Energetics

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Definition

From the Wikipedia:

"Energetics is the scientific study of energy flows and storages under transformation. Because energy flows at all scales, from the quantum level, to the biosphere and cosmos, energetics is therefore a very broad discipline, encompassing for example thermodynamics, chemistry, biological energetics, biochemistry and ecological energetics. Where each branch of energetics begins and ends is a topic of constant debate." (http://en.wikipedia.org/wiki/Principles_of_energetics#Principles_of_energetics)

Principles

From Howard Thomas Odum:

  • Zeroth principle of energetics

If two thermodynamic systems A and B are in thermal equilibrium, and B and C are also in thermal equilibrium, then A and C are in thermal equilibrium.


  • First principle of energetics

The increase in the internal energy of a system is equal to the amount of energy added to the system by heating, minus the amount lost in the form of work done by the system on its surroundings.


  • Second principle of energetics

The total entropy of any isolated thermodynamic system tends to increase over time, approaching a maximum value.


  • Third principle of energetics

As a system approaches absolute zero of temperature all processes cease and the entropy of the system approaches a minimum value or zero for the case of a perfect crystalline substance.


  • Fourth principle of energetics

There seem to be two opinions on the fourth principle of energetics:

o The Onsager reciprocal relations are sometimes called the fourth law of thermodynamics. As the fourth law of thermodynamics Onsager reciprocal relations would constitute the fourth principle of energetics.

o In the field of ecological energetics H.T. Odum considered maximum power, the fourth principle of energetics. Odum also proposed the Maximum empower principle as a corollary of the maximum power principle, and considered it to describe the propensities of evolutionary self-organization.


  • Fifth principle of energetics

The energy quality factor increases hierarchically. From studies of ecological food chains, Odum proposed that energy transformations form a hierarchical series measured by Transformity increase (Odum 2000, p. 246). Flows of energy develop hierarchical webs in which inflowing energies interact and are transformed by work processes into energy forms of higher quality that feedback amplifier actions, helping to maximise the power of the system" — (Odum 1994, p. 251)


  • Sixth principle of energetics

Material cycles have hierarchical patterns measured by the emergy/mass ratio that determines its zone and pulse frequency in the energy hierarchy. (Odum 2000, p. 246). M.T. Brown and V. Buranakarn write, "Generally, emergy per mass is a good indicator of recycle-ability, where materials with high emergy per mass are more recyclable" (2003, p. 1)." (http://en.wikipedia.org/wiki/Principles_of_energetics)