rdlFuelcells

The future is coming, gasoline and fossil fuels and their pollution will be a thing of the past. The replacement of this old technology is hydrogen fuel cells. They will soon be able to efficiently produce energy, with only pure water as a bi product. Fossil fuels desperately need to be replaced. Currently the USA imports 55% of its oil and it is expected to increase to 68% by 2025. When oil is burned for energy it gives off green house gasses and poisons the air and earth. This is a high cost financially and socially, because the oil comes from unstable places, where the money poured into those areas fund terrorism and atrocities. Oil prices will continue to rise as we use it up, there must be a replacement found, and it is fuel cells. The internal combustion engine is terribly inefficient. In a gasoline engine, only 18-20% of the energy in is returned as usable energy. Heat is lost through exhaust and cooling system, imperfect seals lose compression, an engine requires multiple pumps and auxiliary systems to run, and imperfect burns all lose energy. Battery powered cars are not much better. They lose energy starting with the battery @ 90% efficiency then with the inverter and motor dropping it to 72% over all, and as you trace the electricity to where it came from there are more drops, a plant is 40% efficient, then more energy is lost getting it to the charger where more is lost dropping it down to a total of 26% of the energy put in is usable. In a hydroelectric or wind turbine power plant, where it is nearly free energy, it can increase the efficiency up to 65%. There are many types of fuel cells: Polymer Exchange Membrane Fuel Cell (PEMFC), Direct Methanol Fuel Cell (DMFC), Phosphoric Acid Fuel Cell (PAFC), Molten-Carbonate Fuel Cell (MCFC), Solid Oxide Fuel Cell (SOFC), and Alkaline Fuel Cell (AFC). Each different fuel cell has potential for differing areas. The PEMFC is the most likely candidate to put into cars. It has a low operating temp, and can be cycled on and off like the engine of a car without excess wear. The low operating temp, 60-80 degree C, allows it to come up to temperature quickly and not have an excessive wait before it can be run. DMFC is a comparable source to PEMFC, but not as efficient and requires a platinum catalyst. PAFC could be effectively used for a small stationary plant, it runs at a higher temperature then PEMFC, and would take too long to heat up before running, and cannot be used for normal cars. MCFCs could be used for large stationary plants, they are high heat, 600+degrees C, and can cogenerate heat and power, because of the high heat they can run a steam plant. SOFC are the best choice for a large scale power plant, very high temperature, 700-1000 degrees C, and can also cogenerate heat and power. It is very stable in constant use, but cannot cycle on and off, because the high heat could cause part failure in a hot cold situation. AFC is an old design that requires pure Hydrogen and Oxygen, which makes it expensive and exacting. It has been used by NASA in space shuttles. PEMFC is the most likely candidate for use in vehicles. It works by an anode, like the negative terminal on a battery, conducting electrons freed for the hydrogen and channels dispersing the hydrogen over the catalyst. The cathode, like the positive terminal of a battery distributes the oxygen over the catalyst, and conducts the electrons back to the catalyst, and recombines them to the hydrogen and oxygen to make water. The electrolyte proton exchange membrane is in between the anode and cathode conducts only positively charged ions and blocks electrons. The catalyst is in between with the PEM, and is made up by platinum nanoparticles that are stuck to a porous surface to maximize surface are, and the platinum faces the PEM. On the anode side, pressurized hydrogen is forced thru the catalyst, which splits it into positive and negative ions,(2H 2 4H+ +4e- )and the electrons are conducted up the anode to a circuit to be used for productive energy. The electrons then return afterwards to the cathode, where oxygen is forced thru the catalyst and is split into 2 oxygen molecules which are negative,( O2+4H++4e-2H2O) and they combine with the electron and positive hydrogen molecules to form water.(overall 2H2+O22H2O) This process forms .7 volts, and therefore must be done by multiple fuel cells in a stack.