3KW Stirling Engine - Pics provided

[yellow88fiero]

Good to know about being able to manufacture the parts cheap. Is the expectation that you can buy one of the canisters from walmart/target and hookup to your new high pressure pump to be able to get the levels needed to fill it? I thought the high pressure tank would just take the air and not be able to hookup to another tank. If you can, that is cool that you can pressurize your own helium from the other balloon tanks.

[Tom Booth]

Good to know about being able to manufacture the parts cheap. Is the expectation that you can buy one of the canisters from walmart/target and hookup to your new high pressure pump to be able to get the levels needed to fill it? I thought the high pressure tank would just take the air and not be able to hookup to another tank. If you can, that is cool that you can pressurize your own helium from the other balloon tanks.

A bit of difficulty has turned up regarding the high pressure fill nipple (apparently only available from China).

Other parts and fittings have been arriving in just a day or two, but coming from China can take months. Estimated delivery is the end of September.

I did find a Staubli two stage quick connect that fits the existing Staubli fill nipple already on the engine perfectly:

https://trowandholden.com/staubli-quick-connect.html

but...

According to the Staubli website specifications, this particular connector is only rated for 16 bar:

https://www.staubli.com/cn/en/fluid-con ... y-rcs.html

Regardless, I made up a fill hose by connecting the Staubli to one of the scuba tank fill hoses. Just had to change the connector on the end.

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Then there is the matter of getting the gas into the compressor intake.

I would actually like to experiment with the engine with NO compression. Also using ordinary compressed air and various other options at different pressures.

How much difference does it actually make? Apparently using compressed helium can "triple" the power output, but I would like to see this for myself.

Triple over what exactly? Not more than compressed hydrogen I don't think.

Is it really worth it?

It would be nice to get the engine up to the 500 psi that is rumored to be the "minimum" operating pressure, (according to a post from Blade Atilla on YouTube as well as the previously referenced article) as a "baseline" for comparison, but, that may have to wait.

I also want to at least purge the engine a few times, mostly just to blow out any possible loose dirt, rust, moisture, contaminants...

I need to turn it so the fill hole is on the bottom.

I'm tempted also, to just go ahead and tear it down while waiting for that fill nipple. That would have the advantage of being able to provide some detailed specs to the machine shop, and satisfy my curiosity.

I did manage to finally get the thing off the truck, sliding it down a wooden ramp onto a dolly. Lowering it down into the basement/workshop will be another project.

I'm having to fit this engine work in between the dozens of other things on my backlog of largely neglected daily chores.

After a 3 week "vacation" to pick up the engine, I have a lot of catching up to do.

[Tom Booth]

This looked better:

https://www.staubli.com/tw/en/fluid-con ... range.html


Staubli, as far as I can find out, doesn't sell direct, but I think, maybe, I may have found a "surplus" connector of this type on eBay:

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I'm a little more comfortable with something rated for 450 bar (6,526 PSI) rather than 16 bar (232 PSI)

I'm keeping my fingers crossed that it actually fits, though the numbers all seem to match up.

[Tom Booth]

This PDF is useful for decoding Staubli quick connect part numbers.

https://www.qplus.nl/media/wysiwyg/PDF/ ... li-RBE.pdf

So, it looks like the one I already sent for from eBay is "HPG" (suitable for high pressure gas) which is the critical factor.

Being able to look up the specs, and then match those up with an exact part number, or alternatively, to see if an available connector (on eBay, or other supply source) has the right specifications.

This came up in a random-ish search. The Staubli site itself is difficult to navigate.

Anyway, looks like I'm out of the woods as far as finding the right quick connect valve. The one I found has all the bells and whistles: socket cap, dust cover etc.

[Tom Booth]

Today I was over at the shop, putting away some things, including a propane torch I had taken with me over to some Amish, to demonstrate a smaller Stirling engine.

Well, with torch in hand, walking past the engine, I couldn't resist seeing what a little heat might do.

Well, applying heat with the torch, and again hitting it with the rubber mallet, the voltage jumped at least 4 fold.

Between 20 to 30 Volts.

Also, the wires connected up to the meter were bare at the end and got too close at one point and while striking the engine, produced some arching, I think.

I separated the wires further as I did not want that to happen again, but I believe I saw and heard a rather strong spark between the wires. Probably enough to give somebody a good jolt. So, if I was not mistaken, that would seem to indicate some pretty good amperage as well

Still not showing any real signs of trying to run, but, I really didn't give it any more heat than I might apply to a little toy engine to get it going, and still no pressurization.

It is nice, though, to see that the engine does seem to be responding to a little heat input.

https://youtu.be/8tp6iUzO3oU

While uploading this video to YouTube I noticed the other video testing this engine with the mallet, seems to have gone a little viral, nearly 3,000 views already. That has to be a record for my little YouTube channel.

[Tom Booth]

That was fast!

I just ordered these, what seems like yesterday. It may have been a few days, but anyway, got them much sooner than I was anticipating.

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I ordered the 100 amp rectifier, then thought maybe 200 amps would be better.

I still don't really know what the output of the engine will be, Amps/Volts/Watts... But..

It doesn't look like the wires coming out of the engine could handle very high amperage at low voltage.

What would be nice is if I could couple the engine with an off the shelf 12 or 24 volt inverter, as these are cheap and plentiful, easily available anywhere locally.

For a higher voltage, that gets into generally higher end inverters for photovoltaic systems and such, that come with a much higher price tag generally.

Let's say the wires can handle 30 amps.

3000 watt output / 30 amps would mean 100 volts.

So Probably I'd need a minimum bank of nine 12 volt batteries to absorb the output from this engine running at full power.

Whatever battery/inverter arrangement I end up using, one or the other of these rectifiers should be more than enough to carry the load.

To start out with, I may just string together some incandescent 100 watt light bulbs for up to 3000 watts straight out of the engine

The same guy offering the Infinia fill valve on eBay also has this:

https://www.ebay.com/itm/304034005255?h ... SwMEZgyRkT

A *solar" inverter that can handle a very high DC voltage input.

I wonder... Up to 550 volts DC input.

[Tom Booth]

It looks like inverter technology has advanced quite a bit and/or "solar" type, mostly grid intertie type inverters have always been capable of accepting high voltage and/or variable voltage DC input.

In other words, a "48 volt" solar inverter for a photovoltaic system is, or should be, or quite often is able to utilize the relatively low voltage DC output in the morning or afternoon as well as the higher voltage during full sun. All the way up to 500 volts (for some models)

But, these type of inverters generally cost about 10X more than a straight inverter rated for the same AC output.

That is, a 5000 watt AC output, 48 volt DC input inverter might cost $200 but will only accept around the rated 48 volts DC input.

A "solar" 5000 watt AC output 48 volt DC input inverter can generally handle much higher DC input, but will cost more like $2000.

The bad news is, for this engine, the more expensive "solar" type inverter is probably what is needed.

The good news is, it should at least be POSSIBLE to couple the Stirling engine with an "off the shelf" solar type inverter AS IF the rectified high voltage DC from the engine were simply the DC output from a photovoltaic array.

It also looks like there are some less expensive "hybrid" inverters on the market that could handle the higher voltage DC input.

The bad news is, every time I find a model that looks like it could do the job and is reasonably priced,...

It is SOLD OUT!

Maybe if put on back order,... get one by the end of next year.

Anyway, I also need to get a better idea of the actual operating output from the engine before ordering anything because, as the maximum DC voltage increases, so does the minimum.

So If I get an inverter that can handle 500 volts input, it might not even "see" less than 150 volts. Won't even turn on.

If the maximum is only 300 volts, then the minimum will be correspondingly lower, maybe 60 volts.

So I need to find an inverter with a voltage input "window" that matches the engine:s output, which, like a photovoltaic system, could be somewhat variable.

All I know so far is it will produce nearly 30 volts just hitting the end with a rubber mallet, though the literature indicates "high" voltage rectified DC output.

Running it on Solar, or running it on a wood stove, the output voltage could vary somewhat as the heat input varies.

I guess the reason for designing the engine with a high voltage output is, lower transmission cost. The power from the engine could be brought down to the inverter without expensive heavy cables.

If I were to build such an engine to sit on a wood stove, I'd probably go with lower voltage and higher amperage, and have the inverter built right in, or at least as close as possible to the engine, lowering the cost of the system.

I'm not really sure why Infinia would mount the inverter, what seems like as far away from the engine/generator as possible. Easier to get at for servicing I guess.

Making the thing "affordable" does not seem to have been that major of a consideration.

Affordable, under government/military contract is a different ballgame from affordable for, well, me, or the average person.

[Tom Booth]

The high pressure fill valve arrived. (The Staubli) but the threads are not the right size to fit the high pressure fill hose, however I did find an adapter:

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But, that is just a normal air line adaptor from the local Tractor Supply for normal pressures up to 150 psi.

It might work, but rather than take a chance, I sent for a similar stainless steel adaptor rated for high pressure at 5000 psi, (at a correspondingly higher price!)

The only thing left to do is,. Figure out what it is going to take to feed the helium into the compressor intake.

I may just try seeing what it can do with just pressurized air, or, maybe that wouldn't be such a great idea, though. I don't think there is much chance of there being any oil in there to explode, and I don't think 500 psi is enough pressure to create that sort of problem anyway.

I also want to rig up something for the cooling system. In particular because it is apparently a permanent magnet alternator, since it is generating power without needing to activate any field windings like an automotive alternator and overheating can kill a magnet.

One day, I think I'd also like to try pressurizing the engine with some home brew Hydrogen straight out of an electrolyzer.

According to the American Stirling website that has so much to say on the subject of exploding Stirling engines, extremely explosive hydrogen is; "a very safe gas to use in Stirling engines for reasons that I won’t get into on this page."...

Hmmm.. well, something for some additional research I guess. For now I guess I'll stick with helium.

[Tom Booth]

Does it make a difference?

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It arrived in practically no time, thank goodness., So, what's next?

Maybe buy a big big balloon, put a small hole in it, then fill it up with helium from the tank at one end and draw the helium out into the compressor at the other?

[danaumer]

Hello everyone,

I am looking for someone who can help me to build a sterling engine to generate electricity.
Something to produce 0.5 to 1 kw electricity, I pay for the parts and his work, it is for a school project.
Thanks,

[Tom Booth]

Hello everyone,

I am looking for someone who can help me to build a sterling engine to generate electricity.
Something to produce 0.5 to 1 kw electricity, I pay for the parts and his work, it is for a school project.
Thanks,

What's the time frame? How soon would this be needed? Any other specifications ? What's the budget? Where are you located?

What do you mean by "help me to build" exactly? Do you have some idea what type of design engine? Alpha, Beta, Gama, Free Piston, Ringbom ?

What heat source would be used?

[danaumer]

Thank you so much for your quick response,
am I allowed to share email here or it is forbidden please? I have the project details and I can email you if it works for you please?

[Tom Booth]

AFAIK there is no particular "rule", but posting your email address online is generally not a good idea.

I don't know as I can actually be of any help.

Maybe you could start another Topic about your Stirling engine project, there are a number of people here that could provide some help or guidance.

I'm in the process of setting up a workshop to build Stirling engines, so the project is interesting to me, but it may be some time yet.

If you need a working engine for next week's science fair or something, that is probably not going to happen

A 500+ watt Stirling engine is actually a pretty tall order.

Maybe an old gasoline engine from a lawnmower could be converted to a Stirling "Ringbom" type engine in a relatively short time, if that is even possible. I think it could be, but that's theoretical, and a potentially dangerous experiment

[Tom Booth]

I think I was fortunate to find this lot of old 100 watt incondesent light bulbs on sale:

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The switches were quite inexpensive as well .

My plan, to test the engine output and provide some kind of controllable, variable load is to wire up a board with all these bulbs and switches.

Incondesent bulbs don't really care much about AC or DC or frequency, so maybe I can get some idea of the actual output (if any) before investing in a more expensive battery bank and inverter.

[Tom Booth]

I guess, maybe it's possible that I'm just extremely stupid and ignorant and just don't get it, but looking over this NASA / INFINIA engine for some time, it seems seriously flawed to me, in terms of design and engineering for high efficiency.

The first thing that struck me is how close together the heater head and cooling jacket are. The whole thing is steel. I would think that immediately heat would be conducted straight through to the cooling jacket, only a few inches from the heater head. Well, maybe it's some special high tech non-heat-conducting alloy of some sort.

Regardless, if I imagine myself as a hot helium molecule just freshly heated up by the hot solar furnace at the end of the engine, it is my mission to deliver that packet of energy I've been entrusted with, all the way through the engine to the piston.

Of course, I may have to pass the "torch" so to speak, along to other helium atoms along the way, but the net effect is the same as if I had to take it all the way there myself.

Well, looking at the layout of the land ahead, there is a regenerator. To begin with things are fine, it starts out hot, but about half way through this tangles mess, it starts getting colder, and colder and colder.

The further along I progress the colder it gets. My torch begins to flicker it's so cold.

Once out of there, all I see is a vast tundra of cold steel surrounded by cold running water. Burrrrrr.

I pull my collar tight around my neck and button up my coat but to no avail. At the last moment before loosing consciousness I manage to pass the torch to another helium atom, but alas, it's traveling the wrong way.

Anyway, the point is, few hot molecules are going to actually get far enough to deliver their payload to the piston.

It seems to me there should be a better was. Granted this is "state of the art" but I think there is still a lot of room for improvement.