Thermally Conductive Tubing Issues

Welcome to the world of materials science and trade-offs! Although I never used one, I know that teflon-tubed shell-and-tube heat exchangers have been used where corrosion resistance was needed. Extra heat exchange area may be required, and you'll have to make sure the material can withstand the pressure and temperature you will throw at it.

well pressure and temperature will be little to no issue, i just need a high thermal conductance from what i've read.

I suppose it goes without saying that if you can maximize the surface area of contact, just about anything will work.

So if you had a lot of small-diameter tubes [small dia = large relative surface area] running in parallel (to achieve the fluid flow you need) and the tubes were coiled to present as much area of contact to the hot fluid (air, water?) moving by, you could achieve the heat removal you're looking for.

true, i'll use as large as i can.

Is that tubing i found sufficient? or is there something better?

I want to use the best reasonable material to cut down on weight as well.

What about using aluminum? Light weight, decent conductivity, soft and bendable, cheap, weldable.

Again, my suggestion is to use a bigger heat exchanger to offset the poorer performance.

Here's some stuff.....You might search GlobalSpec also....
http://www.coolpolymers.com/tubing.asp
http://news.thomasnet.com/fullstory/Heat-Exchangers-feature-thermally-conductive-H2-and-FEP-tubing-583569

What is the cost of PTFE compared to copper?

The situation you describe is pretty vague. I recommend getting samples of a variety of materials and testing them 'in application' yourself.

Look at the tubing used for geothermal heat pumps. It is mass produced for heat exchange with the ground it is buried under. You can get 1/2" to 2 1/2" diameter with various fusion couplings and manifolds. Contact your local dealer for details or search the net.

The thermal conductivity will not get close to metal though. Your expectations for polymers might be a bit unrealistic.

By the way, the tubing does not absorb the heat (at least not much of it), it conducts it to the exterior media if it is colder. Insure good physical contact, mass movement, and keep the exterior media as cold as possible.

Thanks guys i think i got all i need!

These issues have make my work difficult in a decade for so.