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Entropy production delusion

It is common in knowledgeable circles to talk about the development of civilization in terms of entropy discussion. The term 'entropy...

Monday, July 15, 2013

The energy and material duality that invariably determines what happens

It is interesting that text book items are quoted without attempting to provide a sound contrary argument to the assertion that the systems of civilization are irreversibly using up limited natural material capital and producing material wastes. This assertion does not appear in text books because it is an innovative way of looking at the fundamental principles of what invariably happens. Leaving aside the controversial radiation (a process in which energetic particles or energetic waves travel through a vacuum) of the solar energy from the Sun, some of this incident solar energy is transformed to heat energy in air in the atmosphere. The consequences are winds (kinetic energy of air) and numerous other operations that are taken for granted. Some of the incident solar energy is used to produce chemical energy (carbohydrates) in plants (made of materials that grow and then decay). Some of this solar energy is absorbed in the oceans so affect the currents that have such an impact on other operations. Some of this solar energy is now absorbed in solar panels where it is converted to electrical energy.

A discussion of what happens in operations (processes) should also consider what happens over time to the system (made of materials) in which the process takes place. The nature of the process depends on the state of the system. If the system does not exist then the process cannot occur. There is a vast amount of heat energy in the oceans and this has an influence on many natural operations, such as currents. But only a very few technological systems have been installed to convert a very small proportion of that heat energy to electrical energy. All existing systems age due to the action of natural forces, including friction. So the nature of the processes carried out in an aging system adapts to the changing environment of the operation. The power of a petrol engine declines over time as many of its components wear.

The mathematical equation for energy = force x distance is often quoted as underpinning the process. Energy is transformed when it flows to do work. That is reality is embodied in the mathematical definition of work. Stored energy, such as the bond energy of chemical compounds, do not do work. So processes always involve the "flow of energy" and any discussion that just uses the short hand term "energy" presumes, unwisely, that the qualification is understood. That work statement is a well-recognized fundamental principle but it relates to only those circumstances where the energy associated with the material has the potential to do work by flowing, either spontaneously or when activated. That energy equation above has no relevance in energy transformation but other (thermodynamic or fluid dynamic) equations underpin these transformation processes. But all processes involve the irreversible flow of energy through a system made of materials. Some mathematical equations deal with aspects of the nature of the operation (process) but often they have to have allowance for real effects such as friction.

Some processes that have a stage which entails the transformation of energy to do work do not have an associated transformation of material. A generator does work in transforming mechanical (kinetic) energy into electrical energy with a high efficiency as only a small amount of that kinetic energy is dissipated as heat energy due to friction. The material lost in the bearings due to this wear is a long term problem for the maintenance people and those who have to pay for this dose of reality. But the generator is not transforming material in the process. Heat energy does the work to provide kinetic energy in gas turbines without a material transformation. Pressure energy does the work to provide kinetic energy in water turbines without a material transformation. The filament in a light bulb transforms electrical energy into visible light energy (and some heat energy) without transformation of the filament material although the filament will slowly degrade. 

On the other hand, as is now well known, the coal combustion work process transforms chemical energy in the coal to heat energy and transforms the material (mainly carbon) into gaseous, vapor and particulate wastes. The process of transforming (refining process) iron ore to metallic iron through the work done by the flow of the energy input produces vast amounts of waste heat. Both energy and materials are transformed in both of these processes. All natural processes also have the dual (energy and material) transformation process. The functioning (metabolism) of the human body is a classic example.

So it is only in some technological systems that the flow of energy to do work entails only the transformation of the energy. Most of the processes in these systems entail the transformation of both energy and materials. Ironically this significant difference between the operation of processes in technology systems is not covered in engineering courses at universities. Thermodynamics and fluid dynamics cover the irreversible flow of energy (increasing entropy - Second Law of Thermodynamics) in doing work in the operation of technological systems. Chemistry covers the transformation of chemical compounds (material) due to the flow of energy in (endothermic) or out (exothermic) of the reactions. Physics embraces the impact of numerous natural laws including the conservation of mass (of materials) on the operation of physical systems without taking into account that mass is transformed into waste in the aging process and often in the work process. Other subjects cover what happens (such and stresses and strains) to materials in operations.

The fundamental operational principles enunciated here are governing what is happening in current operations even though most people do not understand the nature of this irreversible process. The technological infrastructure hosting this unsustainable process is already degrading the life support system. Future widespread improved understanding of these fundamental principles can only lead to smarter decisions about how to power down.

Denis Frith

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