Date:         Sun, 15 Dec 2002 12:16:48 -0600
Reply-To:     John Rodgers <j_rodgers@CHARTER.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Rodgers <j_rodgers@CHARTER.NET>
Subject:      External  Heat System for Vans
Content-Type: text/plain; charset=us-ascii; format=flowed

Just doing some Sunday morning musings about heating and cooling the
interiors of the various Vanagon configurations.

Someone has come up with and posted to a web site a relatively portable
AC system for dealing with summer heat, i.e., hanging one of the new
small  115 volt domestic window air conditioners in the passenger window
of the van. If there is power available, either generator or electric
service, that works. So much for the summer heat when camping.

What about dealing with the cold in winter when camping? I know there
are various heaters of various kinds. There are the fuel fired
combustion blower types that are installed under the seat. There are the
catalytic types that work,  but they introduce moisture and some nasty
possibilities, i.e., carbon monoxide poisoning.

My thoughts ran to a visit I made one winter with some Indian folk on
the Yukon River once. It was cold as rip that winter, minus 40F outside.
The family had a steel drum set up as a wood stove. The barrel stood on
end, with a cast iron door on one side, and a cast iron circle on top so
a chimney stack could be mounted. That heater kept their little house
toasty. And they had a tub full of hot water for various uses. The hot
water was generated by thermo-siphon principle. There was a copper tube
wrapped around that drum several times to form a coil. The end of bottom
wrap of the coiled copper was in the bottom of the tub. The upper end
was in the top of the tub. Both ends were in the water. The tube was
completely filled, so there was continuous loop of water with no air in
it. As the cold water in the bottom of the coil heated, it would begin
to rise, displacing the water above back into the tub. At the same time
drawing cold water from the bottom of the tub. Through this process they
had a continuous flow of water heating all the time with no pumps required.

To apply the principle to the Vanagons, and get any flame outside the
van, one could arrange in principle a radiator of some type connected to
a feed and return line, the two ends going to a heating point outside
the van where a propane flame could heat a fluid (water & antifreeze).
The radiator could be installed similarly as the window mount AC, the
heated fluid would rise and as it cooled in the radiator it would settle
back to towards the burner to be reheated again. To distribute the heat
from the radiator, a small low power air circulating fan could be
installed in conjunction to the radiator. If one has a deep cycle
secondary battery in the van it would carry that air circulating fan for
quite a while even with a cold battery, but if the inside of the van
were kept warm, and there fore the battery kept warm, the charge on the
battery would be extended.

This could be totally closed, portable system using flexible hoses, and
could be set up in just a few minutes. I suppose it might even be
possible to integrate connections into the vehicles cooling system so as
to use the onboard heater fans. That would just need to be looked into.
It would require a circulating pump in the fluid circuit, however.

Just mulling the possibilities this morning. Hoping someone with a shop
might tackle this idea and see if would reasonably work.

John Rodgers
88 GL Driver