the overall exergy is the sum of
- Potencial Exergy
- Kinetics Exergy
- Physical Exergy
- Chemical Exergy
The physical exergy associated with a thermodynamic system is given by
EsysPH =(U-U0)+p0(V-V0)-T0(S-S0)
where U V, and S represent the internal energy, volume and entropy of the system, respectively. The subscript 0 denotes the state of the same system at the temperature T0 and pressure P0 of the environment. The rate of physical exergy EsysPH associated with a material stream (subscript ms) is
📷
The physical exergy of a system consists of thermal exergy 📷(due to system temperature) and mechanical exergy ME (due to system pressure):
📷
Dear Saad, thanks a lot for useful answer. from your response, the physical exergy is the thermal exergy or the net work work from heat transfer and the work from pressure variation in the system.
thanks again
Hi
Physical exergy is equal to the maximum amount of work obtainable when the stream of substance is brought from its initial state to the environmental state defined by Po and To, by physical processes involving only thermal interaction with the environment.
The physical exergy of a stream of substance is naturally divisible into two components. Consider a pair of hypothetical reversible processes; an isobaric process taking place at the initial pressure followed by an isothermal process corresponding to the environmental temperature To.
for more information please see
Kotas, Tadeusz Jozef. The exergy method of thermal plant analysis. Elsevier, 2013.
it is a combined property between the system and the environment
for more deatiles about the exergy it is recommended to follow the the textbook for Yunus A. Cengel "
Thermodynamics: An Engineering Approach"
The attempts to quantify the quality or “work potential” of energy in the light of the second law of thermodynamics has resulted in the definition of the exergy property. The useful work potential of a given amount of energy at a specified state is called exergy. It is also called the availability or available energy. The work potential of the energy contained in a system at a specified state, relative to a reference (dead) state, is simply the maximum useful work that can be obtained from the system .
Efficiency Evaluation of Energy Systems
By Mehmet Kanoğlu, Yunus A. Çengel, Ibrahim Dincer
Dear doctors I'm thankful for your useful answer where I can understand that the physical exergy is the net work given from variation of temperature and pressure between the system and its environment. Do you have agree ?
the exergy of a system is the maximum useful work possible during a process that brings the system into equilibrium with a environment. where the physical exergy is given by :
Eph= (u - u0) + P0(v - v0) - T0(s - s0)
Entropy: A concept that is not a physical quantity
https://www.researchgate.net/publication/230554936_Entropy_A_concept_that_is_not_a_physical_quantity
Dear @ Shfeng Zhang, thanks a lot for sharing your paper. I find it very interesting
Good question.. Please share me the best answer might you trust...
Regards…
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