Low Temperature Differential Stirling

[Geof]

Actually I made a goof it was 37' diameter, not 37 sqft. Some claim 30% conversion efficiency these days on solar to motive via stirlings

I take 30 with a grain or two of salt but on a big installation yes maybe. The problem is you need focussing collectors; I think they do it direct focused solar onto the Stirling. For a small scale version possibly a stationary parabolic trough collector heating water which is the heat source for the hot side of the Stirling and for the cool sink have another water loop through ground pipes. Not unimaginably complex for diy.

[mdreitzusa]

heres something that might help
A TRACKING SOLAR CONCENTRATOR (diy)
http://www.ida.net/users/tetonsl/solar/solarhom.htm

[pminmo]

Yeouch, 1200 degrees, no wonder they no longer publish the manual with todays liability ambulance chasers. I think my neighbors might complain....
I'm still trying to grasp power verses temperature differential. Using a ground loop for cooling you should be able to keep a cold side 60 degrees or less. A simple box solar water collector I believe will do 150 degrees or so. I wonder if that is enough?

[Geof]

I had a look at the Teton collector and it looks like an idea I had using a lot of CDs attached to a frame all focused on the same point. But the problem with a focusing collector is moving it and making it strong enough to withstand wind or snow loading.

Regarding temperature differential and power they are related but not directly. How much power is available is, of course, dependent on how much sunlight your collector intercepts. How much power you get out of your Stirling depends on the temperature differential between the heat source and the sink because the thermodynamic efficiency depends only on this differential. A small area focussing collector will give a greater temperature differential than a larger non-focussing so because the efficiency is higher your output power from the smaller collector could be the more.

You need to find someone with a stash of 'Mother Earth News' dating from the mid to late 1970's and read all the articles on alternate energy sources written by and for the hippy era back-to-the-landers.

[vacpress]

so.. in edmund scientific, when i was young, i would often gaze at the giant fresnel lenses. they claimed that one of their 36x36" fresnels could 'melt concrete', whatever that means...

anyhow,anyone considered fresnels as opposed to parabolic concentrators?

also, there are tons and tons of DIY solar concentrators on the internet. As well as many DIY solar power controllers, solar trackers for concentrators, and other interesting do-hickies....

if someone was really interested in an opensource project of this type, i can donate some web space and set up a community for it.. i hate the way we are ruining the environment.. it makes me literally want to cry... and worse still, i now work in 'the power industry'... cringe.cringe..

i have a development project at http://development.1318cermak.com

this is sort of like what i could setup for a solar generator open source project... most of the meat is in the private portion, and my work internet wont loginto it for some reason, but it has file bases, message boards, etc... based on the fabulous Joomla...

Robert

cheerio

[pminmo]

I'm in, "colaboration tool" is new to me, but could be awsome. where do I look for one?

[pminmo]

regaring fresnel lenses vs a parabolic. A parabolic will reflect even non visable IR, will a fresnel focus non visable IR?

[Geof]

regaring fresnel lenses vs a parabolic. A parabolic will reflect even non visable IR, will a fresnel focus non visable IR?

Probably not; most plastics and glass absorb infrared. This would not be a great loss because the portion of solar energy at ground level that is in the infrared range is not large. It is possible a greater loss would come from surface reflection on the fresnel but this would depend which side was facing the incident radiation.

[fkaCarel]

Reading this I remembered what our French friends made in Odeillo in the Pyrenees. It's a monster solar tracker (1Mw). On google I saw mentioned that there is also Stirling technology involved. The only thing is, that if you search in French, you get better response than English.

http://fr.wikipedia.org/wiki/Image:F...meu_France.jpg

Carel

[fkaCarel]

And searching a little further you stumble on the "Eurodish", a solar/Stirling project of the EEC. Here is the site of the producer:

http://www.stirling-engine.de/engl/index.html

Carel

[Geof]

Reading this I remembered what our French friends made in Odeillo in the Pyrenees. It's a monster solar tracker (1Mw). On google I saw mentioned that there is also Stirling technology involved. The only thing is, that if you search in French, you get better response than English.

http://fr.wikipedia.org/wiki/Image:F...meu_France.jpg

Carel

I believe this one was done for experiments in making ultra-pure high temperature alloys.

[vacpress]

I'm in, "colaboration tool" is new to me, but could be awsome. where do I look for one?

here: http://www.opensourcecms.com/

i suppose those links i just looked at intimidated me... for some reason, earlier in the day, focusing some sun on a sterling type generator seemed totally logical and 'easy'... when it is overcast, just use the power that is 'stored'(somewhere).

i suppose, unfortunately, a opensource solar generator of any use is rather unlikely to emerge soon, considering the (insert cliche method of indicating 'strangle hold'(get it), here). especially involving me, since i still havent finished most of the projects ive started(but geeze, ive learned alot).

so, a altpower.opensource.1318cermak.com(or similar, 1318cermak.com just being a domain i own and dont mind using for such things) would be easy for me to setup. i will do it. however, i dont have much to contribute.. all i know is that between the sun, wind, tides, and other gravity or celestial related energy is probably way more than enough to sustain us.. plus then we could kiss muslims on the cheek and all agree that it's rad that cars are quiet and electric, now that we have finally used fresnel lenses to make stirling engine-driven generators power everything...

please, please, show interest..