Pressure to generate energy?

[JavaProphet]

So, I was sipping my mountain dew, and I discovered something fun. The pressure of my sucking was causing it to rotate in the cup. I figure it was having more come towards to low pressure than there was available to enter my mouth.

Could this rotation be harnessed, say in space, to generate energy from the vacuum? My concern is that space has no energy, so where is it coming from? Space sucks.

I figure the energy is coming from the pressure of the water, which would be stored in the water on earth.

Water battery?

It could be done with any fluid, theoretically.

Will it work for power generation?

[maltesh]

It's the ambient air pressure that's pushing the liquid up into your mouth, and earth's atmospheric pressure won't allow you to suck a column of water higher than about ten meters, as that's where the pressure of the extra water in the straw matches the atmospheric pressure. So (assuming that's what you're talking about) you can't run an evacuated pipe from the ocean to space and run a turbine off it.

[Bill Phil]

Don't nozzles turn the pressure of the working fluid into kinetic energy? Like on rocket engines? Or is this unrelated?

[JavaProphet]

@maltesh I'm talking about using this purely in space. No earth. Perhaps on earth, but it would need some pressure difference.

A pressure battery.

You use a pressure difference from anything to make a fluid spin, from there, stick a generator on the spinning fluid, and wallah. You lose fluid to the vacuum, but in space, this wouldn't reduce efficiency. In say, a battery, it would slowly fill with the fluid, and equalize in pressure, losing efficiency.

[vger]

Sounds like it's basically the most inefficient steam engine ever.

If I understand correctly, you're talking about intentionally dumping water into space. Spinning a turbine as the water rushes from a pressurized compartment into a vacuum?

You're also going to generate thrust as a biproduct, which is another thing you just shouldn't have to deal with if all you're concerned with is making electricity.

Or if you're talking about pumping water into space from Earth, you're actually talking about something that would be even harder to accomplish than a space elevator.

You'd be much better off trying to "beam" energy to your space vehicle. You'll get better results, without having to build the strongest pipe in the world, or the most powerful pump.

Edited June 18, 2015 by vger

[maltesh]

@maltesh I'm talking about using this purely in space. No earth. Perhaps on earth, but it would need some pressure difference.

A pressure battery.

You use a pressure difference from anything to make a fluid spin, from there, stick a generator on the spinning fluid, and wallah. You lose fluid to the vacuum, but in space, this wouldn't reduce efficiency. In say, a battery, it would slowly fill with the fluid, and equalize in pressure, losing efficiency.

In space, there is no free atmosphere hanging around to create your pressure differential for you.

So, by necessity, whatever you use to push the water out of its container into space is going to expend more energy doing so than you can recover by pushing the water through a turbine. And as such, there are more efficient ways to directly use that energy that don't lose you water (or whatever fluid you decided to use).

[Nibb31]

You can get energy out of a pressure differential. However, you need more energy to create that pressure differential in the first place. The efficiency of the system will be very poor.

[YNM]

You're basically talking about rocket engines. The release of pressure (bet that whatever fuel/fluid you carry is going to be pressurized, compared to the vacuum of space) is converted directly to additional kinetic energy for you. Or add some alternators, but you'd need to carefully engineer it to steer you correctly...

[shynung]

Rather than pressurized water, it's much better to use pressurized hydrogen peroxide, and stick a silver mesh filter just after the input valve, but before the turbine inlet. This will generate a stream of superheated steam and hot oxygen gas at much higher pressures than a water tank of comparable pressure and mass. This system works almost anywhere, in almost any condition, within the temperature ranges where hydrogen peroxide is a liquid.

[pincushionman]

The problem with pure expansion pressure-driven power generation devices is the energy density sucks compared to those that rely on chemical reactions.

[Nibb31]

The problem with pure expansion pressure-driven power generation devices is the energy density sucks compared to those that rely on chemical reactions.

I see what you did there !