Thermoeconomic analysis

Keywords Latent heat storage exergy analysis, thermoeconomics, economic analysis... 

Review of an Economic Analysis Thermoeconomic Analysis Thermoeconomic Evaluation Iterative Optimization of a Thermal System Recent Developments in Thermoeconomics... 

Structural theory facilitates the evaluation of exergy cost and incorporation of thermoeconomics functional analysis (Erlach et al., 1999). It is a common formulation for the various thermoeconomic methods providing the costing equations from a set of modeling equations for the components of a system. The structural theory needs a productive structure displaying how the resource... 

Thermoeconomics of LHS systems involve the use of principles from thermodynamics and fluid mechanics and heat transfer. Therefore, thermoeconomics may be applied to both the use of those principles and materials, construction, and mechanical design, and a part of conventional economic analysis. The distinguished side of it comes from the ability to account the quality of energy and environmental impact of energy usage in economic considerations. 

This analysis considers the three basic components of a seasonal LHS system (Figure 25) constructed after one year. Table 7 shows the data used in thermoeconomic analysis. 

TABLE 7. A typical data used for thermoeconomic analysis of seasonal heat storage system... 

Domanski, R., and Fellah, G., 1998, Thermoeconomic analysis of sensible heat, thermal energy storage systems, Applied Thermal Eng. 18 693—704. 

Tsataronis, G., 1993, Thermoeconomic analysis and optimization of energy systems, Progess Energy Comb. Sys. 19 227—257. 

Chen, J. and Wu, C., Thermoeconomic analysis on the performance characteristics of a multi-stage irreversible combined heat pump system. ASME Journal of Energy Resources Technology, 122(4), 212-216, 2000. 

The resultis given inFigure 13.7 for an assumed ratio of T0/T, = 0.5, that is, an ordinary power station. For a renewable fuel / is close to 0 and the optimal efficiency is 0.3 as opposed to the Carnot value of 0.5. For a costly nonrenewable fuel such as natural gas with/ = 0.5 (i.e., 50% of all costs are spent on fuel), the optimal efficiency is 0.35, so around 15% better, although possible environmental costs related to the emission of waste have been ignored (although we should not exclude environmental costs for renewable fuel beforehand). Figure 13.8 depicts how the situation improves when Tu the temperature of the heat source, increases. Nevertheless, the trend that nonrenewable fuels are more favorable appears to persist, however, under the same restriction as just mentioned. By the way, this optimum, which we call the economic optimum, is also known as the thermoeconomic optimum and the analysis with which it was obtained is known as thermoeconomic analysis. 

This paper presents a thermodynamic availability analysis of an important process design problem, namely, the synthesis of networks of exchangers, heaters and/or coolers to transfer the excess energy from a set of hot streams to streams which require heating (cold streams). Emphasis is placed on the discussion of thermodynamic and economic (i.e., thermoeconomic) aspects of two recent methods for the evolutionary synthesis of energy-optimum and minimum-cost networks. These methods include the... 

The thermoeconomic approach of Pehler and Liu (1 ) is based on both thermodynamic and economic considerations of the network synthesis problem. It consists of four steps. The detailed descriptions of the first two steps can be found from the references cited below. In this paper, some emphasis is placed on the thermodynamic availability analysis of the third and fourth steps which include practical heuristic and evolutionary rules for the systematic synthesis of energy-optimum and... 

The preceding analysis provides the thermodynamic basis of a similar stream matching rule described in Corollary 3 of reference no. 4. In the thermoeconomic approach, the thermodynamic matching rule is not only applied in the initial generation of an energy-optimum and nearly minimum-cost network, but also in the evolutionary synthesis of an energy-optimum and minimum-cost network. 

Thermoeconomic Analysis of Feasibility Rules of Linnhoff and Flower... 

Based on the preceding analysis, it is evident that out of the ten feasibility rules of Linnhoff and Flower, only three of them (nos. 1 and 2, the inverse form of no. 8) may find some applications in the evolutionary improvement of a thermodynamically-based initial network such as that synthesized by steps 1 to 3 of the thermoeconomic approach. The remaining majority of the feasibility rules would rarely be applicable, as the placement of units in thermodynamically efficient positions can be assured in the generation of an initial network through the use of the thermodynamic matching rule. Consequently, only two of the feasibility rules (nos. 1 and 2) of Linnhoff and Flower have been adapted as Rule 2a in the thermoeconomic approach. 

Thermoeconomic optimization using differentially derived prices, permitting the analysis of the system s local and global responses to well specified small changes in the state of the system, and leading to sensitivity analysis and optimization techniques. 

Both modes of thermoeconomic analysis, accounting and optimization, are illustrated in example 2, considering a cost criterion function. The case of an energy criterion function may be included as a special case. 

Tribus, M. and El-Sayed, Y., "Thermoeconomic Analysis of an Industrial Process", report, Center for Advanced Engineering Study, MIT, Cambridge, MA... 

The concept of essergetic functional analysis is introduced as a tool for approaching a condition known as "thermoeconomic isolation" of the interdependent equipment components of a system or process. If an interdependent component is thermo-economically isolated, then that component may be suboptimized with respect to many new, underlying variables. The required essergy analysis procedures are illustrated by considering the synthesis and design of components of a large steam power plant. 

It remains to be shown whether or not the three requirements of essergetic functional analysis are always consistent with proven thermoeconomic decomposition techniques such as El-Sayed s method of Lagrange multipliers. It could be that the proof of this consistency could only be obtained at the expense of new, stringent conditions upon the definition of the utilization functions needed to guarantee compliance with these three requirements. 

Evans, R.B. "Thermoeconomic Isolation and Essergy Analysis." Energy The International Journal, 5, 805, 1980. 

El-Sayed, Y.M. and Tribus M. Strategic Use of Thermoeconomic Analysis for Process Improvement. This Volume. 

The basis of any thermoeconomic analysis is the application of a money balance to the system or subsystem of interest... 

Equations 33-35 are the basic thermoeconomic governing equations for the Second Law based optimization. It should be noted that although column entropy productions due to heat transfer are neglected, the analysis nevertheless includes the fact that the column "buys" thermal available-energy from the reboiler in the thermoeconomic governing equations. 

El-Sayed, Y. M. and Tribus, M., "A Specific Strategy for the Improvement of Process Economics through Thermoeconomic Analysis," In reference 18, p. 278 (1981). 

El-Sayed, Y. M. and Aplenc, A. J., "Application of the Thermoeconomic Approach to the Analysis and Optimization of Vapor-Compression Desalting System," Trans. ASME J. Eng. Power, 92, 17 (1970). 

Here, exm is the flow-exergy destruction, or irreversibility, and T0 the reference temperature. The system will be thermodynamically advantageous only if the Nx is less than unity. The exergy destruction number is widely used in second-law-based thermoeconomic analysis of thermal processes such as heat exchangers. 

The thermoeconomics of the latent heat storage system involves fixed capital investment, operational and maintenance cost, and exergy costs. The total fixed capital investment consists of (i) direct expenses, which are equipment cost, materials, and labor, (ii) indirect project expenses, which are freight, insurance, taxes, construction, and overhead, (iii) contingency and contractor fees, and (iv) auxiliary facilities, such as site development and auxiliary buildings. Table 5.7a shows the data used in the thermoeconomic analysis. 

Considering that the main discussion nowadays is about the prices of the electricity surplus from bagasse-origin cogeneration, this paper intends to evaluate these figures using Thermoeconomic Analysis concepts. 

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