Exergy Destruction Of Components Research Articles

Exergy analysis and improvement of helium internal purifier

Exergy analysis was applied to the evaluation of helium internal purifier in this paper. The important operating parameters has been given to determine the exergy destructions in components as well as in the entire cycle of internal purifier. The analysis results show that the recovery of liquefied air energy can improve the performance of purifier and the exergy destruction of different heat exchanger is different. Results from the analysis helped evolving guidelines for designing appropriate technological process for practical helium internal purifier. An internal purifier with an optimized structure was designed to remove air impurities up to 10 mol%, beyond previous maximum impurity content. The impact on liquefaction capacity is minimized because of the small consumption of cold flow. The achievable performance was also provided in this paper. The purifier could remove air impurities up to 8 mol%.

Coupling a Gas Turbine Bottoming Cycle Using CO2 as the Working Fluid with a Gas Cycle: Exergy Analysis Considering Combustion Chamber Steam Injection

Gas turbine power plants have important roles in the global power generation market. This paper, for the first time, thermodynamically examines the impact of steam injection for a combined cycle, including a gas turbine cycle with a two-stage turbine and carbon dioxide recompression. The combined cycle is compared with the simple case without steam injection. Steam injection’s impact was observed on important parameters such as energy efficiency, exergy efficiency, and output power. It is revealed that the steam injection reduced exergy destruction in components compared to the simple case. The efficiencies for both cases were obtained. The energy and exergy efficiencies, respectively, were found to be 30.4% and 29.4% for the simple case, and 35.3% and 34.1% for the case with steam injection. Also, incorporating steam injection reduced the emissions of carbon dioxide.

Advanced exergoeconomics of a steam power plant based on double-tier splitting of exergy destruction rates

The advanced exergy and exergoeconomic analysis methodologies excel over their conventional counterparts by quantifying endogenous/exogenous exergy destruction rates and related costs that reveal the interactions among system components. By quantifying avoidable/unavoidable losses, they also reveal the potentials for component improvements that are practically achievable. These data are imperative for improving the cost-effectiveness of thermal systems. This paper presents the performances of a complex gas-fired power plant obtained via an advanced exergoeconomic analysis. The study advances existing studies by undertaking second-tier splitting of exergy destruction cost rates and associated investment cost rates to determine avoidable endogenous, unavoidable endogenous, avoidable exogenous, and unavoidable exogenous cost rates of the plant’s components. Component exergy destruction cost rates were found to be predominantly unavoidable, while most of the component investment cost rates were avoidable. Except for the low pressure heater 3, exergy destruction cost rates are endogenous in all the plant components, contributing 84% of overall cost rates. The proportions of exergy destruction cost rates and investment cost rates of the plant that are avoidable endogenous were 21% and 28% respectively, while the respective portions that are avoidable exogenous were 4% and 27%. Furthermore, it was shown that as much as 96.3% improvements in overall plant cost-effectiveness were achievable by eliminating avoidable endogenous exergy destruction cost rates and investment cost rates for major components of the plant.

Sensitivity analysis of avoidable and unavoidable exergy destructions in a parallel double‐effect LiBr–water absorption cooling system

AbstractA parametric study has been carried out based on advanced exergy assessment for a parallel double‐effect LiBr–water absorption chiller. The advanced exergy method provides the real potential of the equipment for improvement in the system by recognizing the avoidable irreversibilities. The sensitivity analysis of various parts of the exergy destruction (endogenous avoidable, endogenous unavoidable, exogenous avoidable, and exogenous unavoidable) in system components and the overall performance (coefficient of performance, exergy efficiency, and modified exergy efficiency) of the system has been done to identify the actual potential of different components of the system to improve the overall performance of the system relative to operational parameters. Operational parameters include the heat source temperature, heat sink temperature, and the difference between the absorption and condensation temperature. The results showed that by modifying and improving the performance of components, 18.5% of the total exergy destruction of the system could be reduced. The modified exergy efficiency reduces sharply (nearly 40%) with the rising heat sink temperature. The endogenous exergy destruction increases in all system components except the condenser and evaporator by the heat source temperature increase. With the increase in the heat sink temperature, the avoidable part of the total exergy destruction in the system increases due to the significant rise in the avoidable exogenous exergy destruction in the components, and the unavoidable endogenous exergy destruction decreases (more than 200%) in the absorber. Increasing the condensation temperature reduces the unavoidable endogenous exergy destruction in the components except for the low‐temperature heat exchanger.

Advanced exergy analysis of NH3/CO2 cascade refrigeration system with ejector

Aiming at the NH3/CO2 Cascade Refrigeration System with ejector (CRSE), this paper establishes the mathematical model of the refrigeration cycle and compares it with the literature based on thermodynamic analysis. Advanced exergy analysis on the CRSE is carried out and the exergy destruction of components in the system are divided into two ways: avoidable/unavoidable exergy destruction and endogenous/exogenous exergy destruction, and combine the two ways to clarify the types and values of exergy destruction in components, which provides a direction for the improvement of the system. The analysis shows that the avoidable exergy destruction of the system accounts for 38.674% of the total exergy destruction, and the proportion of endogenous exergy destruction and exogenous exergy destruction in the total exergy destruction of the system is 77.772% and 22.228% respectively. The improvement potential of the system is very high, and the low-temperature compressor, condenser, and intermediate heat exchanger should be paid special attention to in the improvement.

Thermodynamic assessment of a triple cascade refrigeration system utilizing hydrocarbon refrigerants for ultra-low temperature applications

• Triple cascade refrigeration system is implemented for ultra-low temperature applications. • System performance analyzed for hydrocarbon-based environment friendly refrigerants. • Temperatures of MTC and LTC condenser are evaluated for maximum COP values. • At different evaporator temperatures, better performance is gained by different pairs. • Heptane and Toluene are recommended in MTC for −120 °C to −110 °C, and −100 °C to −90 °C, respectively. This work presents a detailed thermodynamic analysis of a triple cascade vapor refrigeration system (TCRS) utilizing hydrocarbon refrigerants for ultra-low temperature application. Different hydrocarbon refrigerants pairs are used in different circuits (High temperature circuit HTC, Mid temperature circuit MTC, and Low temperature circuit LTC) to obtain the most suitable refrigerant combination by mathematical modeling of the system. The design and operating parameters considered in this study include (1) evaporator temperature (2) LTC condensation temperature (3) MTC condensation temperature. A thermodynamic analysis consisting of energy and exergy analysis were employed in terms of operating conditions to obtain COP, total compressor work, exergy efficiency, total exergy destruction, mass flow rate and discharge temperatures of compressors. Furthermore, an analysis on component exergy destruction was conducted to show the possibilities of improvement of TCRS utilizing the hydrocarbon refrigerants. The results suggest that at different evaporator temperatures different hydrocarbon refrigerants on TCRS give higher COP and exergy efficiency. The highest COP and exergy efficiency at −100 °C evaporator temperature was calculated to be 0.5931 and 54.446 %, respectively. This study also suggests that hydrocarbon refrigerants can be used in ultra-low temperature applications without compromising the thermodynamic performance of the refrigeration system.

Advanced Exergy Scrutiny of a Dual-loop Organic Rankine Cycle for Waste Heat Recovery of a Heavy-duty Stationary Diesel Engine

In this paper, the normal exergy scrutiny (NES) and advanced exergy scrutiny (AES) of a waste heat recovery (WHR) system was performed. The proposed system contains a dual-loop organic Rankine cycle (DORC) which recovers the available waste heat of the intake air, exhaust gas, and coolant streams of a 12-cylinder heavy-duty stationary diesel engine. A well-known method of the AES called the thermodynamic cycle approach is utilized to determine each component exergy destruction parts namely exogenous/endogenous, unavoidable/avoidable, etc. Results showed that 59.04 kW from the 258.69 kW total exergy destruction rate of the system could be eliminated (22.82% of the total exergy destruction rate). The total avoidable exergy destruction part of the low-temperature loop accounts for 46.62 kW, which indicates that it requires more attention than that of the high-temperature loop by 12.42 kW. Furthermore, it is revealed that to enhance the overall productivity of the system, there is a relatively significant difference in priority order regarding the improvement of system components. The AES has proposed this ranking for improvement priority of components: condenser, expander 2, expander 1, respectively. While the NES has specified the priority as the evaporator 1, condenser, expander 2, respectively.

Environmental impact assessment of a real geothermal driven power plant with two-stage ORC using enhanced exergo-environmental analysis

Geothermal driven power plants (GPPs) with two-stage ORC are mostly used in low-temperature geothermal fields around the World. The environmental impacts of these GPPs create a gap in the literature. In this study, enhanced exergo-environmental analysis for the GPP and its components is conducted as a case study. With the analysis, the component-related, exergy degradation-related, and pollution formation-related environmental impacts (EIs) are separated endogenous/exogenous and avoidable/unavoidable parts. In this way, detailed information about the interaction and improvement potential between components is acquired by using the recommended performance indicators. The results of the study show that for the enhanced exergo-environmental analysis, EI related to exergy destruction of components is predominated. In the traditional exergo-environmental analysis the total amount of EI is condenser with 1.386 Pt/h while in the enhanced one the highest avoidable-endogenous exergy destruction is condenser with 716 Pt/h. The value of EI which is caused by electricity generation is 0.108 Pts/kWh. The EI value of geothermal fluid is 11.8 Pt/GJ. The EI value of the plant's avoidable-endogenous pollution formation is 8 Pt/h. As the reason for this, the mass flow rate of the geothermal fluid steam and the amount of NCG gas in it are effective. Eventually, if the plant could be operated under enhanced analysis' operation conditions, the EI of released CO2 value can be reduced by 8.4% by carbon capture and storage. Thus, the details of the analyzes performed for the plant are expected to guide the researchers.

Comparison of advanced air liquefaction systems in Liquid Air Energy Storage applications

The dynamic growth of renewables in national power systems is driving the development of energy storage technologies. Power and storage capacity should correspond to system-scale requirements in the field of power and capacity. One such technology is liquid air energy storage. As the main energy expenditures in this system are related to the liquefaction module, authors focused their research on analysis of the advanced liquefaction modules. The six most common liquefaction sections were considered. Depending on the regasification section pressure, various amounts of cold media can be obtained, stored, and used during liquid air energy storage system charging mode. Mathematical modelling results show that when the regasification section pressure is below 100 bar, the type of liquefaction system used has no significant influence on the unit energy expenditures of liquefaction section. Since additional air cooling is desired for higher pressure values, appropriate choice of liquefaction system type can minimise unit energy expenditures for air condensation. One of the main parameters from the efficiency point of view is the temperature before the throttling valve, as lower values contribute to a reduction in recirculated flow, leading to lower power demands for compressors. The highest efficiencies for almost all considered cases were reported for the Kapitza system: 57.72% for 100 bar regasification pressure. Importantly, the Kapitza and Heylandt systems retain good efficiency with higher regasification pressures, until 160 bar. For the other cases, the discrepancies between efficiencies for 100 bar and 160 bar are significant. The highest difference was observed for the simplest system – Linde-Hampson – where the efficiency drop exceeds 12%. For the best analysed system (Kapitza) exergy analysis were leaded. The main single component exergy destruction was reported for the Joule-Thompson valve (25.56%), which is related with isenthalpic throttling of air. In general, the highest share of exergy destruction in the system occurs in the heat exchangers (26.15% in total).

Optimization of thermodynamic performance with simulated annealing algorithm: A geothermal power plant

Binary geothermal power plants (GPP) always attract researchers’ attention as they are renewable-energy operated, low-temperature, high-performance, environmentally-friendly, and baseload power plants. In addition, they need to be monitored, controlled and optimized due to their complex structure and functioning. This article presents the application of the Simulated Annealing (SA) algorithm for the thermodynamic performance optimization on the verified thermodynamic model of the SINEM GPP operating in Aydın, Turkey. This algorithm is also compared to the Gravitational Search Algorithm (GSA). By using these methods, 17 optimization parameters in the plant model are simultaneously optimized for maximum exergy efficiency. Study results show that the exergy analysis, gravitational search algorithm and simulated annealing algorithm respectively determined the exergy efficiency of the plant as 14.48%, 30.62%, and 38.49%. The SA algorithm has a better performance compared to the other two methods. System components such as condensers, vaporizers, and pumps are made more efficient using the SA algorithm. In addition, the most effective parameters of the plant are evaporator pressure differences and the mass flow of ORC’s working fluid. By using GSA and SA algorithm, the gross electricity generation in the power plant can be increased by 2.11 MW and 3.15 MW, respectively. While GSA uses the procedure of reducing the amount of component exergy destruction, the SA algorithm uses the procedure of reducing the amount of electricity spent in the operation of the plant equipment. The rate of non-condensing gas (NCG) outlet, which is harmful to the environment, can be reduced by using SA algorithm. In this way, a power plant can be operated more economically and in a more environmentally friendly manner.

Exergy-Economic-Environment Optimization of the Waste-to-Energy Power Plant Using Multi-Objective Particle-Swarm Optimization (MOPSO)

This paper brings together the benefits of the results of exergy, exergoeconomic, exergoenvironmental analysis, and ‎optimization for a waste-to-energy (WTE) power plant. Initially, exergoeconomic balances for each stream were ‎calculated. For validating the current simulations, the actual data of the Amsterdam WTE power plant in working ‎conditions were examined. Moreover, the behaviors of the influential parameters on the objective functions were ‎evaluated. In order to perform multi-objective optimization, the Multi-Objective Particle-Swarm Optimization‎ ‎‎(MOPSO) algorithm is implemented. To obtain optimum operating conditions, 14 design parameters, and 3 ‎objective functions are considered, while the total cost rate, total exergy efficiency of the cycle, and environmental ‎impacts are the objective functions. Finally, the TOPSIS decision-making method determined optimum-operating ‎conditions. The results of exergy analysis indicated that the most exergy destruction belonged to the incinerator unit ‎at 66%. Instead, the pumps contributed the least in this field, (approximately 1%). Because of the optimization ‎process, the total exergy efficiency of the power plant increased from 30.89% to 38.9% while the total cost rate was ‎‎5188.05 USD/hour. By comparison between the obtained results from the optimization procedure, introducing ‎optimum working conditions has caused an increase in exergy efficiency and reduced exergy destruction for ‎components.

Comparative analysis of compressed carbon dioxide energy storage system and compressed air energy storage system under low-temperature conditions based on conventional and advanced exergy methods

It is of great significance to determine the main source of exergy destruction for the optimal design of the high-efficiency energy storage system. In this paper, conventional exergy analysis and advanced exergy analysis methods were adopted to analyze the exergy destruction in the low-temperature Compressed Carbon dioxide Energy Storage (LT-CCES) system and low-temperature Compressed Air Energy Storage (LTA-CAES) system under the same system configuration as well as key parameters. Conventional exergy analysis is a commonly used method to show the exergy destruction in system components, while advanced exergy analysis takes into account the interactions between system components as well as the technical limitations of each component, and can get more detailed exergy destructions in system components. The results showed that, according to conventional exergy analysis, the exergy efficiency of the LT-CCES system was 56.28% and the exergy efficiency of the LTA-CAES system was 63.93%, indicating that the exergy destruction in the LT-CCES system was larger than that in the LTA-CAES system. In terms of components, the cold energy storage tank (CEST) had the largest exergy destruction, accounting for 30.97% and 32.23% of the total exergy destruction in the LT-CCES system and LTA-CAES system respectively. According to advanced exergy analysis, in both systems, the major exergy destruction in each component was the endogenous exergy destruction, implying the importance to optimize components themselves. In terms of the avoidable exergy destruction, the proportion of the CEST in the two systems were the largest (45.17% in LT-CCES and 44.51% in LTA-CAES). According to the results of conventional and advanced exergy analyses, in the LT-CCES system, CEST should be given the first priority for optimization, followed by turbine2 and compressor1, while in the LTA-CAES system, CEST should be given the first priority for optimization, followed by turbine1 and turbine2.

Exergo-sustainability indicators of a target drone engine at dynamic loads

Energy security and low environmental impact issues become hot topics due to usage of small-sized turbojet engines in many areas. In this study, thermodynamic analysis of target drone turbojet engine (TRS18) was experimentally carried out for different non-linear loads. The main goal is to reveal effects of power settings on exergetic performance of TRS18 and its components by using energy, exergy and exergo-sustainability metrics regarding the TRS18 for each load. For this aim, several input parameters related to TRS18 were measured while some of them were calculated by reverse engineering. Based on these data, energetic and exergetic computations for three components and whole engine were performed with respect to ten RPM values. According to component-based exergy results, exergy destruction of components increase due to rising RPM value. Namely, for the combustor, exergy destruction ranges from 214.46 kW to 722.54 kW whereas it changes between 12.36 kW and 98.57 kW at turbine. As for compressor, it is observed between 4.19 kW and 37.23 kW. However, increasing of RPM value affects favourably exergy efficiency of components. Namely, exergy efficiency of the combustor changes between 41.8% and 63.4% whereas that of the turbine increases from 91.9% to 96.1%. For compressor, it is observed between 83.6% and 89% through rising power settings. With respect to exergetic findings of the whole TRS18 engine, exergy efficiency of TRS18 increases 5.8%–18.07% whereas exergetic sustainability index of the engine is calculated from 0.061 to 0.22 through rising RPM values. However, exergy destruction factor of TRS18 decreases from 67.9% to 49.6% while environmental effect factor regarding the engine diminishes from 16.23 to 4.53. For thermal systems which be exposed different loads, this study could establish relationship between engine efficiency and operation load. Moreover, it could be inferred that examining sustainability aspects of TRS18 under different loads helps finding optimum operating ranges in terms of fuel consumption and environmental impact.

Parametric Assessment on the Advanced Exergy Performance of a CO2 Energy Storage Based Trigeneration System

In this paper, conventional and advanced exergy analyses are comprehensively introduced on an innovative transcritical CO2 energy storage based trigeneration system. Conventional exergy analysis can quantify in an independent way the component exergy destruction. However, the advanced technology is able to evaluate the interactions among components and identify the tangible promotion potential by allowing for the technical and economic limitations. In this method, the component exergy destruction is separated into avoidable and unavoidable parts, as well as the endogenous/exogenous parts. Calculation of the split parts is carried out by utilizing the thermodynamic cycle-based approach. Results coming from conventional exergy analysis indicate that the first three largest exergy destructions are given by cold storage, compressor 1, and heat exchanger 3. However, advanced analysis results demonstrate that the cold storage, compressor 1, and compressor 2 should be given the first improvement priority in sequence by depending on the avoidable exergy destruction. The turbine efficiency produces a higher impact on overall exergy destruction than compressor efficiency. The pinch temperature in cold storage causes the highest effect on exergy destruction amongst all the heat exchangers. There exists an optimum value in the compressor inlet pressure and ambient temperature.

Heating Performance Characteristics of an Electric Vehicle Heat Pump Air Conditioning System Based on Exergy Analysis

In this paper, a heat pump air conditioning system (HPACS) with refrigerant R134a based on the functional requirements of battery electric vehicle is designed and tested. Experiments were conducted to evaluate the effects of different ambient temperature, air flow rate of internal condenser, expansion valve (EXV) opening and compressor speed. The results demonstrate that air flow rate of internal condenser, EXV opening and compressor speed have important impact on heating capacity, compressor power consumption and coefficient of performance (COP) under several ambient temperatures. To verify the HPACS can also provide the heating capacity required by the battery electric vehicle cabin in cold climate, the system was also tested under a −5 °C ambient temperature, it was found that the heating capacity is 3.6 kW and the COP is 3.2, demonstrating that the system has high energy efficiency. In addition, heating process analysis of the HPACS under lower temperature is studied by exergy principle. The results indicate that compressor is the highest exergy destruction in all components, accounting for 55%. The percentage of exergy destruction in other components is about 28%, 12% and 5% for the expansive valve, condenser, and evaporator. Furthermore, air flow rate of internal condenser, ambient temperature and expansion valve opening have important impact on exergy destruction and exergy efficiency of the HPACS.

A novel approach in exergy optimization of a WWER1000 nuclear power plant using whale optimization algorithm

Nowadays, the scarcity of energy resources and the intensive demand of energy leads the researchers and scientists to find the efficient ways to save the energy and decrease the exergy loss. In this study, a new exergy optimization framework for a typical WWER1000 nuclear power plant (Bushehr NPP) is suggested. It is aimed to optimize the total efficiency of the power plant by decrease the exergy destruction using the first and second laws of thermodynamics. First, the main parameters of Bushehr NPP (BNPP) stream lines and exergy destruction of components are determined and the accuracy of the model is assessed. According to the analysis result, the reactor pressure vessel is the most inefficient equipment in the NPP and the steam generators are the next. Then, the exergy optimization of the steam cycle is evaluated using WOA (Whale Optimization Algorithm). To investigate the performance of the WOA, four general fitness functions are determined and compared with GA and PSO and in next exergy optimization is compared. The total exergy destruction for Bushehr power plant is decreased from 1968.9MWth to 1914.7MWth and the overall thermal efficiency of the BNPP increases from 33.66% to 36.42% using WOA. The results demonstrate that the new algorithm WOA has a proper efficiency to implement in this optimization problem.

Conventional and advanced exergy analysis of an air-cooled type of absorption-ejection refrigeration cycle with R290-mineral oil as the working pair

An absorption-ejection refrigeration cycle used R290-mineral oil mixture is investigated depending on both conventional and advanced exergy analysis. In this cycle, an ejector and an air-cooled type absorber are utilized to improve the exergetic efficiency of the system. The effects of generator temperature, condensing temperature, evaporating temperature, absorber outlet temperature, absorber efficiency, and pressure ratio on system exergetic efficiency have been discussed and compared with a single-effect absorption cycle in this study. Furthermore, the exergy destruction of each component has been calculated and analyzed. Besides, the exergy destruction of the major components are further researched through the advanced exergy analysis. Analytical results show that the absorption-ejection refrigeration cycle has a higher exergetic efficiency and a more extensive working condition range than the single effect absorption cycle and its exergetic efficiency can reach 0.3554. It is proved the R290/mineral oil as absorption refrigeration has great research value. In addition, the vast majority of exergy destruction appears in the generator and absorber, totally above 60%. The optimization of the generator has the highest priority due to its maximum endogenous avoidable exergy destruction. The absorber is in second place and its exergy destruction can be effectively reduced by optimizing other components.

Economic, Energy, Exergo-Economic, and Environmental Analyses and Multiobjective Optimization of Seawater Reverse Osmosis Desalination Systems with Boron Removal

We presented economic, energy, exergo-economic, and environmental analyses and multiobjective optimization (MOO) of seawater reverse osmosis (RO) desalination systems with boron restrictions. Exergo-economic unit cost for flows and exergy destruction for components were included. Life cycle assessment (LCA) principles with the contributions of construction and operating were introduced. An improved augmented e-constraint method was adopted for solving the MOO problems. Unnecessary iterations were avoided by bypass parameter. Results showed that the Pareto-solution with a weighting of 0.4 could provide good performances for all objective functions. The CO2 emissions reduction of 9.0% could be achieved, while the water cost is increased by 3.3%. Fixed cost dominates EUC. The environmental impact of construction is neglectable, while electricity consumption accounts for the largest share of CO2 emissions from 93.4% to 97.8%. The details of energy utilization for components, the irreversibility, and equipment...

Advanced Thermodynamic Analysis Applied to an Integrated Solar Combined Cycle System

The variation performance of integrated solar combined cycle (ISCC) is presented using energy, conventional exergy and advanced exergy analysis methods to provide information about exergy destruction of components and efficiencies of overall plant. Moreover, the theory of dividing the exergy destruction of main components into unavoidable/avoidable and exogenous/endogenous parts allows for further understanding the real potentials for improving. Besides, the exergy destruction rate and exergy efficiency of components as well as overall plant were hourly analyzed within a typical day. Results indicate the exergy destruction rate of overall system drops from 49.79% to 44.65% in summer and decreases from 49.79% to 47.59% in winter. As the solar irradiation intensity rises, the solar field efficiency reaches to 42.16% in winter and 47.5% in summer. The solar-to-electric energy efficiency gets to 13.69% in winter and 15.46% in summer. In addition, with the increase of solar energy input to the ISCC system, the exergy destruction of Brayton cycle components decreases; however, the exergy destruction of Rankine cycle components increases. Furthermore, the exergy destruction of solar field has a large extended from 14.55 MW to 58.03 MW. Moreover, the heat recovery steam generator (HRSG) and the steam turbines have the largest exergy destruction rate of 11.26% and 13.63% at 15:00 p.m.

Integrated Biomass Gasification Combined Cycle Plant for Small Scale Generation: Part B- Exergetic and Exergo-economic Analyses

This part of the paper deals with the exergetic and exergo-economic analyses of a small scale biomass integrated gasification combined cycle (BIGCC) plant. Basic configuration and operational parameters are same as those considered in Part A of the paper. Exergy analysis is conducted to analyze the component exergy destruction for identification of major exergy destroying components and for their exergy efficiency calculations. However, exergo-economic analysis investigates the effect of plant operating parameters on the fuel and product exergy cost rate(cf and cp), relative cost difference (rk), exergo-economic factor (f) and unit product cost (cp-plant) of the plants. Exergy analysis of the plant shows that an enormous amount of exergy is lost at the gasifier and at the combustion chamber. At higher TITs, exergy efficiency of the major plant components is higher, indicating a better exergetic performance of the plant at elevated TITs. Exergo-economic study indicates that the values of rk, f and unit product cost are 189.69 %, 62.13% and 0.0058 $/MJ at the base case (rp=4 & TIT=1000 °C). Also the value of these parameters increases with increase in rp, for all TITs. However, higher TIT yields in better exergo-economic performance of plant for considered range of rp values.