Stirling for power generation

[flesvik]

Hi I am in the beginning of my finale project for my bachelor’s degree.

The project is about using a solar reflector to heat up an insulated tank via air witch later in the day can be used to cook food.

This project is for developing countries so there is no power available. We of course need power for the tracing system (the tracing engines) and a fan to circulate the air from the solar reflector to the heat storing tank.
This will be about 20-30 W of power in total.


The easiest way to get this power is of course just to buy a couple of solar panels to power it, but we thought that it wood be cheaper and more interesting to use a stirling engine to power it. And the stirling engine can also produce power even when the sun is gone (from the heat in the heat storing tank).

So I made this drawing in inventor for the engine:


And the files:
(the uploading of the inventorfiles zip faild)

The displacercylinder is 2 times as big as the powercylinder. And i was thinking of adding a regenerator.
The white seksjon in the middle of the displacercylinder is some cheramic to stop heat from being transfered from the hot side too the cold side (figured this out myself (i have not seen anyone else using this)).

My inpiration for the 4 cylinder stirling was from this one:

YouTube - Ideal cycle gamma stirling engine

YouTube - Ideal cycle gamma stirling engine

But because i dont know how to make the sinus swasplate in inventor or in real life i made a crankshaft instead.

The problem is how big it hawe to bee too make over 30 W of power? (anything more is just a bonus (it can power some lights or something like that))
And how shod the seals for the “power piston” and for the axle between the two cylinders be? Would an O-ring work?

[OneAndy]

Interesting.

What material are you going to use to store the heat energy?

[flesvik]

The heat is stored in an isolated stainless steal tank filled with small stones. There is also some vertical aluminum plates in the tank to distribute the heat in the tank.

Our task is really not the heat storing system so i dont really know too much about it but it suppose to be up til 400 degrees Celsius an shod maintain a god enough temperature for coking after 7 days whit no heating (i know it sounds much)

[OneAndy]

So is that 20W-30W estimate the potential power from the engine or real power from the alternator or generator?

[Herbertkabi]

http://www.ent.ohiou.edu/~urieli/sti...s/engines.html
http://ntrs.nasa.gov/archive/nasa/ca...1988002196.pdf
http://www.cnccookbook.com/CCStirlingGenerator.htm

cheers,
herbert

[flesvik]

Originally Posted by OneAndy So is that 20W-30W estimate the potential power from the engine or real power from the alternator or generator?

20-30W is the power we need from the generator so the engine needs to be around 40-50W depending on the generator used and the transmission loss.

I am thinking of encasing the engine an pressurizing it though, so I can make more power with a smaller engine end maybe get better efficiency.

Herbertkabi:
Thanks but i have seen those sites already and didn’t find any indication about how big my engine needs too be too get enough power (but I did get inspired to maybe make a 4 cylinder double acting A-cycle engine instead of a G-cycle engine)

[Tkamsker]

Hello
Did you get your master degree ,..
I am also abouzt to build aprototype of similar engine
Are there some pics or learnings avail ?
I wthink that the way wispergen is doing it is the right way
best reg
thomas