Adding hot water loop for heat to an outside hot air furnace, need advice.

[dave_dj1]

Hi, maybe some of you have seen my thread on my outside wood heater I put together, well it works so well that now I would like to add water to the mix and try to get some heat into the house.
http://www.arboristsite.com/showthread.php?154832-My-outside-hot-air-furnace-project

I have an idea, I have a heat exchanger i took out of a cube van a while back, it is aproximately 7-8" deep, 10" or so wide and about 16" long, I was thinking about suspending this inside the plenum of the furnace, piping it to a modine in the house, the modine I have is about 16-18" square, with fan and aquastat.

Do you think the HX in the plenum will provide enough surface area to heat the water consistantly enough?

Would I be better to have a 3/4" coil of copper in the plenum?
I do plan on this being an open system, maybe a little resivoir with a vent on top of the plenum, I plan on using antifreeze because I may not be able to keep the fire going 24/7. I already have a taco circulator that i salvaged. The run from the furnace to the house is aprox 45'. I am hoping ot just help the house out, it's a small ranch with walk out rear, finished basement, the modine would go in the utility room in the basement.
I am open to suggestions, I am just hoping to utilize the parts I have on hand.
thanks

 

[blades]

I am thinking that you be better off with the copper coil, a lot of the newer auto heat exchangers are plastic/ Alum combination and as such would not stand up the the possible temps in the plenum. Tranny and Ac aux coolers seldom see much over 225 deg. Your plenum could see upwards of 400 deg.

 

[dave_dj1]

the HX i took out of the walk-in van is all copper, built like a radiator/heater core. If i am able I will dig it out and snap a pic of it tomrrow.

 

[ericjeeper]

I doubt it will ever get hot enough to overcome the fan

How do you plan on getting the heat into the glycol? A lopp of copper laid on top of the firebox?

 

[dave_dj1]

How do you plan on getting the heat into the glycol? A lopp of copper laid on top of the firebox?

I was planning to put the HX that I took out of the van in the plenum on the furnace.
I'll see if I can sketch something up later and post a crude pic...lol

 

[magna19]

my stove is open on the back and front to a extent,wouldnt wrapping a coil of copper tubing on it work for drawing out some of the heat? just curious.