1889 Solar Furnace

[Rigel Stardin]

This is a proof of concept, which I'm about to post to the art gallery.

The question I have is, is it possible for such a design to actually generator power in space?

 

[Carlobrand]

How are you maintaining attitude control? It's going to be very important to keep it pointed in the right direction.

 

[Rigel Stardin]

If the design can produce power in space, I'll add engines on booms.

At present, the design would have to constantly have to face the sun for maxium power. I might draw up a plan, where the solar mirror and steam generator are on a gimble. That would at least provide a 120 degree cone for manuvering while it can still maintain max power.

Batteries are not shown in this drawing and I assume there would be quite alot of them.

 

[Timerover51]

This is a proof of concept, which I'm about to post to the art gallery.

The question I have is, is it possible for such a design to actually generator power in space?

Based on a couple that are shown in books from Project Gutenberg, it would be possible to do in 1889. However, your steam generator at the focus of the mirror would actually be black-coated water tubes, not a circular boiler, and you would need a reciprocating steam engine to drive an electric generator for power, which I assume is the steam generator on the left-hand side of the drawing. In 1889, it would be a triple expansion plant, probably geared so as to be slow-running to reduce vibration. You would also need some form of control to compensate for the torque from the engine and electric generator. You will also need some extra water storage tanks to compensate for steam losses from the reciprocating engine.

Based on the 1889 date, your plant would put out power at the rate of somewhere between One Indicated Horsepower per 50 to 100 pounds of plant, as you would not have the heavy coal-fired boilers to deal with. One Indicated Horsepower would equal about 0.6 kilowatt hours.

Charles Parsons was working on the steam turbine, but was still a couple of years away from a functioning power plant. That would boost the efficiency of electric production per horsepower of turbine output, but you would still have the torque to deal with unless you used multiple turbines to process the steam, with the turbines running in opposite directions.

 

[Rigel Stardin]

Fast forward the design to present day.

Would the design provide enough power to run, an electro static drive?

 

[nyrath]

Enough to run an electrostatic propulsion system? Probably not.
You see, the generator is so massive in terms of kilograms per kilowatt generated, that by the time you scaled it up to the point it could feed an ion drive, the rocket's total mass would be such that the acceleration would be a microscopic fraction of a gravity. It would take several years to travel between Terra and Luna.

NASA looked into those things back in the days before nuclear energy. They used mercury instead of water, for efficiency. Such systems are generally useful for power needs between 20 kW and 100 kW. Below 20 kW a solar cell panel is better. Above 100 kW a nuclear fission reactor is better.

They typically have an alpha of 250 to 170, a collector size of 130 to 150 watts per square meter, and a radiator size of 140 to 200 watts per square meter. (where "alpha" is how many kilograms of generator you need to produce one kilowatt)

By the way, you forget to include the heat radiator.

There is a design for an emergency maneuver drive called a "solar moth"
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Beamed_Power--Solar_Moth
It is basically a half-silvered balloon used as a mirror to heat up propellant that is expelled from an exhaust nozzle.

The advantage is that it is so cheap and low mass that any ship can afford to have one as an emergency back-up.

The disadvantage is a single Solar Moth engine has a pathetic thrust of 4,000 Newtons. This means if the ship has a mass of 100 tons (not dtons), a Solar Moth engine could give it an acceleration of 0.04 meters per second, or about 0.004 g. Which is still better than the steam engine feeding an ion drive.

 

[Vladika]

The disadvantage is a single Solar Moth engine has a pathetic thrust of 4,000 Newtons. This means if the ship has a mass of 100 tons (not dtons), a Solar Moth engine could give it an acceleration of 0.04 meters per second, or about 0.004 g. Which is still better than the steam engine feeding an ion drive.

Hence the need to "discover" ether...

Thank you for the fascinating link!

 

[atpollard]

Since the subject of a fission reactor has been brought up, I always wondered about the possibility of partially enriching a fissile material to manufacture something like (but different from) a Radioisotope Thermoelectric Generator ... natural radioactive decay provides heat to boil water ... then the standard Victorian/Edwardian Steam technology takes over.
I always liked the concept of a steam train that needs no wood/coal.
This spacecraft could be another application for a "nuclear boiler".

 

[Vladika]

Since the subject of a fission reactor has been brought up, I always wondered about the possibility of partially enriching a fissile material to manufacture something like (but different from) a Radioisotope Thermoelectric Generator ... natural radioactive decay provides heat to boil water ... then the standard Victorian/Edwardian Steam technology takes over.
I always liked the concept of a steam train that needs no wood/coal.
This spacecraft could be another application for a "nuclear boiler".

"Scotty, fire off the boilers, we need the weapons online now!"

"No kenna do it in under 4 hours captain.":toast:

Seriously though, an interesting concept.

 

[Rigel Stardin]

I found this 10 Mw Steam Turbine Generator online:

http://www.alibaba.com/product-detail/10-MW-Steam-Turbine-Generator_140251477.html

Weight for this generator minus coolant is 24 tons.

Since I didn't sleep at a Best Western last night, and such things are beyond my pay grade, let's say it's 50 tons for the total package. The issue then becomes how big are the thrusters? If we are talking another 25 ton+ we have a system somewhere in the range of 75 to 100 ton range. How big a payload could such a system then have? I have no idea on how to scale up thrusters from their present size or how to calculate there efficiency, and power requirements?

As far as the Steam turbine goes, are there not plastics and light weight composites that can replace the alloys now used? The one I sited is from 1992. Weight reduction to the generator would make a great difference in the overall weight.

One thing, this would be a thruster/coast system which wouldn't provide constant thruster.

 

[Drakon]

One big worry concerns gravity. Fluid flow through a steam plant uses the higher pressure steam for part of its travel, but once it is back to liquid form, you will need to make sure your pumps keep the fluid moving. Most earth based plants use gravity feed to collect the condensate. Essentially a series of cooling tubes that steam exhaust from the turbines (or reciprocating engine as mentioned elsewhere) gets dumped on top, and collection of the liquid at the bottom.

It is not a big engineering challenge to design for space, but it is something to keep in mind. If you make the plant so that it will work just as well upside down as right side up, you should be good.

 

[Drakon]

I found this 10 Mw Steam Turbine Generator online:

http://www.alibaba.com/product-detail/10-MW-Steam-Turbine-Generator_140251477.html

....
As far as the Steam turbine goes, are there not plastics and light weight composites that can replace the alloys now used? The one I sited is from 1992. Weight reduction to the generator would make a great difference in the overall weight.

One thing, this would be a thruster/coast system which wouldn't provide constant thruster.

For turbine blades? I don't think this is the place for weight reduction, especially if you are doing this in 1889. The environment is not ideal for plastics, a steam turbine is high temperature and high pressure environment.

Aluminum tubing for most of the piping would be okay, I think. But you want something that can withstand the heat, rotation and pressures involved for turbine blades. And you want to watch the alloys you use in the steam generator, as those pipes are in a high stress environment as well.

Another issue is water chemistry. How well does any new material work when exposed to extremely hot water and steam, in the vacuum of space?

 

[nyrath]

Hence the need to "discover" ether...

Thank you for the fascinating link!

Thank you! The link is to my website.