DIY solar energy

[Havet]

Interesting article on an alternative way of gathering solar energy without buying photovoltaic panels.

SOLAR POWERED STIRLING ENGINE (http://digg.com/d1rmzX)



A Stirling engine (http://en.wikipedia.org/wiki/Stirling_engine) is a device that converts heat energy into mechanical power by alternately compressing and expanding a fixed quantity of air or other gas (the working fluid) at different temperatures.


Recently, however, stirling engines have been increasingly designed towards using another source of heat: the sun (http://en.wikipedia.org/wiki/Sun). New stirling engines can work using the heat of the sunand provide a new way for one to harness that energy without only relying on photovoltaic panels (http://en.wikipedia.org/wiki/Photovoltaic_panels).
Furthermore, stirling engines are very easy to make with simple materials

It also links to various websites where they show you how to make one from simple household items.


If you want it to be more environmentally friendly, simply use mirrors (http://en.wikipedia.org/wiki/Mirrors) in order to link the sun’s rays into the stirling engine’s heat sinker (http://en.wikipedia.org/wiki/Heat_sink).

[ÑóẊîöʼn]

Correct me if I'm wrong, but don't photovoltaics have a better performance under intermittent/sub-optimal conditions compared to concentrating solar thermal (which is what this whole focusing mirror-sterling engine arrangement is at the end of the day)?

[Delirium]

Nevermind

[Havet]

Correct me if I'm wrong, but don't photovoltaics have a better performance under intermittent/sub-optimal conditions compared to concentrating solar thermal (which is what this whole focusing mirror-sterling engine arrangement is at the end of the day)?

yes, i believe they do. However, how easily can you make one yourself? I think the stirling engine offers a great choice for those who find a photovoltaic to expensive an wish to take advantage of the sun.

[Vincent P.]

Wonderful!!! It's also easy to store energy into hydrogen to use it with a homemade fuel cell when it's rainy.

Thanks a lot.

[Coggeh]

Wonderful!!! It's also easy to store energy into hydrogen to use it with a homemade fuel cell when it's rainy.

Thanks a lot.
It is ? :mellow:

Oh sarcasm ... i knew that ... i think ..:blink:

[Vincent P.]

It is ? :mellow:

Oh sarcasm ... i knew that ... i think ..:blink:
Shit yeah it is :p.

[ÑóẊîöʼn]

yes, i believe they do. However, how easily can you make one yourself? I think the stirling engine offers a great choice for those who find a photovoltaic to expensive an wish to take advantage of the sun.

I was under the impression that, slowly but surely, as economies of scale gear up and more and more people are making use of solar panels, that prices were going down.

Although if a cursory Google search for prices is any indication, there are still a lot of rip-off merchants out there. Thanks a lot, capitalism. :rolleyes:

[Lynx]

I believe Stirling engines are the most efficient heat engines. Perhaps they are as efficient as photovoltaics?

[Vincent P.]

I believe Stirling engines are the most efficient heat engines. Perhaps they are as efficient as photovoltaics?
As a matter of fact, they're much more efficient than photovoltaics (speaking of the % of the sun radiations transformed into electricity). The only thing is that they would work in places with very bright sunlight (not like winter in Canada, where the sun never goes much higher than 20° habove the horizon), where photovoltaic cells would work a bit. But if you live in California, Florida or whatever you're the king of the hill.

Anyway they're much cheaper, so the $/watt ratio is much better. There is many kind of efficiency :P.

[Bitter Ashes]

Has anyone ever built one of these?

Looking at it, it seems to use pnematics to drive the pistons, which although would be quicker to heat, maybe lacks the power of using something denser like hydraulics which would allow you to see a more substantial power on a smaller scale.

A lot of hot gas would be required to inch that piston forward, while maybe only a small ammount of water, due to it bieng more difficult to compress before transfering the energy, would yield better results.

Maybe something as simple as a pair of two litre fizzy drinks bottles, with one wrapped in foil and one painted black could be used as containers. The pistons I'm wondering easy it would be to achieve watertightness though. Maybe you'd only need the one piston really and if you put that one on a pre-made hydraluic piston then the thickness and material of the container would be irrelivant if it's for the cold chamber.

Any thoughts?

[Vincent P.]

Has anyone ever built one of these?

Looking at it, it seems to use pnematics to drive the pistons, which although would be quicker to heat, maybe lacks the power of using something denser like hydraulics which would allow you to see a more substantial power on a smaller scale.

A lot of hot gas would be required to inch that piston forward, while maybe only a small ammount of water, due to it bieng more difficult to compress before transfering the energy, would yield better results.

Maybe something as simple as a pair of two litre fizzy drinks bottles, with one wrapped in foil and one painted black could be used as containers. The pistons I'm wondering easy it would be to achieve watertightness though. Maybe you'd only need the one piston really and if you put that one on a pre-made hydraluic piston then the thickness and material of the container would be irrelivant if it's for the cold chamber.

Any thoughts?

Well water is much harder to heat and cool (speaking of joules/kg) than air, so it may not heat/cool fast enough to give the thing a proper movement. Also heated air gain much more volume than heated water (which gains much more volume than heated metal).

[Havet]

Has anyone ever built one of these?

Looking at it, it seems to use pnematics to drive the pistons, which although would be quicker to heat, maybe lacks the power of using something denser like hydraulics which would allow you to see a more substantial power on a smaller scale.

A lot of hot gas would be required to inch that piston forward, while maybe only a small ammount of water, due to it bieng more difficult to compress before transfering the energy, would yield better results.

Maybe something as simple as a pair of two litre fizzy drinks bottles, with one wrapped in foil and one painted black could be used as containers. The pistons I'm wondering easy it would be to achieve watertightness though. Maybe you'd only need the one piston really and if you put that one on a pre-made hydraluic piston then the thickness and material of the container would be irrelivant if it's for the cold chamber.

Any thoughts?

I have attempted two built one, but I didn't succeed yet. It moved smoothly but somehow when the air inside the heat sinker was heated it didn't make my piston move. You have a lot of links on how to make it in the article though

[debase89]

oh damn yall got fancy science. I wish I had my own solar power tho maybe I'll watch this thread.

-debase

[Atrus]

I was under the impression that, slowly but surely, as economies of scale gear up and more and more people are making use of solar panels, that prices were going down.



From my own quick glance around some sites, I found this:




Solar installations will get cheaper with time, won't they?

Unfortunately the indicators are that price's will rise.

As a recent Financial Times article points out, the cost of energy, resources, materials and manufacturing is rising globally. It's likely that solar panels will never be cheaper than they are now as future panels and installations will consist of inputs {energy + materials} that cost far more than today.
Although we do our best to keep prices reasonable, their are customers we spoke to 2 years ago who wished they had bought back then.

Of course, that is from a company website, and they'd jump on any excuse to keep their prices high and make more profit, so I'm not sure how reliable it is.
Anyway, I thought that might be vaguely relevant.

[ellipsis]

You can make a solar oven with a pizza box and tin/aluminum foil. Or you can use water as a solar heat sink to partially warm a house.

[BrokenDown]

Interesting ideas. Especially since solar panels are so expensive.