ELI5, why can’t we convert sound to electrical energy for use? I know microphones convert sound to electrical signals but why is producing energy from waste sound not viable?

500 views

[ad_1]

ELI5, why can’t we convert sound to electrical energy for use? I know microphones convert sound to electrical signals but why is producing energy from waste sound not viable?

In: Physics
[ad_2]

It’s possible but you’d have to harness an incredible amount of sound to make it worth the effort.

Microphones do that on a small scale, the problem is that sound energy is so much weaker than general wind energy that sound energy isn’t really a viable power source.

Quantity and efficiency.

Wind and Solar could be done EN MASS. Renewable resource isn’t exactly renewable, YES the source of power is there, but what about the equipment needed to generate enough power to justify it?

And generally, the weaker the force, the smaller the device needs to be to be actually moved to generate electricity signal. And thus more device is needed, if you want less device, then you need a stronger source of power.

One way to generate is via water, fill a tub with water, use sound to make waves then use the motion to create energy, now look at how much noise you need, its just not feasible.

Microphones don’t generate electricity by the sound, but are fed electricity which powers the magnet allowing the sound to be transferred as a different electric signal when sound is introduced.

It would take a lot of sound to generate electricity. You could have coils and magnets set right to allow the vibrations to move everything just right. This would be not a lot different than turbine or piezoelectric might be.

Sound that produces a useful quantity of power is stupid loud

At 120 dB, if you capture all the energy from sounds passing through 1 square meter then you’ll get 1 watt of power. Just a single watt.

You want to run a 1200 watt microwave off sound captured in a reasonable area? Well 12 m^2 of 140 dB sound will do the trick but it’ll be quite uncomfortable. 150 dB would let you do it with just 1.2 m^2 but that’s the sound of a jet engine a few meters away so you’ll go deaf pretty quickly and would be better off just using the jet as a generator

There just isn’t enough energy in sounds

To give you a sense of scale.
The speakers at a heavy metal concert in a stadium need 15,000 Watts of power.
If we somehow collected all that energy, you would be able to cover the average power consumption of an electric car on EPA’s Highway test schedule: 14,000 W.
So there isn’t a whole lot of power.

There aren’t a whole lot of natural phenomenon that are louder than a concert by Slayer over a long period. And none where it wouldn’t be easier to just tap the source of the sound directly, rather than collecting the energy from the sound.

Also the power is spread out over a wide area, so we are unlikely to get all of it.

That’s sorta what wind turbines do. However, it’s not as electrically efficient to take high frequency sound waves as an air movement energy source as it is to take constant speed wind as an energy source. It’s not viable because there are larger amounts of air movement energy available from other sources.