Tag Info

Hot answers tagged

33

For the photons that make up light to exist they have to be travelling at the speed of light. This means that to store them you have to put them in a container where they can move around at the speed of light until you want to let them out. You could build the container out of mirrors, but no mirror we can build is 100% reflective, or indeed can be 100% ...


23

Your examples are a bit misleading. For example you say: We can store cold (ice),heat (i.e. hot water bag) But we can only store heat temporarily, just as we can only store light temporarily. Your ice pack will eventually heat up and your hot water bottle will eventually cool down, just as light stored between two mirrors will eventually escape. ...


5

Storing electricity as electricity is currently possible only in capacitors. A lot of fuss is made about the potential of super-capacitors and ultra-capacitors to scale up, but little has happened yet at the grid level. Almost everything else involves converting electricity to a different kind of energy; and then converting it back to electricity when ...


5

One alkaline AA cell has about 11 kJ of energy. For a laptop battery, it is 360 kJ. Chevrolet Equinox Fuel Cell has 58 MJ of energy. One kilogram of TNT carries about 4.184 MJ of energy. Divide the numbers from the previous paragraph by this constant to see that the AA cell, laptop battery, and electric car battery have 2.6 grams, 86 grams, or 14 kilograms ...


5

(I tried to post this response with chart and links, but I'm new here, so the system won't let me include images or more than two links. Please cut and paste the other links to view them in your browser.) This diagram from the NH3 Fuel Association (taken from www.nh3fuelassociation.org/about-us--why-nh3) (scroll down the page) may answer part of your ...


5

Making ammonia is an absolute bugger because nitrogen is so unreactive. The normal route is the Haber process, http://en.wikipedia.org/wiki/Haber-Bosch, but this requires high pressures and temperatures. Hydrogen is easy to produce from electricity, and I guess that's why it's the first choice for storage of energy generated by unreliable sources like wind ...


3

I'll try to answer your question in the spirit of how you asked it. Basically you can't really store anything you've mentioned. The ice will eventually heat up, the heat will cool down and the battery will lose charge. A box of mirrors with light shined in it will "store" light like your other examples but it will lose the energy much faster then any of ...


3

This site covers four current modes of electricity storage: 1.Pumping water from low to high elevations for future hydroelectric use as needed. 2.Melting salt at solar farms to several hundred degrees and storage in insulated tanks, for future use. 3.Compressed air energy storage by wind farms into underground geologic formations. 4.Utilizing "flow ...


3

The problem with maintaining a constant voltage is not restricted to flywheels, but is important for all kinds of generators. Power plants have to generate a constant voltage independent of the momentary load on the grid, yet this is not how a plain electric generator works - it will spin slower under load, just as your cordless screwdriver does when you use ...


3

There is actually a technology called "energy recovery linac" that is designed to take the power stored in a beam and deposit it back into the fields of the accelerating cavity (always superconducting in this case, it seems) so that the next beam can take it. Sort of a relay race -- when one beam gets exhausted after too many collisions, another, higher ...


1

The equilibrium position of the molecule from the surface will be due to the tradeoff between a (relatively) long range Van der Waals force (or electrostatic force if the molecule is charged or dipolar) and the short range exchange repulsion. You would expect the minimum to be when the molecule touches the surface, so it would around the Van der Waals ...


1

As Everett says in his comment, you can't apply a huge voltage, or indeed any voltage, across a superconductor. Because the resistance is zero the potential difference between any two points in the superconductor is also zero. If you have a superconducting loop/coil, when you put energy into it you are basically storing the energy in the magnetic field ...


1

It's hard to store light as light because the most common way light interacts with matter is through absorption and emission, which is how mirrors work. However light rays can be bent by gravity, so it would be possible to arrange several massive stars in a way such that a light ray would move in a loop around the stars without energy loss.


1

A battery's energy capacity is normally quoted in Amp-hour, (or mAh) the number of amps it could (in theory supply) for an hour. If you multiply this by the voltage you get energy. Specifically if you multiply by 3600 seconds in an hour you get Joules. A NiHH rechargable AA cell is about 2200mAh and is 1.2V; 2200mA * 3600s * 1.2V = 9.5KJ, an alkaline (ie ...



Only top voted, non community-wiki answers of a minimum length are eligible