• Journal of Energy Engineering
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• v.29 no.2
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• pp.40-60
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• 2020

When various kinds of products are produced from a single energy system, the methodology which allocates the common cost to each product cost is very important because it is directly related with the profit and loss of producer and purchaser. In the cost allocation methodology of electricity and heat for CHP, there are heat method, work method, benefit distribution method, exergy method, and so on. Benefit distribution method is the most widely known worldwide, and exergy method is widely recognized among thermal engineers. As a result of review, it is judged that the rationality of benefit distribution method is low because the result deviates from common sense, and the rationality of exergy method is high because the result consistent with common sense. In accounting, it is calculated as merit methodology and the result is used for negotiations between producer and buyer, but In thermal engineering, the rationality of exergy methodology is described only as a thesis. The purpose of this study is to compare and examine the rationality of merit methodology and exergy methodology, and the aim is to describe in detail in order that producer and buyer can understand the rationality of each methodology.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.222-227
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• 2000

At representative thermoeconomic theory to determine the unit cost of multiple products, there are the $\ulcorner$SPECO$\lrcorner$ method of Tsatsaronis's study group and the $\ulcorner$MOPSA$\lrcorner$ method of chung-ang university phase laboratory. Against this theory, we propose new theory called $\ulcorner$Thermoeconomics to divide the exergetic cost into each working fluid$\lrcorner$ in this study. Also, we apply new thermoeconomic theory to CGAM problem (30MW-grade imaginary gas turbine cogeneration power plant) that it is representative power system in thermoeconomics theory, and we fixed to interpreted the unit cost of electricity on the part of gas turbine and the unit cost of steam exergy(enthalpy) on the part of HRSG.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.871-878
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• 2000

Exergetic and thermoeconomic analysis were performed for a 500-MW combined cycle plant and a 137-MW steam power plant without decomposition of exergy stream of matter into thermal and mechanical exergies. The calculated costs of electricity are almost same within 0.5% as those obtained by the thermoeconomic method with decomposition of exergy into thermal and mechanical exergies of the combined cycle plant. However for the gas-turbine cogeneration plant having different kinds of products. the difference in the unit costs of products, obtained from the two methodologies is about 2%. Such outcome indicates that the level at which the cost balances are formulated does not affect the result of thermoeconomic analysis, that is somewhat contradictory to that concluded previously.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.677-687
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• 2021

The tendency to renewables is one of the consequences of changing attitudes towards energy issues. As a result, solar energy, which is the leader among renewable energies based on availability and potential, plays a crucial role in full filing global needs. Significant problems with the solar thermal power plants (STPP) are the operation time, which is limited by daylight and is approximately half of the power plants with fossil fuels, and the capital cost. Exergy analysis survey of STPP hybrid with PCM storage carried out using Engineering Equation Solver (EES) program with genetic algorithm (GA) for three different scenarios, based on eight decision variables, which led us to decrease final product cost (electricity) in optimized scenario up to 30% compare to base case scenario from 28.99 $/kWh to 20.27 $/kWh for the case study. Also, in the optimal third scenario of this plant, the inner carbon dioxide gas cycle produces 1200 kW power with a thermal efficiency of 59% and also 1000 m3/h water with an exergy efficiency of 23.4% and 79.70 kg/h with an overall exergy efficiency of 34% is produced in the tetrageneration plant.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.360-371
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• 2003

The calculation of each unit cost of productions is very important for evaluating the economical efficiency and deciding the reasonable sale price. In the present, two methods of exergy costing on multiple energy systems are suggested to reduce the complexities of conventional SPECO method and MOPSA method and to improve the calculation efficiency of exergoeconomics. The suggested methods were applied to a gas-turbine cogeneration and the unit costs of the power and the steam energy were calculated as an example. The main points of our methods are the following three. First, one exergetic cost is applied to one cycle or system. Second, the suggested equations are the internal cost balance equation and the production cost balance equation. Third, necessary states in a system are only inlet and exit states of 1ha components producing energy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.9
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• pp.624-630
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• 2008

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, exergetic methods, and so on. On the other hand, we have proposed a worth method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied worth method to a steam-turbine cogeneration which produces 22.2 MW of electricity and 44.4 Gcal/h of heat, and then we allocated 2,578 $/h of common cost to electricity cost and heat cost. Also, we compared with various cost allocation methods. As the result, we conclude that exergy of various kinds of worth basis evaluates the worth of heat and electricity most reasonably on this system.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.351-356
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• 2008

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, various exergetic methods, and so on. On the other hand, we have proposed a worth evaluation method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied this methodology to a gas-turbine cogeneration which produces 119.2 GJ/h of electricity and 134.7 GJ/h of heat, and then we allocated 3,150 $/h of fuel cost to electricity cost and heat cost. Also, we compared with various cost allocation methods. As the result, we conclude that exergy of various kinds of worth basis evaluates the worth of heat and electricity most reasonably on this system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.76-83
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• 2003

Exergetic and thermoeconomic analyses were performed fer a 137-MW steam power plant. In these analyses, mass and energy conservation laws were applied to each component of the system. Quantitative balance of the exergy and exergetic cost for each component, and for the whole system was carefully considered. The exergo-economic model, which represented the productive structure of the system was used to visualize the cost formation process and the productive interaction between components. The computer program developed in this study can determine production costs of power plants, such as gas-and steam-turbines plants and gas-turbine cogeneration plants. The program can also be used to study plant characteristics, namely, thermodynamic performance and sensitivity to changes in process and/or component design variables.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.27-35
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• 2019

In order to solve the global warming and reduce greenhouse gas emissions, $CO_2$ capture technology was developed by applying oxy-fuel combustion. But there has been such a problem that its economic efficiency is low due to the high price of oxygen gases. ASU is known to be most suitable method to produce large quantity of oxygen, to reduce the oxygen production cost, the efficiency of ASU need to be improved. To improve the efficiency of ASU, exergy analysis can be used. The exergy analysis provides the information of used energy in the process, the location and size of exergy destruction. In this study, the exergy analysis was used for process developing and optimization of large scale ASU. The process simulation of ASU was conducted, the results were used to calculate the exergy. As a result, to reduce the exergy loss in the cold box of ASU, a lower operating pressure process was suggested. It was confirmed the importance of heat leak and heat loss reduction of cold box. Also, the unit process of ASU which requires thermal integration was confirmed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.7
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• pp.673-682
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• 2004

The cost accounting of products on energy system is important for evaluating the economical efficiency and deciding the reasonable sale price. In the present, the suggested OECOPC method was applied to a combined cycle cogeneration, and each unit cost of electricity and heat products was calculated. In addition, the previous thermoeconomic methods were applied and calculated to equal system. As a result of comparing various methods, the unit costs by OECOPC method were calculated in the middle value of those. This result tells that OECOPC methods are most moderate. The suggested OECOPC method can apply any energy system. Hence this method is expected to make contribution to cost accounting on energy System.