Wednesday, June 13, 2007

Reviewing Thermodynamics


Yet another conversation with a friend committed to sustainability, jogged, or should I say hammered home a fundamental element of sustainable business; thermodynamics (or thermo to those fortunate enough to have gone to engineering school). It's all about energy, and there is a finite amount contained within the boundaries of the planet Earth. All we've got to do is harness the incoming solar radiation and we'll be all set.

Laws of Thermodynamics

Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy.

First Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another; it cannot be created or destroyed.

The Second Law of Thermodynamics states that "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state." This is also commonly referred to as entropy. A spring-driven watch will run until the potential energy in the spring is converted, and not again until energy is reapplied to the spring to rewind it. A car that has run out of gas will not run again until you refill the tank.

Entropy is a measure of disorder.

These laws govern every industrial process in one shape or form. The thermodynamic analysis of ethanol production using corn yields a result that makes one wonder why we're doing it if it's supposed to be for "green" reasons. My mistake; it's government yielding to political pressure from constituents in the corn belt.

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