Bloc en català

dissabte, 22 setembre de 2012

Human heat

We are in an interior room where natural light doesn’t come in. Generalization of electricity has meant that we solve this problem just by pressing a switch usually placed near the entrance that ignites an artificial source of light (i.e. a strip light). This source illuminates walls and objects contained in the room, and the same in all directions make this reflection, a fraction of reflected light reaching our eyes just allowing us to create an image of what surrounds us. But if we press the switch other time instantly becomes dark. The second action is natural because we daily experience proves this, but someone has stopped to think where the light go.
It may seem a trivial question because if we turned off the light that is over, but it is not. Energy isn’t created nor destroyed, the room that we were hasn’t opening up so all the energy that enters the electrical wires trapped inside the room, yet we see the light disappears. Really this is absorbed by the walls, and it joins energy as heat. If walls were perfect reflectors with less than a second by activating the switch, would suffice to keep the room lit up. In fact, the 60 W that laptop consumes which I’m preparing this written, are expelling as heat by a little fan, and this also applies to any device, nobody and nothing consume energy, we use it and we throw it in form of heat (remember us heat is also a form of energy).
When we talk about global warming we tend to think that the main problem is CO2 in the atmosphere. But it turns out that the coal from which the CO2 has also released energy. As the example of lighting energy that we believe it is consumed and nothing more, however the only energy that we use its transformation and we throw when we are no longer useful. For example we have a car that uses the energy stored in the fuel, it uses about 30% of fuel energy to move and the rest thrown away as heat; while the car is moving, it’s  suffering a resistance that makes it lose energy (we must continue pressing the accelerator while traveling); the energy that lost the car, does it as heat, and 70% of the energy supplied to keep moving the engine is losing as heat too; when the car arrives a place it stops and it leaves all energy that it has throwing the heat. The end result is that all the energy extracted from the fuel used to move is transformed into heat. This happens in any activity, the fate of the energy used to heat became incorporated into the already existing in the atmosphere.
In the pre-industrial age human activity was based on animal power. Coal is burned only for heating or the steel and metallurgy made by blacksmiths, plumbers and goldsmiths. The power that was available was very small and consequently the heat released was very small, but the invention of heat engines changed all. Currently powers used are thousands times higher than pre-industrial age powers. Today we must add the use of fossil energy that were not used in the pre-industrial age: coal and nuclear.
Coal and hydrocarbons were biomass that died coated energy in their graves, and now we release the energy at a rate much higher than was captured and every year we release into the atmosphere as much energy as captured in the millennia. On the other hand releasing nuclear energy was languidly over time and is partly responsible for geothermal energy, but our nuclear plants force them to release that energy as you would in a few million years. Summarizing human activity is maintained by the massive use of fossil fuels is launching spectacular amounts of heat in atmosphere that was at the same time increasing the greenhouse effect, helped by the CO2 liberation inherent in burning of fossil fuels.
Each year we have hot summers, while every summer we beat records of energy production, which just in holiday time when consumption download. Global warming has too many issues and most importantly, the greenhouse effect, but we think the current energy consumption usually forgets in the speech. Thus instead of thinking about how we don’t expend energy stupidly in example to illuminate roads at night (see satellite image nocturnal) continue to increase the use of energy, and look for other sources to replace coal as massive increase nuclear (paper on guardian advocate replacement). There are too many interests behind the energy companies and enough complicity on the part of the user accustomed to air conditioning, television and the easy life. It is easier to blame CO2 and talk about electric cars which nobody has yet said which kind of energy think them to produce electricity which makes them move,  of course it wil come from fossil energy sources.

Today humans have become us a little sun inside the planet, we add to the heat from the star of our head from daily activity. Unfortunately sustained growth that requires of our economy requires increasing day by day the amount of energy used. With current consumption and the expected increase, it is impossible that renewable energy can cover it. Harnessing the energy release as nuclear or fossil fuels is adding heat to warming produced by feedback and greenhouse. So replace fossil fuels with nuclear or other inventions to collect solar energy in space will not solve anything. We need to reduce our energy consumption even if it means radically changing the economic system that the current crisis has also proven to be quite a mess.

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