Water Cooling Designs

[Hawke]

A new engine in the works and Im wanting to do a cooling system. in My Gallery is a design image that I think will work nicely. Did I miss something?

Also Id like to see some other designs you may have seen or done.

[Hawke]

Maybe the tube depth into the cooling box should be swapped inlet being the higher one. Should the coils be more level or horizontal? I mean like a snaking effect on the same plane?

[fullofhotair]

http://youtu.be/2t5iJB4mSV0
http://www.youtube.com/watch?v=m4cSpevE ... GcKjeBF3LS
http://youtu.be/ZF0J8OvDSmM
Hawke,
I gave you 3 videos. The first is just a straight thermosyphon on a stirling engine. It has a small surface area and poor conductor. The 2nd is a van blade on a stirling engine being used as the flywheel. It produces a lot of air movement. The 3rd is a homemade air conditioner. I would use it just the opposite, as a radiator to get rid of heat. By putting these three ideas together I think you would get a hell of a good cooling system.

[Hawke]

Thx Full,
Ive seen the first two and been pondering them but the last AC one was quite entertaining! I want to build one at work Haha!
Approtechie sure gets some rpms from his engines. The non-machining engines he makes are impressive. I also ran across another just now...
http://www.youtube.com/watch?v=YUmXj-aodPM

1:10 min in.

Do you think a closed tank would do better than an open topped cooling box as in my design drawing? The above video is a closed system. Im not sure if he has cooling tubes and fins inside like you spoke of before.

[fullofhotair]

I think for a thermosyphon to work best it needs a closed system. The hot water rises and enters the cooling system at the top. The cooled water becoming more dense settles to the bottom . Then drops down to the cold side of the engine to be reheated. Iam not positive but I believe a closed system using just copper tubing and no tank would work. Copper coiled around the cold end of the engine.If you could soldier the tubing to the cold end instead of just wrapping it around it would conduct heat away better.The fan and radiator coil have to be above the engines cold end coil.Its really a bad use of words because the cold end of the stirling engine is the hot end of the thermosyphon, and heat rise so its confusing.

[fullofhotair]

http://www.youtube.com/watch?v=nROyfgGx ... XvP5_RYZ8J
Hawke,
If you really want to trick out your cooling system take a look at this video.It is a homemade evaporative cooler. You could use this in front of the fan coil radiator. You would only need one side not two. I would use burlap instead of a t-shirt for better air circulation. This could easily drop the temp. 30 or more degrees depending on relative humidity. The thermosyphon moves more water with a bigger temp difference just like the stirling engine gains speed with a greater temperature difference. A thermosyphon or stirling engine can run on the ambient temperature, not needing any outside heat, if you give them enough cold.

[Hawke]

Now thats a sweet idea Full! Especially this part which I hadnt thought about, makes sense!

...The thermosyphon moves more water with a bigger temp difference just like the stirling.

[fullofhotair]

Hawke,
Ive been trying to do a little more research on it. You might need the tank for the thermosyphon. It seems a tall narrow holding tank is better than a short fat one. You want bigger tubing instead of narrow tubing. Try to avoid real sharp bends .I think youll just have to do some experimenting . You are breaking new ground as far as I can tell.

[Hawke]

[tab=10]More good info Full. After seeing the heat that these stirlings carry, its apparent that the damage a torch can do to aluminum and even steel wool can happen pretty quick. I still havent gotten to the SS displacer cylinder yet but my goal is to get decent power from JUST ONE tea lamp. Fine tuning the cooling is my target at this point. Ive got some ideas on how to do this which I plan to utilize in this new build. As you stated its the temperature difference we need to achieve and not just throw more heat to it.

[tab=10]The thermosyphon is still rolling around in the Theory and Design Department -those guys are so slow :-) however I do have a keen displacer cylinder I'd like to show off. Its going to provide dual opportunities at cooling. My previous engine had epoxy on the top of the displacer cylinder and held up fine so Ive used it there again. Everything below that is high temp silicone sealed. The displacer is steel wool again but if I can resist the torch it my be ok with JUST ONE(did I say one) tea lamp.

[Hawke]

Oh yea, and copper on the cooling end as well to get going with the heat dissipation.

[Ian S C]

My radiators consist of a top and bottom tank, the two are connected by a dozen or more copper or brass tubes. The tubes I prefer come from old radiators used in car heaters, they are flat, about 3/8" x 1/8", and about .010" thick brass. The one I'm working on at the moment has instead about 20 1/4" copper tubes. The thing is to get the maximum surface area on the vertical tubes, and a flow of air through the core. On the motor in my gallery listed as my second one I have a little surplus power on the generator, an it powers a little fan from a computer that blows through the radiator core, on the original design of this motor by James G. Rizzo, the fan was mechaniclly powered. Ian S C

[fullofhotair]

Hawke, Iam really impressesd with what you have so far. Remember just because your limiting yourself to just one tea candle , that doesnt mean you cant improve and speed up its burn. The more air circulation it gets ,the faster it will burn. Insulated material instead of conducting metal for the burn chamber. Maybe a vent tube an inch or so from the top of the burn chamber. Anything you can think of that gives you an advantage over just sticking a candle under your engine.

[Hawke]

Hey thx Full! I was reading a little in Andy Ross's book and saw myself when he described his newbie excitement. I guess we all go thru it(but it does serve to add a bit of freshness to you oldtimers who have been at it longer). There's a part of me very kid-like wanting to be noticed or make some new contribution(see my bold signature, LOL) but alas, its really all been tried before, Im just catching up which in reality makes me the slow poke. Hahaha.


Now back to the business at hand,

Insulated material instead of conducting metal for the burn chamber.

I relate your statement to a heliarc welding torch which uses a ceramic cup around the tungsten tip issuing in the gas shield. The ceramic is a low conductor of heat or insulated material as you say but I wonder why this is important. Is it that the heat will be absorbed and lost somewhat by the burn chamber instead of focused on the cylinder hot section, thereby losing some of the available heat? I can see that as plausible.

[fullofhotair]

Hawke,
Right, if you can feel heat through the sides of the burner ,thats lost heat . Most of the time nobody gives it that much concern, because they are over heating and dont mind waste. If you use one tea candle you need everything you can get. I like the idea of seeing just what one tea candle can produce.
Yes, it probably true that just about everything has been tried, but every conbination hasnt been tried. That leaves you a whole bunch of combinations which will produce totally new results. I personally dont think the stirling engine has come anywhere near its full potential. Just think of all the new materials that have recently been invented. There is a slew of new heat insulator and ways to produce electricity and store it.

[Hawke]

Ive not been able to come up with a viable design using thermosyphon with the above pictured displacer cylinder. The cooling chambers either need to be sealed and provide a closed system, or have a taller chamber and the holding tank of coolant would be lower. I would call this semi-closed. I dont want to waste my current displacer cylinder so Im moving on with the engine and dancing around gravity fed or pumped with engine power. The later is most interesting to me as it could still provide an engine that could run for extended periods only needing evaporated coolant replaced.

I accidentally left something in the build which will lend to an interesting result. More on that later. shhhh....