Exergy method of energy systems analysis

Book · Tue Jan 01 00:00:00 EST 1980

OSTI ID:6148569

Ahern, J E

This book presents a practical approach for applying the second law of thermodynamics to energy-related systems. The approach has been used extensively in the Soviet Union and in Europe. (The appendix includes translations of Russian papers that discuss applications of the approach). Why this concern for the second law. Energy-related systems commonly have been designed and evaluated using first law heat balances. But such calculations neglect the variation in the quality of the energy throughout a system. As a result, losses and inefficiencies are not evaluated realistically. Therefore, effective energy-conservation measures and improvements in system performance and efficiency cannot be accomplished by the heat-balance method alone. Something more is required. In the method for evaluating an energy-related system described in this book, the quality of the energy at any point in the system is determined. This value, called exergy, is the actual amount of work that can be performed by a fluid or mass relative to a zero exergy or a state reference condition. The exergy method shows the real changes in the work of the system, process by process. Losses then can be assessed after the useful work can be accounted for. Data already available from conventional first-law heat balance provide input to exergy calculations. The method of analysis is described by a system analysis approach - used for preliminary evaluation and for single analyses using calculators or computers without iterative cases - and by a process block approach that is advantageous for computer analysis of system designs when parametric evaluations are made.

• OSTI ID: 6148569
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
29 ENERGY PLANNING
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ENERGY CONSERVATION
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CALCULATION METHODS
ENERGY
420400* - Engineering- Heat Transfer & Fluid Flow
290100 - Energy Planning & Policy- Energy Analysis & Modeling
291000 - Energy Planning & Policy- Conservation