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Why don't we see more solar powered Stirling engines in the market? Seems the only solution is DIY. They're much more efficient than solar panels, they last much longer, and when they break down, you just have to repair a motor instead of throwing the whole assembly into the landfill.

https://ieeexplore.ieee.org/document/6129723

pic related is a 10kw unit, I think, costing approx $150k in early 2000's. There's a deployment in Cali. http://www.stirlingenergy.com/

Has here anyone ever tried to deploy their own solar stirling engine for power?
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>>2160433
Probably the easiest DIY solution is a fresenel lens and a tiny hobby Stirling engine, this setup can generate 50-300 watts.

https://www.youtube.com/watch?v=5pdqDQwehlk

A much more powerful solution is to repurpose a satellite dish and use a larger stirring engine made from milled aluminum.
https://www.youtube.com/watch?v=EahfGfDdgNY

It's also possible to make a flat panel stirling engine for roofts, pic related. The small project doesn't produce very much energy however but is very cheap to produce, requiring no special tools.
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>>2160439
Link for flat panel project, unfortunately there isn't much information on the construction, but if you've built a hobby Stirling engine before and watch the video closely, I don't think it would be very hard to clone.


https://www.youtube.com/watch?v=8QE-CmKxz40
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>>2160433
If I have to make an educated guess, then it's due to high complexity, scalability, and maintenance. Solar panels have shit ass efficiency compared to the theoretical efficiency of a Stirling engine, however they're very simple devices, they're basically maintenance free, they're modular, they can scale up or down almost indefinitely, they benefit directly from economy of scale, and there's a lot of research pushing the technology forward. At an industrial level anything other than photovoltaic (and wind) is uneconomical, mostly. Photovoltaic is not feasible for your average /diy/, but everyone can cobble together a bunch of mirrors/lenses and a thermodynamic cycle hence why you see those solutions applied there.
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>>2160510
Yes but I’m hoping that the Stirling engine will have a longer lifespan then the solar panels. Sterling engines don’t require any maintenance but they of course have moving parts so I imagine that they would break down eventually, but when they do break down you can fix the motor restoring the whole system to like new performance.
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>>2162370
The only problem is getting your hands on a refined Stirling engine. The kind that could last decades with little or no maintenance
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Microgen-engines.com
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>>2162370
Well and consider that you can use the output of the stirling engine to create another stirling engine on the spot, so when one goes out, the owner can make one from iron or aluminum or even wood parts if necessary. PV cells are way more complicated to create at home.
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>>2160433
get on my level, scrub
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>>2160433
>Has here anyone ever tried to deploy their own solar stirling engine for power?
I really want to do this, and run it off waste heat from my garage roof. I suppose the trade-off is that it has to be a big machine with a lot of torque that runs slowly assuming the heat difference I could get, but that's no big deal. The problem is how to make well-fitting pistons with the diameter of an oil drum by yourself, or how to get a big flywheel. Anyone know of any off-the-shelf parts that might do the job?
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>>2162370
>I’m hoping that the Stirling engine will have a longer lifespan then the solar panels.
They may do, but
>Sterling engines don’t require any maintenance but they of course have moving parts
Whenever you have moving parts you have extra maintenance to do, or you run the risk of shortening the life span of the device, not to mention the decrease in efficiency.
>so I imagine that they would break down eventually, but when they do break down you can fix the motor restoring the whole system to like new performance.
You can prevent breakages by performing regular maintenance and checkups.
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>>2162529
explain concept pls
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>>2160433

I've done a lot of musing and more than a little research on various types of hot air engines (particularly closed-cycle engines and organic Rankine cycle engines), and running them off solar. It's very likely I'll make at least a small one, if I can ever find a spot between projects to do it. The two biggest issues with using solar to drive any type of hot air engine are the fact that they require _perfect_ conditions to get decent power out of, and they're mechanical devices.

Unlike solar panels, which can operate at least "okay" on an overcast day or when they get dirty, the reflector of a solar engine requires both direct sunlight and to be kept very clean. Anything that interferes with a coherent reflection onto the collector surface trashes the efficiency of the system.

Also unlike photovoltaics, a hot air engine is just that: An engine. It requires maintenance. Depending on how well it's made, it may not be very much, but it's more than the simple cleaning that solar panels need every now and again. Which, remember, the collector/reflector will also need.

Perhaps the greatest irony is that, even if you can hassle with the entire collector assembly, you're arguably _still_ better off not using the engine, and just doing concentrated photovoltaic instead.

The only real advantage I can come up with in the engine's favor is that it doesn't require a semiconductor fab to make. Given that this is only relevant in some extremely niche cases, it's little wonder why solar engines aren't seen often.

I guess you can repair an engine, too, unlike panels which have to be replaced, but again, given how the masses would actually use these things, doesn't really count for much.
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How hot can you get with an array of mirrors anyways? Hot enough to ignite wood and such in bright daylight sure but even that seems like a low temperature difference for an engine. PV also has the nicety of relatively constant voltage while a heat engine's RPM will vary massively with the irradiance, so you will get additional losses from the transmission equipment depending on the use of course.
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>>2163432
>How hot can you get with an array of mirrors anyways?

About 5,800K. The theoretical upper limit is the "temperature" of the light source being used (in this case, the sun). Don't ask me why, I don't actually know.

In more practical terms, though "hot enough" is a good answer.
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>>2160433
I bought a bunch of shit off the bankruptcy auction from your pic related manufacturer.

PV panels costs about $0.10 per watt these days. Unless you have absolutely no option but solar in extremely high land value area there is no reason do do any kind of solar other than fixed PV. If your land values are very high and you need solar then you can start looking at tracked PV or concentrated PV. Only a retard tries to get electricity from solar thermal these days.

Solar thermal is fine for hot water, heating homes and pools but even then its the cheaper tube within an evacuated tube solar thermal not this tracking bullshit.

Maybe maybe heliostats could be viable for industrial processes that need heat energy directly, perhaps a solar kiln for cement or ceramics or the like. But they are not a viable for electrical power generation. Fixed PV is just way too cheap to do anything else.
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>>2160433
When your buying pv by the shipping container 10kw costs only $1,000 - $4,000 compare that with your $150k abomination to see why no one does it.
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>>2164544
It's because, if we idealize both the sun and the object being heated as perfect black body radiators, then when the object reaches the same temperature as the sun, it will be glowing as much as the sun is. The mirrors and lenses wouldn't be redirecting light in any direction anymore, because for as much energy as they reflect from the sun to the object, they would also be reflecting light from the object to the sun in reverse.

To make it hotter, you would need some kind of mirror that would reflect light from the sun to the object, but when light comes off the object and hits the same mirror, it would have to be sent back to the object. This is not possible with any kind of passive system.

Neither the sun nor the object are perfect black body radiators, but they're close enough to one.
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>>2164572

Had to look into it further, because reasons.

This answer is not wrong, but incomplete. The much-simplified answer is that there is a limit to how small a lens can make an image, and it's partially based on how big the lens itself is (even ignoring physical limits, like refractive index).

It makes sense that you can't heat up a black body radiator with another one of a lower temperature, but it's not really intuitive that you can't focus light to an arbitrarily small point, since most every diagram of a lens shows them doing exactly that at some point.
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>>2163417
i think the head heats up and produces a stove effect
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>>2164572
How does someone as stupid as you operate a computer?
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>>2165190
If that explanation doesn't make sense to you, you're the brainlet here.
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>>2160433
Because solar generation is a shitty fucking meme and even the best panels have a half-life of 5ish years.

The only truly effective "solar" design is a heated water/steam driven turbine tower like the one out in Nevada, and that uses mirrors not solar panels.
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>>2165263
>doesn't understand how light or reflection works
>calling anyone else an idiot
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>>2165277
Then stop being an asshat and explain what's wrong with.
>inb4 not gonna tell you
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If engine complexity and maintenance is an issue, you could consider thermoelectric generators (reverse peltier cooler).
It would only be equal or more effective than PV if you had a cold source to go with it, e.g. placing the dish next to a river and pumping the water into the radiator.
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>>2162529
>5km tall mushroom generator
what?
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>>2165276
Are you retarded? How did you figure out how to post?
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>>2167383
That picture doesn't show the large 'greenhouse' around the bottom of the tower which acts as a solar collector. The solar updraft tower is a simple enough idea-- greenhouse heats air, then it goes into a tall chimney-like tower. As it rises, the air becomes less dense which increases its volume and thereby, it's effective speed. At the entrance to the base of the tower there are turbines to generate power from the moving air.
With this mushroom, the tower is constructed of lightweight fabric such as hot air balloon material. The mushroom head on top has downward pointing jets and the air moves so rapidly up the tower that it will keep the head lifted by the downward force created as air flows through the nozzles.
This allows the entire apparatus to be built on really shitty useless desert land using cheap materials while generating tons of power.
A couple of the engineering challenges that /diy/ is going to face here is that we will have to build what is by far the tallest man-made structure ever created, and that the weight of the unit as it is initially lifted into place to begin operating will require a hot air balloon the size of which the world has never seen, or some other unconventional lifting strategy. The air will be moving at an enormous speed, approx 300mph, by the time it reaches the top of the tower.
You're looking at ~130 megawatts for a 20m wide tower
superchimney.org
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>>2162370
>Sterling engines don’t require any maintenance
retarded or just rolling?
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>>2167409
wow very interesting, a 5km mushroom would look so sci-fi. But the calculations on the website look very optimistic 70C on the bottom and -20C at the top would produce 147 tons of lift.
But what about at night when the temperature can drop to -5C in the desert, at that point a small gust of wind can make it crash
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>>2162371
acoustic science, and piezo electricity generation from said field is not a very well established field



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