the Otherpower.com Discussion Board || alternate mill for the vertically challenged

Front Page - [Homebrewed Electricity-- (wind) (solar) (hydro) (steam) (controls) (storage) (mechanical)] - Classifieds - Site News
Everything - Newbies - [Remote Living-- (housing) (heat) (light) (water)] - Rants & Opinion - Diaries - Our Products

alternate mill for the vertically challenged
By bob g, Section Mechanical Posted on Fri Aug 31st, 2007 at 06:54:13 PM MST
been thinking of what happens when the sun beats down on a pipe

and then i got to thinking what if the pipe was perhaps 20 inches in diameter
and a hundred feet long
i have a slopping hill behind my place that is exposed to the summer sun very well
so what if i took about 30 or 40 fifty five gallon barrels, cut the tops and bottoms out, tack welded them together and laid the pipe up the hill, paint it flat black so it gets good and hot in the summer sun.
no i got to believe that there will be a rather fast moving air mass climbing up that pipe.
then i got to thinking that maybe a multi blade turbine could be made to fit in the pipe, on the intake end
sort of like a big vacuum cleaner drawing air through the turbine, and betz has no limitation here as i see it.
i figure it might produce a kwatt or so a day in the summer,, and because i am vertically challenged (i hate heights) everything is down on the ground.
i guess if it worked one could put up multiple tubes up the hillside?
anyone ever seen one done by a diy'er?
bob g

alternate mill for the vertically challenged | 7 comments (7 topical, 0 editorial)

Re: alternate mill for the vertically challenged (3.00 / 0) (#1)
by altosack (altosack-at-yahoo-dot-com) on Fri Aug 31st, 2007 at 01:09:38 PM MST
(User Info)

Hi Bob,

It's a good idea, and similar to one I had a couple of years ago. Will, mine was a good idea until I ran the numbers.

I was interested in the Solar Power Tower, which is a 1km tall tower with a (I'm not sure what, probably about 3km)-diameter greenhouse underneath. The solar heat from the greenhouse heats the air, which then rushes up the pipe to provide power through a turbine mounted inside the tower.

My thought was that if I did everything myself out of scrounged materials on a smaller scale, I wouldn't care that much if the efficiency wasn't very good. Well, it turns out that I just won't get enough velocity from the temperature difference (minus the friction loss) to make it worthwhile (my plans were for maybe a 20m tower on a 20m diameter greenhouse, or whatever would work). In addition, it would be too hot in the greenhouse for growing anything (they don't have this problem so much in the scaled-up version).

I don't remember the exact numbers, and I haven't run them for your idea (which needs a higher temperature differential because it wouldn't be vertical), but trust me that it won't be satisfactory.

Best of Luck and don't stop the ideas,
Dave Voss

Re: alternate mill for the vertically challenged (3.00 / 0) (#2)
by mikeyduk on Fri Aug 31st, 2007 at 01:12:32 PM MST
(User Info)

Some years ago an article in New Scientist had an article on using this setup
for passive air conditioning in hot countries.
Several drums welded together ( same as your thoughts ) connected to a hole in the house wall to draw air through.
Also there were tests done in israel ( I think ) using a monster tower to do much the same thing.
They had to drizzle cold water from the top in order to provoke an adequate airflow to turn a turbine.Not sure of the results,it was a long time ago and I never heard anymore about it.
Not much good in the UK.
Anyone got a genny running on rubbish weather generated misery and depression :(

Regards
Mike

Re: alternate mill for the vertically challenged (3.00 / 0) (#3)
by Ungrounded Lightning Rod on Fri Aug 31st, 2007 at 01:35:40 PM MST
(User Info)

You're talking about a heat engine - and not a very good one.

If you're going to lay out that much black sheet metal, why not make it thin copper sheet with a loop of copper tubing behind it and fill it with water (or antifreeze soluteion?) Put a little insulation under it and some glass over it.

Then you can collect the heat at a higher temperature, pipe it to an efficient heat engine, and perhaps use some of it through a heat exchanger to heat your water and house.

Re: alternate mill for the vertically challenged (3.00 / 0) (#4)
by bob g on Fri Aug 31st, 2007 at 01:58:29 PM MST
(User Info)

first of all i am not looking for efficiency per se
there is something to be said for simplicity is there not?

barrels are given away if they are damaged in many area's
and a small turbine is fairly easy to construct and fit within either
the pipe of a funnel/manifold connected to either one or several of the pipes.

i don't know about the rest of you guys, but have you ever been on the upside of an irrigation or drain pipe in the hot kansas sun in the summer time,, the airflow
is like a blast furnace and come out with some force, and they arent black, very large in diameter or as long.

my question isn't how inefficient it might be but rather if anyone has seen any reference to anyone trying it?

fair enough?
:)

bob g

[ Parent ]

Re: alternate mill for the vertically challenged (3.00 / 0) (#5)
by rippersoftware on Sat Sep 1st, 2007 at 06:45:03 AM MST
(User Info)

Take the barrels and make several savonius VAWT and gear the output shaft to spin a generator at 2,3,4 times the shaft speed. Put the VAWT into the windy area and make some juice. Check out the Australian sites. They have become pretty good at this.

RipperSoftware

Re: alternate mill for the vertically challenged (3.00 / 0) (#6)
by rippersoftware on Sat Sep 1st, 2007 at 06:48:46 AM MST
(User Info)

Here is a good collection:

http://www.southcom.com.au/~windmill/

RipperSoftware

[ Parent ]

Re: alternate mill for the vertically challenged (3.00 / 0) (#7)
by jmk on Sat Sep 1st, 2007 at 08:59:21 AM MST
(User Info)

You would have to change your rotor into a fan like what is used in for an attic fan or engine cooler. Other wise your heat would keep going straight up. I think it would work. You might be better off compressing air that is air tight and then releasing it. This would work great with the sun because of the work force would be there when the heat is. It doesn't take a lot of presser to bring in your heat. It would work a little bit in a air tight tube only venting into your house without a compressor. Put a water pumper wind mill on a compressor and it will blow hot air.
jmk

alternate mill for the vertically challenged | 7 comments (7 topical, 0 editorial)

Menu

� create account
� How to use the board
� FAQs
� search the board
� Google search the board
� Old Otherpower Board

Login

Make a new account

Username:

Password:

Total Views

��173 Scoop users have viewed this posting.

Related Links

� Also by bob g

You must be a registered user to post here. It's easy and free, and the link is on the upper right side of your page.
All trademarks and copyrights on this page are owned by their respective companies. Postings are owned by the poster, but may be deleted or moved at the ADMIN's sole discretion. The Rest � 2003 Forcefield.
You can Email the board ADMIN here. PLEASE include the username you signed up with!