Energy Conversion Any work on direct to electric?

[sdifox]

Is there any work being done on converting to electrical energy without involving whipping coils inside magnets? As in higher efficiency energy conversion.

 

[PowerEngineer]

The answer to your question is "yes"; there are several methods that can (and are) used to produce electricity without a traditional electromechanical generator (i.e. whipping coils inside magnets). These methods include solar cells, fuel cells, thermocouples, and others you can google (with grains of salt).

The electromechanical generator is actually a very efficient piece of equipment, converting roughly 99% of the rotating mechanical energy of the shaft into electrical energy. It's the the processes for turning fossil fuel into rotating mechanical energy (burning for heat to produce steam released into a turbine to turn the shaft) that is pretty inefficient -- only 30%-50% -- that deservedly gets the most attention.

 

[silverpig]

PowerEngineer pretty much has it.

Solar cells use the photoelectric effect, fuel cells basically just burn hydrogen in a special way, and thermocouples basically use the peltier effect, but are extremely inefficient (best numbers I've seen are about 4.5%).

 

[sdifox]

I guess I should be more specific, right now fuel cell looks promising, but there is still the production of hydrogen which is not exactly energy efficient. I am thinking something along the line of chemical reaction single stage to electricity. I am not even sure it is possible.

 

[CycloWizard]

Originally posted by: sdifox
I guess I should be more specific, right now fuel cell looks promising, but there is still the production of hydrogen which is not exactly energy efficient. I am thinking something along the line of chemical reaction single stage to electricity. I am not even sure it is possible.

Combustion (fossil fuels --> electricity) is a reaction. Any exothermic reaction, one that releases energy when the reaction moves forward, can be used to generate electricity.

The reason hydrogen is used in fuel cells is because its oxidation (H2+2O2-->2H20) has a very high exothermicity. This allows lots of energy to be stored for little weight, since oxygen is readily available and a mole of hydrogen only weighs 2 grams. You can fit a lot of moles of hydrogen into a very small container by pressurizing it, then simply react it with oxygen from the air and you're done. The everlasting problem, however, is how to get the hydrogen in a highly pure form, since the catalysts used in this reaction are easily poisoned.

Alternatively, many groups are looking at ethanol or methanol fuel cells. These fuels are easier to produce but more difficult to extract energy from. The energy released per mole of reactant is nearly as high as for hydrogen, so the benefits of the alcohol fuel cell are similar to that of the hydrogen fuel cell. These fuel cells need more pieces (typically reformers) to generate the 'fuel' species actually used by the catalyst to produce electricity. This is where the tricky part comes in and the research is focused.

 

[Matthias99]

Originally posted by: sdifox
I am thinking something along the line of chemical reaction single stage to electricity. I am not even sure it is possible.

A chemical reaction that produces a net electrical charge? There are plenty; that would be what is commonly referred to as a 'battery'. You probably have one in your CD player or iPod right now.

However, they're generally not naturally occurring, and most such reactions produce relatively low voltages (for instance, alkaline batteries are only 1.5V, and Li-Ion cells are only ~3V), and the power is naturally DC. These are both bad properties for large-scale power distribution.

 

[Mday]

dont forget the piezoelectric effect... pounding a crystal generating electricity

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but matthias pretty much has it all. most chemical reactions used to produce electricity are batteries. fuel cell would be the other compact type.

look up the various types of batteries (chemical reactions) that are in use. It's not just what you can find at radioshack.

 

[sdifox]

Originally posted by: Matthias99
A chemical reaction that produces a net electrical charge? There are plenty; that would be what is commonly referred to as a 'battery'. You probably have one in your CD player or iPod right now.

However, they're generally not naturally occurring, and most such reactions produce relatively low voltages (for instance, alkaline batteries are only 1.5V, and Li-Ion cells are only ~3V), and the power is naturally DC. These are both bad properties for large-scale power distribution.

Yeah, a voltaic pile would fall within my description, but not very practical for large scale. I am thinking scaled generation of course.