Boiling Water In Space

[All Seeing Eye]

How close would water need to be to the Sun in space for it to boil??

In order to generate electricity we heat up water and use the steam to turn turbines so I was thinking that if you built a powerplant in space and had it a certain distance from the sun the water would boil from the heat and the steam could be used to turn turbines, turbines that would move much more quickly because of the lack of earth gravity.

So the Sun boils the water, the water steam turns turbines and then the steam is passed down pipework AWAY from the sun where it cools back down into water. That water is then pumped back towards the sun where it once again boils.

The internal systems such as any pumps for pumping the water and steam could be powered by external solar panels.

The electricity generated from the turbines is converted into a focused beam of Microwaves which is fired towards Earth and collected by an orbital collector and beamed down to Earth.

The size of the space based powerplant IMO is the bigger the better. The boiling water turning turbines method will create more energy than simply having solar panels. You could have just one large powerplant or several small ones.

I would think it would need to be pretty large in order to get a powerful enough microwave beam to reach Earth. To ensure a full beam reaches Earth there could be several 'collector relays' along the way which convert the mircowaves to power and create a new focused microwave beam. power will be lost en-route but power should still reach earth.

Another use for such a powerplant would be a space based colony (something like jupiter Station on Star Trek capable of holding a large number of people).
Perhaps a space based colony orbiting Venus, it would be closer to the powerplant and would gain more power from it.
Would an orbital space colony be capable of orbiting Mercury?? I'm not sure if it would be too hot for humans that close to the Sun?

Perhaps one day there would be a massive array of these powerplants all connected in some kind of net around the Sun channelling all the power into a single microwave beam.

Maybe one day we will have batteries that can store enormous amounts of power. The powerplants all work together to charge a large battery which is transferred to Earth orbital periodically where it beams the power down. As one battery leaves for Earth another fresh battery arrives for charging.

 

[Jadzia]

How close would water need to be to the Sun in space for it to boil??

Depends very much on the water pressure.

In order to generate electricity we heat up water and use the steam to turn turbines so I was thinking that if you built a powerplant in space and had it a certain distance from the sun the water would boil from the heat and the steam could be used to turn turbines, turbines that would move much more quickly because of the lack of earth gravity.

So it's basically a solar power driven turbine. We can make these on Earth you know, which would be a lot easier than space based, and since they are carbon neutral they don't contribute to global warming, they're green. There would be land area limitations, but less than what would be taken up by (relatively inefficient) solar cells.

But you want to discuss space based so I'll contribute this... You could use a thin reflecting film to shield sunlight away from a "cooling area". Water doesn't need to be pumped millions of miles out. But as we've talked about before, space doesn't cool things that well. Your cooling zone would need a large surface area to radiate heat away from the water quickly enough.

 

[All Seeing Eye]

So it's basically a solar power driven turbine. We can make these on Earth you know,

That's simplifying it a bit. The amount of power that could be generated so close to the sun is enormous compared to it being Earth based and size isn't a problem in space. In space you only need to get the water close enough to the Sun, on Earth it's far less efficient.

But you want to discuss space based so I'll contribute this... You could use a thin reflecting film to shield sunlight away from a "cooling area". Water doesn't need to be pumped millions of miles out. But as we've talked about before, space doesn't cool things that well. Your cooling zone would need a large surface area to radiate heat away from the water quickly enough.

Perhaps a large thin rectangular area where the water is more spaced out, It could still be pumped away after cooling.

 

[Jadzia]

In space you only need to get the water close enough to the Sun, on Earth it's far less efficient.

That thermodynamics is at least true. The bigger the temperature difference between hot and cold sides of the heat engine, the more efficient the heat engine is. Which is why internal combustion engines work more efficiently in cold weather.

 

[Scout101]

you can generate more power closer to the sun, most likely, but you'll also LOSE a lot more having to transmit that power. Unless you have an idea for a lossless RF power transmission system?

you've also got to consider other things floating around the system here. Can't just line this up with Earth, as the Earth is moving really fast. Can try to get this turbine going just as fast, on the same trajectory, but you've got to factor in the Moon, as well as likely Venus and maybe Mercury, depending on how close you get. And as you want liquid water in space, you'd have to be decently close...

 

[Squiggy]

How close would water need to be to the Sun in space for it to boil??

Water boils off in a vacuum. So...anywhere will do.

 

[All Seeing Eye]

 

[Squiggy]

No. The "cooled water" would be ice and wouldn't flow back to the boiling area.

 

[All Seeing Eye]

No. The "cooled water" would be ice and wouldn't flow back to the boiling area.

It would not cool down instantly to ice, it's near the Sun and close enough to boil. Before it cools down too much in the sheltered area it would be pumped back around to the front. The cooling area is only to turn it back into water from steam.

 

[Squiggy]

No. The "cooled water" would be ice and wouldn't flow back to the boiling area.

It would not cool down instantly to ice, it's near the Sun and close enough to boil. Before it cools down too much in the sheltered area it would be pumped back around to the front. The cooling area is only to turn it back into water from steam.

No. If it's not facing the sun, it won't boil. Space is cold.

 

[All Seeing Eye]

No. The "cooled water" would be ice and wouldn't flow back to the boiling area.

It would not cool down instantly to ice, it's near the Sun and close enough to boil. Before it cools down too much in the sheltered area it would be pumped back around to the front. The cooling area is only to turn it back into water from steam.

No. If it's not facing the sun, it won't boil. Space is cold.

eh.

The area where the water boils will be facing the Sun. The area where the water will cool back down from steam to water will be facing away from it.

 

[Squiggy]

I know, and it will turn to ice, not water.

 

[All Seeing Eye]

I know, and it will turn to ice, not water.

It's a continually circulating machine. By the time the steam ends up in the cooling area it will already be getting pumped back around.
Boiling hot water boiled by the Sun won't instantly cool to ice on the way back around.

What stops Human blood from turning to Ice when people are in space?

 

[Jadzia]

That looks fine to me. And to address Squiggy's concerns -- you could easily control the rate of cooling if there is risk of any freezing. But once up and running we'd expect the generator to operate at fairly constant hotside-coldside temperatures.

To add my own thoughts to the design: If the heating area is a plate facing the sun, the cooling area could be a plate at right angles to that, which would radiate sidewards. (I'm not sure if that's what your diagram is already showing.)

 

[All Seeing Eye]

Hmmmmmmm. I mentioned in the OP about a space based colony having the energy beamed to them, I never considered having the powerplant actually attached to the space colony itself! The living area will be sheltered from the Sun of course.

 

[TheMasterOfOrion]

Have your astronaut take a bottle outside the space station. Have him/her open up a bottle of water in zero G, zero pressure.
Q:
does it freeze?


No water would take a long time to radiate its heat away so it...

A:
evaporates

Instantly boils

 

[All Seeing Eye]

Have your astronaut take a bottle outside the space station. Have him/her open up a bottle of water in zero G, zero pressure.
Q:
does it freeze?


No water would take a long time to radiate its heat away so it...

A:
evaporates

Instantly boils

But the water in the powerplant isn't outside in the Vacuum of space. It's in a machine in an enclosed environment.

 

[Squiggy]

Hmmmmmmm. I mentioned in the OP about a space based colony having the energy beamed to them, I never considered having the powerplant actually attached to the space colony itself! The living area will be sheltered from the Sun of course.

You mean...like a solar panel?

 

[All Seeing Eye]

Hmmmmmmm. I mentioned in the OP about a space based colony having the energy beamed to them, I never considered having the powerplant actually attached to the space colony itself! The living area will be sheltered from the Sun of course.

You mean...like a solar panel?

Solar panels wont make nowhere near as much power as a water driven turbine.
How can you possibly say a solar panel of small percentage efficiency can compare to a steam driven turbine powerplant?

 

[Jadzia]

Hmmmmmmm. I mentioned in the OP about a space based colony having the energy beamed to them, I never considered having the powerplant actually attached to the space colony itself! The living area will be sheltered from the Sun of course.

Living that close to the sun, there would be other radiations to worry about. A shield can only do so much.

Astronauts currently use water walls to help protect them from solar radiation, but this is 150 million kms from the sun.

Oh, and while I'm here: There's a difference in meaning between solar panel and solar cell. This design is using a kind of solar panel.