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The exergy destruction of a cycle is the sum of the exergy destruction of the processes that compose that cycle. The exergy destruction of a cycle can also be determined without tracing the individual processes by considering the entire cycle as a single process and using one of the exergy destruction equations.
The destruction of exergy is closely related to the creation of entropy and as such any system containing highly irreversible processes will have a low energy efficiency. As an example the combustion process inside a power stations gas turbine is highly irreversible and approximately 25% of the exergy input will be destroyed here.
The exergy of the system is the maximal amount of useful work that the system can generate, during a process which brings it to equilibrium with its environment, or the amount of energy available. During an irreversible process, such as heat exchanges with reservoirs, exergy is destroyed.
It gives an upper bound on the power that can be derived from a real process that is lower than that predicted by Carnot for a Carnot cycle, and accommodates the exergy destruction occurring as heat is transferred irreversibly. It is also called finite-time thermodynamics, entropy generation minimization, or thermodynamic optimization. [1]
Second law analysis is valuable in scientific and engineering analysis in that it provides a number of benefits over energy analysis alone, including the basis for determining energy quality (exergy content [66] [67] [68]), understanding fundamental physical phenomena, and improving performance evaluation and optimization. As a result, a ...
Most people enter military service “with the fundamental sense that they are good people and that they are doing this for good purposes, on the side of freedom and country and God,” said Dr. Wayne Jonas, a military physician for 24 years and president and CEO of the Samueli Institute, a non-profit health research organization.
Copper is emerging as the next indispensable industrial commodity, mirroring oil's rise in earlier decades, a top commodities analyst said. This time around, new forces in the economy, namely the ...
Other human-caused effects (such as changes to albedo, or loss of evaporative cooling) that might contribute to urban heat islands are not considered to be anthropogenic heat by this definition. Anthropogenic heat is a much smaller contributor to global warming than greenhouse gases are. [20]