Posted on: 07 September, 2007
Author: Rudolph Draaisma
Hydrogen does not occur in free form on Earth. The energy needed to free it from its chemical bonds can be used directly instead, making Hydrogen to be just an energy converter, possibly with environmental advantages, but definitely not an energy source. A water powered car is in conflict with the First Law of Thermodynamics. Though Hydrogen is the most abundant element on Earth's surface, it mainly is bond with Oxygen in water, one of the strongest chemical bonds known. This means that it takes quite a lot of energy to split water into Hydrogen and Oxygen, around 120 MJ per kg. The same amount of energy is released, when Oxygen and Hydrogen recombine to water (combustion). Why the same amount of energy, one may ask? The First Law of Thermodynamics says that if energy is applied to bring a system from one condition into another, the same amount of energy must be removed to bring it back into the original condition and this regardless how it is done. If there would be any difference in applied and removed energy, then we could create energy from nothing, by adding (input) less energy to bring a system into one condition, than what is removed (output) to bring it back into the original condition - a perpetual mobilae of the first degree. Thus let's consider an ideal hydrogen (water)engine, by which we poor water into it on one side and the same water (firstly as steam, but than condensing back to water at the original temperature), comes out on the other side. Then the first Law of Thermo says that there cannot be any mechanical energy developed on the shaft of that engine - it would have been created out of nothing! If there is an output of mechanical energy anyway, then this energy must have been added as an input as well. This is exactly what happened with the experimental cars, that were said to run on water only. No, they ran on the electrical battery in the system, that initially was charged from an external source. Claiming anything else, as the 'inventors' do, means to declare the First Law of Thermo to be invalid. None of the 'inventors' ever made such a declaration, has one? No, because they never considered the First Law and neither did "the Powers that Are", who believed the 'inventors' and therefore allegedly threatened, imprisoned, or even killed them - what a waste, if it is true. Many researchers, car manufacturers, inventors, etc, erroneously bring Hydrogen forward as an energy source. From the above we can however understand, that whatever energy Hydrogen would develop in any kind ofengine or device, originally came from other sources that were needed to produce and prepare that Hydrogen. Most likely these other sources were fossil fuels, so where is the environmental advantage? Moreover, as the total efficiency of the Hydrogen production process is far lower than 100%, these other sources delivered accordingly more energy, than what the Hydrogen can set free at combustion. Hence, Hydrogen is an energy converter and not an energy source. In terms of environment, the pollution with Hydrogen has moved from the engine to the production installations - it has not been eliminated, as erroneously is claimed by many. How about using solar energy to produce electricity with photo voltaic cells and using that electricity in an electrolysis process to split water into Hydrogen and Oxygen? Well, know that the typical efficiency of voltaic cells is around 25% and that of electrolysis 60% and thus the overall efficiency is 0.25 x 0.6 = 0.15 => 15% Then you just have Hydrogen and Oxygen gas, but especially the Hydrogen gas is very difficult to handle. Its volume is around ten times that of air at atmospheric pressure and it exudes through most metals. Compressing Hydrogen gas to smaller volumes takes a lot of energy (that must be cooled off as waste heat). To distribute it to the consumers takes energy also and in the end, the overall efficiency may even become negative, or hardly more than a few percent. This all has to do with entropy. If you don't know what that is, read my article: "What is Entropy", for an explanation. Know that the World presently burns fossil fuels to the equivalent of around 100 million barrels of crude oil per day (60% is coal -still being the World's main energy source). One barrel is 167 liter, ca 140 kg of mass and the energy content is roughly 40 MJ/kg, whereas the average solar intensity at sea level is in the size of a few hundred watts per square meter (around what the human body gives off in heat). Do you want to calculate on how big areas of photo voltaic cells would be needed to replace say only 1% of our present fossil fuel consumption? Even more, do you want to pay for it? There is much expectation from fuel cells, that run on Oxygen and Hydrogen, converting them to water and electricity without combustion. Also here we are talking about energy conversion, because where did the Oxygen and Hydrogen come from? A fuel cell is thus not an energy source. There are concepts for fuels cells that can run on natural gases instead, such as Methane. Because the output is water(steam) and not the original Methane, the First Law allows a net energy output and so it does. However, it shows that the total cycle efficiency is somewhat less than burning the Methane directly in a combustion engine. The fuel cell alternative definitely causes less pollution than the combustion alternative, but the economics remain in favor for direct combustion. How much more do you want to pay for your environmental friendly car? Source: Free Articles from ArticlesFactory.com Rudolph N. J. Draaisma is a double graduated engineer in electrics and mechanics, specialized in energy conversion, refrigeration, waste-heat recovery and alternative energy systems. Online expert advice against a moderate fee for short-term issues. Also providing: CAD drawings, Techn. Documentations, Calculations, Translations, R&D projects. Read more on the The Alternative Energy and Engineering Site