A real fuel cell is merely a few pieces of thin plastic sandwiched around two carbon plates that have inlets for fuel and air. Like all chemical reactions, reverse electrolysis has a byproduct, water. This is revolutionary because not only does this process create energy, but it does not pollute the environment since the only byproduct is water that is suitable for drinking.
.
Types of fuel cells.
There are seven major types of fuels cells; the main differences between them are fuel types, efficiencies, and operating temperatures. Of course, there are other differences but the main theory of how each type produces energy remains the same. Each type of fuel cell is suited for a different type of energy production, with different benefits, and different problems. Figure 3 shows the operating characteristics of several common fuel cells.
Popular Fuel Cells.
Alkaline Fuel Cells .
Alkaline Fuel Cells have long been used in space shuttles by NASA. For example, an Alkaline Fuel Cell was used on the Apollo aircraft for powering small devices and creating drinking water. This device operates at about 150-200 degrees Celsius with an efficiency of about 70 percent. The fuel cell is run by soaking liquid alkaline potassium hydroxide into a matrix-like electrolyte. This is very beneficial because the process of creating energy is much faster meaning better performance from the fuel cell. The energy output from this fuel cell is about 300W-5kW. Until very recently, alkaline fuel cells were too expensive to use in every day devices. Many companies have banded together to try and draw down the price.
Direct Methanol Fuel Cells .
Direct Methanol Fuel Cells (DMFC), like the proton exchange membrane fuel cells, use a polymer membrane as the electrolyte. The main difference is that in the DMFC, the catalyst in the anode is able to extract the hydrogen directly from liquid methanol fuel. This eliminates the fuel reformer that would be needed to extract hydrogen from methanol.
