Woody Biomass via Econoburn

Harvey Ramer

Just completed the design on a new Econoburn install. The system will serve a log home that has an existing staple up radiant system with a propane fired Modcon. Extruded plates will be installed and panel rads added where necessary. The Econoburn will have a 1,000 gallons of buffer tank capacity connected. The buffer tanks are 2, 500 gallon, repurposed propane tanks built into an insulated shell.

I have posted all the design documents and welcome any suggestions and comments on what could be done to improve function or simplify the design.

Thanks
Harvey

hot_rod

This is more of the Euro piping approach. This piping allows heat to go to the building without needing to ramp up the buffers first, yet still pulls from buffer when Econoburn is off-line. I like it better than the flow thru buffer piping.

Also a hydrosep inside would clean up some piping and pumping

The indirect could be in a few different connection spots depending on back up boiler priority, will the wood fire have first choice for DHW, etc.

I'm not following your freeze protection, or need for it? Wood heating is pretty inter-active, hard to let it go un-attended. Extended power outages would be more of a concern, either a generator or a DC circ and a few deep cycle batteries in that critical loop. Or an ECM running off batteries with an inverter may be less $$.

If you want freeze protection circulation, pipe it so the mod con or back up source doesn't heat the buffers, ever.

I think running P2 with a 3 way zone valve might do it without sending heat, just circulation out?

Did you check out the Biomass seminar that Siggy did for NYSERDA? It's around 186 pages!

I think the pdf is posted at the Hearth, in the "boiler room" They did get permission from NYSERDA and Siggy to post it.

Harvey Ramer

hot rod said:

Also a hydrosep inside would clean up some piping and pumping

No lie there. A hydro sep would be nice. Most of this piping is already existing "installed by others" though, including a good micro bubble sep. See photo.

hot rod said:

The indirect could be in a few different connection spots depending on back up boiler priority, will the wood fire have first choice for DHW, etc.

The buffer tanks will have first chance at DHW heating. Any time there is a DHW call, it will check the temp of the tanks. If they are hot enough it'll use them, if not it'll revert to the gas boiler.

hot rod said:

I'm not following your freeze protection, or need for it? Wood heating is pretty inter-active, hard to let it go un-attended. Extended power outages would be more of a concern, either a generator or a DC circ and a few deep cycle batteries in that critical loop. Or an ECM running off batteries with an inverter may be less $$.

If you want freeze protection circulation, pipe it so the mod con or back up source doesn't heat the buffers, ever.

I think running P2 with a 3 way zone valve might do it without sending heat, just circulation out?

The power issue is not a concern here. The HO has a whole house automatic standby genset.

As for freeze protection. The wood boiler and the tanks are located in a detached unheated garage. The HO is a retired engineer and has extensive travel plans for his retired days. The system must be protected and I don't like using glycol on systems with large volumes unless absolutely necessary.

There is a good possibility that the freeze protection system won't be needed however, I have seen -20°F around here. When it gets that cold the rules change. I was also able to add the freeze protection for minimal cost. Way less than the cost of glycol and the cost of components that would entail.

The freeze protection is split into 2 stages. One controller measures the fluid temp in the lower, wood boiler piping that is outside of the insulated buffer tank shell. This controller will energize the wood boiler circ and the small circ that bypasses the caleffi thermo mix valve. This will allow residual heat scavenging from the buffer tanks.

The second controller senses the temp in the bottom of the buffer tanks. Should this one drop below 34°, it will override all system calls and utilize the gas boiler to bring out heat to the tanks. The heat will be coming out through the return line into the bottom of the tanks, therefore it will reach the sensor quickly and return to normal operation. While this is in operation, the indoor freeze circ "shown in the drawing" is energized to move the fluid between the 2 sets of closely spaced tee's. The drawing you showed with the hydro sep, would have eliminated the need for the indoor freeze circ. It would require quite a bit of surgery to get the sep installed though.

hot rod said:

Did you check out the Biomass seminar that Siggy did for NYSERDA? It's around 186 pages!

I think the pdf is posted at the Hearth, in the "boiler room" They did get permission from NYSERDA and Siggy to post it.

I did review this extensively. There is some excellent information in those pages! Siggy has done the Biomass industry a great service. His research and information provided a road map in otherwise largely uncharted territory.

SWEI

Had to go looking for that PDF -- it's here in case anyone else is interested.

hot_rod

I'm anxious to see what you end up with for a control package. that seems to be the part that trips up many installers, finding one user friendly control tho run the package.

my own system is about that complicated and I have two solar controllers running it all.

JSiegenthaler

Hi Harvey,

I just came across your post on biomass heating. Nice to see someone putting so much thought into the design and documentation. Do you do installations in New York State? If so you should look into the Renewable Heat NY program. Some major $$ incentives for systems like this. I will be continuing to write more on biomass based hydronic heating. it's a market this is really gaining some traction in Northeastern US.

siggy

Harvey Ramer

JSiegenthaler said:

Hi Harvey,

I just came across your post on biomass heating. Nice to see someone putting so much thought into the design and documentation. Do you do installations in New York State? If so you should look into the Renewable Heat NY program. Some major $$ incentives for systems like this. I will be continuing to write more on biomass based hydronic heating. it's a market this is really gaining some traction in Northeastern US.

siggy

Thanks Siggy.
I try to do my best

I am not installing in NY. I'm in PA. I searched for any such incentives here but it seems PA is a little behind the curve in that regard.

I look forward to reading your material as you come out with it.

Harvey

Harvey Ramer

The nerve center is built.