Hi Neil,

Pressure is going to be an issue. So it thermal conductivity.

1. If the copper pipes aren't kept in contact with the exhaust
header, there won't be much heat transfer.  So you'd have to wind the
copper very tightly to the exhaust in order to maintain contact..
2. Every time you make the fluid change direction, it takes more
energy to push it through the tubing.
3. You are going to need a powerful water pump.

This topic has come up on the type2 list; apparently it was done
successfully on a baywindow bus used at a scandinavian airport
decades ago.
It seems to me that a BA6/Southwind/Propex furnace would be a better
solution.

Happy Trails,

Greg Potts
1973/74/77/79 Westfakia "Bob The Tomato
www.pottsfamily.ca

On 4-Feb-07, at 9:22 PM, neil wrote:

> Hi all.
>
> BION (believe it or not) I have an actual Vanagon question.
>
> On a 2L AC engine. An idea that's been on my mind.
>
> How crazy is this:
>
> Open up heater boxes,
>
> wind 3/8" or 1/2" soft copper pipe around each exhaust pipe,
>
> assemble/install boxes, (plug hot air outlets)
>
> connect copper coils to create a circuit
>
> install pump, heater core, etc.,
>
> run coolant through to provide interior heat?
>
> Other parts would include an expansion tank, fan etc. Likely the
> biggest cost would be the pump.
>
> Hard to answer, but would there be enough heated coolant present in
> system to provide any appreciable amount of heat?
>
> Purely hypothetical, though i do have 2 spare heater boxes.......
>
> Likely someone has tried this before, but I am curious.
>
>
>
> Pax,