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  2. Exergy - Wikipedia

    en.wikipedia.org/wiki/Exergy

    Note that the exergy flux of graybody radiation can be a small fraction of the energy flux. For example, the ratio of exergy flux to energy flux (/) for graybody radiation with emissivity = is equal to 40.0%, for = and = (=). That is, a maximum of only 40% of the graybody energy flux can be converted to work in this case (already only 50% of ...

  3. Exergy efficiency - Wikipedia

    en.wikipedia.org/wiki/Exergy_efficiency

    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.

  4. Energy quality - Wikipedia

    en.wikipedia.org/wiki/Energy_quality

    Energy quality is a measure of the ease with which a form of energy can be converted to useful work or to another form of energy: i.e. its content of thermodynamic free energy. A high quality form of energy has a high content of thermodynamic free energy, and therefore a high proportion of it can be converted to work; whereas with low quality ...

  5. Fundamental thermodynamic relation - Wikipedia

    en.wikipedia.org/wiki/Fundamental_thermodynamic...

    Thus, they are essentially equations of state, and using the fundamental equations, experimental data can be used to determine sought-after quantities like G (Gibbs free energy) or H . [1] The relation is generally expressed as a microscopic change in internal energy in terms of microscopic changes in entropy , and volume for a closed system in ...

  6. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    Energy converter is an example of an energy transformation. For example, a light bulb falls into the categories energy converter. η = P o u t P i n {\displaystyle \eta ={\frac {P_{\mathrm {out} }}{P_{\mathrm {in} }}}} Even though the definition includes the notion of usefulness, efficiency is considered a technical or physical term.

  7. Energy return on investment - Wikipedia

    en.wikipedia.org/wiki/Energy_return_on_investment

    The issue is still subject of numerous studies, and prompting academic argument. That's mainly because the "energy invested" critically depends on technology, methodology, and system boundary assumptions, resulting in a range from a maximum of 2000 kWh/m 2 of module area down to a minimum of 300 kWh/m 2 with a median value of 585 kWh/m 2 according to a meta-study from 2013.

  8. Gibbs–Helmholtz equation - Wikipedia

    en.wikipedia.org/wiki/Gibbs–Helmholtz_equation

    which relates the Gibbs energy to a chemical equilibrium constant, the van 't Hoff equation can be derived. [ 9 ] Since the change in a system's Gibbs energy is equal to the maximum amount of non-expansion work that the system can do in a process, the Gibbs-Helmholtz equation may be used to estimate how much non-expansion work can be done by a ...

  9. State function - Wikipedia

    en.wikipedia.org/wiki/State_function

    In the thermodynamics of equilibrium, a state function, function of state, or point function for a thermodynamic system is a mathematical function relating several state variables or state quantities (that describe equilibrium states of a system) that depend only on the current equilibrium thermodynamic state of the system [1] (e.g. gas, liquid, solid, crystal, or emulsion), not the path which ...