Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: rosewood on October 19, 2011, 02:29:29 PM

Title: Heat loss thru lines and hx
Post by: rosewood on October 19, 2011, 02:29:29 PM

Just curios to see how much loss in heat I have in my homeade insulated lines. I have 200ft round trip buried lines and 40 plate hx in basement,with no heat load draw I lose about 1deg per hour with circulator running. Does this sound about right? Not that I'm complaining but a friend that is installing a furnace was asking if it's worth buying the good stuff. Also does any one insulate their hx, mines not and throws off a lot of heat. But being in basement I like the residual heat it provides.

Title: Re: Heat loss thru lines and hx
Post by: RSI on October 19, 2011, 03:59:31 PM

It is almost impossible to calculate heat loss that way. There is really no easy way to do it.
If you melt snow off the ground you will know you are losing heat. I have never seen home made lines that don't unless they were buried at least 4' down.

If it is worth getting good pipe depends on if the wood costs anything and how much work it is. Also what you consider the "good stuff"
You can get pipe for $5 to $6 per foot that will probably have less heat loss than anything home made. (I don't know how yours is insulated, just talking about what I have seen)

Title: Re: Heat loss thru lines and hx
Post by: donahuej on October 19, 2011, 04:19:15 PM

I went with the good stuff....just seemed like the right thing to do.  That said the way I tell is a electronic thermo as the water leaves the boiler 177 in my case right now...hot water travels 70' to my crawl space thru Thermopex and the water is 176.2 and on the return side in the crawl I'm 172.4 heading back to the boiler...

Title: Re: Heat loss thru lines and hx
Post by: rosewood on October 19, 2011, 06:28:17 PM

Not looking for calculations,just comparison.looks to be a 2-3deg defferance from furnace to hx,hard to tell cause of gauges ,no increments.

Title: Re: Heat loss thru lines and hx
Post by: mikenc on October 19, 2011, 07:29:28 PM

Mine aren't insulated in basement either. Kinda like you like heat in basement. Have HW unit heater in basement to leave set at 70 deg all winter. Mine lines are homemade to. Work fine so far and don't melt so, but they are well insulated and dry. Ran them inside Sch 40 pvc pipe.

Title: Re: Heat loss thru lines and hx
Post by: RSI on October 19, 2011, 10:32:14 PM

What did you use to insulate them?

Title: Re: Heat loss thru lines and hx
Post by: mikenc on October 20, 2011, 07:54:21 PM

3/4 inch thick armflex on each then wrapped with something called solar guard i believe was the name of it. Then tie wrapped together and wrapped again. Then pulled inside sch 6" sch. 40 pvc pipe.