rotary displacer stirling

fishsmoker · Post by **fishsmoker** » Thu Nov 27, 2008 1:23 pm

I am close to turn nuts!

I just failed on my at least 10th attempt to create a rotary displacer stirling.

I am using a steel box of 12 inches diameter and 3 inches hight, diplacer is half the volume, runs pretty freely in 2 ball bearings. but when I heat one side up and slowly spin the axle with the diaplacer, the working piston hardly "breathes". it is not connected yet to the crankshaft and the working piston runs well on some other "standard" stirlings.

did someone build a rotary stirling ? someone has an helpful idea or even some pictures or drawings he wants to shrae?

Robinson · Post by **Robinson** » Thu Nov 27, 2008 2:31 pm

Probably an obvious question but is there enough temperature differential between the hot and cold sides?

fishsmoker · Post by **fishsmoker** » Fri Nov 28, 2008 1:11 pm

I started with one candle, 2, 3, (it is christmas time !!!) and finally a torch.

I guess that there is too much volume in the hot area which is not diplaced when spinning. but since my tool equipment is limited to the very basic, it is hard for me to keep the clearances within milimeters

Robinson · Post by **Robinson** » Fri Nov 28, 2008 1:48 pm

You have plenty of heat then, but what's keeping the other end cool? Air/fins/water jacket?

Cartech · Post by **Cartech** » Fri Nov 28, 2008 7:52 pm

I think you are on to something, sounds like too much volume to me as well. Heat will also travel to the cold side easily without some kind of insulating barrier. In my opinion, a rotary will need to be thin and need to be split in half and have an insulator on the bottom plate. That is assuming your heating from the bottom and the displacer assembly is horizonal. Here is an example of a working model here, http://www.emachineshop.com/machine-sho ... ge150.html I've been tossing around rotary displacer ideas for a couple years but have yet to try and build one. Good luck