AN ENERGY ANALYSIS OF THE DAN TAYLOR FAMILY'S OZARK FARM

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The double lines on the diagram represent the boundaries of the system (the farm). The symbols represent various things (the sun, land, plants, animals, people, equipment, etc.) both inside and outside the system (on and off the farm). The solid lines which connect these symbols indicate energy flows and the dotted line represents the flow of money.

As we can quickly see, energy flows into the Taylor system from two main sources (the sun and the land, both represented by circles) and from exchanges made with the main economy. We also see that energy flows out of the system in the form of goods produced (in this case, animals ... cattle and hogs) and in the form of degraded energy (depreciation and waste heat). The heat sink symbol on the lower right represents the total of all depreciation on equipment, tools, and buildings combined with the waste heat generated by the respiration of the system's plants, animals, and people plus the friction and other inefficiencies inherent in any energy transformation process.

Obviously, the total amount of energy flowing into the system must equal the amount flowing out. This is the first law of energetics (thermodynamics), which states that energy can neither be created nor destroyed.

The degraded energy shown on the diagram (the energy which flows down into the sink at the drawing's lower right) just as surely represents the second law of thermodynamics. Which states that in any energy-transforming (work-performing) process, potential energy is degraded into a form that is no longer able to do work. This is also known as the law of increasing entropy (where "entropy" is a scientific word for disorder).

Our system contains several energy modules within its boundaries. A bulletshaped module represents a producer ... such as a plant or-in a larger sense-the raw Taylor farm itself. A hexagon-shaped module indicates a consumer ... such as an animal or a person (in larger studies, a major consumer is often a city). Each of these modules is attached to the heat sink: this represents the metabolism of the organism.

The water tank-shaped (round on the bottom, pointed on top) modules indicate a storage of some material ... such as biomass, buildings, or money. They, too, connect to the heat sink . . . which represents their depreciation with time.

The pointed box modules represent interactions between two other modules. Their connections to the heat sink show that the energy of two interacting flows cannot produce work at 100% efficiency (which would defy the second law of thermodynamics).

The rectangular box symbolizes a sub-unit ... in this case the farm structures, equipment, and the work done by the Taylors with such tools. The diamond-shaped modules between the Taylor farm and the main economy represent the exchange of money for goods and services (other forms of energy). Notice, when such exchanges are made, that money quite obviously flows in the opposite direction of energy.

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