Wood boiler add to geothermal

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New Member
Feb 11, 2023
Ontario, Canada
Looking to add a wood boiler to supplement my Geothermal units currently have one 5 ton and one 3 ton each has it's own 60 Gal buffer tank.
Considering a Econoburn which has 42 gal tank/water jacket my system is closed loop glycol, so I was thinking of running the main pipe and have it connected to both tanks with circulating pump. I have read a lot of opinions about storage and was thinking of adding another 60Gal HWT as a storage so my total would be around 220 Gal would that be enough?also is there a easy way of connecting one of my zones like garage as a dump zone? We live on 320 acres almost half is forest so I have a ton of wood to utilize and figure with the electricity going up high the Geothermal is convenient but not really efficient /money saver as it used to be I would live Geo as a buck up or when on vacation etc.. any thoughts? Also do I need a mixing valve or heat exchanger to tamper the temperature going to the tanks? Main floor is i floor with pex in concrete as is the basement and garage up stairs few radiators and pipes in the joists with those aluminium reflectors
Thanks in advance Paul
I would want a lot more storage than that with a gasifying boiler. You should be able to do something yes but practically impossible to say from here how to do it, most would depend on your entire existing system layout and controls. Yes you would want to mix down the boiler fired water temp. There is a huge difference between boiler heated max water temps, and geo generated temps. Your floors don't want to see water that hot and maybe nothing else in you existing system either.
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Sounds complicated and probably to do right more than $10k. What is your current monthly heating cost? Adding 10-20k$ in solar panels would probably have a similar ROI time frame.

How old is the geothermal system?

Only thing I know about wood boilers I have read on the forums here but I’m guessing you would want minimum 300-500 gallons hot water storage for the wood boiler in addition to the buffer tanks. When that fire is roaring and zones aren’t calling you have to dump all that heat somewhere.

How is your insulation and air sealing. That the best bang for your buck. Adding a free standing stove is probably next. Storage tanks are expensive.
Go with an outdoor gasifier, like a HeatMaster G series? (they are approved for indoor use too)
Has some built in storage...and can idle if everything is up to temp...dunno how big your heat load is, but I'd think a G4000 would be able to keep your storage tanks topped off.
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I’m on forced air geo system along with a wood boiler. No matter what system you buy you’ll want to use a water-water plate exchanger to separate them. Water is much more efficient at transferring at a BTU than glycol, and in an open system it you won’t ever have to be replaced like you have to do with glycol. My installer used methanol in my geo system, he’s not a fan of glycol.
I have a Econoburn 200 and have 1000 gallons of storage,wish i had 2000 to give me more freedom from the box
Great responses here are some of mine answers
1. Geothermal is about 10-12 years old
2. Good insulation as that was part of getting partial grant to install the system
3. Solar not very efficient here in the winter Northern Ontario , not many sunny days and short days overall
4. I'm on well water and don't want and open system as we had problems with Geo it was originally open system pipe froze and cracked in the garage floor drained the water from well for days without noticing it also in case there is a power problem and system needs to be off I don't want to drain /blow the whole system so it doesn't freeze this is specially formulated mix called Hypotherm I believe design for hydronic heating .
the way I see it nothing needs to be change all the thermostats are currently tied to 60 Gal buffer tanks so as long as I can deliver hot liquid when is called for it should work. I just need to instal a mixing valve so the water to those tanks will be within range we could also always bump up the heat demand so it will be circulating (we could really use that some days as our current system max out at 23C/73F. so we have it set at 21C/ 70F would love to be at around 23/73
As of now I'm not heating a garage floor as it is costly would like to add that to the whole system
We have a free standing masonry fireplace which is great but only heats up well main floor and partially upstairs if we use it it shuts down the Geo system and then when it comes back on it takes very long time to bring the system to proper running temperature -costly
I can get used Econoburn 150 for reasonable money and was thinking of setting it up in the garage , my garage floor would act as a heat dump which would be the most complicated thing to do as it is hooked up to the Geo so I would have to figure it out how to either bypass it or add that function