Abstract
Starting from the fact that the problem of the loss of technical work of exit gases in a boiler stack involves the state of thermodynimc imbalance, this paper gives a derivation of a suitable analytic relation for determining the maximum technical work, or exergy, which is equivalent to the lost technical work in exit gases. This serves as the basis for solving the suitable equivalent thermodynamic process which confirms the premiss of the problem.
In order to observe the problem in its full range, the process involved was represented both in a work p-v diagram, a heat T-s diagram, as well as in an h-s diagram.
The exergy function analysis was conducted according to the most influential parameter, whereas flue gases(exit gases) were considered as semi-perfect, due to the fact that this definition corresponds better to the real situation.
With the aim to give a full insight into the subject matter in the sense of quantity, in the end the authors determined the power of an imaginary reversible machine which would operate under the same conditions and parameters, and which would use these gases until they become balanced with the environment.
The concept of exergy developed on the basis of a general model for determining the loss of technical work in exit gases of boiler stacks was illustrated by a practical calculation example.
Key words: maximum technical work (exergy), exit gases, boiler stack, work and heat diagram, h-s diagram, reversible processes, graph methods.
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