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Colt
2003-Jun-27, 07:45 AM
This may seem like an odd topic but I can't figure this out on my own and I think it is pretty cool.

I remember seeing an episode of the Almighty Junkyard Wars a while back (not sure of the length of time) where they had to create windmills to grind coffee. One of the teams decided to use a type of vertical windmill which I thought was extraordinary. I had seen the type before but had always wondered how they worked. It was basically a metal pole which had some thin blades (sails) attached to the ends of struts going out horizontally with the blades being held vertically at the ends of the struts. They finally got around to explaining that theirs would work with the wind blowing from any direction. Very cool.

It was not until today when I started looking up some stuff about windmills for something that I am designing (might post it if I ever feel like drawing it :wink: ). In my search through Google I happened upon a website which talked about that very episode (http://www.channel4.com/science/microsites/S/scrapheap2000/4science.html) (Scrapheap Chal..?). I tried searching around to figure out how these things work exactly but all I am finding really are non-English sites which don't explain much.

This (http://telosnet.com/wind/images/tumac.gif) is what I am thinking about in this topic though, for Mars

I think that something like this could be used on Mars to help supplement power supplies along with a small nuke or solar cells (and to give it that first spin that it needs to start). That or put a normal windmill on top of it which points into the wind and gets the larger one going.

Well, that was an amazingly long post for me. Anyones thoughts on this? Of course the one which would be sent to Mars would be alot lighter and more advanced than the picture of the one I linked. Any information you can find about Darrieus windmills would be appreciated too. Thanks. -Colt

Humphrey
2003-Jun-27, 08:18 AM
I don't know how it works. Maybe like a planes wings, or more accurately, a helicopters blades?

But on mars it would be interesting. The dust storms probobly kick up a good wind, but outside of the storm is there sufficient wind to get it blowing for a long time?

Musashi
2003-Jun-27, 08:31 AM
Not to mention that the atmosphereic pressure is so low that even fast winds do not move the blades much.

If yo want an interesting (sci-fi) read on Mars, check out Kim Stanley Robinson's Mars series (Red Mars, Green Mars, Blue Mars). In the first book the team uses windmills to generate heat. I don't know how good KSR's science is, but it sounds convincing.

The Supreme Canuck
2003-Jun-27, 04:47 PM
There's another book in the series called "The Martians". Just so you know. :)

Colt
2003-Jun-28, 02:45 AM
Yeah, I am guessing that they work on the pinciple of lower and higher air pressures for movement, like a planes wings. Ones used on Mars would be pretty big and light so it would take very little to move them.

I have Green Mars and read it about four years ago, without knowing it was part of a series. Started to read Red Mars but got distracted. Does "The Martians" come after or before the other three? -Colt

The Supreme Canuck
2003-Jun-28, 04:05 AM
I haven't read the whole thing, but it begins with training in Antarctica and I thinks it spans the whole series. But, again, I never finished it.

DStahl
2003-Jun-28, 06:24 AM
On another site I once posted an idea for a Lethargic Power Generator, a generator driven from the daily expansion and contraction of methanol (or other fluid with a high coefficient of expansion) due to temperature changes. I called it lethargic because it operates at one cycle per day; on the other hand, it could develop tremendous pressure and, properly geared, give a generator quite a spin.

Probably get more electricity from solar panels, though.

Musashi
2003-Jun-28, 06:52 AM
The Supreme Canuck:

Red, Green, Blue, then The Martians, which is a collection of short stories. Good stuff, even if it is kinda hard to get into reading. I had the same problem you did with reading them. I read Red Mars and then tried to read Green but got distracted. A year or so later I repeated the cycle. Then, finally, a year or two ago I forced myself to read it straight thru.

Colt, I can't remeber how big they were, but I think they were kinda small and they used a whole lot of them.

KSR also qrote a neat series called The California Trilogy. Three books each with an alternate future for the world, and all three books taking place in my home town area of Orange County, California!

Humphrey
2003-Jun-28, 03:30 PM
On another site I once posted an idea for a Lethargic Power Generator, a generator driven from the daily expansion and contraction of methanol (or other fluid with a high coefficient of expansion) due to temperature changes. I called it lethargic because it operates at one cycle per day; on the other hand, it could develop tremendous pressure and, properly geared, give a generator quite a spin.

Probably get more electricity from solar panels, though.

How about using the moon and water? Would not the thawing and freezing of water each time it goes from day to night be more efficient than methanol?


[usual]

Sever
2003-Jun-28, 06:45 PM
The windmill in question was develloped by the canadian goverment to work in any condition regardless of the wind direction. I belived they did the thing you are talking about in Red Mars.

P.S does anyone remember the mylar in the trunk?

DStahl
2003-Jun-28, 08:49 PM
Humphrey: "How about using the moon and water? Would not the thawing and freezing of water each time it goes from day to night be more efficient than methanol?"

It might be, I don't remember the coefficients of expansion now. It's been a while. The good thing is that one can probably find a material to fit almost any given temperature range; the bad thing is that on a planet with long days and nights (like the Moon) the cycling of the "engine" is very lethargic! It was mostly a tongue-in-cheek idea, I'm afraid--it has the virtue of simplicty and that's about it.

The Supreme Canuck
2003-Jun-28, 11:52 PM
Musashi: Thanks! Now I get it...

DStahl: You could make it work by stringing a bunch of them along the equater so they cycle at different times and... uh... nope. I've got nothing. Maybe it wouldn't work after all... :wink:

Humphrey
2003-Jun-29, 12:09 AM
While on the topic of windmills, why do we not use the free high speed winds of the jet stream and the semi high winds of the trade winds? They are fairly constant and only shift positions during the different seasons (and extrodinary circumstances like El nino).

We could attach a windmill to a heavy lift ballon and keep it aloft. Then just send down the energy in cables that anchor the baloon to the ground. I imagine these windmills would be much more efficient than ground based ones.

-------

Side note: Does mars have areas of high speed winds like our jetstream?

The Supreme Canuck
2003-Jun-29, 12:46 AM
I'm pretty sure jet streams move. Take a look at the following link. The translucent line is a jet stream. Play around with the "Choose a Period" drop-down menu in the bottom righthand corner and watch the jet stream move.

http://www.theweathernetwork.com/weather/maps/floods.htm?sys

Kaptain K
2003-Jun-29, 01:00 AM
Just how do you expect to anchor this airborne generator? No matter how much cable you use, the jetstream is going to push it to the point where the balloon is just below the high winds that you are trying to capture. This assumes that you have enough lift to even haul all that cable that far. Sorry, it won't work!

Simon
2003-Jun-29, 01:04 AM
Okey... I've read through the whole Red/Green/Blue Mars series, and while I doubt Robinson's science is perfect (it's always fun to bend the rules a bit writing sci-fi :D) and a fair hunk of it is very speculative, it's definately within the relm of possible.


On another site I once posted an idea for a Lethargic Power Generator, a generator driven from the daily expansion and contraction of methanol (or other fluid with a high coefficient of expansion) due to temperature changes. I called it lethargic because it operates at one cycle per day; on the other hand, it could develop tremendous pressure and, properly geared, give a generator quite a spin.


Well... It's a pretty cool idea. But such a generator would probably have to be very large to be efficient. And how 'bout instead of waiting for nightfall for the working fluid to cool, you pump it through a radiator and let it get rid of some of it's heat that way? It would be quicker, and therefore let you heat more water, and generate more power.



How about using the moon and water? Would not the thawing and freezing of water each time it goes from day to night be more efficient than methanol?


Two things here... If you're on the moon, the cycle will be freezing and boiling, 'cause of the high daytime temperature. But this cycle will also take 28 days to complete, 'cause that's how long the Moon's day is sunrise to sunrise. That would be slightly more than a Lethargic Generator; more like a Comatose Generator...

*remembers what the original topic was* Oh yesh, windmills. Well, I would bet there's some kind of design problem inherent in the upright-rotor design, merely because I've seen lots of real electricity-making windmills in Denmark and Germany, and none of them used this design. I'll have to look into it more... It could be anything to some fatal flaw in reliability to an unjustified bad reputation.

Colt
2003-Jun-29, 01:58 AM
What about a Solar Boiler? The bottom part would be buried in the lunar soil witht the water sitting in it and when it is heated it moves a fanblade in the shaft and then cools as it passes and recondenses and returns to the bottom.. Eh. :P -Colt

Musashi
2003-Jun-29, 02:21 AM
What about exploiting the difference in temperature on the terminator? I read about this in some sci-fi book, I can't remeber what. They had railroad tracks around mercury and the cars would stay on the terminator and use the temp. difference somehow.

The Supreme Canuck
2003-Jun-29, 11:00 PM
That was in the "Red Mars" series. I thought they were trying to keep their settlement out of the sun so is wouldn't fry and out of the cold so it wouldn't freeze. But I could be wrong.

Musashi
2003-Jun-29, 11:07 PM
TSC, I think we might be talking about two sepreate scenarios. I can almost remember what you are referencing in the Mars trilogy, but my scenario was certainly from another book or series. I read too many books to always remember fine details :)

I think what I am talking about might be called a thermocouple, but I am not sure. I know that if you take most metals and heat them, the electrons flow away from the heat source, but in iron it is reversed, so if you tack together a piece of iron and a piece of copper, then heat one side, you get a current. Something like that anyways...

The Supreme Canuck
2003-Jun-29, 11:28 PM
Oh, a thermocouple, yes. Those exist now as a means of measuring temperature. If you do it right, you should be able to get a usable amount of elecricity from it.