the rationalization improvement measures are put forward from improving the air tightness, replacing the deflector and reducing the flow loss.

Studies on the performance of distributed combined cooling, heat and power system under off-design conditions based on exergy analysis

This paper adopts the exergy analysis method of second law of thermodynamics to analyze the characteristics of off-design conditions of distributed combined cooling, heat and power system (CCHP). The research results show that off-design conditions are the primary cause of the performance decline of the system. Under the off-design conditions, although the system’s power generation and cooling capacities decline with the reduction of load, the cooling capacity declines more slowly than generating capacity. When the gas turbine load drops under 60%, the distributed combined cooling, heat and power system may not save energy. If the low grade residual heat in the system could be effectively used, it will obviously improve the system’s performance under off-design conditions. Combustor, high pressure producer, and turbine change significantly in grade differences during the change of load in gas turbine, which also means that these three parts are the areas with the highest potential for improvement of the system’s performance. The biggest loss of system exergy occurs in combustor and high-pressure producer.