What is chemical exergy?

Chemical exergy is defined as the maximum work potential obtainable by taking the mass flow from the ambient state to the dead state. From: Handbook of Natural Gas Transmission and Processing (Fourth Edition), 2019.

What is exergy formula?

The exergy destruction and entropy generation are related by the following expression: E x d = T 0 Δ S g e n , where T0 is the reference temperature. If E x d > 0 , then the process is irreversible; if E x d = 0 , then the process is reversible; if E x d < 0 , the process is impossible.

What is difference between exergy and entropy?

The entropy of a system is only related to the state of the system and is unrelated to the environment; in contrast, the exergy of a system is not only related to the state of the system but also related to the state of the environment, making it too complicated.

What is an example of exergy?

During this time it was usually called availability or available work. As a simple example of exergy, air at atmospheric conditions of temperature, pressure, and composition contains energy but no exergy when it is chosen as the thermodynamic reference state known as ambient.

What is difference between energy and exergy?

The main important difference between energy and exergy: energy is conserved, while exergy, a measure of energy quality or work potential, can be consumed.

What is physical exergy?

Physical exergy is defined as the maximum work potential obtainable by taking the mass stream at thermal and mechanical equilibrium with the environment (Querol et al., 2012). From: Handbook of Natural Gas Transmission and Processing (Fourth Edition), 2019.

What is exergy in thermodynamics?

Exergy (Ex) is defined as the amount of work (=entropy-free energy) a system can perform when it is brought into thermodynamic equilibrium with its environment, i.e. lAmax l=Ex (Jørgensen et al., 1999). From: Towards a Thermodynamic Theory for Ecological Systems, 2004.

How is exergy different from energy?

Energy is based on the first law of thermodynamics and gives the quantity of energy only. While exergy is based on the second law of thermodynamics and represents the quality of energy and involves the irreversibility while analysing system efficiency.

What do you mean by exergy?

Exergy is defined as the amount of work (= entropy-free energy) a system can perform when it is brought into thermodynamic equilibrium with its environment (Figure 1).

Can exergy be greater than energy?

In this condition the system input energy is the fuel energy and not a distinguished value of Q_h. And it is clear the exergy of fuel is a bit higher than of its energy. Therefore the exergy efficiency will be less than the energy efficiency.

What is the difference between exergy and free energy?

Exergy represents the maximum amount of work that can be extracted from a system going in equilibrium with its environment, while the Gibbs Free Energy is evaluated at T,P of the system in equilibrium with the environment.

Why is exergy important?

Exergy analysis permits many of the shortcomings of energy analysis to be overcome. Exergy analysis, by stemming from the second law of thermodynamics, is useful in identifying the causes, locations, and magnitudes of process inefficiencies.