Academic literature on the topic 'Exergoeconomic analysis'

Detailed thermodynamic, exergoeconomic, and multi-objective analysis are performed for a supercritical recompression Brayton cycle in which the advanced working medium mixture of nitrous oxide and helium (N2O–He) is utilized for power generation. The thermodynamic and exergoeconomic models are propitious based on the standard components’ mass and energy conservation, exergy balance equation, and exergy cost calculation equation. An investigation of the sensitivity parametric is considered for judging the impact of crucial decision variable parameters on the performance of the proposed Brayton cycle. The proposed cycle’s performance is evaluated by systematic analysis of the thermal efficiency (ηth), exergy efficiency (ηex), total cost rate (C.total), levelized cost of electricity (LCOE), and the total heat transfer area (Atotal). Furthermore, multi-objective optimization is adopted from the viewpoint of the first and second laws of exergoeconomics to find the optimum operating parameters and to improve the circular’s exergoeconomic performance. The final results illustrate that the optimization calculation is based on the fact of the exergoeconomics method; the whole system produces electrical power of 0.277 MW with C.total of USD 18.37/h, while the ηth, ηex, Atotal, and LCOE are 49.14%, 67.29%, 165.55 m2 and USD 0.0196/kWh, respectively. It is concluded that the work exergy destruction for the reactor and turbine is higher than that of other components; then, after the multi-objective optimization analysis, the ηth and ηex improved by 2.08% and 5.07%, respectively, and the C.total, Atotal, and LCOE decreased by 13.99%, 0.01%, and 5.13%, respectively.

Polygeneration energy systems have been widely accepted because of their superiority over conventional stand-alone plants in energy efficiency and emissions control. Coal-based polygeneration system, especially producing methanol and electricity, will play an important role in Chinese sustainable developing energy system. Researches indicate that the parallel polygeneration system producing methanol and electricity with CO-riched gas once through (PCGOT) has higher comprehensive profitability and higher reliability, but the systemic and objective evaluation to PCGOT is lacking. In this paper, the matrix mode exergoeconomic method is adopted to analyze the PCGOT. Some indices, such as exergy cost coefficient, unit exergoeconomic cost, cost difference and exergoeconomic coefficient, etc. are calculated and analyzed by using exergoeconomics theory. Based on the analysis, the direction for further improvement is pointed out, and the energy flows with different qualities in different parts of system are given the rationally fixed prices. The calculated electricity cost is 0.22RMB/ (kW•h) and methanol cost 1118RMB/t while coal price is 500 RMB/t. In addition, the coal price sensitivity analysis is conducted, the results show that when the coal price reaches 800RMB/t, the electricity cost is higher than Shanxi province average on-grid power tariff 0.304RMB/ (kW•h) in 2011, when the coal price reaches 1000RMB/t, the methanol cost is higher than methanol factory prices 2000RMB/t at present.

The improvement of the design and operation of energy conversion systems is a theme of global concern. As an energy intensive operation, industrial agricultural product drying has also attracted significant attention in recent years. Taking a novel industrial corn drying system with drying capacity of 5.5 t/h as a study case, based on existing exergoeconomic and exergetic analysis methodology, the present work investigated the exergetic and economic performance of the drying system and identified its energy use deficiencies. The results showed that the average drying rate for corn drying in the system is 1.98 gwater/gdry matter h. The average exergy rate for dehydrating the moisture from the corn kernel is 345.22 kW and the exergy efficiency of the drying chamber ranges from 14.81% to 40.10%. The average cost of producing 1 GJ exergy for removing water from wet corn kernels is USD 25.971, while the average cost of removing 1 kg water is USD 0.159. These results might help to further understand the drying process from the exergoeconomic perspective and aid formulation of a scientific index for agricultural product industrial drying. Additionally, the results also indicated that, from an energy perspective, the combustion chamber should be firstly optimized, while the drying chamber should be given priority from the exergoeconomics perspective. The main results would be helpful for further optimizing the drying process from both energetic and economic perspectives and provide new thinking about agricultural product industrial drying from the perspective of exergoeconomics.

This paper proposes an exergoeconomic analysis method that considers environmental costs to make up for the lack of description of environmental costs in the traditional matrix model exergoeconomic analysis method. This method tracks the formation process of the product cost through life cycle and makes a useful exploration for revealing the true cost of the system product. According to actual needs, the principles for the construction of environmental emissions of products are proposed, and a detailed exergoeconomic analysis model is established by taking the iron smelting system as an example. Through calculation and analysis, the formation process and change rule of unit exergoeconomic cost of products in the system are revealed. Especially, considering the exergoeconomic cost of carbon emissions, the results show that the three most influential substances are sinter, coke, and pellets. When carbon dioxide emissions are considered, the total cost will increase by 165.3 CNY/t iron, and unit exergoeconomic cost gradually increases with the progress of the production process.

Existing methods of exergoeconomic analysis and optimization of energy systems operate with single average or marginal cost values per exergy unit for each material stream in the system being considered. These costs do not contain detailed information on (a) how much exergy, and (b) at what cost each exergy unit was supplied to the stream in the upstream processes. The cost of supplying exergy, however, might vary significantly from one process step to the other. Knowledge of the exergy addition and the corresponding cost at each previous step can be used to improve the costing process. This paper presents a new approach to exergy costing in exergoeconomics. The monetary flow rate associated with the thermal, mechanical and chemical exergy of a material stream at a given state is calculated by considering the complete previous history of supplying and removing units of the corresponding exergy form to and from the stream being considered. When exergy is supplied to a stream, the cost of adding each exergy unit to the stream is calculated using the cost of product exergy unit for the process or device in which the exergy addition occurs. When the stream being considered supplies exergy to another exergy carrier, the last-in-first-out (LIFO) principle of accounting is used for the spent exergy units to calculate the cost of exergy supply to the carrier. The new approach eliminates the need for auxiliary assumptions in the exergoeconomic analysis of energy systems and improves the fairness of the costing process by taking a closer look at both the cost-formation and the monetary-value-use processes. This closer look mainly includes the simultaneous consideration of the exergy and the corresponding monetary values added to or removed from a material stream in each process step. In general, the analysis becomes more complex when the new approach is used instead of the previous exergoeconomic methods. The benefits of using the new approach, however, significantly outweigh the increased efforts. The new approach, combined with some other recent developments, makes exergoeconomics an objective methodology for analyzing and optimizing energy systems.

This study is part 2 of the investigation on the exergetic and exergoeconomic parameters of an existing system with an air-to-water heat pump unit as a heat source. Part 1 presents the used experimental setup. The main aim of the conducted experimental tests is to develop models of produced heat rate and energetic COP at different ambient conditions. The obtained data is used in Part 2 of the study where the exergetinc and exergoeconomic assessment is carried out. The exergetic and exergoeconomic analysis was performed at dynamically changing ambient parameters. The considered operation modes of the air-to-water heat pump (AWHP) unit and backup heater (BUH) were evaluated based on Seasonal Exergetic Efficiency. For the exergoeconomic analysis, the SPECO method is used. Thus, this paper provides an exhaustive understanding of the exergy and exergoeconomic performance of the considered air-to-water heat pump system.

A direct expansion solar assisted heat pump (DX-SAHP) is a heating water technology that convey a conventional solar heating system with a heat pump. This technology with great potential should overcome economics aspects to be available commercially soon. An exergoeconomic analysis of a DX-SAHP has been performed for three collector configurations and three compressor displacement capacity under the meteorological condition of Portoviejo city in Ecuador, a location with a tropical and humid climate. The present work is aimed to study the relationship between exergoeconomic data under various operations conditions. In addition, the exergy destruction, exergetic efficiency, cost rate per exergy unit product and fuel, cost rate associated to exergy destruction, exergoeconomic factor for each component of a DX-SAHP are evaluated. The exergoeconomic factor is found lowest for the solar collector for all the configurations, with estimated values of 5 to 21%. The component that needs more improvement for a tropical and humid climate is the solar collector based on exergoeconomic factor. On the basis of the present study, it can be concluded that a solar collector area of 1,5 m2 and a rotational displacement capacity of 1350 rpm performs better in all respects.

This study presents four analysis at unit 4 Kamojang geothermal power plant are exergy analysis at current condition, exergy efficiency optimization, economic optimization, and exergoeconomic optimization with wellhead valve pressure as a variable. Calculations are conducted by using the MATLAB. Thermodynamics characteristic of geothermal fluid assumed as water characteristic which get from REFPROP. Wellhead pressure operational condition 10 bar has exergy efficiency 31.91%. Exergy efficiency optimization has wellhead valve pressure 5.06 bar, exergy efficiency 47.3%, and system cost US$ 3,957,100. Economic optimization has well pressure 11 bar, exergy efficiency 22.13%, and system cost US$ 2,242,200. Exergoeconomic optimization has 15 optimum condition. Exergoeconomic optimization aims to analyze the optimum wellhead valve pressure for maximum exergy efficiency and minimum cost of power plant system.

The performance evaluation and optimization of an energy conversion system design of an energy intensive drying system applied the method of combining exergy and economy is a theme of global concern. In this study, a gas-type industrial drying system of black tea with a capacity of 100 kg/h is used to investigate the exergetic and economic performance through the exergy and exergoeconomic methodology. The result shows that the drying rate of tea varies from the maximum value of 3.48 gwater/gdry matter h to the minimum 0.18 gwater/gdry matter h. The highest exergy destruction rate is found for the drying chamber (74.92 kW), followed by the combustion chamber (20.42 kW) in the initial drying system, and 51.83 kW and 21.15 kW in the redrying system. Similarly, the highest cost of the exergy destruction rate is found for the drying chamber (18.497 USD/h), followed by the combustion chamber (5.041 USD/h) in the initial drying system, and 12.796 USD/h and 5.222 USD/h in the redrying system. Furthermore, we analyzed the unit exergy rate consumed and the unit exergy cost of water removal in different drying sections of the drying system, and determined the optimal ordering of each component. These results mentioned above indicate that, whether from an energy or economic perspective, the component improvements should prioritize the drying chamber. Accordingly, minimizing exergy destruction and the cost of the exergy destruction rate can be considered as a strategy for improving the performance of energy and economy. Overall, the main results provide a more intuitive judgment for system improvement and optimization, and the exergy and exergoeconomic methodology can be commended as a method for agricultural product industrial drying from the perspective of exergoeconomics.