Search found 114 matches

by derwood
Fri Aug 23, 2013 5:32 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

I tried the chore boys. The copper scrubber performed a little better than the wire. It out performed ss scrubber and the fine ss enough to say that copper is better in this case for the heat exchanger. It is puzzling why the regular steel wool did so much better than the others. I can think of many...
by derwood
Fri Aug 23, 2013 2:12 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

[tab=20] I was wondering which property is better for displacer material myself. Slower or faster to dissipate heat. ] Based on my experience the best displacer material would be a material that conducts heat at an extremely low rate and does not store heat. stainless or mild steel doesn't really m...
by derwood
Fri Aug 23, 2013 1:57 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

I picked up two boxes of chore boys today and am going to test later tonight. You read my mind...........
by derwood
Fri Aug 23, 2013 6:33 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

I was able to do another test last night. I had some 14 ga. stranded wire. the strands were a bit bigger than the coarse ss wool. I formed them into a ball and compressed it into the heat exchanger. It out performed both grades of ss wool. The wire diameter was much bigger than the ss wool but I was...
by derwood
Thu Aug 22, 2013 3:48 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

I just completed a test using fine stainless. It ran better than the coarse stainless but not even close to the regular steel wool. Based on this test I think copper wool will do even better. I hope that it can withstand the heat and not burn up. Has anybody ever tried copper wool?
by derwood
Thu Aug 22, 2013 11:45 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Re: Heat Exchanger Design

You might be right about that. The stainless is a scouring pad grade and I have been using that throughout all of my testing. The strands are thicker than the regular steel wool. I have a pile of fine ss laying under my lathe. I will try that tonight and see if it works as good as the regular steel ...
by derwood
Wed Aug 21, 2013 8:54 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Heat Exchanger Design
Replies: 41
Views: 21833

Heat Exchanger Design

I thought I would start a thread to discuss what I have learned about heat exchangers. As some of you know I have been working on a thermal lag engine for quite a while. Hours of testing has revealed to me what makes a better heat exchanger. a couple of days ago I decided to raise the compression on...
by derwood
Fri Aug 16, 2013 8:17 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: 500 watt stirling engine?
Replies: 4
Views: 5368

500 watt stirling engine?

I have seen this engine before. 500 watts just doesn't seem accurate. opinions please.....
by derwood
Wed Aug 14, 2013 9:22 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

I tried some new modifications and the results were very surprising. I made a simple heat exchanger and thinned the stainless tubing around the heat exchanger. I also added a heat deflector to contain the heat around the exchanger. The result was more power with less heat. It is now running at 700 r...
by derwood
Sun Aug 11, 2013 2:09 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

I finally got this engine off the shelf to take one final shot at figuring how it functions. I went back, looked at all of my notes and noticed some correlations. I finally figured out how to manipulate heating delay. Just 1/8 inch in tube diameter made it go from not running with a crank shaft to r...
by derwood
Mon Jul 08, 2013 7:32 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

I had to put this project on the shelf for a while. I have been thinking about going back to work on it soon. These engines seem simple due to the fact that there is only one moving part but in reality the variables seem infinite. I have had time to think and will start testing again soon. If someon...
by derwood
Tue Apr 16, 2013 8:20 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

Good to hear from everyone! As far as the correct name for the engine, any of the three is fine with me. I have learned a lot about these engines over the last three months. All trial and error. I have used miles of ss welding wire. I will share some of the things I have learned based on testing wit...
by derwood
Sun Apr 14, 2013 3:47 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

Dave, I think that a diaphragm version would work well. The cylinder would probably have to be a large diameter and not very deep. The cylinder would need to taper quite quickly like a funnel. This would eliminate dead space in the cylinder and allow for a short but powerful stroke. The engine will ...
by derwood
Sun Apr 14, 2013 1:29 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: large lamina flow build
Replies: 139
Views: 157445

Re: large lamina flow build

Sorry I have not posted sooner but I have been very busy lately. I am still making changes to the heat tube. I have had better success with other designs but if I hade the proper materials available I think this design, with some small changes would be the best. I would like to add that this design ...