Heat storage.....decisions...decisions

[muncybob]

Man, there is a lot to learn about heating with wood! Just a month or so ago I ordered heatintg oil and when I got the bill I said to my wife...THAT'S IT We are buying an OWB!! I thought this was going to be a no brainer...buy one, install and away we go. Well I have learned a lot thanks to the good folks here and the vast internet. I doubt we'll make a purchase until the end of the summer so I still have a lot of time to further enlighten(or confuse) myself. Part of the confusion process lies in the fact that I have almost no plumbing/heating knowledge...but fortunatley I still have enough active brain cells remaining to learn a thing or two.

With all that aside I was just reading nofossil's web site and until then I thought any heat storage must be either inside the house/building or underground. I see his is above ground and he experiences winter temps a bit colder than we do here in PA. While an OWB initial start up cost is considerably less than me putting a gassifier in a newley built/insulated enclosure the less wood consumption with storage does appeal to me. But if the storage tank is outside and above ground don't I run the risk of freezing in the event of possible boiler failure or a power outage? Is storage still viable even if the storage tank is 100' away from the boiler? Will nofossil come to PA and install my system for me??

 

[Nofossil]

Man, there is a lot to learn about heating with wood! Just a month or so ago I ordered heatintg oil and when I got the bill I said to my wife...THAT'S IT We are buying an OWB!! I thought this was going to be a no brainer...buy one, install and away we go. Well I have learned a lot thanks to the good folks here and the vast internet. I doubt we'll make a purchase until the end of the summer so I still have a lot of time to further enlighten(or confuse) myself. Part of the confusion process lies in the fact that I have almost no plumbing/heating knowledge...but fortunatley I still have enough active brain cells remaining to learn a thing or two.

With all that aside I was just reading nofossil's web site and until then I thought any heat storage must be either inside the house/building or underground. I see his is above ground and he experiences winter temps a bit colder than we do here in PA. While an OWB initial start up cost is considerably less than me putting a gassifier in a newley built/insulated enclosure the less wood consumption with storage does appeal to me. But if the storage tank is outside and above ground don't I run the risk of freezing in the event of possible boiler failure or a power outage? Is storage still viable even if the storage tank is 100' away from the boiler? Will nofossil come to PA and install my system for me??

Nofossil only does onsite installations in the Caribbean ;-)

When you look at the temperature difference between stored hot water and the outdoor air, you realize that you need a LOT of insulation. 15" on the sides and bottom and 24" on the top would not be too much.

If it's well insulated, it will hold heat well enough to never freeze. I calculated that I'd be fine if I let my solar panels heat it up in August and then went away until April. Any plumbing would have to be below the frost line or have some other protective measures, though.

Storage can be very far from the boiler, but it should be as close as possible to the heat loads - especially any intermittent loads such as domestic hot water.

You can start without storage and add it later - that's what I did. Plan for it, though.

 

[WoodNotOil]

I can't comment on experience with outdoor storage, but a search on "heat storage" in this forum will unearth a plethera of possible tanks and designs for both pressurized and non. I have a tarm gasifier and my father has a OWB. I can tell you from experience that he burns twice the amount of wood I do. I am about to embark on building a non-press. concrete storage tank in the basement with EPDM liner and hx plate. That will reduce the wood consumption even more. I think 100' is a long way and might impact efficiency, but others can probably give you the specifics on that. The argument for OWB is often that the mess is kept outdoors. Having tended both indoor and outdoor setups, I have to say the mess in the cellar isn't that bad and it sure beats loading oversized logs in below zero windy weather at 10pm in January. If you have a bulkhead and available flue, I suggest getting a gasifier like the Tarm, Eko, or Econoburn. They all get good reviews here.

 

[muncybob]

Well, the Caribbean we are not...although we do get some LL baseball players from there!!

I would love to put the wood boiler in my basement but the available flue situation is the problem as I plan to keep my existing oil boiler as back up. Perhaps I need to investigate the cost of an additional chimney as compared to the cost of running piping 100' to the house? It appears the piping would be fairly expensive even if I dig the trench and lay/insulate myself?

 

[WoodNotOil]

I had the same flue problem. I power vented the oil boiler through the side of the house a few feet above ground level. The power vent blows out the exhaust and disipates it. There is no need to put in a new chimney. My fathers OWB system ended up costing him more than my gasifier in the basement. You have the cost of the slab under the OWB, the buried pipes, the heat exchanger, labor to install it all, etc. I would go gasifier in basement.

 

[muncybob]

Problem with the power venting is the oil boiler is on the west side of the house which is the previaling wind side. Probably not the best choice for location on that. I guess I could have the oil boiler relocated to the east side of the house and put the wood boiler in it's place. To power vent the oil boiler the exit from the building would be between 2 windows...is that a problem?

 

[WoodNotOil]

My power vent is a little low to the ground and on the prevailing wind side of the house, so I sometimes can't have the window open that is just above the vent. It all depends on the wind. I only use the boiler for off season domestic and once I put in the storage it will only be as backup. I think if there is little wind on the eastside, then the windows should not be an issue. This is probably your least expensive option.

 

[Nofossil]

Well, the Caribbean we are not...although we do get some LL baseball players from there!!

I would love to put the wood boiler in my basement but the available flue situation is the problem as I plan to keep my existing oil boiler as back up. Perhaps I need to investigate the cost of an additional chimney as compared to the cost of running piping 100' to the house? It appears the piping would be fairly expensive even if I dig the trench and lay/insulate myself?

Another option - I'm replacing my oil boiler (backup heat and hot water) with a direct vent propane hot water heater. Total cost of components less than $2k, and much more efficient than the oil boiler. That would free up a flue.