Mini solar tower

[Steven Dufresne]

My two cents:  I think your solar tower is to short.  In order to get a better flow and pressure difference you could try more length, i do not think you will get any noticeable "torque" with such a short heating collector , which is as I understand open at both sides. 

See it as a chimney, it needs a certain length to work best.

Help me understand this then. There are three areas: the area where the absorber is and the air is being heated, a length of pipe below it, and a length above it. Which are you suggesting be longer? I've never worked with chimneys of any kind before.

One commenter in the video for versions 1, 2, & 3, archeryman5000, said to think of the hot air as like a balloon, I want a larger mass of it moving upward to create more lift so he suggested making the length above longer. Makes sense to me. Is that what you mean?
-Steve
http://rimstar.org   http://youtube.com/rimstarorg

[Cherryman]

Help me understand this then. There are three areas: the area where the absorber is and the air is being heated, a length of pipe below it, and a length above it. Which are you suggesting be longer? I've never worked with chimneys of any kind before.

One commenter in the video for versions 1, 2, & 3, archeryman5000, said to think of the hot air as like a balloon, I want a larger mass of it moving upward to create more lift so he suggested making the length above longer. Makes sense to me. Is that what you mean?
-Steve
http://rimstar.org   http://youtube.com/rimstarorg

Well i'm not an expert either, but see it as reversed gravity.

If you have a long hose, filled with water, hold it vertical, the longer the hose, the more pressure there will be at the bottom, and thus force to get out.  ( At the other end a sucking force will be created )

Heated air acts the same, but the instead of going down, going upwards.

So the bottom part has to be a little longer to prefend escaping air downwards ( As you put up resistance at the top)  and the above part has to be even longer, so heat accumulates and takes up speed and "mass" before entering your generator.

I hope this makes a little sense.

[Steven Dufresne]

@Cherryman,
Thanks for clarifying. Makes sense to me and I have just the tube, a 1 1/8" ID by 34" aluminium tube I picked up from Home Depot a long time ago. You can see it and the copius amount of Roxul insulation I recently bought in the photo below. I'll make it all today and hopefully the sun will come out sometime in the next few days to test.
-Steve
http://rimstar.org   http://youtube.com/rimstarorg

[ResinRat2]

Hello Steven,

Thanks very much for sharing your project.

Are you basing it off the larger experimental solar towers like:

http://en.wikipedia.org/wiki/Solar_updraft_tower

It looks like in these larger ones the bottom area around the tube is heated and the air updrafts into the tube naturally.

Good luck with your work, thanks again for sharing.

RR2

[Steven Dufresne]

Hello Steven,

Thanks very much for sharing your project.

Are you basing it off the larger experimental solar towers like:

http://en.wikipedia.org/wiki/Solar_updraft_tower

It looks like in these larger ones the bottom area around the tube is heated and the air updrafts into the tube naturally.

Good luck with your work, thanks again for sharing.

RR2

Thanks RR2.

Yup. I got the idea from those huge solar updraft towers.

I did some calcs this morning and using the aluminium tube I mentioned above and assuming the temperatures I measured with version 4 and assuming no losses I should get a stack effect draft/draught flow rate of 9.375 cm^3/s. That's a cube of air around 2 cm per side every second. It's not much but it's enough for me to continue. I got the formula from:
http://en.wikipedia.org/wiki/Chimney

-Steve
http://rimstar.org   http://youtube.com/rimstarorg