ECOLOGICAL MACRO ASPECTS OF ENERGY
PART II – Convenience VERSuS ENERGY efficiency
Girish Abhyankar
girish.abhyankar@gmail.
Phone: +91 9860547471
PREVIEW
We are the only one in animal kingdom using external energy (energy besides food generated energy) through medium of equipments – hardware and software – to derive following conveniences.
1) Security - shelters and storages,
2) Comfort - tools and machines,
3) Equipment aided enjoyment - toys and communication gadgetry.
Constructing, making tools, machines, and equipments is a process of decreasing entropy. A lot of low entropy energy is necessary in deriving the above mentioned conveniences for constructing/making, maintaining and running of structures and equipments.
Building shelter for security is beneficial only if low entropy embodied energy in stones and biomass is used and not beneficial when high entropy sand and mud is used because then, more energy is spent building shelters than the body energy consumed living without a shelter. Energy required in cooking food (10000 kJ per person per day) is more than the energy necessary digesting the uncooked food. (Total food intake itself is only 8000 kJ per day). Eating cooked food is beneficial only if heat by burning low entropy chemical energy in biomass is used and not beneficial when heat is generated by high entropy frictional energy or solar IR radiation.
Net convenience is possible only if the external energy resource is of low entropy.
Technology is the art and science of using external energy and its role is limited to changing the form of the problem, to one, better in respect of human capabilities of using external (low entropy) energy. Technology changes problem of “protection from the environment” to a problem of “building shelter”, a problem that can be addressed better than facing the environment. Similarly, the problem of “cooking food” is better than digesting the uncooked food. Converting a problem into another, better addressable problem, and also reducing effort (labour) due to external energy inputs, is the comfort.
Since accessing external energy and constructing/making, maintaining and running of structures and equipments requires energy, low input energy for the same benefit or higher efficiency is necessary for achieving convenience.
Net convenience is possible only if the external energy is put to use very efficiently.
Overall energy efficiency of direct and simple methods is better than that of complex methods because input energy in complex methods is high. Complex methods are adopted for perceived short term convenience - saving on labour at that time but net convenience is not achieved.
More convenience means lower efficiency resulting in lower net convenience defeating the very purpose of using external energy by technology.
Few examples from recent past:
| Direct and simple method - efficient | Indirect, Complex method - inefficient |
Considering energy inputs to… |
| Food gathering | Farming | Operations in farming |
| Self labour with appropriate tools | Animal labour † | Tame/breed; train and maintain animals |
| Grain grinding by stoned hand wheel | Wind mill operated grain grinder | Make, install and maintain the wind mill |
| Walking # | Bicycle* | Make and maintain bicycle and the path and carry weight of the bicycle
|
† Animal energy is for the animal’s own survival and reproduction and not for the master’s energy needs. Animal energy is, therefore, high entropy energy for the masters.
* Animals have no wheels. # walking on 4 legs requires less energy than walking on two.
Sources of external energy
Solar, wind and geothermal energy are high entropy sources. They can be used efficiently as free natural services only in the direction of increasing entropy: drying/germicide, separation of light and heavy particles, cooling by ventilation and local hot water usages.
Local biomass is a low entropy energy source when used as embodied energy making equipments. Low entropy coal and crude oil is used as heat source for thermal processing, warming and illumination. Few examples of harnessing wind and solar energy efficiently and conveniently using local biomass and thermal energy are: Sail boats driven by wind energy, water warmers by solar IR radiation, grain grinder or water lifting wheels by natural low entropy hydro energy such as high altitude waterfalls or tap able lakes.
CURRENT ENERGY USAGE TECHNOLOGY
Thermal energy released from coal and crude oil is converted to low entropy energies. On providing energy of activation fuel molecules burn and liberate heat. One part of this releasing thermal energy is used in lowering entropy of the other part - such as concentrating chemical energy (pyrolysis, cooking) or conversion into embodied energy (material processing - metal refining, heat treatment) or converted into work - mechanical energy (heat engines). Larger part of heat is thrown out in open in the form of exhaust - increase of entropy. Thus, only less than half of the released heat energy is transformed into embodied or mechanical energy.
Conversion to mechanical energy is geometrically represented below.
When heat is being released, gas molecules start travelling at high velocity in all directions. They act on total area of 4(pi)r2 inside a sphere of radius 'r'. To convert this kinetic energy of molecules into constrained mechanical energy, we can place maximum two pistons (all molecules forming a piston, moving in the same direction with the same velocity - constrained energy) of radius less than 'r' each, for the random gas molecules to act. Their area is less than 2(pi)r2. Molecular kinetic energy components in the directions, in which the two pistons can move, will only be useful for conversion into constrained mechanical energy. The ratio of “area available for random gas molecules to act" to “total area” is less than half. Thus only less than half of the thermal energy released can be converted into the constrained mechanical energy, more than half goes in exhaust, heat dissipation and entropy of the system increases.
Maximum achievable conversion efficiency
If Q1 is heat taken at temperature T1°K,
Q2 is unconverted heat thrown out as exhaust at temperature T2°K and
W is the work done, then
W = Q1 ─ Q2 (The law of conservation of energy)
W <>2 (The law of increasing entropy).
From the above expressions maximum achievable conversion efficiency W/Q1 is < style="position: relative; top: 12pt;">
Maximum achievable efficiency in terms of temperature (T1-T2)/T1 is also < style="position: relative; top: 12pt;">
And so, T2 is always < T1/2
Maximum achievable primary (thermal à constrained energy) conversion efficiency is always less than 50%.
Conversion efficiency in practice
The lower the temperature and the slower the speed of the process, the higher is the efficiency. But temperature depends on fuel input. Fuel input and speed depend on load, a varying parameter related to the usage. Efforts in improving efficiency necessitates controller for synchronous matching of parameters. Considering embodied energy inputs in controller overall efficiency may not improve. Efficiency reduces with aging, increasing energy for maintenance and deteriorating environment. Very little overall efficiency improvements have been possible on heat engines.
Overall efficiency
Mechanical energy is also further converted to electrical energy to be converted:
Back to mechanical energy (motors, compressors),
Back to thermal energy (heaters),
To chemical energy stored in batteries à electrical à mechanical (in electric vehicles) and to radiant energy (lighting, microwave oven à heat).
Electricity is only a transitory form of energy in all applications except in data processing and transmission.
Since energy is 1) lost at every conversion, storage, transportation, 2) consumed in making equipments 3) lost in maintaining the equipments, the overall efficiency of energy service is very poor.
Heating by electricity requires many times more coal than heating directly by coal. Motion by electric motor requires many times more fuel than motion by fuel run heat engine. Similarly, illumination by electricity takes a lot more fuel than illumination directly by the fuel.
Many human societies are marching towards greater and greater inefficiency.
SOCIAL EFFECTS
Overall efficiency of energy usage by technology is very low and therefore it gives rise to many new problems such as requirement of new skills (training and employment), exchange media (monetary systems and host of regulatory/monitoring systems), infrastructure, etc and also huge waste. Addressing new problems by technology again, increases energy usage, compounding the effect, generating more problems and more waste. Rate of waste generation then exceeds the natural disposal rate, accumulating the waste harmfully.
Energy efficiency and conveniences
Better convenience – security, comfort and equipment generated enjoyment - is the reason for opting energy inefficient methods. The convenience of using electricity is: button start, no noise and pollution at the place of usage, door delivery, available on demand, etc. Since coal and crude oil energy is readily available to many human societies energy intensive technologies are on the rampage for more and more conveniences – security and comfort. Even enjoyment by status is linked to use of energy, the more the energy use the higher is the status.
Overall energy consumption increases with inefficient and extravagant usage with effects:
1) High energy consumption systems – industrialisation - need reliably uninterrupted supply, in turn, control over resources, logistics and prices - matters raising conflicts. Every kind of pollution increases with energy usage. Both factors lower security, defeating the very purpose of using external energy.
2) Coal and crude oil reserves are available for free in nature but their processing, transportation, storage, etc and their usages by building equipments and maintaining them etc, including those for enjoyment, remain human functions - work load (work denotes “loss of freedom” and not “labour” in industrial world). Efforts to reduce human functions by automation technology actually increase the energy consumption and related effects - increased insecurity and increased work load. Thus, human society has to work to avail benefits of free energy. Work increases with energy consumption and increased work load lowers comfort (freedom), defeating the very purpose of using external energy.
3) Basis of enjoyment is peace and freedom, adversely affected by insecurity and increased work. Inevitably, largely energy dependent societies evolve “progress, success and status” as enjoyment (development is physical but progress, success and status is only psychological). Societies socially engineer following concepts of enjoyments, storage of enjoyments (by holding/saving money) through education, media and policies.
a) Competition, accessing power, hard work and “no time” (insecurity built-in).
b) Complex, fast, large, tall/high/deep, hi-tech, automatic, latest (inherently inefficient).
c) Artificiality-continuous growth, rising numbers, grand structures, clockwork discipline (heavily consuming energy, thereby reducing security and comfort).
d) Technology can solve problems by research and development, mass production, etc.
Nurturing such concepts result in rampant energy consumption, rapidly increasing, till the self limit is reached due to various reasons.
Perceptions
Perception of security, comfort and enjoyment varies with individuals and communities. Perception of local biomass generated and food generated energy usage (self labour) efficiency is obvious. But, when coal and crude oil energy is converted into high energy density fuels and electricity, overall energy efficiency and side effects thereof are not perceivable due to complexity of transformations and the time gap or the delayed effects.
Human sensory system is designed to responds to radiant, thermal and mechanical energy, required to face in nature, and hence effects thereof are perceived by us naturally. But since humans did not have to deal with electrical energy in the past effects thereof are not naturally perceived. (Perpetual motion machines involving mechanical, thermal or radiant energy are seldom but those involving electrical energy are very often).
It is not perceived that energy embodied (in equipments) also disperses, whether used or otherwise, and therefore, everything including all living matter come with an expiry date.
Perception of pollution by local thermal and mechanical energy usage (smoke and noise) is perceived but pollution by electrical energy usage is not perceived because power plants damaging ecology and polluting environment are located away from end user of energy service. Efforts are centred on improving energy efficiency of electrical equipments but such an effort is like attending a leaky tap of a broken water tank.
Efforts to clear/treat pollution (using energy) creates more pollution is not perceived. Individuals can not perceive that working more and working hard reduces their security, comfort and enjoyment in future.
Human society, neglecting/overriding the law of entropy, is in a trap of external energy.
Observation
Availability of free coal and crude oil energy should have reduced total work load of the human society, but the total work load and insecurity is increasing with the energy use.
Industrial technology has failed in providing net increase in security, comfort and enjoyment to the human society.
CONCLUSION
Conveniences - security, comfort and enjoyment - are derived only if the external energy usage is limited to the extent: no new greater inconveniences are created.
PART III – POST MODERN LIFE-STYLE (SUSTAINABLE ENJOYMENT)
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