stirling engine

[ext123]

We are building a stand to test stirling engines. These engines rely on solar energy being focused on Hydrogen filled tubes to work. The tubes need to be heated to 1600 degrees F. We need to simulate this energy on our test stand. The first option is to use a gas fired burner. This does not seem very efficient. The second option we are looking into is using induction heating.
Does any one out there have any other ideas of how to generate this much heat?

 

[roydm]

We have a reactor skid where we heat 316SS tubes by powering up with a low voltage high current transformer, e.g. 6 V 1000 Amps.
Both ends are grounded and the 6 V is connected between ground and mid point. The transformer primary is switched on/off over about a 30 seconds
Roy

 

[itsmoked]

Why not just wrap it with a an electric heater? Then you can easily "dial a temp" and run computerized profiles and tests. Everything else will be more complex. 1600F is not real high.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Pud]

As it's a "test" what's wrong with a gas burner and it's inefficiencies?

Surely you are looking at a longer term "save the planet" goal?

If you are really concerned, try a hydrogen torch with the H2 from wind power!

H

 

[sreid]

How much "Heat" do you need? Or what's the motor HP?

 

[ext123]

We need about 80Kw absorbed power.

 

[analogkid2digitalman]

Don't mean to hijack the thread but what Roy proposed is something I had suggested a few months ago for one of our applications.

Roy- do you have a feel for how consistent the heating is along the length of the tubes?

We current shrink heat shrink tubing over a 3m length of SS stripwound using a 30cm IR tube furnace. It is a long and arduous process for an operator to feed the stripwound through the short furnace. I proposed using a low voltage high current source attached to both ends of the stripwound to heat it up and shrink the tubing over. Only need about 150-220 deg C. Idea didn't get off the ground since no readily available current source on hand but I may get a surplus Xformer now to test the concept.

Any feedback would be appreciated.

Thanks

-AK2DM


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"It's the questions that drive us"
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[sreid]

For an electrical solution, 125 amps of 440 VAC 3 phase service would provide more than 80kW. You might have to upgrade your electrical service to provide this.

You could then design a "Box" to go around the hot end of the engine, install 80kW of heaters in the box. Then control the temperature using a 3 phase SCR switch controlled using a temperature controller with some kind of temperature sensor for feedback (IR Sensor?)

 

[Compositepro]

I would ask what it is you are going to test. If these engines are designed for radiant solar heat absorption would it be best to use radiant heaters for the testing?
That would include the absorbance of the tubes as part of the test. Focused quartz-halogen heaters would do it.

 

[ext123]

Roy my tubes are made of inconel so your idea intrigues me. For my application I do not see a way to attach to all the tubes at once easily. See attached picture.

Compositepro - I looked into into using IR to heat tubes, manufacuturer could not convince me this is the way to go.

If you look at attached picture the bowl on left is where all hydrogen filled tubes are located. In the field the sunlight is focused on bowl to heat tubes.

Our test stand will be used for endurance testing and for production testing. The heating device needs to be fairly simple to attach.

Thanks

 

[itsmoked]

80kW Wow. I don't recall what you can get T3 lamps to.

Perhaps a focused high power arc, or a Xenon lamp.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

Just remembered; somewhere I saw a microwave powered light source for commercial buildings. It was a baseball sized ball that was something like 50kW.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Compositepro]

I would definitely go with radiant heaters in a reflective chamber designed to fit over your absorber. The energy will reflect in the chamber until it is absorbed by you absorber. No insulation required. Actually you will probably want cooling fans.

Try these guys:

http://www.heraeus-noblelight.com/e...eat/products/special-infrared-ir-heaters.html

or

http://www.researchinc.com/infraredbasics.asp

 

[roydm]

It seems from the picture the tubing is very short which would require very low voltage and huge currents, I think you must have some intermediate fluid between your solar and the tubes to avoid hot spots. A fluidized bed perhaps
1,600°F is too hot for oil isn't it?, what about molten metal e.g. lead
Could you attach a tank and heat up with an imersion heater? That would let you monitor BTU input.
Perhaps induction heating is the way to go. you could put a HFreq coil right nect to the tubes in a vacuum so you don't have to insulate.
I'm just throwing ideas out there.
Roy

 

[roydm]

Analogkid2digitalman,
Yes the heating is very even if you get a good contact, just a thought though, could you not do it quicker with hot oil or similar?
Roy

 

[sreid]

Having now seen the picture I think something like a ceramic bowl with imbedded Nicrome wires could be inserted into the hot end cavity. A link below to a company that could probably design and build a temperature controlled unit for you.

http://www.enerpro-inc.com/index.html

 

[analogkid2digitalman]

Roy:

Thanks for the feedback regarding heat distrivution, fluids would leak out of the stripwound and we require cleaniliness of the assembly (medical application).

-AK2DM

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"It's the questions that drive us"
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