Pex as heat exchanger?

[Diesel Dan]

I know this thread is fairly old, but I'll chime in for the sake of posterity . The Greasecar WVO conversion kits come standard with pex hose-in-hose to supply fuel sheathed in coolant-filled heater hose. I've had this system mounted on my Mercedes 300D for the past 3 years and probably at least 30K-40K miles, and have not had any problems. The heat exchanger in the tank is copper, but this gets less heat than the pex. I'm sure the copper is a better heat exchanger, but if you don't need that much heat in a particular part of your system, the pex holds up just fine. Even the brass compression fittings that hold it in place are still holding fine.

 

[dlor1]

So 4 years and 40K miles later the pex is still runnin in my ghetto grease tank. Going to upgrade this summer to a proper tank setup but hey it got me this far.

 

[bus-bro]

Don't think the pex will do well in oil, especially hot oil. Flat plate heat exchangers aren't that bad dollar wise. Copper would work, but vibration can cause it to work harden and crack. Pex might not be compatable with all antifreezes.

 

[grampsbutler]

Is there any reason why you can't use a jacketed aluminum line? This would be really easy to weld up and would transfer heat very efficiently, and the cost of materials would be minimal. So long as you use a have enough wall thickness and you plan to replace every 5 years or so. I can't imagine you would have terrible problems with corrosion. Is there something that I am missing?

Also has anybody tried heating electrically?

Graham

http://www.intrepidequipment.com Intrepid Recumbent Handcycle Specialists, San Diego, CA