anyone ever make any solar power thingys that actually worked?
I have been planning a stirling engine, powered by a solar collector, and was looking for clues
I have quite a few LARGE mirrors I was gonna cut up, to make a "troth" type collector for the "hot" side of the engine, and bury something like a radiator in the ground for the "cold" side. I was also thinking a second "cold" collector, above ground, for winter use

I made some small hobby stuff, but I don't know how well solar cells can do with a stirling engine. I've known somebody that made a small one, but he used a kersone lamp for the heat.

I hear the government gives some kind of rebate for having alternative energy in your home. Since we get more than our share of sun here in Houston, I'm thinking...

...

... yeah.

Well... I once took a solar panel and added it to the perimeter line generator for our robomower... it worked, so long as the mower wasn't running long enough to cause a shadow to hit the panel...

Yeah, it kinda sucked. Solar isn't that great a technology. Don't expect it to power your house... but if you cover your roof in panels you might be able to power your computer!

I can think of two good (practical) current applications of solar energy...

1) Heat water
2) light up those sidewalk runway lamps that use LEDs. (OK, maybe this isn't good - but it is practical.)

Obviously, humungus collector panels can be used for direct electrical generation - but you have to be the government to do such and even then they are only used where other means of power generation isn't available.

Current research is leaning towards using photovoltaics to split water and generate hydrogen (the oxygen is wasted to the atmosphere). Hydrogen is stored in a fuel cell and used on demand to be burned with air. Still quite a ways for this to be viable, but it can make for some good research.

well, to start with - "solar panels" that directly convert to electricity - not what I looking at using. but - for those intrested in them - they are free on road construction site all over the place - they be lighting signs. just pull up, hook to your truck, and take it home. they are worth roughly $300 for just the panel, and they also come with a battery. 10 of these will run a normal household - with the addition of a $1500 dollar power invertor - which also lets you "sell back" power. most places with good sun, also have a daytime premium for electricity - so, you better off selling your daytime juice, and using powergrid juice at night.

anyways - what I am looking for is more info on heating water/antifreeze - looking for 200*. for the "hot" side of the stirling engine.
and, if anyone has help with a good stirling engine design. looking for what size pistons (ratio) to use for a roughly 200* hot, 60* cold - I am thinking 4:1. is there a particular gas that expands more than another in temp changes? (like - nitrogen - very resistant to expanding form temp change - why good for tires)

quote Originally posted by Pyrthian: anyways - what I am looking for is more info on heating water/antifreeze - looking for 200*. for the "hot" side of the stirling engine. and, if anyone has help with a good stirling engine design. looking for what size pistons (ratio) to use for a roughly 200* hot, 60* cold - I am thinking 4:1. is there a particular gas that expands more than another in temp changes? (like - nitrogen - very resistant to expanding form temp change - why good for tires)

Not familure with the stirling engine. Will have to look that up.

Questions.. What if the "gas" you choose actually boiled between 200 & 60 (and I assume you mean F)? That's some pretty heavy duty expansion there, but perhaps the stirling must utilize gas on both low pressure and high pressure sides.

Can you use a Frenzel (spelling?) lens to heat the hot side?

Also, what pressure do you expect to be running at?

Heading off to learn about the stirling...

quote Originally posted by RTNmsds: Not familure with the stirling engine. Will have to look that up. Questions.. What if the "gas" you choose actually boiled between 200 & 60 (and I assume you mean F)? That's some pretty heavy duty expansion there, but perhaps the stirling must utilize gas on both low pressure and high pressure sides. Can you use a Frenzel (spelling?) lens to heat the hot side? Also, what pressure do you expect to be running at? Heading off to learn about the stirling...

if it boiled between 60 & 200 (yes, F) I think a turbine would be a better use of the expansion, and that would be good too.
not sure what a frenzel lense is. I have some big mirrors, and was thinking - since I got 'em....use em...solar collector - or bedroom ceiling....
and pressure - whatever pressure is created when a gas is heated from 130* to 200* and whatever vacuum is cerated by the same gas cooling from 130*to 60*

yes, the stiring engine is a pretty cool hunk of stuff. a really impressive design is a 4 cyl rotary design. the design in my head has 2 displacement pistons running a single power piston, one on each side. this way the 2 displacement pistons can counterbalance each other, and the power piston will be pushed & pulled at the same time. being I have such a low temp difference, it wont be very strong. so, I am thinking the power piston will have to be at least 4 times smaller than the displacement pistons. maybe even 5 or 6 times smaller. but, my real concern is finding a good gas to use. the key property is how much it expands & contracts, due to temp change, especially in the 60* to 200* range. boiling/condensing wont be good, because I dont think I can make that happen fast enough.

>< bump ><

also, planning on using MAP sensors to manage cylinder pressures & CTS sensors to monitor the hot & cold fluid temps. gonna need to make a interface to a PC. something to read the 6 MAP sensors, one on each displacer cyl & 4 CTS sensors (2 right now - but other heat & cold sources are planned for future use). and, use this info to control 6 valves on the displacer cyls & 2 valves for the pressure/vacuum supplies.

with varying hot temps through the day, and being there will always be some leakage from the seals, cylinder pressure will need occasianal adjustment, for long term efficent running.

sofar, looking at roughly a 3 CuFt displacement piston against a 0.5 CuFt power piston. with the lower temp difference, I am assuming a bigger ratio of displacement vs power. and, with 2 displacement pistons against 1 power piston, I should be able to get some reasonable power to spin an alternator, to make the 12v, which then heads off to the invertor.

stirling engines dont really "rev" to high, so I will need to gear up to get decent RPM at the alternator. I have absolutely no clue what the actual RPM will be at peak temps & average temps. I am guessing at best 500 at peak. and, I'd like about 3000 rpm at the alternator.